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Home My WebLink About3402_HanesMillRdMSWLF_PermitAmendApp_LOS_DIN26171_06032016 June 3, 2016 Mr. Ming Chao North Carolina Department of Environment Quality 450 W. Hanes Mill Road, Suite 300 Winston-Salem, NC 27699-1646 Re: Amendment of Permit No. 34-02 Hanes Mill Road Landfill HDR Project No. 00162-264638-018 Dear Mr. Chao: HDR is pleased to submit this permit amendment application for the Hanes Mill Road Landfill on behalf of the Winston-Salem/Forsyth County City/County Utility Commission (the Commission). The Hanes Mill Road Landfill is being operated under North Carolina Department of Environment Quality (NCDEQ) Solid Waste Permit No. 34-02. Under NCDEQ regulations, this permit is effective for five years from the previous Phase I and II Cell 1-4 Permit to Operate (PTO) issued on October 18, 2011 and, therefore, will be effective until October 18, 2016. The Commission is requesting an extension of the solid waste PTO for the landfill. The Phase I and II areas of the landfill have not reached the permitted design grades; therefore, this renewal application addresses the extension request for the permitted operational life to allow full development of Phase I and II. As required by the General Facility Conditions specified in the PTO, the Commission is required to submit a permit amendment to NCDENR by June 18, 2016. Based on our phone conversation on March 22, 2016, NCDEQ requires the following updated documents to be submitted with the extension request. • Engineering Plan • Construction Quality Assurance (CQA) Plan • Operations Plan • Closure and Post-Closure Plans • Water Quality Monitoring Plan The Engineering and CQA plans have not changed since the Phase 2 Permit to Construct Application was submitted in September 2010. Please refer to that submittal as needed. hdrinc.com 440 S Church Street, Suites 1000, Charlotte, NC 28202-2075 704.338.6700 M. Chao June 3, 2016 Page 2 This submittal includes updated copies of the Operations Plan, Closure and Post-Closure plans, and Water Quality Monitoring Plan for your review. In addition we have updated the following documents. • Facility Plan (drawing) • Landfill Gas Monitoring Plan If you have any questions regarding this permit amendment request, please do not hesitate to call me at (704) 338-6843. Sincerely, HDR Engineering, Inc. of the Carolinas Michael D. Plummer, P.E. Project Engineer MDP/apb Enclosures cc: Jan McHargue, Winston-Salem (with enclosures) Edward Gibson, Winston-Salem (with enclosures) Operations Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents Contents Introduction ................................................................................................................................ 1 Standard Operating Procedures ................................................................................................. 1 Waste Screening Programs ....................................................................................................... 1 Waste Receiving and Inspection............................................................................................. 1 Waste Determination Process ................................................................................................ 2 Prohibited Waste Types ......................................................................................................... 2 Hazardous Waste Contingency Plan ...................................................................................... 3 Waste Disposal .......................................................................................................................... 4 Placement of Initial Lift ........................................................................................................... 4 General Procedures ............................................................................................................... 4 Equipment Operations within the Landfill Cell ......................................................................... 5 Procedures for Stormwater Separation ................................................................................... 6 Alternative Daily Cover ............................................................................................................... 6 Concrete, Asphalt, and Brick Operations .................................................................................... 7 Explosive Gases Control ............................................................................................................ 8 Methane Monitoring Well Placement ...................................................................................... 8 Methane Monitoring Program ................................................................................................. 8 Sampling and Analysis Procedures ........................................................................................ 8 Emergency Response Plan .................................................................................................... 9 Sedimentation and Erosion Control ............................................................................................ 9 Leachate Management .............................................................................................................10 General .................................................................................................................................10 Leachate Pretreatment and Discharge ..................................................................................13 Separation of Stormwater ......................................................................................................13 Leachate Quality Sampling ....................................................................................................13 Leachate Contingency Plan ...................................................................................................13 Air Quality Control .....................................................................................................................14 Access and Safety Requirements .............................................................................................14 Spreading and Compacting Program ........................................................................................14 Record Keeping Program ..........................................................................................................15 i City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Introduction Introduction The purpose of this section is to identify protocols for the overall operation and maintenance of the landfill expansion area, which is owned and operated by the City. This plan has been prepared in accordance with appropriate NCDEQ .1600 rules and provides details of the procedures and policies, which shall be implemented throughout the life of the City’s landfill expansion area. Refer to tThe Phase 2 Application to Construct drawings for an illustrate illustration of the existing conditions of the landfill expansion (including known limits of existing and previous disposal areas, and buffer zones); the fill phasing (including the progression of operation including daily operation, transition contours, and final contours); and proposed final contours and erosion control plans (including storm water control, and stockpile and borrow operations). Standard Operating Procedures Hours and Days of Operation The landfill is open for operation between the hours of 7:00 AM and 4:30 PM, Monday through Friday, and from 8:00 AM to noon on Saturday. The landfill is normally closed on Sundays except where prior permission has been given to receive waste for special instances such as a natural disaster. The landfill is closed on Thanksgiving Day and Christmas Day. The landfill is open from 7:00 AM to 3:00 PM on New Year’s Day, Martin Luther King Jr. Day, Good Friday, Memorial Day, Independence Day, and Labor Day. It is anticipated that this schedule will continue, however operational hours and holidays may changes as the need arises. Waste Screening Programs In order to reduce the risk ofassure that prohibited wastes are not entering the landfill facility, waste screening programs have been implemented at the existing landfill. Waste received at both the scalehouse entrance and waste taken to the working face is inspected by trained personnel. These individuals have been trained to spot unauthorized waste, including: liquids, sludges, drums or barrels, and other banned wastes "chemical" odors. Programs for visual characteristics of prohibited wastes are an ongoing part of the existing landfill operation. These programs are implemented in accordance with Rule .1626 Part (1)(f)(4)(b). Waste Receiving and Inspection All vehicles must stop at the scalehouse located at the entrance of the landfill facility. Refuse transportation vehicles are weighed and the content of the load assessed. The scale attendant(s) requests from the driver of the vehicle entering the landfill a description of the waste it is carrying to ensure that unacceptable waste is not allowed into the landfill. The attendant(s) then visually checks the vehicle as it crosses the scale. Signs informing users of the acceptable and unacceptable types of waste are conspicuously posted on the landfill property. 1 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs The Hanes Mill Road Landfill also has a random waste inspection program. Vehicles under this program are selected at random. At least 1 percent of the waste stream (by weight) will be inspected under this program looking for liquid waste, hazardous waste, regulated PCB waste, and other banned items. Selected vehicles are directed to an area usually immediately adjacent to the working face where the vehicle will be unloaded. Wwaste is carefully spread using suitable equipment. An operator attendant trained to identify wastes that are unacceptable inspects the waste discharged at the screening site. If unacceptable waste is found, the load waste will be isolated and secured by coning off the areafor removal. Unacceptable wastes out of the permitted service area will be reported to the NCDEQ Division of Solid Waste Management within 24 hours of attempted disposal. of any waste the landfill is not permitted to receive. The hauler is responsible for removing unacceptable waste from the landfill property. If no unacceptable waste is found, the load will be pushed to the working face and incorporated with the daily waste. Sludges can be accepted at the active landfill, if the sludges pass the paint filter test and the hauler has documentation that the sludge is non-hazardous as defined by NC law. For each vehicle screened, a random waste screening inspection form will be filled out and will be kept on-site. The inspection form should include the following information. • The date and times wastes were received for inspection. • Source and type of wastes. • Vehicle and driver identification. • All observations made by the inspector. • Final disposition of waste after inspection. Waste Determination Process In accordance with 15A NCAC 13B .1626 (f), the Hanes Mill Road Landfill requires documentation and prior approval in order to dispose of special wastes such as contaminated soils, sludge, ash, sandblasting waste, and filter press residue, etc.. The main intent of the special waste program is to ensure that the landfill does not receive hazardous or liquid waste as defined by North Carolina law/regulations. Before special wastes can be disposed at the landfill, a Special Waste Disposal Application must be executed in its entirety, submitted to and reviewed/approved by the City-County Utility Solid Waste Administration. Approval for disposal must be obtained before attempting to dispose of special wastes. Prohibited Waste Types At the present time, Tthe following wastes are prohibited from disposal within the MSW landfill unit. • Whole scrap tires • Used oil • White goods 2 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs • Lead acid batteries • Yard trash • Regulated asbestos waste (friable) • Aluminum cans • Antifreeze • Beverage containers that are required to be recycled under G.S. 18B-1006.1 • Motor vehicle oil filters (after 10/1/2009) • Certain rigid plastic containers (after 10/1/2009) • Wooden pallets (after 10/1/2009) • Discarded computer equipment (after 1/1/2011) Does not include mice and keyboards • Certain Ttelevisions (after 1/1/2011) • Plastic bottlesOyster shells Although friable asbestos waste is prohibited, nonfriable asbestos waste such as shingles containing asbestos are accepted and treated as MSW. In the event that friable asbestos is delivered to the site, it will be treated as unacceptable waste and dealt with in a manner outlined in Section 5.3.3. In addition, operating criteria prohibit other materials from disposal at the MSW landfill unit. These criteria address the following types of waste. • Hazardous waste as defined by NC law. • Polychlorinated biphenyls (PCB) wastes as defined in 40 CFR 761. • Bulk or non-containerized liquid wastes unless the waste is household waste other than septic waste and waste oil; or the waste is leachate or gas condensate derived from the MSW landfill unit, whether it is a new or existing MSW landfill unit or lateral expansion, is designed with a composite liner and leachate collection system. • Containers holding liquid wastes unless the container is a small container similar in size to that normally found in household waste; the container is designed to hold liquids for use other than storage; or the waste is household waste. • Spoiled foods, animal carcasses, and other animal wastes fall into the category of special handling. The generator of the material should call in advance to the landfill, and a determination will be made as to whether or not the waste will be accepted. If the waste is approved, the generator will present the waste at a predetermined time, where an area for disposal will already have been prepared. The waste will be covered immediately. Hazardous Waste Contingency Plan In the event that unacceptable waste is detected at the landfill, appropriate equipment, protective equipment, personnel, and materials as necessary will be employed to isolate the wastes. The NCDEQ Division of Solid Waste Management will be notified immediately that an attempt was made to dispose of unacceptable waste that was generated outside the permitedpermitted Service Area at the landfill. If the vehicle attempting disposal of such waste is known, all attempts shall be made to prevent that vehicle from leaving the site or, if the vehicle 3 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal has left the site, immediate notice will be served on the owner of the vehicle that this hazardous unacceptable waste, for which they have responsibility, has been disposed of at the landfill. The landfill staff shall assist the Division of Solid Waste Management as necessary. If needed, the unacceptable waste will be covered with either on-site soils or other tarping material until such time when an appropriate method can be implemented to properly handle the waste. Should an incident where hazardous waste is found at the landfill occur, the event shall be documented as follows:. • Date and time of material detection. • Hauler name (company and driver). • Material(s) detected. • Material generator(s) if able to identify. • Action(s) taken to manage or return material(s). • Efforts taken if extreme toxicity or hazard was discovered. • Existing Landfill employee in responsible charge. Records of information gathered as part of the random waste inspection programs will be maintained at the landfill expansion during its active life and as long as required by regulation. Waste Disposal Placement of Initial Lift During solid waste placement operations, the landfill liner systems are most vulnerable during the placement of the first lift of solid waste. The first lift of MSW should be comprised of select loads spread on top of the operational cover above the leachate collection layer. These select loads must be free of long or large pieces of waste that may be pushed through the leachate collection layer and damage the liner. The first lift should be a minimum of 4 feet thick and provide sufficient area for at least one day’s operation without placing other areas of the liner in jeopardy. Another area of the liner system that is vulnerable during placement of the first lift of solid waste is the perimeter berms. The protective cover layer against the side wall will protect the liner system. As with the bottom liner, the first lift of MSW against the liner side walls should be comprised of select loads. In the event that the landfill supervisor identifies any damage to any part of the liner system, he should immediately affect its repair. Additionally, he should document the damage and the repair as a part of the operating record. General Procedures Solid waste transportation vehicles will arrive at the working face at random intervals. There may be a number of vehicles unloading waste at the same time, while other vehicles are waiting. In order to maintain control over the off-loading of waste, a certain number of vehicles 4 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal will be allowed on the working face at a time. The actual number will be determined by the traffic spotter. This procedure will be used in order to minimize the potential of off-loading non- acceptable waste and to control disposal activity. Operations at the working face will be conducted in a manner which will encourage the efficient movement of transportation vehicles to and from the working face, and to expedite the unloading of solid waste. This will all be performed in a safe manner. The approach to the working face will be maintained such that two or more vehicles may safely unload side by side. A vehicle turn-around area large enough to enable vehicles to arrive and turn around safely with reasonable speed will be provided adjacent to the unloading area. The vehicles will back to a vacant area near the working face to unload. Upon completion of the unloading operation, the transportation vehicles will immediately leave the working face area. Personnel will direct traffic as necessary to expedite safe movement of vehicles. Solid waste unloading at the active landfill will be controlled to prevent disposal in locations other than those specified by site management. Such control will also be used to confine the working face to a minimum width, yet allow safe and efficient operations. The width and length of the working face will be maintained as small as practical in order to maintain the appearance of the site, control windblown waste, improve operational efficiency, and, when necessary, minimize amount of cover soil required each day. Normally, two working faces will be active on any given day, with all deposited waste in other areas covered by either daily, intermediate, or final cover, as appropriate. The procedures for placement and compaction of solid waste include: unloading of trucks, spreading of waste into 2-foot lifts, compaction on relatively flat slopes using a landfill compactor and a minimum number of three full passes. Uses of portable signs with directional arrows and portable traffic barricades will facilitate the unloading of wastes to the designated disposal locations. These signs and/or barricades may be placed along the access route to the working face of the landfill or other designated disposal areas which may be established. Equipment Operations within the Landfill Cell Both the facilities operational vehicles and solid waste transportation vehicles must be restricted as follows within the landfill cells. • Equipment operation directly on the operational cover above the leachate collection layer shall be limited to rubber-tired vehicles having a maximum ground contact, (i.e., tire low ground pressure, of less than 32 psi.) • A minimum vertical separation of 3 feet shall be maintained between the geomembrane liner and all solid waste transportation vehicles. • A minimum vertical separation of 5 feet shall be maintained between the geomembrane liner and trash compactors or tracked operational vehicles. The operation of vehicles within those portions of the cell not actively receiving waste should be restricted to activities associated with sedimentation and erosion control. Comment [c1]: Paragraph highlighted for Winston-Salem review. Comment [c2]: highlighted for WS review. 5 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Alternative Daily Cover Procedures for Stormwater Separation Each lined landfill cell is divided by berms into hydraulically isolated subcells designed to allow the operator to limit the amount of stormwater entering the leachate collection system. Prior to placement of refuse in a subcell, the subcell must be isolated from the stormwater drainage system and connected to the leachate collection system. Isolation of the subcell from the stormwater system is accomplished by removing the stormwater pipe leading into the next subcell. The subcell is then connected to the leachate collection system by physically removing the geosynthetic rain cover (GRC) over the entire subcell. A GRC will be installed on top of either the operational cover located above the leachate collection layer or previously placed waste/soil cover to prevent stormwater from entering the leachate collection system. The GRC shall be installed according to manufacturer’s specifications. In general, the GRC can be ballasted by anchor trenches, tires, rope, or sandbags, or windscreen. Stormwater runoff is controlled by building up a berm underneath the GRC to act as a diversion ditch. Typically, the GRC is removed by rolling the material in a direction so as to roll it up the slope. Stormwater that has collected in isolated subcells that have not received waste is not considered leachate and may be pumped into sediment ponds as normal stormwater. Alternative Daily Cover At the end of each working day, either six inches of soil, or the following alternative daily cover an NCDEQ Aapproved Alternative Daily Cover (ADC) material, (ADC) will be used to encapsulate exposed refuse. The City’s sources approved options for ADC are listed below. NCDEQ approved material (ADC) is documented in the following: Approved Alternative Daily Cover Materials Forfor Use at Sanitary Landfills, as amended Date of Issue: January 7, 2014 Document number 20365 Examples of approved ADC are: • Construction and Demolition Debris (C&D) Fines • Combustion Residuals (CR) Ash • Spray-Applied Mortar Coating (PpPosi-sShell®) • Synthetic Tarps • Petroleum Contaminated Soils (PCS) • Water Treatment Sludge-Foam Coating • Foundry Sand • Auto fluffAutomotive Shredder Residuals (ASR) • Soil/Mulch mixture Comment [c3]: highlighted for WS review. 6 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Concrete, Asphalt, and Brick Operations The approved ADCs Posi-shell and tarps will be handled and applied by methods documented in the above mentioned document. approved by the manufacturer. PCS will be accepted at the landfill for use as ADC provided it meets the NCDEQ acceptance criteria. For PCS to be accepted on site, the material must have been tested for Total Petroleum Hydrocarbons (TPH). A contamination level of 3,000 parts per million (ppm) or less of TPH is required for acceptance. The material should be tested in accordance with the EPA guidance document SW-846 Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Soils originating from a cleanup or removal of an underground storage tank (UST) or deriving from a spill or other activity regulated under General Statute 143-215, 15 NCAC 2H and 15A NCAC 2C require a Certificate of Approval for Disposal of Soil Containing Petroleum Products (GW-71) issued by the Division of Water Quality or the UST Section of the Division of Waste Management. If the material is not used immediately as ADC the landfill will stockpile the PCS material within the lined landfill. The landfill may stockpile up to 33,000 cubic yards of PCS material based on an estimated average daily cover soil use over a 45-day period. The stockpiled soils shall be covered with a tarp or similar material for storage, or maintained at a moisture level sufficient to prevent blowing dust. Runoff from the PCS storage area shall be directed to the leachate collection system. The landfill shall maintain records in the facility operating record indicting how much PCS was received and utilized for ADC. Water treatment sludges will be utilized as a soil conditioner and incorporated into the daily/intermediate cover. Prior to using Auto fluff and water treatment sludge as daily cover, the landfill will apply for and complete a demonstration project for NCDEQ. As a contingency, the City will maintain a soil stockpile on-site for use as daily cover, should circumstances warrant it. Any area not receiving waste for a period of 12 months will have a minimum of 1 foot of intermediate soil cover. Concrete, Asphalt, and Brick Operations Concrete, asphalt, and brick (CAB) is received, inspected, unloaded and stockpiled at the landfill within the areas shown on Figure 1the Facility Plan-1. A trained inspector will visually inspect every load to assure that only loads of clean, uncontaminated CAB are unloaded and stored at the designated location. Any loads that are found to contain anything other than clean, uncontaminated CAB will not be allowed to unload and will be directed to unload at the working face of the MSW disposal area at the landfill and the hauler will pay the full tip fee for the load unless the hauler chooses to take the load to another landfill permitted to accept such waste. Incidental amounts of glass, sheetrock, plastic and other materials normally found at construction or demolition sites may be accepted during the test projectMaterials other than CAB discovered after unloading and will be properly and safely manageddisposed of at the landfill. Comment [c4]: highlighted for WS review. 7 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Explosive Gases Control Regardless of the amount of CAB received, the landfill will not accept and stockpile more than the capabilities of the storage areas identified. At approximately 50,000 tons of CAB, the landfill will immediately proceed to the final stage of the process, which includes turning the stockpiled CAB into stone for use in Winston-Salem landfillsat the facility. This will involve the retaining of a vendor to crush, chip or otherwise process the large pieces of CAB into useable aggregate. This processed material will then be stockpiled within the same area for periodic use in Winston- Salem landfillsonsite. Explosive Gases Control A gas monitoring system has been constructed around the perimeter of the Existing landfill by a third party. The existing system will be expanded to cover the proposed landfill expansion. This system will monitor for gas migration along the perimeter of the landfill expansion. All buildings and enclosed structures at the landfill will be monitored as part of a routine methane monitoring program. Methane Monitoring Well Placement In accordance with Rule 1626 (4)(b)(I), the following factors were used to determine gas monitoring well placement: soil conditions, hydrologic conditions, hydraulic conditions, and location of facility structures. Monitoring well locations are shown on the Landfill Gas Monitoring Plan provided in the appendicesLandfill Gas Monitoring Plan. Methane Monitoring Program Routine monitoring for gas migration will be performed in accordance with Rule .1626 Part (4)(ba) on a quarterly basis to ensure that the following compliance levels for methane concentration are not exceeded: 1) the concentration of methane gas generated by the facility does not exceed 25 percent of the lower explosive limit (LEL) for methane in facility structures (1.25 percent methane); and 2) the concentration of methane gas migrating from the landfill expansion does not exceed the LEL for methane at the facility property boundary (5 percent methane). The monitoring device that will be used will be a combustible gas indicator (CGI). If concentrations are measured at greater than 25 percent of the LEL for methane in facility structures, then the landfill must immediately take all necessary steps to ensure protection of human health and shall notify the Division of Solid Waste Management. Within seven days of detection, the methane gas levels detected and a description of the steps taken to protect human health shall be placed in the operating record. Within 60 days of detection, a remediation plan describing the nature and extent of the problem and the proposed remedy for methane gas releases shall be placed in the operating record, the remediation plan shall be implemented, and the Division of Solid Waste Management shall be notified. Sampling and Analysis Procedures The City may have an independent contractor perform methane sampling and analysis in accordance with the Landfill Gas Monitoring Plan. 8 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Sedimentation and Erosion Control Emergency Response Plan In the event methane gas levels exceed allowable limits within structures, the emergency response plan will be as follows. • For structures with greater than 25 percent LEL: o evacuate immediately, leaving doors open, o notify Winston-Salem Fire Department Hazardous Material Team, o notify NCDEQ, o notify consulting engineer, and o follow emergency procedure outlines in 15A NCAC 13B.1626(4)(c). • For structures with 0-25 percent LEL: o conduct follow-up monitoring, and o discuss with consulting engineer. Sedimentation and Erosion Control The landfill expansion area will be constructed with maximum waste sideslopes of 3H:1V and minimum 8% top slopes to promote runoff and prevent ponding over or in the waste. Side slope terraces and perimeter drainage channels at the toe of the slope will provide runoff, erosion, and sediment control. The drainage channel allows for the movement of surface water from landfilling activities and provides a settling zone for sediments carried from the site. The channel is constructed to allow drainage via sediment basins through natural outfalls and tributaries to Grassy Creek. Measures to control sedimentation and erosion will include the drainage channel, sediment basins, silt fences, slope drains, sediment traps, temporary and permanent seeding. Within 30 working days or 120 calendar days of completion of any phase of landfill development a vegetative ground cover sufficient to restrain erosion will be accomplished. All measures will be constructed or installed in accordance with standards specified in the North Carolina Erosion and Sediment Control Planning and Design Manual. Sediment basins will also prevent the discharge of pollutants that violate requirements of the Clean Water Act, including, but not limited to, NPDES requirements, into the waters and wetlands of the United States. The landfill expansion area will have a comprehensive surface and groundwater monitoring program to provide early detection of any leachate migration problems. In the event any constituents are detected above allowable limits, measures will be taken to begin assessing the extent of contamination and, if necessary, corrective actions will be taken to prevent the pollution of waters and wetlands of the United States, that violate any requirements of an area- wide or state-wide water quality management plan that has been approved under Section 208 or 319 of the Clean Water Act, as amended. 9 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management Leachate Management General Collection and removal of leachate generated from waste within expansion landfill will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, they will be cleared of debris using the cleanout riser pipes for access. The maintenance and cleaning will be performed on an annual basis or as necessary basis to maintain the free flow of leachate in accordance with NC General Statutes 130A-295.6(h)(3). The facility reserves the right to request that the Department allow the leachate lines to be cleared every two years, also in accordance with NC General Statutes 130A-295.6(h)(3). The pipes will be cleaned with jetted water and all cleanings will be recorded on the Leachate Pipe Cleaning Form. If pipes are damaged, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Remote camera inspections of the leachate lines will occur upon completion of construction, at least once every five years, and following the clearing of all blockages in accordance with NC General Statutes 130A-295.6(h)(3). Records of the inspections will be recorded on the Remote Camera Video Inspection Form. The Phase 2 collection system includes collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C, respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the existing landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. 10 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Cleaning Report in the file. Leachate Pipe Cleaning Form* Pipe ID Date Cleaning Company Persons Operating the Equipment Comments about Cleaning Comment [c5]: WS to confirm the use of this form 11 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Inspection Report in the file. Remote Camera Video Inspection Form* Pipe ID Date Inspection Company Persons Operating the Equipment Comments about Inspection 12 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management According to the letter dated September 13, 2005 from the City/County Utilities Department, the landfill is not required to have a permit to discharge leachate at the wastewater treatment plant. Leachate Pretreatment and Discharge At this time, leachate pretreatment is anticipated to consist of only equalization in the storage tanks. Existing on-site leachate quality tests do not indicate a need for pretreatment at this time. Testing of leachate quality will continue during the life of the Hanes Landfill facility. Dependent on the outcome of future tests, an appropriate system, if required, will be designed. Separation of Stormwater Storm water control measures will be employed within lined subcells which have not received waste. These measures include “sectioning off” unused subcells or portions of subcells by employing GRC and temporary subcell divider berms. In addition, a sump will be created at the low end of the subcell to facilitate stormwater removal. In general, temporary sumps are formed where the subcell divider berms intersect the perimeter berm. Stormwater drains toward the temporary sumps on top of the GRC. The formation of temporary sumps permits stormwater to be pumped as required. In this way, the landfill expansion operator retains a degree of flexibility throughout the life of the landfill expansion. As filling operations are initially proceeding, stormwater from unfilled subcells is kept out of the leachate collection system. The temporary sumps also enable the operator the potential to monitor both the quantity and quality of leachate and enable separation or isolation of specific areas in the event of a problem. Prior to the commencement of filling activities in the subcells, the temporary discharge pipes will be removed to prevent discharge of leachate into an inactive subcell. Leachate Quality Sampling Semi-annual sampling will be performed in accordance with .1626(12)(c). Samples will be recovered as grab samples from the leachate storage tank. The parameters to be analyzed will include BOD, COD, temperature, conductivity, phosphate, pH, ammonia, suspended solids, sulfates, nitrates, and metals analysis. Analyses will also include a volatiles scan. Please refer to Section 6.0the, Water Quality Monitoring Plan, of the Design Hydrogeological Report for more detail. CFR 258 Appendix I outlines the list of metals and volatiles to be tested. Leachate Contingency Plan In the event that leachate levels within the first tank reach the freeboard capacity, a high crossover pipe will allow flow into the second tank. In the event that both tanks reach the freeboard capacity due to unforeseen events, the excess leachate will either be piped directly to the sewer and then to the POTW or stored temporarily in the landfill expansion. Engineering structures (secondary containment) have been constructed to prevent leachate from entering local waterways. If operational conditions allow, leachate recirculation may be performed with prior NCDEQ approval. 13 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Air Quality Control Air Quality Control Mandates of the US Environmental Protection Agency (EPA) Clean Air Act and corresponding Forsyth County regulations will be met as they become effective. The primary control mechanism will be the proposed active gas extraction system. All equipment at the facility will have fire extinguishers on board. The extinguishers will be properly classified and inspected. All operators will be trained for proper use of extinguishers. Open burning of solid waste is prohibited at the site. The fire department will be notified in cases of emergency, such as a landfill fire. NCDEQ will be notified by a phone call within 24 hours of a landfill fire. A follow-up report detailing the nature of the fire and any respective action taken will be mailed to NCDEQ within 15 days of the landfill fire. Access and Safety Requirements The facility is almost totally enclosed by a 6-foot chain link fence with triple strands of barbed wire to prevent unauthorized entry into the site. Areas currently not protected by fencing are inaccessible by motor vehicle due to steep water barriers, railroads etc. The access road to the working face will be of all-weather construction and kept in good condition. Dust control and tracked mud will be controlled on the access roads as needed. Proper signage directing and informing facility users will be placed in high visibility areas, including signs stating that no hazardous or liquid wastes can be received. Removal of MSW from the facility will not be allowed without the approval of the facility supervisor. Under no conditions will the removal of MSW from the working face be allowed. No barrels or drums will be disposed of at the facility without sufficient perforations to ensure that no liquid or hazardous wastes are contained in them. The facility will be staffed during all operating hours to ensure operational compliance. Spreading and Compacting Program Incoming waste at the facility will be confined to the smallest most efficient working face feasible. Solid waste will be compacted as densely as practical into cells. Appropriate control devices such as berms, fences, and cover material will be used as needed to prevent windblown debris. Any windblown debris will be collected by on-site staff or temporary laborers.. The landfill also has a litter control program. For example, the landfill has installed litter control fences that help capture blowing litter. In addition to these fences, labor is also used to manually remove the blown litter that lies outside the environs of the working face. In the event of extremely windy days, temporary labor and/or prison/community service labor will be used to remove the blown litter. This windblown litter will be bagged and returned to the working face. 14 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Record Keeping Program Record Keeping Program Records for tonnage and waste generators will be kept at the office of the City’s Solid Waste Administrator and made available to NCDEQ upon request within a reasonable period of time. Records for facility inspections, gas/groundwater monitoring results and corresponding analytical data, closure/post-closure cost estimates, financial assurance documentation and employee training will be kept at the facility. The information will be made available to NCDEQ upon request within a reasonable period of time. Copies of the operation plan will be kept at the facility. 15 Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents Contents Cap System Background ........................................................................................................... 1 Cap System Design ................................................................................................................... 1 Final Contour Requirements ...................................................................................................... 2 Cap System Material Requirements ........................................................................................... 2 Surface Water Control Measures ............................................................................................... 2 Permanent Erosion Control Measures ....................................................................................... 3 Settlement Subsidence and Displacement ................................................................................. 3 Leachate Control ........................................................................................................................ 3 Gas Collection/Venting System .................................................................................................. 3 Schedule for Closure.................................................................................................................. 3 Notice of Closure and Date of Final Waste Acceptance ............................................................. 4 Implementation of Closure Plan ................................................................................................. 4 Closure Verification .................................................................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Cap System Background Cap System Background In compliance with the NCDEQ Solid Waste Management Rules, the landfill expansion will place a final cap system over all waste placed in the proposed expansion. The layers of the cap system will be designed and constructed in accordance with Rule .16247 (bc) (83), (9), and (15), to minimize infiltration and erosion. It is estimated that the total landfill volume at completion will be 12,200,000 cubic yards for the 90+/- acres foot print. The maximum area requiring a cap at any one time shall be 65 acres. Cap System Design The desired cap system design may change as new technologies develop. The cap system designed will be checked prior to closure, revised and updated permitted as appropriate. Compacted soil liners will be incorporated in the cap system design to provide protection throughout the 30-year post-closure period and beyond. The regulatory prescriptive system will consists of four layers (bottom up); the compacted soil liner; a geomembrane; a drainage layer (possibly a geonet layer or more appropriate layer); and the erosion layer. The geomembrane and compacted soil liner form a composite barrier designed to reduce infiltration into the landfill expansion, thus minimizing leachate and the potential for groundwater contamination. The erosion layer is designed to protect the composite barrier. The expansion landfill may use on-site or off-site borrow material for the compacted soil layer. The compacted soil layer will consist of no less than 18 inches of soil having permeability equal to or less than 1 x 10-5 cm/sec. In order to assure that the material meets the permeability criteria, the soil will be tested prior to use and after placement. Testing requirements will be outlined in the final closure plan. It is anticipated that the upper 6 inches of the intermediate cover will be suitable for compaction and incorporation into the compacted soil layer. Construction methods for the compacted soil liner shall be based upon the type and quality of the borrow source and shall be verified in the field by constructing test pad(s). A professional engineer shall certify that the compacted soil liner installation conforms with the plans approved by the NCDEQ Division of Solid Waste Management. While NCDEQ rules require that the erosion layer shall consist of no less than 6 inches of earthen material capable of sustaining native plant growth, it is anticipated that the erosion layer for closure of the expansion landfill will consist of 12 inches of suitable on-site borrow material. That 12-inch layer will then be covered with a 6-inch topsoil layer. The materials of the erosion layer will be selected considering: soil type, nutrient levels, pH, erodibility, sideslope drainage, and other factors. The vegetation (typically Kentucky Fescue) should be selected based on the following criteria. • Species of grasses which are locally adapted and resistant to drought or temperature extremes. • Having roots which will not disrupt the low permeability layer. • Ability to thrive in low nutrient soil and develop a good stand to resist erosion. Formatted: Superscript 1 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Final Contour Requirements • Able to survive and function with little or no maintenance. All cover material will be free of putresibleputrescible material, solid waste, vegetation, rocks, construction debris, frozen soil, and other deleterious materials. Seismic and general slope stability analyses have been performed and can be found in the Appendix Phase 2 Application to Construct. Final Contour Requirements The final contour requirements for closure are shown on the drawings included with theis Phase 2 permit Application to Constructamendment. These contours have been established to reflect all municipal solid waste expected to be received, intermediate cover material (representing an initial total of 12 inches and a final total of 6 inches), and the final cover system (representing a total of 3 feet). Cap System Material Requirements Based on the cap design submitted in this amendment, 18 inches of compacted soil placed over the Phase 1 and 2 areas at final closure, 157,000 cubic yards of compacted soil will be required for the first layer of the cap system. A minimum of 105,000 cubic yards will be required for the erosion layer soil. An estimated 52,500 cubic yards of earthen material will be required for the 6 inches of top soil layer. An estimated 2,831,400 square feet of geomembrane will be used in drainage ways and on the top slopes of the completed landfill. The following table summarizes the cap system requirements for Phases 1 and 2 of the landfill expansion area. Table 5-1 Cap System Requirements - Phases 1 & 2 Material Quantity 18-inch Compacted soil liner 157,000 CY 12-inch Erosion layer soil 105,000 CY 6-inch Top soil layer 52,500 CY Geomembrane 2,831,400 SF Surface Water Control Measures The landfill expansion area is designed to have top slopes of 8 percent and side slopes of 3H:1V. Final contours have been established to allow the landfill expansion surface water to drain off the final cover while limiting erosion potential and maintaining post settlement slopes greater than 5 percent. Surface water runoff from the top slopes is intercepted by a diversion berm that separates the top slopes from the side slopes and carried off of the cover via down pipes. The side slopes incorporate a system of drainage terraces to limit surface water flow length. The vertical spacing of the side slope terraces is approximately 40 feet. The side slope terraces will drain into the down pipes which, in turn, drain to the perimeter drainage channel. The surface waters will be conveyed by the perimeter drainage channel to one of four sedimentation basins located adjacent to the landfill expansion. The maximum length of sheet 2 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Permanent Erosion Control Measures flow (~300 ft) will occur on the 8 percent slopes. Drainage terraces will direct flow across the 3H:1V percent slopes into the down pipes and into the sediment basins. Permanent Erosion Control Measures The expansion landfill is situated near an intermittent stream at the southern end of the site and adjacent to Grassy Creek. A system of drainage channels and sedimentation basins will be used to protect the intermittent stream and Grassy Creek from sediment laden runoff. The sedimentation basins were designed to control the 25-year storm event and achieve a minimum of 70 percent efficiency in settling a sediment particle with a diameter of 40 microns. The sedimentation basin design calculations may be found in the Application to Construct calculations section. Settlement Subsidence and Displacement Landfill compaction methods which include the use of steel-wheeled compaction equipment to spread and compact in layers not to exceed 2 feet in thickness, combined with an adequate number of passes over each layer of waste, will be utilized to reduce voids and minimize differential settlement. Proper placement of daily, intermediate, and final cover will reduce the moisture content of the waste prior to site closure and further reduce settlement. Final slopes of the landfill expansion have been developed to allow for this anticipated subsidence so that long- term positive drainage of the fill will not be hindered. Leachate Control The installation of the final cap system over the fill area will greatly reduce infiltration of surface water and lessen the potential for leachate generation. The landfill expansion area has a comprehensive surface and groundwater monitoring program to detect any potential leachate migration problems. This program, which is discussed in Section 8.0 of this documentWater Quality Monitoring Plan, will be continued throughout the post-closure care period. Gas Collection/Venting System It is anticipated that aAn active gas venting system will be installed under the cap to allow movement of gas generated from the completed fill area to the existing gas collection system. The gas collection system will be an extension of the one used at the existing landfill. The collection system is presently maintainedcontrolled by an independent contractor. Schedule for Closure The closure will begin after completion of a portion of the final grades as soon as possible. The design of the landfill expansion in combination with the maintenance plan should assure a fairly uncomplicated closure period. The closure of the entire unit, or portions thereof, will be completed within 180 days unless an extension has been requested and received due to changes in the anticipated schedule. Comment [c1]: Highlighted for WS review 3 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Notice of Closure and Date of Final Waste Acceptance Notice of Closure and Date of Final Waste Acceptance A sign indicating the anticipated date of closure and the date of final waste acceptance will be conspicuously posted at the facility at least 30 days in advance. The landfill may take other steps to notify the public of the planned closure. Prior to beginning closure of the unit or portions thereof, the NCDEQ Department of Solid Waste Management will be notified that a notice of intent to close has been placed in the operating record. Implementation of Closure Plan The closure plan will be implemented as soon as possible from the date of final waste acceptance and completed in accordance with state regulations. Closure Verification The following procedures will be implemented following closure. • A Construction Quality Assurance (CQA) report shall be submitted to the NCDEQ Division of Solid Waste Management. This report shall describe the observations and tests used before, during, and upon completion of construction to ensure that the construction materials meet the cap design specifications and the construction and certification requirements. The CQA report shall contain as-built drawings. • A signed certification from an independent registered professional engineer verifying that closure has been completed in accordance with the closure plan will be submitted to the NCDEQ Division of Solid Waste Management. • At least one sign notifying all persons of the closing of the phase and that wastes are no longer accepted will be posted. Suitable barriers will be installed as necessary at former accesses to prevent new waste from being deposited. • Within 90 days, a survey plat, prepared by a professional land surveyor registered by the State, indicating the location and dimensions of landfill disposal areas, will be submitted to the Forsyth County Register of Deeds circuit court clerk of the City.. • A notation shall be recorded on the deed notifying any potential purchaser of the property that the land has been used as a solid waste management unit and that future use is restricted under Paragraph (8) of Rule .1627. A copy of the deed notation as recorded shall be filed with the operating record. 4 Post Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents Contents Introduction ................................................................................................................................ 1 Post-Closure Contact ................................................................................................................. 1 Description of Use ...................................................................................................................... 1 Maintenance .............................................................................................................................. 1 Repair of Security Control Devices ......................................................................................... 1 Erosion Damage Repair ......................................................................................................... 2 Correction of Settlement, Subsidence and Displacement ....................................................... 2 Leachate Collection System ................................................................................................... 2 Closure of Storage Tanks ....................................................................................................... 3 Repair of Run-On/Run-Off Control Structures ......................................................................... 3 Gas Collection/Venting System .............................................................................................. 3 Groundwater Monitoring System ............................................................................................ 3 Monitoring Plan .......................................................................................................................... 4 Inspection Frequencies .......................................................................................................... 4 Quarterly Inspections .............................................................................................................. 4 Semi-Annual Inspections ........................................................................................................ 5 Engineering Certification ............................................................................................................ 5 Tables Table 1 Post-Closure Inspection Frequencies ........................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Introduction Introduction This Post-Closure Plan has been developed to outline steps to be taken to ensure the environmental soundness of the landfill expansion during its post-closure care period. The post- closure period begins when the Closure Verification Report is submitted to NCDEQ. The post- closure care period will be in accordance with the latest NC regulations, 15A NCAC 13B .1627 (d).last at least 30 years after closure completion and at a minimum and will consist of the following. • Maintaining integrity and effectiveness of final cover system. • Performing groundwater and surface water monitoring. • Maintaining and operating a gas monitoring system. • Maintaining run-on/run-off controls. No wastes will remain exposed after closure of the unit. Access to the closed site by the public or domestic livestock will not pose a health hazard. Post-Closure Contact All correspondence and questions concerning the post-closure care of the unit should be directed to: Solid Waste Administrator City of Winston-Salem Hanes Mill Road Landfill 325 West Hanes Mill Road Winston-Salem, NC 27105 336-747-7310 Description of Use After filling operations cease at the landfill expansion area and the unit is officially closed in accordance with the Closure Plan, the area will be allowed to return to a natural vegetative state. The City will maintain control of the property. The City may develop the land for recreational uses such as greenways, parks, etc. There will be an access road on the cap to allow proper maintenance during post-closure. Final location of the access will be determined as a part of operations. Maintenance Repair of Security Control Devices All security control devices will be inspected and maintained as necessary to ensure access to the site is controlled. Locks, vehicular gates, and fencing will be replaced if functioning improperly. Warning signs will be kept legible at all times and will be replaced if damaged by inclement weather or vandalism. 1 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance Erosion Damage Repair If erosion of the final cover occurs during post-closure, the affected area will be repaired and re- seeded as necessary. Excessive slopes will be flattened if possible by adding clean fill material. If necessary, erosion control fabrics will be used to expedite rapid re-vegetation of slopes and to secure topsoil in place. Rough surfaces which cause isolated erosion areas will be smooth and re-seeded as necessary. Correction of Settlement, Subsidence and Displacement Slopes will be maintained in order to prevent ponding and allow for proper drainage without infiltration. If vertical or horizontal displacement occurs due to differential settlement, cracks will be filled with appropriate material and final cover will be reestablished. Excessive vertical displacement is not anticipated. Leachate Collection System Collection and removal of leachate generated from waste will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, the pipes will be cleared of debris using the cleanout riser pipes for access. All leachate collection lines shall be designed and constructed to permanently allow cleaning and remote camera inspection. All leachate collection lines shall be cleaned as found necessary for proper function and to address buildup of leachate over the liner. at least once per year, except that NCDEQ may allow leachate collection lines to be cleaned once every two years, if the facility has continuous flow monitoring and the permit holder demonstrates to the NCDEQ that the leachate collection lines are clear and functional based on at least three consecutive annual cleanings. Remote camera inspections of the leachate collection lines shall occur at least once every 5 years during the post closure period and following the clearing of blockages. If leachate pipes fracture, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Although total failure of the leachate collection system is unlikely, it may be possible to remove leachate from sumps constructed at the natural drainage points inside the lined area. The Phase 2 system includes leachate collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the closed landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. The sideriser pumps will be maintained in good working order throughout post-closure. Since leachate volume will be decreased during post-closure, the maintenance schedule will be adjusted in accordance with manufacturer’s recommendations. As during landfill operations, a 2 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance high-level alarm system will be in place to warn of pump failure or other system breakdowns. Further, due to the design of the system, the high-level alarm will serve as a monitoring system for prevention of greater than 1 foot of leachate head on the liner system. Closure of Storage Tanks After closure of the landfill expansion area has been achieved, the generation of leachate will eventually curtail. The flow rate immediately after closure should decrease to less than 100 gallons/acre/day (gpapd). Toward the end of the 30-year post-closure period, the flow should approach zero, at which time the storage tanks will not be required. The following procedures will be followed to properly close the storage tanks. • Completely drain and remove all liquids, sludges, sediments, etc. from the storage tanks. • Disassemble the tank, piping, and appurtenances and dispose of the contents in a manner approved by NCDEQ. • Sample and analyze the soil for appropriate constituents inherent to leachate. Assess the results for evidence of contaminant migration. • If contamination of underlying soils is exhibited, perform an assessment as to the degree of contamination and develop remedial actions. • Obtain approval of NCDEQ for the assessment and associated remedial measures. • Perform the remedial actions as necessary to limit any threats to public health and the environment. • Install permanent vegetation in the vicinity of the containment area. Activities may include filling, grading, topsoiling, and seeding. Repair of Run-On/Run-Off Control Structures All side slope terraces, ditches, and perimeter channels will be repaired, cleaned, or realigned in order to maintain original condition. Any culverts that are damaged will be replaced. Gas Collection/Venting System The landfill gas collection and venting system will be maintained. Currently, a third party manages and operates the existing gas system. Proper operation of the systems is verified through testing at the landfill gas monitoring wells and probes. If methane gas recovery wells do not function as a result of irregular settlement, accumulation of liquids (condensate, leachate, and water), binding or corrosion, replacement wells can be installed if necessary. Non-functioning vents will be reset if necessary. Groundwater Monitoring System A Water Quality Monitoring Plan (WQMP) is included as Section 6 this amendment. Procedures outlined in the WQMP, or subsequent revision, will take precedence over the brief description provided here. All groundwater monitoring wells have been installed with concrete pads and protective casings to prevent accidental damage by vehicles and equipment. The wells are also equipped with a locking cap to discourage vandalism. Groundwater wells will be inspected regularly (at the time of sampling) to ensure integrity. Persons inspecting a well should look for 3 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Monitoring Plan signs of well tampering, cracking or degradation, and determine whether the well needs to be replaced. If the decision is made to replace and abandon a well, the replacement well should be installed 5 to 10 feet from the abandoned well in accordance with previous well specifications. Well abandonment should be accomplished by pulling the casing out and grouting the hole. Refer to the approved Water Quality Monitoring Plan for detailed information on the groundwater monitoring system Monitoring Plan The closed unit shall be monitored in accordance with 15A NCAC 13B .1627 (d)for 30 years. A series of inspections shall be scheduled to ensure the integrity and effectiveness of the cap system, storm water control system, groundwater monitoring system, gas collection system, and to protect human health and the environment. Inspection Frequencies Inspections to be conducted during the post-closure care period will occur regularly as shown in Table 7-1 below. A copy of the Post-Closure Inspection Checklist is included at the end of this sectiondocument. Table 1 Post-Closure Inspection Frequencies Inspection Activity Years 1-3 Years 4-30 Security Control Devices Quarterly Quarterly Cover Drainage System Functioning Quarterly* Semi-annually Leachate Collection System Quarterly Semi-annually Gas Collection/Venting System Quarterly Semi-annually Groundwater Monitoring System Semi-annually Semi-annually Erosion Damage Quarterly* Quarterly Cover Settlement, Subsidence, and Displacement Quarterly* Semi-annually Vegetative Cover Condition Quarterly* Quarterly Stormwater Control System Quarterly* Quarterly Benchmark Integrity Annually Annually Leachate Collection Pipe Flushing Annually Annually * These items will also be inspected in accordance with the current NPDES Permit. within 5 days of each major storm event (i.e., 1 inch or greater in any 24-hour period.) Quarterly Inspections Quarterly inspections of the closed site will include examination of the security control devices for signs of deterioration or vandalism to ensure access to the site is limited to authorized persons. The previous disposal area will be checked to ensure the integrity of the final cover system is maintained, erosion damage is repaired, vegetative cover persists, and that cover settlement, subsidence and displacement are minimal. Drainage ditches will be cleared of litter and debris and benchmark integrity will be noted and maintained. 4 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification Semi-Annual Inspections Semi-annual inspections of the site during the post-closure period will be conducted by the City’s engineer with attention paid to integrity and drainage of the final cover system and proper functioning of the groundwater and gas monitoring systems. Groundwater monitoring will continue on a regular basis throughout the post-closure care period. The parameters chosen for analysis will be no less than the requirements of regulatory agencies. Groundwater monitoring wells will be inspected in accordance with the post-closure inspection protocol. A report of findings will be made to the responsible party via the Post- Closure Inspection Checklist, including any recommendations for actions necessary to ensure the site continues to meet the closure performance standard. The engineer will also receive copies of the quarterly inspections reports and respond to any comments that demand immediate attention. Engineering Certification Based on the City’s monitoring reports and an engineer’s semi-annual site visits, annual certifications by the engineer will be placed in the operating record. They will certify that the closure plan has been followed, noting discrepancies along with the corrective actions undertaken. At the end of the post closure period, the individuala certifications will be compiled into a final document and forwarded to NCDEQ Division of Solid Waste Management. 5 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification Post-Closure Inspection Checklist Location: Date: Time: Weather: Completed By: Yes No I. Security Control Devices: Are security control devices in place and functioning?   Are all warning signs prominent and legible?   Are there any signs of unauthorized entry on the site?   Are there signs of illegal dumping on site?   II. Final Cover System: Is the final cover free of erosion and depressions?   Is there leachate seeping from the final cover? (If yes, make note of location on comment section below.)   Is the vegetative cover continuous and in good condition, free of bare spots?   Does the site require mowing? (If yes, mow grass and note in comment section below.)   Is there ponding of water on final cover system?   III. Groundwater Monitoring Wells: Is the casing upright and unobstructed?   Is the outer casing secure and locked?   Is the ID tag present and legible?   IV. Miscellaneous: Are all benchmarks visible and intact?   Are all ditches free of debris and litter?   Are any odors present which may indicate landfill gas migration?   6 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification COMMENTS Please use the section below to comment on any area not covered above and also to note any areas of concern or needing immediate attention. 7 Water Quality Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents Contents Purpose and Intent ..................................................................................................................... 1 Background ................................................................................................................................ 1 Hydrogeologic Setting ............................................................................................................ 2 Water Quality Monitoring Program for Unit 1 .......................................................................... 5 Proposed Water Quality Monitoring Plan.................................................................................... 5 Sampling Locations ................................................................................................................ 6 Data Collection ....................................................................................................................... 7 Well Construction ..................................................................................................................11 Analytical Procedures ............................................................................................................11 Tables Table 1 Summary of Monitoring Sample Locations and Functions ...........................................10 Table 2 Monitoring Network Well Construction Details .............................................................11 Table 3 Updated MNA Monitoring Parameters and Methods ....................................................12 i City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Purpose and Intent Purpose and Intent The purpose of this Revised Water Quality Monitoring Plan (Plan) is to provide a program for the collection and evaluation of groundwater, surface water and leachate samples at Unit 1 of the Hanes Mill Road Municipal Solid Waste Landfill (Landfill). The Plan describes the monitoring program for both the Subtitle D area and the unlined landfill area of Unit 1. This program evaluates samples from groundwater wells installed in the uppermost aquifer, as well as surface water, and leachate from the leachate collection system. Implementation of this plan will provide efficient and effective early detection of any release of hazardous constituents to the uppermost aquifer, so as to be protective of public health and the environment as well as evaluate the efficacy of ongoing corrective actions. As the waste mass continues to stabilize and remediation progresses, it is anticipated that the monitoring program will need to be periodically adjusted. As the groundwater remediation model continues to be validated over time, fewer confirmatory groundwater samples will be required. This Plan was prepared in accordance with North Carolina Solid Waste Management Rules 15A NCAC 13B, Sections .1630 through .1637 under the guidance of a North Carolina licensed geologist. Background The Landfill is located at the intersection of US Highway 52, Hanes Mill Road, and Ziglar Road and is owned and operated by the Winston-Salem/Forsyth County Utility Commission (Commission) under North Carolina Permit No. 34-02. Unit 1 of the Landfill is composed of an unlined portion (now closed) and a Subtitle D lined portion (aka the “piggyback”). Unit 1 ceased receiving waste in August 2005 and the Commission is now disposing of waste in the Expansion Landfill. The Expansion Landfill is not addressed in this section. The Commission conducted routine detection groundwater monitoring (Appendix I constituent list, per Rule 15A NCAC 13B .1633) for the unlined landfill until 1995. In 1995 and 1996, an assessment groundwater monitoring program (Rule 15A NCAC 13B.1634) was initiated due to exceedances of the North Carolina Groundwater Quality Standards (15A NCAC 2L, .0202). This assessment demonstrated that all impacts were limited in extent and confined to the facility’s property. The exceedances occurred in two monitoring wells located approximately 50 feet from the edge of the waste and resulted mainly from two sources of Volatile Organic Compounds (VOCs): primarily chlorinated solvents and their breakdown products and secondarily, benzene, toluene, and ethylbenzene – constituents found in petroleum products. An Assessment of Corrective Measures (ACM) was conducted and, based on the results, monitored natural attenuation (MNA) was selected as the most appropriate and cost-effective of the remedial options for the cleanup of the dissolved VOCs at the Landfill. This ACM was approved by the North Carolina Department of Environment and Natural Resources (NCDENR) in a letter dated March 24, 2005 (Gamble to McHargue). MNA involves collecting and evaluating data to document that the processes of natural attenuation are continuing to occur and are effective in meeting the remedial objectives. The Corrective Action Plan (CAP) to conduct MNA 1 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background at the Landfill was prepared and approved by NCDENR. Baseline MNA monitoring was completed and an assessment was detailed in the Springspring 2008 Semiannual Report. In response, NCDENR approved the request to remove four OW wells from the MNA monitoring on September 22, 2008 (including OW-6, OW-7DA, OW-11, and OW-13D). In accordance with the request from NCDENR, the addendum to the CAP was submitted to include additional corrective action measures and to revise the MNA monitoring plan. In the addendum, one background well (MW-1RR) and six down gradient wells (OW-3, OW-4, OW-10D, OW-12, OW- 14, and OW-17D) are included in the continuing MNA monitoring program which includes testing of Appendix II parameters. In a letter dated March 4, 2010 (Drummond to McHargue), NCDENR approved a request for a modification to reduce Appendix II groundwater monitoring to every other spring monitoring event at the closed unlined landfill beginning in 2011. As requested by NCDENR four independent samples were collected at the wells monitoring the closed unlined landfill (including the subtitle D cell) for detected Appendix II parameters to establish background groundwater concentration. Hydrogeologic Setting The Landfill is located in the southern Piedmont physiographic province of North Carolina. The physiography of the Piedmont is characterized by gentle to rough sloping terrain that becomes increasingly sloped closer to the mountains and is dissected by a well-developed drainage system. The topography is developed on deeply weathered, belted metamorphic and igneous rocks that generally date from late Precambrian to Paleozoic Era. According to the soil survey of Forsyth County, North Carolina, prepared by the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) (1976), the surficial soils at the Landfill belong to the Pacolet-Cecil association. These soils are characteristic of Piedmont uplands where well-drained soils with a loamy surface layer and a clayey subsoil layer are found predominantly on gently sloping to sloping land. The Landfill is dominated by three main soil series as shown on Sheets 9, 10, 15, and 16 of the survey. These include the Hiwassee series, the Pacolet series, and the Madison series. A fourth series (Chewacla series), found outside of the footprint of the proposed landfill unit(s), is present along the floodplain of Grassy Creek. According to the geologic map of the east half of the Winston-Salem Quadrangle, North Carolina-Virginia, compiled by Espenshade and others, 1975; the geologic units identified at or adjacent to the Landfill include the following: pCag-Ashe Formation, pCaa-Ashe Formation, bc- Charlotte Belt rocks, and qgc-Charlotte Belt rocks. Nearly all of the Landfill property is underlain by typical Ashe Formation lithologies. Field checks of the local geology confirm this conclusion. The lithologic protoliths include turbidite facies (the bulk of the formation) and basalt flows (the amphibolite facies). The Ashe Formation is estimated to be 12 to 15 kilometers in thickness (Rankin, D.W., 1970). The main surface water drainage features of the Landfill are the two tributaries of Grassy Creek to the north and south of the property, and Grassy Creek itself to the west. Surface water drainage from the area of the existing Landfill is controlled through a series of catch basins and sediment ponds. Some surface water drains from the Landfill area into both the north and south 2 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background streams, which then carry it to Grassy Creek via culverts beneath the Norfolk Southern railway at the west edge of the Landfill. Other surface water flows directly from the Landfill area to Grassy Creek via two culverts located between the north and south streams. The 100-year floodplain of Grassy Creek is located between 150 and 300 feet west of the Landfill at a topographic elevation between 800 and 805 feet msl. Since both of the bounding streams are perennial, they are also areas of groundwater discharge at the Landfill. Groundwater flow for this portion of the Landfill property is primarily west towards Grassy Creek, with minor components of groundwater flow towards two bounding streams named North Branch Creek (NBC) and South Branch Creek (SBC). Groundwater in the Piedmont occurs both intergranularly in the weathered saprolite and within fractures in the bedrock. Typically, the water table is within the saprolite, and water supply wells are completed in bedrock. Total porosity in saprolite is generally relatively high with measured values as high as 40 to 50 percent. In bedrock, porosity is normally only 3 to 5 percent, but fractures are often well connected and hydraulic conductivity is comparable to or higher than that found in the saprolite. As the saprolite and bedrock are hydraulically connected, the contrast between porosities allows the saprolite to act as a groundwater reservoir for wells that pump from the bedrock. Sustained well yields for well-constructed bedrock wells in the Piedmont average from approximately 15 to 30 gallons per minute (Charles C. Daniel, III and R.A. Payne, 1990). The water table in the Piedmont, under natural conditions, is a subdued image of the surface topography. Recharge takes place on interfluvial areas, then travels downward and laterally to discharge along creeks and rivers. Thus, the vertical component of groundwater flow is directed downward in interfluvial recharge areas, comprising approximately 80 to 90 percent of land surface, and then has an upward component of flow as groundwater moves to discharge areas at streams. The groundwater at the Landfill flows from the highland recharge area northeast of the Landfill toward Grassy Creek located west of the Landfill. Minor components of groundwater flow may also occur radially from the crest of the Landfill toward the drainage features to the north and south. Based upon several slug tests performed on selected wells and piezometers in the study area, the hydraulic conductivity of the uppermost limits of the saprolite aquifer is 1.61 feet per day (ft/day), while the hydraulic conductivity of the partially weathered rock (PWR) unit of the aquifer ranges from 0.78 to 5.77 ft/day. The upper limits of the fractured bedrock range in hydraulic conductivity from 1.40 to 3.77 ft/day. A groundwater flow velocity was calculated for each well location using a variation of Darcy’s Law. Employing the average hydraulic conductivity values for the saprolite/PWR and bedrock units, an estimated groundwater flow velocity was calculated for the well locations along the eastern side of Grassy Creek and the southern side of SBC. Assuming an effective porosity of 20 percent (0.20) for saprolite and PWR wells and 5 percent (0.05) for rock wells, with calculated hydraulic gradients associated with the vicinity of each of these monitoring wells, a groundwater flow (pore water seepage) velocity was calculated for the study area. 3 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background The calculated seepage velocity for the saprolitic portion (including the PWR unit) of the uppermost aquifer in the vicinity of the assessment wells along the eastern side of Grassy Creek ranges from 0.014 to 0.305 ft/day, while the estimated groundwater flow rate of the upper limits of the fractured bedrock portion of the aquifer averaged slightly higher at 0.829 ft/day. Site Hydrogeologic History The following is a brief history of the sites monitoring wells and hydrogeologic findings from them. Vertical gradients between the saprolitic portion of the aquifer and the upper limits of fractured bedrock exhibit a downward component of flow, specifically at OW-7/7M, OW-7/7D, OW- 11/11M, and OW-12/12M. This downward gradient averages 0.004 feet per foot (ft/ft). On the other hand, there are strong upward vertical gradients measured in most of the deeper groundwater assessment wells completed within fractured bedrock. At the southern end of the plume, a downward gradient (at 0.001 ft/ft) is indicated between OW-7, completed within the saprolite, and OW-7D, completed within the upper limits of fractured bedrock. However, a strong upward gradient is present within the fractured bedrock. This can be seen by the gradients between the saprolite (OW-7) and the fractured bedrock at OW-7DA. An upward gradient of 0.004 ft/ft is measured from a depth between 111 and 114 feet bls, between OW-7 and OW- 7DA. Likewise, a strong upward gradient was also measured between 47 and 114 feet bls at OW-7D and OW-7DA at 0.007 ft/ft. At the center of the area of groundwater impacts, a strong upward gradient exists between the saprolite (OW-9) and the upper limits of fractured bedrock (at 65 feet bls) in OW-9D. Here, a gradient of 0.010 ft/ft was measured. This upward gradient becomes stronger with depth, increasing to 0.032 ft/ft between OW-9 and OW-9DA, completed to 85 feet bls in fractured bedrock. In OW-13D, completed to 115 feet bls, the upward gradient increases to 0.038 ft/ft. Furthermore, the upward vertical gradient within the fractured bedrock itself is also strong. A gradient of 0.066 ft/ft is measured between 65 and 115 feet bls within fractured bedrock at OW- 9D/13D, and a stronger gradient is even measured between 85 and 115 feet bls at 0.106 ft/ft at OW-9DA/13D. Gradients on the northern end of the area of impacts also exhibit similar patterns. There is an upward vertical gradient between the saprolite at OW-10 and the PWR zone at OW-10M. This gradient increases between OW-10 and OW-10D and is completed within the upper limits of fractured bedrock. A gradient of 0.008 ft/ft is measured between OW-10 and OW-10D. Beyond the small area of groundwater impacts to the north and south, nearly identical vertical gradients exist between the saprolite and PWR units, with 0.004 ft/ft downward at OW-11/11M and 0.003 ft/ft downward at OW-12/12M. As presented in the ACM, a rose diagram was produced using a fracture trace analysis of the straight-line segments of streams and tributary valleys. The resulting rose diagram shows a wide range of straight-line valley segment orientations. The strongest peak occurs at an orientation of between north 30 and 40 degrees east. Subsidiary peak orientations are located at north to north 10 degrees west, north 30 to 40 degrees west, and west to north 80 degrees west. The strongest null, at north 50 to 60 degrees west, is perpendicular to the strongest peak. 4 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan While fracture orientation is certainly important to groundwater flow in solid bedrock, the primary occurrence of shallow groundwater in the Piedmont is within the saprolite overlying bedrock. Here, groundwater flow occurs intergranularly, as compared to the flow of groundwater along fractures in bedrock. In this textural environment, the orientation of platey minerals, particularly micas that define foliation in the predecessor rock, has a stronger effect on groundwater flow than highly altered fracture remnants found in the saprolite. Considering this reality, a preliminary measurement of the orientation of remnant foliation has been made in the Landfill area. In the area where active soil cutting is taking place and where erosion has occurred along runoff channels, foliation and rare granitic veins or pegmatites are evident. Most of the observed foliation strikes between north and north 30 degrees east, and dips at about 20 to 60 degrees to the west. These strikes are subparallel to the dominant orientation of straight segments found in the vicinity. Water Quality Monitoring Program for Unit 1 Water quality at Unit 1 of the Landfill is monitored in accordance with the approved Revised Groundwater Monitoring Plan, dated March 1996, as modified by verbal and written communications between the City of Winston-Salem (City) and the NCDENR. Samples are collected from the following locations and analyzed in accordance with state approved laboratory methods. • Site Background Well – MW-1RR; • Closed Unlined Landfill – Performance wells (OW-3, OW-4, OW-10D, OW-12, OW-14D, and OW-17D), compliance wells (OW-6, OW-7DA, OW-10D, OW-11, and OW-12, OW- 13D), and two observation wells (OW-14D and OW-17D); • Subtitle D (“Piggyback”) Landfill – MW-6, MW-6D, MW-7, MW-8, MW-9, and MW-11. • Four surface water locations – NBC-1, NBC-2, SW-3, and SW-4. • One leachate sample. The updated water quality monitoring plan incorporates those changes previously approved by DENR at the Closed Unlined Landfill. These changes consist of (1) revising the monitoring parameters and Appendix II frequency; and (2) including the background well (MW-1RR) into the performance monitoring network at the Closed Unlined Landfill. Also, in accordance with NCDENR’s request, OW-7D will be sampled in the next semiannual sampling event. The sampling data will provide supplemental information in regards to the monitored natural attenuation status. Proposed Water Quality Monitoring Plan The proposed water quality monitoring program for Unit 1 of the Landfill includes select detection and assessment wells, four surface water sampling locations and one leachate collection point. The monitoring plan has been updated in accordance with the NCDENR letter of September 22, 2008 and March 4, 2010. The Plan update includes sample locations (groundwater, surface water and leachate), sample frequency, sample collection; preservation shipment; analytical procedures; chain of custody control; quality assurance and quality control. These components are designed to ensure monitoring results that provide an accurate 5 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan representation of water quality at the Landfill through effective detection monitoring and assessment of the efficacy of the MNA program. Sampling Locations The following paragraphs present the general rationale used to select groundwater (both detection and corrective action performance monitoring systems), surface water, and leachate sample locations. A substantial amount of geologic and hydrogeologic data has been developed at this site, much of which has been summarized in the Landfill permit documents. Well locations have been selected on the basis to provide water quality data from the uppermost aquifer beneath the facility, either in the unconsolidated saprolitic portion of the aquifer, as is the case for the Subtitle D Landfill, or from the fractured bedrock aquifer. The hydrogeologic and geologic characteristics of the facility and surrounding land, and the quantity, quality, and direction of groundwater flow were evaluated to determine the appropriate selection of monitoring wells. This evaluation considered site specific hydrogeologic information including aquifer thickness, groundwater flow rate, and groundwater flow direction, including seasonal and temporal fluctuations in groundwater flow. Also considered were unsaturated and saturated geologic units (including fill materials) overlying and comprising the uppermost aquifer; including but not limited to: thicknesses, stratigraphy, lithology, hydraulic conductivities, porosities and effective porosities, lithology of the aquifer and unsaturated zone; hydraulic conductivity of the aquifer and unsaturated zone; groundwater flow rates; minimum distance of travel; resource value of the aquifer; and nature, fate, and transport of any detected constituents. In addition, the distance of each proposed well relative to the waste unit (less than 250 feet) and the boundary of the property (50 feet or greater) was considered. Background Well Using the historical water table elevation data collected during multiple groundwater monitoring events at the facility, a background well was selected on the basis of hydraulic position in relation to the solid waste management units. The background well, MW-1RR, is hydraulically "upgradient" of the units and is located near former background monitoring wells OW-1 and OW-2. Historical and current water table elevation data indicates this well is consistently in an upgradient position. As discussed in detail as part of the Design Hydrogeologic Report, the uppermost aquifer at the Landfill is the saprolite derived from weathering of Ashe Formation rocks. The background well is completed in this uppermost aquifer, with a well screen that spans the water table, per North Carolina Department of Environment and Natural Resources. Please see Figure 1 for the locations of the background wells. Groundwater Monitoring Wells The proposed groundwater monitoring network for the Subtitle D cell includes background well MW-1RR and six side gradient or downgradient wells (MW-6, MW-6D, MW-7, MW-8, MW-9, MW-11). The proposed groundwater monitoring network for the unlined cell includes one background well (MW-1RR), and six performance wells (OW-3, OW-4, OW-10D, OW-12, OW- 14D, and OW-17D). and eight four complianceassessment wells (OW-3, OW-4, OW-6, OW- 6 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan 7DA, OW-10D, OW-11, OW-12, and OW-13D) . In addition, two observation wells (OW-14D and OW-17D) , located on the floodplain of Grassy Creek, are to be monitored as sentinel wells (Figure 1). Surface Water Monitoring Points Samples will be collected from four surface water sample locations (NBC-1, NBC-2, SW-3, and SW-4) to monitor the quality of surface water on the Landfill property. SW-3 and SW-4 are located along South Branch Creek. A surface water sample representing background water quality along the northern side of the Landfill will be collected from the upstream end of North Branch Creek at NBC-1. A downstream surface water sample, NBC-2, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. Likewise, a surface water sample representing background water quality along the southern side of the Landfill will be collected from the upstream end of South Branch Creek at SW-3. Finally, a downstream surface water sample, SW-4, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. The location of these surface water sampling locations can be seen on Figure 1. Leachate Sampling Locations Leachate samples will be collected for analysis to determine the concentration of constituents released from the waste (if any). One leachate sample will be collected from the tanks. Leachate from the cells in Unit 1 is combined in this location before being pumped to the tanks where it is held until its release to the local treatment plant. The leachate sample will be analyzed for BOD, COD, temperature, conductivity, phosphate, pH, ammonia, Total Suspended Solids, sulfates, nitrates, mercury and Appendix I parameters. Summary The Subtitle D landfill monitoring wells, the surface water locations, and the background well will remain unchanged in location and analytical parameters from the previous monitoring program. The current monitoring program including these locations is performing properly. Table 3-1 summarizes the location, sampling type, parameters, and basic monitoring function for each of the sampling locations included in this Plan and presents a new set of groundwater wells associated with the closed, unlined portion of the Landfill Unit 1. Based on the extent of the property owned by the Commission, the rate at which groundwater flows, and the stable nature of the groundwater impacts, data gathered from these locations will adequately monitor the facility and track the status of groundwater remediation. The physical location of each sampling site is identified on Figure 1. Data Collection A brief description of the sampling frequency, monitoring functions, and types of data that will be collected and analyzed during the performance of this Plan is provided in this section. Analytical Parameters and Frequency The analytical parameters for groundwater at the detection wells, surface water, and leachate samples associated with the Subtitle D cell will be consistent with the historical monitoring and 7 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan are unchanged except as described below. Monitoring wells at the lined landfill have been sampled for Appendix II parameters for four events due to detection of 1,1-DCE above the 2L Standard at MW-8. NCDENR has requested two additional consecutive events must be completed for each well with no groundwater standard exceedances before the site can revert to detection monitoring. The parameters for the MNA performance monitoring program have been slightly adjusted to reduce the performance monitoring parameters or the frequency of monitoring for the parameters in accordance with the NCDEDR letters of September 22, 2008 and March 4, 2010. The updated monitoring parameters will include Appendix II parameters, field parameters and laboratory parameters (Table 3-3). Performance monitoring includes analysis for Appendix II parameters at the closed unlined landfill which is conducted once every 2 years during the spring semiannual monitoring event. The two year frequency for Appendix II testing is in accordance with the NCDEDR letter dated March 4, 2010. Table 3-1 shows the frequency of monitoring at each well. This frequency will be sufficient to provide detection and performance monitoring considering: a. The extensive amount of down gradient property owned by the County; b. The existing impacts are limited to low level concentrations of VOC’sVOCs; and c. The incorporation of additional parameters into the monitoring program (e.g. chloride, sulfate, dissolved oxygen, ORP and methane gas – which are indicators of the source contributor and geochemical indicators of natural attenuation). Groundwater Level Measurements During each required water quality sampling event, static groundwater levels (and total well depth) will be obtained from the proposed groundwater compliance monitoring wells immediately prior to purging. An electronic water level meter capable of measuring differences in water levels of 0.01 feet will be used to obtain these measurements. All measurements will be obtained from a reference point at the top of each PVC well casing which has an elevation established by a North Carolina registered land surveyor. The horizontal position of each well will be established using North Carolina Plane Coordinates. These data will be used to calculate the volume of standing water in each well and will provide information concerning well integrity (e.g., identify the presence of excessive siltation and casing breaches). All measuring equipment will be decontaminated before use at each well as established by Environmental Protection Agency (EPA) standards. Groundwater Direction and Flow Measurements Groundwater elevations will be calculated for each monitoring well using surveyed top-of-casing elevations prepared by a North Carolina registered land surveyor. Calculated potentiometric surface elevations for each sampling event will be placed on a scaled base map of the facility beside each respective monitoring point and contoured to produce a water table potentiometric surface map depicting potential groundwater flow direction(s) across the site. In addition, the estimated groundwater flow velocity will be calculated for each water quality sampling event. Using the static water table potentiometric data, effective porosities, hydraulic 8 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan conductivity determined from slug tests, and the calculated hydraulic gradients for the respective sampling event, an estimated seepage (pore water) velocity will be calculated to continue to assess the potential for the migration of the low concentrations of VOC’sVOCs. 9 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 1 Summary of Monitoring Sample Locations and Functions Sample ID Location Sample Type Area Monitored Parameters Analyzed Monitoring Function Spring Event Fall Event Current Proposed Ground-water Surface Water Leachate Closed Subtitle D Closed Unlined Appendix MNA(3) Appendix Background Data Release Detection Performance Monitoring I II I II MW-1RR X X X X X(21) X X X X MW-6 X X X X X X(1) X MW-6D X X X X X X(1) X MW-7 X X X X X X(1) X MW-8 X X X X X X(1) X MW-9 X X X X X X(1) X MW-11 X X X X X X(1) X OW-3 X X X X X(21) X X X X OW-4 X X X X X(21) X X X X OW-6 X X X X X(2) X X X OW-7DA X X X X X(2) X X X OW-10D X X X X X(21) X X X X OW-11 X X X X X(2) X X X OW-12 X X X X X(21) X X X X OW-13D X X X X X(2) X X X OW-14D X X X X X(21) X X X X OW-17D X X X X X(21) X X X X NBC-1 X X X X NBC-2 X X X X SW-3 X X X X SW-4 X X X X Leachate Tank X X X X4 X (1) Appendix II monitoring for the closed Subtitle D site begins in Fall 2011 after the completion of background sampling for assessment monitoring (21) Samples will be monitored for Appendix II constituents every other spring monitoring event beginning in spring 2011. Detected Appendix II parameters will be monitored independently for 4 events at all wells at the unlined landfill. (32) Detail for performance monitoring is listed in Table 3-3. (43) Additional leachate parameters include BOD, COD, nitrate, sulfate, phosphate, TSS, ammonia and mercury. 10 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Well Construction Each downgradient well is installed with a screened interval of Schedule 40 PVC well screen with a 0.01-inch slotted opening. The construction of the groundwater monitoring wells is in general accordance with the North Carolina Well Construction Standards. Table 3-2 presents groundwater monitor well construction details. A schematic showing well-specific construction details for each well is provided in the Appendix of this Plan. Table 2 Monitoring Network Well Construction Details Well Grade Top of Casing Well Depth Screened Interval Screened Elevation Spring 2010 Water Levels (FT MSL) (FT MSL) (FT BLS) (FT MSL) Depth TOC FT MSL MW-1RR 893.60 896.82 60.0 45.0 - 60.0 848.6 - 833.6 41.08 855.74 MW-6 865.60 867.78 35.0 20.0 - 35.0 845.6 - 830.6 26.84 840.94 MW-6D 865.60 867.89 64.5 54.5 - 64.5 811.1 - 801.1 27.32 840.57 MW-7 843.10 845.33 25.0 10.0 - 25.0 833.1 - 818.1 14.88 830.45 MW-8 833.80 836.91 20.0 5.0 - 20.0 828.8 - 813.8 10.25 826.66 MW-9 840.40 842.31 30.0 15.0 - 30.0 825.4 - 810.4 20.58 821.73 MW-11 843.20 845.23 30.0 15.0 - 30.0 828.2 - 813.2 17.85 827.38 OW-3 817.75 820.13 16.0 6.0 - 16.0 811.8 - 801.8 8.53 811.60 OW-4 806.83 809.37 16.0 6.0 - 16.0 800.8 - 790.8 5.52 803.85 OW-6 824.74 827.12 27.0 12.0 - 27.0 812.7 - 797.7 16.28 810.84 OW-7DA 798.80 801.52 115.0 110.0 - 115.0 688.8 - 683.8 4.44 797.08 OW-10D 817.30 820.09 80.0 75.0 - 80.0 742.3 - 737.3 18.14 801.95 OW-11 804.47 806.69 16.0 6.0 - 16.0 798.5 - 788.5 2.68 804.01 OW-12 798.40 800.14 15.0 5.0 - 15.0 793.4 - 783.4 3.88 796.26 OW-13D 803.80 806.41 115.0 110.0 - 115.0 693.8 - 688.8 4.64 801.77 OW-14D 801.20 803.95 80.0 70.0 - 80.0 731.2 - 721.2 3.03 800.92 OW-17D 798.80 801.54 80.0 70.0 - 80.0 728.8 - 718.8 4.53 796.87 FT – Feet MSL – Mean Sea Level BLS – Below Land Surface TOC – Top of Casing Analytical Procedures Test Parameters and Methods Low-flow purging and sampling techniques are the preferred methodology for purging and sampling monitoring wells. Dedicated pumps will be utilized where available and otherwise decontaminated peristaltic or bladder pumps will be utilized. The pump will be positioned within the screened interval and will be pumped at such a rate that minimal drawdown will occur in the well. This is usually between 100 and 500 milliliters per minute (ml/min). 11 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 3 Updated MNA Monitoring Parameters and Methods Parameter Method or Equipment Used Monitoring Frequency Field Parameter Measurements Temperature Water quality meter Semiannual pH Water quality meter Semiannual Conductivity Water quality meter Semiannual Oxidation Reduction Potential (ORP) Water quality meter Semiannual Dissolved Oxygen (DO) Downhole or flow through cell meter Semiannual Turbidity turbidity meter Semiannual Water Elevation Electronic Water Level Indicator Semiannual Ferrous Iron SM 3500-Fe or Field Meter Semiannual Laboratory Analysis Hydrogen, sulfide, alkalinity, and volatile fatty acids Every 5 years from fall 2006 Methane, ethane, and ethane Every 3 years from fall 2006 Appendix I VOCs EPA Method 8260 Semiannual Appendix I Metals Varies Semiannual Appendix II Parameters* Once Every Two Years Nitrate-N EPA 352.1/353.2/353.3 Semiannual Sulfate EPA 375.4/375.2/300.0 Semiannual Chloride EPA 325.2/325.3/310.0 Semiannual Total Organic Carbon SM 5310B/310.2 Semiannual Note: * Four independent samples will be analyzed for any detected Appendix II Parameter from all Performance wells to establish background levels for the compound Once drawdown has stabilized, a flow through cell meter will be connected to the water discharge outlet to record field measurements [pH, temperature, specific conductance, dissolved oxygen (DO), salinity, and oxidation reduction potential (ORP)] to determine when a representative sample can be collected. These measurements will be obtained from a field- calibrated instrument in accordance with the manufacturer’s specifications and industry standards. The flow cell meter will log the geochemical changes of the purge water and signal when they become stabilized. Well purging efforts will continue until the following stabilized conditions occur: pH ±0.2 units, DO ±0.2 mg/l (or ± 20% whichever is greater), specific conductance ±5%, ORP ±10 millivolts (note this compound is optional and is not required). At that time, the flow cell will be disconnected allowing the water quality samples to be collected directly from the discharge tube under low-flow conditions (<100 ml/min). The parameters to be incorporated into the MNA performance-monitoring program have been selected to track contaminant concentrations (including daughter products) and key indicators of natural attenuation processes, and detect any new potential impacts. 12 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Field measured parameters include pH, specific conductivity, temperature, dissolved oxygen (DO), and oxidation reduction potential (ORP) which serve as indicators of natural attenuation processes, as well as indicators of general water quality. Table 3-3 presents the performance monitoring parameters and methods. Sample Preservation and Shipment All samples will be collected using the containers, preservatives, and holding times appropriate for each respective parameter being analyzed. The proper chain of custody and sample blank (trip blank and equipment blank) procedures will also be followed accordingly. In addition to providing evidence of attenuation, data (groundwater elevation measurements) will be collected to determine the direction and rate of any contaminant migration. All samples will be analyzed for the targeted parameters by a laboratory certified by the State of North Carolina. Surface water samples will be collected according to the “Environmental Investigations Standard Operating Procedures and Quality Assurance Manual”, May 1996, Sections 5 and 10. Samples will be collected directly into the sample containers facing upstream at mid-depth at the center of the channel (except VOCs). Surface water samples for VOC analysis will be collected using decontaminated glass lab containers and transferred to 40 ml vials leaving no headspace. Care will be taken not to disturb the bottom sediment and not to displace the preservative from a pre-preserved sample container. The area of the surface water samples will be selected according to the location of the greatest degree of cross-sectional homogeneity. If available, the surface water sample locations will be selected immediately downstream of riffle areas to ensure good vertical mixing. Tributaries will be sampled as near the mouth as feasible. Temperature, pH, turbidity, and conductivity will be measured at each surface water sample location. Surface water samples will only be collected if flowing water is noted at the time of sampling (i.e. not stagnant water). Reporting The data from each semiannual sampling event will be evaluated and reported to the NCDENR NCDEQ along with the regular semiannual groundwater reports. At the end of a two-year period, the groundwater remediation status will be re-evaluated. 13 Landfill Gas Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Contents Introduction ................................................................................................................................ 1 Background Information ............................................................................................................. 2 General .................................................................................................................................. 2 Site Information ...................................................................................................................... 2 Landfill Gas Overview & Regulatory Action Levels ..................................................................... 3 Landfill Gas Monitoring .............................................................................................................. 4 Proposed Landfill Gas Monitoring Procedure.......................................................................... 4 Permanent Monitoring Station Design and Installation ........................................................ 4 Gas Migration Monitoring ...................................................................................................11 Reporting of Data and Record Keeping ..............................................................................17 Continuous Monitoring of On-Site Structures .....................................................................17 Schedule for Installation of Monitoring Elements ...................................................................17 Maintenance and Calibration of Monitoring Elements ............................................................18 Maintenance of Permanent Monitoring Stations .................................................................18 Calibration of Portable Monitoring Instruments ...................................................................18 Contingency Plan ......................................................................................................................19 Contingency Plan Guidelines .................................................................................................19 Contingency Plan - On-site Structures ...................................................................................19 Immediate Action ...............................................................................................................19 Action within 7 Days ...........................................................................................................20 Action within 60 Days .........................................................................................................20 Contingency Plan - Facility Property Boundary ......................................................................20 Immediate Action ...............................................................................................................20 Action within 7 Days ...........................................................................................................20 Action within 60 Days .........................................................................................................21 LFG Control System Installation and Monitoring .......................................................................23 Passive Gas Control System .................................................................................................23 Surface Monitoring and Observations ................................................................................23 Subsurface Pressure .........................................................................................................23 Proximity ............................................................................................................................23 Active Gas Control System ....................................................................................................24 Gas Collection System .......................................................................................................24 i City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Gas Utilization or Control System ......................................................................................24 Safety .......................................................................................................................................25 Tables Table 1 Compliance Levels for Methane ................................................................................... 3 Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ........................................... 4 Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 ........................................ 4 Table 4 Contingency Plan Contacts .........................................................................................19 Table 1 Compliance Levels for Methane ................................................................................... 3 Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ..........................................54 Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 .......................................54 Table 4 Contingency Plan Contacts ..................................................................................... 1513 Figures Figure 1 Drawing 00C-02 Gas Monitoring Wells ........................................................................ 6 Figure 2 Typical Methane Probe Construction..........................................................................10 Figure 3 Groundwater Surface Contour Map ............................................................................13 Figure 1 Drawing 00C-02 Gas Monitoring Wells ........................................................................65 Figure 2 Typical Methane Probe Construction...........................................................................87 Figure 3 Groundwater Surface Contour Map ........................................................................... 119 Appendices Appendix A - Field Data Form Appendix B – Boring Logs ii City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Introduction Introduction The purpose of this Landfill Gas Monitoring Plan (LGMP) is to provide a management practice for the monitoring and control of landfill gas generated by the Hanes Mill Road Landfill. Following approval of this LGMP by the North Carolina Department of Environmental Quality and Natural Resources (NCDEQ) Division of Waste Management (DWM), a routine methane monitoring program will be implemented at the landfill. Once final closure of the unitfacility is complete, the monitoring program will continue in accordance with NcNC regulation, 15A NCAC 13B .1627 (d). At the present time, this term is for a minimum of 30 years. Following approval, this plan will be placed in the landfill operating record and shall remain open for revisions throughout the active life of the landfill, as well as after landfill closure is complete. All changes to this plan will be submitted to NCDEQ DWM as they are implemented. 1 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Background Information Background Information General The Hanes Landfill is located off Hanes Mill Road approximately five miles north of the City of Winston-Salem, North Carolina (the City) and is operated under North Carolina NCDEQ DWM Permit No. 34-02.The facility consists of two major unitsareas: the original landfill unit consisting of the unlined and “piggyback” unitarea, which closed in 2005 is now closed, and an expansion area which is currently active. The closed landfill contains an unlined and a lined MSW unit and is located on approximately 181 acres. The landfill expansion area occupies approximately 90 acres to the west of Grassy Creek and the Norfolk Southern Railroad. Phase 1 of the expansion area was permitted, constructed, and begin accepting waste in May 2005. The proposed Phase 2 of the expansion area is located immediately north of Phase 1 and consists of approximately 22 acres. Filling at the landfill will be conducted by the area method in which the waste will be placed in lifts of approximately 10 feet in height which is then covered with soil (or approved alternative cover) on a daily basis. Site Information Land use is primarily limited to residential development to the north and west of the landfill expansion area. To the east of the area are the Norfolk Southern Railroad line, the closed landfill area, and a combination of commercial and residential developments. The headquarters for Sara-Lee Corporation is located along the southern edge of the landfill expansion area; land to the south is also being used for other commercial endeavors, as well as residential development. 2 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Overview & Regulatory Action Levels Landfill Gas Overview & Regulatory Action Levels One of the byproducts of landfilling municipal solid waste is landfill gas which is generated by the anaerobic decomposition of waste within the landfill. Landfill gas typically consists of methane (CH4) and carbon dioxide (CO2), with trace amounts of oxygen (O2), water (H2O), nitrogen (N2), hydrogen sulfide (H2S), and other gases. The amount and rate of generation of landfill gas is affected by several factors, including the following. • Total refuse tonnage in-place. • Moisture content of the refuse. • Age of the refuse. • Organic composition and pH value of the refuse. • Method and degree of compaction of the refuse. • Type and amount of cover material used. The concentration of the landfill gas varies according to site-specific conditions; however, landfill gas compositions of 30-53 percent methane (CH4) and 34-51 percent carbon dioxide (CO2) are common. In addition to being a potent greenhouse gas, tThe primary health and safety concern with landfill gas in the immediate area of the landfill is the explosive characteristic of methane. Methane concentrations in excess betweenof 5 and 15 percent by volume in air (5% is referred to as the “Lower Explosive Limit” or LEL, and 15% is referred to as the Upper Explosive Limit or UEL) are able to create an explosion hazard and can also propagate a flame, thus creating an explosion hazard. The Upper Explosive Limit (UEL) for methane is 15 percent by volume in air. Landfill gas can travel in all directions, taking the path of least resistance. Landfill gas moves from areas of higher concentrations to areas of lower concentrations (diffusion), or from higher gas pressure zones to lower gas pressure zones (convection). Subsurface geologic and hydrogeologic conditions contribute greatly to the potential for gas migration. When landfill gas migration is taking place, on-site and nearby structures are at risk of receiving migrating gas due to confined spaces in or under the buildings. Landfill gas can enter buildings through cracks in the foundation or subsurface utility services. Lack of ventilation may result in the buildup of methane concentrations to explosive limits. In an effort to eliminate the potential hazards associated with the migration of landfill gas, NCDEQ has promulgated regulations (15A NCAC 13B .1626 (4)) , which require owners and/or operators of all municipal solid waste landfill facilities (MSWLF) to monitor methane at the facility property boundary and on-site structures. Table 3-1 below provides the present regulatory limits for methane at MSWLF sites. Table 1 Compliance Levels for Methane Location Lower Explosive Limit (% LEL) Maximum Methane Concentration in Air Property Boundary 100% 5% Facility Structures 25% 1.25% 3 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Landfill Gas Monitoring Proposed Landfill Gas Monitoring Procedure To provide a means of monitoring methane gas at the landfill, permanent gas migration monitoring stations have been installed along the perimeter of the active and closed landfill areas. These stations are monitored on a quarterly basis. Additional stations will be installed in the Phase 2 expansion area as needed. Permanent Monitoring Station Design and Installation Permanent monitoring stations have been installed around the active and closed landfill. All the wells are for detection monitoring. Figure 1, Drawingdrawing 00C-02 Gas Management Plan, shows the monitoring wells at the landfill. ACTIVE LANDFILL EXISTING STATIONS Eight permanent monitoring stations (MM-1 through MM-8) have been installed along the permit boundary for Phase 1 of the landfill expansion at not more than 500-foot intervals (see Drawing C-8). Four Three additional wells will have been installed and a fourth is in the process of being installed for Phase 2 prior to waste placement. The well locations were placed between the permitted waste boundary and property lines. No wells are shown between the active landfill and Grassy Creek since this is interior to the property line and Grassy Creek acts as a cut-off feature. The following tables summarize the existing and proposed installation details for each gas probe. Figure 4-12 shows the typical construction details for a permanent methane monitoring probe. Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 Station ID Number Total Depth Screened Interval MM-1 7 Feet 3 - 7 Feet MM-2 14 Feet 2 - 14 Feet MM-3 14 Feet 2 - 14 Feet MM-4 2.5 Feet 1.5 - 2.5 Feet MM-5 4 Feet 2 - 4 Feet MM-6 5 Feet 2 - 5 Feet MM-7 5 Feet 2 - 5 Feet MM-8 4 Feet 2 - 5 Feet MM 9 7 Feet 2 – 7 Feet MM 10 10 Feet 2 – 10 Feet MM 11 40 Feet 2 – 40 Feet MM-12 To be installed Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 Station ID Number Total Depth Screened Interval MM-12 45 Feet 2 - 45 Feet Notes: (1) See boring logs for subsurface lithology (Appendix B) (2) See potentiometric surface map for depth to groundwater 4 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 5 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Replace this page with (11x17) Figure 1 Drawing 00C-02 Gas Monitoring Wells 6 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Formatted 7 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 8 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 9 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Figure 2 Typical Methane Probe Construction 10 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Station depths were based on geological formations logged during the installation of the nearest ground-water monitoring wells, the proposed depth of waste, and the recorded seasonal high ground-water elevations. All existing stations were installed with screens beginning at the elevation of the bottom of waste, or slightly above the top of the seasonal low water table (whichever is higher) and extending upward to approximately 2 feet below grade. Future monitoring stations will be installed using the same criteria. The final design depths of the future stations will be determined in the field during borehole installation. Refer to See the potentiometric map Figure 3, Groundwater Surface Contour Map, for the depth to groundwater. CLOSED LANDFILL EXISTING STATIONS Twenty-two permanent monitoring stations (MM-B through MM-K, MM-P through MM-U, MM-W through MM-Z, and MM-AA through MM-BB) have been installed along the boundary for the closed landfill. ACTIVE LANDFILL FUTURE STATIONS The gas monitoring stations for Phase 2 of the active landfill will be installed using 4.25-inch inside diameter (ID) hollow stem augers. Once at the desired depth, a 1-inch, Schedule 40 PVC gas probe will be inserted through the center of the augers. Each probe will be constructed with flush-threaded joints with a screened interval of 0.010-inch, factory-slotted well screen. Coarse- grained silica gravel will be placed around the screen interval by gravity settling. The gravel pack will extend to a minimum of 6 inches above the top of the screen. A 6-inch minimum bentonite seal will be placed immediately above the gravel pack. The remaining probe annulus will be sealed to surface grade using a Portland Type I cement mixture. Each probe station will be protected above grade by a 4-inch square steel locked well box secured in place with a 2- foot by 2-foot concrete pad. The top of each well probe will be fitted with a laboratory-type stop- cock valve for gas sample collection. The outside of each station will be fitted with an identification tag indicating the station number, installation date, driller name and registration, completion depth, and screened interval. Reading Gas Migration Monitoring Stations Reading of the permanent monitoring stations and on site structures will be conducted on a quarterly schedule. As per existing regulations, Tthe monitoring frequency of individual stations may be increased if methane is detected above the LEL. Sampling procedure will follow the manufacturer’s instructions. All perimeter gas stations shall be monitored for the following parameters. • Combustible Gas (methane) - with a Landtec GEM 2000 (or equivalent).The station shall be sufficiently evacuated with the sample pump so that methane concentrations are constant for at least 30 seconds. The large scale (0-100 percent methane-in-air) shall be used first. If readings are below 5 percent, the reading will be obtained using the smaller (0-5 percent methane-in-air) scale. Information from the monitoring will be recorded on the field data form (Appendix A). Any readings recorded at or above the LEL for methane will be immediately verified and reported as described in Section 5.0 of this plan. 11 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 12 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Replace this page with (11x17) Figure 3 Groundwater Surface Contour Map 13 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 14 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 15 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 16 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Reporting of Data and Record Keeping All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix A). Copies of the completed quarterly reports, including the original completed field data forms, will be kept on-site in the Landfill Operating Record for a minimum of two years. A separate calibration log for the on-site instrument will be kept on-site and will contain the following information. • Date and time of calibration. • Name of person calibrating. • Serial number and model number of instrument. • Type of calibration. • Results of calibration. Continuous Monitoring of On-Site Structures All Select on-site buildings will be equipped with a Sierra Monitor 2001 series (or equivalent) continuous monitoring device to detect combustible gas concentrations that may accumulate inside the structures. Continuous monitoring of the buildings may be supplemented with quarterly monitoring using a portable instrument. The Sierra Monitor 2001 series is rated to detect a wide range of combustible gases and has a methane detection range of 500 to 10,000 parts per million (ppm) (.05 to 1.0 percent methane- in-air). The monitor should be installed in an area of the structure where methane gas is most likely to accumulate. Any verifiable detection of methane in the structures will be addressed and reported in accordance with Section 5.0 of this LGMP. Reporting of Data and Record Keeping All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix A). Copies of the completed quarterly reports, including the original completed field data forms, will be kept on-site in the Landfill Operating Record for a minimum of two years. A separate calibration log for the on-site instrument will be kept on-site and will contain the following information. • Date and time of calibration. • Name of person calibrating. • Serial number and model number of instrument. • Type of calibration. • Results of calibration. Schedule for Installation of Monitoring Elements The permanent stations will be installed around Phase 2 of the active landfill after the City receives NCDEQ’s approval of this landfill gas management plan and before waste placement in Phase 2 of the active landfill. When the City determines that additional permanent monitoring stations are needed, this station will be installed and a notification will be submitted to the 17 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring NCDEQ DWM showing station design, location, and installation schedule. As-built documentation will be submitted to the NCDEQ DWM after installation. Maintenance and Calibration of Monitoring Elements The City conducts the following maintenance schedule and calibration procedures for the gas monitoring elements at the landfill. Training of personnel is conducted when necessary. Monitoring of the Phase 2 landfill area will be incorporated into this schedule. Maintenance of Permanent Monitoring Stations A visual inspection of the permanent stations will be conducted quarterly in conjunction with the monitoring events. The inspection schedule will increase with any increases in the monitoring schedule. The condition of following elements will be inspected. • Station label. • Protective casing and concrete pad. • Lock. • Station surroundings including standing water and vegetation. Any abnormalities regarding the condition of the station will be noted on the field log and immediately addressed. Calibration of Portable Monitoring Instruments CONTINUOUS MONITORING DEVICES Continuous monitoring devices will be maintained and calibrated according to the manufacturers’ recommendations. Maintenance and calibration will be conducted quarterly and will include the following tasks. • Verification of power to the monitor. • Ensuring that there is no interference of air flow to the monitor. • Exposing the sensor to a sample of calibration gas per the manufacturer's recommended procedure to verify that the monitor is calibrated correctly. PORTABLE MONITORING INSTRUMENTS Portable monitoring instruments such as the Landtec GEM 2000 will be maintained and calibrated according to the manufacturer's recommended procedure. For a detailed description of the maintenance and calibration procedures, the instruction manual should be consulted. 18 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Contingency Plan The City will implement the following contingency plan if the landfill gas readings at any monitoring location exceed the limits set by the stateregulations (see Section 3.0 of this plan). Contingency Plan Guidelines If allowable maximum limits for methane gas are exceeded at the facility property boundary or in on-site structures, the City will take the following steps. Step 1: Immediately take all necessary steps to ensure protection of human health and notify NCDEQ. Step 2: Within seven days of detection, place the methane gas levels detected and a description of the steps taken to protect human health in the operating record. Step 3: Within 60 days of detection, develop and implement a remediation plan that describes the nature and extent of the problem and proposed remedy for the methane gas releases, place a copy of the plan in the operating record and notify NCDEQ that the plan has been implemented. Consistent with the above requirements, notifications will be made either in person or by telephone followed by a facsimile transmission or letter. The City will also contact the following agencies or personnel as necessary. Table 4 Contingency Plan Contacts Agency or Personnel Contact Telephone Number City of Winston-Salem Solid Waste Administrator 336-727-7310 City of Winston-Salem Solid Waste Engineer 336-734-1506 399-5051 City of Winston-Salem Landfill Operation SuperintendentManager 336-399-5053430-6172 NCDEQ – Emergency Notification Environmental Specialist 336-771-5000776- 9672 Fire Department -- 336-727-800084 or 336-773-7900 Contingency Plan - On-site Structures The following contingency plan for responding to the detection of excessive methane gas quantities detected in all onsite buildings will be implemented by the City. Immediate Action • The affected building(s) would be vacated for a period of time determined by the appropriate emergency officials and all necessary steps will be taken to ensure protection of human health. • The landfill operations superintendentmanager, the occupants of the building(s), and the personnel listed in Section 5.1 will be contacted. • Notify NCDEQ. 19 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan • Following the evacuation, the building(s) will be monitored by City personnel to determine the extent and source of the methane. Remedial actions such as sealing cracks or connections would be taken as necessary. Action within 7 Days The landfill manager willstaff will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.2.1 of this LGMP. Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long term remedial action(s). IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the Plan has been implemented. Contingency Plan - Facility Property Boundary The City's proposed contingency plan for responding to excessive methane gas quantities at the facility property boundary is provided below. Immediate Action • Landfill personnel will be directed away from the affected area and all necessary steps will be taken to ensure protection of human health. • The affected area will be monitored daily for a period of time to confirm the methane concentration. • If monitoring reports are positive, areas adjacent to the affected zone (including the property line, utility trenches, and off-site buildings and structures) shall be monitored or screened by designated personnel. • If the methane gas quantities exceed the LEL at the facility boundary, the landfill manager and the personnel listed in Section 5.1 of this plan, may be contacted. • Notify NCDEQ. Action within 7 Days The landfill manager will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.3.1 of this LGMP. 20 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long-term remedial action(s) such as installation of passive or active gas control system. A copy of the LGMP will also be placed in the landfill operating record for the facility. NCDEQ will be notified that the remediation plan has been implemented. BAR-HOLE PROBE INSTALLATION AND MONITORING PROCEDURE Bar-hole probes may be temporarily installed as a remediation plan and monitored along the perimeter boundary of the landfill. Bar-hole probes may be used for identifying and tracking methane migration plumes, as described in Section 5.0, and as a substitute monitoring method for damaged or malfunctioning permanent probes. Prior to conducting bar-hole probing, the area will be checked for any subsurface utilities, conduits, or pipelines. If water or mud covers the desired probe location, then the probe will be offset to a nearby dry portion of the permit boundary or temporarily eliminated from the monitoring round. All precautions shall be taken to eliminate the introduction of moisture into the monitoring instrument. Any abnormalities in the probe location will be noted on the field data form (refer to Appendix A). The bar-hole procedure will involve pushing a 1/2-to 3/4-inch diameter metal rod a minimum of 2-3 feet into the subsurface soils. Upon removal of the metal rod, a probe connected to Landtec GEM 2000 or equivalent will be immediately inserted into the hole and sealed to minimize air infiltration into the sample. A measurement of the sample, along with other pertinent data, will be taken and recorded on the field data form located in Appendix A. Readings from the probe hole will be taken first with the instrument in the “HIGH” or 0-100 percent methane-in-air range. If a reading above 5 percent cannot be maintained during evacuation for at least 30 seconds, then the measurement shall be repeated with the instrument in the “LOW” or 0-5 percent methane-in-air (0-100 percent of the LEL) range. Upon completion of the monitoring, the probe hole will be backfilled with native soil. If concentrations of methane are measured at or above the LEL, additional bar-hole probes will be installed to assess the lateral extent of the migration. The additional probes will be placed in a radial pattern starting at the initial probe location and working in 5-foot increments outward. The pattern will continue until readings of 0 percent methane are obtained. Information from this monitoring procedure will be recorded on graph paper to determine the extent of the migration. The information will be submitted to NCDEQ in the Semiannual Ground-Water Monitoring Report. If it is determined that off-site migration exists above the LEL, the information, along with any proposed mitigation measures, will be submitted in accordance with Section 5.0 of this LGMP. 21 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan The bar-hole probe equipment will be maintained between monitoring events. Maintenance associated with the bar-hole probe monitoring includes ensuring plunger bar is clean and free of damage. IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the remediation plan has been implemented. 22 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring LFG Control System Installation and Monitoring If necessary, a gas control system can be installed as a mitigation measure to prevent the off- site migration of landfill gas. The City understands that the installation of an active gas collection system may be required at the landfill expansion area to control non-methane organic carbon (NMOC) emissions. Any active gas collection system required will be integrated into this LGMP after it is installed. The results of any landfill gas monitoring event, described in Section 4.0 of this LGMP, will be presented to NCDEQ for review. If a LFG control system is required at the landfill to control or prevent off-site gas migration, the City can pursue one of the following two alternatives. • Passive Gas Control System, or • Active Gas Control System. Passive Gas Control System Passive vents can release some of the pressure of landfill gas within the waste, thus reducing the amount of localized gas migration. A typical passive gas control system utilizes gas "vents" that are simple in design and require low maintenance. A passive gas control system has been proposed for implementation during the closure of the landfill. A passive gas control system consists of gas vents installed in the refuse. The passive vents will vent freely into the atmosphere, thereby reducing subsurface pressure and controlling local lateral migration of the gas. The vent wells should be designed and spaced so that the system could be converted into an active gas control system, if necessary, in the future (see Section 6.2). The locations of the passive vents are determined using any one, or a combination, of the following three methods. Surface Monitoring and Observations Observations of the surface conditions at the site can aid in determining the best location for passive vents. Venting cracks, stressed vegetation, and odors are all indicative of gas migrating through the soil cover. In addition, monitoring of the surface may be conducted to locate less visible emission sources. Subsurface Pressure If feasible, subsurface soil pressure measurements can be taken within the landfill permit limits to determine areas of increased pressure. Gas vents can then be installed to release the pressure. Proximity Passive vents should be installed in close proximity to the area of concern. One or more vents can be installed next to the permanent station, bar-hole probe, or facility structure that contained methane above the designated limits. Additional vents may be installed until the area of concern is mitigated. 23 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring The passive gas system performance monitoring is conducted on a quarterly basis and increased to a monthly basis if necessary. Monitoring methods are described in Section 4.0 of this Plan. Active Gas Control System An active gas control system consists of a collection system plus a utilization or control system. The design of the system components depends upon the site-specific conditions. The main components of an active gas collection system are the gas collection system and the gas utilization or control system. Gas Collection System The main components of a gas collection system are gas wells, gas collection headers with appropriate fittings and supports, and the moisture/condensate removal and collection system. It is anticipated that vertical wells will be used rather than horizontal wells. Horizontal wells require installation during filling, while vertical wells may be installed at any time. The locations of the vertical wells will be determined in a manner similar to locating the passive gas control vent system. Gas Utilization or Control System Two common types of gas utilization or control systems are LFG flare systems and cogeneration systems. Selection of the system will depend on several factors including LFG flow rates, quality, and cost-benefit analysis. Measurements will be performed to determine whether the methane can be economically collected and utilized as a fuel source. If economical, a cogeneration system may be installed. Typically, a cogeneration system includes a gas treatment plant, gas turbine(s) or internal combustion engine(s) and generating set(s), and other ancillary equipment. If the methane cannot be collected and utilized economically, a system consisting of multiple open gas flare units will be installed. A flare system will typically consist of gas blower(s), flares, moisture separators, and a detailed safety system. 24 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety Safety Prior to beginning a monitoring procedure, the landfill technician must understand the potential dangers associated with landfill gas. Not only is landfill gas explosive, it can also present the following other hazards. • Landfill gas may cause asphyxiation through oxygen displacement. Proper procedures must be followed when entering confined spaces which may be potential receptors of migrating landfill gas. • Some of the possible trace contaminants associated with landfill gas, such as hydrogen sulfide (H2S), are extremely toxic. Technicians must be trained in the indicators of H2S such as its recognizable odor (rotten egg) at low concentrations. At a minimum, the following items should be addressed by the technician, in addition to any site- specific safety procedures to reduce the chance of injury. • Be aware of the hazards of landfill gas as mentioned above. • Practice confined space entry procedures when entering structures that have been evacuated due to the possible presence of landfill gas in confined space. • Always practice the “buddy” system (i.e., work with a partner who remains outside of the area of possible exposure) when monitoring for landfill gas. • Know where all firefighting equipment (i.e., extinguishers, hoses, etc.) is stored and ensure that it is well maintained. • Determine whether additional personal safety equipment is necessary. • Do not smoke or allow others nearby to smoke while monitoring for landfill gas, or at any time when near landfill waste. • Know how the monitoring instruments work and how to operate and calibrate them properly. • Determine where all nearby subsurface utilities are prior to bar-hole probing. • Do not use odor as a primary indicator of landfill gas migration. • Inform the landfill manager or your supervisor of any possible hazards, no matter how small they may appear. 25 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety This page intentionally left blank. 26 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices A Appendix A - Field Data Form City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices B Appendix B – Boring Logs City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. Operations Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents Contents Introduction ................................................................................................................................ 1 Standard Operating Procedures ................................................................................................. 1 Waste Screening Programs ....................................................................................................... 1 Waste Receiving and Inspection............................................................................................. 1 Waste Determination Process ................................................................................................ 2 Prohibited Waste Types ......................................................................................................... 2 Hazardous Waste Contingency Plan ...................................................................................... 3 Waste Disposal .......................................................................................................................... 4 Placement of Initial Lift ........................................................................................................... 4 General Procedures ............................................................................................................... 4 Equipment Operations within the Landfill Cell ......................................................................... 5 Procedures for Stormwater Separation ................................................................................... 6 Alternative Daily Cover ............................................................................................................... 6 Concrete, Asphalt, and Brick Operations .................................................................................... 7 Explosive Gases Control ............................................................................................................ 8 Methane Monitoring Well Placement ...................................................................................... 8 Methane Monitoring Program ................................................................................................. 8 Sampling and Analysis Procedures ........................................................................................ 8 Emergency Response Plan .................................................................................................... 9 Sedimentation and Erosion Control ............................................................................................ 9 Leachate Management .............................................................................................................10 General .................................................................................................................................10 Leachate Pretreatment and Discharge ..................................................................................13 Separation of Stormwater ......................................................................................................13 Leachate Quality Sampling ....................................................................................................13 Leachate Contingency Plan ...................................................................................................13 Air Quality Control .....................................................................................................................14 Access and Safety Requirements .............................................................................................14 Spreading and Compacting Program ........................................................................................14 Record Keeping Program ..........................................................................................................15 i City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Introduction Introduction The purpose of this section is to identify protocols for the overall operation and maintenance of the landfill expansion area, which is owned and operated by the City. This plan has been prepared in accordance with appropriate NCDEQ .1600 rules and provides details of the procedures and policies, which shall be implemented throughout the life of the City’s landfill expansion area. Refer to tThe Phase 2 Application to Construct drawings for an illustrate illustration of the existing conditions of the landfill expansion (including known limits of existing and previous disposal areas, and buffer zones); the fill phasing (including the progression of operation including daily operation, transition contours, and final contours); and proposed final contours and erosion control plans (including storm water control, and stockpile and borrow operations). Standard Operating Procedures Hours and Days of Operation The landfill is open for operation between the hours of 7:00 AM and 4:30 PM, Monday through Friday, and from 8:00 AM to noon on Saturday. The landfill is normally closed on Sundays except where prior permission has been given to receive waste for special instances such as a natural disaster. The landfill is closed on Thanksgiving Day and Christmas Day. The landfill is open from 7:00 AM to 3:00 PM on New Year’s Day, Martin Luther King Jr. Day, Good Friday, Memorial Day, Independence Day, and Labor Day. It is anticipated that this schedule will continue, however operational hours and holidays may changes as the need arises. Waste Screening Programs In order to reduce the risk ofassure that prohibited wastes are not entering the landfill facility, waste screening programs have been implemented at the existing landfill. Waste received at both the scalehouse entrance and waste taken to the working face is inspected by trained personnel. These individuals have been trained to spot unauthorized waste, including: liquids, sludges, drums or barrels, and other banned wastes "chemical" odors. Programs for visual characteristics of prohibited wastes are an ongoing part of the existing landfill operation. These programs are implemented in accordance with Rule .1626 Part (1)(f)(4)(b). Waste Receiving and Inspection All vehicles must stop at the scalehouse located at the entrance of the landfill facility. Refuse transportation vehicles are weighed and the content of the load assessed. The scale attendant(s) requests from the driver of the vehicle entering the landfill a description of the waste it is carrying to ensure that unacceptable waste is not allowed into the landfill. The attendant(s) then visually checks the vehicle as it crosses the scale. Signs informing users of the acceptable and unacceptable types of waste are conspicuously posted on the landfill property. 1 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs The Hanes Mill Road Landfill also has a random waste inspection program. Vehicles under this program are selected at random. At least 1 percent of the waste stream (by weight) will be inspected under this program looking for liquid waste, hazardous waste, regulated PCB waste, and other banned items. Selected vehicles are directed to an area usually immediately adjacent to the working face where the vehicle will be unloaded. Wwaste is carefully spread using suitable equipment. An operator attendant trained to identify wastes that are unacceptable inspects the waste discharged at the screening site. If unacceptable waste is found, the load waste will be isolated and secured by coning off the areafor removal. Unacceptable wastes out of the permitted service area will be reported to the NCDEQ Division of Solid Waste Management within 24 hours of attempted disposal. of any waste the landfill is not permitted to receive. The hauler is responsible for removing unacceptable waste from the landfill property. If no unacceptable waste is found, the load will be pushed to the working face and incorporated with the daily waste. Sludges can be accepted at the active landfill, if the sludges pass the paint filter test and the hauler has documentation that the sludge is non-hazardous as defined by NC law. For each vehicle screened, a random waste screening inspection form will be filled out and will be kept on-site. The inspection form should include the following information. • The date and times wastes were received for inspection. • Source and type of wastes. • Vehicle and driver identification. • All observations made by the inspector. • Final disposition of waste after inspection. Waste Determination Process In accordance with 15A NCAC 13B .1626 (f), the Hanes Mill Road Landfill requires documentation and prior approval in order to dispose of special wastes such as contaminated soils, sludge, ash, sandblasting waste, and filter press residue, etc.. The main intent of the special waste program is to ensure that the landfill does not receive hazardous or liquid waste as defined by North Carolina law/regulations. Before special wastes can be disposed at the landfill, a Special Waste Disposal Application must be executed in its entirety, submitted to and reviewed/approved by the City-County Utility Solid Waste Administration. Approval for disposal must be obtained before attempting to dispose of special wastes. Prohibited Waste Types At the present time, Tthe following wastes are prohibited from disposal within the MSW landfill unit. • Whole scrap tires • Used oil • White goods 2 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs • Lead acid batteries • Yard trash • Regulated asbestos waste (friable) • Aluminum cans • Antifreeze • Beverage containers that are required to be recycled under G.S. 18B-1006.1 • Motor vehicle oil filters (after 10/1/2009) • Certain rigid plastic containers (after 10/1/2009) • Wooden pallets (after 10/1/2009) • Discarded computer equipment (after 1/1/2011) Does not include mice and keyboards • Certain Ttelevisions (after 1/1/2011) • Plastic bottlesOyster shells Although friable asbestos waste is prohibited, nonfriable asbestos waste such as shingles containing asbestos are accepted and treated as MSW. In the event that friable asbestos is delivered to the site, it will be treated as unacceptable waste and dealt with in a manner outlined in Section 5.3.3. In addition, operating criteria prohibit other materials from disposal at the MSW landfill unit. These criteria address the following types of waste. • Hazardous waste as defined by NC law. • Polychlorinated biphenyls (PCB) wastes as defined in 40 CFR 761. • Bulk or non-containerized liquid wastes unless the waste is household waste other than septic waste and waste oil; or the waste is leachate or gas condensate derived from the MSW landfill unit, whether it is a new or existing MSW landfill unit or lateral expansion, is designed with a composite liner and leachate collection system. • Containers holding liquid wastes unless the container is a small container similar in size to that normally found in household waste; the container is designed to hold liquids for use other than storage; or the waste is household waste. • Spoiled foods, animal carcasses, and other animal wastes fall into the category of special handling. The generator of the material should call in advance to the landfill, and a determination will be made as to whether or not the waste will be accepted. If the waste is approved, the generator will present the waste at a predetermined time, where an area for disposal will already have been prepared. The waste will be covered immediately. Hazardous Waste Contingency Plan In the event that unacceptable waste is detected at the landfill, appropriate equipment, protective equipment, personnel, and materials as necessary will be employed to isolate the wastes. The NCDEQ Division of Solid Waste Management will be notified immediately that an attempt was made to dispose of unacceptable waste that was generated outside the permitedpermitted Service Area at the landfill. If the vehicle attempting disposal of such waste is known, all attempts shall be made to prevent that vehicle from leaving the site or, if the vehicle 3 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal has left the site, immediate notice will be served on the owner of the vehicle that this hazardous unacceptable waste, for which they have responsibility, has been disposed of at the landfill. The landfill staff shall assist the Division of Solid Waste Management as necessary. If needed, the unacceptable waste will be covered with either on-site soils or other tarping material until such time when an appropriate method can be implemented to properly handle the waste. Should an incident where hazardous waste is found at the landfill occur, the event shall be documented as follows:. • Date and time of material detection. • Hauler name (company and driver). • Material(s) detected. • Material generator(s) if able to identify. • Action(s) taken to manage or return material(s). • Efforts taken if extreme toxicity or hazard was discovered. • Existing Landfill employee in responsible charge. Records of information gathered as part of the random waste inspection programs will be maintained at the landfill expansion during its active life and as long as required by regulation. Waste Disposal Placement of Initial Lift During solid waste placement operations, the landfill liner systems are most vulnerable during the placement of the first lift of solid waste. The first lift of MSW should be comprised of select loads spread on top of the operational cover above the leachate collection layer. These select loads must be free of long or large pieces of waste that may be pushed through the leachate collection layer and damage the liner. The first lift should be a minimum of 4 feet thick and provide sufficient area for at least one day’s operation without placing other areas of the liner in jeopardy. Another area of the liner system that is vulnerable during placement of the first lift of solid waste is the perimeter berms. The protective cover layer against the side wall will protect the liner system. As with the bottom liner, the first lift of MSW against the liner side walls should be comprised of select loads. In the event that the landfill supervisor identifies any damage to any part of the liner system, he should immediately affect its repair. Additionally, he should document the damage and the repair as a part of the operating record. General Procedures Solid waste transportation vehicles will arrive at the working face at random intervals. There may be a number of vehicles unloading waste at the same time, while other vehicles are waiting. In order to maintain control over the off-loading of waste, a certain number of vehicles 4 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal will be allowed on the working face at a time. The actual number will be determined by the traffic spotter. This procedure will be used in order to minimize the potential of off-loading non- acceptable waste and to control disposal activity. Operations at the working face will be conducted in a manner which will encourage the efficient movement of transportation vehicles to and from the working face, and to expedite the unloading of solid waste. This will all be performed in a safe manner. The approach to the working face will be maintained such that two or more vehicles may safely unload side by side. A vehicle turn-around area large enough to enable vehicles to arrive and turn around safely with reasonable speed will be provided adjacent to the unloading area. The vehicles will back to a vacant area near the working face to unload. Upon completion of the unloading operation, the transportation vehicles will immediately leave the working face area. Personnel will direct traffic as necessary to expedite safe movement of vehicles. Solid waste unloading at the active landfill will be controlled to prevent disposal in locations other than those specified by site management. Such control will also be used to confine the working face to a minimum width, yet allow safe and efficient operations. The width and length of the working face will be maintained as small as practical in order to maintain the appearance of the site, control windblown waste, improve operational efficiency, and, when necessary, minimize amount of cover soil required each day. Normally, two working faces will be active on any given day, with all deposited waste in other areas covered by either daily, intermediate, or final cover, as appropriate. The procedures for placement and compaction of solid waste include: unloading of trucks, spreading of waste into 2-foot lifts, compaction on relatively flat slopes using a landfill compactor and a minimum number of three full passes. Uses of portable signs with directional arrows and portable traffic barricades will facilitate the unloading of wastes to the designated disposal locations. These signs and/or barricades may be placed along the access route to the working face of the landfill or other designated disposal areas which may be established. Equipment Operations within the Landfill Cell Both the facilities operational vehicles and solid waste transportation vehicles must be restricted as follows within the landfill cells. • Equipment operation directly on the operational cover above the leachate collection layer shall be limited to rubber-tired vehicles having a maximum ground contact, (i.e., tire low ground pressure, of less than 32 psi.) • A minimum vertical separation of 3 feet shall be maintained between the geomembrane liner and all solid waste transportation vehicles. • A minimum vertical separation of 5 feet shall be maintained between the geomembrane liner and trash compactors or tracked operational vehicles. The operation of vehicles within those portions of the cell not actively receiving waste should be restricted to activities associated with sedimentation and erosion control. Comment [c1]: Paragraph highlighted for Winston-Salem review. Comment [c2]: highlighted for WS review. 5 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Alternative Daily Cover Procedures for Stormwater Separation Each lined landfill cell is divided by berms into hydraulically isolated subcells designed to allow the operator to limit the amount of stormwater entering the leachate collection system. Prior to placement of refuse in a subcell, the subcell must be isolated from the stormwater drainage system and connected to the leachate collection system. Isolation of the subcell from the stormwater system is accomplished by removing the stormwater pipe leading into the next subcell. The subcell is then connected to the leachate collection system by physically removing the geosynthetic rain cover (GRC) over the entire subcell. A GRC will be installed on top of either the operational cover located above the leachate collection layer or previously placed waste/soil cover to prevent stormwater from entering the leachate collection system. The GRC shall be installed according to manufacturer’s specifications. In general, the GRC can be ballasted by anchor trenches, tires, rope, or sandbags, or windscreen. Stormwater runoff is controlled by building up a berm underneath the GRC to act as a diversion ditch. Typically, the GRC is removed by rolling the material in a direction so as to roll it up the slope. Stormwater that has collected in isolated subcells that have not received waste is not considered leachate and may be pumped into sediment ponds as normal stormwater. Alternative Daily Cover At the end of each working day, either six inches of soil, or the following alternative daily cover an NCDEQ Aapproved Alternative Daily Cover (ADC) material, (ADC) will be used to encapsulate exposed refuse. The City’s sources approved options for ADC are listed below. NCDEQ approved material (ADC) is documented in the following: Approved Alternative Daily Cover Materials Forfor Use at Sanitary Landfills, as amended Date of Issue: January 7, 2014 Document number 20365 Examples of approved ADC are: • Construction and Demolition Debris (C&D) Fines • Combustion Residuals (CR) Ash • Spray-Applied Mortar Coating (PpPosi-sShell®) • Synthetic Tarps • Petroleum Contaminated Soils (PCS) • Water Treatment Sludge-Foam Coating • Foundry Sand • Auto fluffAutomotive Shredder Residuals (ASR) • Soil/Mulch mixture Comment [c3]: highlighted for WS review. 6 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Concrete, Asphalt, and Brick Operations The approved ADCs Posi-shell and tarps will be handled and applied by methods documented in the above mentioned document. approved by the manufacturer. PCS will be accepted at the landfill for use as ADC provided it meets the NCDEQ acceptance criteria. For PCS to be accepted on site, the material must have been tested for Total Petroleum Hydrocarbons (TPH). A contamination level of 3,000 parts per million (ppm) or less of TPH is required for acceptance. The material should be tested in accordance with the EPA guidance document SW-846 Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Soils originating from a cleanup or removal of an underground storage tank (UST) or deriving from a spill or other activity regulated under General Statute 143-215, 15 NCAC 2H and 15A NCAC 2C require a Certificate of Approval for Disposal of Soil Containing Petroleum Products (GW-71) issued by the Division of Water Quality or the UST Section of the Division of Waste Management. If the material is not used immediately as ADC the landfill will stockpile the PCS material within the lined landfill. The landfill may stockpile up to 33,000 cubic yards of PCS material based on an estimated average daily cover soil use over a 45-day period. The stockpiled soils shall be covered with a tarp or similar material for storage, or maintained at a moisture level sufficient to prevent blowing dust. Runoff from the PCS storage area shall be directed to the leachate collection system. The landfill shall maintain records in the facility operating record indicting how much PCS was received and utilized for ADC. Water treatment sludges will be utilized as a soil conditioner and incorporated into the daily/intermediate cover. Prior to using Auto fluff and water treatment sludge as daily cover, the landfill will apply for and complete a demonstration project for NCDEQ. As a contingency, the City will maintain a soil stockpile on-site for use as daily cover, should circumstances warrant it. Any area not receiving waste for a period of 12 months will have a minimum of 1 foot of intermediate soil cover. Concrete, Asphalt, and Brick Operations Concrete, asphalt, and brick (CAB) is received, inspected, unloaded and stockpiled at the landfill within the areas shown on Figure 1the Facility Plan-1. A trained inspector will visually inspect every load to assure that only loads of clean, uncontaminated CAB are unloaded and stored at the designated location. Any loads that are found to contain anything other than clean, uncontaminated CAB will not be allowed to unload and will be directed to unload at the working face of the MSW disposal area at the landfill and the hauler will pay the full tip fee for the load unless the hauler chooses to take the load to another landfill permitted to accept such waste. Incidental amounts of glass, sheetrock, plastic and other materials normally found at construction or demolition sites may be accepted during the test projectMaterials other than CAB discovered after unloading and will be properly and safely manageddisposed of at the landfill. Comment [c4]: highlighted for WS review. 7 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Explosive Gases Control Regardless of the amount of CAB received, the landfill will not accept and stockpile more than the capabilities of the storage areas identified. At approximately 50,000 tons of CAB, the landfill will immediately proceed to the final stage of the process, which includes turning the stockpiled CAB into stone for use in Winston-Salem landfillsat the facility. This will involve the retaining of a vendor to crush, chip or otherwise process the large pieces of CAB into useable aggregate. This processed material will then be stockpiled within the same area for periodic use in Winston- Salem landfillsonsite. Explosive Gases Control A gas monitoring system has been constructed around the perimeter of the Existing landfill by a third party. The existing system will be expanded to cover the proposed landfill expansion. This system will monitor for gas migration along the perimeter of the landfill expansion. All buildings and enclosed structures at the landfill will be monitored as part of a routine methane monitoring program. Methane Monitoring Well Placement In accordance with Rule 1626 (4)(b)(I), the following factors were used to determine gas monitoring well placement: soil conditions, hydrologic conditions, hydraulic conditions, and location of facility structures. Monitoring well locations are shown on the Landfill Gas Monitoring Plan provided in the appendicesLandfill Gas Monitoring Plan. Methane Monitoring Program Routine monitoring for gas migration will be performed in accordance with Rule .1626 Part (4)(ba) on a quarterly basis to ensure that the following compliance levels for methane concentration are not exceeded: 1) the concentration of methane gas generated by the facility does not exceed 25 percent of the lower explosive limit (LEL) for methane in facility structures (1.25 percent methane); and 2) the concentration of methane gas migrating from the landfill expansion does not exceed the LEL for methane at the facility property boundary (5 percent methane). The monitoring device that will be used will be a combustible gas indicator (CGI). If concentrations are measured at greater than 25 percent of the LEL for methane in facility structures, then the landfill must immediately take all necessary steps to ensure protection of human health and shall notify the Division of Solid Waste Management. Within seven days of detection, the methane gas levels detected and a description of the steps taken to protect human health shall be placed in the operating record. Within 60 days of detection, a remediation plan describing the nature and extent of the problem and the proposed remedy for methane gas releases shall be placed in the operating record, the remediation plan shall be implemented, and the Division of Solid Waste Management shall be notified. Sampling and Analysis Procedures The City may have an independent contractor perform methane sampling and analysis in accordance with the Landfill Gas Monitoring Plan. 8 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Sedimentation and Erosion Control Emergency Response Plan In the event methane gas levels exceed allowable limits within structures, the emergency response plan will be as follows. • For structures with greater than 25 percent LEL: o evacuate immediately, leaving doors open, o notify Winston-Salem Fire Department Hazardous Material Team, o notify NCDEQ, o notify consulting engineer, and o follow emergency procedure outlines in 15A NCAC 13B.1626(4)(c). • For structures with 0-25 percent LEL: o conduct follow-up monitoring, and o discuss with consulting engineer. Sedimentation and Erosion Control The landfill expansion area will be constructed with maximum waste sideslopes of 3H:1V and minimum 8% top slopes to promote runoff and prevent ponding over or in the waste. Side slope terraces and perimeter drainage channels at the toe of the slope will provide runoff, erosion, and sediment control. The drainage channel allows for the movement of surface water from landfilling activities and provides a settling zone for sediments carried from the site. The channel is constructed to allow drainage via sediment basins through natural outfalls and tributaries to Grassy Creek. Measures to control sedimentation and erosion will include the drainage channel, sediment basins, silt fences, slope drains, sediment traps, temporary and permanent seeding. Within 30 working days or 120 calendar days of completion of any phase of landfill development a vegetative ground cover sufficient to restrain erosion will be accomplished. All measures will be constructed or installed in accordance with standards specified in the North Carolina Erosion and Sediment Control Planning and Design Manual. Sediment basins will also prevent the discharge of pollutants that violate requirements of the Clean Water Act, including, but not limited to, NPDES requirements, into the waters and wetlands of the United States. The landfill expansion area will have a comprehensive surface and groundwater monitoring program to provide early detection of any leachate migration problems. In the event any constituents are detected above allowable limits, measures will be taken to begin assessing the extent of contamination and, if necessary, corrective actions will be taken to prevent the pollution of waters and wetlands of the United States, that violate any requirements of an area- wide or state-wide water quality management plan that has been approved under Section 208 or 319 of the Clean Water Act, as amended. 9 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management Leachate Management General Collection and removal of leachate generated from waste within expansion landfill will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, they will be cleared of debris using the cleanout riser pipes for access. The maintenance and cleaning will be performed on an annual basis or as necessary basis to maintain the free flow of leachate in accordance with NC General Statutes 130A-295.6(h)(3). The facility reserves the right to request that the Department allow the leachate lines to be cleared every two years, also in accordance with NC General Statutes 130A-295.6(h)(3). The pipes will be cleaned with jetted water and all cleanings will be recorded on the Leachate Pipe Cleaning Form. If pipes are damaged, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Remote camera inspections of the leachate lines will occur upon completion of construction, at least once every five years, and following the clearing of all blockages in accordance with NC General Statutes 130A-295.6(h)(3). Records of the inspections will be recorded on the Remote Camera Video Inspection Form. The Phase 2 collection system includes collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C, respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the existing landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. 10 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Cleaning Report in the file. Leachate Pipe Cleaning Form* Pipe ID Date Cleaning Company Persons Operating the Equipment Comments about Cleaning Comment [c5]: WS to confirm the use of this form 11 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Inspection Report in the file. Remote Camera Video Inspection Form* Pipe ID Date Inspection Company Persons Operating the Equipment Comments about Inspection 12 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management According to the letter dated September 13, 2005 from the City/County Utilities Department, the landfill is not required to have a permit to discharge leachate at the wastewater treatment plant. Leachate Pretreatment and Discharge At this time, leachate pretreatment is anticipated to consist of only equalization in the storage tanks. Existing on-site leachate quality tests do not indicate a need for pretreatment at this time. Testing of leachate quality will continue during the life of the Hanes Landfill facility. Dependent on the outcome of future tests, an appropriate system, if required, will be designed. Separation of Stormwater Storm water control measures will be employed within lined subcells which have not received waste. These measures include “sectioning off” unused subcells or portions of subcells by employing GRC and temporary subcell divider berms. In addition, a sump will be created at the low end of the subcell to facilitate stormwater removal. In general, temporary sumps are formed where the subcell divider berms intersect the perimeter berm. Stormwater drains toward the temporary sumps on top of the GRC. The formation of temporary sumps permits stormwater to be pumped as required. In this way, the landfill expansion operator retains a degree of flexibility throughout the life of the landfill expansion. As filling operations are initially proceeding, stormwater from unfilled subcells is kept out of the leachate collection system. The temporary sumps also enable the operator the potential to monitor both the quantity and quality of leachate and enable separation or isolation of specific areas in the event of a problem. Prior to the commencement of filling activities in the subcells, the temporary discharge pipes will be removed to prevent discharge of leachate into an inactive subcell. Leachate Quality Sampling Semi-annual sampling will be performed in accordance with .1626(12)(c). Samples will be recovered as grab samples from the leachate storage tank. The parameters to be analyzed will include BOD, COD, temperature, conductivity, phosphate, pH, ammonia, suspended solids, sulfates, nitrates, and metals analysis. Analyses will also include a volatiles scan. Please refer to Section 6.0the, Water Quality Monitoring Plan, of the Design Hydrogeological Report for more detail. CFR 258 Appendix I outlines the list of metals and volatiles to be tested. Leachate Contingency Plan In the event that leachate levels within the first tank reach the freeboard capacity, a high crossover pipe will allow flow into the second tank. In the event that both tanks reach the freeboard capacity due to unforeseen events, the excess leachate will either be piped directly to the sewer and then to the POTW or stored temporarily in the landfill expansion. Engineering structures (secondary containment) have been constructed to prevent leachate from entering local waterways. If operational conditions allow, leachate recirculation may be performed with prior NCDEQ approval. 13 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Air Quality Control Air Quality Control Mandates of the US Environmental Protection Agency (EPA) Clean Air Act and corresponding Forsyth County regulations will be met as they become effective. The primary control mechanism will be the proposed active gas extraction system. All equipment at the facility will have fire extinguishers on board. The extinguishers will be properly classified and inspected. All operators will be trained for proper use of extinguishers. Open burning of solid waste is prohibited at the site. The fire department will be notified in cases of emergency, such as a landfill fire. NCDEQ will be notified by a phone call within 24 hours of a landfill fire. A follow-up report detailing the nature of the fire and any respective action taken will be mailed to NCDEQ within 15 days of the landfill fire. Access and Safety Requirements The facility is almost totally enclosed by a 6-foot chain link fence with triple strands of barbed wire to prevent unauthorized entry into the site. Areas currently not protected by fencing are inaccessible by motor vehicle due to steep water barriers, railroads etc. The access road to the working face will be of all-weather construction and kept in good condition. Dust control and tracked mud will be controlled on the access roads as needed. Proper signage directing and informing facility users will be placed in high visibility areas, including signs stating that no hazardous or liquid wastes can be received. Removal of MSW from the facility will not be allowed without the approval of the facility supervisor. Under no conditions will the removal of MSW from the working face be allowed. No barrels or drums will be disposed of at the facility without sufficient perforations to ensure that no liquid or hazardous wastes are contained in them. The facility will be staffed during all operating hours to ensure operational compliance. Spreading and Compacting Program Incoming waste at the facility will be confined to the smallest most efficient working face feasible. Solid waste will be compacted as densely as practical into cells. Appropriate control devices such as berms, fences, and cover material will be used as needed to prevent windblown debris. Any windblown debris will be collected by on-site staff or temporary laborers.. The landfill also has a litter control program. For example, the landfill has installed litter control fences that help capture blowing litter. In addition to these fences, labor is also used to manually remove the blown litter that lies outside the environs of the working face. In the event of extremely windy days, temporary labor and/or prison/community service labor will be used to remove the blown litter. This windblown litter will be bagged and returned to the working face. 14 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Record Keeping Program Record Keeping Program Records for tonnage and waste generators will be kept at the office of the City’s Solid Waste Administrator and made available to NCDEQ upon request within a reasonable period of time. Records for facility inspections, gas/groundwater monitoring results and corresponding analytical data, closure/post-closure cost estimates, financial assurance documentation and employee training will be kept at the facility. The information will be made available to NCDEQ upon request within a reasonable period of time. Copies of the operation plan will be kept at the facility. 15 Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents Contents Cap System Background ........................................................................................................... 1 Cap System Design ................................................................................................................... 1 Final Contour Requirements ...................................................................................................... 2 Cap System Material Requirements ........................................................................................... 2 Surface Water Control Measures ............................................................................................... 2 Permanent Erosion Control Measures ....................................................................................... 3 Settlement Subsidence and Displacement ................................................................................. 3 Leachate Control ........................................................................................................................ 3 Gas Collection/Venting System .................................................................................................. 3 Schedule for Closure.................................................................................................................. 3 Notice of Closure and Date of Final Waste Acceptance ............................................................. 4 Implementation of Closure Plan ................................................................................................. 4 Closure Verification .................................................................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Cap System Background Cap System Background In compliance with the NCDEQ Solid Waste Management Rules, the landfill expansion will place a final cap system over all waste placed in the proposed expansion. The layers of the cap system will be designed and constructed in accordance with Rule .16247 (bc) (83), (9), and (15), to minimize infiltration and erosion. It is estimated that the total landfill volume at completion will be 12,200,000 cubic yards for the 90+/- acres foot print. The maximum area requiring a cap at any one time shall be 65 acres. Cap System Design The desired cap system design may change as new technologies develop. The cap system designed will be checked prior to closure, revised and updated permitted as appropriate. Compacted soil liners will be incorporated in the cap system design to provide protection throughout the 30-year post-closure period and beyond. The regulatory prescriptive system will consists of four layers (bottom up); the compacted soil liner; a geomembrane; a drainage layer (possibly a geonet layer or more appropriate layer); and the erosion layer. The geomembrane and compacted soil liner form a composite barrier designed to reduce infiltration into the landfill expansion, thus minimizing leachate and the potential for groundwater contamination. The erosion layer is designed to protect the composite barrier. The expansion landfill may use on-site or off-site borrow material for the compacted soil layer. The compacted soil layer will consist of no less than 18 inches of soil having permeability equal to or less than 1 x 10-5 cm/sec. In order to assure that the material meets the permeability criteria, the soil will be tested prior to use and after placement. Testing requirements will be outlined in the final closure plan. It is anticipated that the upper 6 inches of the intermediate cover will be suitable for compaction and incorporation into the compacted soil layer. Construction methods for the compacted soil liner shall be based upon the type and quality of the borrow source and shall be verified in the field by constructing test pad(s). A professional engineer shall certify that the compacted soil liner installation conforms with the plans approved by the NCDEQ Division of Solid Waste Management. While NCDEQ rules require that the erosion layer shall consist of no less than 6 inches of earthen material capable of sustaining native plant growth, it is anticipated that the erosion layer for closure of the expansion landfill will consist of 12 inches of suitable on-site borrow material. That 12-inch layer will then be covered with a 6-inch topsoil layer. The materials of the erosion layer will be selected considering: soil type, nutrient levels, pH, erodibility, sideslope drainage, and other factors. The vegetation (typically Kentucky Fescue) should be selected based on the following criteria. • Species of grasses which are locally adapted and resistant to drought or temperature extremes. • Having roots which will not disrupt the low permeability layer. • Ability to thrive in low nutrient soil and develop a good stand to resist erosion. Formatted: Superscript 1 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Final Contour Requirements • Able to survive and function with little or no maintenance. All cover material will be free of putresibleputrescible material, solid waste, vegetation, rocks, construction debris, frozen soil, and other deleterious materials. Seismic and general slope stability analyses have been performed and can be found in the Appendix Phase 2 Application to Construct. Final Contour Requirements The final contour requirements for closure are shown on the drawings included with theis Phase 2 permit Application to Constructamendment. These contours have been established to reflect all municipal solid waste expected to be received, intermediate cover material (representing an initial total of 12 inches and a final total of 6 inches), and the final cover system (representing a total of 3 feet). Cap System Material Requirements Based on the cap design submitted in this amendment, 18 inches of compacted soil placed over the Phase 1 and 2 areas at final closure, 157,000 cubic yards of compacted soil will be required for the first layer of the cap system. A minimum of 105,000 cubic yards will be required for the erosion layer soil. An estimated 52,500 cubic yards of earthen material will be required for the 6 inches of top soil layer. An estimated 2,831,400 square feet of geomembrane will be used in drainage ways and on the top slopes of the completed landfill. The following table summarizes the cap system requirements for Phases 1 and 2 of the landfill expansion area. Table 5-1 Cap System Requirements - Phases 1 & 2 Material Quantity 18-inch Compacted soil liner 157,000 CY 12-inch Erosion layer soil 105,000 CY 6-inch Top soil layer 52,500 CY Geomembrane 2,831,400 SF Surface Water Control Measures The landfill expansion area is designed to have top slopes of 8 percent and side slopes of 3H:1V. Final contours have been established to allow the landfill expansion surface water to drain off the final cover while limiting erosion potential and maintaining post settlement slopes greater than 5 percent. Surface water runoff from the top slopes is intercepted by a diversion berm that separates the top slopes from the side slopes and carried off of the cover via down pipes. The side slopes incorporate a system of drainage terraces to limit surface water flow length. The vertical spacing of the side slope terraces is approximately 40 feet. The side slope terraces will drain into the down pipes which, in turn, drain to the perimeter drainage channel. The surface waters will be conveyed by the perimeter drainage channel to one of four sedimentation basins located adjacent to the landfill expansion. The maximum length of sheet 2 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Permanent Erosion Control Measures flow (~300 ft) will occur on the 8 percent slopes. Drainage terraces will direct flow across the 3H:1V percent slopes into the down pipes and into the sediment basins. Permanent Erosion Control Measures The expansion landfill is situated near an intermittent stream at the southern end of the site and adjacent to Grassy Creek. A system of drainage channels and sedimentation basins will be used to protect the intermittent stream and Grassy Creek from sediment laden runoff. The sedimentation basins were designed to control the 25-year storm event and achieve a minimum of 70 percent efficiency in settling a sediment particle with a diameter of 40 microns. The sedimentation basin design calculations may be found in the Application to Construct calculations section. Settlement Subsidence and Displacement Landfill compaction methods which include the use of steel-wheeled compaction equipment to spread and compact in layers not to exceed 2 feet in thickness, combined with an adequate number of passes over each layer of waste, will be utilized to reduce voids and minimize differential settlement. Proper placement of daily, intermediate, and final cover will reduce the moisture content of the waste prior to site closure and further reduce settlement. Final slopes of the landfill expansion have been developed to allow for this anticipated subsidence so that long- term positive drainage of the fill will not be hindered. Leachate Control The installation of the final cap system over the fill area will greatly reduce infiltration of surface water and lessen the potential for leachate generation. The landfill expansion area has a comprehensive surface and groundwater monitoring program to detect any potential leachate migration problems. This program, which is discussed in Section 8.0 of this documentWater Quality Monitoring Plan, will be continued throughout the post-closure care period. Gas Collection/Venting System It is anticipated that aAn active gas venting system will be installed under the cap to allow movement of gas generated from the completed fill area to the existing gas collection system. The gas collection system will be an extension of the one used at the existing landfill. The collection system is presently maintainedcontrolled by an independent contractor. Schedule for Closure The closure will begin after completion of a portion of the final grades as soon as possible. The design of the landfill expansion in combination with the maintenance plan should assure a fairly uncomplicated closure period. The closure of the entire unit, or portions thereof, will be completed within 180 days unless an extension has been requested and received due to changes in the anticipated schedule. Comment [c1]: Highlighted for WS review 3 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Notice of Closure and Date of Final Waste Acceptance Notice of Closure and Date of Final Waste Acceptance A sign indicating the anticipated date of closure and the date of final waste acceptance will be conspicuously posted at the facility at least 30 days in advance. The landfill may take other steps to notify the public of the planned closure. Prior to beginning closure of the unit or portions thereof, the NCDEQ Department of Solid Waste Management will be notified that a notice of intent to close has been placed in the operating record. Implementation of Closure Plan The closure plan will be implemented as soon as possible from the date of final waste acceptance and completed in accordance with state regulations. Closure Verification The following procedures will be implemented following closure. • A Construction Quality Assurance (CQA) report shall be submitted to the NCDEQ Division of Solid Waste Management. This report shall describe the observations and tests used before, during, and upon completion of construction to ensure that the construction materials meet the cap design specifications and the construction and certification requirements. The CQA report shall contain as-built drawings. • A signed certification from an independent registered professional engineer verifying that closure has been completed in accordance with the closure plan will be submitted to the NCDEQ Division of Solid Waste Management. • At least one sign notifying all persons of the closing of the phase and that wastes are no longer accepted will be posted. Suitable barriers will be installed as necessary at former accesses to prevent new waste from being deposited. • Within 90 days, a survey plat, prepared by a professional land surveyor registered by the State, indicating the location and dimensions of landfill disposal areas, will be submitted to the Forsyth County Register of Deeds circuit court clerk of the City.. • A notation shall be recorded on the deed notifying any potential purchaser of the property that the land has been used as a solid waste management unit and that future use is restricted under Paragraph (8) of Rule .1627. A copy of the deed notation as recorded shall be filed with the operating record. 4 Post Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents Contents Introduction ................................................................................................................................ 1 Post-Closure Contact ................................................................................................................. 1 Description of Use ...................................................................................................................... 1 Maintenance .............................................................................................................................. 1 Repair of Security Control Devices ......................................................................................... 1 Erosion Damage Repair ......................................................................................................... 2 Correction of Settlement, Subsidence and Displacement ....................................................... 2 Leachate Collection System ................................................................................................... 2 Closure of Storage Tanks ....................................................................................................... 3 Repair of Run-On/Run-Off Control Structures ......................................................................... 3 Gas Collection/Venting System .............................................................................................. 3 Groundwater Monitoring System ............................................................................................ 3 Monitoring Plan .......................................................................................................................... 4 Inspection Frequencies .......................................................................................................... 4 Quarterly Inspections .............................................................................................................. 4 Semi-Annual Inspections ........................................................................................................ 5 Engineering Certification ............................................................................................................ 5 Tables Table 1 Post-Closure Inspection Frequencies ........................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Introduction Introduction This Post-Closure Plan has been developed to outline steps to be taken to ensure the environmental soundness of the landfill expansion during its post-closure care period. The post- closure period begins when the Closure Verification Report is submitted to NCDEQ. The post- closure care period will be in accordance with the latest NC regulations, 15A NCAC 13B .1627 (d).last at least 30 years after closure completion and at a minimum and will consist of the following. • Maintaining integrity and effectiveness of final cover system. • Performing groundwater and surface water monitoring. • Maintaining and operating a gas monitoring system. • Maintaining run-on/run-off controls. No wastes will remain exposed after closure of the unit. Access to the closed site by the public or domestic livestock will not pose a health hazard. Post-Closure Contact All correspondence and questions concerning the post-closure care of the unit should be directed to: Solid Waste Administrator City of Winston-Salem Hanes Mill Road Landfill 325 West Hanes Mill Road Winston-Salem, NC 27105 336-747-7310 Description of Use After filling operations cease at the landfill expansion area and the unit is officially closed in accordance with the Closure Plan, the area will be allowed to return to a natural vegetative state. The City will maintain control of the property. The City may develop the land for recreational uses such as greenways, parks, etc. There will be an access road on the cap to allow proper maintenance during post-closure. Final location of the access will be determined as a part of operations. Maintenance Repair of Security Control Devices All security control devices will be inspected and maintained as necessary to ensure access to the site is controlled. Locks, vehicular gates, and fencing will be replaced if functioning improperly. Warning signs will be kept legible at all times and will be replaced if damaged by inclement weather or vandalism. 1 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance Erosion Damage Repair If erosion of the final cover occurs during post-closure, the affected area will be repaired and re- seeded as necessary. Excessive slopes will be flattened if possible by adding clean fill material. If necessary, erosion control fabrics will be used to expedite rapid re-vegetation of slopes and to secure topsoil in place. Rough surfaces which cause isolated erosion areas will be smooth and re-seeded as necessary. Correction of Settlement, Subsidence and Displacement Slopes will be maintained in order to prevent ponding and allow for proper drainage without infiltration. If vertical or horizontal displacement occurs due to differential settlement, cracks will be filled with appropriate material and final cover will be reestablished. Excessive vertical displacement is not anticipated. Leachate Collection System Collection and removal of leachate generated from waste will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, the pipes will be cleared of debris using the cleanout riser pipes for access. All leachate collection lines shall be designed and constructed to permanently allow cleaning and remote camera inspection. All leachate collection lines shall be cleaned as found necessary for proper function and to address buildup of leachate over the liner. at least once per year, except that NCDEQ may allow leachate collection lines to be cleaned once every two years, if the facility has continuous flow monitoring and the permit holder demonstrates to the NCDEQ that the leachate collection lines are clear and functional based on at least three consecutive annual cleanings. Remote camera inspections of the leachate collection lines shall occur at least once every 5 years during the post closure period and following the clearing of blockages. If leachate pipes fracture, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Although total failure of the leachate collection system is unlikely, it may be possible to remove leachate from sumps constructed at the natural drainage points inside the lined area. The Phase 2 system includes leachate collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the closed landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. The sideriser pumps will be maintained in good working order throughout post-closure. Since leachate volume will be decreased during post-closure, the maintenance schedule will be adjusted in accordance with manufacturer’s recommendations. As during landfill operations, a 2 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance high-level alarm system will be in place to warn of pump failure or other system breakdowns. Further, due to the design of the system, the high-level alarm will serve as a monitoring system for prevention of greater than 1 foot of leachate head on the liner system. Closure of Storage Tanks After closure of the landfill expansion area has been achieved, the generation of leachate will eventually curtail. The flow rate immediately after closure should decrease to less than 100 gallons/acre/day (gpapd). Toward the end of the 30-year post-closure period, the flow should approach zero, at which time the storage tanks will not be required. The following procedures will be followed to properly close the storage tanks. • Completely drain and remove all liquids, sludges, sediments, etc. from the storage tanks. • Disassemble the tank, piping, and appurtenances and dispose of the contents in a manner approved by NCDEQ. • Sample and analyze the soil for appropriate constituents inherent to leachate. Assess the results for evidence of contaminant migration. • If contamination of underlying soils is exhibited, perform an assessment as to the degree of contamination and develop remedial actions. • Obtain approval of NCDEQ for the assessment and associated remedial measures. • Perform the remedial actions as necessary to limit any threats to public health and the environment. • Install permanent vegetation in the vicinity of the containment area. Activities may include filling, grading, topsoiling, and seeding. Repair of Run-On/Run-Off Control Structures All side slope terraces, ditches, and perimeter channels will be repaired, cleaned, or realigned in order to maintain original condition. Any culverts that are damaged will be replaced. Gas Collection/Venting System The landfill gas collection and venting system will be maintained. Currently, a third party manages and operates the existing gas system. Proper operation of the systems is verified through testing at the landfill gas monitoring wells and probes. If methane gas recovery wells do not function as a result of irregular settlement, accumulation of liquids (condensate, leachate, and water), binding or corrosion, replacement wells can be installed if necessary. Non-functioning vents will be reset if necessary. Groundwater Monitoring System A Water Quality Monitoring Plan (WQMP) is included as Section 6 this amendment. Procedures outlined in the WQMP, or subsequent revision, will take precedence over the brief description provided here. All groundwater monitoring wells have been installed with concrete pads and protective casings to prevent accidental damage by vehicles and equipment. The wells are also equipped with a locking cap to discourage vandalism. Groundwater wells will be inspected regularly (at the time of sampling) to ensure integrity. Persons inspecting a well should look for 3 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Monitoring Plan signs of well tampering, cracking or degradation, and determine whether the well needs to be replaced. If the decision is made to replace and abandon a well, the replacement well should be installed 5 to 10 feet from the abandoned well in accordance with previous well specifications. Well abandonment should be accomplished by pulling the casing out and grouting the hole. Refer to the approved Water Quality Monitoring Plan for detailed information on the groundwater monitoring system Monitoring Plan The closed unit shall be monitored in accordance with 15A NCAC 13B .1627 (d)for 30 years. A series of inspections shall be scheduled to ensure the integrity and effectiveness of the cap system, storm water control system, groundwater monitoring system, gas collection system, and to protect human health and the environment. Inspection Frequencies Inspections to be conducted during the post-closure care period will occur regularly as shown in Table 7-1 below. A copy of the Post-Closure Inspection Checklist is included at the end of this sectiondocument. Table 1 Post-Closure Inspection Frequencies Inspection Activity Years 1-3 Years 4-30 Security Control Devices Quarterly Quarterly Cover Drainage System Functioning Quarterly* Semi-annually Leachate Collection System Quarterly Semi-annually Gas Collection/Venting System Quarterly Semi-annually Groundwater Monitoring System Semi-annually Semi-annually Erosion Damage Quarterly* Quarterly Cover Settlement, Subsidence, and Displacement Quarterly* Semi-annually Vegetative Cover Condition Quarterly* Quarterly Stormwater Control System Quarterly* Quarterly Benchmark Integrity Annually Annually Leachate Collection Pipe Flushing Annually Annually * These items will also be inspected in accordance with the current NPDES Permit. within 5 days of each major storm event (i.e., 1 inch or greater in any 24-hour period.) Quarterly Inspections Quarterly inspections of the closed site will include examination of the security control devices for signs of deterioration or vandalism to ensure access to the site is limited to authorized persons. The previous disposal area will be checked to ensure the integrity of the final cover system is maintained, erosion damage is repaired, vegetative cover persists, and that cover settlement, subsidence and displacement are minimal. Drainage ditches will be cleared of litter and debris and benchmark integrity will be noted and maintained. 4 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification Semi-Annual Inspections Semi-annual inspections of the site during the post-closure period will be conducted by the City’s engineer with attention paid to integrity and drainage of the final cover system and proper functioning of the groundwater and gas monitoring systems. Groundwater monitoring will continue on a regular basis throughout the post-closure care period. The parameters chosen for analysis will be no less than the requirements of regulatory agencies. Groundwater monitoring wells will be inspected in accordance with the post-closure inspection protocol. A report of findings will be made to the responsible party via the Post- Closure Inspection Checklist, including any recommendations for actions necessary to ensure the site continues to meet the closure performance standard. The engineer will also receive copies of the quarterly inspections reports and respond to any comments that demand immediate attention. Engineering Certification Based on the City’s monitoring reports and an engineer’s semi-annual site visits, annual certifications by the engineer will be placed in the operating record. They will certify that the closure plan has been followed, noting discrepancies along with the corrective actions undertaken. At the end of the post closure period, the individuala certifications will be compiled into a final document and forwarded to NCDEQ Division of Solid Waste Management. 5 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification Post-Closure Inspection Checklist Location: Date: Time: Weather: Completed By: Yes No I. Security Control Devices: Are security control devices in place and functioning?   Are all warning signs prominent and legible?   Are there any signs of unauthorized entry on the site?   Are there signs of illegal dumping on site?   II. Final Cover System: Is the final cover free of erosion and depressions?   Is there leachate seeping from the final cover? (If yes, make note of location on comment section below.)   Is the vegetative cover continuous and in good condition, free of bare spots?   Does the site require mowing? (If yes, mow grass and note in comment section below.)   Is there ponding of water on final cover system?   III. Groundwater Monitoring Wells: Is the casing upright and unobstructed?   Is the outer casing secure and locked?   Is the ID tag present and legible?   IV. Miscellaneous: Are all benchmarks visible and intact?   Are all ditches free of debris and litter?   Are any odors present which may indicate landfill gas migration?   6 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification COMMENTS Please use the section below to comment on any area not covered above and also to note any areas of concern or needing immediate attention. 7 Water Quality Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents Contents Purpose and Intent ..................................................................................................................... 1 Background ................................................................................................................................ 1 Hydrogeologic Setting ............................................................................................................ 2 Water Quality Monitoring Program for Unit 1 .......................................................................... 5 Proposed Water Quality Monitoring Plan.................................................................................... 5 Sampling Locations ................................................................................................................ 6 Data Collection ....................................................................................................................... 7 Well Construction ..................................................................................................................11 Analytical Procedures ............................................................................................................11 Tables Table 1 Summary of Monitoring Sample Locations and Functions ...........................................10 Table 2 Monitoring Network Well Construction Details .............................................................11 Table 3 Updated MNA Monitoring Parameters and Methods ....................................................12 i City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Purpose and Intent Purpose and Intent The purpose of this Revised Water Quality Monitoring Plan (Plan) is to provide a program for the collection and evaluation of groundwater, surface water and leachate samples at Unit 1 of the Hanes Mill Road Municipal Solid Waste Landfill (Landfill). The Plan describes the monitoring program for both the Subtitle D area and the unlined landfill area of Unit 1. This program evaluates samples from groundwater wells installed in the uppermost aquifer, as well as surface water, and leachate from the leachate collection system. Implementation of this plan will provide efficient and effective early detection of any release of hazardous constituents to the uppermost aquifer, so as to be protective of public health and the environment as well as evaluate the efficacy of ongoing corrective actions. As the waste mass continues to stabilize and remediation progresses, it is anticipated that the monitoring program will need to be periodically adjusted. As the groundwater remediation model continues to be validated over time, fewer confirmatory groundwater samples will be required. This Plan was prepared in accordance with North Carolina Solid Waste Management Rules 15A NCAC 13B, Sections .1630 through .1637 under the guidance of a North Carolina licensed geologist. Background The Landfill is located at the intersection of US Highway 52, Hanes Mill Road, and Ziglar Road and is owned and operated by the Winston-Salem/Forsyth County Utility Commission (Commission) under North Carolina Permit No. 34-02. Unit 1 of the Landfill is composed of an unlined portion (now closed) and a Subtitle D lined portion (aka the “piggyback”). Unit 1 ceased receiving waste in August 2005 and the Commission is now disposing of waste in the Expansion Landfill. The Expansion Landfill is not addressed in this section. The Commission conducted routine detection groundwater monitoring (Appendix I constituent list, per Rule 15A NCAC 13B .1633) for the unlined landfill until 1995. In 1995 and 1996, an assessment groundwater monitoring program (Rule 15A NCAC 13B.1634) was initiated due to exceedances of the North Carolina Groundwater Quality Standards (15A NCAC 2L, .0202). This assessment demonstrated that all impacts were limited in extent and confined to the facility’s property. The exceedances occurred in two monitoring wells located approximately 50 feet from the edge of the waste and resulted mainly from two sources of Volatile Organic Compounds (VOCs): primarily chlorinated solvents and their breakdown products and secondarily, benzene, toluene, and ethylbenzene – constituents found in petroleum products. An Assessment of Corrective Measures (ACM) was conducted and, based on the results, monitored natural attenuation (MNA) was selected as the most appropriate and cost-effective of the remedial options for the cleanup of the dissolved VOCs at the Landfill. This ACM was approved by the North Carolina Department of Environment and Natural Resources (NCDENR) in a letter dated March 24, 2005 (Gamble to McHargue). MNA involves collecting and evaluating data to document that the processes of natural attenuation are continuing to occur and are effective in meeting the remedial objectives. The Corrective Action Plan (CAP) to conduct MNA 1 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background at the Landfill was prepared and approved by NCDENR. Baseline MNA monitoring was completed and an assessment was detailed in the Springspring 2008 Semiannual Report. In response, NCDENR approved the request to remove four OW wells from the MNA monitoring on September 22, 2008 (including OW-6, OW-7DA, OW-11, and OW-13D). In accordance with the request from NCDENR, the addendum to the CAP was submitted to include additional corrective action measures and to revise the MNA monitoring plan. In the addendum, one background well (MW-1RR) and six down gradient wells (OW-3, OW-4, OW-10D, OW-12, OW- 14, and OW-17D) are included in the continuing MNA monitoring program which includes testing of Appendix II parameters. In a letter dated March 4, 2010 (Drummond to McHargue), NCDENR approved a request for a modification to reduce Appendix II groundwater monitoring to every other spring monitoring event at the closed unlined landfill beginning in 2011. As requested by NCDENR four independent samples were collected at the wells monitoring the closed unlined landfill (including the subtitle D cell) for detected Appendix II parameters to establish background groundwater concentration. Hydrogeologic Setting The Landfill is located in the southern Piedmont physiographic province of North Carolina. The physiography of the Piedmont is characterized by gentle to rough sloping terrain that becomes increasingly sloped closer to the mountains and is dissected by a well-developed drainage system. The topography is developed on deeply weathered, belted metamorphic and igneous rocks that generally date from late Precambrian to Paleozoic Era. According to the soil survey of Forsyth County, North Carolina, prepared by the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) (1976), the surficial soils at the Landfill belong to the Pacolet-Cecil association. These soils are characteristic of Piedmont uplands where well-drained soils with a loamy surface layer and a clayey subsoil layer are found predominantly on gently sloping to sloping land. The Landfill is dominated by three main soil series as shown on Sheets 9, 10, 15, and 16 of the survey. These include the Hiwassee series, the Pacolet series, and the Madison series. A fourth series (Chewacla series), found outside of the footprint of the proposed landfill unit(s), is present along the floodplain of Grassy Creek. According to the geologic map of the east half of the Winston-Salem Quadrangle, North Carolina-Virginia, compiled by Espenshade and others, 1975; the geologic units identified at or adjacent to the Landfill include the following: pCag-Ashe Formation, pCaa-Ashe Formation, bc- Charlotte Belt rocks, and qgc-Charlotte Belt rocks. Nearly all of the Landfill property is underlain by typical Ashe Formation lithologies. Field checks of the local geology confirm this conclusion. The lithologic protoliths include turbidite facies (the bulk of the formation) and basalt flows (the amphibolite facies). The Ashe Formation is estimated to be 12 to 15 kilometers in thickness (Rankin, D.W., 1970). The main surface water drainage features of the Landfill are the two tributaries of Grassy Creek to the north and south of the property, and Grassy Creek itself to the west. Surface water drainage from the area of the existing Landfill is controlled through a series of catch basins and sediment ponds. Some surface water drains from the Landfill area into both the north and south 2 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background streams, which then carry it to Grassy Creek via culverts beneath the Norfolk Southern railway at the west edge of the Landfill. Other surface water flows directly from the Landfill area to Grassy Creek via two culverts located between the north and south streams. The 100-year floodplain of Grassy Creek is located between 150 and 300 feet west of the Landfill at a topographic elevation between 800 and 805 feet msl. Since both of the bounding streams are perennial, they are also areas of groundwater discharge at the Landfill. Groundwater flow for this portion of the Landfill property is primarily west towards Grassy Creek, with minor components of groundwater flow towards two bounding streams named North Branch Creek (NBC) and South Branch Creek (SBC). Groundwater in the Piedmont occurs both intergranularly in the weathered saprolite and within fractures in the bedrock. Typically, the water table is within the saprolite, and water supply wells are completed in bedrock. Total porosity in saprolite is generally relatively high with measured values as high as 40 to 50 percent. In bedrock, porosity is normally only 3 to 5 percent, but fractures are often well connected and hydraulic conductivity is comparable to or higher than that found in the saprolite. As the saprolite and bedrock are hydraulically connected, the contrast between porosities allows the saprolite to act as a groundwater reservoir for wells that pump from the bedrock. Sustained well yields for well-constructed bedrock wells in the Piedmont average from approximately 15 to 30 gallons per minute (Charles C. Daniel, III and R.A. Payne, 1990). The water table in the Piedmont, under natural conditions, is a subdued image of the surface topography. Recharge takes place on interfluvial areas, then travels downward and laterally to discharge along creeks and rivers. Thus, the vertical component of groundwater flow is directed downward in interfluvial recharge areas, comprising approximately 80 to 90 percent of land surface, and then has an upward component of flow as groundwater moves to discharge areas at streams. The groundwater at the Landfill flows from the highland recharge area northeast of the Landfill toward Grassy Creek located west of the Landfill. Minor components of groundwater flow may also occur radially from the crest of the Landfill toward the drainage features to the north and south. Based upon several slug tests performed on selected wells and piezometers in the study area, the hydraulic conductivity of the uppermost limits of the saprolite aquifer is 1.61 feet per day (ft/day), while the hydraulic conductivity of the partially weathered rock (PWR) unit of the aquifer ranges from 0.78 to 5.77 ft/day. The upper limits of the fractured bedrock range in hydraulic conductivity from 1.40 to 3.77 ft/day. A groundwater flow velocity was calculated for each well location using a variation of Darcy’s Law. Employing the average hydraulic conductivity values for the saprolite/PWR and bedrock units, an estimated groundwater flow velocity was calculated for the well locations along the eastern side of Grassy Creek and the southern side of SBC. Assuming an effective porosity of 20 percent (0.20) for saprolite and PWR wells and 5 percent (0.05) for rock wells, with calculated hydraulic gradients associated with the vicinity of each of these monitoring wells, a groundwater flow (pore water seepage) velocity was calculated for the study area. 3 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background The calculated seepage velocity for the saprolitic portion (including the PWR unit) of the uppermost aquifer in the vicinity of the assessment wells along the eastern side of Grassy Creek ranges from 0.014 to 0.305 ft/day, while the estimated groundwater flow rate of the upper limits of the fractured bedrock portion of the aquifer averaged slightly higher at 0.829 ft/day. Site Hydrogeologic History The following is a brief history of the sites monitoring wells and hydrogeologic findings from them. Vertical gradients between the saprolitic portion of the aquifer and the upper limits of fractured bedrock exhibit a downward component of flow, specifically at OW-7/7M, OW-7/7D, OW- 11/11M, and OW-12/12M. This downward gradient averages 0.004 feet per foot (ft/ft). On the other hand, there are strong upward vertical gradients measured in most of the deeper groundwater assessment wells completed within fractured bedrock. At the southern end of the plume, a downward gradient (at 0.001 ft/ft) is indicated between OW-7, completed within the saprolite, and OW-7D, completed within the upper limits of fractured bedrock. However, a strong upward gradient is present within the fractured bedrock. This can be seen by the gradients between the saprolite (OW-7) and the fractured bedrock at OW-7DA. An upward gradient of 0.004 ft/ft is measured from a depth between 111 and 114 feet bls, between OW-7 and OW- 7DA. Likewise, a strong upward gradient was also measured between 47 and 114 feet bls at OW-7D and OW-7DA at 0.007 ft/ft. At the center of the area of groundwater impacts, a strong upward gradient exists between the saprolite (OW-9) and the upper limits of fractured bedrock (at 65 feet bls) in OW-9D. Here, a gradient of 0.010 ft/ft was measured. This upward gradient becomes stronger with depth, increasing to 0.032 ft/ft between OW-9 and OW-9DA, completed to 85 feet bls in fractured bedrock. In OW-13D, completed to 115 feet bls, the upward gradient increases to 0.038 ft/ft. Furthermore, the upward vertical gradient within the fractured bedrock itself is also strong. A gradient of 0.066 ft/ft is measured between 65 and 115 feet bls within fractured bedrock at OW- 9D/13D, and a stronger gradient is even measured between 85 and 115 feet bls at 0.106 ft/ft at OW-9DA/13D. Gradients on the northern end of the area of impacts also exhibit similar patterns. There is an upward vertical gradient between the saprolite at OW-10 and the PWR zone at OW-10M. This gradient increases between OW-10 and OW-10D and is completed within the upper limits of fractured bedrock. A gradient of 0.008 ft/ft is measured between OW-10 and OW-10D. Beyond the small area of groundwater impacts to the north and south, nearly identical vertical gradients exist between the saprolite and PWR units, with 0.004 ft/ft downward at OW-11/11M and 0.003 ft/ft downward at OW-12/12M. As presented in the ACM, a rose diagram was produced using a fracture trace analysis of the straight-line segments of streams and tributary valleys. The resulting rose diagram shows a wide range of straight-line valley segment orientations. The strongest peak occurs at an orientation of between north 30 and 40 degrees east. Subsidiary peak orientations are located at north to north 10 degrees west, north 30 to 40 degrees west, and west to north 80 degrees west. The strongest null, at north 50 to 60 degrees west, is perpendicular to the strongest peak. 4 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan While fracture orientation is certainly important to groundwater flow in solid bedrock, the primary occurrence of shallow groundwater in the Piedmont is within the saprolite overlying bedrock. Here, groundwater flow occurs intergranularly, as compared to the flow of groundwater along fractures in bedrock. In this textural environment, the orientation of platey minerals, particularly micas that define foliation in the predecessor rock, has a stronger effect on groundwater flow than highly altered fracture remnants found in the saprolite. Considering this reality, a preliminary measurement of the orientation of remnant foliation has been made in the Landfill area. In the area where active soil cutting is taking place and where erosion has occurred along runoff channels, foliation and rare granitic veins or pegmatites are evident. Most of the observed foliation strikes between north and north 30 degrees east, and dips at about 20 to 60 degrees to the west. These strikes are subparallel to the dominant orientation of straight segments found in the vicinity. Water Quality Monitoring Program for Unit 1 Water quality at Unit 1 of the Landfill is monitored in accordance with the approved Revised Groundwater Monitoring Plan, dated March 1996, as modified by verbal and written communications between the City of Winston-Salem (City) and the NCDENR. Samples are collected from the following locations and analyzed in accordance with state approved laboratory methods. • Site Background Well – MW-1RR; • Closed Unlined Landfill – Performance wells (OW-3, OW-4, OW-10D, OW-12, OW-14D, and OW-17D), compliance wells (OW-6, OW-7DA, OW-10D, OW-11, and OW-12, OW- 13D), and two observation wells (OW-14D and OW-17D); • Subtitle D (“Piggyback”) Landfill – MW-6, MW-6D, MW-7, MW-8, MW-9, and MW-11. • Four surface water locations – NBC-1, NBC-2, SW-3, and SW-4. • One leachate sample. The updated water quality monitoring plan incorporates those changes previously approved by DENR at the Closed Unlined Landfill. These changes consist of (1) revising the monitoring parameters and Appendix II frequency; and (2) including the background well (MW-1RR) into the performance monitoring network at the Closed Unlined Landfill. Also, in accordance with NCDENR’s request, OW-7D will be sampled in the next semiannual sampling event. The sampling data will provide supplemental information in regards to the monitored natural attenuation status. Proposed Water Quality Monitoring Plan The proposed water quality monitoring program for Unit 1 of the Landfill includes select detection and assessment wells, four surface water sampling locations and one leachate collection point. The monitoring plan has been updated in accordance with the NCDENR letter of September 22, 2008 and March 4, 2010. The Plan update includes sample locations (groundwater, surface water and leachate), sample frequency, sample collection; preservation shipment; analytical procedures; chain of custody control; quality assurance and quality control. These components are designed to ensure monitoring results that provide an accurate 5 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan representation of water quality at the Landfill through effective detection monitoring and assessment of the efficacy of the MNA program. Sampling Locations The following paragraphs present the general rationale used to select groundwater (both detection and corrective action performance monitoring systems), surface water, and leachate sample locations. A substantial amount of geologic and hydrogeologic data has been developed at this site, much of which has been summarized in the Landfill permit documents. Well locations have been selected on the basis to provide water quality data from the uppermost aquifer beneath the facility, either in the unconsolidated saprolitic portion of the aquifer, as is the case for the Subtitle D Landfill, or from the fractured bedrock aquifer. The hydrogeologic and geologic characteristics of the facility and surrounding land, and the quantity, quality, and direction of groundwater flow were evaluated to determine the appropriate selection of monitoring wells. This evaluation considered site specific hydrogeologic information including aquifer thickness, groundwater flow rate, and groundwater flow direction, including seasonal and temporal fluctuations in groundwater flow. Also considered were unsaturated and saturated geologic units (including fill materials) overlying and comprising the uppermost aquifer; including but not limited to: thicknesses, stratigraphy, lithology, hydraulic conductivities, porosities and effective porosities, lithology of the aquifer and unsaturated zone; hydraulic conductivity of the aquifer and unsaturated zone; groundwater flow rates; minimum distance of travel; resource value of the aquifer; and nature, fate, and transport of any detected constituents. In addition, the distance of each proposed well relative to the waste unit (less than 250 feet) and the boundary of the property (50 feet or greater) was considered. Background Well Using the historical water table elevation data collected during multiple groundwater monitoring events at the facility, a background well was selected on the basis of hydraulic position in relation to the solid waste management units. The background well, MW-1RR, is hydraulically "upgradient" of the units and is located near former background monitoring wells OW-1 and OW-2. Historical and current water table elevation data indicates this well is consistently in an upgradient position. As discussed in detail as part of the Design Hydrogeologic Report, the uppermost aquifer at the Landfill is the saprolite derived from weathering of Ashe Formation rocks. The background well is completed in this uppermost aquifer, with a well screen that spans the water table, per North Carolina Department of Environment and Natural Resources. Please see Figure 1 for the locations of the background wells. Groundwater Monitoring Wells The proposed groundwater monitoring network for the Subtitle D cell includes background well MW-1RR and six side gradient or downgradient wells (MW-6, MW-6D, MW-7, MW-8, MW-9, MW-11). The proposed groundwater monitoring network for the unlined cell includes one background well (MW-1RR), and six performance wells (OW-3, OW-4, OW-10D, OW-12, OW- 14D, and OW-17D). and eight four complianceassessment wells (OW-3, OW-4, OW-6, OW- 6 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan 7DA, OW-10D, OW-11, OW-12, and OW-13D) . In addition, two observation wells (OW-14D and OW-17D) , located on the floodplain of Grassy Creek, are to be monitored as sentinel wells (Figure 1). Surface Water Monitoring Points Samples will be collected from four surface water sample locations (NBC-1, NBC-2, SW-3, and SW-4) to monitor the quality of surface water on the Landfill property. SW-3 and SW-4 are located along South Branch Creek. A surface water sample representing background water quality along the northern side of the Landfill will be collected from the upstream end of North Branch Creek at NBC-1. A downstream surface water sample, NBC-2, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. Likewise, a surface water sample representing background water quality along the southern side of the Landfill will be collected from the upstream end of South Branch Creek at SW-3. Finally, a downstream surface water sample, SW-4, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. The location of these surface water sampling locations can be seen on Figure 1. Leachate Sampling Locations Leachate samples will be collected for analysis to determine the concentration of constituents released from the waste (if any). One leachate sample will be collected from the tanks. Leachate from the cells in Unit 1 is combined in this location before being pumped to the tanks where it is held until its release to the local treatment plant. The leachate sample will be analyzed for BOD, COD, temperature, conductivity, phosphate, pH, ammonia, Total Suspended Solids, sulfates, nitrates, mercury and Appendix I parameters. Summary The Subtitle D landfill monitoring wells, the surface water locations, and the background well will remain unchanged in location and analytical parameters from the previous monitoring program. The current monitoring program including these locations is performing properly. Table 3-1 summarizes the location, sampling type, parameters, and basic monitoring function for each of the sampling locations included in this Plan and presents a new set of groundwater wells associated with the closed, unlined portion of the Landfill Unit 1. Based on the extent of the property owned by the Commission, the rate at which groundwater flows, and the stable nature of the groundwater impacts, data gathered from these locations will adequately monitor the facility and track the status of groundwater remediation. The physical location of each sampling site is identified on Figure 1. Data Collection A brief description of the sampling frequency, monitoring functions, and types of data that will be collected and analyzed during the performance of this Plan is provided in this section. Analytical Parameters and Frequency The analytical parameters for groundwater at the detection wells, surface water, and leachate samples associated with the Subtitle D cell will be consistent with the historical monitoring and 7 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan are unchanged except as described below. Monitoring wells at the lined landfill have been sampled for Appendix II parameters for four events due to detection of 1,1-DCE above the 2L Standard at MW-8. NCDENR has requested two additional consecutive events must be completed for each well with no groundwater standard exceedances before the site can revert to detection monitoring. The parameters for the MNA performance monitoring program have been slightly adjusted to reduce the performance monitoring parameters or the frequency of monitoring for the parameters in accordance with the NCDEDR letters of September 22, 2008 and March 4, 2010. The updated monitoring parameters will include Appendix II parameters, field parameters and laboratory parameters (Table 3-3). Performance monitoring includes analysis for Appendix II parameters at the closed unlined landfill which is conducted once every 2 years during the spring semiannual monitoring event. The two year frequency for Appendix II testing is in accordance with the NCDEDR letter dated March 4, 2010. Table 3-1 shows the frequency of monitoring at each well. This frequency will be sufficient to provide detection and performance monitoring considering: a. The extensive amount of down gradient property owned by the County; b. The existing impacts are limited to low level concentrations of VOC’sVOCs; and c. The incorporation of additional parameters into the monitoring program (e.g. chloride, sulfate, dissolved oxygen, ORP and methane gas – which are indicators of the source contributor and geochemical indicators of natural attenuation). Groundwater Level Measurements During each required water quality sampling event, static groundwater levels (and total well depth) will be obtained from the proposed groundwater compliance monitoring wells immediately prior to purging. An electronic water level meter capable of measuring differences in water levels of 0.01 feet will be used to obtain these measurements. All measurements will be obtained from a reference point at the top of each PVC well casing which has an elevation established by a North Carolina registered land surveyor. The horizontal position of each well will be established using North Carolina Plane Coordinates. These data will be used to calculate the volume of standing water in each well and will provide information concerning well integrity (e.g., identify the presence of excessive siltation and casing breaches). All measuring equipment will be decontaminated before use at each well as established by Environmental Protection Agency (EPA) standards. Groundwater Direction and Flow Measurements Groundwater elevations will be calculated for each monitoring well using surveyed top-of-casing elevations prepared by a North Carolina registered land surveyor. Calculated potentiometric surface elevations for each sampling event will be placed on a scaled base map of the facility beside each respective monitoring point and contoured to produce a water table potentiometric surface map depicting potential groundwater flow direction(s) across the site. In addition, the estimated groundwater flow velocity will be calculated for each water quality sampling event. Using the static water table potentiometric data, effective porosities, hydraulic 8 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan conductivity determined from slug tests, and the calculated hydraulic gradients for the respective sampling event, an estimated seepage (pore water) velocity will be calculated to continue to assess the potential for the migration of the low concentrations of VOC’sVOCs. 9 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 1 Summary of Monitoring Sample Locations and Functions Sample ID Location Sample Type Area Monitored Parameters Analyzed Monitoring Function Spring Event Fall Event Current Proposed Ground-water Surface Water Leachate Closed Subtitle D Closed Unlined Appendix MNA(3) Appendix Background Data Release Detection Performance Monitoring I II I II MW-1RR X X X X X(21) X X X X MW-6 X X X X X X(1) X MW-6D X X X X X X(1) X MW-7 X X X X X X(1) X MW-8 X X X X X X(1) X MW-9 X X X X X X(1) X MW-11 X X X X X X(1) X OW-3 X X X X X(21) X X X X OW-4 X X X X X(21) X X X X OW-6 X X X X X(2) X X X OW-7DA X X X X X(2) X X X OW-10D X X X X X(21) X X X X OW-11 X X X X X(2) X X X OW-12 X X X X X(21) X X X X OW-13D X X X X X(2) X X X OW-14D X X X X X(21) X X X X OW-17D X X X X X(21) X X X X NBC-1 X X X X NBC-2 X X X X SW-3 X X X X SW-4 X X X X Leachate Tank X X X X4 X (1) Appendix II monitoring for the closed Subtitle D site begins in Fall 2011 after the completion of background sampling for assessment monitoring (21) Samples will be monitored for Appendix II constituents every other spring monitoring event beginning in spring 2011. Detected Appendix II parameters will be monitored independently for 4 events at all wells at the unlined landfill. (32) Detail for performance monitoring is listed in Table 3-3. (43) Additional leachate parameters include BOD, COD, nitrate, sulfate, phosphate, TSS, ammonia and mercury. 10 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Well Construction Each downgradient well is installed with a screened interval of Schedule 40 PVC well screen with a 0.01-inch slotted opening. The construction of the groundwater monitoring wells is in general accordance with the North Carolina Well Construction Standards. Table 3-2 presents groundwater monitor well construction details. A schematic showing well-specific construction details for each well is provided in the Appendix of this Plan. Table 2 Monitoring Network Well Construction Details Well Grade Top of Casing Well Depth Screened Interval Screened Elevation Spring 2010 Water Levels (FT MSL) (FT MSL) (FT BLS) (FT MSL) Depth TOC FT MSL MW-1RR 893.60 896.82 60.0 45.0 - 60.0 848.6 - 833.6 41.08 855.74 MW-6 865.60 867.78 35.0 20.0 - 35.0 845.6 - 830.6 26.84 840.94 MW-6D 865.60 867.89 64.5 54.5 - 64.5 811.1 - 801.1 27.32 840.57 MW-7 843.10 845.33 25.0 10.0 - 25.0 833.1 - 818.1 14.88 830.45 MW-8 833.80 836.91 20.0 5.0 - 20.0 828.8 - 813.8 10.25 826.66 MW-9 840.40 842.31 30.0 15.0 - 30.0 825.4 - 810.4 20.58 821.73 MW-11 843.20 845.23 30.0 15.0 - 30.0 828.2 - 813.2 17.85 827.38 OW-3 817.75 820.13 16.0 6.0 - 16.0 811.8 - 801.8 8.53 811.60 OW-4 806.83 809.37 16.0 6.0 - 16.0 800.8 - 790.8 5.52 803.85 OW-6 824.74 827.12 27.0 12.0 - 27.0 812.7 - 797.7 16.28 810.84 OW-7DA 798.80 801.52 115.0 110.0 - 115.0 688.8 - 683.8 4.44 797.08 OW-10D 817.30 820.09 80.0 75.0 - 80.0 742.3 - 737.3 18.14 801.95 OW-11 804.47 806.69 16.0 6.0 - 16.0 798.5 - 788.5 2.68 804.01 OW-12 798.40 800.14 15.0 5.0 - 15.0 793.4 - 783.4 3.88 796.26 OW-13D 803.80 806.41 115.0 110.0 - 115.0 693.8 - 688.8 4.64 801.77 OW-14D 801.20 803.95 80.0 70.0 - 80.0 731.2 - 721.2 3.03 800.92 OW-17D 798.80 801.54 80.0 70.0 - 80.0 728.8 - 718.8 4.53 796.87 FT – Feet MSL – Mean Sea Level BLS – Below Land Surface TOC – Top of Casing Analytical Procedures Test Parameters and Methods Low-flow purging and sampling techniques are the preferred methodology for purging and sampling monitoring wells. Dedicated pumps will be utilized where available and otherwise decontaminated peristaltic or bladder pumps will be utilized. The pump will be positioned within the screened interval and will be pumped at such a rate that minimal drawdown will occur in the well. This is usually between 100 and 500 milliliters per minute (ml/min). 11 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 3 Updated MNA Monitoring Parameters and Methods Parameter Method or Equipment Used Monitoring Frequency Field Parameter Measurements Temperature Water quality meter Semiannual pH Water quality meter Semiannual Conductivity Water quality meter Semiannual Oxidation Reduction Potential (ORP) Water quality meter Semiannual Dissolved Oxygen (DO) Downhole or flow through cell meter Semiannual Turbidity turbidity meter Semiannual Water Elevation Electronic Water Level Indicator Semiannual Ferrous Iron SM 3500-Fe or Field Meter Semiannual Laboratory Analysis Hydrogen, sulfide, alkalinity, and volatile fatty acids Every 5 years from fall 2006 Methane, ethane, and ethane Every 3 years from fall 2006 Appendix I VOCs EPA Method 8260 Semiannual Appendix I Metals Varies Semiannual Appendix II Parameters* Once Every Two Years Nitrate-N EPA 352.1/353.2/353.3 Semiannual Sulfate EPA 375.4/375.2/300.0 Semiannual Chloride EPA 325.2/325.3/310.0 Semiannual Total Organic Carbon SM 5310B/310.2 Semiannual Note: * Four independent samples will be analyzed for any detected Appendix II Parameter from all Performance wells to establish background levels for the compound Once drawdown has stabilized, a flow through cell meter will be connected to the water discharge outlet to record field measurements [pH, temperature, specific conductance, dissolved oxygen (DO), salinity, and oxidation reduction potential (ORP)] to determine when a representative sample can be collected. These measurements will be obtained from a field- calibrated instrument in accordance with the manufacturer’s specifications and industry standards. The flow cell meter will log the geochemical changes of the purge water and signal when they become stabilized. Well purging efforts will continue until the following stabilized conditions occur: pH ±0.2 units, DO ±0.2 mg/l (or ± 20% whichever is greater), specific conductance ±5%, ORP ±10 millivolts (note this compound is optional and is not required). At that time, the flow cell will be disconnected allowing the water quality samples to be collected directly from the discharge tube under low-flow conditions (<100 ml/min). The parameters to be incorporated into the MNA performance-monitoring program have been selected to track contaminant concentrations (including daughter products) and key indicators of natural attenuation processes, and detect any new potential impacts. 12 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Field measured parameters include pH, specific conductivity, temperature, dissolved oxygen (DO), and oxidation reduction potential (ORP) which serve as indicators of natural attenuation processes, as well as indicators of general water quality. Table 3-3 presents the performance monitoring parameters and methods. Sample Preservation and Shipment All samples will be collected using the containers, preservatives, and holding times appropriate for each respective parameter being analyzed. The proper chain of custody and sample blank (trip blank and equipment blank) procedures will also be followed accordingly. In addition to providing evidence of attenuation, data (groundwater elevation measurements) will be collected to determine the direction and rate of any contaminant migration. All samples will be analyzed for the targeted parameters by a laboratory certified by the State of North Carolina. Surface water samples will be collected according to the “Environmental Investigations Standard Operating Procedures and Quality Assurance Manual”, May 1996, Sections 5 and 10. Samples will be collected directly into the sample containers facing upstream at mid-depth at the center of the channel (except VOCs). Surface water samples for VOC analysis will be collected using decontaminated glass lab containers and transferred to 40 ml vials leaving no headspace. Care will be taken not to disturb the bottom sediment and not to displace the preservative from a pre-preserved sample container. The area of the surface water samples will be selected according to the location of the greatest degree of cross-sectional homogeneity. If available, the surface water sample locations will be selected immediately downstream of riffle areas to ensure good vertical mixing. Tributaries will be sampled as near the mouth as feasible. Temperature, pH, turbidity, and conductivity will be measured at each surface water sample location. Surface water samples will only be collected if flowing water is noted at the time of sampling (i.e. not stagnant water). Reporting The data from each semiannual sampling event will be evaluated and reported to the NCDENR NCDEQ along with the regular semiannual groundwater reports. At the end of a two-year period, the groundwater remediation status will be re-evaluated. 13 Landfill Gas Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised May June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Contents Introduction ................................................................................................................................ 1 Background Information ............................................................................................................. 2 General .................................................................................................................................. 2 Site Information ...................................................................................................................... 2 Landfill Gas Overview & Regulatory Action Levels ..................................................................... 3 Landfill Gas Monitoring .............................................................................................................. 4 Proposed Landfill Gas Monitoring Procedure.......................................................................... 4 Permanent Monitoring Station Design and Installation ........................................................ 4 Gas Migration Monitoring ...................................................................................................11 Reporting of Data and Record Keeping ..............................................................................17 Continuous Monitoring of On-Site Structures .....................................................................17 Schedule for Installation of Monitoring Elements ...................................................................17 Maintenance and Calibration of Monitoring Elements ............................................................18 Maintenance of Permanent Monitoring Stations .................................................................18 Calibration of Portable Monitoring Instruments ...................................................................18 Contingency Plan ......................................................................................................................19 Contingency Plan Guidelines .................................................................................................19 Contingency Plan - On-site Structures ...................................................................................19 Immediate Action ...............................................................................................................19 Action within 7 Days ...........................................................................................................20 Action within 60 Days .........................................................................................................20 Contingency Plan - Facility Property Boundary ......................................................................20 Immediate Action ...............................................................................................................20 Action within 7 Days ...........................................................................................................20 Action within 60 Days .........................................................................................................21 LFG Control System Installation and Monitoring .......................................................................23 Passive Gas Control System .................................................................................................23 Surface Monitoring and Observations ................................................................................23 Subsurface Pressure .........................................................................................................23 Proximity ............................................................................................................................23 Active Gas Control System ....................................................................................................24 Gas Collection System .......................................................................................................24 i City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Gas Utilization or Control System ......................................................................................24 Safety .......................................................................................................................................25 Tables Table 1 Compliance Levels for Methane ................................................................................... 3 Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ........................................... 4 Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 ........................................ 4 Table 4 Contingency Plan Contacts .........................................................................................19 Table 1 Compliance Levels for Methane ................................................................................... 3 Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ..........................................54 Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 .......................................54 Table 4 Contingency Plan Contacts ..................................................................................... 1513 Figures Figure 1 Drawing 00C-02 Gas Monitoring Wells ........................................................................ 6 Figure 2 Typical Methane Probe Construction..........................................................................10 Figure 3 Groundwater Surface Contour Map ............................................................................13 Figure 1 Drawing 00C-02 Gas Monitoring Wells ........................................................................65 Figure 2 Typical Methane Probe Construction...........................................................................87 Figure 3 Groundwater Surface Contour Map ........................................................................... 119 Appendices Appendix A - Field Data Form Appendix B – Boring Logs ii City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Introduction Introduction The purpose of this Landfill Gas Monitoring Plan (LGMP) is to provide a management practice for the monitoring and control of landfill gas generated by the Hanes Mill Road Landfill. Following approval of this LGMP by the North Carolina Department of Environmental Quality and Natural Resources (NCDEQ) Division of Waste Management (DWM), a routine methane monitoring program will be implemented at the landfill. Once final closure of the unitfacility is complete, the monitoring program will continue in accordance with NcNC regulation, 15A NCAC 13B .1627 (d). At the present time, this term is for a minimum of 30 years. Following approval, this plan will be placed in the landfill operating record and shall remain open for revisions throughout the active life of the landfill, as well as after landfill closure is complete. All changes to this plan will be submitted to NCDEQ DWM as they are implemented. 1 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Background Information Background Information General The Hanes Landfill is located off Hanes Mill Road approximately five miles north of the City of Winston-Salem, North Carolina (the City) and is operated under North Carolina NCDEQ DWM Permit No. 34-02.The facility consists of two major unitsareas: the original landfill unit consisting of the unlined and “piggyback” unitarea, which closed in 2005 is now closed, and an expansion area which is currently active. The closed landfill contains an unlined and a lined MSW unit and is located on approximately 181 acres. The landfill expansion area occupies approximately 90 acres to the west of Grassy Creek and the Norfolk Southern Railroad. Phase 1 of the expansion area was permitted, constructed, and begin accepting waste in May 2005. The proposed Phase 2 of the expansion area is located immediately north of Phase 1 and consists of approximately 22 acres. Filling at the landfill will be conducted by the area method in which the waste will be placed in lifts of approximately 10 feet in height which is then covered with soil (or approved alternative cover) on a daily basis. Site Information Land use is primarily limited to residential development to the north and west of the landfill expansion area. To the east of the area are the Norfolk Southern Railroad line, the closed landfill area, and a combination of commercial and residential developments. The headquarters for Sara-Lee Corporation is located along the southern edge of the landfill expansion area; land to the south is also being used for other commercial endeavors, as well as residential development. 2 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Overview & Regulatory Action Levels Landfill Gas Overview & Regulatory Action Levels One of the byproducts of landfilling municipal solid waste is landfill gas which is generated by the anaerobic decomposition of waste within the landfill. Landfill gas typically consists of methane (CH4) and carbon dioxide (CO2), with trace amounts of oxygen (O2), water (H2O), nitrogen (N2), hydrogen sulfide (H2S), and other gases. The amount and rate of generation of landfill gas is affected by several factors, including the following. • Total refuse tonnage in-place. • Moisture content of the refuse. • Age of the refuse. • Organic composition and pH value of the refuse. • Method and degree of compaction of the refuse. • Type and amount of cover material used. The concentration of the landfill gas varies according to site-specific conditions; however, landfill gas compositions of 30-53 percent methane (CH4) and 34-51 percent carbon dioxide (CO2) are common. In addition to being a potent greenhouse gas, tThe primary health and safety concern with landfill gas in the immediate area of the landfill is the explosive characteristic of methane. Methane concentrations in excess betweenof 5 and 15 percent by volume in air (5% is referred to as the “Lower Explosive Limit” or LEL, and 15% is referred to as the Upper Explosive Limit or UEL) are able to create an explosion hazard and can also propagate a flame, thus creating an explosion hazard. The Upper Explosive Limit (UEL) for methane is 15 percent by volume in air. Landfill gas can travel in all directions, taking the path of least resistance. Landfill gas moves from areas of higher concentrations to areas of lower concentrations (diffusion), or from higher gas pressure zones to lower gas pressure zones (convection). Subsurface geologic and hydrogeologic conditions contribute greatly to the potential for gas migration. When landfill gas migration is taking place, on-site and nearby structures are at risk of receiving migrating gas due to confined spaces in or under the buildings. Landfill gas can enter buildings through cracks in the foundation or subsurface utility services. Lack of ventilation may result in the buildup of methane concentrations to explosive limits. In an effort to eliminate the potential hazards associated with the migration of landfill gas, NCDEQ has promulgated regulations (15A NCAC 13B .1626 (4)) , which require owners and/or operators of all municipal solid waste landfill facilities (MSWLF) to monitor methane at the facility property boundary and on-site structures. Table 3-1 below provides the present regulatory limits for methane at MSWLF sites. Table 1 Compliance Levels for Methane Location Lower Explosive Limit (% LEL) Maximum Methane Concentration in Air Property Boundary 100% 5% Facility Structures 25% 1.25% 3 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Landfill Gas Monitoring Proposed Landfill Gas Monitoring Procedure To provide a means of monitoring methane gas at the landfill, permanent gas migration monitoring stations have been installed along the perimeter of the active and closed landfill areas. These stations are monitored on a quarterly basis. Additional stations will be installed in the Phase 2 expansion area as needed. Permanent Monitoring Station Design and Installation Permanent monitoring stations have been installed around the active and closed landfill. All the wells are for detection monitoring. Figure 1, Drawingdrawing 00C-02 Gas Management Plan, shows the monitoring wells at the landfill. ACTIVE LANDFILL EXISTING STATIONS Eight permanent monitoring stations (MM-1 through MM-8) have been installed along the permit boundary for Phase 1 of the landfill expansion at not more than 500-foot intervals (see Drawing C-8). Four Three additional wells will have been installed and a fourth is in the process of being installed for Phase 2 prior to waste placement. The well locations were placed between the permitted waste boundary and property lines. No wells are shown between the active landfill and Grassy Creek since this is interior to the property line and Grassy Creek acts as a cut-off feature. The following tables summarize the existing and proposed installation details for each gas probe. Figure 4-12 shows the typical construction details for a permanent methane monitoring probe. Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 Station ID Number Total Depth Screened Interval MM-1 7 Feet 3 - 7 Feet MM-2 14 Feet 2 - 14 Feet MM-3 14 Feet 2 - 14 Feet MM-4 2.5 Feet 1.5 - 2.5 Feet MM-5 4 Feet 2 - 4 Feet MM-6 5 Feet 2 - 5 Feet MM-7 5 Feet 2 - 5 Feet MM-8 4 Feet 2 - 5 Feet MM 9 7 Feet 2 – 7 Feet MM 10 10 Feet 2 – 10 Feet MM 11 40 Feet 2 – 40 Feet MM-12 To be installed Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 Station ID Number Total Depth Screened Interval MM-12 45 Feet 2 - 45 Feet Notes: (1) See boring logs for subsurface lithology (Appendix B) (2) See potentiometric surface map for depth to groundwater 4 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 5 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Replace this page with (11x17) Figure 1 Drawing 00C-02 Gas Monitoring Wells 6 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Formatted 7 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 8 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 9 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Figure 2 Typical Methane Probe Construction 10 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Station depths were based on geological formations logged during the installation of the nearest ground-water monitoring wells, the proposed depth of waste, and the recorded seasonal high ground-water elevations. All existing stations were installed with screens beginning at the elevation of the bottom of waste, or slightly above the top of the seasonal low water table (whichever is higher) and extending upward to approximately 2 feet below grade. Future monitoring stations will be installed using the same criteria. The final design depths of the future stations will be determined in the field during borehole installation. Refer to See the potentiometric map Figure 3, Groundwater Surface Contour Map, for the depth to groundwater. CLOSED LANDFILL EXISTING STATIONS Twenty-two permanent monitoring stations (MM-B through MM-K, MM-P through MM-U, MM-W through MM-Z, and MM-AA through MM-BB) have been installed along the boundary for the closed landfill. ACTIVE LANDFILL FUTURE STATIONS The gas monitoring stations for Phase 2 of the active landfill will be installed using 4.25-inch inside diameter (ID) hollow stem augers. Once at the desired depth, a 1-inch, Schedule 40 PVC gas probe will be inserted through the center of the augers. Each probe will be constructed with flush-threaded joints with a screened interval of 0.010-inch, factory-slotted well screen. Coarse- grained silica gravel will be placed around the screen interval by gravity settling. The gravel pack will extend to a minimum of 6 inches above the top of the screen. A 6-inch minimum bentonite seal will be placed immediately above the gravel pack. The remaining probe annulus will be sealed to surface grade using a Portland Type I cement mixture. Each probe station will be protected above grade by a 4-inch square steel locked well box secured in place with a 2- foot by 2-foot concrete pad. The top of each well probe will be fitted with a laboratory-type stop- cock valve for gas sample collection. The outside of each station will be fitted with an identification tag indicating the station number, installation date, driller name and registration, completion depth, and screened interval. Reading Gas Migration Monitoring Stations Reading of the permanent monitoring stations and on site structures will be conducted on a quarterly schedule. As per existing regulations, Tthe monitoring frequency of individual stations may be increased if methane is detected above the LEL. Sampling procedure will follow the manufacturer’s instructions. All perimeter gas stations shall be monitored for the following parameters. • Combustible Gas (methane) - with a Landtec GEM 2000 (or equivalent).The station shall be sufficiently evacuated with the sample pump so that methane concentrations are constant for at least 30 seconds. The large scale (0-100 percent methane-in-air) shall be used first. If readings are below 5 percent, the reading will be obtained using the smaller (0-5 percent methane-in-air) scale. Information from the monitoring will be recorded on the field data form (Appendix A). Any readings recorded at or above the LEL for methane will be immediately verified and reported as described in Section 5.0 of this plan. 11 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 12 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Replace this page with (11x17) Figure 3 Groundwater Surface Contour Map 13 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 14 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 15 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring 16 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Reporting of Data and Record Keeping All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix A). Copies of the completed quarterly reports, including the original completed field data forms, will be kept on-site in the Landfill Operating Record for a minimum of two years. A separate calibration log for the on-site instrument will be kept on-site and will contain the following information. • Date and time of calibration. • Name of person calibrating. • Serial number and model number of instrument. • Type of calibration. • Results of calibration. Continuous Monitoring of On-Site Structures All Select on-site buildings will be equipped with a Sierra Monitor 2001 series (or equivalent) continuous monitoring device to detect combustible gas concentrations that may accumulate inside the structures. Continuous monitoring of the buildings may be supplemented with quarterly monitoring using a portable instrument. The Sierra Monitor 2001 series is rated to detect a wide range of combustible gases and has a methane detection range of 500 to 10,000 parts per million (ppm) (.05 to 1.0 percent methane- in-air). The monitor should be installed in an area of the structure where methane gas is most likely to accumulate. Any verifiable detection of methane in the structures will be addressed and reported in accordance with Section 5.0 of this LGMP. Reporting of Data and Record Keeping All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix A). Copies of the completed quarterly reports, including the original completed field data forms, will be kept on-site in the Landfill Operating Record for a minimum of two years. A separate calibration log for the on-site instrument will be kept on-site and will contain the following information. • Date and time of calibration. • Name of person calibrating. • Serial number and model number of instrument. • Type of calibration. • Results of calibration. Schedule for Installation of Monitoring Elements The permanent stations will be installed around Phase 2 of the active landfill after the City receives NCDEQ’s approval of this landfill gas management plan and before waste placement in Phase 2 of the active landfill. When the City determines that additional permanent monitoring stations are needed, this station will be installed and a notification will be submitted to the 17 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring NCDEQ DWM showing station design, location, and installation schedule. As-built documentation will be submitted to the NCDEQ DWM after installation. Maintenance and Calibration of Monitoring Elements The City conducts the following maintenance schedule and calibration procedures for the gas monitoring elements at the landfill. Training of personnel is conducted when necessary. Monitoring of the Phase 2 landfill area will be incorporated into this schedule. Maintenance of Permanent Monitoring Stations A visual inspection of the permanent stations will be conducted quarterly in conjunction with the monitoring events. The inspection schedule will increase with any increases in the monitoring schedule. The condition of following elements will be inspected. • Station label. • Protective casing and concrete pad. • Lock. • Station surroundings including standing water and vegetation. Any abnormalities regarding the condition of the station will be noted on the field log and immediately addressed. Calibration of Portable Monitoring Instruments CONTINUOUS MONITORING DEVICES Continuous monitoring devices will be maintained and calibrated according to the manufacturers’ recommendations. Maintenance and calibration will be conducted quarterly and will include the following tasks. • Verification of power to the monitor. • Ensuring that there is no interference of air flow to the monitor. • Exposing the sensor to a sample of calibration gas per the manufacturer's recommended procedure to verify that the monitor is calibrated correctly. PORTABLE MONITORING INSTRUMENTS Portable monitoring instruments such as the Landtec GEM 2000 will be maintained and calibrated according to the manufacturer's recommended procedure. For a detailed description of the maintenance and calibration procedures, the instruction manual should be consulted. 18 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Contingency Plan The City will implement the following contingency plan if the landfill gas readings at any monitoring location exceed the limits set by the stateregulations (see Section 3.0 of this plan). Contingency Plan Guidelines If allowable maximum limits for methane gas are exceeded at the facility property boundary or in on-site structures, the City will take the following steps. Step 1: Immediately take all necessary steps to ensure protection of human health and notify NCDEQ. Step 2: Within seven days of detection, place the methane gas levels detected and a description of the steps taken to protect human health in the operating record. Step 3: Within 60 days of detection, develop and implement a remediation plan that describes the nature and extent of the problem and proposed remedy for the methane gas releases, place a copy of the plan in the operating record and notify NCDEQ that the plan has been implemented. Consistent with the above requirements, notifications will be made either in person or by telephone followed by a facsimile transmission or letter. The City will also contact the following agencies or personnel as necessary. Table 4 Contingency Plan Contacts Agency or Personnel Contact Telephone Number City of Winston-Salem Solid Waste Administrator 336-727-7310 City of Winston-Salem Solid Waste Engineer 336-734-1506 399-5051 City of Winston-Salem Landfill Operation SuperintendentManager 336-399-5053430-6172 NCDEQ – Emergency Notification Environmental Specialist 336-771-5000776- 9672 Fire Department -- 336-727-800084 or 336-773-7900 Contingency Plan - On-site Structures The following contingency plan for responding to the detection of excessive methane gas quantities detected in all onsite buildings will be implemented by the City. Immediate Action • The affected building(s) would be vacated for a period of time determined by the appropriate emergency officials and all necessary steps will be taken to ensure protection of human health. • The landfill operations superintendentmanager, the occupants of the building(s), and the personnel listed in Section 5.1 will be contacted. • Notify NCDEQ. 19 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan • Following the evacuation, the building(s) will be monitored by City personnel to determine the extent and source of the methane. Remedial actions such as sealing cracks or connections would be taken as necessary. Action within 7 Days The landfill manager willstaff will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.2.1 of this LGMP. Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long term remedial action(s). IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the Plan has been implemented. Contingency Plan - Facility Property Boundary The City's proposed contingency plan for responding to excessive methane gas quantities at the facility property boundary is provided below. Immediate Action • Landfill personnel will be directed away from the affected area and all necessary steps will be taken to ensure protection of human health. • The affected area will be monitored daily for a period of time to confirm the methane concentration. • If monitoring reports are positive, areas adjacent to the affected zone (including the property line, utility trenches, and off-site buildings and structures) shall be monitored or screened by designated personnel. • If the methane gas quantities exceed the LEL at the facility boundary, the landfill manager and the personnel listed in Section 5.1 of this plan, may be contacted. • Notify NCDEQ. Action within 7 Days The landfill manager will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.3.1 of this LGMP. 20 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long-term remedial action(s) such as installation of passive or active gas control system. A copy of the LGMP will also be placed in the landfill operating record for the facility. NCDEQ will be notified that the remediation plan has been implemented. BAR-HOLE PROBE INSTALLATION AND MONITORING PROCEDURE Bar-hole probes may be temporarily installed as a remediation plan and monitored along the perimeter boundary of the landfill. Bar-hole probes may be used for identifying and tracking methane migration plumes, as described in Section 5.0, and as a substitute monitoring method for damaged or malfunctioning permanent probes. Prior to conducting bar-hole probing, the area will be checked for any subsurface utilities, conduits, or pipelines. If water or mud covers the desired probe location, then the probe will be offset to a nearby dry portion of the permit boundary or temporarily eliminated from the monitoring round. All precautions shall be taken to eliminate the introduction of moisture into the monitoring instrument. Any abnormalities in the probe location will be noted on the field data form (refer to Appendix A). The bar-hole procedure will involve pushing a 1/2-to 3/4-inch diameter metal rod a minimum of 2-3 feet into the subsurface soils. Upon removal of the metal rod, a probe connected to Landtec GEM 2000 or equivalent will be immediately inserted into the hole and sealed to minimize air infiltration into the sample. A measurement of the sample, along with other pertinent data, will be taken and recorded on the field data form located in Appendix A. Readings from the probe hole will be taken first with the instrument in the “HIGH” or 0-100 percent methane-in-air range. If a reading above 5 percent cannot be maintained during evacuation for at least 30 seconds, then the measurement shall be repeated with the instrument in the “LOW” or 0-5 percent methane-in-air (0-100 percent of the LEL) range. Upon completion of the monitoring, the probe hole will be backfilled with native soil. If concentrations of methane are measured at or above the LEL, additional bar-hole probes will be installed to assess the lateral extent of the migration. The additional probes will be placed in a radial pattern starting at the initial probe location and working in 5-foot increments outward. The pattern will continue until readings of 0 percent methane are obtained. Information from this monitoring procedure will be recorded on graph paper to determine the extent of the migration. The information will be submitted to NCDEQ in the Semiannual Ground-Water Monitoring Report. If it is determined that off-site migration exists above the LEL, the information, along with any proposed mitigation measures, will be submitted in accordance with Section 5.0 of this LGMP. 21 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan The bar-hole probe equipment will be maintained between monitoring events. Maintenance associated with the bar-hole probe monitoring includes ensuring plunger bar is clean and free of damage. IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the remediation plan has been implemented. 22 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring LFG Control System Installation and Monitoring If necessary, a gas control system can be installed as a mitigation measure to prevent the off- site migration of landfill gas. The City understands that the installation of an active gas collection system may be required at the landfill expansion area to control non-methane organic carbon (NMOC) emissions. Any active gas collection system required will be integrated into this LGMP after it is installed. The results of any landfill gas monitoring event, described in Section 4.0 of this LGMP, will be presented to NCDEQ for review. If a LFG control system is required at the landfill to control or prevent off-site gas migration, the City can pursue one of the following two alternatives. • Passive Gas Control System, or • Active Gas Control System. Passive Gas Control System Passive vents can release some of the pressure of landfill gas within the waste, thus reducing the amount of localized gas migration. A typical passive gas control system utilizes gas "vents" that are simple in design and require low maintenance. A passive gas control system has been proposed for implementation during the closure of the landfill. A passive gas control system consists of gas vents installed in the refuse. The passive vents will vent freely into the atmosphere, thereby reducing subsurface pressure and controlling local lateral migration of the gas. The vent wells should be designed and spaced so that the system could be converted into an active gas control system, if necessary, in the future (see Section 6.2). The locations of the passive vents are determined using any one, or a combination, of the following three methods. Surface Monitoring and Observations Observations of the surface conditions at the site can aid in determining the best location for passive vents. Venting cracks, stressed vegetation, and odors are all indicative of gas migrating through the soil cover. In addition, monitoring of the surface may be conducted to locate less visible emission sources. Subsurface Pressure If feasible, subsurface soil pressure measurements can be taken within the landfill permit limits to determine areas of increased pressure. Gas vents can then be installed to release the pressure. Proximity Passive vents should be installed in close proximity to the area of concern. One or more vents can be installed next to the permanent station, bar-hole probe, or facility structure that contained methane above the designated limits. Additional vents may be installed until the area of concern is mitigated. 23 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring The passive gas system performance monitoring is conducted on a quarterly basis and increased to a monthly basis if necessary. Monitoring methods are described in Section 4.0 of this Plan. Active Gas Control System An active gas control system consists of a collection system plus a utilization or control system. The design of the system components depends upon the site-specific conditions. The main components of an active gas collection system are the gas collection system and the gas utilization or control system. Gas Collection System The main components of a gas collection system are gas wells, gas collection headers with appropriate fittings and supports, and the moisture/condensate removal and collection system. It is anticipated that vertical wells will be used rather than horizontal wells. Horizontal wells require installation during filling, while vertical wells may be installed at any time. The locations of the vertical wells will be determined in a manner similar to locating the passive gas control vent system. Gas Utilization or Control System Two common types of gas utilization or control systems are LFG flare systems and cogeneration systems. Selection of the system will depend on several factors including LFG flow rates, quality, and cost-benefit analysis. Measurements will be performed to determine whether the methane can be economically collected and utilized as a fuel source. If economical, a cogeneration system may be installed. Typically, a cogeneration system includes a gas treatment plant, gas turbine(s) or internal combustion engine(s) and generating set(s), and other ancillary equipment. If the methane cannot be collected and utilized economically, a system consisting of multiple open gas flare units will be installed. A flare system will typically consist of gas blower(s), flares, moisture separators, and a detailed safety system. 24 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety Safety Prior to beginning a monitoring procedure, the landfill technician must understand the potential dangers associated with landfill gas. Not only is landfill gas explosive, it can also present the following other hazards. • Landfill gas may cause asphyxiation through oxygen displacement. Proper procedures must be followed when entering confined spaces which may be potential receptors of migrating landfill gas. • Some of the possible trace contaminants associated with landfill gas, such as hydrogen sulfide (H2S), are extremely toxic. Technicians must be trained in the indicators of H2S such as its recognizable odor (rotten egg) at low concentrations. At a minimum, the following items should be addressed by the technician, in addition to any site- specific safety procedures to reduce the chance of injury. • Be aware of the hazards of landfill gas as mentioned above. • Practice confined space entry procedures when entering structures that have been evacuated due to the possible presence of landfill gas in confined space. • Always practice the “buddy” system (i.e., work with a partner who remains outside of the area of possible exposure) when monitoring for landfill gas. • Know where all firefighting equipment (i.e., extinguishers, hoses, etc.) is stored and ensure that it is well maintained. • Determine whether additional personal safety equipment is necessary. • Do not smoke or allow others nearby to smoke while monitoring for landfill gas, or at any time when near landfill waste. • Know how the monitoring instruments work and how to operate and calibrate them properly. • Determine where all nearby subsurface utilities are prior to bar-hole probing. • Do not use odor as a primary indicator of landfill gas migration. • Inform the landfill manager or your supervisor of any possible hazards, no matter how small they may appear. 25 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety This page intentionally left blank. 26 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices A Appendix A - Field Data Form City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices B Appendix B – Boring Logs City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. Operations Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents Contents Introduction ................................................................................................................................ 1 Standard Operating Procedures ................................................................................................. 1 Waste Screening Programs ....................................................................................................... 1 Waste Receiving and Inspection............................................................................................. 1 Waste Determination Process ................................................................................................ 2 Prohibited Waste Types ......................................................................................................... 2 Hazardous Waste Contingency Plan ...................................................................................... 3 Waste Disposal .......................................................................................................................... 4 Placement of Initial Lift ........................................................................................................... 4 General Procedures ............................................................................................................... 4 Equipment Operations within the Landfill Cell ......................................................................... 5 Procedures for Stormwater Separation ................................................................................... 5 Alternative Daily Cover ............................................................................................................... 6 Concrete, Asphalt, and Brick Operations .................................................................................... 7 Explosive Gases Control ............................................................................................................ 7 Methane Monitoring Well Placement ...................................................................................... 7 Methane Monitoring Program ................................................................................................. 7 Sampling and Analysis Procedures ........................................................................................ 8 Emergency Response Plan .................................................................................................... 8 Sedimentation and Erosion Control ............................................................................................ 8 Leachate Management .............................................................................................................. 9 General .................................................................................................................................. 9 Leachate Pretreatment and Discharge ..................................................................................12 Separation of Stormwater ......................................................................................................12 Leachate Quality Sampling ....................................................................................................12 Leachate Contingency Plan ...................................................................................................12 Air Quality Control .....................................................................................................................13 Access and Safety Requirements .............................................................................................13 Spreading and Compacting Program ........................................................................................13 Record Keeping Program ..........................................................................................................14 i City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Introduction Introduction The purpose of this section is to identify protocols for the overall operation and maintenance of the landfill expansion area, which is owned and operated by the City. This plan has been prepared in accordance with appropriate NCDEQ .1600 rules and provides details of the procedures and policies, which shall be implemented throughout the life of the City’s landfill expansion area. Refer to the Phase 2 Application to Construct drawings for an illustration of the existing conditions of the landfill expansion (including known limits of existing and previous disposal areas, and buffer zones); the fill phasing (including the progression of operation including daily operation, transition contours, and final contours); and proposed final contours and erosion control plans (including storm water control, and stockpile and borrow operations). Standard Operating Procedures Hours and Days of Operation The landfill is open for operation between the hours of 7:00 AM and 4:30 PM, Monday through Friday, and from 8:00 AM to noon on Saturday. The landfill is normally closed on Sundays except where prior permission has been given to receive waste for special instances such as a natural disaster. The landfill is closed on Thanksgiving Day and Christmas Day. The landfill is open from 7:00 AM to 3:00 PM on New Year’s Day, Martin Luther King Jr. Day, Good Friday, Memorial Day, Independence Day, and Labor Day. It is anticipated that this schedule will continue, however operational hours and holidays may change as the need arises. Waste Screening Programs In order to reduce the risk of prohibited wastes entering the landfill facility, waste screening programs have been implemented at the existing landfill. Waste received at both the scalehouse entrance and waste taken to the working face is inspected by trained personnel. These individuals have been trained to spot unauthorized waste, including: liquids, sludges, drums or barrels, and other banned wastes. Programs for visual characteristics of prohibited wastes are an ongoing part of the existing landfill operation. These programs are implemented in accordance with Rule .1626 Part (1)(f). Waste Receiving and Inspection All vehicles must stop at the scalehouse located at the entrance of the landfill facility. Refuse transportation vehicles are weighed and the content of the load assessed. The scale attendant(s) requests from the driver of the vehicle entering the landfill a description of the waste it is carrying to ensure that unacceptable waste is not allowed into the landfill. The attendant(s) then visually checks the vehicle as it crosses the scale. Signs informing users of the acceptable and unacceptable types of waste are conspicuously posted on the landfill property. The Hanes Mill Road Landfill also has a random waste inspection program. Vehicles under this program are selected at random. At least 1 percent of the waste stream (by weight) will be 1 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs inspected under this program looking for liquid waste, hazardous waste, regulated PCB waste, and other banned items. Selected vehicles waste is carefully spread using suitable equipment. An operator trained to identify wastes that are unacceptable inspects the waste discharged at the screening site. If unacceptable waste is found, the waste will be isolated and secured for removal. Unacceptable wastes out of the permitted service area will be reported to the NCDEQ Division of Solid Waste Management within 24 hours of attempted disposal. The hauler is responsible for removing unacceptable waste from the landfill property. If no unacceptable waste is found, the load will be pushed to the working face and incorporated with the daily waste. Sludges can be accepted at the active landfill, if the sludges pass the paint filter test and the hauler has documentation that the sludge is non-hazardous as defined by NC law. For each vehicle screened, a random waste screening inspection form will be filled out and will be kept on-site. The inspection form should include the following information. • The date and times wastes were received for inspection. • Source and type of wastes. • Vehicle and driver identification. • All observations made by the inspector. • Final disposition of waste after inspection. Waste Determination Process In accordance with 15A NCAC 13B .1626 (f), the Hanes Mill Road Landfill requires documentation and prior approval in order to dispose of special wastes such as contaminated soils, sludge, ash, sandblasting waste, and filter press residue, etc. The main intent of the special waste program is to ensure that the landfill does not receive hazardous or liquid waste as defined by North Carolina law/regulations. Before special wastes can be disposed at the landfill, a Special Waste Disposal Application must be executed in its entirety, submitted to and reviewed/approved by the City-County Utility Solid Waste Administration. Approval for disposal must be obtained before attempting to dispose of special wastes. Prohibited Waste Types At the present time, the following wastes are prohibited from disposal within the MSW landfill unit. • Whole scrap tires • Used oil • White goods • Lead acid batteries • Yard trash • Regulated asbestos waste (friable) • Aluminum cans 2 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Screening Programs • Antifreeze • Beverage containers that are required to be recycled under G.S. 18B-1006.1 • Motor vehicle oil filters • Certain rigid plastic containers • Wooden pallets • Discarded computer equipment Does not include mice and keyboards • Certain televisions • Oyster shells Although friable asbestos waste is prohibited, nonfriable asbestos waste such as shingles are accepted and treated as MSW. In the event that friable asbestos is delivered to the site, it will be treated as unacceptable waste and dealt with in a manner outlined in Section 5.3.3. In addition, operating criteria prohibit other materials from disposal at the MSW landfill unit. These criteria address the following types of waste. • Hazardous waste as defined by NC law. • Polychlorinated biphenyls (PCB) wastes as defined in 40 CFR 761. • Bulk or non-containerized liquid wastes unless the waste is household waste other than septic waste and waste oil; or the waste is leachate or gas condensate derived from the MSW landfill unit, whether it is a new or existing MSW landfill unit or lateral expansion, is designed with a composite liner and leachate collection system. • Containers holding liquid wastes unless the container is a small container similar in size to that normally found in household waste; the container is designed to hold liquids for use other than storage; or the waste is household waste. • Spoiled foods, animal carcasses, and other animal wastes fall into the category of special handling. The generator of the material should call in advance to the landfill, and a determination will be made as to whether or not the waste will be accepted. If the waste is approved, the generator will present the waste at a predetermined time, where an area for disposal will already have been prepared. The waste will be covered immediately. Hazardous Waste Contingency Plan In the event that unacceptable waste is detected at the landfill, appropriate equipment, protective equipment, personnel, and materials as necessary will be employed to isolate the wastes. The NCDEQ Division of Solid Waste Management will be notified immediately that an attempt was made to dispose of waste that was generated outside the permitted Service Area. If the vehicle attempting disposal of such waste is known, all attempts shall be made to prevent that vehicle from leaving the site or, if the vehicle has left the site, immediate notice will be served on the owner of the vehicle that this unacceptable waste, for which they have responsibility, has been disposed of at the landfill. The landfill staff shall assist the Division of Solid Waste Management as necessary. If needed, the unacceptable waste will be covered with either on-site soils or other tarping material until such time when an appropriate method can be implemented to properly handle the waste. 3 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal Should an incident where hazardous waste is found at the landfill occur, the event shall be documented as follows: • Date and time of material detection. • Hauler name (company and driver). • Material(s) detected. • Material generator(s) if able to identify. • Action(s) taken to manage or return material(s). • Efforts taken if extreme toxicity or hazard was discovered. • Existing Landfill employee in responsible charge. Records of information gathered as part of the random waste inspection programs will be maintained at the landfill expansion during its active life and as long as required by regulation. Waste Disposal Placement of Initial Lift During solid waste placement operations, the landfill liner systems are most vulnerable during the placement of the first lift of solid waste. The first lift of MSW should be comprised of select loads spread on top of the operational cover above the leachate collection layer. These select loads must be free of long or large pieces of waste that may be pushed through the leachate collection layer and damage the liner. The first lift should be a minimum of 4 feet thick and provide sufficient area for at least one day’s operation without placing other areas of the liner in jeopardy. Another area of the liner system that is vulnerable during placement of the first lift of solid waste is the perimeter berms. The protective cover layer against the side wall will protect the liner system. As with the bottom liner, the first lift of MSW against the liner side walls should be comprised of select loads. In the event that the landfill supervisor identifies any damage to any part of the liner system, he should immediately affect its repair. Additionally, he should document the damage and the repair as a part of the operating record. General Procedures Solid waste transportation vehicles will arrive at the working face at random intervals. There may be a number of vehicles unloading waste at the same time, while other vehicles are waiting. In order to maintain control over the off-loading of waste, a certain number of vehicles will be allowed on the working face at a time. The actual number will be determined by the traffic spotter. This procedure will be used in order to minimize the potential of off-loading non- acceptable waste and to control disposal activity. Operations at the working face will be conducted in a manner which will encourage the efficient movement of transportation vehicles to and from the working face, and to expedite the unloading of solid waste. This will all be performed in a safe manner. 4 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Waste Disposal The approach to the working face will be maintained such that two or more vehicles may safely unload side by side. A vehicle turn-around area large enough to enable vehicles to arrive and turn around safely with reasonable speed will be provided adjacent to the unloading area. The vehicles will back to a vacant area near the working face to unload. Upon completion of the unloading operation, the transportation vehicles will immediately leave the working face area. Personnel will direct traffic as necessary to expedite safe movement of vehicles. Solid waste unloading at the active landfill will be controlled to prevent disposal in locations other than those specified by site management. Such control will also be used to confine the working face to a minimum width, yet allow safe and efficient operations. The width and length of the working face will be maintained in order to maintain the appearance of the site, control windblown waste, improve operational efficiency and, when necessary, minimize amount of cover soil required each day. Normally, two working faces will be active on any given day, with all deposited waste in other areas covered by either daily, intermediate, or final cover, as appropriate. The procedures for placement and compaction of solid waste include: unloading of trucks, spreading of waste, compaction on relatively flat slopes using a landfill compactor and a minimum number of passes. Uses of portable signs with directional arrows and portable traffic barricades will facilitate the unloading of wastes to the designated disposal locations. These signs and/or barricades may be placed along the access route to the working face of the landfill or other designated disposal areas which may be established. Equipment Operations within the Landfill Cell Both the facilities operational vehicles and solid waste transportation vehicles must be restricted as follows within the landfill cells. • Equipment operation directly on the operational cover above the leachate collection layer shall be limited to rubber-tired vehicles having a maximum ground contact, (i.e., low ground pressure, of less than 32 psi.) • A minimum vertical separation of 3 feet shall be maintained between the geomembrane liner and all solid waste transportation vehicles. • A minimum vertical separation of 5 feet shall be maintained between the geomembrane liner and trash compactors or tracked operational vehicles. The operation of vehicles within those portions of the cell not actively receiving waste should be restricted to activities associated with sedimentation and erosion control. Procedures for Stormwater Separation Each lined landfill cell is divided by berms into hydraulically isolated subcells designed to allow the operator to limit the amount of stormwater entering the leachate collection system. Prior to placement of refuse in a subcell, the subcell must be isolated from the stormwater drainage system and connected to the leachate collection system. Isolation of the subcell from the 5 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Alternative Daily Cover stormwater system is accomplished by removing the stormwater pipe leading into the next subcell. The subcell is then connected to the leachate collection system by physically removing the geosynthetic rain cover (GRC) over the entire subcell. A GRC will be installed on top of the operational cover located above the leachate collection layer to prevent stormwater from entering the leachate collection system. The GRC shall be installed according to manufacturer’s specifications. In general, the GRC can be ballasted by anchor trenches, tires, rope, sandbags, or windscreen. Stormwater runoff is controlled by building up a berm underneath the GRC to act as a diversion ditch. Typically, the GRC is removed by rolling the material in a direction so as to roll it up the slope. Stormwater that has collected in isolated subcells that have not received waste is not considered leachate and may be pumped into sediment ponds as normal stormwater. Alternative Daily Cover At the end of each working day either six inches of soil, or an NCDEQ approved Alternative Daily Cover (ADC) material, will be used to encapsulate exposed refuse. NCDEQ approved material is documented in the following: Approved Alternative Daily Cover Materials for Use at Sanitary Landfills, as amended Date of Issue: January 7, 2014 Document number 20365 Examples of approved ADC are: • Construction and Demolition Debris (C&D) Fines • Combustion Residuals (CR) Ash • Spray-Applied Coating (Posi-Shell®) • Synthetic Tarps • Petroleum Contaminated Soils (PCS) • Foam Coating • Foundry Sand • Automotive Shredder Residuals (ASR) • Soil/Mulch mixture The approved ADCs will be handled and applied by methods documented in the above mentioned document. As a contingency the City will maintain a soil stockpile on-site for use as daily cover, should circumstances warrant it. Any area not receiving waste for a period of 12 months will have a minimum of 1 foot of intermediate soil cover. 6 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Concrete, Asphalt, and Brick Operations Concrete, Asphalt, and Brick Operations Concrete, asphalt, and brick (CAB) is received, inspected, unloaded and stockpiled at the landfill within the areas shown on the Facility Plan. A trained inspector will visually inspect every load to assure that only loads of clean, uncontaminated CAB are unloaded and stored at the designated location. Any loads that are found to contain anything other than clean, uncontaminated CAB will not be allowed to unload and will be directed to unload at the working face of the MSW disposal area at the landfill and the hauler will pay the full tip fee for the load unless the hauler chooses to take the load to another landfill permitted to accept such waste. Materials other than CAB discovered after unloading will be properly disposed of at the landfill. Regardless of the amount of CAB received, the landfill will not accept and stockpile more than the capabilities of the storage areas identified. At approximately 50,000 tons of CAB, the landfill will immediately proceed to the final stage of the process, which includes turning the stockpiled CAB into stone for use at the facility. This will involve the retaining of a vendor to crush, chip or otherwise process the large pieces of CAB into useable aggregate. This processed material will then be stockpiled within the same area for periodic use onsite. Explosive Gases Control A gas monitoring system has been constructed around the perimeter of the Existing landfill by a third party. The existing system will be expanded to cover the proposed landfill expansion. This system will monitor for gas migration along the perimeter of the landfill expansion. All buildings and enclosed structures at the landfill will be monitored as part of a routine methane monitoring program. Methane Monitoring Well Placement In accordance with Rule 1626 (4)(b), the following factors were used to determine gas monitoring well placement: soil conditions, hydrologic conditions, hydraulic conditions, and location of facility structures. Monitoring well locations are shown on the Landfill Gas Monitoring Plan provided in the Landfill Gas Monitoring Plan. Methane Monitoring Program Routine monitoring for gas migration will be performed in accordance with Rule .1626 Part (4)(a) on a quarterly basis to ensure that the following compliance levels for methane concentration are not exceeded: 1) the concentration of methane gas generated by the facility does not exceed 25 percent of the lower explosive limit (LEL) for methane in facility structures (1.25 percent methane); and 2) the concentration of methane gas migrating from the landfill expansion does not exceed the LEL for methane at the facility property boundary (5 percent methane). The monitoring device that will be used will be a combustible gas indicator (CGI). If concentrations are measured at greater than 25 percent of the LEL for methane in facility structures, then the landfill must immediately take all necessary steps to ensure protection of human health and shall notify the Division of Solid Waste Management. Within seven days of detection, the methane gas levels detected and a description of the steps taken to protect 7 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Sedimentation and Erosion Control human health shall be placed in the operating record. Within 60 days of detection, a remediation plan describing the nature and extent of the problem and the proposed remedy for methane gas releases shall be placed in the operating record, the remediation plan shall be implemented, and the Division of Solid Waste Management shall be notified. Sampling and Analysis Procedures The City may have an independent contractor perform methane sampling and analysis in accordance with the Landfill Gas Monitoring Plan. Emergency Response Plan In the event methane gas levels exceed allowable limits within structures, the emergency response plan will be as follows. • For structures with greater than 25 percent LEL: o evacuate immediately, leaving doors open, o notify Winston-Salem Fire Department Hazardous Material Team, o notify NCDEQ, o notify consulting engineer, and o follow emergency procedure outlines in 15A NCAC 13B.1626(4)(c). • For structures with 0-25 percent LEL: o conduct follow-up monitoring, and o discuss with consulting engineer. Sedimentation and Erosion Control The landfill expansion area will be constructed with maximum waste sideslopes of 3H:1V and minimum 8% top slopes to promote runoff and prevent ponding over or in the waste. Side slope terraces and perimeter drainage channels at the toe of the slope will provide runoff, erosion, and sediment control. The drainage channel allows for the movement of surface water from landfilling activities and provides a settling zone for sediments carried from the site. The channel is constructed to allow drainage via sediment basins through natural outfalls and tributaries to Grassy Creek. Measures to control sedimentation and erosion will include the drainage channel, sediment basins, silt fences, slope drains, sediment traps, temporary and permanent seeding. Within 30 working days or 120 calendar days of completion of any phase of landfill development a vegetative ground cover sufficient to restrain erosion will be accomplished. All measures will be constructed or installed in accordance with standards specified in the North Carolina Erosion and Sediment Control Planning and Design Manual. Sediment basins will also prevent the discharge of pollutants that violate requirements of the Clean Water Act, including, but not limited to, NPDES requirements, into the waters and wetlands of the United States. 8 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management The landfill expansion area will have a comprehensive surface and groundwater monitoring program to provide early detection of any leachate migration problems. In the event any constituents are detected above allowable limits, measures will be taken to begin assessing the extent of contamination and, if necessary, corrective actions will be taken to prevent the pollution of waters and wetlands of the United States, that violate any requirements of an area- wide or state-wide water quality management plan that has been approved under Section 208 or 319 of the Clean Water Act, as amended. Leachate Management General Collection and removal of leachate generated from waste within expansion landfill will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, they will be cleared of debris using the cleanout riser pipes for access. The maintenance and cleaning will be performed on a as necessary basis to maintain the free flow of leachate in accordance with NC General Statutes 130A-295.6(h)(3). The pipes will be cleaned with jetted water and all cleanings will be recorded on the Leachate Pipe Cleaning Form. If pipes are damaged, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Remote camera inspections of the leachate lines will occur upon completion of construction, at least once every five years, and following the clearing of all blockages in accordance with NC General Statutes 130A-295.6(h)(3). Records of the inspections will be recorded on the Remote Camera Video Inspection Form. The Phase 2 collection system includes collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C, respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the existing landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. 9 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Cleaning Report in the file. Leachate Pipe Cleaning Form* Pipe ID Date Cleaning Company Persons Operating the Equipment Comments about Cleaning 10 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management * Please include a copy of the Inspection Report in the file. Remote Camera Video Inspection Form* Pipe ID Date Inspection Company Persons Operating the Equipment Comments about Inspection 11 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Leachate Management According to the letter dated September 13, 2005 from the City/County Utilities Department, the landfill is not required to have a permit to discharge leachate at the wastewater treatment plant. Leachate Pretreatment and Discharge At this time, leachate pretreatment is anticipated to consist of only equalization in the storage tanks. Existing on-site leachate quality tests do not indicate a need for pretreatment at this time. Testing of leachate quality will continue during the life of the Hanes Landfill facility. Dependent on the outcome of future tests, an appropriate system, if required, will be designed. Separation of Stormwater Storm water control measures will be employed within lined subcells which have not received waste. These measures include “sectioning off” unused subcells or portions of subcells by employing GRC and temporary subcell divider berms. In addition, a sump will be created at the low end of the subcell to facilitate stormwater removal. In general, temporary sumps are formed where the subcell divider berms intersect the perimeter berm. Stormwater drains toward the temporary sumps on top of the GRC. The formation of temporary sumps permits stormwater to be pumped as required. In this way, the landfill expansion operator retains a degree of flexibility throughout the life of the landfill expansion. As filling operations are initially proceeding, stormwater from unfilled subcells is kept out of the leachate collection system. The temporary sumps also enable the operator the potential to monitor both the quantity and quality of leachate and enable separation or isolation of specific areas in the event of a problem. Prior to the commencement of filling activities in the subcells, the temporary discharge pipes will be removed to prevent discharge of leachate into an inactive subcell. Leachate Quality Sampling Semi-annual sampling will be performed in accordance with .1626(12)(c). Samples will be recovered as grab samples from the leachate storage tank. The parameters to be analyzed will include BOD, COD, temperature, conductivity, phosphate, pH, ammonia, suspended solids, sulfates, nitrates, and metals analysis. Analyses will also include a volatiles scan. Please refer to the Water Quality Monitoring Plan for more detail. CFR 258 Appendix I outlines the list of metals and volatiles to be tested. Leachate Contingency Plan In the event that leachate levels within the first tank reach the freeboard capacity, a high crossover pipe will allow flow into the second tank. In the event that both tanks reach the freeboard capacity due to unforeseen events, the excess leachate will either be piped directly to the sewer and then to the POTW or stored temporarily in the landfill expansion. Engineering structures (secondary containment) have been constructed to prevent leachate from entering local waterways. If operational conditions allow, leachate recirculation may be performed with prior NCDEQ approval. 12 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Air Quality Control Air Quality Control Mandates of the US Environmental Protection Agency (EPA) Clean Air Act and corresponding Forsyth County regulations will be met as they become effective. The primary control mechanism will be the proposed active gas extraction system. All equipment at the facility will have fire extinguishers on board. The extinguishers will be properly classified and inspected. All operators will be trained for proper use of extinguishers. Open burning of solid waste is prohibited at the site. The fire department will be notified in cases of emergency, such as a landfill fire. NCDEQ will be notified by a phone call within 24 hours of a landfill fire. A follow-up report detailing the nature of the fire and any respective action taken will be mailed to NCDEQ within 15 days of the landfill fire. Access and Safety Requirements The facility is almost totally enclosed by a 6-foot chain link fence with triple strands of barbed wire to prevent unauthorized entry into the site. Areas currently not protected by fencing are inaccessible by motor vehicle due to steep water barriers, railroads etc. The access road to the working face will be of all-weather construction and kept in good condition. Dust control and tracked mud will be controlled on the access roads as needed. Proper signage directing and informing facility users will be placed in high visibility areas, including signs stating that no hazardous or liquid wastes can be received. Removal of MSW from the facility will not be allowed without the approval of the facility supervisor. Under no conditions will the removal of MSW from the working face be allowed. No barrels or drums will be disposed of at the facility without sufficient perforations to ensure that no liquid or hazardous wastes are contained in them. The facility will be staffed during all operating hours to ensure operational compliance. Spreading and Compacting Program Incoming waste at the facility will be confined to the most efficient working face feasible. Solid waste will be compacted as densely as practical into cells. Appropriate control devices such as berms, fences, and cover material will be used as needed to prevent windblown debris. Any windblown debris will be collected by on-site staff or temporary laborers. The landfill also has a litter control program. For example, the landfill has installed litter control fences that help capture blowing litter. In addition to these fences, labor is also used to manually remove the blown litter that lies outside the environs of the working face. In the event of extremely windy days, temporary labor and/or prison/community service labor will be used to remove the blown litter. This windblown litter will be bagged and returned to the working face. 13 City/County Utility Commission | Hanes Mill Road Landfill – Operations Plan Record Keeping Program Record Keeping Program Records for tonnage and waste generators will be kept at the office of the City’s Solid Waste Administrator and made available to NCDEQ upon request within a reasonable period of time. Records for facility inspections, gas/groundwater monitoring results and corresponding analytical data, closure/post-closure cost estimates, financial assurance documentation and employee training will be kept at the facility. The information will be made available to NCDEQ upon request within a reasonable period of time. Copies of the operation plan will be kept at the facility. 14 Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents Contents Cap System Background ........................................................................................................... 1 Cap System Design ................................................................................................................... 1 Final Contour Requirements ...................................................................................................... 2 Cap System Material Requirements ........................................................................................... 2 Surface Water Control Measures ............................................................................................... 2 Permanent Erosion Control Measures ....................................................................................... 3 Settlement Subsidence and Displacement ................................................................................. 3 Leachate Control ........................................................................................................................ 3 Gas Collection/Venting System .................................................................................................. 3 Schedule for Closure.................................................................................................................. 3 Notice of Closure and Date of Final Waste Acceptance ............................................................. 4 Implementation of Closure Plan ................................................................................................. 4 Closure Verification .................................................................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Cap System Background Cap System Background In compliance with the NCDEQ Solid Waste Management Rules, the landfill expansion will place a final cap system over all waste placed in the proposed expansion. The layers of the cap system will be designed and constructed in accordance with Rule .1627 (c)(3), to minimize infiltration and erosion. It is estimated that the total landfill volume at completion will be 12,200,000 cubic yards for the 90+/- acres foot print. The maximum area requiring a cap at any one time shall be 65 acres. Cap System Design The desired cap system design may change as new technologies develop. The cap system designed will be checked prior to closure, revised and permitted as appropriate. Compacted soil liners will be incorporated in the cap system design to provide protection throughout the 30-year post-closure period and beyond. The regulatory prescriptive system consists of four layers (bottom up); the compacted soil liner; a geomembrane; a drainage layer (possibly a geonet layer or more appropriate layer); and the erosion layer. The geomembrane and compacted soil liner form a composite barrier designed to reduce infiltration into the landfill expansion, thus minimizing leachate and the potential for groundwater contamination. The erosion layer is designed to protect the composite barrier. The expansion landfill may use on-site or off-site borrow material for the compacted soil layer. The compacted soil layer will consist of no less than 18 inches of soil having permeability equal to or less than 1 x 10-5 cm/sec. In order to assure that the material meets the permeability criteria, the soil will be tested prior to use and after placement. Testing requirements will be outlined in the final closure plan. It is anticipated that the upper 6 inches of the intermediate cover will be suitable for compaction and incorporation into the compacted soil layer. Construction methods for the compacted soil liner shall be based upon the type and quality of the borrow source and shall be verified in the field by constructing test pad(s). A professional engineer shall certify that the compacted soil liner installation conforms with the plans approved by the NCDEQ Division of Solid Waste Management. While NCDEQ rules require that the erosion layer shall consist of no less than 6 inches of earthen material capable of sustaining native plant growth, it is anticipated that the erosion layer for closure of the expansion landfill will consist of 12 inches of suitable on-site borrow material. That 12-inch layer will then be covered with a 6-inch topsoil layer. The materials of the erosion layer will be selected considering: soil type, nutrient levels, pH, erodibility, sideslope drainage, and other factors. The vegetation (typically Kentucky Fescue) should be selected based on the following criteria. • Species of grasses which are locally adapted and resistant to drought or temperature extremes. • Having roots which will not disrupt the low permeability layer. • Ability to thrive in low nutrient soil and develop a good stand to resist erosion. 1 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Final Contour Requirements • Able to survive and function with little or no maintenance. All cover material will be free of putrescible material, solid waste, vegetation, rocks, construction debris, frozen soil, and other deleterious materials. Seismic and general slope stability analyses have been performed and can be found in the Phase 2 Application to Construct. Final Contour Requirements The final contour requirements for closure are shown on the drawings included with the Phase 2 Application to Construct. These contours have been established to reflect all municipal solid waste expected to be received, intermediate cover material (representing an initial total of 12 inches and a final total of 6 inches), and the final cover system (representing a total of 3 feet). Cap System Material Requirements Based on the cap design submitted in this amendment, 18 inches of compacted soil placed over the Phase 1 and 2 areas at final closure, 157,000 cubic yards of compacted soil will be required for the first layer of the cap system. A minimum of 105,000 cubic yards will be required for the erosion layer soil. An estimated 52,500 cubic yards of earthen material will be required for the 6 inches of top soil layer. An estimated 2,831,400 square feet of geomembrane will be used in drainage ways and on the top slopes of the completed landfill. The following table summarizes the cap system requirements for Phases 1 and 2 of the landfill expansion area. Table Cap System Requirements - Phases 1 & 2 Material Quantity 18-inch Compacted soil liner 157,000 CY 12-inch Erosion layer soil 105,000 CY 6-inch Top soil layer 52,500 CY Geomembrane 2,831,400 SF Surface Water Control Measures The landfill expansion area is designed to have top slopes of 8 percent and side slopes of 3H:1V. Final contours have been established to allow the landfill expansion surface water to drain off the final cover while limiting erosion potential and maintaining post settlement slopes greater than 5 percent. Surface water runoff from the top slopes is intercepted by a diversion berm that separates the top slopes from the side slopes and carried off of the cover via down pipes. The side slopes incorporate a system of drainage terraces to limit surface water flow length. The vertical spacing of the side slope terraces is approximately 40 feet. The side slope terraces will drain into the down pipes which, in turn, drain to the perimeter drainage channel. The surface waters will be conveyed by the perimeter drainage channel to one of four sedimentation basins located adjacent to the landfill expansion. The maximum length of sheet flow (~300 ft) will occur on the 8 percent slopes. Drainage terraces will direct flow across the 3H:1V percent slopes into the down pipes and into the sediment basins. 2 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Permanent Erosion Control Measures Permanent Erosion Control Measures The expansion landfill is situated near an intermittent stream at the southern end of the site and adjacent to Grassy Creek. A system of drainage channels and sedimentation basins will be used to protect the intermittent stream and Grassy Creek from sediment laden runoff. The sedimentation basins were designed to control the 25-year storm event and achieve a minimum of 70 percent efficiency in settling a sediment particle with a diameter of 40 microns. The sedimentation basin design calculations may be found in the Application to Construct calculation section. Settlement Subsidence and Displacement Landfill compaction methods which include the use of steel-wheeled compaction equipment to spread and compact in layers, combined with an adequate number of passes over each layer of waste, will be utilized to reduce voids and minimize differential settlement. Proper placement of daily, intermediate, and final cover will reduce the moisture content of the waste prior to site closure and further reduce settlement. Final slopes of the landfill expansion have been developed to allow for this anticipated subsidence so that long-term positive drainage of the fill will not be hindered. Leachate Control The installation of the final cap system over the fill area will greatly reduce infiltration of surface water and lessen the potential for leachate generation. The landfill expansion area has a comprehensive surface and groundwater monitoring program to detect any potential leachate migration problems. This program, which is discussed in Water Quality Monitoring Plan, will be continued throughout the post-closure care period. Gas Collection/Venting System An active gas venting system will be installed under the cap to allow movement of gas generated from the completed fill area to the existing gas collection system. The gas collection system will be an extension of the one used at the existing landfill. The collection system is presently maintained by an independent contractor. Schedule for Closure The design of the landfill expansion in combination with the maintenance plan should assure a fairly uncomplicated closure period. The closure of the entire unit, or portions thereof, will be completed within 180 days unless an extension has been requested and received due to changes in the anticipated schedule. 3 City/County Utility Commission | Hanes Mill Road Landfill – Closure Plan Notice of Closure and Date of Final Waste Acceptance Notice of Closure and Date of Final Waste Acceptance A sign indicating the anticipated date of closure and the date of final waste acceptance will be conspicuously posted at the facility at least 30 days in advance. The landfill may take other steps to notify the public of the planned closure. Prior to beginning closure of the unit or portions thereof, the NCDEQ Department of Solid Waste Management will be notified that a notice of intent to close has been placed in the operating record. Implementation of Closure Plan The closure plan will be implemented as soon as possible from the date of final waste acceptance and completed in accordance with state regulations. Closure Verification The following procedures will be implemented following closure. • A Construction Quality Assurance (CQA) report shall be submitted to the NCDEQ Division of Solid Waste Management. This report shall describe the observations and tests used before, during, and upon completion of construction to ensure that the construction materials meet the cap design specifications and the construction and certification requirements. The CQA report shall contain as-built drawings. • A signed certification from an independent registered professional engineer verifying that closure has been completed in accordance with the closure plan will be submitted to the NCDEQ Division of Solid Waste Management. • At least one sign notifying all persons of the closing of the phase and that wastes are no longer accepted will be posted. Suitable barriers will be installed as necessary at former accesses to prevent new waste from being deposited. • Within 90 days, a survey plat, prepared by a professional land surveyor registered by the State, indicating the location and dimensions of landfill disposal areas, will be submitted to the Forsyth County Register of Deeds. • A notation shall be recorded on the deed notifying any potential purchaser of the property that the land has been used as a solid waste management unit and that future use is restricted under Paragraph (8) of Rule .1627. A copy of the deed notation as recorded shall be filed with the operating record. 4 Post Closure Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents Contents Introduction ................................................................................................................................ 1 Post-Closure Contact ................................................................................................................. 1 Description of Use ...................................................................................................................... 1 Maintenance .............................................................................................................................. 1 Repair of Security Control Devices ......................................................................................... 1 Erosion Damage Repair ......................................................................................................... 2 Correction of Settlement, Subsidence and Displacement ....................................................... 2 Leachate Collection System ................................................................................................... 2 Closure of Storage Tanks ....................................................................................................... 3 Repair of Run-On/Run-Off Control Structures ......................................................................... 3 Gas Collection/Venting System .............................................................................................. 3 Groundwater Monitoring System ............................................................................................ 3 Monitoring Plan .......................................................................................................................... 4 Inspection Frequencies .......................................................................................................... 4 Quarterly Inspections .............................................................................................................. 4 Semi-Annual Inspections ........................................................................................................ 4 Engineering Certification ............................................................................................................ 5 Tables Table 1 Post-Closure Inspection Frequencies ........................................................................... 4 i City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Introduction Introduction This Post-Closure Plan has been developed to outline steps to be taken to ensure the environmental soundness of the landfill expansion during its post-closure care period. The post- closure period begins when the Closure Verification Report is submitted to NCDEQ. The post- closure care period will be in accordance with the latest NC regulations, 15A NCAC 13B .1627 (d). and will consist of the following. • Maintaining integrity and effectiveness of final cover system. • Performing groundwater and surface water monitoring. • Maintaining and operating a gas monitoring system. • Maintaining run-on/run-off controls. No wastes will remain exposed after closure of the unit. Access to the closed site by the public or domestic livestock will not pose a health hazard. Post-Closure Contact All correspondence and questions concerning the post-closure care of the unit should be directed to: Solid Waste Administrator City of Winston-Salem Hanes Mill Road Landfill 325 West Hanes Mill Road Winston-Salem, NC 27105 336-747-7310 Description of Use After filling operations cease at the landfill expansion area and the unit is officially closed in accordance with the Closure Plan, the area will be allowed to return to a natural vegetative state. The City will maintain control of the property. The City may develop the land for recreational uses such as greenways, parks, etc. There will be an access road on the cap to allow proper maintenance during post-closure. Final location of the access will be determined as a part of operations. Maintenance Repair of Security Control Devices All security control devices will be inspected and maintained as necessary to ensure access to the site is controlled. Locks, vehicular gates, and fencing will be replaced if functioning improperly. Warning signs will be kept legible at all times and will be replaced if damaged by inclement weather or vandalism. 1 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance Erosion Damage Repair If erosion of the final cover occurs during post-closure, the affected area will be repaired and re- seeded as necessary. Excessive slopes will be flattened if possible by adding clean fill material. If necessary, erosion control fabrics will be used to expedite rapid re-vegetation of slopes and to secure topsoil in place. Rough surfaces which cause isolated erosion areas will be smooth and re-seeded as necessary. Correction of Settlement, Subsidence and Displacement Slopes will be maintained in order to prevent ponding and allow for proper drainage without infiltration. If vertical or horizontal displacement occurs due to differential settlement, cracks will be filled with appropriate material and final cover will be reestablished. Excessive vertical displacement is not anticipated. Leachate Collection System Collection and removal of leachate generated from waste will be accomplished by a system of perforated HDPE pipes installed within stone-filled trenches. Leachate will be collected by gravity within the unit and pumped to the on-site storage tanks before it is pumped via force main to the wastewater treatment facility. In order to maintain the free flow of leachate collection pipes, the pipes will be cleared of debris using the cleanout riser pipes for access. All leachate collection lines shall be designed and constructed to permanently allow cleaning and remote camera inspection. All leachate collection lines shall be cleaned as found necessary for proper function and to address buildup of leachate over the liner. Remote camera inspections of the leachate collection lines shall occur at least once every 5 years during the post closure period and following the clearing of blockages. If leachate pipes fracture, leachate will flow through the stone trench backfill material. A continuous granular blanket will allow drainage of leachate even in the event of total failure of the leachate collection lines. Although total failure of the leachate collection system is unlikely, it may be possible to remove leachate from sumps constructed at the natural drainage points inside the lined area. The Phase 2 system includes leachate collection pipes underneath the expansion area that drain to gravity headers. These headers in turn flow by gravity to the Sumps 1 and 2 located in Phase 1, Cells 1A and 1C respectively. Leachate in the sump areas will be pumped up sideriser pipes to the above-ground storage tanks. The leachate will then be gravity drained to an existing gravity sewer main located to the west of the closed landfill. The sewer main ultimately discharges into the City/County-owned wastewater treatment facility for final treatment. The sideriser pumps will be maintained in good working order throughout post-closure. Since leachate volume will be decreased during post-closure, the maintenance schedule will be adjusted in accordance with manufacturer’s recommendations. As during landfill operations, a high-level alarm system will be in place to warn of pump failure or other system breakdowns. Further, due to the design of the system, the high-level alarm will serve as a monitoring system for prevention of greater than 1 foot of leachate head on the liner system. 2 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Maintenance Closure of Storage Tanks After closure of the landfill expansion area has been achieved, the generation of leachate will eventually curtail. The flow rate immediately after closure should decrease to less than 100 gallons/acre/day (gpapd). Toward the end of the 30-year post-closure period, the flow should approach zero, at which time the storage tanks will not be required. The following procedures will be followed to properly close the storage tanks. • Completely drain and remove all liquids, sludges, sediments, etc. from the storage tanks. • Disassemble the tank, piping, and appurtenances and dispose of the contents in a manner approved by NCDEQ. • Sample and analyze the soil for appropriate constituents inherent to leachate. Assess the results for evidence of contaminant migration. • If contamination of underlying soils is exhibited, perform an assessment as to the degree of contamination and develop remedial actions. • Obtain approval of NCDEQ for the assessment and associated remedial measures. • Perform the remedial actions as necessary to limit any threats to public health and the environment. • Install permanent vegetation in the vicinity of the containment area. Activities may include filling, grading, topsoiling, and seeding. Repair of Run-On/Run-Off Control Structures All side slope terraces, ditches, and perimeter channels will be repaired, cleaned, or realigned in order to maintain original condition. Any culverts that are damaged will be replaced. Gas Collection/Venting System The landfill gas collection and venting system will be maintained. Currently, a third party manages and operates the existing gas system. Proper operation of the systems is verified through testing at the landfill gas monitoring wells and probes. If methane gas recovery wells do not function as a result of irregular settlement, accumulation of liquids (condensate, leachate, and water), binding or corrosion, replacement wells can be installed if necessary. Non-functioning vents will be reset if necessary. Groundwater Monitoring System All groundwater monitoring wells have been installed with concrete pads and protective casings to prevent accidental damage by vehicles and equipment. The wells are also equipped with a locking cap to discourage vandalism. Groundwater wells will be inspected regularly (at the time of sampling) to ensure integrity. Persons inspecting a well should look for signs of well tampering, cracking or degradation, and determine whether the well needs to be replaced. If the decision is made to replace and abandon a well, the replacement well should be installed 5 to 10 feet from the abandoned well in accordance with previous well specifications. Well abandonment should be accomplished by pulling the casing out and grouting the hole. Refer to the approved Water Quality Monitoring Plan for detailed information on the groundwater monitoring system 3 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Monitoring Plan Monitoring Plan The closed unit shall be monitored in accordance with 15A NCAC 13B .1627 (d). A series of inspections shall be scheduled to ensure the integrity and effectiveness of the cap system, storm water control system, groundwater monitoring system, gas collection system, and to protect human health and the environment. Inspection Frequencies Inspections to be conducted during the post-closure care period will occur regularly as shown in Table 1 below. A copy of the Post-Closure Inspection Checklist is included at the end of this document. Table 1 Post-Closure Inspection Frequencies Inspection Activity Years 1-3 Years 4-30 Security Control Devices Quarterly Quarterly Cover Drainage System Functioning Quarterly* Semi-annually Leachate Collection System Quarterly Semi-annually Gas Collection/Venting System Quarterly Semi-annually Groundwater Monitoring System Semi-annually Semi-annually Erosion Damage Quarterly* Quarterly Cover Settlement, Subsidence, and Displacement Quarterly Semi-annually Vegetative Cover Condition Quarterly* Quarterly Stormwater Control System Quarterly* Quarterly Benchmark Integrity Annually Annually Leachate Collection Pipe Flushing Annually Annually * These items will also be inspected in accordance with the current NPDES Permit. Quarterly Inspections Quarterly inspections of the closed site will include examination of the security control devices for signs of deterioration or vandalism to ensure access to the site is limited to authorized persons. The previous disposal area will be checked to ensure the integrity of the final cover system is maintained, erosion damage is repaired, vegetative cover persists, and that cover settlement, subsidence and displacement are minimal. Drainage ditches will be cleared of litter and debris and benchmark integrity will be noted and maintained. Semi-Annual Inspections Semi-annual inspections of the site during the post-closure period will be conducted by the City’s engineer with attention paid to integrity and drainage of the final cover system and proper functioning of the groundwater and gas monitoring systems. Groundwater monitoring will continue on a regular basis throughout the post-closure care period. The parameters chosen for analysis will be no less than the requirements of regulatory agencies. Groundwater monitoring wells will be inspected in accordance with the post-closure 4 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification inspection protocol. A report of findings will be made to the responsible party via the Post- Closure Inspection Checklist, including any recommendations for actions necessary to ensure the site continues to meet the closure performance standard. The engineer will also receive copies of the quarterly inspections reports and respond to any comments that demand immediate attention. Engineering Certification Based on the City’s monitoring reports and an engineer’s semi-annual site visits, annual certifications by the engineer will be placed in the operating record. They will certify that the closure plan has been followed, noting discrepancies along with the corrective actions undertaken. At the end of the post closure period, a certification will be forwarded to NCDEQ Division of Solid Waste Management. 5 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification Post-Closure Inspection Checklist Location: Date: Time: Weather: Completed By: Yes No I. Security Control Devices: Are security control devices in place and functioning?   Are all warning signs prominent and legible?   Are there any signs of unauthorized entry on the site?   Are there signs of illegal dumping on site?   II. Final Cover System: Is the final cover free of erosion and depressions?   Is there leachate seeping from the final cover? (If yes, make note of location on comment section below.)   Is the vegetative cover continuous and in good condition, free of bare spots?   Does the site require mowing? (If yes, mow grass and note in comment section below.)   Is there ponding of water on final cover system?   III. Groundwater Monitoring Wells: Is the casing upright and unobstructed?   Is the outer casing secure and locked?   Is the ID tag present and legible?   IV. Miscellaneous: Are all benchmarks visible and intact?   Are all ditches free of debris and litter?   Are any odors present which may indicate landfill gas migration?   6 City/County Utility Commission | Hanes Mill Road Landfill – Post Closure Plan Engineering Certification COMMENTS Please use the section below to comment on any area not covered above and also to note any areas of concern or needing immediate attention. 7 This page intentionally left blank. Water Quality Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents Contents Purpose and Intent ..................................................................................................................... 1 Background ................................................................................................................................ 1 Hydrogeologic Setting ............................................................................................................ 2 Water Quality Monitoring Program for Unit 1 .......................................................................... 5 Proposed Water Quality Monitoring Plan.................................................................................... 5 Sampling Locations ................................................................................................................ 6 Data Collection ....................................................................................................................... 7 Well Construction ..................................................................................................................10 Analytical Procedures ............................................................................................................10 Tables Table 1 Summary of Monitoring Sample Locations and Functions ............................................ 9 Table 2 Monitoring Network Well Construction Details .............................................................10 Table 3 Updated MNA Monitoring Parameters and Methods ....................................................11 i City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Contents This page intentionally left blank. ii City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Purpose and Intent Purpose and Intent The purpose of this Revised Water Quality Monitoring Plan (Plan) is to provide a program for the collection and evaluation of groundwater, surface water and leachate samples at Unit 1 of the Hanes Mill Road Municipal Solid Waste Landfill (Landfill). The Plan describes the monitoring program for both the Subtitle D area and the unlined landfill area of Unit 1. This program evaluates samples from groundwater wells installed in the uppermost aquifer, as well as surface water, and leachate from the leachate collection system. Implementation of this plan will provide efficient and effective early detection of any release of hazardous constituents to the uppermost aquifer, so as to be protective of public health and the environment as well as evaluate the efficacy of ongoing corrective actions. As the waste mass continues to stabilize and remediation progresses, it is anticipated that the monitoring program will need to be periodically adjusted. As the groundwater remediation model continues to be validated over time, fewer confirmatory groundwater samples will be required. This Plan was prepared in accordance with North Carolina Solid Waste Management Rules 15A NCAC 13B, Sections .1630 through .1637 under the guidance of a North Carolina licensed geologist. Background The Landfill is located at the intersection of US Highway 52, Hanes Mill Road, and Ziglar Road and is owned and operated by the Winston-Salem/Forsyth County Utility Commission (Commission) under North Carolina Permit No. 34-02. Unit 1 of the Landfill is composed of an unlined portion (now closed) and a Subtitle D lined portion (aka the “piggyback”). Unit 1 ceased receiving waste in August 2005 and the Commission is now disposing of waste in the Expansion Landfill. The Expansion Landfill is not addressed in this section. The Commission conducted routine detection groundwater monitoring (Appendix I constituent list, per Rule 15A NCAC 13B .1633) for the unlined landfill until 1995. In 1995 and 1996, an assessment groundwater monitoring program (Rule 15A NCAC 13B.1634) was initiated due to exceedances of the North Carolina Groundwater Quality Standards (15A NCAC 2L, .0202). This assessment demonstrated that all impacts were limited in extent and confined to the facility’s property. The exceedances occurred in two monitoring wells located approximately 50 feet from the edge of the waste and resulted mainly from two sources of Volatile Organic Compounds (VOCs): primarily chlorinated solvents and their breakdown products and secondarily, benzene, toluene, and ethylbenzene – constituents found in petroleum products. An Assessment of Corrective Measures (ACM) was conducted and, based on the results, monitored natural attenuation (MNA) was selected as the most appropriate and cost-effective of the remedial options for the cleanup of the dissolved VOCs at the Landfill. This ACM was approved by the North Carolina Department of Environment and Natural Resources (NCDENR) in a letter dated March 24, 2005 (Gamble to McHargue). MNA involves collecting and evaluating data to document that the processes of natural attenuation are continuing to occur and are effective in meeting the remedial objectives. The Corrective Action Plan (CAP) to conduct MNA 1 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background at the Landfill was prepared and approved by NCDENR. Baseline MNA monitoring was completed and an assessment was detailed in the spring 2008 Semiannual Report. In response, NCDENR approved the request to remove four OW wells from the MNA monitoring on September 22, 2008 (including OW-6, OW-7DA, OW-11, and OW-13D). In accordance with the request from NCDENR, the addendum to the CAP was submitted to include additional corrective action measures and to revise the MNA monitoring plan. In the addendum, one background well (MW-1RR) and six down gradient wells (OW-3, OW-4, OW-10D, OW-12, OW- 14, and OW-17D) are included in the continuing MNA monitoring program which includes testing of Appendix II parameters. In a letter dated March 4, 2010 (Drummond to McHargue), NCDENR approved a request for a modification to reduce Appendix II groundwater monitoring to every other spring monitoring event at the closed unlined landfill beginning in 2011. As requested by NCDENR four independent samples were collected at the wells monitoring the closed unlined landfill (including the subtitle D cell) for detected Appendix II parameters to establish background groundwater concentration. Hydrogeologic Setting The Landfill is located in the southern Piedmont physiographic province of North Carolina. The physiography of the Piedmont is characterized by gentle to rough sloping terrain that becomes increasingly sloped closer to the mountains and is dissected by a well-developed drainage system. The topography is developed on deeply weathered, belted metamorphic and igneous rocks that generally date from late Precambrian to Paleozoic Era. According to the soil survey of Forsyth County, North Carolina, prepared by the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) (1976), the surficial soils at the Landfill belong to the Pacolet-Cecil association. These soils are characteristic of Piedmont uplands where well-drained soils with a loamy surface layer and a clayey subsoil layer are found predominantly on gently sloping to sloping land. The Landfill is dominated by three main soil series as shown on Sheets 9, 10, 15, and 16 of the survey. These include the Hiwassee series, the Pacolet series, and the Madison series. A fourth series (Chewacla series), found outside of the footprint of the proposed landfill unit(s), is present along the floodplain of Grassy Creek. According to the geologic map of the east half of the Winston-Salem Quadrangle, North Carolina-Virginia, compiled by Espenshade and others, 1975; the geologic units identified at or adjacent to the Landfill include the following: pCag-Ashe Formation, pCaa-Ashe Formation, bc- Charlotte Belt rocks, and qgc-Charlotte Belt rocks. Nearly all of the Landfill property is underlain by typical Ashe Formation lithologies. Field checks of the local geology confirm this conclusion. The lithologic protoliths include turbidite facies (the bulk of the formation) and basalt flows (the amphibolite facies). The Ashe Formation is estimated to be 12 to 15 kilometers in thickness (Rankin, D.W., 1970). The main surface water drainage features of the Landfill are the two tributaries of Grassy Creek to the north and south of the property, and Grassy Creek itself to the west. Surface water drainage from the area of the existing Landfill is controlled through a series of catch basins and sediment ponds. Some surface water drains from the Landfill area into both the north and south 2 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background streams, which then carry it to Grassy Creek via culverts beneath the Norfolk Southern railway at the west edge of the Landfill. Other surface water flows directly from the Landfill area to Grassy Creek via two culverts located between the north and south streams. The 100-year floodplain of Grassy Creek is located between 150 and 300 feet west of the Landfill at a topographic elevation between 800 and 805 feet msl. Since both of the bounding streams are perennial, they are also areas of groundwater discharge at the Landfill. Groundwater flow for this portion of the Landfill property is primarily west towards Grassy Creek, with minor components of groundwater flow towards two bounding streams named North Branch Creek (NBC) and South Branch Creek (SBC). Groundwater in the Piedmont occurs both intergranularly in the weathered saprolite and within fractures in the bedrock. Typically, the water table is within the saprolite, and water supply wells are completed in bedrock. Total porosity in saprolite is generally relatively high with measured values as high as 40 to 50 percent. In bedrock, porosity is normally only 3 to 5 percent, but fractures are often well connected and hydraulic conductivity is comparable to or higher than that found in the saprolite. As the saprolite and bedrock are hydraulically connected, the contrast between porosities allows the saprolite to act as a groundwater reservoir for wells that pump from the bedrock. Sustained well yields for well-constructed bedrock wells in the Piedmont average from approximately 15 to 30 gallons per minute (Charles C. Daniel, III and R.A. Payne, 1990). The water table in the Piedmont, under natural conditions, is a subdued image of the surface topography. Recharge takes place on interfluvial areas, then travels downward and laterally to discharge along creeks and rivers. Thus, the vertical component of groundwater flow is directed downward in interfluvial recharge areas, comprising approximately 80 to 90 percent of land surface, and then has an upward component of flow as groundwater moves to discharge areas at streams. The groundwater at the Landfill flows from the highland recharge area northeast of the Landfill toward Grassy Creek located west of the Landfill. Minor components of groundwater flow may also occur radially from the crest of the Landfill toward the drainage features to the north and south. Based upon several slug tests performed on selected wells and piezometers in the study area, the hydraulic conductivity of the uppermost limits of the saprolite aquifer is 1.61 feet per day (ft/day), while the hydraulic conductivity of the partially weathered rock (PWR) unit of the aquifer ranges from 0.78 to 5.77 ft/day. The upper limits of the fractured bedrock range in hydraulic conductivity from 1.40 to 3.77 ft/day. A groundwater flow velocity was calculated for each well location using a variation of Darcy’s Law. Employing the average hydraulic conductivity values for the saprolite/PWR and bedrock units, an estimated groundwater flow velocity was calculated for the well locations along the eastern side of Grassy Creek and the southern side of SBC. Assuming an effective porosity of 20 percent (0.20) for saprolite and PWR wells and 5 percent (0.05) for rock wells, with calculated hydraulic gradients associated with the vicinity of each of these monitoring wells, a groundwater flow (pore water seepage) velocity was calculated for the study area. 3 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Background The calculated seepage velocity for the saprolitic portion (including the PWR unit) of the uppermost aquifer in the vicinity of the assessment wells along the eastern side of Grassy Creek ranges from 0.014 to 0.305 ft/day, while the estimated groundwater flow rate of the upper limits of the fractured bedrock portion of the aquifer averaged slightly higher at 0.829 ft/day. Site Hydrogeologic History The following is a brief history of the sites monitoring wells and hydrogeologic findings from them. Vertical gradients between the saprolitic portion of the aquifer and the upper limits of fractured bedrock exhibit a downward component of flow, specifically at OW-7/7M, OW-7/7D, OW- 11/11M, and OW-12/12M. This downward gradient averages 0.004 feet per foot (ft/ft). On the other hand, there are strong upward vertical gradients measured in most of the deeper groundwater assessment wells completed within fractured bedrock. At the southern end of the plume, a downward gradient (at 0.001 ft/ft) is indicated between OW-7, completed within the saprolite, and OW-7D, completed within the upper limits of fractured bedrock. However, a strong upward gradient is present within the fractured bedrock. This can be seen by the gradients between the saprolite (OW-7) and the fractured bedrock at OW-7DA. An upward gradient of 0.004 ft/ft is measured from a depth between 111 and 114 feet bls, between OW-7 and OW- 7DA. Likewise, a strong upward gradient was also measured between 47 and 114 feet bls at OW-7D and OW-7DA at 0.007 ft/ft. At the center of the area of groundwater impacts, a strong upward gradient exists between the saprolite (OW-9) and the upper limits of fractured bedrock (at 65 feet bls) in OW-9D. Here, a gradient of 0.010 ft/ft was measured. This upward gradient becomes stronger with depth, increasing to 0.032 ft/ft between OW-9 and OW-9DA, completed to 85 feet bls in fractured bedrock. In OW-13D, completed to 115 feet bls, the upward gradient increases to 0.038 ft/ft. Furthermore, the upward vertical gradient within the fractured bedrock itself is also strong. A gradient of 0.066 ft/ft is measured between 65 and 115 feet bls within fractured bedrock at OW- 9D/13D, and a stronger gradient is even measured between 85 and 115 feet bls at 0.106 ft/ft at OW-9DA/13D. Gradients on the northern end of the area of impacts also exhibit similar patterns. There is an upward vertical gradient between the saprolite at OW-10 and the PWR zone at OW-10M. This gradient increases between OW-10 and OW-10D and is completed within the upper limits of fractured bedrock. A gradient of 0.008 ft/ft is measured between OW-10 and OW-10D. Beyond the small area of groundwater impacts to the north and south, nearly identical vertical gradients exist between the saprolite and PWR units, with 0.004 ft/ft downward at OW-11/11M and 0.003 ft/ft downward at OW-12/12M. As presented in the ACM, a rose diagram was produced using a fracture trace analysis of the straight-line segments of streams and tributary valleys. The resulting rose diagram shows a wide range of straight-line valley segment orientations. The strongest peak occurs at an orientation of between north 30 and 40 degrees east. Subsidiary peak orientations are located at north to north 10 degrees west, north 30 to 40 degrees west, and west to north 80 degrees west. The strongest null, at north 50 to 60 degrees west, is perpendicular to the strongest peak. 4 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan While fracture orientation is certainly important to groundwater flow in solid bedrock, the primary occurrence of shallow groundwater in the Piedmont is within the saprolite overlying bedrock. Here, groundwater flow occurs intergranularly, as compared to the flow of groundwater along fractures in bedrock. In this textural environment, the orientation of platey minerals, particularly micas that define foliation in the predecessor rock, has a stronger effect on groundwater flow than highly altered fracture remnants found in the saprolite. Considering this reality, a preliminary measurement of the orientation of remnant foliation has been made in the Landfill area. In the area where active soil cutting is taking place and where erosion has occurred along runoff channels, foliation and rare granitic veins or pegmatites are evident. Most of the observed foliation strikes between north and north 30 degrees east, and dips at about 20 to 60 degrees to the west. These strikes are subparallel to the dominant orientation of straight segments found in the vicinity. Water Quality Monitoring Program for Unit 1 Water quality at Unit 1 of the Landfill is monitored in accordance with the approved Revised Groundwater Monitoring Plan, dated March 1996, as modified by verbal and written communications between the City of Winston-Salem (City) and the NCDENR. Samples are collected from the following locations and analyzed in accordance with state approved laboratory methods. • Site Background Well – MW-1RR; • Closed Unlined Landfill – Performance wells (OW-3, OW-4, OW-10D, OW-12, OW-14D, and OW-17D), compliance wells (OW-6, OW-7DA, OW-11, and OW-13D); • Subtitle D (“Piggyback”) Landfill – MW-6, MW-6D, MW-7, MW-8, MW-9, and MW-11. • Four surface water locations – NBC-1, NBC-2, SW-3, and SW-4. • One leachate sample. The updated water quality monitoring plan incorporates those changes previously approved by DENR at the Closed Unlined Landfill. These changes consist of (1) revising the monitoring parameters and Appendix II frequency; and (2) including the background well (MW-1RR) into the performance monitoring network at the Closed Unlined Landfill. Proposed Water Quality Monitoring Plan The proposed water quality monitoring program for Unit 1 of the Landfill includes select detection and assessment wells, four surface water sampling locations and one leachate collection point. The monitoring plan has been updated in accordance with the NCDENR letter of September 22, 2008 and March 4, 2010. The Plan update includes sample locations (groundwater, surface water and leachate), sample frequency, sample collection; preservation shipment; analytical procedures; chain of custody control; quality assurance and quality control. These components are designed to ensure monitoring results that provide an accurate representation of water quality at the Landfill through effective detection monitoring and assessment of the efficacy of the MNA program. 5 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Sampling Locations The following paragraphs present the general rationale used to select groundwater (both detection and corrective action performance monitoring systems), surface water, and leachate sample locations. A substantial amount of geologic and hydrogeologic data has been developed at this site, much of which has been summarized in the Landfill permit documents. Well locations have been selected on the basis to provide water quality data from the uppermost aquifer beneath the facility, either in the unconsolidated saprolitic portion of the aquifer, as is the case for the Subtitle D Landfill, or from the fractured bedrock aquifer. The hydrogeologic and geologic characteristics of the facility and surrounding land, and the quantity, quality, and direction of groundwater flow were evaluated to determine the appropriate selection of monitoring wells. This evaluation considered site specific hydrogeologic information including aquifer thickness, groundwater flow rate, and groundwater flow direction, including seasonal and temporal fluctuations in groundwater flow. Also considered were unsaturated and saturated geologic units (including fill materials) overlying and comprising the uppermost aquifer; including but not limited to: thicknesses, stratigraphy, lithology, hydraulic conductivities, porosities and effective porosities, lithology of the aquifer and unsaturated zone; hydraulic conductivity of the aquifer and unsaturated zone; groundwater flow rates; minimum distance of travel; resource value of the aquifer; and nature, fate, and transport of any detected constituents. In addition, the distance of each proposed well relative to the waste unit (less than 250 feet) and the boundary of the property (50 feet or greater) was considered. Background Well Using the historical water table elevation data collected during multiple groundwater monitoring events at the facility, a background well was selected on the basis of hydraulic position in relation to the solid waste management units. The background well, MW-1RR, is hydraulically "upgradient" of the units and is located near former background monitoring wells OW-1 and OW-2. Historical and current water table elevation data indicates this well is consistently in an upgradient position. As discussed in detail as part of the Design Hydrogeologic Report, the uppermost aquifer at the Landfill is the saprolite derived from weathering of Ashe Formation rocks. The background well is completed in this uppermost aquifer, with a well screen that spans the water table, per North Carolina Department of Environment and Natural Resources. Please see Figure 1 for the locations of the background wells. Groundwater Monitoring Wells The proposed groundwater monitoring network for the Subtitle D cell includes background well MW-1RR and six side gradient or downgradient wells (MW-6, MW-6D, MW-7, MW-8, MW-9, MW-11). The proposed groundwater monitoring network for the unlined cell includes one background well (MW-1RR), six performance wells (OW-3, OW-4, OW-10D, OW-12, OW-14D, and OW-17D) and four compliance wells (OW-6, OW-7DA, OW-11, and OW-13D) (Figure 1). 6 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Surface Water Monitoring Points Samples will be collected from four surface water sample locations (NBC-1, NBC-2, SW-3, and SW-4) to monitor the quality of surface water on the Landfill property. SW-3 and SW-4 are located along South Branch Creek. A surface water sample representing background water quality along the northern side of the Landfill will be collected from the upstream end of North Branch Creek at NBC-1. A downstream surface water sample, NBC-2, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. Likewise, a surface water sample representing background water quality along the southern side of the Landfill will be collected from the upstream end of South Branch Creek at SW-3. Finally, a downstream surface water sample, SW-4, will be collected prior to the stream passing beneath the Norfolk-Southern Railroad. The location of these surface water sampling locations can be seen on Figure 1. Leachate Sampling Locations Leachate samples will be collected for analysis to determine the concentration of constituents released from the waste (if any). One leachate sample will be collected from the tanks. Leachate from the cells in Unit 1 is combined in this location before being pumped to the tanks where it is held until its release to the local treatment plant. The leachate sample will be analyzed for BOD, COD, temperature, conductivity, phosphate, pH, ammonia, Total Suspended Solids, sulfates, nitrates, mercury and Appendix I parameters. Summary The Subtitle D landfill monitoring wells, the surface water locations, and the background well will remain unchanged in location and analytical parameters from the previous monitoring program. The current monitoring program including these locations is performing properly. Table 1 summarizes the location, sampling type, parameters, and basic monitoring function for each of the sampling locations included in this Plan and presents a new set of groundwater wells associated with the closed, unlined portion of the Landfill Unit 1. Based on the extent of the property owned by the Commission, the rate at which groundwater flows, and the stable nature of the groundwater impacts, data gathered from these locations will adequately monitor the facility and track the status of groundwater remediation. The physical location of each sampling site is identified on Figure 1. Data Collection A brief description of the sampling frequency, monitoring functions, and types of data that will be collected and analyzed during the performance of this Plan is provided in this section. Analytical Parameters and Frequency The analytical parameters for groundwater at the detection wells, surface water, and leachate samples associated with the Subtitle D cell will be consistent with the historical monitoring and are unchanged except as described below. The parameters for the MNA performance monitoring program have been slightly adjusted to reduce the performance monitoring parameters or the frequency of monitoring for the 7 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan parameters in accordance with the NCDEDR letters of September 22, 2008 and March 4, 2010. The updated monitoring parameters will include Appendix II parameters, field parameters and laboratory parameters (Table 3). Performance monitoring includes analysis for Appendix II parameters at the closed unlined landfill which is conducted once every 2 years during the spring semiannual monitoring event. The two year frequency for Appendix II testing is in accordance with the NCDEDR letter dated March 4, 2010. Table 1 shows the frequency of monitoring at each well. This frequency will be sufficient to provide detection and performance monitoring considering: a. The extensive amount of down gradient property owned by the County; b. The existing impacts are limited to low level concentrations of VOCs; and c. The incorporation of additional parameters into the monitoring program (e.g. chloride, sulfate, dissolved oxygen, ORP and methane gas – which are indicators of the source contributor and geochemical indicators of natural attenuation). Groundwater Level Measurements During each required water quality sampling event, static groundwater levels (and total well depth) will be obtained from the proposed groundwater compliance monitoring wells immediately prior to purging. An electronic water level meter capable of measuring differences in water levels of 0.01 feet will be used to obtain these measurements. All measurements will be obtained from a reference point at the top of each PVC well casing which has an elevation established by a North Carolina registered land surveyor. The horizontal position of each well will be established using North Carolina Plane Coordinates. These data will be used to calculate the volume of standing water in each well and will provide information concerning well integrity (e.g., identify the presence of excessive siltation and casing breaches). All measuring equipment will be decontaminated before use at each well as established by Environmental Protection Agency (EPA) standards. Groundwater Direction and Flow Measurements Groundwater elevations will be calculated for each monitoring well using surveyed top-of-casing elevations prepared by a North Carolina registered land surveyor. Calculated potentiometric surface elevations for each sampling event will be placed on a scaled base map of the facility beside each respective monitoring point and contoured to produce a water table potentiometric surface map depicting potential groundwater flow direction(s) across the site. In addition, the estimated groundwater flow velocity will be calculated for each water quality sampling event. Using the static water table potentiometric data, effective porosities, hydraulic conductivity determined from slug tests, and the calculated hydraulic gradients for the respective sampling event, an estimated seepage (pore water) velocity will be calculated to continue to assess the potential for the migration of the low concentrations of VOCs. 8 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 1 Summary of Monitoring Sample Locations and Functions Sample ID Location Sample Type Area Monitored Parameters Analyzed Monitoring Function Spring Event Fall Event Current Proposed Ground-water Surface Water Leachate Closed Subtitle D Closed Unlined Appendix MNA(3) Appendix Background Data Release Detection Performance Monitoring I II I II MW-1RR X X X X X(1) X X X X MW-6 X X X X X X MW-6D X X X X X X MW-7 X X X X X X MW-8 X X X X X X MW-9 X X X X X X MW-11 X X X X X X OW-3 X X X X X(1) X X X X OW-4 X X X X X(1) X X X X OW-6 X X X X X X OW-7DA X X X X X X OW-10D X X X X X1 X X X X OW-11 X X X X X X OW-12 X X X X X1 X X X X OW-13D X X X X X X OW-14D X X X X X(1) X X X X OW-17D X X X X X(1) X X X X NBC-1 X X X X NBC-2 X X X X SW-3 X X X X SW-4 X X X X Leachate Tank X X X X4 X (1) Samples will be monitored for Appendix II constituents every other spring monitoring event beginning in spring 2011. Detected Appendix II parameters will be monitored independently for 4 events at all wells at the unlined landfill. (2) Detail for performance monitoring is listed in Table 3. (3) Additional leachate parameters include BOD, COD, nitrate, sulfate, phosphate, TSS, ammonia and mercury. 9 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Well Construction Each downgradient well is installed with a screened interval of Schedule 40 PVC well screen with a 0.01-inch slotted opening. The construction of the groundwater monitoring wells is in general accordance with the North Carolina Well Construction Standards. Table 2 presents groundwater monitor well construction details. A schematic showing well-specific construction details for each well is provided in the Appendix of this Plan. Table 2 Monitoring Network Well Construction Details Well Grade Top of Casing Well Depth Screened Interval Screened Elevation Spring 2010 Water Levels (FT MSL) (FT MSL) (FT BLS) (FT MSL) Depth TOC FT MSL MW-1RR 893.60 896.82 60.0 45.0 - 60.0 848.6 - 833.6 41.08 855.74 MW-6 865.60 867.78 35.0 20.0 - 35.0 845.6 - 830.6 26.84 840.94 MW-6D 865.60 867.89 64.5 54.5 - 64.5 811.1 - 801.1 27.32 840.57 MW-7 843.10 845.33 25.0 10.0 - 25.0 833.1 - 818.1 14.88 830.45 MW-8 833.80 836.91 20.0 5.0 - 20.0 828.8 - 813.8 10.25 826.66 MW-9 840.40 842.31 30.0 15.0 - 30.0 825.4 - 810.4 20.58 821.73 MW-11 843.20 845.23 30.0 15.0 - 30.0 828.2 - 813.2 17.85 827.38 OW-3 817.75 820.13 16.0 6.0 - 16.0 811.8 - 801.8 8.53 811.60 OW-4 806.83 809.37 16.0 6.0 - 16.0 800.8 - 790.8 5.52 803.85 OW-6 824.74 827.12 27.0 12.0 - 27.0 812.7 - 797.7 16.28 810.84 OW-7DA 798.80 801.52 115.0 110.0 - 115.0 688.8 - 683.8 4.44 797.08 OW-10D 817.30 820.09 80.0 75.0 - 80.0 742.3 - 737.3 18.14 801.95 OW-11 804.47 806.69 16.0 6.0 - 16.0 798.5 - 788.5 2.68 804.01 OW-12 798.40 800.14 15.0 5.0 - 15.0 793.4 - 783.4 3.88 796.26 OW-13D 803.80 806.41 115.0 110.0 - 115.0 693.8 - 688.8 4.64 801.77 OW-14D 801.20 803.95 80.0 70.0 - 80.0 731.2 - 721.2 3.03 800.92 OW-17D 798.80 801.54 80.0 70.0 - 80.0 728.8 - 718.8 4.53 796.87 FT – Feet MSL – Mean Sea Level BLS – Below Land Surface TOC – Top of Casing Analytical Procedures Test Parameters and Methods Low-flow purging and sampling techniques are the preferred methodology for purging and sampling monitoring wells. Dedicated pumps will be utilized where available and otherwise decontaminated peristaltic or bladder pumps will be utilized. The pump will be positioned within the screened interval and will be pumped at such a rate that minimal drawdown will occur in the well. This is usually between 100 and 500 milliliters per minute (ml/min). 10 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Table 3 Updated MNA Monitoring Parameters and Methods Parameter Method or Equipment Used Monitoring Frequency Field Parameter Measurements Temperature Water quality meter Semiannual pH Water quality meter Semiannual Conductivity Water quality meter Semiannual Oxidation Reduction Potential (ORP) Water quality meter Semiannual Dissolved Oxygen (DO) Downhole or flow through cell meter Semiannual Turbidity turbidity meter Semiannual Water Elevation Electronic Water Level Indicator Semiannual Ferrous Iron SM 3500-Fe or Field Meter Semiannual Laboratory Analysis Hydrogen, sulfide, alkalinity, and volatile fatty acids Every 5 years from fall 2006 Methane, ethane, and ethane Every 3 years from fall 2006 Appendix I VOCs EPA Method 8260 Semiannual Appendix I Metals Varies Semiannual Appendix II Parameters* Once Every Two Years Nitrate-N EPA 352.1/353.2/353.3 Semiannual Sulfate EPA 375.4/375.2/300.0 Semiannual Chloride EPA 325.2/325.3/310.0 Semiannual Total Organic Carbon SM 5310B/310.2 Semiannual Note: * Four independent samples will be analyzed for any detected Appendix II Parameter from all Performance wells to establish background levels for the compound Once drawdown has stabilized, a flow through cell meter will be connected to the water discharge outlet to record field measurements [pH, temperature, specific conductance, dissolved oxygen (DO), salinity, and oxidation reduction potential (ORP)] to determine when a representative sample can be collected. These measurements will be obtained from a field- calibrated instrument in accordance with the manufacturer’s specifications and industry standards. The flow cell meter will log the geochemical changes of the purge water and signal when they become stabilized. Well purging efforts will continue until the following stabilized conditions occur: pH ±0.2 units, DO ±0.2 mg/l (or ± 20% whichever is greater), specific conductance ±5%, ORP ±10 millivolts (note this compound is optional and is not required). At that time, the flow cell will be disconnected allowing the water quality samples to be collected directly from the discharge tube under low-flow conditions (<100 ml/min). The parameters to be incorporated into the MNA performance-monitoring program have been selected to track contaminant concentrations (including daughter products) and key indicators of natural attenuation processes, and detect any new potential impacts. 11 City/County Utility Commission | Hanes Mill Road Landfill – Water Quality Monitoring Plan Proposed Water Quality Monitoring Plan Field measured parameters include pH, specific conductivity, temperature, dissolved oxygen (DO), and oxidation reduction potential (ORP) which serve as indicators of natural attenuation processes, as well as indicators of general water quality. Table 3 presents the performance monitoring parameters and methods. Sample Preservation and Shipment All samples will be collected using the containers, preservatives, and holding times appropriate for each respective parameter being analyzed. The proper chain of custody and sample blank (trip blank and equipment blank) procedures will also be followed accordingly. In addition to providing evidence of attenuation, data (groundwater elevation measurements) will be collected to determine the direction and rate of any contaminant migration. All samples will be analyzed for the targeted parameters by a laboratory certified by the State of North Carolina. Surface water samples will be collected according to the “Environmental Investigations Standard Operating Procedures and Quality Assurance Manual”, May 1996, Sections 5 and 10. Samples will be collected directly into the sample containers facing upstream at mid-depth at the center of the channel (except VOCs). Surface water samples for VOC analysis will be collected using decontaminated glass lab containers and transferred to 40 ml vials leaving no headspace. Care will be taken not to disturb the bottom sediment and not to displace the preservative from a pre-preserved sample container. The area of the surface water samples will be selected according to the location of the greatest degree of cross-sectional homogeneity. If available, the surface water sample locations will be selected immediately downstream of riffle areas to ensure good vertical mixing. Tributaries will be sampled as near the mouth as feasible. Temperature, pH, turbidity, and conductivity will be measured at each surface water sample location. Surface water samples will only be collected if flowing water is noted at the time of sampling (i.e. not stagnant water). Reporting The data from each semiannual sampling event will be evaluated and reported to the NCDEQ along with the regular semiannual groundwater reports. At the end of a two-year period, the groundwater remediation status will be re-evaluated. 12 Landfill Gas Monitoring Plan Hanes Mill Road Landfill Winston-Salem, North Carolina Revised June 2016 This page intentionally left blank. City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Contents Introduction ................................................................................................................................ 1 Background Information ............................................................................................................. 2 General .................................................................................................................................. 2 Site Information ...................................................................................................................... 2 Landfill Gas Overview & Regulatory Action Levels ..................................................................... 3 Landfill Gas Monitoring .............................................................................................................. 4 Proposed Landfill Gas Monitoring Procedure.......................................................................... 4 Permanent Monitoring Station Design and Installation ........................................................ 4 Gas Migration Monitoring .................................................................................................... 2 Reporting of Data and Record Keeping ............................................................................... 0 Continuous Monitoring of On-Site Structures ...................................................................... 0 Schedule for Installation of Monitoring Elements .................................................................... 0 Maintenance and Calibration of Monitoring Elements ............................................................. 0 Maintenance of Permanent Monitoring Stations .................................................................. 0 Calibration of Portable Monitoring Instruments .................................................................... 1 Contingency Plan ....................................................................................................................... 2 Contingency Plan Guidelines .................................................................................................. 2 Contingency Plan - On-site Structures .................................................................................... 2 Immediate Action ................................................................................................................ 2 Action within 7 Days ............................................................................................................ 3 Action within 60 Days .......................................................................................................... 3 Contingency Plan - Facility Property Boundary ....................................................................... 3 Immediate Action ................................................................................................................ 3 Action within 7 Days ............................................................................................................ 3 Action within 60 Days .......................................................................................................... 4 LFG Control System Installation and Monitoring ........................................................................ 6 Passive Gas Control System .................................................................................................. 6 Surface Monitoring and Observations ................................................................................. 6 Subsurface Pressure .......................................................................................................... 6 Proximity ............................................................................................................................. 6 Active Gas Control System ..................................................................................................... 7 Gas Collection System ........................................................................................................ 7 i City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contents Gas Utilization or Control System ....................................................................................... 7 Safety ........................................................................................................................................ 8 Tables Table 1 Compliance Levels for Methane ................................................................................... 3 Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ........................................... 4 Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 ........................................ 4 Table 4 Contingency Plan Contacts .......................................................................................... 2 Figures Figure 1 Drawing 00C-02 Gas Monitoring Wells ........................................................................ 5 Figure 2 Typical Methane Probe Construction........................................................................... 1 Figure 3 Groundwater Surface Contour Map ............................................................................. 3 Appendices Appendix A - Field Data Form Appendix B – Boring Logs ii City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Introduction Introduction The purpose of this Landfill Gas Monitoring Plan (LGMP) is to provide a management practice for the monitoring and control of landfill gas generated by the Hanes Mill Road Landfill. Following approval of this LGMP by the North Carolina Department of Environmental Quality (NCDEQ) Division of Waste Management (DWM), a routine methane monitoring program will be implemented at the landfill. Once final closure of the unit is complete, the monitoring program will continue in accordance with NC regulation, 15A NCAC 13B .1627 (d). At the present time, this term is for 30 years. Following approval, this plan will be placed in the landfill operating record and shall remain open for revisions throughout the active life of the landfill, as well as after landfill closure is complete. All changes to this plan will be submitted to NCDEQ DWM as they are implemented. 1 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Background Information Background Information General The Hanes Landfill is located off Hanes Mill Road approximately five miles north of the City of Winston-Salem, North Carolina (the City) and is operated under North Carolina NCDEQ DWM Permit No. 34-02.The facility consists of two major units: the original landfill unit consisting of the unlined and “piggyback” unit, which closed in 2005, and an expansion area which is currently active. The closed landfill contains an unlined and a lined MSW unit and is located on approximately 181 acres. The landfill expansion area occupies approximately 90 acres to the west of Grassy Creek and the Norfolk Southern Railroad. Phase 1 of the expansion area was permitted, constructed, and begin accepting waste in May 2005. The proposed Phase 2 of the expansion area is located immediately north of Phase 1 and consists of approximately 22 acres. Filling at the landfill will be conducted by the area method in which the waste will be placed in lifts of approximately 10 feet in height which is then covered with soil (or approved alternative cover) on a daily basis. Site Information Land use is primarily limited to residential development to the north and west of the landfill expansion area. To the east of the area are the Norfolk Southern Railroad line, the closed landfill area, and a combination of commercial and residential developments. The headquarters for Sara-Lee Corporation is located along the southern edge of the landfill expansion area; land to the south is also being used for other commercial endeavors, as well as residential development. 2 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Overview & Regulatory Action Levels Landfill Gas Overview & Regulatory Action Levels One of the byproducts of landfilling municipal solid waste is landfill gas which is generated by the anaerobic decomposition of waste within the landfill. Landfill gas typically consists of methane (CH4) and carbon dioxide (CO2), with trace amounts of oxygen (O2), water (H2O), nitrogen (N2), hydrogen sulfide (H2S), and other gases. The amount and rate of generation of landfill gas is affected by several factors, including the following. • Total refuse tonnage in-place. • Moisture content of the refuse. • Age of the refuse. • Organic composition and pH value of the refuse. • Method and degree of compaction of the refuse. • Type and amount of cover material used. The concentration of the landfill gas varies according to site-specific conditions; however, landfill gas compositions of 30-53 percent methane (CH4) and 34-51 percent carbon dioxide (CO2) are common. The primary health and safety concern with landfill gas in the immediate area of the landfill is the explosive characteristic of methane. Methane concentrations in between 5 and 15 percent by volume in air (5% is referred to as the “Lower Explosive Limit” or LEL, and 15% is referred to as the Upper Explosive Limit or UEL) are able to create an explosion hazard and can also propagate a flame. Landfill gas can travel in all directions, taking the path of least resistance. Landfill gas moves from areas of higher concentrations to areas of lower concentrations (diffusion), or from higher gas pressure zones to lower gas pressure zones (convection). Subsurface geologic and hydrogeologic conditions contribute greatly to the potential for gas migration. When landfill gas migration is taking place, on-site and nearby structures are at risk of receiving migrating gas due to confined spaces in or under the buildings. Landfill gas can enter buildings through cracks in the foundation or subsurface utility services. Lack of ventilation may result in the buildup of methane concentrations to explosive limits. In an effort to eliminate the potential hazards associated with the migration of landfill gas, NCDEQ has promulgated regulations (15A NCAC 13B .1626 (4)) , which require owners and/or operators of all municipal solid waste landfill facilities (MSWLF) to monitor methane at the facility property boundary and on-site structures. Table 1 below provides the present regulatory limits for methane at MSWLF sites. Table 1 Compliance Levels for Methane Location Lower Explosive Limit (% LEL) Maximum Methane Concentration in Air Property Boundary 100% 5% Facility Structures 25% 1.25% 3 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Landfill Gas Monitoring Proposed Landfill Gas Monitoring Procedure To provide a means of monitoring methane gas at the landfill, permanent gas migration monitoring stations have been installed along the perimeter of the active and closed landfill areas. These stations are monitored on a quarterly basis. Additional stations will be installed in the Phase 2 expansion area as needed. Permanent Monitoring Station Design and Installation Permanent monitoring stations have been installed around the active and closed landfill. All the wells are for detection monitoring. Figure 1, drawing 00C-02 Gas Management Plan, shows the monitoring wells at the landfill. ACTIVE LANDFILL EXISTING STATIONS Eight permanent monitoring stations (MM-1 through MM-8) have been installed along the permit boundary for Phase 1 of the landfill expansion at not more than 500-foot intervals (see Drawing C-8). Three additional wells have been installed and a fourth is in the process of being installed for Phase 2. The well locations were placed between the permitted waste boundary and property lines. No wells are shown between the active landfill and Grassy Creek since this is interior to the property line and Grassy Creek acts as a cut-off feature. The following tables summarize the existing and proposed installation details for each gas probe. Figure 2 shows the typical construction details for a permanent methane monitoring probe. Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 Station ID Number Total Depth Screened Interval MM-1 7 Feet 3 - 7 Feet MM-2 14 Feet 2 - 14 Feet MM-3 14 Feet 2 - 14 Feet MM-4 2.5 Feet 1.5 - 2.5 Feet MM-5 4 Feet 2 - 4 Feet MM-6 5 Feet 2 - 5 Feet MM-7 5 Feet 2 - 5 Feet MM-8 4 Feet 2 - 5 Feet MM 9 7 Feet 2 – 7 Feet MM 10 10 Feet 2 – 10 Feet MM 11 40 Feet 2 – 40 Feet MM-12 To be installed Table 3 Expansion Landfill Site Proposed Methane Wells – Phase 2 Station ID Number Total Depth Screened Interval MM-12 45 Feet 2 - 45 Feet Notes: (1) See boring logs for subsurface lithology (Appendix B) (2) See potentiometric surface map for depth to groundwater 4 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 0 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Figure 2 Typical Methane Probe Construction 1 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Station depths were based on geological formations logged during the installation of the nearest ground-water monitoring wells, the proposed depth of waste, and the recorded seasonal high ground-water elevations. All existing stations were installed with screens beginning at the elevation of the bottom of waste, or slightly above the top of the seasonal low water table (whichever is higher) and extending upward to approximately 2 feet below grade. Future monitoring stations will be installed using the same criteria. The final design depths of the future stations will be determined in the field during borehole installation. Refer to Figure 3, Groundwater Surface Contour Map, for the depth to groundwater. CLOSED LANDFILL EXISTING STATIONS Twenty-two permanent monitoring stations (MM-B through MM-K, MM-P through MM-U, MM-W through MM-Z, and MM-AA through MM-BB) have been installed along the boundary for the closed landfill. ACTIVE LANDFILL FUTURE STATIONS The gas monitoring stations for Phase 2 of the active landfill will be installed using 4.25-inch inside diameter (ID) hollow stem augers. Once at the desired depth, a 1-inch, Schedule 40 PVC gas probe will be inserted through the center of the augers. Each probe will be constructed with flush-threaded joints with a screened interval of 0.010-inch, factory-slotted well screen. Coarse- grained silica gravel will be placed around the screen interval by gravity settling. The gravel pack will extend to a minimum of 6 inches above the top of the screen. A 6-inch minimum bentonite seal will be placed immediately above the gravel pack. The remaining probe annulus will be sealed to surface grade using a Portland Type I cement mixture. Each probe station will be protected above grade by a 4-inch square steel locked well box secured in place with a 2- foot by 2-foot concrete pad. The top of each well probe will be fitted with a laboratory-type stop- cock valve for gas sample collection. The outside of each station will be fitted with an identification tag indicating the station number, installation date, driller name and registration, completion depth, and screened interval. Gas Migration Monitoring Reading of the permanent monitoring stations and on site structures will be conducted on a quarterly schedule. As per existing regulations, the monitoring frequency of individual stations may be increased if methane is detected above the LEL. Sampling procedure will follow the manufacturer’s instructions. All perimeter gas stations shall be monitored for the following parameters. • Combustible Gas (methane) - with a Landtec GEM 2000 (or equivalent).The station shall be sufficiently evacuated with the sample pump so that methane concentrations are constant for at least 30 seconds. The large scale (0-100 percent methane-in-air) shall be used first. If readings are below 5 percent, the reading will be obtained using the smaller (0-5 percent methane-in-air) scale. Information from the monitoring will be recorded on the field data form (Appendix A). Any readings recorded at or above the LEL for methane will be immediately verified and reported as described in Section 5.0 of this plan. 2 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring This page intentionally left blank. 4 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Reporting of Data and Record Keeping All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix A). Copies of the completed quarterly reports, including the original completed field data forms, will be kept on-site in the Landfill Operating Record for a minimum of two years. A separate calibration log for the on-site instrument will be kept on-site and will contain the following information. • Date and time of calibration. • Name of person calibrating. • Serial number and model number of instrument. • Type of calibration. • Results of calibration. Continuous Monitoring of On-Site Structures Select on-site buildings will be equipped with a Sierra Monitor 2001 series (or equivalent) continuous monitoring device to detect combustible gas concentrations that may accumulate inside the structures. The Sierra Monitor 2001 series is rated to detect a wide range of combustible gases and has a methane detection range of 500 to 10,000 parts per million (ppm) (.05 to 1.0 percent methane- in-air). The monitor should be installed in an area of the structure where methane gas is most likely to accumulate. Any verifiable detection of methane in the structures will be addressed and reported in accordance with Section 5.0 of this LGMP. Schedule for Installation of Monitoring Elements When the City determines that additional permanent monitoring stations are needed, this station will be installed and documentation will be submitted to the NCDEQ DWM after installation. Maintenance and Calibration of Monitoring Elements The City conducts the following maintenance schedule and calibration procedures for the gas monitoring elements at the landfill. Training of personnel is conducted when necessary. Monitoring of the Phase 2 landfill area will be incorporated into this schedule. Maintenance of Permanent Monitoring Stations A visual inspection of the permanent stations will be conducted quarterly in conjunction with the monitoring events. The inspection schedule will increase with any increases in the monitoring schedule. The condition of following elements will be inspected. • Station label. • Protective casing and concrete pad. • Lock. • Station surroundings including standing water and vegetation. Any abnormalities regarding the condition of the station will be noted on the field log and immediately addressed. 0 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Landfill Gas Monitoring Calibration of Portable Monitoring Instruments CONTINUOUS MONITORING DEVICES Continuous monitoring devices will be maintained and calibrated according to the manufacturers’ recommendations. Maintenance and calibration will be conducted quarterly and will include the following tasks. • Verification of power to the monitor. • Ensuring that there is no interference of air flow to the monitor. • Exposing the sensor to a sample of calibration gas per the manufacturer's recommended procedure to verify that the monitor is calibrated correctly. PORTABLE MONITORING INSTRUMENTS Portable monitoring instruments such as the Landtec GEM 2000 will be maintained and calibrated according to the manufacturer's recommended procedure. For a detailed description of the maintenance and calibration procedures, the instruction manual should be consulted. 1 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Contingency Plan The City will implement the following contingency plan if the landfill gas readings at any monitoring location exceed the limits set by regulations (see Section 3.0 of this plan). Contingency Plan Guidelines If allowable maximum limits for methane gas are exceeded at the facility property boundary or in on-site structures, the City will take the following steps. Step 1: Immediately take all necessary steps to ensure protection of human health and notify NCDEQ. Step 2: Within seven days of detection, place the methane gas levels detected and a description of the steps taken to protect human health in the operating record. Step 3: Within 60 days of detection, develop and implement a remediation plan that describes the nature and extent of the problem and proposed remedy for the methane gas releases, place a copy of the plan in the operating record and notify NCDEQ that the plan has been implemented. Consistent with the above requirements, notifications will be made either in person or by telephone followed by a facsimile transmission or letter. The City will also contact the following agencies or personnel as necessary. Table 4 Contingency Plan Contacts Agency or Personnel Contact Telephone Number City of Winston-Salem Solid Waste Administrator 336-727-7310 City of Winston-Salem Solid Waste Engineer 336-734-1506 City of Winston-Salem Landfill Operation Superintendent 336-430-6172 NCDEQ – Emergency Notification Environmental Specialist 336-776-9672 Fire Department -- 336-727-8000 Contingency Plan - On-site Structures The following contingency plan for responding to the detection of excessive methane gas quantities detected in all onsite buildings will be implemented by the City. Immediate Action • The affected building(s) would be vacated for a period of time determined by the appropriate emergency officials and all necessary steps will be taken to ensure protection of human health. • The landfill operations superintendent, the occupants of the building(s), and the personnel listed in Section 5.1 will be contacted. • Notify NCDEQ. 2 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan • Following the evacuation, the building(s) will be monitored by City personnel to determine the extent and source of the methane. Remedial actions such as sealing cracks or connections would be taken as necessary. Action within 7 Days The landfill staff will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.2.1 of this LGMP. Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long term remedial action(s). IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the Plan has been implemented. Contingency Plan - Facility Property Boundary The City's proposed contingency plan for responding to excessive methane gas quantities at the facility property boundary is provided below. Immediate Action • Landfill personnel will be directed away from the affected area and all necessary steps will be taken to ensure protection of human health. • The affected area will be monitored daily for a period of time to confirm the methane concentration. • If monitoring reports are positive, areas adjacent to the affected zone (including the property line, utility trenches, and off-site buildings and structures) shall be monitored or screened by designated personnel. • If the methane gas quantities exceed the LEL at the facility boundary, the landfill manager and the personnel listed in Section 5.1 of this plan, may be contacted. • Notify NCDEQ. Action within 7 Days The landfill manager will prepare and place in the operating record a brief report to include, at a minimum, the following information. • Results of original and any additional monitoring. • Summary of actions taken included in Section 5.3.1 of this LGMP. 3 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan Action within 60 Days PREPARE A REMEDIATION PLAN A remediation plan will be prepared to address at least the following issues. • Nature and extent of the problem. • Proposed long-term remedial action(s) such as installation of passive or active gas control system. A copy of the LGMP will also be placed in the landfill operating record for the facility. NCDEQ will be notified that the remediation plan has been implemented. BAR-HOLE PROBE INSTALLATION AND MONITORING PROCEDURE Bar-hole probes may be temporarily installed as a remediation plan and monitored along the perimeter boundary of the landfill. Bar-hole probes may be used for identifying and tracking methane migration plumes, as described in Section 5.0, and as a substitute monitoring method for damaged or malfunctioning permanent probes. Prior to conducting bar-hole probing, the area will be checked for any subsurface utilities, conduits, or pipelines. If water or mud covers the desired probe location, then the probe will be offset to a nearby dry portion of the permit boundary or temporarily eliminated from the monitoring round. All precautions shall be taken to eliminate the introduction of moisture into the monitoring instrument. Any abnormalities in the probe location will be noted on the field data form (refer to Appendix A). The bar-hole procedure will involve pushing a 1/2-to 3/4-inch diameter metal rod a minimum of 2-3 feet into the subsurface soils. Upon removal of the metal rod, a probe connected to Landtec GEM 2000 or equivalent will be immediately inserted into the hole and sealed to minimize air infiltration into the sample. A measurement of the sample, along with other pertinent data, will be taken and recorded on the field data form located in Appendix A. Readings from the probe hole will be taken first with the instrument in the “HIGH” or 0-100 percent methane-in-air range. If a reading above 5 percent cannot be maintained during evacuation for at least 30 seconds, then the measurement shall be repeated with the instrument in the “LOW” or 0-5 percent methane-in-air (0-100 percent of the LEL) range. Upon completion of the monitoring, the probe hole will be backfilled with native soil. If concentrations of methane are measured at or above the LEL, additional bar-hole probes will be installed to assess the lateral extent of the migration. The additional probes will be placed in a radial pattern starting at the initial probe location and working in 5-foot increments outward. The pattern will continue until readings of 0 percent methane are obtained. Information from this monitoring procedure will be recorded on graph paper to determine the extent of the migration. The information will be submitted to NCDEQ in the Semiannual Ground-Water Monitoring Report. If it is determined that off-site migration exists above the LEL, the information, along with any proposed mitigation measures, will be submitted in accordance with Section 5.0 of this LGMP. 4 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Contingency Plan The bar-hole probe equipment will be maintained between monitoring events. Maintenance associated with the bar-hole probe monitoring includes ensuring plunger bar is clean and free of damage. IMPLEMENTATION OF THE PLAN NCDEQ will be notified that the remediation plan has been implemented. 5 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring LFG Control System Installation and Monitoring If necessary, a gas control system can be installed as a mitigation measure to prevent the off- site migration of landfill gas. The City understands that the installation of an active gas collection system may be required at the landfill expansion area to control non-methane organic carbon (NMOC) emissions. Any active gas collection system required will be integrated into this LGMP after it is installed. The results of any landfill gas monitoring event, described in Section 4.0 of this LGMP, will be presented to NCDEQ for review. If a LFG control system is required at the landfill to control or prevent off-site gas migration, the City can pursue one of the following two alternatives. • Passive Gas Control System, or • Active Gas Control System. Passive Gas Control System Passive vents can release some of the pressure of landfill gas within the waste, thus reducing the amount of localized gas migration. A typical passive gas control system utilizes gas "vents" that are simple in design and require low maintenance. A passive gas control system has been proposed for implementation during the closure of the landfill. A passive gas control system consists of gas vents installed in the refuse. The passive vents will vent freely into the atmosphere, thereby reducing subsurface pressure and controlling local lateral migration of the gas. The vent wells should be designed and spaced so that the system could be converted into an active gas control system, if necessary, in the future (see Section 6.2). The locations of the passive vents are determined using any one, or a combination, of the following three methods. Surface Monitoring and Observations Observations of the surface conditions at the site can aid in determining the best location for passive vents. Venting cracks, stressed vegetation, and odors are all indicative of gas migrating through the soil cover. In addition, monitoring of the surface may be conducted to locate less visible emission sources. Subsurface Pressure If feasible, subsurface soil pressure measurements can be taken within the landfill permit limits to determine areas of increased pressure. Gas vents can then be installed to release the pressure. Proximity Passive vents should be installed in close proximity to the area of concern. One or more vents can be installed next to the permanent station, bar-hole probe, or facility structure that contained methane above the designated limits. Additional vents may be installed until the area of concern is mitigated. 6 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan LFG Control System Installation and Monitoring The passive gas system performance monitoring is conducted on a quarterly basis and increased to a monthly basis if necessary. Monitoring methods are described in Section 4.0 of this Plan. Active Gas Control System An active gas control system consists of a collection system plus a utilization or control system. The design of the system components depends upon the site-specific conditions. The main components of an active gas collection system are the gas collection system and the gas utilization or control system. Gas Collection System The main components of a gas collection system are gas wells, gas collection headers with appropriate fittings and supports, and the moisture/condensate removal and collection system. It is anticipated that vertical wells will be used rather than horizontal wells. Horizontal wells require installation during filling, while vertical wells may be installed at any time. The locations of the vertical wells will be determined in a manner similar to locating the passive gas control vent system. Gas Utilization or Control System Two common types of gas utilization or control systems are LFG flare systems and cogeneration systems. Selection of the system will depend on several factors including LFG flow rates, quality, and cost-benefit analysis. Measurements will be performed to determine whether the methane can be economically collected and utilized as a fuel source. If economical, a cogeneration system may be installed. Typically, a cogeneration system includes a gas treatment plant, gas turbine(s) or internal combustion engine(s) and generating set(s), and other ancillary equipment. If the methane cannot be collected and utilized economically, a system consisting of multiple open gas flare units will be installed. A flare system will typically consist of gas blower(s), flares, moisture separators, and a detailed safety system. 7 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety Safety Prior to beginning a monitoring procedure, the landfill technician must understand the potential dangers associated with landfill gas. Not only is landfill gas explosive, it can also present the following other hazards. • Landfill gas may cause asphyxiation through oxygen displacement. Proper procedures must be followed when entering confined spaces which may be potential receptors of migrating landfill gas. • Some of the possible trace contaminants associated with landfill gas, such as hydrogen sulfide (H2S), are extremely toxic. Technicians must be trained in the indicators of H2S such as its recognizable odor (rotten egg) at low concentrations. At a minimum, the following items should be addressed by the technician, in addition to any site- specific safety procedures to reduce the chance of injury. • Be aware of the hazards of landfill gas as mentioned above. • Practice confined space entry procedures when entering structures that have been evacuated due to the possible presence of landfill gas in confined space. • Always practice the “buddy” system (i.e., work with a partner who remains outside of the area of possible exposure) when monitoring for landfill gas. • Know where all firefighting equipment (i.e., extinguishers, hoses, etc.) is stored and ensure that it is well maintained. • Determine whether additional personal safety equipment is necessary. • Do not smoke or allow others nearby to smoke while monitoring for landfill gas, or at any time when near landfill waste. • Know how the monitoring instruments work and how to operate and calibrate them properly. • Determine where all nearby subsurface utilities are prior to bar-hole probing. • Do not use odor as a primary indicator of landfill gas migration. • Inform the landfill manager or your supervisor of any possible hazards, no matter how small they may appear. 8 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Safety This page intentionally left blank. 9 City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices A Appendix A - Field Data Form City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. ! " #$ ! % & ' % ( ) * + , - ) * + . / ! ) * + 0 ) * * * # # % 1 % ' $ 2 ' $ ! 3 4 5 ! ! 1 4 * ! . , ! 0 6 7 8 9 : * + ; 4 < * * * . # < Th i s p a g e i n t e n t i o n a l l y l e f t b l a n k . City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices B Appendix B – Boring Logs City/County Utility Commission | Hanes Mill Road Landfill - Landfill Gas Monitoring Plan Appendices This page intentionally left blank. This page intentionally left blank.