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HomeMy WebLinkAbout1302_CabarrusCountySolidWasteFacility_LandfillGasMonitoringPlan_DIN27276_2017Cabarrus County Construction and Demolition Debris Landfill Phase No. 3 Expansion Landfill Gas Monitoring Plan Revised January 2017 i Table of Contents 1. Introduction ................................................................................................................... 1-1 1.1 Purpose ......................................................................................................................................................................... 1-1 1.2 General Characteristics of LFG and Methane Generation ........................................................................ 1-1 2. Regulatory Background .................................................................................................. 2-1 2.1 Introduction ................................................................................................................................................................ 2-1 2.2 C&D Landfills and North Carolina Regulations ............................................................................................ 2-1 3. Gas Control Plan ............................................................................................................ 3-1 3.1 Frequency of Routine Monitoring ..................................................................................................................... 3-1 3.2 Monitoring Wells ...................................................................................................................................................... 3-1 3.3 Staffing ........................................................................................................................................................................... 3-1 3.4 Monitoring Procedures .......................................................................................................................................... 3-1 3.4.1 Monitoring Times ......................................................................................................................................... 3-2 3.4.2 Sampling Procedures .................................................................................................................................. 3-2 3.5 Record Keeping .......................................................................................................................................................... 3-3 4. Detection Plan ............................................................................................................... 4-1 4.1 Actions if Regulatory Limits Detected in Structures ................................................................................. 4-1 4.2 Actions if Regulatory Limits Detected at Monitoring Wells ................................................................... 4-1 4.3 Compliance Action Plan ......................................................................................................................................... 4-2 4.3.1 Immediate Action ........................................................................................................................................ 4-2 4.3.2 Actions Within Seven Days ..................................................................................................................... 4-2 4.3.3 Actions Within Sixty Days ....................................................................................................................... 4-3 4.4 Public Relations and Information ...................................................................................................................... 4-3 List of Sheets Sheet 1 GW and LFG Monitoring Network ..................................................................................................... Pocket 1-1 Section 1 Introduction Landfill gas (LFG) is a natural by-product of the anaerobic decomposition of landfilled bio- degradable waste. Under aerobic conditions, LFG can ignite and propagate fires, presenting a danger to human health and the environment and therefore must be monitored. For these reasons, LFG is regulated by Federal and North Carolina state legislation. This Plan describes the systems and programs needed to fulfill federal and state regulations concerning LFG. Methane and hydrogen sulfide are two gases that could potentially be generated from wastes in a MSW and a C&D landfill. The Plan for the facility includes LFG monitoring near the facility boundary through monitoring wells and all structures at the Site. The Landfill Units at the Site that are covered by this Plan include: The active C&D Landfill and expansions – Permit 1302-CDLF-2006, The inactive/closed Units 2 and 3 MSW Landfill (including CDLF over MSW) – Permit 1302- MSWLF and 1302-CDLF-1998, The inactive/closed Unit 1 Landfill – Permit 1302-MSWLF-1974. 1.1 Purpose This Plan fulfills the requirements set forth in Rule .0544(d) for monitoring LFG. This Plan: Describes the necessary LFG monitoring systems, Sets forth the monitoring procedures and programs, and Identifies the actions needed if levels of methane or hydrogen sulfide exceed regulatory limits. 1.2 General Characteristics of LFG and Methane Generation LFG is composed of approximately 50 percent methane in contrast to natural gas which consists of approximately 95 percent methane. What makes LFG a source of environmental pollution is its odor, its potentially explosive properties, its potential for asphyxiation, and its contribution to global warming. LFG programs which focus on the environmental hazards of landfill gas include systems to monitor the migration of gas and control or neutralize its environmental impacts. Landfill gas from MSW landfills is typically composed of 50 to 55 percent methane, 45 to 50 percent carbon dioxide, and less than one percent non-methane organic compounds. These individual gases remain co-mingled and do not naturally separate. Because C&D wastes do not contain large quantities of organic matter, methane and carbon dioxide should not be a concern. However, if a significant amount of gypsum wallboard is present in C&D waste, hydrogen sulfide may potentially be produced, particularly if moisture is introduced into the waste. 2-1 Section 2 Regulatory Background 2.1 Introduction Because of the real and potential dangers from LFG, particularly hydrogen sulfide or to a lesser extent methane in LFG generated from C&D landfills, to the public health and safety and to the environment, existing state regulations, as described in Rule 15A NCAC 13B .0544 (d) (1 through 5), require owners of C&D landfills to monitor and, if necessary, control it. 2.2 C&D Landfills and North Carolina Regulations Methane gas is explosive when present within the range of 5 to 15 percent by volume in air. When present in concentrations greater than 15 percent, the mixture will not explode. The 5 percentage mixture is referred to as the Lower Explosive Limit (LEL) while the 15 percentage concentration is referred to as the Upper Explosive Limit (UEL). Hydrogen sulfide is explosive when present within the range of 4 to 44 percent by volume in air. In addition, hydrogen sulfide can be immediately dangerous to life and health at concentrations of 100 parts per million. The State of North Carolina, through its 15A NCAC 13B .0544(d)(1), requires owners or operators of all C&D landfills to ensure that the facility: A. Does not exceed 25 percent of the LEL for methane or other explosive gases in facility structures; B. Does not exceed the LEL for methane or other explosive gases at the facility property boundary; and C. Does not release methane gas or other explosive gases in any concentration that can be detected in offsite structures. The LEL means the lowest percent by volume of a mixture of explosive gases in air that will propagate a flame at 25 C and atmospheric pressure per Rule .0544(d)(5). Rule .0544(d)(2) requires that a routine methane monitoring program be implemented to ensure that these standards are met. The type of monitoring will be determined based on soil conditions, hydrogeologic conditions under and surrounding the facility, hydraulic conditions on and surrounding the facility, the location of facility structures and property boundaries, and the location of all off-site structures adjacent to property boundaries. Additionally, frequency of monitoring shall be quarterly. Rule .0544(d)(3) requires that if methane or explosive gas levels exceed the specified limits, the owner or operator must: A) Immediately take all necessary steps to ensure the protection of human health and notify the Division; Section 2 • Regulatory Background 2-2 B) Within seven days of detection, place in the operating record the methane or explosive gas levels detected and a description of the steps taken to protect human health; C) Within 60 days of detection, implement a remediation plan for the methane or explosive gas releases, place a copy of the plan in the operating record, and notify the Division that the plan has been implemented. The plan must describe the nature and extend of the problem and the proposed remedy. As described in Rule 15A NCAC 13B .0554 (f), this Landfill Gas Monitoring Plan is part of the Monitoring Plan for the C&D facility. In addition to the Landfill Gas Monitoring Plan, the Facility Monitoring Plan includes the Water Quality Monitoring Plan. 3-1 Section 3 Gas Control Plan The gas control plan includes a schedule for reading of monitoring LFG emission levels at designated locations quarterly and a system for reporting the concentration levels. The requirements for quarterly monitoring, and the plan for actions if readings exceed safe levels should, at a minimum, be based on compliance with federal and state regulations. This Plan includes monitoring in on-site structures and monitoring wells. 3.1 Frequency of Routine Monitoring Rule .0544(d)(1) and (2) states that a quarterly methane monitoring program be implemented to ensure that the concentration of methane or other explosive gases do not exceed regulatory limits. 3.2 Monitoring Wells Currently, landfill gas monitoring wells MGW-1 through MGW-16 are used to monitor the site. Existing landfill gas monitoring wells, including those associated with future expansions, are provided on Figure 1. One additional landfill gas monitoring well, MGW-17, will be installed as part of the Phase 3 and 4 expansion. The new landfill gas monitoring well will be constructed in accordance with the North Carolina Well Construction Standards described in 15A NCAC 2C and will be completed with a locking above grade protective cover and 2-foot by 2-foot concrete pad. The well will be fitted with a stopcock or quick connect fitting. Following installation, the well will be surveyed to State Plane coordinates. All existing landfill gas monitoring wells were constructed in accordance with the North Carolina Well Construction Standards described in 15A NCAC 2C and were completed with locking above grade protective covers and 2-foot by 2-foot concrete pads. Following installation, the wells were surveyed to State Plane coordinates. The wellhead caps at each LFG monitoring well were fitted with a stopcock type fittings or quick- connects to facilitate sampling in accordance with industry and federal standards. Flooded wells will be replaced with dry wells, if necessary. 3.3 Staffing LFG monitoring requires a trained technician using calibrated equipment that is designed to determine the level of methane or hydrogen sulfide escaping the landfill through monitoring wells and inside structures on the landfill site. Available options include training existing staff, hiring a special contractor, or hiring and training part-time staff to perform this task. 3.4 Monitoring Procedures Each regular quarterly monitoring event should begin by checking methane and hydrogen sulfide levels in the landfill office/scale-house, maintenance buildings, and the recycling convenience Section 3 • Gas Control Plan 3-2 center on the landfill site. Next, the non-occupied buildings at the landfill should be checked. Occupied and unoccupied buildings shall be monitored around the interior of each building. Finally, the landfill gas monitoring wells around the facility should be checked. Landfill gas shall be monitored with a GEM-5000 Plus landfill gas meter or equivalent that is capable of reading percent methane, percent LEL, percent carbon dioxide, and hydrogen sulfide in parts per million. The following monitoring procedures, as described in the Solid Waste Section Guidance Documentation for landfill gas monitoring, shall be followed: The technician using the landfill gas monitoring instrument must understand the principles of operation and follow the manufacturer's instructions. This includes calibrating the instrument according to the manufacturer’s specifications. The following shall be included on the top portion of the landfill gas monitoring form: facility name, permit number, type and serial number of gas monitoring instrument, calibration date of the instrument, date and time of field calibration, type of gas used for field calibration (15/15 or 35/50), expiration date of field calibration gas canister, date of landfill gas monitoring event, name and position of sample collector, pump rate of instrument being used, ambient air temperature, and general weather conditions. Verification that the equipment was calibrated in accordance with the manufacturer’s specifications is required. When determining which field calibration gas to use, take into consideration the expected levels of methane in the landfill gas monitoring wells. If the methane levels are expected to be low, use the 15/15 gas canister (15% CO2/15% CH4). If the methane levels are expected to be high, use the 35/50 gas canister (35% CO2/50% CH4). For every landfill gas monitoring well, verify sample tube purge prior to each sample taken (should be one minute), the time pumped in seconds (should be at least one minute), barometric pressure, time stabilized reading collected, percent lower explosive limit, percent methane by volume, percent oxygen, percent carbon dioxide, and any observations or comments. The landfill gas monitoring data form and results should be retained in the operating record unless an exceedance has occurred and/or is requested by the Solid Waste Section. 3.4.1 Monitoring Times Monitoring times are also important when conducting landfill gas monitoring. Proper landfill gas monitoring should include sampling during times when landfill gas is most likely to migrate. Landfill gas can migrate and accumulate not only in landfill gas monitoring wells; it can also migrate and accumulate in buildings and other structures. Because subsurface gas pressures are considered to be at a maximum during the afternoon hours, monitoring should be conducted in the afternoon or whenever the barometric pressure is low. Scientific evidence also indicates that weather and soil conditions influence the migration of landfill gas. Barometric pressure and precipitation have significant effects on landfill gas migration. Increased barometric pressure generates decreased landfill gas venting from the subsurface, until the pressure within the subsurface is greater than the atmospheric (barometric) Section 3 • Gas Control Plan 3-3 pressure. On the other hand, when the barometric pressure decreases, the landfill will vent the stored gas until a pressure equilibrium is reached. Capping of a landfill can influence the effect of barometric pressure on landfill gas migration. Generally, a more permeable landfill cap will allow greater influence by barometric pressure than a less permeable landfill cap. As a result, landfill gas monitoring should be conducted when the barometric pressure is low and soils are saturated. 3.4.2 Sampling Procedures Any accumulation of landfill gas in the landfill gas monitoring wells may be the result of landfill gas migration. The following procedure is a recommended example for conducting landfill gas monitoring well monitoring, but always read and follow the manufacturer’s instructions because each instrument will be different. 1. Calibrate the instrument according to the manufacturer’s specifications. In addition, prepare the instrument for monitoring by allowing it to properly warm up as directed by the manufacturer. Make sure the static pressure shows a reading of zero on the instrument prior to taking the first sample. 2. Purge sample tube for at least one minute prior to taking reading. Connect the instrument tubing to the landfill gas monitoring well cap fitted with a stopcock valve or quick connect coupling. 3. Open the valve and record the initial reading and then the stabilized reading. A stable reading is one that does not vary more than 0.5 percent by volume on the instrument’s scale. 4. Record the stabilized reading including the oxygen concentration and barometric pressure. A proper reading should have two percent oxygen by volume or less. If levels of oxygen are higher, it may indicate that air is being drawn into the system giving a false reading. 5. Turn the stopcock valve to the off position and disconnect the tubing. 6. Proceed to the next landfill gas monitoring well and repeat Steps 2 – 5. If methane or hydrogen sulfide levels detected at the wells exceed the lower explosive limit, the technician shall immediately follow the action plan presented in Section 4. If the methane or hydrogen sulfide levels detected within on-site buildings are greater than 25 percent of the lower explosive limit, the technician shall immediately follow the actions presented in Section 4 of this report. 3.5 Record Keeping All readings will be recorded on a standard methane monitoring log form. A sample methane monitoring log is provided at the end of this section. These forms will be reviewed and initialed by the landfill supervisor and then placed in the landfill operating records. These quarterly methane monitoring logs will remain on file at the landfill with other landfill records. These readings should be available for review by the State upon request. 16 NC Division of Waste Management - Solid Waste Section Landfill Gas Monitoring Data Form Notice:This form and any information attached to it are "Public Records" as defined in NC General Statute 132-1. As such, these documents are available for inspection and examination by any person upon request (NC General Statute 132-6). Facility Name: ______________________________________________ Permit Number: ____________________________ Date of Sampling: ___________________ NC Landfill Rule (.0500 or .1600): _____________________________________ Name and Position of Sample Collector: _________________________________________ Type and Serial Number of Gas Meter: _______________________________ Calibration Date of Gas Meter: ___________ Date and Time of Field Calibration: _____________________ Type of Field Calibration Gas (15/15 or 35/50): ____________ Expiration Date of Field Calibration Gas Canister: ________ Pump Rate of Gas Meter: _____________ Ambient Air Temperature: __________ Barometric Pressure: ______________ General Weather Conditions: _____________ Instructions: Under “Location or LFG Well” identify the monitoring wells or describe the location for other tests (e.g., inside buildings). A drawing showing the location of test must be attached. Report methane readings in both % LEL and % methane by volume. A reading in percent methane by volume can be converted to % LEL as follows: % methane by volume = % LEL/20 If your facility has more gas monitoring locations than there is room on this form, please attach additional sheets listing the same information as contained on this form. Certification To the best of my knowledge, the information reported and statements made on this data submittal and attachments are true and correct. I am aware that there are significant penalties for making any false statement, representation, or certification including the possibility of a fine and imprisonment. _________________________________________ _________________________________________ SIGNATURE TITLE 4-1 Section 4 Detection Plan Both C&D and the North Carolina Solid Waste Management Rules require a contingency plan for action if methane or explosive gas levels exceed the regulatory concentration limits. The plan for action includes the specific step by step actions needed should regulatory limits be detected. 4.1 Actions if Regulatory Limits Detected in Structures If any structures on the landfill property have detections of methane equal to or greater than 25 percent of the LEL the following actions should be taken: The building should be immediately evacuated; the landfill supervisor should be immediately contacted; all individuals in and around the structure should be ordered to immediately stop smoking; all space heaters and similar appliances should be immediately disconnected from their power source; all doors and windows in the structure which gave the reading should be opened to permit the methane or explosive gas to escape; as a precautionary measure, the landfill operator will open doors and windows in all structures on the landfill property; and equipment used to take the readings should be tested immediately to verify it was giving accurate readings. The technician will then proceed to take readings at all LFG monitoring wells at the landfill. All levels should be verified and recorded on the LFG monitoring log form. This information, including the verification that the equipment is providing accurate readings, the current readings, and the levels at all monitoring locations for the previous three quarters should be provided to the County's landfill supervisor. The Cabarrus County landfill supervisor will make the decision to return to business as usual; temporarily evacuate the site; or follow the plan proposed in Section 4.3. 4.2 Actions if Regulatory Limits Detected at Monitoring Wells If any of the landfill gas monitoring wells measure a level equal to or more than the LEL as defined by in the Rules, the technician should: Immediately contact the landfill supervisor; and recheck the methane levels inside the facility structures. (If levels are close to or exceed 25 percent of the lower explosive level the actions in Section 4.1 should be followed.) Section 4 • Detection Plan 4-2 Once it is verified that levels inside the buildings are safe, the technician should check and record readings at all remaining methane monitoring wells on the site. In addition, the equipment used to take the readings should be tested to verify it is giving accurate readings. This information, the current readings, and the levels for the previous three quarters should be provided to the Cabarrus County landfill supervisor who will make the decision to: return to business as usual; temporarily evacuate the site; or, follow the plan proposed in Section 4.3. 4.3 Compliance Action Plan If upon verification as described in Sections 4.2, the landfill gas monitoring levels are equal to or exceed the regulatory limits as defined by state and federal regulations, the following actions are proposed to comply with state regulations as well as protect the health and safety of the individuals at or near the C&D landfill. 4.3.1 Immediate Action If methane or hydrogen sulfide levels exceed the specified limits, the landfill operator or the landfill supervisor will take immediate action to ensure the protection of human health and safety. This will include: evacuate all buildings on the site; open all doors and windows in buildings on the landfill site; notify the Cabarrus County Manager’s Office about the concentration levels; if warranted by the degree of intensity of the methane or hydrogen sulfide concentration, check the levels in structures near the landfill yet outside the facility boundary; if warranted by the degree of intensity of the methane or hydrogen sulfide concentration, evacuate the landfill area or evacuate the area adjacent to the landfill; notify the State compliance program about the reading; begin to identify or narrow down the source of the methane or hydrogen sulfide causing the readings exceeding the regulatory limits (i.e. the path that the gas is taking to the monitoring location); begin to identify the extent of the LFG problem; and, as appropriate, begin to take corrective action to control the methane or hydrogen sulfide levels in building at the landfill site, at the boundaries to the landfill, and at the landfill site. 4.3.2 Actions Within Seven Days If methane or hydrogen sulfide levels exceed the regulatory limits, in order to comply with the Solid Waste rules, the County must take the following actions within seven days: place in the operating records of the landfill, the gas levels detected; and, Section 4 • Detection Plan 4-3 provide a description to the Solid Waste Section of the steps taken to protect human health. It is also suggested that at this time, the operator begin to develop a plan which: describes the nature and extent of the problem, and proposes the remedy for the problem. 4.3.3 Actions Within Sixty Days If methane or hydrogen sulfide levels exceed the specified limits, the County must take the following actions within 60 days: implement a remediation plan for the gas release; place a copy of the plan in the operating record of the landfill; and notify the appropriate Solid Waste Section official that the plan has been implemented. 4.4 Public Relations and Information As with any potentially dangerous situation, it is important to keep the public, public service agencies, and the media informed. False information, inaccurate information, or the lack of information concerning potential explosions at a public facility could create panic. If the County Manager determines that a potentially dangerous situation exists, it is recommended that a one page explanation of the situation be written and distributed to all homes and businesses within a one-half mile radius of the landfill. This should be done within the first two to four hours of making the determination that a potential danger to human health and safety exists. It is recommended that the County Manager appoint one individual to provide information to; the media; the police authorities with jurisdiction in the area; and area medical facilities. Area hospitals and police departments may receive calls once the local media releases the story. Centralizing the flow of information will avoid conflicting information and inaccurate information. Providing detailed and honest facts about the situation being under control is critical.