3402_HanesMill_LFGMonitoringPlan_DIN28003_20170707

Landfill Gas
Monitoring Plan
Hanes Mill Road Landfill
Winston-Salem City/County Utilities

Winston-Salem, North Carolina
July 2017

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Contents
Contents
1.0 Introduction ........................................................................................................................ 3
2.0 Background Information ..................................................................................................... 3
2.1 General ........................................................................................................................... 3
2.2 Site Information .............................................................................................................. 3
3.0 Landfill Gas Overview & Regulatory Action Levels ............................................................ 3
4.0 Landfill Gas Monitoring ...................................................................................................... 5
4.1 Proposed Landfill Gas Monitoring Procedure ................................................................. 5
4.1.1 Permanent Monitoring Station Design and Installation ........................................... 5
4.1.2 Gas Migration Monitoring ...................................................................................... 10
4.1.3 Reporting of Data and Record Keeping ................................................................ 13
4.1.4 Continuous Monitoring of On-Site Structures ........................................................ 13
4.2 Schedule for Installation of Monitoring Elements ......................................................... 13
4.3 Maintenance and Calibration of Monitoring Elements .................................................. 13
4.3.1 Maintenance of Permanent Monitoring Stations ................................................... 13
4.3.2 Calibration of Portable Monitoring Instruments ..................................................... 14
5.0 Contingency Plan ............................................................................................................. 14
5.1 Contingency Plan Guidelines ....................................................................................... 14
5.2 Contingency Plan - On-site Structures ......................................................................... 15
5.2.1 Immediate Action ................................................................................................... 15
5.2.2 Action within 7 Days .............................................................................................. 15
5.2.3 Action within 60 Days ............................................................................................ 15
5.3 Contingency Plan - Facility Property Boundary ............................................................ 15
5.3.1 Immediate Action ................................................................................................... 16
5.3.2 Action within 7 Days .............................................................................................. 16
5.3.3 Action within 60 Days ............................................................................................ 16
6.0 LFG Control System Installation and Monitoring .............................................................. 17
6.1 Passive Gas Control System ........................................................................................ 18
6.1.1 Surface Monitoring and Observations ................................................................... 18
6.1.2 Subsurface Pressure ............................................................................................. 18
6.1.3 Proximity ................................................................................................................ 18
6.2 Active Gas Control System ........................................................................................... 18
6.2.1 Gas Collection System .......................................................................................... 18
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Contents
6.2.2 Gas Utilization or Control System ......................................................................... 19
7.0 Safety ............................................................................................................................... 19

Tables
Table 1 Compliance Levels for Methane ...................................................................................... 4
Table 2 Expansion Landfill Site Existing Methane Wells – Phase 1 ............................................. 5
Table 4 Contingency Plan Contacts ............................................................................................ 15

Figures
Figure 1 Gas Monitoring Wells (00G-03) ...................................................................................... 7
Figure 2 Gas Monitoring Wells (00G-04) ...................................................................................... 8
Figure 3 Typical Methane Probe Construction .............................................................................. 9
Figure 4 Groundwater Surface Contour Map .............................................................................. 11

Appendices
Appendix 1 - Field Data Form
Appendix 2 – Boring Logs

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Introduction
1.0 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.
2.0 Background Information
2.1 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.
2.2 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. Land to the south
is being used for other commercial endeavors, as well as residential development.
3.0 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),
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Landfill Gas Overview & Regulatory Action Levels
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%

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Landfill Gas Monitoring
4.0 Landfill Gas Monitoring
4.1 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 3 expansion area as needed.
4.1.1 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. Figures 1 and 2, Gas Monitoring Wells (Drawings 00G-03
and 00G-04) show the monitoring wells at the landfill.
4.1.1.1 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 Drawings
00G-03 and 00G-04). Four additional wells have been installed for Phase 2 (MM-9 through MM-
12). 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 3 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 37 Feet 5-37 Feet
Notes: (1) See boring logs for subsurface lithology (Appendix 2)
(2) See potentiometric surface map for depth to groundwater

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Figure 3 Typical Methane Probe Construction
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Winston-Salem City/County Utilities 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. Since installation wells MM-1
and MM-2 have been retired. Refer to Figure 4, Groundwater Surface Contour Map, for the
depth to groundwater.
4.1.1.2 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. Since installation wells MM-H, MM-I, MM-J, MM-P through MM-T, MM-U, and
MM-Z have been retired.
4.1.1.3 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.
4.1.2 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.

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Landfill Gas Monitoring
Information from the monitoring will be recorded on the field data form (Appendix 1). Any
readings recorded at or above the LEL for methane will be immediately verified and reported as
described in the Contingency Section of this plan.
4.1.3 Reporting of Data and Record Keeping
All monitoring data acquired in the field will be recorded on the field data form (refer to Appendix
1). 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.
4.1.4 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 the Contingency Section of this LGMP.
4.2 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.
4.3 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.
4.3.1 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.
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Contingency Plan
• 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.
4.3.2 Calibration of Portable Monitoring Instruments
4.3.2.1 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.
4.3.2.2 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.
5.0 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 Table 1 – Compliance Levels of
Methane in this plan).
5.1 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.
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Contingency Plan
Table 3 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

5.2 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.
5.2.1 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 Table 3 Contingency Plan Contacts will be contacted.
• Notify NCDEQ.
• 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.
5.2.2 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 Immediate Action section of this LGMP.
5.2.3 Action within 60 Days
5.2.3.1 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).
5.2.3.2 IMPLEMENTATION OF THE PLAN
NCDEQ will be notified that the Plan has been implemented.
5.3 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.
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Contingency Plan
5.3.1 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 Table 4 Contingency Plan Contacts of this plan,
may be contacted.
• Notify NCDEQ.
5.3.2 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 Immediate Action section of this LGMP.
5.3.3 Action within 60 Days
5.3.3.1 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.
5.3.3.2 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 the Contingency Plan section, 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 1).
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
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
LFG Control System Installation and Monitoring
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 1. 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 the Contingency
Plan section of this LGMP.
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.
5.3.3.3 IMPLEMENTATION OF THE PLAN
NCDEQ will be notified that the remediation plan has been implemented.
6.0 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 Landfill Gas Monitoring section 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.
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
LFG Control System Installation and Monitoring
6.1 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 the Active
Gas Control System Section).
The locations of the passive vents are determined using any one, or a combination, of the
following three methods.
6.1.1 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.
6.1.2 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.
6.1.3 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.
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 Landfill Gas
Monitoring section of this Plan.
6.2 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.
6.2.1 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
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Safety
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.
6.2.2 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.
7.0 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.
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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Safety
• 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.

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Appendix 1 - Field Data Form

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Appendix 1 - Field Data Form

Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Appendix 1 - Field Data Form

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Revised – March 6, 2017
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:
Sampling Date: NC Landfill Rule (.0500 or .1600):

Sample Collector Name & Position:

Gas Meter Type & Serial Number: Gas Meter Calibration Date:

Field Calibration Date & Time:

Field Calibration Gas Type (15/15 or 35/50): Field Calibration Gas Canister Expiration Date:

Gas Meter Pump Rate:

Ambient Air Temperature: Barometric Pressure (in. or mm Hg): Weather Conditions:

Instructions: Under “Location or LFG Well”, list monitoring well # or describe monitoring location (e.g., inside field office).
Attach a test location map or drawing. Report methane readings as both % LEL and % CH4 by volume.
Convert % CH4 (by volume) to % LEL as follows: % methane (by volume)/20 = % LEL.
*Hydrogen Sulfide (H2S) gas monitoring may be required for Construction & Demolition Landfills (CDLFs). See
individual permit conditions and/or Facility LFG monitoring plan.

Location or
LFG Well ID
Sample
Tube
Purge

Time of
Day
Time
Pumped
(sec)
Initial
% LEL
Stabilized
% LEL
% CH4
(volume)

% O2
(volume)

% CO2
(volume)

% H2S*
(volume)

NOTES

NOTE: If needed, attach additional data forms to include additional LFG monitoring data locations for the facility.

ACTION LEVELS: Methane: >1.25% by volume (inside structures) AND >5% by volume (at facility boundary)
Hydrogen Sulfide: >1% by volume (inside structures) AND >4% by volume (at facility boundary)

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.

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Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Appendix 2 – Boring Logs

2
Appendix 2 – Boring Logs

Winston-Salem City/County Utilities Commission | Hanes Mill Road Landfill – Landfill Gas Monitoring Plan
Appendix 2 – Boring Logs

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HDR Engineering, Inc. of the Carolinas
440 S Church Street, Suite 1000
Charlotte, NC 28202-2075
704.338.6700
NC License F-0116
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