7102_PenderCoLF_LFGMonitoringPlan_FID1853497_20240530

LANDFILL GAS MONITORING PLAN
Prepared For:
FORMER PENDER COUNTY LANDFILL
FACILITY NO.: 7102-MSWLF-1984

NEW SAVANNAH ROAD
PENDER COUNTY, NORTH CAROLINA
Prepared By:

Cape Fear Engineering, Inc.
Submitted: May 23, 2024
Table of Contents
Page
1.0 INTRODUCTION ............................................................................................. 1
1.1 Background .......................................................................................... 1
1.2 Site Geology and Hydrogeology ............................................................. 2
1.3 Regulatory Limits .................................................................................. 3
2.0 LANDFILL GAS MONITORING .......................................................................... 3
2.1 Landfill Gas Monitoring Well Locations ................................................... 3
2.2 Landfill Gas Monitoring Well Construction Specifications .......................... 3
2.3 Structure and Ambient Sampling ............................................................ 4
2.4 Landfill Gas Monitoring Frequency .......................................................... 4
3.0 LANDFILL GAS SAMPLING PROCEDURES .......................................................... 4
3.1 Detection Equipment Used .................................................................... 4
3.2 Landfill Gas Sampling Procedure ............................................................ 5
4.0 RECORD KEEPING AND REPORTING ................................................................ 6
4.1 Landfill Gas Monitoring Data Form ......................................................... 6
4.2 Sampling Reports .................................................................................. 6
4.3 Permanent Record Keeping.................................................................... 6
5.0 CONTINGENCY PLAN....................................................................................... 7
6.0 CERTIFICATION OF PROFESSIONAL GEOLOGIST .............................................. 8
List of Figures
Figure 1: Site Vicinity Map
Figure 2: Landfill Gas Monitoring Site Map
Figure 3: Potentiometric Surface Map
Figure 4: Typical Landfill Gas Monitoring Well Schematic
Figure 5: Torquer Vapor Extraction Well Plug
1
FORMER PENDER COUNTY LANDFILL – FACILITY NO. 7102-MSWLF-1984:
LANDFILL GAS MONITORING PLAN
1.0 INTRODUCTION
1.1 Background
The purpose of this Landfill Gas Monitoring Plan (‘Plan’) is to provide a strategy for the
quarterly monitoring of landfill gas at the former Pender County Landfill (Facility No.
7102-MSWLF-1984) located on New Savannah Road in Burgaw, North Carolina (‘Site’)
(Figure 1).
A Plan is necessary to ensure proper performance standards are followed. North
Carolina Solid Waste Management Rules 15A NCAC 13B require quarterly monitoring of
methane gas and quarterly monitoring of methane and other explosive landfill gases
(LFG) to ensure that landfill gas does not exceed the lower explosive limit (LEL) at the
facility property boundary or 25 percent of the LEL in facility structures. If the
concentration exceeds the specified limits, steps must be taken to ensure the
protection of public health and a remediation plan must be implemented immediately.
The Site was used as a municipal solid waste landfill (MSWLF) from 1982 up until 1994.
The extent of the landfill was separated into two phases. Phase I and Phase II, located
in the northern half of the Site, were successfully utilized as trench style landfills with a
soil cap. The area of the subject property that was designated for Phase III of the
landfill was instead used as the current Pender County Animal Shelter (Figure 2).
As part of the post closure requirements required by North Carolina Department of
Environment and Natural Resources (DEHNR) to Pender County in 1995, the
management of landfill gas was listed. There is no evidence that landfill gas monitoring
has occurred at the Site. Additionally, there has not been any provided documentation
that landfill gas monitoring has taken place at the Site after it was closed. Gas
monitoring is required in near-surface soils at designated locations around the
perimeter of the former landfill. Monitoring inside the buildings is required as well.
Subsurface gas typically migrates above the groundwater table and is restricted
2
laterally by streams. Long Creek borders the Site to the west and south; therefore, it is
unlikely gas will migrate off-site in these directions.
1.2 Site Geology and Hydrogeology
According to the Geologic Map of North Carolina (USGS, 1985), the geology of the Site
consists of the Cretaceous Peedee Formation. This formation consists of greenish gray
to olive black sand, clayey sand, and clay. In the upper Peedee Formation, there are
patches of sandy molluscan-mold limestone. The elevation of the Site slopes
downwards from east to west, approximately 50 feet above mean sea level (msl) to
approximately 25 feet above msl.
A subsurface investigation occurred at the Site in 1982 where four soil borings were
advanced, and one piezometer and three monitoring wells were installed. The borings
were drilled to varying depths from 21.5 to 31.5 feet below ground surface (bgs). The
subsurface conditions were described as a 15-foot thick upper zone of clays, silts, silty
sands, and clayey sands which are underlain by clean sands. The uppermost aquifer
was characterized as dark gray silty fine to medium sand. Groundwater levels ranged
from 6.2 to 19.1 feet bgs.
By 1995 when the landfill was closed, there were four groundwater monitoring wells at
the Site and have been monitored semi-annually, as described as post-closure
conditions by DEHNR in 1995. The most recent groundwater elevations measured at the
Site varied from 7.8 to 25 feet bgs. It appears that groundwater flow direction is
correlated with surface topography and generally flows toward the west-southwest
toward Long Creek. A potentiometric surface map illustrating groundwater elevation
and flow direction at the Site is shown in Figure 3.
3
1.3 Regulatory Limits

This Plan is in accordance with North Carolina Solid Waste Management Rules 15 NCAC
13B.1626 and will require quarterly readings. Pender County will follow all requirements
for MSWLF facilities and ensure that:
• The concentration of methane gas generated by the facility does not exceed 25
percent of the LEL for methane in facility structures; and
• The concentration of methane gas does not exceed the LEL (100% LEL or 5% by
volume) for methane at the facility property boundary.

2.0 LANDFILL GAS MONITORING
2.1 Landfill Gas Monitoring Well Locations

The proposed landfill gas monitoring wells for the former Pender County Landfill are
shown in Figure 2. Locations were based on the ability to adequately monitor the
potential for off-site landfill gas migration, site accessibility and the relationship
between the former landfill boundary and on-site/off-site structures. The proposed gas
monitoring well locations were selected with approximately 500 foot spacing. Since gas
migration is restricted laterally by surface water, it will not be necessary to install gas
monitoring wells along the southern and western boundaries of the former landfill. The
only proposed well location along the southern boundary will be installed between the
former landfill boundary and the Pender County Animal Shelter.

2.2 Landfill Gas Monitoring Well Construction Specifications

Details of the proposed landfill gas monitoring well construction are shown on a typical
detail included in Figure 4. The depths of each landfill gas monitoring well will be
specific depending on depth of groundwater and will be installed just above
groundwater levels in the unsaturated zone. The proposed landfill gas monitoring wells
will be constructed in accordance with 15A NCAC Subchapter 2C. Wells will be screened
with 2-inch PVC 10-slot screen from the total well depth between 5 and 10 feet bgs.
4
Well casings will also be comprised of 2” Schedule 40 PVC and capped with quick
connect fitting (Figure 5). A North Carolina Licensed Professional Geologist will be on-
site to supervise the well installation.

Each landfill gas monitoring well will be surveyed for location and elevation by a North
Carolina Registered Land Surveyor. Within thirty days of the completed construction of
each new landfill gas monitoring well, the well construction record (Form GW-1b), a
scaled topographic map of the locations of the new wells, and the boring log/well detail
diagram of each well will be submitted to the Solid Waste Section.

2.3 Structure and Ambient Sampling

For the health and safety for those working at the Pender County Animal Shelter, the
only closed on-site structure, quarterly monitoring will take place in accordance with the
North Carolina Department of Environmental Quality (NCDEQ) Landfill Gas Guidance
Document. It will be ensured that the concentration of methane gas does not exceed
25 percent of the LEL for methane. The location of the Pender County Animal Shelter
can be found in Figure 2.

2.4 Landfill Gas Monitoring Frequency

Landfill gas monitoring will be conducted on a quarterly basis for all on-site monitoring
wells and on-site structures in accordance with Rule 15A NCAC 13B. Monitoring will
continue quarterly for one calendar year, at which time it will be determined by NCDEQ
if continued monitoring is necessary for the Site, based on monitoring results.

3.0 LANDFILL GAS SAMPLING PROCEDURES
3.1 Detection Equipment Used

Gas monitoring at the former Pender County Landfill will be performed on a quarterly
5
basis using a gas analyzer and extraction monitoring instrument, such as a QED
GEM5000, or equivalent meter. Readings will be collected by a trained technician under
supervision of a North Carolina Licensed Professional Geologist. The environmental
consulting firm used should provide calibration records for the equipment used during
monitoring. A copy of the calibration records will be provided with the quarterly gas
monitoring report. In addition to the factory calibration, field calibration of the
instrument should occur as well. Field calibration is performed within a controlled
environment and is initiated by zeroing the instrument using a zero calibration gas. A
span calibration may be necessary, and it is recommended to use a calibration mixture
close to the levels you are trying to measure and should be completed per
manufacturers specifications. The methane levels at the Site are expected to be low,
therefore, a 15/15 gas canister (15% CO2/15%CH4) will be used.

3.2 Landfill Gas Sampling Procedure

Gas monitoring will occur when landfill gas is most likely to migrate. Because
subsurface gas pressures are considered to be maximum during the afternoon hours,
monitoring will be conducted in the afternoon or whenever barometric pressure is low.
The following procedure will be used to complete landfill gas monitoring at the Site:
• Calibrate the gas monitoring instrument according to the manufacturer’s
specifications.
• Allow the instrument to properly warm up and make sure the static pressure
shows a zero reading prior to taking the first sample.
• Purge sample tube for at least one minute prior to taking the reading. Connect
the instrument tube to the landfill gas monitoring well cap fitted with proper
quick connect plug.
• Open the valve and record the initial reading and then the stabilized reading.
Ensure the reading does not vary more than 0.5 percent volume on the
instrument’s scale.
• Record the stabilized reading including the oxygen concentration and barometric
6
pressure. Oxygen levels should be 2% or lower. If levels are higher, it could be a
result of air being drawn into the system, which would give a false reading.
• Turn the valve to the off position and disconnect the tubing
• Proceed to the next gas monitoring well and repeat steps listed above.

4.0 RECORD KEEPING AND REPORTING
4.1 Landfill Gas Monitoring Data Form
Landfill gas monitoring results will be recorded on a Landfill Gas Monitoring Data Form.
The North Carolina Division of Waste Management – Solid Waste Section Landfill Gas
Monitoring Data Form will be used, and an example is shown in Attachment A.

4.2 Sampling Reports

A Landfill Gas Monitoring Report will be prepared after each quarterly monitoring event,
and in accordance with Rule 15A NCAC 13B. The report will be presented as a letter
report that details the date of monitoring, methods used for sampling, exceptions, and
the results of the monitoring event as recorded on the Landfill Gas Monitoring Data
Form. The reports will be signed, certified, and stamped by a North Carolina
Professional Geologist.

4.3 Permanent Record Keeping

The Landfill Gas Monitoring Data Forms and quarterly Landfill Gas Monitoring Reports
will be retained by Pender County and will be a part of the permanent record for the
landfill. The daily activities performed during the quarterly monitoring events by a
certified firm will be entered into a field logbook. A copy of the field logbook notes will
be maintained in the project file.

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5.0 CONTINGENCY PLAN

A contingency plan will be in place for the Site in the event methane exceeds the
regulatory limits defined in Rule 15A NCAC 13B .1626(4)(a). If limits specified in (4)(a)
are detected, the owner or operator will:
• Immediately take all necessary steps to ensure safety to human health and
notify the Division;
• Within seven days of detection, place in the operating record the methane gas
levels and a description of the steps taken to protect human health; and
• Within 60 days of a detection, implement a remediation plan for the methane
gas releases, place a copy of the plan in the operating record, and notify the
Division that the plan has been implemented. The plan will describe the nature
and extent of the problem and the proposed remedy.
If explosive gases are detected above 25% of the LEL within a structure, the building
must be evacuated immediately. The structure should only be re-entered after it is
determined that explosive gas levels are below allowable standards.

FIGURES

SITE VICINITY
3280 NEW SAVANNAH ROAD
BURGAW, NC
VICINITY MAP
NOT TO SCALE
LEGEND
NOTES
DATE: 5/15/2024
SCALE: NOT TO SCALE
DRAWN: LMH
APPROVED: PAD
PREPARED FOR:
PENDER COUNTY
SITE
1. THIS SITE MAP WAS REPRODUCED FROMA GOOGLE AERIAL PHOTOGRAPH.
2. THIS SITE MAP IS NOT TO SCALE.
3. THE PROPERTY BOUNDARIES ARE
APPROXIMATE.
SITE MAP
N.T.S.1
151 Poole Rd. Suite 100 | Leland, NC, 28451TEL [phone] | FAX [phone]www.capefearengineering.com | N.C. LICENSE # C-1621
EX1E405-01
NEW SAVANNAH RD
WILMINGTON ST
PROPERTY BOUNDARY
WETLANDS
LANDFILL GAS MONITORING
SITE MAP
3280 NEW SAVANNAH ROAD
BURGAW, NC
VICINITY MAP
NOT TO SCALE
LEGEND
NOTES
DATE: 4/30/2024
SCALE: NOT TO SCALE
DRAWN: LMH
APPROVED: PAD
PREPARED FOR:
PENDER COUNTY
SITE
1. THIS SITE MAP WAS REPRODUCED FROMA GOOGLE AERIAL PHOTOGRAPH.
2. THIS SITE MAP IS NOT TO SCALE.
3. THE PROPERTY BOUNDARIES ARE
APPROXIMATE.
SITE MAP
N.T.S.1
151 Poole Rd. Suite 100 | Leland, NC, 28451TEL [phone] | FAX [phone]www.capefearengineering.com | N.C. LICENSE # C-1621
EX1E405-01
NEW SAVANNAH RD
WILMINGTON ST
Approximate Extent of
Former Landfill
SW-1
MW-3
MW-2
MW-1
MW-4
MONITORING WELL
SURFACE WATER SAMPLE LOCATION
PROPERTY BOUNDARY
PROPOSED GAS MONITORING
LOCATION
LFG-6
LFG-5
LFG-3
LFG-2
LFG-1
LFG-4
Pender County
Animal Shelter

The Torquer Vapor Extraction plug is a locking monitoring well expansion plug with a
vented port. As a self-sealing watertight cap, it can be used in place of standard monitoring caps for wells where vapor monitoring is required. The locking nylon
expansion plug is a trusted inexpensive watertight locking plug created with integrity. Torquer plugs are reliable, simple to use locking systems with male poppit and dust cap.
• Accepts #1 or #3 type padlocks or Safety Lock-Out Tags.
• High-tech liquid tight seamless rubber gasket.
• Easily disassembled in the field for decon.
• Easy on, easy off wingnut.
• Large, bold, easy to read well ID lettering.
• Bright safety coloring.
• Lightweight, yet super strong.
• Advanced engineered design will not separate in well.
• Easily convertible for vapor extraction, pressure gauges, vacuum gages, and threaded line fittings.
• Domed top prevents liquids from pooling.
• Designed, engineered and manufactured in the U.S.A.

ATTACHMENTS
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) x 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.
SIGNATURE TITLE
Revised – August 23, 2021