6301_Moore_MSWLF_LFGRemediationPlanAdd_FID1386729_20191220

G GOLDER
December 20, 2019
Jaclynne Drummond
Hydrogeologist, Solid Waste Section
Division of Waste Management
North Carolina Department of Environmental Quality
2090 US Highway 70
Swannanoa, NC 28778
[e-mail]
LANDFILL GAS REMEDIATION PLAN ADDENDUM
MOORE COUNTY LANDFILL, NC SOLID WASTE PERMIT NO. (NC SWP# 63-01)
ABERDEEN, NORTH CAROLINA
Dear Jackie,
Project No. 19127453
In accordance with the approved Landfill Gas Remediation Plan for the Moore County Landfill (NC SWP# 63-01),
Golder Associates NC, Inc. (Golder) is submitting this Landfill Gas Remediation Plan Addendum on behalf of
Moore County, NC (the County). The Landfill Gas Remediation Plan was submitted to NC DEQ on January 31,
2018 and was subsequently approved in a letter dated February 13, 2018.
As you are aware, the County installed a landfill gas cut-off trench in November 2018 per the approved Plan to
address concentrations of methane above the lower explosive limit (LEL) at compliance monitoring point MW-15,
which is located close to the northern property boundary. Following the installation of the trench, Golder
conducted two consecutive landfill gas monitoring events for MW-15 during which methane concentrations were
below the LEL (first and second quarters of 2019). During the third and fourth quarterly methane monitoring
events of 2019, as water levels dropped below the depth of the cut-off trench, methane concentrations were
above the LEL at MW-15.
The results for methane at MW-15 for recent sampling events are as follows:
■ November 28, 2018:
■ February 13, 2019
■ April 3, 2019:
■ September 26, 2019
■ November 20, 2019:
8.1 % CH4 (by volume)
4.1 % CH4 (by volume)
0.6% CH4 (by volume)
55.5% CH4 (by volume)
18.6% CH4 (by volume)
Golder Associates NC, Inc.
5B Oak Branch Drive, Greensboro, North Carolina, USA 27407
Engineering Lic. No. C-2862/Geology Lic. No. C-399
Golder Associates NC, Inc. is a licensed user of the Golder trademark, and an associated operating entity.
Golder and the G logo are trademarks of Golder Associates Corporation.
T: [phone] F: [phone]
golder.com

Jaclynne Drummond Project No. 19127453
Hydrogeologist, Solid Waste Section December 20, 2019
As presented, the first three (3) quarterly monitoring events following installation of the landfill gas cut-off showed
significant improvements in the methane concentrations at MW-15. Methane has been present at various
concentrations in the two (2) passive gas vents associated with the landfill gas cut-off trench suggesting that the
trench has been effective as a methane remedy in this area.
In response to detections of methane above the LEL at MW-15 and in accordance with the schedule in the
approved Plan, this Landfill Gas Remediation Plan Addendum has been prepared to propose an additional
remedy in the area of MW-15. In accordance with the December 31, 2019, date proposed in the approved Plan,
Golder has evaluated additional potential landfill gas remedies in the area of the compliance monitoring location
MW-15. Based on this evaluation, the County plans to install two (2) solar flare units on the two (2) existing
landfill gas cut-off trench passive gas vents. The solar flare units will induce a slight vacuum on the landfill gas
cut-off trench and encourage additional flow of landfill gas out of the ground in the vicinity of MW-15.
The County is prepared to implement this remedy following the completion of the first quarterly methane
monitoring event and by the close of the first quarter in 2020 (March 31, 2020). Should the first quarterly methane
monitoring results show methane concentrations below the LEL at MW-15, the County will wait to implement this
remedy until methane concentrations above the LEL are measured. The remedy will be implemented within 60
days of another observed LEL exceedance. Upon approval by the NC DEQ, the County will proceed with this
plan. Please contact the undersigned at [phone] with any questions or comments. We appreciate your
assistance with this project.
Sincerely,
Golder Associates NC, Inc.
r
Benjamin S. Draper, PG, PMP Rachel P. Kirkman, PG
Senior Project Geologist Associate and Senior Consultant
BSD/RPK/bsd:
CC: David Lambert, JD, MPA, Solid Waste Manager, Moore County, NC
Randy Gould, PE, Public Works Director, Moore County, NC
gAprojects\moore county\19127453 - moore -env services fy19-20\p300 -general consulting\Ifg remediation plan addendum\63-01_20191220
Ifg remediafion plan addendum.docx
GOLDER