0601_AveryCounty_MSWLF_LFGWorkPlan_FID1792016_20230427

DocuSign Envelope ID: C6CDD9CC-9B7C-4FB4-9F11-7A3199DB3C6C
SMITH GARDNER
ADDRESS TEL WEB
14 N. Boylan Avenue, Raleigh NC 27603 919.828.0577 www.smithgardnerinc.com
April 27, 2023
Ms. Jaclynne Drummond
NCDEQ DWM Solid Waste Section
1646 Mail Service Center
Raleigh, North Carolina 27699-1646
RE: Landfill Gas Mitigation Work Plan
Avery County Closed MSW Landfill
Spruce Pine, North Carolina
Dear Ms. Drummond:
Smith Gardner, Inc. (S+G) is pleased to provide this response to your email of March 6, 2023
(see attached) regarding continuing methane exceedances at the Avery County Closed MSW
Landfill located near Spruce Pine, North Carolina. This work plan outlines next steps to
evaluate additional remedial responses for landfill gas (LFG) at the site.
Site Background
The site has an active Landfill Gas Collection and Control System (LFGCCS) consisting of 10
Landfill gas extraction wells (W-1 through W-10) (see Figure 11, HDPE piping for transmission
of collected landfill gas, a one (1) horsepower blower, a condensate trap and storage tank, a
candlestick flare, and associated valves and gauges. It should be noted that the blower is
currently not operational, but is being replaced upon procurement of a new blower. Current
Lead time of blowers is delaying replacement.
The site also has a perimeter LFG monitoring network that consists of 13 monitoring probes
(P-1 through P-13) located around the facility, and in some cases, on adjacent properties.
Three of the probes (P-1, P-3, and P-7) have been connected to the LFG system to increase
recovery efforts.
Landfill gas monitoring and LFGCCS maintenance is completed on a monthly basis due to
Landfill gas concentrations detected in monitoring probes off -site. Results of monthly
monitoring indicate three (3) probes (P-1, P-3, and P-7) have exhibited concentrations of
methane above the lower explosive limit (LEL) since at least 2011 (see Figure 2). Probe P-3
was connected to the LFG system in 2014, followed by the connection of P-1 and P-7 to the
system in 2015. The initial connection to the system resulted in decreased methane
concentrations that hovered around the lower explosive limit (LEL). Beginning in 2019, large
spikes in methane concentrations were observed in P-1 and P-3. Since that time all three (3)
probes have consistently had methane concentrations above the LEL. Most recently, increases
in methane concentrations were observed again in P-1 and P-3, prior to the LFG system blower
ceasing to function. Since that time, concentrations of methane recorded in the probe have
decreased, but remain above 50% methane.

DocuSign Envelope ID: C6CDD9CC-9B7C-4FB4-9F11-7A3199DB3C6C
Ms. Drummond
April 27, 2023
Page 2of2
Proposed Work Plan
As can be seen on Figure 1, landfill gas monitoring probes P-1 and P-3 are on the northern
property line, and probe P-7 is located on the western property line. Currently P-1 and P-3
have LFG extraction wells within 200 feet of the probe, whereas P-7 does not.
S+G proposes to install additional LFG extraction wells in the vicinity of these probes. At a
minimum, one (1) new well will be installed in the vicinity of each probe. The exact location,
depth, and quantity of LFG extraction wells will be determined based on historical LFG
monitoring information. Upon completion of the LFG system expansion, a summary report will
be submitted to NCDEQ.
If you have any questions, or require additional information, please contact us at your earliest
convenience at 919-828-0577 or by e-mail (address below).
Sincerely, ,,CiArq,O��i
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Smith Gardner, Inc. ,�,................ 7y,��%,
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Attachments: Figure 1 (Site Map)
Figure 2 (LFG Concentrations Over Time)
NDEQ Exceedance Letter
CC: Eric Foster - Avery County
File
H:\Projects\Avery County (NC)\Avery-21-3 (General Engineering)\LFG Remediation\Work Plan\Letter\Avery Co LFG Remediation
Work Plan Mar 23.docx

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,,. •�;�` REFERENCES
«� -A 1. ADJACENT PROPERTIES ARE FROM AVERY COUNTY GIS MAPPING
DEPARTMENT.
_• r 2. MONITORING WELL LOCATIONS FROM FIELD SURVEY DATED 1/14/08, BY
SURVEYING SOLUTIONS, P.C.
3. PROPERTY LINE FROM FIELD SURVEY DATED APRIL 9, 2010, BY
.1�►.,N APPALACHIAN PROFESSIONAL LAND SURVEYORS & CONSULTANTS.
• 4. LFG PROBES LOCATIONS FROM FIELD SURVEY DATED APRIL 9, 2010, BY
APPALACHIAN PROFESSIONAL LAND SURVEYORS & CONSULTANTS.
�, • • PROBE P-2, P-3, AND P-9 THROUGH P-13 LOCATIONS WERE NOT
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DocuSign Envelope ID: C6CDD9CC-9B7C-4FB4-9F11-7A3199DB3C6C
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DocuSign Envelope ID: C6CDD9CC-9B7C-4FB4-9F11-7A3199DB3C6C
ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
MICHAEL SCOTT
Director
NORTH CAROLINA
Environmental Quality
March 6, 2023
Sent Via Email - [e-mail]
Mr. Eric Foster
Avery County Solid Waste Director
175 Linville Street
Newland, NC 28657
Re: Landfill Gas Exceedances
Avery County MSW Landfill
Avery County
Solid Waste Permit Number 0601-MSWLF-1987
FID 1774038
Dear Mr. Foster,
The Solid Waste Section (Section) has completed a review of the Operations, Monitoring, and
Maintenance Report - February 2023 dated February 28, 2023 (FID 1773669) and submitted
on your behalf by Smith Gardner for the closed unlined Avery County MSW Landfill, Solid Waste
Permit Number 0601-MSWLF-1987. The active landfill gas collection and control system has
been operating at the landfill for about 10 years with modifications occurring over the years. With
this landfill gas system in place, there are still consistent landfill gas exceedances near the
property boundary. Given the right conditions, methane gas has the potential to be a significant
public health hazard, and the dynamics that influence gas movement and migration vary. Avery
County is required to prevent the migration of methane gas at the property boundary in
accordance with 15A NCAC 13B .0503(b)(1).
Based upon these consistent landfill gas exceedances, additional activities are required. Please
submit a work plan for Section review to modify the active landfill gas collection and control system.
If you have any questions or concerns regarding this letter, please feel free to contact me by email
at [e-mail] or by phone at 828.296.4500. Thank you for your
cooperation with this matter.
Sincerely,
;�4— L)--
Jaclynne Drummond
Hydrogeologist
Solid Waste Section, Division of Waste Management
NCDEQ
cc sent via email: Perry Sugg, SW Environmental Compliance Branch Head
D E Q�� Office
Carolina Department of Environmental Quality I Division of Waste Management
Asheville Regional Oce 1 2090 U.S. Highway 70 1 Swannanoa, North Carolina 28778
NORTH CAROLINA
ftp.ro .M W E-i.—l Q.Wny /`� 828.296.4500

DocuSign Envelope ID: C6CDD9CC-9B7C-4FB4-9F11-7A3199DB3C6C
Jason Watkins, SW Field Operations Branch Head
Deb Aja, SW Western District Supervisor
Kris Riddle, SW Environmental Senior Specialist
Sherri Stanley, SW Permitting Branch Head
Joan Smyth, Smith Gardner
E QII�� Office North Carolina Department of Environmental Quality I Division of Waste Management
Asheville Regional Oce 1 2090 U.S. Highway 70 1 Swannanoa, North Carolina 28778
NORTH CAROLINA _
Depamoam or Enmmamamai ausifty /� 828.296.4500