6013_Mecklenburg_NorthMeck_GreenwayWaste_CDLF_LFGMigrationPlan_FID1891408_20240802

GreenuiacP. ulusto Solutions
Sent Via E-mail to
i aclynne.drummond(&ncdenr.2ov
August 2, 2024
NC Department of Environmental Quality
Solid Waste Section
217 W Jones Street
Raleigh, NC 27603
Attn: Ms. Jaclynne Drummond,
Re: Landfill Gas Migration Corrective Action
Greenway Waste Solutions at North Meck, LLC
Huntersville, North Carolina
Solid Waste Facility Permit Number 60-13
Dear Ms. Drummond:
In accordance with your email response to the results of the 2024 Q2 Methane Monitoring Reports
for the Greenway Waste Solutions at North Meck, dated June 20, 2024, Greenway Waste Solutions
at North Meck, LLC (GWSNM) is pleased to provide this corrective action plan to address landfill
gas detections in methane monitoring well MMW-3 as well as assessment gas probes GP-1 and GP-
2.
Proposed Corrective Action
GWSNM proposes to install a passive gas collection trench between the waste footprint limits and
methane monitoring well MMW-3 and gas probes GP-1 and GP-2. A map depicting the proposed
location of this trench relative to MMW-3, GP-1, and GP-2 is provided as Figure 1. The trench will
be installed at a depth of approximately 15 feet below ground surface to match the total depth of
MMW-3, GP-1, and GP-2. A perforated horizontal pipe enveloped in coarse aggregate will collect
soil gas, which will be ventilated through vertical risers fitted with passive turbines commonly
referred to as "whirlybirds". A detail schematic of the proposed gas collection trench is provided as
Figure 2.

Ms. Jaclynne Drummond
August 2, 2024
Page 2
Proposed Ongoing Monitoring
GWSNM proposes to continue monthly monitoring of MMW-3 as well as GP-1 and GP-2. In
addition, monthly monitoring will be conducted on the gas collection trench ventilation risers.
GWSNM will provide an updated Landfill Gas Monitoring Plan for the landfill facility upon
approval of this plan.
Potential Future Actions
Monitoring data will be assessed for efficacy following one year of monthly monitoring following
trench installation. If the monitoring data indicates a decreasing trend in landfill gas concentrations,
the trench will be left in place and monthly monitoring will continue until detections of methane fall
below 5% by volume, at which point GWSNM may propose to reduce the monitoring frequency to
quarterly. In the event that concentrations of landfill gas in MMW-3, GP-1, and GP-2 remain stable
or increase, GWSNM will connect the trench to the existing active landfill gas extraction system.
As mentioned above, GWSNM will provide an updated Landfill Gas Monitoring Plan upon the
approval of this proposed corrective action. GWSNM will submit a report documenting the final
installation details of the trench upon completion of construction activities. Should you have any
questions or require any additional information, please feel free to contact me at [phone] or
[e-mail].
Sincerely,
Brandt Kayser, P.G.
Environmental Compliance Officer
Attachments:
Figure 1 — Proposed Passive Gas Collection Trench Plan
Figure 2 — Proposed Passive Gas Collection Trench - Detail
B Griffin Brothers Co.
Greenui lUaste Solutions

Zk
LEGEND
--- --- PROPERTY LINE
8 MMW-1 INFILL AREA
METHANE MONITORING WELL
LANDFILL POINT OF
® MW-4A COMPLIANCE GROUNDWATER
MONITORING WELL
(D GP-1 GAS PROBE
REFERENCE
PROPOSED GAS
TRENCH LOCATION
(- 177LF)
SCALE IN FEET
0 100 200
IGP-1
'' GP-2
MW-160)
MW-2(i)
1. AERIAL IMAGERY BY CIVIL & ENVIRONMENTAL CONSULTANTS,
DATED JUNE 4, 2024.

200' MAXIMUM VENT PIPE SPACING
V� PASSIVE GAS COLLECTION TRENCH DETAIL
N.T.S.
♦IA ALL HOLES
6" (TYP.) 1/2" 0 \
900 \
Al TYP.
,+JA 6"0 HDPE
DSECTION A -A
R-11 PIPE
PERFORATION PATTERN
2 HDPE PIPE PERFORATIONS
2 N.T.S.
6" STAINLESS TURBINE
VENTILATOR (TYP.)
u
DR-11
F
_RFORATED
PE (TYP.)
NON -WOVEN FILTER
FABRIC TO BE PLACED
BETWEEN AGGREGATE
AND SOIL BACKFILL
6" HDPE DR-11 NON -
PERFORATED 90 DEGREE
ELBOWS (TYP.)
6" HDPE DR-11
PERFORATED EXTRACTION
PIPE (SEE DETAIL 2)
NCDOT NO. 4A
COARSE AGGREGATE
NONCALCEROUS STONE
ONLY (NO FINES)
TERMINATE P
OR ROCK, 0« vrviv r«rwnnvv
DEPTH LIMIT OF 20 FEET
A SECTION
2 N.T.S.
SOIL BACKFILL
NON -WOVEN 6 OZ/SY
GEOTEXTILE TO BE
PLACED BETWEEN
AGGREGATE AND SOIL
BACKFILL
6" HDPE PERFORATED
PIPE (SEE DETAIL 2)
VCDOT NO. 4A
-OARSE AGGREGATE
VONCALCEROUS STONE
DNLY (NO FINES)