0603_AveryCDLF_HydroReview_DIN25929_21060408.pdf

PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary

MICHAEL SCOTT
Acting Director

April 8, 2016

Ms, Madeline German, P.G.
Smith Gardner, Inc.
14 N. Boylan Avenue
Raleigh, NC 27603

Re: Permit Renewal (0603-CDLF))
Avery County CDLF - Avery County NC
Hydrogeology Review DIN 25929

Dear Ms. German,
I have reviewed the permit renewal application (DIN 25749) submitted for the referenced facility in regards
to hydrogeological considerations (per 15A NCAC 13B .0544), specifically as contained in the permit
renewal application: Attachment C – Water Quality Monitoring Plan (WQ Plan) and Attachment D Landfill Gas
Monitoring Plan (LFG Plan). Pertinent components of the proposed Operations Plan (Attachment C) were also
reviewed for consistency. The application was received by the Solid Waste Section (Section) on March 14,
2016 from Smith Gardner Engineers on behalf of Avery County. According to the permit application
submittal, Avery County is requesting an amendment to the operations permit for continuing operations
through the next five-year permitting cycle.

The most recent Design Hydrogeologic Report for a landfill expansion was approved in 2010 (DIN 10060).
Since the current request is for continued operation of approved activities, no additional geologic or
hydrogeologic investigations (per 15A NCAC 13B .0538) are warranted at this time.

Water Quality and Landfill Gas Monitoring Plans
The Avery County CDLF facility is currently operating under water quality and landfill gas monitoring plans
and operation manual (DIN 6894 and DIN 11333) approved by the Section in 2009 and 2010 as part of the
permit-to-operate (DIN 13546) issued in 2011 for the landfill expansion. The approved documents included
the current groundwater, surface water, and landfill gas monitoring network as it exists today: four (4)
detection monitoring wells, two surface water monitoring locations, and four (4) LFG monitoring probes.
This existing monitoring network is adequate for continual subsurface environmental monitoring at the
facility. The monitoring plans are designed to detect early release of constituents to the uppermost aquifer
and dangerous levels of explosive gases. Water sample collection is performed semiannually and reported to
the Section. LFG measurements are taken quarterly and reported if exceedances are found.

In the current permit renewal application submitted by Smith Gardner, the facility Water Quality Monitoring
Plan and the LFG Monitoring Plan remain basically unchanged with only minor updates.
Page 2

Prior to final approval of these plans, the following revisions are requested:

 WQ Plan Section 2.2.1 Guidance Docs: Add the most recent guidance (November 5, 2014) for
submittal of environmental data. Can be downloaded from our website: SWS Electronic Data
Submittal Memo - Nov2014
 LFG Plan General: Due to the nature of materials disposed in them, C&D landfills are a source of
the explosive gas hydrogen sulfide (H2S). The plan as submitted needs to be amended to also
include hydrogen sulfide gas (H2S) monitoring. Please add H2S monitoring for the following wells
and buildings: GP-1, GP-2, GP3, GP-4 and the Scale house.
 LFG Plan Section 2.3.4 Procedures: add regulatory action limits for hydrogen sulfide (4% by
volume for 100 LEL and 1% by volume for 25% LEL, respectively).
 LFG Plan Section 2.3.3 Equipment: include equipment and/or method for H2S measurements, if
different than what’s listed.
 LFG Plan Section 3 Contingency: add note about how to address H2S readings detected above
regulatory limits as well.
 LFG Monitoring Data Form: include column for H2S measurements for the locations specified
above.

If you have any questions concerning these comments, please do not hesitate to contact me via
email [e-mail] or phone [phone].

Sincerely,
Perry Sugg, PG
Permitting Hydrogeologist
Solid Waste Section

Cc: Stacey Smith PE – Smith Gardner
Allen Gaither – SWS, Permitting Engineer