4104_HighPointMSWLF_Comment_leachatePondClosure_FID1261521_20181214

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Chao, Ming-tai
From:Chao, Ming-tai
Sent:Friday, December 14, 2018 3:38 PM
To:Pieter Scheer
Cc:Ritter, Christine; Ulishney, Adam; Stanley, Sherri; Aja, Deborah
Subject:Comments on High Point - Kersey Valley MSWLF - Leachate Management System
Modifications
Hi Pieter: I have conducted a review of the permit Modification (FID 1261491) and have several comments on
the project as below:

FID 1261521
Leachate Pond Closure
1. Please provide a detailed soil sampling plan including sampling depth at each location, the sampling
scheme – composite or discrete samples, sampling tools and decontamination procedures, etc., and the
proposed nine (9) soil sample locations should be shown on a drawing.

2. After closing the leachate pond, will the pond be backfilled with clean fill and re-graded/reseeded to
match surrounding grades for facilitating surface drainage? Or the pond will be converted into a
sedimentation basin. Please provide the post-closure land use at this location.

3. (Drawing No. S2) Regarding the sediment/sludge removal from the leachate pond prior to removing the
pond liner, please add the liquid restriction requirement for the sediment / sludge disposal to the Note
3. Prior to disposal, the sludge/sediment must be examined & documented to ensure it either is free of
liquid or passes the test - the SW-846 Test Method 9095B: Paint Filter Liquids Test.

4. 1,4-dioxine exceedance is detected in the monitoring well, MW-9 in 2018 groundwater sampling report
(FID 1261073). Since the well is in the close vicinity of the leachate pond which is receiving leachate
from Phase 3, a potential source of the chemical of concern (COC), to confirm if this COC exists, it is
recommended to test soil samples underneath the leachate pond for 1,4-dioxine, in addition to the
components in the Appendix I.

Phase 3 Sump Improvement
5. The proposal states that “the Phase 3 sump is not operating by gravity as intended and the connection to
the gravity pipe leading away from the landfill is believed to be clogged.” For the clarity, please
mark/note this clogged pipe on the drawing.

6. The approved Closure and Post Closure Plan (DIN 21805) stated that leachate flow rate in closed Area 1
unit is about 100 gallons/acre/day. The new proposed flow rate at Phase 3 sump is 50 gallons/acre/day,
which is a half of the originally estimated amount. Is this new proposed flow rate based on any
historical leachate record or just an engineer judgement?

7. The proposed force main must pass hydro-static pressured test. Please add the test
specification/criterium to the proposal.

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8. The referenced survey drawing – Kersey Valley Landfill Storm Drainage, Leachate Main& Sanitary
Sewer dated October 25, 2016 can’t be located in the SWS file system. Please provide a copy for our
record.

9. The proposal should also address the following health & safety matters, such as OSHA trench safety &
confined space entry, and potential methane exposure including fire result from a spark, and interference
the existing LFGCCS operation, etc.

Please contact me if you have any question on the comments. Thanks.

From: Pieter Scheer [mailto:[e-mail]]
Sent: Thursday, December 13, 2018 5:57 PM
To: Chao, Ming-tai <[e-mail]>
Cc: Stone, Robby <[e-mail]>; Spencer, Mike <[e-mail]>; Smyth, Joan
<[e-mail]>; Scheer, Pieter <[e-mail]>
Subject: [External] High Point - Kersey Valley MSWLF - Leachate Management System Modifications

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Ming:

Please find attached a letter and referenced drawings describing two planned leachate management system
modifications (pond removal and addition of small pump for Phase 3) at the City of High Point’s Kersey Valley MSW
Landfill. Just let me know if you have any questions or comments.

Thanks.

Pieter

Pieter K. Scheer, P.E.
Vice President, Senior Engineer

SMITH + GARDNER

14 N. Boylan Avenue
Raleigh, NC 27603

P [phone]
F [phone]
C [phone]
www.smithgardnerinc.com
Ming-Tai, Chao
Environmental Engineer, Solid Waste Section
Division of Waste Management
North Carolina Department of Environmental Quality
919.707-8251 (Office)
[e-mail]
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