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Home My WebLink About1107_BuncombeCoLandfill_HydroReview_DIN28651_20171204 S t a t e o f N o r t h C a r o l i n a | E n v i r o n m e n t a l Q u a l i t y | W a s t e M a n a g e m e n t 1 6 4 6 M a i l S e r v i c e C e n t e r | 2 1 7 W e s t J o n e s S t r e e t | R a l e i g h , N C 2 7 6 9 9 -1646 9 1 9 7 0 7 8 2 0 0 ROY COOPER Governor MICHAEL S. REGAN Secretary MICHAEL SCOTT Director December 4, 2017 Sent via email – chip.gingles@buncombecounty.org Mr. Chip Gingles Solid Waste Manager 81 Panther Branch Road Asheville, NC 28701 RE: Hydrogeologic and Monitoring Reports Technical Review Buncombe County Landfill Facility Permits 1107-CDLF-1998 and 1107-MSWLF-1996 Buncombe County DIN 28651 Dear Mr. Gingles: The Division of Waste Management, Solid Waste Section (Section) has reviewed the C&D Phase 6 Design Hydrogeologic Report and Monitoring reports for the facility submitted by Bunnell- Lammons Engineering (BLE) on behalf of Buncombe County on October 2, 2017. The submitted documents support a separate permit to construct application (DIN 28480) submitted for review to the Section in September 2017. The Design Hydro report addresses regulatory requirements for a proposed 11.9-acre Phase 6 expansion of the existing active construction and demolition landfill. The proposed Water Quality and Landfill Gas monitoring plans combine the monitoring requirements for both the CDLF and the MSW landfill into two separate facility-wide monitoring plans, respectively. Design Hydrogeologic Report – ref 15A NCAC 13B .0538 Upon our review, we have determined that the Design Hydrogeologic Report for Phase 6 C&D expansion meets the criteria required in .0538(b)(1) & (2), including top-of-bedrock datum and seasonal high groundwater table determinations for vertical separation requirements for construction. The Design Hydrogeologic Report (DIN 28512) is approved. Page 2 Water Quality Monitoring Plan – ref 15A NCAC 13B .1623(b)(3); .0544(b) and (c); and .1626(12)(c) There are currently separate water quality monitoring plans approved the facility’s CDLF and MSW landfill: WQ Plan for CDLF (Appendix A of DIN 28279) and WQ plan for MSW (Appendix 5 of DIN 13037). Together, the groundwater monitoring networks are designed to monitor for potential releases from these landfills to the uppermost saprolite/PWR and bedrock aquifers at the site. BLE has proposed to combine and replace these two water quality monitoring plans into a single facility- wide plan. The current groundwater monitoring well network for the CDLF consists of six (6) compliance monitoring wells. BLE has proposed the addition of two compliance wells (MW-17/MW-17D) and one surface water sample location (SW-7) for the planned CDLF Phase 6 expansion. The approved monitoring well network for MSW landfill consists of 19 compliance wells, including two wells (MW-16/MW-16D) to be installed in conjunction with construction of Cell 7. Two facility background wells (MW-1 & MW1D) serve as background wells for both units. Additionally, surface water samples are collected at six (6) locations to monitor surface water surrounding the landfills. For the MSW landfill, eight (8) leachate sample locations have been established for early leak detection and leachate sampling. Water quality and leachate sample collection is performed semi- annually and reported to the Section in accordance with the approved plans. In addition to combining the CDLF and MSW landfill monitoring plans, BLE proposes the addition of two (2) compliance monitoring wells and one surface water sample point for the proposed CDLF Phase 6 expansion. Prior to approval of the proposed WQ plan, please address the following items: • Tetrahydrofuran – in Table 2, add tetrahydrofuran analysis for the CDLF wells (see attached June 2010 memo). • Section 3.1.7.1 Sampling Frequency – if not stated elsewhere, clarify that turbidity field measurements are documented during sampling. • Section 3.1.7.2 Baseline – replace ‘Background’ with ‘Baseline’ in this section. The primary intent of these samples is to establish a baseline for the newly installed compliance wells and new waste areas. Data may or may not be appropriate as site background. Existing wells MW-1 and MW-1D serve as background wells for the facility and a new set of baseline sampling would not be required for these wells. Specific baseline sampling requirements will also be contained in the pending Permit to Construct. • Section 3.3.1 Leachate – Sampling Locations – A leak detection location LD-7 has been previously approved for the planned yet to be constructed Cell 7. Include LD-7 in the list and show approximate location on Figure 2. Leachate monitoring requirements will also be contained as a permit condition in the pending PTC/PTO. Page 3 • Section 3.3.1 Leachate – Monitoring Parameters – Leachate monitoring requirements will be contained as a permit condition in the pending PTC/PTO. Currently, untreated leachate monitoring includes all Appendix I, pH, specific conductance, BOD, COD, nitrates, sulfates, and phosphates. The pond is considered untreated leachate and analyzed accordingly (see current permit DIN 27395 Attachment 3, Part I, #14). The remaining leachate detection locations are analyzed for Appendix I suite, including metals. Please revise the required sampling matrix for the leachate pond in Table 2. • Appendix C – Include the attached September 2016 and June 2010 memos. Landfill Gas Monitoring Plan – ref 15A NCAC 13B .1626(4) and .0544(d) As with the facility water quality monitoring, there are currently separate LFG monitoring plans approved the facility’s CDLF and MSW landfill. In both, the LFG monitoring network is designed to monitor LFG concentrations at the facility boundaries and within onsite facility structures. BLE has proposed to combine and replace these two plans in a single facility-wide LFG monitoring plan. The existing LFG monitoring network includes two (2) LFG monitoring wells for CDLF and four (4) LFG wells for the MSW landfill (an additional five (5) future LFG monitoring wells have been approved, but not installed, for planned expansion of the MSW landfill). Additionally, gas monitoring of nine (9) landfill facility structures is conducted. To address the Phase 6 CDLF expansion, one (1) additional LFG monitoring well M-12 is proposed. Prior to final approval of the proposed LFG plan, please address the following items: • Section 3.8.2 – Add H2S reporting limits (see monitoring form) • Table 1 – coordinates for some locations are “UK”, but locations are shown on the map. If locations on the site map are approximate, but exact coordinates not available, revise table to reflect that. If you have any questions or need further assistance on this review, please contact me via email at perry.sugg@ncdenr.gov or by phone at (919) 707.8258. Sincerely, Perry Sugg, PG Permitting Hydrogeologist Solid Waste Section Cc: Ed Mussler, PE - SWS Permitting Branch Head Allen Gaither, PE – SWS Permitting Engineer Andy Alexander, PG - BLE Inc.