Document vYBx7DZopyaxE50L4j5vLO5Z

AR226-2429 ^f^ ^ CONCEPTUAL CLOSURE PLAN gtf/MPDES PERMIT APPLICAT - I O ^ N ^. HO. ^WWV0 017 610 166 (Letter. W. M. Stewart to Dr. L. Eli McCoy. Chief, OWR. 5/26/93) BCC: J. B. Alien. Legal. D7156 F. Seputveda. Mnin.. D-13098-4 T. D. VanxleTI, Bellevue J. L. Riddle, B"12220 E. J. Lutz, DERS L. D. Riegel, DERS In Turn: H7~D. Ramsey T. L. Eichstadt M. S. Eaton, Jr. W. M. Stewart In Turn: ----CTT. Muska L. K. Ireland R. S. Hefta File: 33.05.02.05 T. R. Waldron H. D. Bickerstaff R. J. ZtpfeT 6. Woytowich In Turn: ----CTT. Alt E. E. Raroos D. A. Weber D. J. Harbison N. J. Bittner /hew 8444-4 EID939403 CT7 REV. KHO CMD WASHINGTON WORKS P.O. Box 1217 PARKERSBURG.WV 26102-1217 DU FONT POt-YMERS CC: Randolph M. Sovic. Branch Leader Industrial Branch MV-DEP. OWR 1201 Greenbrier Street Charleston, MV 25311 David L. Chaney, Geologist Permits Branch WV-DEP. OWR General Delivery HcArthur, MV 25873 May 26, 1993 CERTIFIED LETTER RETURN RECEIPT REQUESTED Dr. L. Eli HcCoy. Chief Office of Water Resources WV Division of Environmental Protection 1201 Greenbrier Street Charleston, West Virginia 25311 RE: Letart Landfill SW/NPDES Permit Application No. WVQ076066 Dear Dr. McCoy: This letter summarizes May 1993 our understanding of the regarding the conceptual agreements reached closure plan for in the meeting held on 6, DuPont's Letart Landfill. Participants in the meeting were: WV-DEP, DWR - R. M. Sovic. Branch Leader, Industrial Branch D. L. Chaney, Geologist, Permits Branch DuPont - W. M. Stewart, Environmental Manager T. D. Vandell, Core Group, Hydrogeolist E. J. Lutz, DERS, Engineer The following is a summary of the discussion: A closure submitted permit to you application for DuPont's Letart Landfill will in July 1993. The closure permit application be will conform to the format of the existing operating permit application, and and will include the conceptual closure design, updated operational and geologic data. The a closure schedule, post-closure ground and surface water monitoring plan will be submitted in 1994, after we have collected enough water quality data to verify the constituents of concern to be monitored for following closure. 8444-1 BETTER THINGS FOR BETTER LIVING EID939404 Dr. L. E!i McCoy - 2 - May 26, 1993 The conceptual closure plan (handouts attached), as presented at the Hay 6, 1993 meeting, addresses the issues included in the West Virginia Solid Waste Management Regulations. Assumptions made for the conceptual design will be verified in order to complete the final detailed design. This will be accomplished by field and laboratory testing. Cap construction details and all detailed design specifications will be based on and supported by this data, in accordance with accepted engineering practices. It was agreed that the closure schedule, as presented at the May 6, 1993 meeting, will be changed to reduce the completion time for the Health and Safety Plan (HASP), and to move forward the start-up time for field activities. The requirement for Administrative Notice is to be deleted. The approach to developing the long-term ground and surface water monitoring program is acceptable to the WV-DEP and includes the following changes to our March 3, 1993 submittal: - There will be at least four quarters of water quality sampling for both surface water and ground water versus two that DuPont proposed in the March 3. 1993 sampling plan. - Second quarter water quality monitoring will be conducted according to our March 3, 1993 submittal, but due to very limited yields from most of the wells, the parameters included for future analyses will be reduced and re-prioritized based on the constituents present. These proposed sampling changes will be submitted to the WV-DEP for approval before the third quarter sampling is carried out. - Because total and dissolved metals concentrations are similar due to the low TSS in the ground water, total metals concentrations are representative of metals concentrations in the ground water at Letart. DuPont agrees to monitor only total metals concentrations in the ground water. - It was agreed that, based on the requirements, there is sufficient coverage of the F-Zone at Letart with the existing monitoring wells (1 upgradient and 3 downgradient). However, DuPont will conduct a field investigation to the northeast of the active portion of the landfill to identify any seeps that could also serve as ground water monitoring points. - Water quality data from the analyses conducted to-date, demonstrate that anaerobic biodegradation is not occurring in the shallow zones at LMWs 1, 4, and 8. Therefore, we will discontinue the additional analytical parameters included for this evaluation. 8444-2 EID939405 ; ' . Dr. L. Eli McCoy - 3 - Hay 26. 1993 Due to the difficulty associated with remediation and reversing existing natural aerobic conditions to anaerobic in low permeability zones, such as those encountered at Letart, the affects of hazardous constituents at Letart will be evaluated using a risk assessment approach. Regulation 4.11.5 of the Solid Waste Management Regulations states that where there is ground water contamination, the Chief may require appropriate corrective or remedial action. and such action "shall take into account any applicable ground water quality protection standards, the existing use of such waters, the reasonable uses of such waters, background water quality, and the protection of human health and the environment". He interpreted this to mean a risk assessment approach could be used in completing this evaluation. The new West Virginia ground water quality regulations will also be reviewed. We appreciated the opportunity to review our plans for closing the Letart Landfill with the members of your staff. If you have any questions or need additional information, please contact me at (304) 863-4271. Very truly yours, 1/^M^^ W. M. Stewart Sr. Environmental Washington Works Control Consultant /hew Attachments 8444-3 S o\ L^l M 00 EID939406