Document JrEZyke2rYMnDxzqXBrg4d36O

AR226-2429 CONCEPTUAL CLOSURE PLAN - LETARTLANDFILL SW/NPBES PERMIT APPLICATION NO. WV0076066 (Letter, W. M. Stewart to Dr. L. Eli McCoy, Chief, OWR, 5/26/93) BCC: . B. Allen, Legal, D7156 . Sepulveda, Wilm., D-13098-4 . D. Vandell, Bellevue . L. Riddle, B-12220 E. J. Lutz, DERS I n Di onol HFRfv In Turn: HT"D. Ramsey T. L. Eichstdt M. S. Eaton, Or. W. M. Stewart In Turn: C. F. Muska L. K. Ireland R. S. Hefta File: 33.05.02.05 T. R. Waldron H. D. Bickerstaff R. J. Zipfel G. Woytowich In Turn: --- C 7 1 . Alt E. G. Ramos D. A. Weber D. 0. Harbison N. J. Bittner /hew 8444-4 szmozm EID939403 ) WASHINGTON WORKS P.O. Box 1217 Pa r k e r s b u r g , WV 26102-1217 DU PONT pourMERS CC: Randolph M. Sovic, Branch Leader Industrial Branch WV-DEP, OWR 1201 Greenbrier Street Charleston, WV 25311 David L. Chaney, Geologist Permits Branch WV-DEP, OWR General Delivery McArthur, WV 25873 May 26, 1993 CERTIFIED LETTER RETURN RECEIPT REQUESTED Dr. L. Eli McCoy, 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. WV0076066 Dear Dr. McCoy: This letter summarizes our understanding of the agreements reached in the meeting held on May 6, 1993 regarding the conceptual closure plan tor DuPont's Letart Landfill. Participants in the meeting were: P WV-DEP, OWR 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 permit application for DuPont's Letart Landfill will be submitted to you in July 1993. The closure permit application will conform to the format of the existing operating permit application, and will include the conceptual closure design, a closure schedule, and updated operational and geologic data. The postTdosure 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. RIZO16326 8444-1 ) BETTER THINGS FOR BETTER LIVING EID939404 Dr. L. Eli McCoy -2- May 26, 1993 a The conceptual closure plan (handouts attached), as presented at the May 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 RJZ016327 EID939405 Dr. L. Eli McCoy -3 - May 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". We 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 roe at (304) 863-4271. Very truly yours W. M. Stewart Sr. Environmental Control Consultant Washington Works /hew Attachments 8444-3 RJZ016328 EID939406