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HomeMy WebLinkAbout6301_Moore_CDLF_AssessmentWorkPlanResponse_DIN28725_20180123 January 23, 2018 Sent Via Email - cbeane@moorecountync.gov Mr. Chad Beane Moore County Solid Waste P.O. Box 1927 Carthage, North Carolina 28327 Re: Assessment Monitoring Plan Unlined Moore County Active C&D Landfill Moore County Solid Waste Permit Number 6301-CDLF-1992 DIN 28725 Dear Mr. Beane: The Solid Waste Section (Section) has completed a technical review of the Assessment Monitoring Plan (DIN 28724) dated January 5, 2018 and submitted on your behalf by Golder Associates NC, Inc. for the unlined Moore County Active C&D Landfill, Solid Waste Permit Number 6301-CDLF-1992. The plan was submitted in response to groundwater exceedances of the regulatory standards and in accordance with 15A NCAC 13B .0545. Moore County will initiate an Assessment Monitoring Program at the active C&D landfill beginning with the first semiannual groundwater sampling event in 2018. Moore County is proposing to install two new nested replacement groundwater monitoring wells for MW-11S and MW-11D which are part of the C&D landfill’s compliance monitoring network. The County is concerned that the current monitoring wells are located too close to the limits of waste boundary at the C&D landfill. In addition, the County is requesting to replace groundwater monitoring well MW-15 during the same mobilization because the well has been dry. After the installation of the new well, MW-15R, MW-15 will be removed from the compliance monitoring network and a turbine vent will be added to help prevent migration of methane toward the property boundary. Additional parameters will be collected at the active C&D landfill. The additional parameters will include the full suite of constituents listed in the Appendix II of 40 CFR 258 and the required indicator parameters for C&D landfills (chloride, manganese, sulfate, iron, specific conductance, pH, temperature, alkalinity, total dissolved solids, and tetrahydrofuran). The first semiannual groundwater monitoring event (tentatively scheduled for April 2018) will be the first sampling event for these additional parameters. The proposed assessment monitoring well network will also include two additional closed and unlined Moore County MSW groundwater monitoring wells, MW-6 and MW-7, to further assess whether the groundwater impacts seen in C&D groundwater monitoring wells are caused by impacts from the upgradient MSW landfill. The two additional MSW monitoring wells will be sampled for and analyzed for the same list of assessment parameters. The data will then be used to complete an ASD Addendum, if data support that groundwater C&D landfill impacts are attributable to the MSW landfill. The proposed Assessment Monitoring well network for the C&D landfill includes the following: MW-5 (upgradient well), MW-4, MW-6, MW-7, MW-11SR, MW-11DR, MW-13S, MW-13D, MW-14, MW-16S, and MW-16D. Also included in the plan, Moore County is currently in negotiations with a property owner to purchase an adjacent tract of land and the owner is aware of the impacts to the property through verbal conversations with County staff. The private water supply well located on this property has been monitored since 1996. Finally, Moore County will continue conducting MNA as the corrective action at the closed and unlined upgradient MSW landfill until a new groundwater remedy is selected or the ASD is re-evaluated. Performance monitoring parameters collected under the current MNA program will continue as specified in the approved Assessment of Corrective Measures (ACM) submitted in 2005. Based upon the information provided within the Assessment Monitoring Plan, the plan is approved as described. Please do not abandon the groundwater monitoring wells MW-11S and MW-11D at this time and continue to collect groundwater level measurements from them. If you have any questions or concerns regarding this letter, please feel free to contact me by email at jaclynne.drummond@ncdenr.gov or by phone at 828.296.4706. Thank you for your continued cooperation with these matters. Sincerely, Jaclynne Drummond Hydrogeologist Solid Waste Section, Division of Waste Management NCDEQ cc sent via email: Adam Ulishney, Environmental Compliance Branch Head Jason Watkins, Field Operations Branch Head Ed Mussler, Permitting Branch Head Drew Hammonds, Eastern District Supervisor Amanda Freeman, Senior Environmental Specialist Elizabeth Werner, Permitting Branch Hydrogeologist Ming Chao, Permitting Branch Engineer Randy Gould, Moore County Public Works Director Ben Draper, Golder Associates NC, Inc.