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HomeMy WebLinkAbout5001_JacksonCountyWCU_GWMR_20171116Correspondence: Amec Foster Wheeler Environment & Infrastructure, Inc. 1308 Patton Avenue Asheville, North Carolina 28806 Tel 828.252.8130 November 16, 2017 Mr. Roger Turk Western Carolina University 3476 Old Cullowhee Road Cullowhee, North Carolina 28723 Subject: Letter Report of Landfill Gas Monitoring WCU Closed Municipal Solid Waste Landfill Cullowhee, Jackson County, North Carolina NCDEQ Permit: 50-01 Amec Foster Wheeler Project 6252-15-0221 Dear Mr. Turk: Amec Foster Wheeler Environment & Infrastructure, Inc. (Amec Foster Wheeler) is pleased to present this Letter Report of Landfill Gas Monitoring for Western Carolina University’s (WCU’s) closed municipal solid waste landfill (MSWLF) located in Cullowhee, North Carolina (Figure 1). The scope of work for this monitoring event was described in Amec Foster Wheeler’s Addition of Scope Request for Environmental Services, dated May 5, 2016. This letter report summarizes background information, field activities, results, discussion and recommendations from landfill gas monitoring performed at the subject property. BACKGROUND INFORMATION WCU operated the MSWLF from approximately the 1960s until 1993. Jackson County also disposed of municipal solid waste at the landfill from approximately the early 1970s through the early 1980s. The landfill property is approximately 31.5 acres, approximately four acres of which contain the former landfill. The landfill was closed in accordance with the then applicable North Carolina Department of Environmental Quality (NCDEQ) closure standards (15A NCAC 13B 0.0510), and a closure letter was issued to WCU by NCDEQ on September 5, 1995. NCDEQ personnel conducted a facility audit on March 16, 2011, and determined that landfill gas monitoring at the landfill must be performed in order for the landfill to be in compliance with the post-closure conditions identified in the 1995 closure letter. In response to the audit, a Landfill Gas Investigation Work Plan, which described the preliminary landfill gas investigation, as well as the ‘full’ landfill gas investigation, was submitted to NCDEQ on October 19, 2011, and approved by NCDEQ in a letter dated November 29, 2011. Amec Foster Wheeler conducted the preliminary landfill gas investigation in January 2012 using the existing groundwater monitoring wells, and then Letter Report of Landfill Gas Monitoring November 16, 2017 WCU Closed Municipal Solid Waste Landfill, Cullowhee, North Carolina Amec Foster Wheeler Project 6252-15-0221 2 conducted semi-annual landfill gas monitoring utilizing the existing groundwater monitoring wells from August 2012 to November 2015 to comply with the post-closure conditions. The ‘full’ landfill gas investigation, which included the installation of eight permanent landfill gas monitoring wells, was performed in February 2016. Since the “full” landfill gas investigation has been implemented, monitoring of landfill gas has been conducted quarterly in accordance with NCDEQ Solid Waste Management rules (15A NCAC 13B.1626 (b)). FIELD ACTIVITIES On November 13, 2017, Amec Foster Wheeler personnel measured landfill gas at the eight landfill gas monitoring wells (LG-1, LG-2, LG-3S, LG-3D, LG-4, LG-5, LG-6 and LG- 7) at the Site (Figure 2). The landfill gas monitoring wells are screened in the unsaturated zone and located between the landfill and the Site’s property boundary. The landfill gas monitoring wells are fitted with a slip cap and ball valve to allow for measurement of potential landfill gas. A calibrated gas monitoring instrument, a Landtec GEM 2000+, was used to measure atmospheric pressure, as well as the following landfill gas parameters:  Methane (percent by volume)  Oxygen (percent by volume)  Carbon dioxide (percent by volume) The initial and stabilized readings for the above parameters were measured and recorded. The Solid Waste Section’s Landfill Gas Monitoring Data Form was used to record measurements and other relevant information and is attached. RESULTS AND DISCUSSION The Site landfill gas monitoring wells were tested for methane, carbon dioxide, and oxygen. Refer to the attached Landfill Gas Monitoring Data Form for the testing results. Concentrations of methane were not detected in the landfill gas monitoring wells. The regulatory limit for methane at a MSWLF property boundary is equal to the lower explosive limit of methane (15A NCAC 13B.1627 (d)). The recorded results from the eight landfill gas wells do not exceed this limit indicating that regulatory limits are not being exceeded at the Site. RECOMMENDATIONS Based on the results of this monitoring event, we recommend submitting a copy of this letter report to NCDEQ Solid Waste Section for their evaluation. We recommend continued quarterly monitoring of landfill gas at the subject property.