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Brendan Kenny
<br />Central Valley Regional Water Quality Control Board
<br />January 15, 2024
<br />www.arcadis.com
<br />Forward Landfill 4Q23 CAP Rpt_01152024
<br />3/4
<br />Between September 27, 2023 and December 28, 2023, the GWTS treated approximately 43,705,177 gallons of
<br />extracted groundwater, which represents an average flow rate of 475,056 gallons per day. Based on the extracted
<br />volumes and measured VOC concentrations, the GWTS removed approximately 0.93 pounds of VOCs during the
<br />reporting period. The Del-Tech downtime log for the reporting period is included in Attachment A. The operation of
<br />the GWTS was affected by the following events during the reporting period:
<br /> On November 25, 2023, all GWE wells were turned off in preparation for conveyance line cleaning. Line
<br />cleaning activities were completed on November 27 and 28, 2023. On December 1, 2023, the system was
<br />restarted; however, due to high influent pressures caused by buildup in the lead GAC Vessel (GAC Unit #1)
<br />the system was turned off until the carbon could be changed.
<br /> Higher pressures had caused some compaction of the carbon within the lead GAC vessel (GAC Unit #1). The
<br />layer of hardened carbon was physically broken up on December 8, 2023; GWE well EW-5 was then
<br />restarted.
<br /> On December 13, 2023, GWE well EW-5 was turned off to allow water to drain from the lead vessel (GAC
<br />Unit #1); the carbon in this vessel was then changed out.
<br /> On December 14, 2023, following the carbon changeout, the vessel order was switched so that GAC Unit #2
<br />and GAC Unit #1 were in lead and lag positions, respectively. GWE wells EW-2, EW-3R, and EW-5 were
<br />restarted on December 16, 2023.
<br /> On December 17, 2023, GWE wells EW-1 and EW-4 were restarted.
<br />All five of the active groundwater extraction wells (EW-1, EW-2, EW-3R, EW-4, and EW-5) and the treatment
<br />system were operational throughout the majority of the reporting period, except for brief maintenance activities
<br />and for the shutdowns as described above. Flow rates were continuously monitored and adjusted to increase
<br />groundwater capture with the upgraded treatment system.
<br />Landfill Gas Collection and Control System
<br />During the Fourth Quarter of 2023, the landfill gas collection and control system (GCCS) at the Austin Unit of the
<br />Forward Landfill included 215 active landfill gas extraction wells. The landfill gas collected from these wells is
<br />routed and split between the Ameresco Landfill Gas to Energy Facility (LFGEF) and Forward’s Flares A-1 and A-2
<br />for thermal destruction.
<br />The landfill gas extraction wells are monitored semimonthly (twice per month) by SCS Field Services of Modesto,
<br />California (SCS). The SCS semimonthly monitoring results for Point of Compliance wells and individual wells are
<br />included in Tables 1 and 2 of the Quarterly Program Update, which is included as Attachment C. Probes GP-10D,
<br />GP-10M, and GP-10S had exceedances of methane greater than one percent by volume. In addition, probes GP-
<br />2AD, GP-2AM, GP-4AM, GP-4AS, GP-6AM, GP-10D, GP-10M, GP-10S, GP-11D, GP-11S, GP-12D, GP-12M,
<br />and GP-13D had VOC concentrations above 10 parts per billion (ppb). As required, on October 5, 2023 annual
<br />samples were obtained and analyzed using Environmental Protection Agency Method TO-15. The next annual
<br />sampling event will be performed by the end of November 2024, or as requested by the client. As recorded in
<br />Table 1, VOCs were detected at concentrations ranging from 100 ppb in GP-4AM to 4,300 ppb in GP-11D.
<br />The landfill GCCS undergoes periodic maintenance and tuning to produce the highest percentage of landfill gas
<br />and to minimize the collection of oxygen. The general operation of the GCCS during the Fourth Quarter of 2023 is
<br />documented by SCS (Attachment C). During the Fourth Quarter 2023, the instantaneous total flow rate was
<br />measured at the site and included both LFG flares and the Ameresco LFGTE Facility. The instantaneous total
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