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Brendan Kenny
<br /> Central Valley Regional Water Quality Control Board
<br /> July 15, 2026
<br /> Remediation Systems Operations and Performance Summary
<br /> CAO Task 9.a indicates that quarterly program updates shall include information on remedial systems during
<br /> each reporting period. A summary of the Site's GWTS, residential GWTSs, and the facility's landfill GCCS are
<br /> provided in this Program Update. Additional details regarding the Site's GWTS (submitted by July 31, 2026) and
<br /> the residential GWTSs (submitted by August 1, 2026) are provided under separate cover in the following reports:
<br /> • Second Quarter 2026 Groundwater Treatment System Monitoring Report; and
<br /> • Second Quarter 2026 Residential Groundwater Treatment Systems Monitoring Report.
<br /> Groundwater Extraction and Treatment System
<br /> A GWTS is operated at the Site to address detections of volatile organic compounds (VOCs) in groundwater in
<br /> accordance with the WDRs outlined in the Order. The California State Water Resources Control Board Monitoring
<br /> and Reporting Program (MRP)Table 19 lists six groundwater extraction wells as part of the GWTS (EW-1, EW-2,
<br /> EW-3R, EW-4, EW-5, and CDCR-EW-1). Five of the six groundwater extraction wells listed in Table 19 of the
<br /> MRP (EW-1, EW-2, EW-3R, EW-4, and EW-5) are monitored bi-weekly, as they are the only extraction wells that
<br /> are part of an operational system. Extraction well CDCR-EW-1 is not currently part of an operational remedial
<br /> system and therefore is not monitored bi-weekly. Additional offsite extraction wells (CDCR-EW-2, CDCR-EW-3,
<br /> CDCR-EW-4, and CDCR-EW-5)are not included in the MRP and not connected to an operational remedial
<br /> system. Due to absence of an operational remedial system at the five offsite extraction wells, the wells are not
<br /> monitored bi-weekly as part of the corrective action program. The five offsite extraction wells were added to the
<br /> routine quarterly monitoring program in the second quarter of 2025 and are suggested to be included in the next
<br /> revision of the MRP.
<br /> The extracted groundwater is treated by two, 10,000-pound granulated activated carbon (GAC)vessels that were
<br /> installed in January 2020.
<br /> During the reporting period, the GWTS was inspected and monitored bi-weekly by Del-Tech Geotechnical
<br /> Support(Del-Tech)of Oakdale, California. Flow rates from the extraction wells were routinely monitored and
<br /> adjusted, if needed, to confirm groundwater capture within the treatment area. Del-Tech's field inspection forms
<br /> are included in Attachment 1.
<br /> During the second quarter, the GWTS treated approximately 46,706,961 gallons of extracted groundwater, which
<br /> represents an average total flow rate of approximately 518,966 gallons per day. Based on the extracted volumes
<br /> and analytical VOC concentrations, the GWTS removed approximately 1.08 pounds of total VOCs during the
<br /> reporting period. Del-Tech's downtime log for the reporting period is included in Attachment 1. The GWTS was
<br /> operational throughout the reporting period, except for the following downtime events, which indicate the system
<br /> was operational for 98 percent of the time (a total of 1,983 hours of system operation between the beginning of
<br /> the reporting period through the final visit of the quarter on June 24, 2026):
<br /> • On April 23, 2026, it was observed that wells EW-2, EW-3R, EW-4, and EW-5 were found to be offline
<br /> upon arrival at the system. It is unknown how long the wells had been offline; however, the wells were last
<br /> recorded as operational on April 8, 2026.
<br /> • On April 23, 2026, all extraction wells were turned off to perform GAC changeout in the lead GAC
<br /> vessel. After the GAC changeout occurred, the lead/lag vessel order was switched. All extraction
<br /> wells were restarted on April 25, 2026.
<br /> • On May 2, 2026, extraction well EW-2 was momentarily turned off to remove the flow meter as it was not
<br /> reading accurately, it was restarted shortly after, although the flow meter was still not operational.
<br /> www.arcadis.com 2/4
<br /> Forward Landfill 2Q26 CAP Update_07.15.2026
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