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Brendan Kenny
<br />Central Valley Regional Water Quality Control Board
<br />April 15, 2025
<br />www.arcadis.com
<br />Forward Landfill 1Q25 CAP Update_04152025
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<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. MRP Table 19 lists six groundwater extraction wells as part of
<br />the GWTS (EW-1, EW-2, EW-3R, EW-4, EW-5, and CDCR-EW-1); however, only five groundwater extraction
<br />wells (EW-1, EW-2, EW-3R, EW-4, and EW-5) are currently connected and operating. Extraction well CDCR-EW-
<br />1, along with the additional offsite extraction wells previously installed and not included in the MRP (CDCR-EW-2,
<br />CDCR-EW-3, CDCR-EW-4, and CDCR-EW-5), are not connected to a remedial system and, therefore, will not be
<br />monitored monthly as part of the corrective action program. However, these five extraction wells will be added to
<br />the routine quarterly monitoring program beginning in second quarter 2025.
<br />The extracted groundwater is treated by two 10,000-pound granulated activated carbon (GAC) vessels, which
<br />were installed in January 2020.
<br />During the First Quarter of 2025, the GWTS was inspected and monitored bi-weekly by Del-Tech of Oakdale,
<br />California. Flow rates from the extraction wells were routinely monitored and adjusted, if needed, to confirm
<br />groundwater capture within the treatment area. The Del-Tech bi-weekly field inspection forms are included in
<br />Attachment A.
<br />Between December 20, 2024 and March 29, 2025, the GWTS treated approximately 50,642,900 gallons of
<br />extracted groundwater, which represents an average total flow rate of 511,544 gallons per day. Based on the
<br />extracted volumes and measured VOC concentrations, the GWTS removed approximately 0.59 pounds of VOCs
<br />during the reporting period. The Del-Tech downtime log for the reporting period is included in Attachment A. The
<br />treatment system was operational throughout the reporting period except for the following downtime events, which
<br />indicates 98 percent uptime (a total of 2,328 hours of system operation).
<br /> On January 9, 2025, all groundwater extraction wells were turned off to allow for the removal and
<br />replacement of the GAC in GAC Vessel #2, which was the lead treatment vessel at that time. After the
<br />GAC change out, the vessel order was switched so that GAC Vessel #1 and GAC Vessel #2 were in lead
<br />and lag positions, respectively. All groundwater extraction wells were restarted on January 10, 2025.
<br /> On February 5, 2025, a power disturbance caused EW-3R and EW-5 to shut down. Later that day, EW-
<br />3R was brought back online, but EW-5 required additional electrical repairs. EW-5 was brought back
<br />online on February 10, 2025, after the completion of electrical repairs.
<br />Low concentrations of VOCs (up to 2.14 micrograms per liter of total VOCs) were detected in the six influent
<br />samples collected. No VOCs were detected above the practical quantitation limit in the effluent samples collected
<br />for the Order.
<br />Per the WDRs in the Order, the GWTS effluent limit for VOCs is non-detect. Given the results from the effluent
<br />samples collected, the GWTS was compliant with the WDRs during this reporting period. Details regarding
<br />influent and effluent sampling, field sheets, and copies of the laboratory reports are provided under separate
<br />cover in the First Quarter 2025 Groundwater Treatment System Monitoring Report.
<br />Residential Treatment Systems
<br />During the First Quarter of 2025, Forward, Inc. continued to provide operation, monitoring and maintenance for 14
<br />residential water treatment systems on Austin and Newcastle Roads. The treatment systems are composed of
<br />inline sediment filters and dual GAC vessels that remove VOCs from the water prior to entering the residence.
<br />Regular system sampling and maintenance on the treatment systems is performed by Del-Tech. A separate
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