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26 August 2013 <br /> AGE Project No. 95-0130 <br /> Page 5 of 9 <br /> 3.1. GROUNDWATER EXTRACTION-TREATMENT OPERATION <br /> During the 2nd quarter 2013, extraction wells EW-1, VW-1C, VW-2A and VW-3A were <br /> selectively operated. All extracted groundwater from EW-1, VW-1 C, VW-2A and VW-3A <br /> was routed from the extraction wells to a holding tank; from the holding tank, water was <br /> treated by passing through three 2,000 pound media vessels containing liquid phase <br /> granular activated carbon (GAC). Following treatment,waterwas discharged underground <br /> via 1-inch diameter PVC piping to the City of Stockton sewer system; discharge piping is <br /> connected to a sewer clean-out located in the eastern section of the site, approximately <br /> 100 feet east of the GWET remediation system. <br /> Based on effluent flow meter readings (Table 1), approximately 202,430 gallons of treated <br /> water were extracted, treated and then discharged to the City of Stockton sewer system <br /> between 18 March and 17 June 2013 under City of Stockton Department of Utilities <br /> Ground Water Discharge Permit (dated 14 December 2009). <br /> 3.2. GROUNDWATER EXTRACTION-TREATMENT SAMPLING PROCEDURES <br /> GWET influent and effluent water samples were collected on a monthly basis from valved <br /> sampling ports located upstream (influent) and downstream (effluent) of the GWET <br /> remediation system.Additionally, intermediate grab watersamples were collected afterthe <br /> first carbon media vessel (GAC-1). All grab water samples were collected utilizing 40-ml <br /> EPA-approved volatile organic analysis (VOA) vials without a sample preservative and <br /> effluent samples within 1-liter amber bottles. Care was taken to ensure that visible air <br /> bubbles were not present in the vials after filling and capping. Groundwater sample <br /> containers were labeled with a sample designation, date, time, and sampler's initials. <br /> 3.3. LABORATORY ANALYSIS OF GROUNDWATER EXTRACTION <br /> AND TREATMENT <br /> Influent, intermediate and effluent grab water samples were logged on a chain of custody <br /> form, placed in a chilled container and transported to Cal Tech Environmental Laboratory <br /> (CTEL), a California Department of Public Health (CDPH)-certified laboratory to be <br /> selectively analyzed for: <br /> • TPH-g by EPA Method 8015 Modified (influent only); <br /> • Total Recoverable Petroleum Hydrocarbons (TRPH)by EPA Method 1664 (effluent <br /> only); and <br /> Advanced GeoEnvironmental,Inc. <br />