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S E C O R <br /> ATTACHMENT A <br /> REMEDIAL SYSTEM PERFORMANCE EVALUATION <br /> A dual phase extraction (DPE) system, consisting of the application of combined soil vapor extraction <br /> (SVE) and groundwater extraction (GWE) technologies, was initiated at the site on June 14, 2003 A <br /> brief description and a performance evaluation of the DPE system during the first quarter 2004 are <br /> presented below Certified laboratory analytical reports, chain-of-custody documentation, and field <br /> data sheets are included as Attachment A-A <br /> Soil Vapor Extraction <br /> SVE was started on June 14, 2003 The SVE portion of the DPE system is comprised of 6 SVE wells <br /> (SVE-1, SVE-2, MW-1, MW-2, MW-4, and EW-7) and a Thermtech VAC 50 thermal/catalytic oxidizer <br /> (Cat-Ox) as the abatement device The SVE system operates under San Joaquin Valley Air Pollution <br /> Control District Permit to Operate N-4826-1-0 <br /> The SVE system was approximately 85% operational this quarter Approximately 676 pounds (lbs) of <br /> TPHg, 1 5 lbs of benzene, and 10 7 lbs of MtBE were removed this quarter An estimated 20,784 lbs <br /> of TPHg, 92 lbs of benzene, and 1,690 lbs of MtBE have been removed since remediation was <br /> initiated at the site <br /> SVE system performance data, including hours of operation, applied vacuum, flow rate, ambient <br /> dilution status, flame ionization detector (FID) field measurements, influent TPHg and benzene <br /> concentrations, and estimated mass removal data are presented in Table A-1 Sod vapor emissions <br /> data is provided in Table A-2 Graphical illustrations of sod vapor TPHg and benzene mass removal <br /> and concentration data are shown on Figures A-1 and A-2 <br /> Groundwater Extraction System <br /> The GWE portion of the DPE system is comprised of submersible pumps installed in 2 GWE wells <br /> (EW-1 and EW-6), which are connected to an air stripper and three 2,000-granular activated carbon <br /> vessels Extracted groundwater is treated prior to discharge to a City of Stockton sanitary sewer line <br /> During the fourth quarter 2003, the GWE system pumped and treated approximately 223,040 gallons <br /> of groundwater, removing approximately 14 4 lbs of TPHg, 0 40 lbs of benzene, and 35 6 lbs of MtBE <br /> An estimated 89 2 lbs of TPHg, 3 55 lbs of benzene, and 123 8 lbs of MtBE have been removed by <br /> GWE since the DPE system began operating at the site GWE system performance data is included <br /> in Table A-3 Groundwater treatment effluent data is included in Table A-4 Graphical illustrations of <br /> TPHg and benzene mass removal from extracted groundwater and groundwater concentration data <br /> are shown on Figures A-3 and A-4 <br />