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F 4) ATTACHMENT A REMEDIAL SYSTEM PERFORMANCE EVALUATION Soil vapor extraction (SVE) and groundwater extraction were initiated on June 14, 2003 A brief description and performance evaluation of the remedial system during the third quarter 2003 is presented below Certified laboratory analytical reports, chain -of -custody documentation, and field data sheets are included as Attachment A -A SVE System The SVE system was started on June 14, 2003, and is comprised of 6-SVE wells (SVE-1, SVE-2, MW -1, MW -2, MW -4, and EW -7) The SVE system utilized a Thermtech VAC 50 thermal/catalytic oxidizer (Cat -Ox) as the abatement device The SVE system operates under San Joaquin Valley Air Pollution Control District Permit to Operate N-4826-1-0 The SVE system was approximately 66% operational this quarter Downtime was due to high temperature shut -offs and a car crashing into the remedial compound Approximately 16,230 pounds (lbs) of TPHg, 894 Ib of benzene, and 1,753 lb of MtBE were removed this quarter An estimated 16,698 lbs of TPHg, 94 lbs of benzene, and 1,809 lbs of MtBE have been removed since remediation was initiated at the site SVE system operational and analytical data, including hours of operation, applied vacuum, flow rate, ambient dilution status, field FID measurements, influent TPHg and benzene concentrations, and mass removal data are presented in Table A-1 Emissions data is provided in Table A-2 Graphical illustrations of TPHg and benzene mass removal and concentration data are shown on Figures A-1 and A-2 Groundwater Extraction System The GWE system is comprised of submersible pumps installed in 2 GWE wells (EW -1 and EW -6) and connected to an air stripper and three 2,000 -granular activated carbon vessels Extracted groundwater is treated by the air stripper and carbon vessels prior to discharge to the City of Stockton sanitary sewer During the third quarter of 2003, the GWE system pumped 67,200 gallon of groundwater at a pumping rate of 1 2 gpm Approximately 47 5 pounds (lbs) of TPHg, 1 53 Ib of benzene, and 615 lb of MtBE were removed this quarter An estimated 47 5 lbs of TPHg, 1 53 lbs of benzene, and 615 lbs of MtBE have been removed since remediation was initiated at the site GWE system operational data is included in Table A-3 Groundwater Batch Extraction Batch groundwater extraction was initiated in March 2002 and consisted of extracting groundwater from onsite wells MW -1, MW -4, MW -6, and EW -1 with a vacuum truck Batch extraction was performed twice a month until the construction of the permanent remedial system began in November 2002 Batch extraction was re -started in September 2003 as an interim remedial approach to reduce petroleum hydrocarbon concentrations in offsite extraction wells and for offsite plume control pending connection of