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i SVESVESystem ' The current SVE equipment (i e , 300 standard cubic feet per minute (SCFM) thermal oxidizer) was installed at the site on April 7, 2005, replacing a previous SVE unit The SVE unit was connected to the existing 500-gallon propane above ground storage tank (AST) for supplemental fuel supply, necessary ' hoses, pipes, gauges to transfer the propane, subsurface piping and wellhead connections between the SVE remediation wells, the AS remediation wells and the fenced remediation equipment compound ' Four SVE remediation system wells (VW1 through VW4) were originally utilized at the site VW1 is screened between 10 and 30 feet bgs VW2 is screened between 20 and 35 feet bgs VW3 and VW4 were screened between 15 feet bgs and 25 feet bgs Each SVE wellhead connection includes a gate valve, ' vacuum gauge, sampling port,and flow rate measurement port After the initial start-up operations for the original SVE system, VW3 was taken off line to reduce water production and VW4 was partially closed off but remained on line In July of 2004, the completions of VW1 and VW2 were altered to further reduce produced water These wells now include stingers set at approximately 28 feet bgs and 32 feet bgs, respectively. MW 1 was converted to a vapor extraction well on February 10, 2004 The well completion of MW 1 was altered with a stinger set at approximately 32 feet bgs Water Treatment System The SVE/AS system, groundwater treatment and discharge system (as previously configured) were started up on December 20, 2003 A water treatment system is required for the produced water associated with the SVE wells Components of the water treatment system include the knockout tank, located within the remediation ' compound, one 1,000-gallon drop tank, three transfer pumps, two 2,000 pound canisters connected in series containing aqueous-phase granular activated carbon (GAC), associated piping, control valves, pressure gauges, flow meters, Instrumentation and controls Treated water is pumped from the effluent end of the lag canister Into a 100-gallon tank, where it is discharged to the sanitary sewers stem located ' g �Y Y on the south side of the on site building ' During Initial start up of the original vapor extraction system, approximately 25 gallons of groundwater per hour were extracted from the four vapor wells (VWI —VW4) ATC closed the valves on VWI and VW2 and only extracted from VW3 and VW4, which are screened approximately two feet above the ' current water level Seven gallons of groundwater per hour were extracted from VW3 and VW4 To operate the vapor extraction system more efficiently, ATC modified the vapor extraction system to ' include groundwater treatment and discharge to the City of Stockton sewer system (This is the groundwater that accumulates during operation of the vapor extraction side of the system ) ATC submitted the necessary permit application Information for the discharge of treated groundwater and on November 6, 2002 the City of Stockton Department of Municipal Utilities (DMU) issued the Groundwater Discharge Permit (GDP) Following the issuing of the GDP, approximately 50 feet of 3- inch diameter, ABS pipe was placed on the surface of the site from the remediation compound to a discharge point located inside the bathroom of the on-site building The ABS pipe was connected to the existing sewer discharge line by a California licensedurin lumber dthe week of November 25, 2002 P g s lenviro1625961quart1y\1gr-2006 doc 4 ATC ASSOCIATES INC