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I • 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 Licensed Plumber during the week of November 25, 2002 Groundwater is currently separated from the extracted vapor in a 50-gallon knockout tank located on the I thermal oxidizing unit The knockout tank is equipped with water level sensors and when the knockout tank is approximately 80% full of groundwater, a transfer pump transfers the water from the knockout tank into a 1,000-gallon poly drop tank that is also located inside the remediation compound The drop tank is equipped with water level sensors and when the drop tank is approximately 80% full of groundwater, a second transfer pump pumps the water from the drop tank through the carbon filtration system The transfer pump stops pumping when the drop tank is reduced to 55% capacity ' The aqueous-phase carbon filtration system originally consisted of three ASC200 200-pound carbon vessels containing liquid-phase granular activated carbon The three ASC200 carbon vessels were ' connected in series by a hose connection system These canisters were replaced in December of 2003 with two 2000- pound carbon canisters to reduce the frequency and number of carbon change-outs and the associated operation and maintenance (O&M) costs The two carbon vessels are setup in series with sampling ports before the lead vessel, in between the lead and lag vessels, and after the lag vessel AS Treatment System The AS system consists of a GAST 2567-P132-T908X rotary vane, 2- horse power, air compressor This blower is capable of injecting at a maximum of 20 pounds per square inch (PSI) at low flow rates The maximum flow rate is approximately 21 SCFM IThere are two AS remediation wells (AS 1 and AS2), which are installed to 40 feet bgs with five feet of well screen Each AS wellhead connection includes a gate valve, pressure gauge and flow rate ' measurement port ATC started the AS system on February 13, 2003 REMEDIATION SYSTEM MONITORING ' Vapor Extraction System Monitoring During the third quarter 2004 reporting period, ATC personnel monitored the vapor extraction system on July 26, August 26, and September 27, 2004 Parameters monitored in the field Included vapor extraction flow rates, hydrocarbon vapor concentrations, groundwater extraction rate, total groundwater discharged to the City of Stockton sanitary sewer, and total hours of system operation Field monitoring data are ' contained in Attachment 3 On July 26, August 26, and September 27, 2004, ATC personnel collected vapor samples from VW1, VW2, VW4, MW1, and from the influent and effluent vapor streams of the vapor extraction system The samples were transported under chain-of-custody documentation to SunStar Laboratories, Inc (Environmental Laboratory Accreditation Program Certificate No 2250) in Golden, Colorado and were ' analyzed for VOCs by EPA Method TO-14 On July 26, August 26, and September 27, 2004, ATC personnel collected water samples from the groundwater treatment and discharge component of the vapor extraction system Water samples were s\enviro1625Wquartly�3gr-2004 doc 5 ATC Associates Inc 1