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There were originally four SVE remediation system wells (VW1 through VW4) VWI 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 ATC started the SVE system continuously on December 19, 2002 After the initial start-up operations, VW3 was taken off line to reduce water production and VW4 was partially closed off but remains 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 MW1 was converted to a vapor extraction well on February 10, 2004 The well completion of MW1 was altered with a stinger, set at approximately 32 feet bgs The SVE system was not operational during the first quarter 2004 and was subsequently removed by the vendor without notice during the month of November Water Treatment Syste Components of the water treatment system which are located within the remediation compound include the knockout tank on the former thermal oxidizer (now replaced with a 300 cfm thermal oxidizer), one 1,000-gallon drop tank, three transfer pumps, 2,000 pound canisters connected in series containing aqueous-phase granular activated carbon, associated piping, control valves, pressure gauges, flow meters, instrumentation and controls From the effluent end of the lag canister, fluid is pumped Into a 100-gallon tank where it is discharged to the sanitary sewer system located on the south side of the on site building • The former vapor extraction system, groundwater treatment, and discharge system as previously configured were started up on December 20,2003 During initial start up of the vapor extraction system, approximately 25 gallons of groundwater per hour were extracted from the four vapor wells (VW 1 —VW4) ATC closed the valves on VW 1 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 system ) ATC submitted the necessary permit application information for the discharge of treated groundwater and on November 6, 2002 the 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 licensed plumber during the week of November 25, 2002 When the system is operated, groundwater is separated from the extracted vapor in a 50-gallon knockout tank located near the 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 transfers 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 s lenviro1625961quart1yl1gr-2005 doc 4 ATC ASSOCIATES INC