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QWI09&AI7edUdaItW. Page 6 Dual Phase Extraction Pilot Test Report Project No.723.2 November 5,2004 ,., 3.2 Dual Phase Extraction from Well EW-1 On July 27, 2004 (Tuesday), the extraction hose (stinger) was lowered in well EW-1 and dual �. phase extraction began at approximately 9:30 A.M. The initial water level in EW-1 was noted [-37 feet below grade surface (bgs)] and then the stinger was lowered into groundwater to begin slurping the liquid from the well. The stinger was lowered incrementally as the well slowly dewatered until the stinger reached 50 feet bgs. It was left in this position. GTI recorded the treatment trailer effluent discharge meter at regular intervals. The meter 'r readings were then used to calculate groundwater extraction rates that varied 3 -6 gallons per minute (gpm) on July 27`h. The pumping data are included in Table 4, Appendix A and it is noted that the average pumping rate was 4.2 gpm on the July 27Th At 8:00 A.M. on the morning of July 28th (Wednesday), the system was discovered to be extracting less than one gallon per minute. The stinger was raised to allow the well to recharge and then lowered again to find an equilibrium level that would not dry out the well. At 9:15 A.M., American Valley pumped out the holding tank and transported 3100 gallons of groundwater off site for disposal. By 11:30 A.M. the stinger was set at 47 feet bgs and the well sustained a pumping rate approximating 3 gpm. The system was allowed to continue in this pumping configuration for another night. At 6:45 P.M., American Valley pumped out the holding tank and transported a second load of groundwater off site for disposal. The tank had a capacity of 5200 gallons and pumping calculations were performed to ensure the tank did not overfill. As indicated in Table 4 the average pumping rate was 2.4 gpm on the 28a'. But it is noted that this rate includes the low recharge period between midnight and 8:00 A.M. �.. 3.3 Dual Phase Extraction from Wells EW-1,VEW-1 and VEW-2 On July 29th at 9:00 A.M. (Thursday), the extraction rate was still approximately 3 gpm. At •- this point it was assumed that enough pumping data had been collected and GTI wanted to achieve maximum contaminant mass removal for the remainder of the test period. At 11:30 A.M. the system was reconfigured to extraction from EW-1, VIEW-1 and VEW-2 simultaneously. As noted in Table 4, the system sustained an average pumping rate of 3.6 gpm from the three wells on July 29". The system was allowed to continue in this pumping 46- configuration for another night. 3.4 Vapor Extraction From Wells EW-1 and VEW-1 On July 30`h at 9:00 A.M. (Friday), the extraction rate was 3.8 gpm. At 11:25 A.M. American Valley removed another load of groundwater with the groundwater extracted during the test totaling over 14,000 gallons. In order to achieve maximum contaminant removal from around the former dispenser island, the system was reconfigured to extract '� from EW-1 and VEW-1 only for the remainder of the test. At 6:00 P.M. the stinger was