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C704rcalTecwalru. Page 8 Dual Phase Extraction Pilot Test Report Project No 662 2 February 22,2005 measurements were made in the surrounding wells using magnehelic gauges provided by Mako at periodic intervals Each wells' vacuum was measured by placing a cap over the well ' and attaching a gauge to the cap's orifice The field measurements conducted by GTI staff are included in Table 5, Appendix A After five minutes of operation the vacuum was strong enough to start extracting groundwater from EW-2 (the initial water depth of 27 ft indicated a water column of five feet in the well) The system valves were adjusted to maximize air flow and reduce as much ' water intake as possible The system was left in this configuration for three hours and vacuum readings taken from the surrounding wells Since the system was still slurping water with low vacuum applied, the stinger was lowered to extract groundwater and the vapor only ' extraction attempts terminated at 12 40 ' 4.2 Dual Phase Extraction from Well EW-2 December 6 ' The extraction hose (stinger) was lowered in well EW-2 to 32 feet (bottom of well) and dual phase extraction began at approximately 13 00 The stinger was left in this position for the remainder of the test GTI recorded the treatment trailer effluent discharge meter at regular intervals The meter readings were then used to calculate groundwater extraction rates that started out 18 gallons tper minute (gpm) on December 6t' The pumping data are included in Table 5, Appendix A At midnight Monday, and again at 8 00 on the morning of December 7b (Tuesday), the system was discovered to be extracting less than one gallon per minute By this time only 1100 gallons of water had been extracted and it was decided to begin extracting from the deep well EW-1 in conjunction with well EW-2 4.3 Dual Phase Extraction from Wells EW-1 and EW-2 ' December 7 On December 7`�' at 1100, a second stinger hose was placed into well EW-1 The stinger was lowered to a position dust above the static water table (-27 feet) and vacuum applied to start ' slurping water The vacuum was pulling water out so quickly that the hose would repeatedly "deadhead" and lose vacuum The stinger was raised to about six feet above the water table (-20 feet bgs) By 12 00 the extraction rate had increased to approximately 2 6 gpm and the ' stinger was left in this position At 13 15 a water pick up was requested for American Valley to haul off the first load of accumulated water for disposal American Valley arrived at 14 20 and their first load of 3,400 gallons of water was removed At 16 00 the extraction rate had increased to 11 gpm and there was a concern that the extraction rate would exceed the holding tank capacity At 17 15 the extraction rate was