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GeoHydrologic Consultants, Inc <br /> Operation of the vapor extraction unit entailed that separated liquids were automatically <br /> transferred into onsite storage tank while hydrocarbon vapors were abated with a San <br /> Joaquin County Air Pollution Control District (SJCAPCD) permitted propane fired <br /> thermal oxidizer <br />' 5.1 Multi-Phase Extraction Pilot Test (EW-5D <br />' On March 17, 2005, an eight-hour multi-phase extraction pilot test was conducted by <br /> extracting vapor and pumping groundwater from well EW-5D <br />' • The vacuum applied by the vapor extraction process ranged from 10 2 to 26 0 <br /> inches of Hg <br /> 0 The flow rate varied between l 1 and 167 scfm <br /> a The PID readings for the total undiluted influent varied from non-detect to 690 <br /> ppm V <br /> • The initial vacuum in observation well MW-5 (9 feet away) was recorded at 0 00 <br />' inches of water then remained at a pressure of 0 01 inches of water <br /> • The vacuum in observation well TB-9 (23 feet away) alternated from 0 00 to 0 01 <br />' inches of water while alternating to positive pressure readings as high as 0 05 <br /> inches of water <br />' * The vacuum in observation well TB-11 (20 feet away) alternated from 0 00 to a <br /> positive pressure reading of 0 06 inches of water <br />' • The vacuum in observation well TB-10 (34 feet away) varied from 0 00 then <br /> alternated to a positive pressure of 0 06 inches of water <br />' • The vacuum in observation well MW-4 (51 feet away) varied from 0 00 to a <br /> positive pressure of 0 01 inches of water <br />' • The vacuum observed in well TB-7 (34 feet away) varied from 0 00 to 0 06 <br /> inches of water <br /> Groundwater was extracted using a two-inch diameter variable speed stainless-steel <br /> Grunfos electric submersible pump The pump intake was placed approximately two feet <br /> from the bottom of the well during the test, which correlates to approximately 33 feet <br /> below static water levels at a depth of approximately 83 feet deep The static water level <br /> for this well was measured at a depth of 50 20 feet At 1 25 hours into the 8 hour test, <br /> depth to water was measured in extraction well EW-5D at approximately 65 00 feet <br /> (approximately 15 feet of drawdown), which correlates to the approximate depth of the <br /> top of the screened interval of the four-inch diameter extraction well A total of 1,320 <br /> Igallons of water was extracted from this well during the 8-hour test, at an average flow <br /> ITOC 171 Pilot Study Page 10 <br />