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rINTERNATIONAL TECHNOLOGY CORPORATION <br /> 2.3 Soil Vapor Extraction Pilot Test <br /> The SVE test was conducted over a 6 hour period on January 21, 1992 by representatives of <br /> IT Corporation. During the test, air was extracted from the horizontal piping and stubbed out <br /> near monitoring wells MW-3 and MW-7 (Figures 1 and 2). Air was extracted for 3 hours <br /> with a Rotron Model DR 454, 1 horsepower blower at 100% of the blower capacity. The <br /> air flow rate was monitored with a Kurtz Model 1440 velocity meter. Vacuum was <br /> 1 monitored at vadose wells VW-1 and VW-2 and at monitoring wells MW-5, MW-6 and MW- <br /> 7. The blower inlet and outlet pressures were also monitored. <br /> Extracted vapors were routed through two carbon canisters (in series) prior to discharge. <br /> Discharge air was periodically evaluated for oxygen concentration/lower explosive limit and <br /> petroleum hydrocarbon concentration using a combustible gas indicator and a photoionization <br /> detector respectively. These tests were conducted to insure breakthrough had not occurred. <br /> Extracted soil gas samples were collected from the 4" dia stub out for the horizontal piping. <br /> Soil gas samples were collected 1 hrs and 3 hrs after initiation of the SVE test. A blank <br /> air sample (ambient air) was collected to examine background air quality. The samples were <br /> submitted to Quanteq Laboratories in Pleasant Hill, California. Samples were analyzed for <br /> total petroleum hydrocarbons (TPH) as gasoline and benzene, toluene, ethyl benzene and total <br /> xylenes (ETEX) by EPA methods 5030 and 8020, respectively. <br /> Following sample collection, the vacuum was reduced from 100% to 60% of blower capacity. <br /> The respondent induced pressure changes were monitored at the surrounding wells for one <br /> hour. <br /> 2.4 Field Observations <br /> The following observations were made during SVE test excavation: <br /> the volume of soil gas extracted under vacuum appears to be higher than expected <br /> for the observed substrata (clays) <br /> ® a measurable vacuum was induced in all wells monitored <br /> the vacuum measured in the surrounding wells stabilized in less than 1 hour after <br /> each change at the extraction stub out <br /> the hydrocarbon concentration in the extracted soil gas was substantial and <br /> appeared to increase over the duration of the test <br /> the temperature rise of the extracted air was minimal. <br /> MZ/03-10-92/UST/0087MER 4 <br />