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3.0 SOIL VAPOR EXTRACTION SYSTEM OPERATION <br /> On June 2, 1999, ENSR started the thermal oxidizer sod vapor extraction (SVE) system in the <br /> presence of an inspector from the San Joaquin Valley Unified Air Pollution Control District <br /> (SJVUAPCD) <br /> According to ENSR, five extraction wells (VW-1 D, VW-1 S, VW-2S, VW-3 and VW-4) were utilized <br /> by the system, during startup The system parameters at startup included a flow rate of 214 <br /> standard cubic feet per minute (scfm), vacuum of 65 inches of water column, and a concentration <br /> of volatile organic compounds by Flame Ionization (FID) of 2,100 parts per million by volume <br /> (ppmv) <br /> During startup, ENSR collected vapor samples for analysis to monitor the efficiency of the SVE <br /> system The system influent soil vapor sample contained 4,960 milligrams per cubic meter (mg/m3) <br /> of purgeable hydrocarbons, 109 mg/m3 of benzene, 650 mg/m3 of toluene, 148 mg/m3 of <br /> ethylbenzene, and 560 mg/m3 of xylenes This translated to an initial mass recovery rate of 123 5 <br /> pounds per day Between startup on June 2, 1999 and the last monitoring of the third quarter of <br /> 1999 on September 15t" a total mass of 5 524 1 pounds of hydrocarbons <br /> p p had been removed <br /> lbDuring the fourth quarter of 1999, ENSR extracted exclusively from VW-2S and VW-3, since these <br /> two wells have shown the highest concentrations of gasoline hydrocarbons During the quarter, an <br /> air sparge pump was installed in MW-1 The sparge pump operates daily from 11 00 am to 1 00 <br /> pm and 11 00 pm to 1 00am The SVE system operated with an up-time of greater than 90% <br /> During the fourth quarter of 1999, ENSR monitored the system on November 3`d and December 2nd <br /> On December 2, 1999, the system was operating at 75 scfm, with a vacuum of 34 inches of water <br /> column The mass recovery rates have declined to 8 03 pounds per day <br /> I <br /> Between September 15 and December 2, 1999, a total of 1,542 4 pounds of hydrocarbons were <br /> removed by the system Since startup on June 2, 1999, a total of 7,066 5 pounds have been <br /> removed <br /> 6 <br /> I <br />