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' Third Quarter SVES Report - Ultramar #696 Lodi 10 November 1992 Concentrations generally declined at the individual extraction wells ' with vapor levels at MW-19, the only remaining "hot spot" on the system, declining almost 50% from the previous monitoring Ambient dilution remained closed with the system drawing about 54 scfm of air ' from the soil . No valve positions were changed on this date with the system pulling from only 3 extraction wells; MW-19, MW-20, and MW--34 Wells MW-20 ' and MW-34 were generally always left open regardless of concentration as a precaution to prevent offsite mitigation of the contaminants. ' Extraction well MW-5 was temporarily opened and then reclosed when it was determined that opening this valved reduced the lbs/day mass removal rate. The SVES wass extracting approximately 12 lbs/day of hydrocarbons from the soil at a vacuum of 8.2" lig on this date. 17 July 1992 Restart Visit ' The SVES went down shortly after the 14 July monitoring, again due to an apparent power outage associated with major construction activities involved with the building of a nearby shopping center. An automatic restart device was ordered for the system. After the system was restarted, a verification vapor sample was obtained from MW-19 to document the progress of remediation at this ' single remaining "hot spot". The laboratory analysis of this sample indicated a hydrocarbon concentration of 1,101 ppm suggesting that further remediation was needed for this location. 29 July 1992 Monitoring- The system only operated about a day following the 17 July restart, again going down due to a construction related power outage. The SVES was restarted 28 July and purged a full 24 hours prior to monitoring. ' The operation was stable on this date and required no adjustments. The SVES remained extracting from only 3 wells at a vacuum of 8 2" Hg. The influent concentration dropped to about 458 ppm with the system extracting approximately 9 lbs/day of hydrocarbon from the soil . A verification vapor sample was again obtained from MW-19. The laboratory results indicated that the concentration had declined to 790 PPM 1 ' - 3 -