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R603 UPDATE-29 6/07/94 for a total of 24, 902 out of 35,443 hours (70t) . As of May 25, 1994 an estimated 73799 pounds of gasoline range hydrocarbons have been destroyed, see Tables in Appendix C-Air Monitoring Report . Since February 18, 1993 the vapor recovery/destruction has been declining from an average above 200 pounds per day of gasoline range hydrocarbons to a present low of 9 9 pounds per day of gasoline range hydrocarbons on April 26, 1994 . Presently the system is destroying a range from 14 to 7 pounds per day of gasoline range hydrocarbons, see Appendix C CONDENSATE REMOVAL BY LTT Condensation from vapor extraction is collected in moisture drop out tanks constructed of 12" PVC pipe, before the manifold, to prevent moisture build up on the vacuum pump filter All fluids removed from the condensation traps are placed in the 1000 gallon "ConVault" As of May 23 , 1994 , 5248 gallons of water/condensate and 48 . 75 gallons of product have been removed from the subsurface of this site 4 . 0 SUMMARY There has been no evidence of floating product or product sheen on the ground water in MWl since April 14 , 1992 and MW3 and MW10 since November 11, 1992 Only occasional product sheen is found with the condensate recovered from the vapor extraction moisture dropouts and manifold Vapor recovery has reduced the hydrocarbons in ground water significantly since the May 25, 1990 sampling, see Table 1 Using benzene as an indicator, monitoring wells MW1, MW4 , MW5, MW6 , MW7 and MW9 have been reduced to below detection limits while the wells being utilized for vapor extraction (MW2 , MW3 , and MW10) have been reduced by better than 990 MW8 has been reduced by approximately 87'k, since January 12, 1990 Of the newly installed wells MW11 and MW12, MW12 has shown a significant reduction in benzene concentration since the December 22, 1993 sampling of 520 . MW11 has always tested below detection limits . On December 22 , 1993 , a sample of the water being treated by air stripping inside the "ConVault" was obtained for certified laboratory analysis This was accomplished to prove the suitah, 1 7 ty fnr dumni n J tha ?pp ro;�wma�taly 800 gal long . -F ri„ s VL 1..11A cleaned water to the City of Stockton' s sanitary sewer, see Appendix B As of May 25, 1994 an estimated 11897 gallons of gasoline range hydrocarbons have been removed from the soil and ground water beneath this site Previously removed floating product (40 . 25 gallons) , condensation from vapor extraction (48 75 gallons) , pro3ected petroleum hydrocarbon vapor extraction-destruction (73799 pounds/6 . 25 = 11808 gallons) . No chlorinated solvents were detected in chromatogram comparisons, "i e " PAGE 3