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SVE Si stem Installation and Efficiency Report Canepa s Car Wash(Pacific Avenue) June 25, 1999 ' 6 3 SYSTEM ANALYSES Page -S 6 3 1 field Analyses IThe efficiency of the SVE system is estimated based on the laboratory analyses of the air samples collected at the start up of the system on March 15, 1999 and subsequent PID measurements Conversion factors were applied to subsequent field data to calibrate the PID measurements to the initial Iaboratory analyticaf results and are utilized only as estimates based on the initial (March 15, 1999) laboratory analytical results The laboratory analytical results for the air samples collected on March 15, 1999 ' indicate that total BTEX vapors were detected in the air sample collected from the influent and effluent at a concentrations of 2 1 and <0 05 mg/l, respectively The corresponding PID measurements were 281 and 1 9 ppm ILaboratory analytical results of the air samples collected on March 15, 1999 indicate a VOC destruction efficiency ranging froin 98 90 to 99 79 % PID measurements of the VOC concentrations in the influent and effluent collected between March 15 and May 27, 1999, indicate an average VOC destruction efficiency of 99 46% Based on periodic monitoring of VOC concentrations measured with a PID at the system inlet, and the estimated relationship between the field data and the laboratory analytical data, Hydrocarbon removal rates have ianged from approximately 18 58 lbs/day on March 19, 1999 to 131 57 lbs/day on May 4, 1999 Using the conversion factor obtained from the laboratory analytical data and corresponding PID measurements collected on March 19, 1999, it is estimated that a total of approximately 3,085 lbs of Hydrocarbons have been extracted from the subsurface and destroyed as of May 31, 1999 The estimated VOC emission rates range from 0 10 to 0 76 lbs/day which is below the 2 lbs/day stipulated in the ATC Refer to the SXE System Log included in Appendix D 6 3.2 Radius of Influence Vacuum measurements recorded on March 17, 18, and 19, 1999 for the extraction wells indicate the radius of influence at perimeter wells SVE 1, 2, 3, 7, 8, and 9 is greater than 20 feet because cumulative vacuum recorded 20 feet away at idle wells SVE 4, 5, and 6 was 1 4 to 1 7 inches of water By arguments of symmetry, somewhat more than half of this vacuum is additive from surrounding vacuum ' wells Therefore, assuming relatively homogeneous geologic material, a measurable vacuum of approximately 0 7 inches of water or less would be expected 20 feet beyond the perimeter of the SVE well atray The radius of influence or capture is defined as the distance where 0 1 inches of water vacuunn occurs (Pederson and Curtis, 1991, Soil Vapor Extraction Technology Reference Handbook, EPA/540/2-91/003) Based on previous estimates of the extent of gasoline contamination at the site, the limited data collected fiom March 15, 1999 through May 31, 1999 indicate the radius of influence of the SVE system appears to encompass the majority of the gasoline plume within the vadose zone Figure 5, Appendix A, illustrates the estinnatc.d radius of influence aiound the SVE well array 7 0 CONCLUSIONS The SVE system is currently opeiating within the specaf ted requirements established by the SJVUAPCD The folio-%,k ing has been concluded regarding-, the efficiency and operation of the SVE system • The vacuum pressure exerted at the extraction wells is sufficient to extract petroleum hydrocarbon vapors from the subsurface, I • The thernial oxidation unit is maintaining 95% destiuction efficiency or -1 eater LJ CONDOR