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S E C O R First Quarter 2003, Quarterly Progress Report April 15, 2003 Page 3 3 3 Soil Vapor Extraction System The SVE system is comprised of four vapor wells (VE -1 through VE -4), connected by mechanical piping to a 5 horsepower (hp) positive -displacement blower, and a catalytic oxidizer Vapors from the sod are removed under vacuum by the blower and petroleum hydrocarbons in these vapors are destroyed by a catalytic oxidizer, prior to discharging the air stream to the atmosphere The San Joaquin Valley Air Pollution Control District (SJVAPCD) permits the operation of the SVE system under permit No N-4343- 1.0 To assess the effectiveness of the SVE system, process samples were collected monthly from the vapor stream before (INFL) and after (EFFL) the catalytic oxidizer Each sample was analyzed for TPHg, BTEX, and MtBE Maximum constituent concentrations are presented below During the 1003 the SVE system was approximately 60% operable System down time was attributed to a mechanical failure of the vapor extraction blower and the resultant time necessary to make repairs Tables 5 and 6 present operational measurements and calculated mass removal rates for TPHg, benzene, and MtBE, respectively ' During 1 Q03 the SVE system removed approximately 5 1 pounds of TPHg Although petroleum hydrocarbons were not detected in the influent vapor stream , a concentration of one-half the laboratory detection limit was used to facilitate calculations Since operation began, the SVE system has removed an estimated 4,120 1 pounds of TPHg, 85 7 pounds of benzene, and 443 8 pounds of MtBE Mass rremoval trends and influent soil vapor TPHg, benzene, and MtBE concentrations versus time are shown on Figures 8 and 9, respectively 3.4 Hydrocarbon Mass Estimate The hydrocarbon mass estimates presented below are an update of results presented within the Problem Assessment Report/ Final Remediation Plan (PAR/FRP) Addendum, dated June 5, 2001 Methodology ' for determining the mass of hydrocarbons adsorbed to sod and dissolved in groundwater can be found within the PAR/FRP Addendum ' 34.1 Estimated Mass of Petroleum Hydrocarbons Dissolved In Groundwater The results presented below are based on the calculation presented within the PAR/FRP Addendum and cumulative 1003 GWE mass removal data To conservatively estimate analyte mass remaining, ' historical groundwater analytical data was used This information is summarized In the following table I 11Chevron1957751Penodic MonitoringlQuarterly Progress Reports1200311s1 Quarter -2063 QPR1 REV C doc G Maximum Constituent Concentration (ppmV) SAMPLING December 17, 2002 through March 18, 2003 LOCATION TPHg Benzene Toluene Ethyl -benzene Xylenes MtBE INFL <5 0 <0 050 <0 050 <0 050 0 59 <0 10 EFFL <5 0 <0 050 <0 050 <0 050 <0 050 <0 10 Explanations 7:1 ppmV = Parts per million by volume < Indicates the constituent was not present at or above the method reporting limit shown During the 1003 the SVE system was approximately 60% operable System down time was attributed to a mechanical failure of the vapor extraction blower and the resultant time necessary to make repairs Tables 5 and 6 present operational measurements and calculated mass removal rates for TPHg, benzene, and MtBE, respectively ' During 1 Q03 the SVE system removed approximately 5 1 pounds of TPHg Although petroleum hydrocarbons were not detected in the influent vapor stream , a concentration of one-half the laboratory detection limit was used to facilitate calculations Since operation began, the SVE system has removed an estimated 4,120 1 pounds of TPHg, 85 7 pounds of benzene, and 443 8 pounds of MtBE Mass rremoval trends and influent soil vapor TPHg, benzene, and MtBE concentrations versus time are shown on Figures 8 and 9, respectively 3.4 Hydrocarbon Mass Estimate The hydrocarbon mass estimates presented below are an update of results presented within the Problem Assessment Report/ Final Remediation Plan (PAR/FRP) Addendum, dated June 5, 2001 Methodology ' for determining the mass of hydrocarbons adsorbed to sod and dissolved in groundwater can be found within the PAR/FRP Addendum ' 34.1 Estimated Mass of Petroleum Hydrocarbons Dissolved In Groundwater The results presented below are based on the calculation presented within the PAR/FRP Addendum and cumulative 1003 GWE mass removal data To conservatively estimate analyte mass remaining, ' historical groundwater analytical data was used This information is summarized In the following table I 11Chevron1957751Penodic MonitoringlQuarterly Progress Reports1200311s1 Quarter -2063 QPR1 REV C doc G