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' SECOR L.1 e 1 1 1 t 1* 1 1 1 First Quarter 2003, Quarterly Progress Report April 15, 2003 Page 2 3.0 EVALUATION OF GROUNDWATER EXTRACTION AND SOIL VAPOR EXTRACTION SYSTEMS 31 Introduction GWE and SVE systems were activated on July 3, 2000 A brief description and performance evaluation of the remedial systems during 1003 are presented below Certified analytical reports and chain -of - custody documentation and remedial system operation and maintenance field data sheets are included in Appendices D and E, respectively 3 2 Groundwater Extraction System The GWE system consists of groundwater extraction wells EX -1, EX -2 and EX -3 (Figure 5) These wells are equipped with submersible pumps connected through mechanical piping to a series of granular activated carbon (GAC) vessels prior to an industrial sewer discharge point Chevron discharges treated groundwater at the subject site under City of Lodi wastewater discharge permit #310 To assess effectiveness of the GWE system, process samples were collected bimonthly during this reporting period Sample locations include a Influent port (INFL), prior to the first GAC vessel, between the first and second GAC vessels (MID -1), between the second and third GAC vessels (MID -2), and prior to discharge (EFFL) to the Industrial sewer During these sampling events, INFL, MID -1, MED -2 and EFFL samples were analyzed for TPHg, BTEX, MtBE, TBA, DIPE, EtBE, TAME, ethanol, methanol, EDB and 1,2 -DCA Maximum concentrations of detected constituents are presented below Current and historical analytical information is presented as Table 3 Zone Maximum Constituent Concentrations (µg11) October 8 through December 17, 2002 MtBE TBA EtBE TAME Ethanol Methanol INFL 40 <10 3 <2 <100 <400 MID -1 <2 <10 <2 <2 <100 <400 MID -2 <2 <10 <2 <2 <100 <400 EFFL <2 <10 <2 <2 <100 <400 ExEx laminations < Indicates the constituent was not present at or above the method reporting limit shown Between December 17, 2002 and March 18, 2003, the GWE system discharged a total of 1,080,272 gallons of treated groundwater over a period of 91 days (Table 4) As of March 18, 2003, the GWE system has treated a total of 6,398,966 gallons Calculated discharge rates during the 1Q03 monitoring period ranged from 6 84 to 10 29 gallons per minute (gpm) During 1003 the system extracted an estimated 0 3 pounds of TPHg and 0 2 pounds of MtBE To date, 'the system has extracted approximately 8 7 pounds of TPHg, 0 2 pounds of benzene, and 84 8 pounds of • MtBE Plots of GWE system mass removal trends and influent groundwater TPHg, benzene, and MtBE concentrations versus time are shown on Figure 6 and 7, respectively 1 I IChevron1957751Penodic Monitoring\Quartedy Progress Reports120031ist Quarter -2003 QPR1 REV C doc