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r ' S E C U R - Third Quarter 2003, Quarterly Progress Report • October 14, 2003 Page 2 3-0 EVALUATION OF GROUNDWATER EXTRACTION AND SOIL VAPOR EXTRACTION ' SYSTEMS GWE and SVE systems were activated on July 3, 2000 A brief description and performance evaluation of the remedial systems during 3Q03 are presented below Certified laboratory analytical reports and ' chain-of-custody documentation and remedial system operation and maintenance field data sheets are included in Appendices D and E, respectively On August 20, 2003, SVE was discontinued as approved by the Regional Water Quality Control Board (RWQCB) in their letter dated August 18, 2003 A copy of this letter is included in Appendix F 3 1 Groundwater Extraction System ' The GWE system includes 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 (City) wastewater discharge permit #328 To assess effectiveness of the GWE system, process samples were collected monthly 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, MID-2 and EFFL samples were analyzed for TPHg, BTEX, MtBE, TBA, DIPS, EtBE, TAME, ethanol, methanol, EDS and 1,2-DCA Maximum concentrations of detected constituents are presented below Current and historical ' analytical information is presented as Table 3 Maximum Constituent Concentrations (µgll) r ' Zone i MtBE TBA EtBE TAME Ethanol Methanol ' INFL 15 <10 <2 <2 <100 <400 MID-1 <2 <10 <2 <2 <100 <400 1 MID-2 <2 <10 <2 <2 <100 <400 EFFL <2 <10 <2 <2 <100 <400 Explanations- , <Indicates the constituent was not present at or above the method detection limit shown Between June 19 and September 16, 2003, the GWE system discharged a total of 932,565 gallons of ' treated groundwater (Table 4) As of September 16, 2003, the GWE system had treated a total of 7,847,864 gallons Calculated discharge rates during the 3Q03 monitoring period ranged from 5 69 to 7 28 gallons per minute (gpm) ' During 3Q03, the system extracted an estimated 0 3 pounds of TPHg To date, the system has extracted approximately 9 2 pounds of TPHg 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 MonitoringlQ P R1200313rd Quarter-2003 OPP doc