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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 3003 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, 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 WI) MtBE TBA EtBE TAME Ethanol Methanol INFL 15 <10. <2. <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. 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 w 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. I:1Chevron1957751Periodic Monitorinq\Q P R%200313rd Quarter -2003 QPR.doc i r