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CLEARWATER ' G R D U P • Enwronmentul Services 1 transport to a DHS-certified laboratory for analysts The sample was analyzed for concentrations of TPHg, BTEX, and MTBE by EPA Method 826011 by Kiff Analytical in Davis, California Combined GWE/SVE Testing ' On March 13, 2002, Clearwater performed combined GWE/SVE testing on DPW-1 Based on data collected during the GWE step-tests, a pumping rate of 1 75 gpm was required to maintain drawdown to approximately 25 feet bgs in ' DPW-1 before SVE testing began, so that 15 feet of screen was exposed for SVE After initiation of groundwater pumping, an electric blower was connected to the wellhead and used to induce a vacuum for the SVE portion of the test Several steps of applied vacuum starting at 10 inches of water column (in w c) ending at 50 in w c were ' applied to DPW-1 During SVE testing,the pumping rate needed to be increased to 2 1 to 2 2 gpm to maintain water level at 25 feet bgs at a vacuum up to 40 in w c At a vacuum of 50 in w c , the pumping was increased to ' approximately 2 5 gpm to maintain the water level Combined GWE/SVE testing occurred for less than 4 hours During GWE/SVE testing, Clearwater measured the vacuum and air flow rate at the well head of DPW-1, and ' induced vacuum at nearby wells to determine radius of influence(Tables 4 and 5) 1 Extracted air was treated with vapor-phase GAC canisters prior to discharge to the atmosphere The GAC canisters were removed by the provider for appropriate regeneration following the tests ' At the end of each step, a vapor sample was collected in a Tedlar bag A total of 4 air samples were collected from this phase of testing DPWA The vapor samples were labeled, documented on a cham-of-custody form, and stored ' in a dark container for transport to a DHS-certified laboratory for analysis Each vapor sample was analyzed for concentrations of TPHg, BTEX, MTBE by EPA Method 8260B by Kiff Analytical The laboratory analytical report ' and chain-of-custody is included in Appendix C Combined GWE/SVE/AS Testing ' On March 14, 2002, an air sparge test was conducted on air sparge well AS-1 at the same time as GWE and SVE was performed on DPW-1 The sparge test was conducted using a compressor to pressurize well AS-1 until air flow ' was induced through the well screen (screened from 23 to 25 feet below grade) Soil vapor was extracted concurrently from dual—phase extraction DPW-1 in a manner similar to that described above During the air ' sparging test,pressure and air flow into the sparge well were monitored, and vacuums/pressures at observation wells were monitored Data from combined GWE/SVE/AS testing is included in Table 6 The test was completed in steps using different vacuums at DPW-1 An air sample was collected from DPW-1 during sparging and soil vapor ' extraction (INF-SP) and analyzed for concentrations of TPHg, BTEX, and MTBE by EPA Method 8260B by Kiff . Analytical The laboratory analytical report and chain-of-custody is included in Appendix C t ' ZB178C Feas Test Report 5 May 9, 2002