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<br /> A S S O C I A T E S I N C
<br /> Analytical results of groundwater samples are summarized in Table 2 Laboratory data sheets and
<br /> chain-of-custody documentation for groundwater samples are contained in Appendix D
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<br /> 5.0 VAPOR EXTRACTION PII,OT TEST
<br /> ' A vapor extraction pilot test was proposed in ATC's Workplan for Soil Vapor Extraction and
<br /> Additional Investigation at Diesel Performance, 2804 E Fremont Street, Stockton, California,
<br /> dated August 14, 2001 The purpose of this test was to evaluate vapor extraction as a viable
<br /> remedial option for impacted soil and groundwater at the site and to collect data to design a vapor
<br /> extraction system
<br /> 5_1 Vapor Extraction Test Methods and Procedures
<br /> ' On December 10 and 11, 2001, ATC performed a short-term vapor extraction test and a long-
<br /> term vapor extraction test On the first day, a short-term vapor extraction test was performed by
<br /> ATC using vapor well VW1 as the vapor extraction point while monitoring vacuum response in
<br /> the surrounding wells, MW 1, MW2, MW3, MW4, VW 1, and VW3 (Figure 2) The test was
<br /> approximately 2 hours in length Flowrates, applied vacuums, influent and effluent VOC
<br /> concentrations, and temperatures were also monitored during the test Vapors were extracted
<br /> using an internal combustion (IC) engine equipped with a 5-hp blower and a moisture knockout
<br /> chamber Two influent vapor samples were collected during the test, one after 15 minutes of
<br /> operation and one after 2 0 hours of operation An effluent vapor sample was collected after 15
<br /> ' minutes of operation Samples were submitted under chain-of-custody to Sequoia Analytical
<br /> (FLAP #1624) and analyzed for TPHg by EPA method 8015, BTEX by EPA method 8020, and
<br /> MTBE, 1,2-DCA, EDB, ETBE, DIPE, TBA, and TAME by EPA Method 8260
<br /> ' On the second day, a long-term vapor extraction test was performed by ATC using vapor well
<br /> VW3 as the vapor extraction point while monitoring vacuum response in the surrounding wells,
<br /> MW 1, MW2, MW3, MW4, VW 1, and VW2 (Figure 2) The test was approximately 4 hours in
<br /> length Flowrates, applied vacuums, influent and effluent VOC concentrations, and temperatures
<br /> I were also monitored during the test Vapors were extracted using an internal combustion (IC)
<br /> engine equipped with a 5-hp blower and a moisture knockout chamber Two influent vapor
<br /> samples were collected during the test, one after 15 minutes of operation and one after 3 75 hours
<br /> of operation An effluent vapor sample was collected after 15 nunutes of operation Samples
<br /> were submitted under chain-of-custody to Sequoia Analytical (FLAP #1624) and analyzed for
<br /> TPHg by EPA method 8015, BTEX by EPA method 8020, and MTBE, 1,2-DCA, EDB, ETBE,
<br /> DIPE, TBA, and TAME by EPA Method 8260 —
<br /> 5_2 Vapor Extraction Test Results
<br /> Results and field readings from the short-term and long-term vapor extraction tests performed on
<br /> December 10 and 11, 2001 are summarized in Tables 5 and 6 Copies of field notes are contained
<br /> in Appendix E Copies of laboratory reports are contained in Appendix F
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