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_> San Joaquin County EHD September 5, 2008 Page 5 of 10 the air sparging portion of the pilot test. Table 4 summarizes the construction details of the wells proposed in this workplan. V&W will advance the borings using a drilling rig equipped with eight-inch diameter hollow stem augers. The observation wells will be completed using 2-inch diameter schedule 40 PVC blank casing from surface to the screened interval. OW and OW2 will use 10 feet of 0.020-inch slotted screen set from 15 to 25 feet bgs. OW3 will use 20 feet of 0.020-inch slotted screen set from 40 to 60 feet bgs. A filter pack consisting of No. 3 sand will be emplaced from total depth to two feet above the top of each screened interval. In each well the remaining annulus will be completed with two feet of hydrated bentonite pellets overlain by neat cement grout to the ground surface. The well tops will be fitted with locking caps and covered with traffic rated well boxes. OW3 will be developed no sooner than 48 hours after installation. An observation well diagram is included as Figure 6. Pilot Test Ground Zero personnel will supervise the pilot test activities to be conducted by Del-Tech Geotechnical Support Services, Inc. of, Oakdale, California (Del-Tech). Del-Tech provides a turnkey service on vapor extraction pilot tests. Del-Tech will mobilize to the Site with an internal combustion unit (IC) capable of pulling a vacuum greater than 75 inches of water column and achieving flow rates up to 110 cfm and an air compressor capable of supplying continuous air at up to 100 pounds per square inch gas (psig) and reaching flow rates of 50 cubic feet per minute (cfin or ft3/min). I Vapor Extraction The soil vapor extraction pilot test will utilize an IC engine, equipped with a catalytic converter, to induce a vacuum on each VEW, independently, for a period of up to three hours. Table 1 . summarizes the wells to be used to observe SVE influence while using VEW1 as an extraction well. Table 2 summarizes the wells to be used to observe SVE influence while using VEW2 as an extraction well. Applied vacuum and flow rate will be measured as will vacuum in the observation wells every 30 minutes during each test. Extracted vapor concentrations for each well will be measured periodically with a PID. Two influent vapor samples per well, one after approximately 15 minutes of operation and one at completion of each test will be collected in Tedlar® bags to analyze the extracted vapor for contaminant concentrations. Soil vapor samples will be submitted to Air Toxics Limited of Folsom, California for analysis of TPHg, BTEX f compounds and MTBE by EPA Method TO-3. GAGROUNDMHARRYS AUTO\Reports\Workplans\wp sve pilot test.doc I