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COLLECTION AND ANALYSES OF BACKGROUND WATER AND VAPOR SAMPLES <br /> At least one vapor sample will collected from the vapor extraction system prior to the <br /> startup of air sparging system to establish a background of hydrocarbon levels in the <br /> vadose zone of the trench The vapor sample will be analyzed for concentrations of <br /> TPHg, BTEX, MTBE, and CO2 <br /> Groundwater samples will also be obtained from the temporary well within the trench, <br /> monitor wells MW 1, MW3 and recovery well Rl and analyzed for concentrations of <br /> TPH-G, BTEX, MTBE, dissolved oxygen, and the electron acceptors including nitrates, <br /> sulfates, and ferrous iron <br /> AIR SPARGING <br /> Filtered, oil free compressed air will be infected into the slotted tubing at the base of the <br /> trench at a rate of 1-2 cfm using a dedicated electric pump Air sparging will proceed for <br /> a period of one-two months During the sparging period, the groundwater in the trench, <br /> at monitor wells MW1, MW3 and recovery well Rlwill be sampled periodically for <br /> concentrations of TPH-G, BTEX, MTBE, dissolved oxygen, and the electron acceptors <br /> nitrates, sulfates, and ferrous iron Also during the sparging period, vapor samples will be <br /> b collected from the vapor extraction system and analyzed for concentrations of TPH-G, <br /> BTEX, MTBE, and CO2 <br /> VAPOR EXTRACTION PILOT TEST <br /> A vapor extraction pilot test will be conducted at the conclusion of the one-two month air <br /> sparging period using the VE system described in the sections above The pilot test will <br /> be conducted for 5 days or until breakthrough of hydrocarbons have occurred between <br /> the third and fourth carbon canisters <br /> At startup, the VE system will be adjusted and allowed to run with steady parameters for <br /> one hour The values for the following parameters will then be recorded <br /> 1 Well influent vapor temperature <br /> 2 Well vacuum <br /> 3 Differential pressure, across flow meter, total influent <br /> 4 Stack Temperature, exit <br /> 5 Stack Pressure, 1 foot below exit <br /> 6 Hydrocarbon concentration of the influent as determined by a PID Hydrocarbon <br /> Vapor meter <br /> 7 Hydrocarbon concentration between each carbon and the effluent as determined by an <br /> PID Hydrocarbon Vapor meter <br /> S Lower Explosion Limit (LEL) and Oxygen level with LEL/02 meter <br /> 9 Influent Carbon Dioxide concentration <br /> 10 <br />