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L F R ARCADIS .papy <br /> Vapor Flow Monitoring <br /> The vapor flow rate of the extraction system will be monitored with a Pitot tube and differential <br /> pressure gauge installed in the conveyance piping where it exits from the extraction well. The Pitot <br /> tube measures a pressure differential between a small-diameter tube pointed into the vapor stream <br /> within the conveyance pipe and the ambient pressure. The pressure differential between the two <br /> points, the diameter of the pipe, and the temperature of the vapor are used to calculate the flow <br /> rate for the vapor stream. <br /> Field Monitoring Samples <br /> Screening level samples will be collected from the SVE wells before, during, and after each SVE <br /> test sequence. Samples will be collected in 1-liter Tedlar bags for total VOC monitoring using a <br /> field PID. Samples will be collected using a vacuum pump connected to a vacuum chamber <br /> housing the Tedlar bag. The Tedlar bag will be connected to the SVE well sampling port using <br /> inert Teflon tubing that passes through the wall of the vacuum chamber. To retrieve a vapor sample <br /> under vacuum and overcome the vacuum in the extraction well or monitoring well, a small vacuum <br /> pump will be connected to the chamber and a vacuum developed. When the vacuum in the chamber <br /> exceeds the vacuum in the well, soil vapor will flow from the well into the Tedlar bag contained in <br /> the chamber. Once filled, the Tedlar bag will be connected to a calibrated PID and a total VOC <br /> measurement will be made. <br /> Soil-Vapor Laboratory Sample Collection <br /> Vapor samples will be collected for laboratory analysis at the extraction well and selected <br /> monitoring wells. One sample will be collected from each soil-vapor monitoring well prior to the <br /> start of the test and near the end of the extraction period. Stagnant air inside the monitoring points <br /> will be purged prior to sample collection. Samples for laboratory analysis will be collected in <br /> clean, I-liter Summa'canisters provided by the selected laboratory. To collect a sample, the <br /> Summa'canister will be attached by new silicon tubing to a hose barb on the wellhead. Air will be <br /> drawn through the tubing into the canister. A valve mounted on the canister's orifice will then be <br /> closed and the canister will be shipped to the laboratory under standard chain-of-custody <br /> procedures. Samples will be analyzed for halogenated VOCs using EPA Method TO-14 by a <br /> California-certified analytical laboratory. <br /> SVE Data Analysis, Reporting, and Schedule <br /> Data collected during the SVE pilot test will be evaluated and used to develop the necessary design <br /> parameters for an SVE system. It is anticipated that the following analyses will be performed: <br /> • tabulations and plots of air flow versus extraction pressures to assist in sizing and specifying <br /> SVE blowers and piping <br /> wp-CS-SVE-May09-09366.doadeh 9 <br />