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LFR 0 ARCAD I Scompany SVE Pilot Test Stepped-Rate Test The vacuum step tests are designed to test the range of vacuum that can be imposed on the unsaturated zone through the individual extraction well and to observe the resultant vapor flow rates. The flow versus vacuum data yielded from this stepped-rate test will be used to select the optimum vacuum to be used in the constant rate test. The step test data will also be useful for the design of the full-scale SVE system. Well EX-1 will serve as the test/extraction well. If a measurable flow cannot be induced in this well, then the step test will be conducted using well EX-2 as the extraction well. The step test will begin with a vacuum of approximately 20 inches of water column applied at the extraction well. Vacuum will be increased in a series of roughly equal vacuum increments by adjusting the dilution valve. Each subsequent step will be taken only when extraction rates and vacuum remain stable for two sequential readings obtained at least five minutes apart. The step sequence will be continued until the operational capacity of the blower is maximized. Field VOC monitoring (using Tedlar bags and a handheld photoionization detector [PID] or organic vapor analyzer) will be conducted frequently during the early portion of each step in the vacuum step tests to establish an adequate data set of VOC removal rates under changing SVE conditions. VOC data collected early in each step are useful in understanding the rate-limiting processes controlling VOC volatilization. Laboratory samples will be collected from each of the vapor monitoring wells before the start of the test to establish baseline contaminant levels. Constant Rate Test A constant rate test will be performed once the step test is completed and an optimum flow/vacuum combination is determined. The goals of the constant rate test are as follows: • To determine the long-term equilibrium pressure distribution during SVE and to estimate the area of influence for each extraction well • To collect adequate data to allow for the calculation of average air permeabilities • To monitor the changes in VOC concentrations over time to assist in the prediction of the sustained mass removal rates for design and sizing of emission controls components • To evaluate the potential for a SVETS to reduce the concentrations of PCE in soil gas beneath the Site Extraction well EX-1 (or well EX-2 if flow cannot be induced at well EX-1) will be tested at the highest flow rate obtainable during the step test. The constant rate test will be conducted for approximately five days. It is possible that equilibrium may be reached within a few hours of .p-CS-SVE-May09-09366.doc:deh 6