WORK PLANS - Laserfiche WebLink

Home Browse Search

L F R an ARCADIS company operation; however, the constant rate test will continue for approximately five days to assess the effectiveness of the long-term vapor extraction in reducing vadose zone PCE concentrations. Equilibration in the monitoring wells is defined as less than 10 percent change between readings for two consecutive measurements taken 15 minutes apart. If the levels do not appear to be equilibrating after several hours of operation, the data will be reviewed and a decision will be made in the field as to whether to continue the test. Field VOC monitoring will be conducted more frequently during the early portion of the constant rate test to establish an adequate data set of VOC removal rates at the beginning and end of the test. A laboratory sample will be collected from the extracted vapor stream at the end of the test. Vacuum responses will also be recorded at each monitoring well, more frequently at the beginning of each test and then decreasing at an approximate logarithmic rate over time because the rate of vacuum response typically decreases with time at a corresponding rate. SVE Test Equipment A variety of extraction and instrumentation equipment will be used to perform the SVE pilot test. The extraction blower, piping, and emissions control equipment will be configured to provide maximum flexibility so that a range of tests can be performed. Major test equipment is described below. Blower Assembly and Emissions Control Because of the temporary nature of the pilot test program, a rental SVE blower assembly will be used. The SVE blower system will consist of a blower capable of providing a range of vacuum and flow rates up to the maximum specified capacity, as described below. The SVE well will be connected to the blower and emissions control equipment using polyvinyl chloride piping and heavy-wall flexible tubing. All conveyance piping will be sized adequately to minimize flow restrictions and pressure losses to the vapor stream. The blower system will include a dilution air inlet for increased operational flexibility. Two vapor-phase carbon scrubbers will be used to remove PCE from the effluent stream before venting to the atmosphere. Instrumentation and Monitoring The parameters that will be measured during the SVE tests include: • air pressure (vacuum) • air flow rate • extracted air temperature • VOC concentration (by PID and laboratory analysis) wpCS-SVE-May09-09366.doc:deh 7