ARCHIVED REPORTS_XR0008558 - Laserfiche WebLink

Home Browse Search

/ SOIL VAPOR EXTRACTION PILOT TEST The purpose of the soil vapor extraction (SVE) pilot test is to collect data necessary to evaluate the performance and determine the effectiveness of, and design parameters for, an SVE system. The procedures for conducting the pilot test, as well as the data to be collected dung the test, are described below. The SVE pilot test is a 4 to $ hour test conducted on-site at one specific location. The procedure tests one well while monitoring surrounding wells for a change in pressure. The data collected during the test will allow Brown and Caldwell design engineers to determine the applicability of SVE at the site as well as provide the specific data required for design of a SVE remediation system. Primary equipment used during the pilot test will consist of a portable vacuum pump powered by a 5-horsepower electnc motor and a 40 kilowatt 240-volt portable generator to run the vacuum pump. In addition, flow rate data will be collected during the test using a pitot tube magnehelic type flow meter and vacuum measurements will be collected using a red guage oil manometer or calibrated magnehelic capable of reading vacuum. Emissions from the test will be controlled with granular activated carbon (GAC) consisting of two 55-gallon GAC drums placed in series. A portable photo-ionization detector (PID) will be used to momtor the GAC units for breakthrough. If breakthrough occurs, either a fresh GAC unit will be installed or the test will be terminated A temporary seal will be prepared for the top of the test well The soil/casing interface will be sealed with a bentorutelwater slurry to eliminate air leakage around the casing while flexible hose will be used to connect the well head to the vacuum pump. Vacuum extraction will be started at a low rate and vacuum will be measured with a temporary gage on existing monitoring wells, or other SVe wells, surrounding the test well. After one hour, the rate will be increased and vacuum will be measured again in the monitonng wells. This process will continue until the maximum rate of the equipment is reached. Extraction will continue at the maximum or optimum rate for a maximum of S hours, unless otherwise specified. The total length of the test will depend upon the concentrations of volatile organic constituents (VOCs) being removed, the extraction rate, and whether or not a sparge test is conducted. During the SVE test, total VOC readings will be collected every 15 minutes with a PID to identify the relative concentrations of total VOCs being removed Total VOC concentrations based on PID readings will be plotted versus time. Once the concentration stabilizes, a sparge test could be started. Continued monitoring of VOC concentration would indicate the effectiveness of the sparging. In addition, a maximum of 3 vapor samples will be collected, in 1-liter tedlar bags, from a sample tap located at the outlet of the vacuum pump, at selected times