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OR.- I e , ° E2=0 _- 973 and EX were connected to a vacuum system (1HP Rotron Blower) that exhausts into four 65 gallon activated charcoal tub scrubs. Sample ports were installed at each well to obtain samples, and vacuum readings, at the influent of the blower for samples and vacuum monitoring, and at the exhaust of the blower for pressure and sample monitoring. A sample port was also located on the exhaust of the charcoal tub scrubs for samples and pressure monitoring. The exhausts of the tub scrubs were checked on alternate days for breakthrough using a hand held photoionizing detector (PID) that had been calibrated with Isobutylene as 54 ppm benzene in air. Once breakthrough occurred as shown by the PID, a bag sample (tedlar bag) of the charcoal exhaust was obtained and the pilot test was terminated. At the start up of the test, influent samples were obtained from monitor wells P1, P3 .and EX and an effluent sample was obtained from the exhaust of the blower and analyzed for total Petroleum Hydrocarbons (TPF?) as gasoline and diesel along with Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) using DHS headspace method with FID chromatograph Western Geo-Engineers (WEGE) . A leak developed in the blower on December 13, 1990 and the test was shut down until the leak was fixed. The test resumed on December 27, 1990 and effluent *bag sampling along with the PID screen commenced. Bag samples were obtained from the effluent of the pump, along with .vacuum or pressure readings from the wells and pump. PID screening of the charcoal exhaust showed breakthrough occurring on January 4, 1991. At this time an Effluent sample was obtained from the charcoal tub scrub . exhaust prior to shutting the system off and disconnecting it from the r. wells. This sample was analyzed using the DHS headspace method ( for Total Fuel Hydrocarbons and BTEX. A sample of the influent to the charcoal was also obtained and chain of custody delivered to Chemtech Laboratories for analysis using EPA modified 8015 and 602 for TPH and BTEX respectively. This sample was used for the profile for shipment of the charcoal to be regenerated. Throughout the test vacuum readings were obtained from the ground water monitoring wells, to help establish the radius of influence of the vapor extraction system. CALCULATING RESULTS AIR SAMPLES To calculate the pounds (lb) per day the concentration is multiplied by the volume of air produced in one day. The lab reports the Concentrations (C) of the air sampling in ug/liter. The first step is to convert this value to lbs/cf (pounds per cubic foot) . ug/1 x 0.000001g/ug x 0.0022051g/g x 28.321/cf = 0.000000622lb/cf The volume of air produced in one day, equals the flow rate (Q )x the time of flow. V = Q x T = cf/day cf/min x 1440min/day The volume is corrected to standard temperature and pressure (STP) . a