FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

1 26 January 2007 AGE-NC Project No. 01-0839 Page 8 of 12 2.5 HP motor and electricity was supplied by a gasoline-powered generator. The extracted ' hydrocarbon vapor was routed through four 500-pound (lb) carbon vessels loaded on a trailer. Effluent air from the vessels was monitored with an OVA equipped with a PID to ensure complete ' adsorption of hydrocarbon vapors. The pilot test was initiated at 0755 hr and continued for approximately 8 hours, at which time the ' test was terminated. An induced vacuum potential was applied to the casing of vapor well VW-2. The vacuum-induced pressure reduction was monitored at surrounding observation points(shallow vapor extraction wells VW-4 and VW-5 and deep-screened vapor wells VW-1,V W-3, and VW-6) ' with air-tight well caps fitted to each observation well.A sample port was tapped into the PVC near the extraction well head and a portable OVA equipped with a PID was used to measure influent organic vapor concentrations.The organic vapor concentrations,the induced vacuum potential at the ' observation points(measured utilizing a Magnehelic vacuum guage),and the extracted soil gas flow rate were measured at 0.25-hour or 0.5-hour intervals for the first two hours and at 1-hour intervals for the remainder of the pilot test. The pilot test data are summarized in Table 3. 1 6.1.1. Shallow SVE Pilot Test Sampling and Analysis ' A total of six soil vapor samples were collected during the pilot test. Vapor samples were collected at 2-hour intervals beginning at 0815 hr from the sample port at the extraction well VW-2 to measure ' hydrocarbon concentrations in the extracted soil vapor; one sample was collected at 1600 hr from an effluent port at the end of the pilot test.The samples were collected into Tedlar bags,transported in a container under chain of custody to CTEL, and analyzed within 72 hours for the following constituents: ' 9 TPH-g in accordance with EPA Method 8015M; and • BTEX and MTBE by EPA Method 8260B. 6.1.2. Analytical Results of Soil Vapor Samples TPH-g was detected in the influent vapor samples at concentrations ranging from 5,100 µg/1 to 6,500 µg/1.Benzene,toluene,ethylbenzene,and total xylenes were detected in the vapor samples at ' concentrations as high as 12 µg/1 benzene,27 µg/1 toluene, 26 gg/l ethylbenzene, and 160 µg/l total xylenes. MTBE was detected at concentrations ranging from 39 µg/1 to 71 [41. ' TPH-g and BTEX were detected in the effluent vapor sample at concentrations of 300 µg/1 TPH-g, 2.2 µg/1 benzene, 5.4 µg/1 toluene, 3.1 µg/1 ethylbenzene, and 11 µg/1 xylenes. ' Advanced GeoEnvironmental,Inc. 1