FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

26 January 2007 AGE-NC Project No. 01-0839 Page 11 of 12 • On 26 December 2006, an 8-hour SVE pilot test was conducted at the site using shallow- screened vapor well VW-2, screened from 15 feet to 30 feet bsg, as the extraction well. The pilot test was initiated at 0755 hr and continued for approximately 8 hours,at which time the test was terminated.The flow rate was measured between 80 and 85 scfm for the 8-hour test. Influent organic vapor readings ranged from 303 ppm to 872 ppm and induced vacuum measured at the extraction well was between 28 and 30 inches of water. ' • Based upon a vacuum of 0.1 inches of water, the projected ROI of shallow SVE at the site will be approximately 62 feet(Figure 3). • TPH-g was detected in the influent vapor samples at concentrations ranging from 5,100 µg/1 to 6,500 µg/l. 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 µg/1 ethylbenzene, ' and 160 µg/1 total xylenes. MTBE was detected at concentrations ranging from 39 µg/1 to 71 µg/1. ' • TPH-g and BTEX were detected in the effluent vapor sample at concentrations of 300 µg/l TPH-g, 2.2 µg/1 benzene, 5.4 µg/l toluene, 3.1 gg/1 ethylbenzene, and 1 I µg/1 xylenes. • On 27 December 2006, an SVE pilot test was conducted at the site using deep-screened vapor well VW-1, screened from 45 feet to 60 feet bsg,as the extraction well. However,the flow rate was unable to be measured on the flow meter, which requires a flow rate greater than 4 scfm to register.Induced vacuum measured at the extraction well was approximately ' 64 inches of water.Wells VW-3 and VW-6 were subsequently tested with similar results and the pilot test was terminated after attempting to draw from all three deep-screened wells.No ' vapor samples were collected. ' 8.0. CONCLUSIONS As set forth in the Additional Site Assessment and Soil Vapor Extraction Pilot Test Work Plan and ' the Additional Site Assessment and Soil Vapor Extraction Pilot Test Work Plan Addendum for the site,performance of the soil vapor extraction tests took place in December 2006 to evaluate SVE as apotential remediation option for petroleum hydrocarbon contamination in soil.Based on the results ' of the feasibility test, AGE concludes that,utilizing the shallow-screened SVE wells,the remedial technique would be successful in mitigating adsorbed contamination in the vadose zone. Based on the results of the CPT investigation,ground water contamination does not appear to extend to depths of 88 feet(grab ground water sample CPTl-88-W)or greater(grab ground water samples CPT2-95-W and CPT2-115-W). ' Advanced GcoEnvironmental.Inc.