ARCHIVED REPORTS_XR0008922 - Laserfiche WebLink

Home Browse Search

I ' 19 December 2005 • AGE-NC Project No 99-0645 ' Page 5 of 8 ' 26 SVE REMEDIATION FEASIBILITY PROCEDURES Two separate soil vapor extraction pilot tests were conducted on 18 September and 06 October 2003 ' On 18 September 2003, the upper sand layer was tested using vapor well V W 1 B, screened from 15 feet to 40 feet bsg, as the extraction well On 06 October 2003, a second pilot test was conducted on the fine-grained, deeper-impacted areas closest to ground water at the site using vapor well ' V W 1 A, screened from 40 feet to 70 feet bsg as the extraction well The pilot tests were initiated at 0800 and continued for 8 hours A total of four soil vapor samples were collected during each pilot test IAnalytical results of soil vapor samples were generally highest in the second sample collected on 18 September Extraction well V W 1 B results indicated TPH-g was detected in all the soil vapor samples at concentrations ranging from 11,000 µg/l to 14,000 µg/l, BTEX was detected in every sample at concentrations as high as 54 µg/l benzene, 1,400 �tg/l toluene, 160 µg11 ethylbenzene, 990 µg/1 xylenes, MTBE was detected in all samples at concentrations ranging from 730 �Ig/l to ' 860 µg11 Toluene and total xylenes were detected in one sample collected from V W 1 A on 06 October 2003 at a concentration of 0 39 µg/l and 0 29[tg/l, respectively . The shallow test results indicated that the flow rate was initially measured at 42 standard cubic feet per minute(cfm)and the maximum observed was 75 cfm Organic vapor(OV)readings ranged from 923 parts per million (ppm) to 1,100 ppm Induced vacuum measured at extraction well VW 1 B ranged from 20 to 32 inches of water On 06 October 2003,the lower screened vapor extraction test results had measured flow rates between 25 cfm and 31 cfm, a much lower flow than observed in V W 1 B OV readings ranged from 1 2 ppm to 2 5 ppm, which was consistent across the pilot test IInduced vacuum measured at the extraction well (VW 1 A)was always greater than 100 iow During the shallow soil vapor extraction pilot test(18 September)the greatest induced vacuum was Imeasured in the observation point nearest the extraction well,at 0 60 inches of water in wells V W2 and V W3 The lowest vacuum was measured in MW-3,approximately 30 feet west of the extraction point and screened much lower in the stratigraphy at the site, however, sufficient induced vacuum was observed in the monitoring wells to demonstrate that a vertical connection may exist across the vertically separated layers at the site During the deeper soil vapor extraction pilot test (06 October 2003), the greatest induced vacuum was measured in the observation point nearest the extraction well, at 0 45 inches of water in well MW-IR The lowest vacuum was measured in VW2 and VW 1B, approximately 20 feet west of the extraction point and screened above the lower stratigraphy at the site Again, sufficient induced vacuum was observed in the monitoring wells and also in the upper soil vapor extraction wells to demonstrate that a vertical connection may exist across the vertically separated layers at the site . AGE plotted on a logarithmic scale the maximum vacuum measured at the observation points during Advanced GcoEnvironmentai,Inc