ARCHIVED REPORTS_XR0001975 - Laserfiche WebLink

Home Browse Search

June 15, 1992 kRCQ Service Station No 548. Stockton. California collected. The effluent vapor sample was collected to estimate the destruction efftciencv of the I C. engine. The VET monitoring data are recorded in Table 1 Laboratory Anaivses and Results RESNA initiates a Chain of Custody Record that accompanied the vapor samples to a State-certified laboratory The vapor samples were analyzed at Sequoia Analyticai in Sacramento, California (Hazardous Waste Testing Laboratory Certificate No 1624). for total petroleum nvdrocarbons as gasoline (TPHg) and benzene. toluene, ethvlbenzene. and total xylene isomers using modified Environmental Protection Agency Methods 8015 and 8020, respectiveiv The results of the laboratory analyses are recorded in Table 1. Copies of the Chain of Custody Records and laboratory reports are attached. Dunng the VET. the highest observed vacuum was 0 31 inches of water from observauon well VW-1 while extraction well VW-3 was undergoing an air flowrate of 74 cfm and a vacuum of 63 inches of water Wells VW-1 and VW-3 are approximateiv 28 feet apart.- Results of laboratory anaivses of vapor samples collected from wells VW-1. VW-2, and VW- 3 indicated that influent TPHg concentrations ranged from 21.000 to 87,000 milligrams per cubic meter. The analytical results of the I C engine effluent vapor sample indicates that the I C engine teas a destruction efficiency of approximateiv 95 percent CONCLUSIONS Utilizing the vacuum and distance measurements obtained during the VST, an effecuve radius of influence can be estimated for the site. The effective radius of influence is defined as the radial distance from a vapor-extraction well within which recorded vacuum levels indicate that suosurface air flowrates are sufficient for remediation. RESNA estimates that a wellhead #Tow rate of 80 cfm will result in an effective radius of influence of approximately 30 feet for one N apor-extraction well (Plate 2). Based on previous investigations (RESNA, Report No 30004-5, report in preparation), the limits of soil containing hydrocarbons extend vertically from approximateiv 30 to 45 feet below surface trade and extends laterally to the north, east and slightly south of the extsung tanks, as shown on Plate 2 RESNA estimates that extraction from the three existing vapor- extraction wells will allow for the removal of hydrocarbons from the described zone. RESNA proposes using a thermal or catalytic oxidizer to extract and treat the gasoline hydrocarbons from beneath the site 04t3ccar 30004-5 2