Laserfiche WebLink
I <br /> CLEARWATER <br /> . G R O U P, I N C <br /> 5.2 Soil Vapor Extraction p System Monitoring <br /> Table 2 presents data derived from measurements of air flow, vacuum, and FID <br /> readings taken at the wellheads, as well as total system influent and effluent FID <br /> measurements (where applicable). Equivalent hexane concentrations are included <br /> because the FID equipment is calibrated to methane Flow rates are reported in <br /> standard cfixn (scfm) because the field monitoring equipment used automatically <br /> converts the actual cfm (acfm) to scfm <br /> Air samples were collected In clean Tedlar bags, labeled and documented on a chain- <br /> of-custody form All samples were analyzed by a state-certified laboratory. The <br /> samples collected on July 11, 1995, were analyzed by Trace Analysis Laboratory, Inc <br /> in Hayward, California All air samples were analyzed for TPHg by EPA 8015 (DHS- <br /> modified) and BTEX by EPA 8020 (modified) Data are presented in Table 3 and <br /> Appendix B <br />' 5.3 Soil Vapor Extraction System Results <br /> FID, flow and vacuum measurements are summarized In Table 2. Table 3 <br /> summarizes analytical data from Tedlar bag vapor samples. A copy of the laboratory <br /> results and the chain-of-custody forms are included in Appendix B <br />' The following is a summary of the system operating parameters <br /> • Flow rates at the five wellheads ranged from 10 to 53 scfm, total flow was <br />' approximately 154 scfm on July 11, 1995 <br />' • Vacuums at the five wellheads ranged from 2 5 to 5 0 inches water (with all five <br /> wells on-line) <br />' + Analysis of Tedlar bag samples collected on July 11, 1995, indicated that <br /> hydrocarbon vapors were not detected in samples VW-1 and VVIR-3. <br /> Hydrocarbon concentrations In samples from VW-2, VW-4, and VW-5 were 45, <br /> I94, and 280 mg/m3. respectively <br /> • Benzene was not detected m individual well samples or in the effluent sample <br />' An estimate of the cumulative volume of recovered hydrocarbons was calculated <br /> using flow rates and the laboratory analytical results Pertinent assumptions and <br /> equations are presented in Appendix C As of July 11, 1995, an estimated 112 pounds <br /> of hydrocarbons had been removed from the subsurface by the SVE system <br /> Calculations of the recovered hydrocarbons were made on the basis of the following <br />' analytical results. <br />' D-102 1Q95 4 August 31,1995 <br />