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CVV2/0 . A S S O C I A T E S I N C measured in MW3, more than 90 feet east of VE-1 Concentrations of TPHg in the extracted vapors ranged from 35,000 ug/L to 56,000 ug/L ' Convertin these values to arts per million volume (ppmv), concentrations ranged from 9,800 Converting P P PP g ppmv (at 6 hours) to 15,680 ppmv (at 12 hours) Generally, a vacuum of 0 10 is required to ' successfully volatilize subsurface hydrocarbons The effective radius of influence at the site was estimated to be approximately 37 feet ' Dissolved oxygen and groundwater depth data collected during the pilot study indicated that IAS, combined with SVE should provide a viable alternative for remediation of impacted ' groundwater at the site Dissolved oxygen in groundwater was measured in the IAS observation wells at several ' intervals throughout the IAS test In ASO-1, dissolved oxygen ranged from 84 1% to 87 4%, in ASO-2, dissolved oxygen ranged from 16 0% to 32 9%, dissolved oxygen was measured at 62 4% in ASO-3 It appears that the effective radius of influence for the air sparging wells on ' site may be as great as 20 to 30 feet Based on the results of the pilot testing, GAS concluded in their Final Remediation Plan that Mthe cleanup time for remediating the site would be approximately 2 years Remediation Well Installation ' On April 19, 1997, AGE installed one additional SVE well, VW-7 at the eastern edge of the site to a depth of 15 feet Also six IAS points were installed using two 21-inch long, 318-inch t I D stainless steel screen implants attached to an anchor tip at 30 feet bgs IAS-2 through IAS-7 were installed to depths of 30 feet bgs Vinyl tubing (318-inch O D ) was extended from the spargmg screen implant to the surface and a filter pack (fine glass beads) was ' installed around the screen implant from a depth of 25 to 30 feet bgs Bentonite sand (#8 bentonite) was used to make a 4-foot plug above the filter pack and the wells were grouted to ' surface grade with Portland cement Soil Vapor_Extraction_System Installation ' On March 4, 1997, a King, BucklHasstech (KBH) (90-032) catalytic oxidation unit (SVE unit) was delivered to the site The extraction equipment was placed inside a fenced enclosure near ' the west end of the site On April 1, 1997, the natural gas service to the SVE unit an the site was upgraded to 5 pounds of pressure per square inch, the minimum pressure required to operate the KBH catalytic oxidation system ' The existing network at the site consisted of subsurface flex piping from wells VE-2, VE-5, VE-6 and MW4 to the remediation unit enclosure AGE installed additional subsurface piping from wells VE-1, VW-I and VW-7 The piping was then routed through a moisture knockout w 1271421reportslclosore doc 7