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Corrective Action Plan <br /> Montgomery Ward Auto Service Center, Stockton, CA <br />' Air Sparging <br /> Air sparging is an innovative and relatively new method of ground water treatment in <br /> which pressurized air is iiilected below the ground water table The resultant air-water <br />' interface formed by air bubbles cause volatile chemicals to be transferred into the gaseous <br /> phase and is brought up into the vadose zone by the buoyant air bubbles The vapors can <br /> then be extracted from the vadose zone and treated using soil vapor extraction technology <br /> ■ <br /> Probability of Achieving Cleanup Goals <br /> The current understanding on the effectiveness of air sparging is that it lowers <br />' contaminant concentration very quickly, particularly if the contaminants are <br /> volatile Therefore, air sparging is known to be able to reduce volatile <br /> contaminants in ground water rather quickly The only problem is that the <br />' influence of air sparging wells is restricted to a certain distance (e g , 20 to 50 feet <br /> around the sparging well) Thus, at sites with Iarge plumes, multiple sparging <br /> wells are needed Therefore, probability of achieving cleanup goals using this <br /> method is moderately good and consequently, a grade of 7 was assigned to this <br />' criteria for this remedial alternative <br /> e Ease of Implementation <br /> Air sparging wells already have been installed at one of the source areas, i e , near <br /> the former USTs Therefore, the only additional work required will be the <br /> installation of additional sparing wells, and the underground piping required to <br /> connect the wells to a compressor These steps will not significantly impact on-site <br /> operations Therefore, ease of implementation for this method is very favorable <br /> Thus, a grade of S was assigned to this criteria for this remedial alternative <br />' a Availability of Space <br />' The only aboveground space required for this method is an area to locate an air <br /> compressor All other appurtenances are below ground Therefore, space is not a <br /> problem and is an advantage to this method Thus, a grade of 10 was assigned to <br />' this criteria for this remedial alternative <br /> E Disruption to Facility Operations <br />' As in the case of soil vapor extraction, implementation of this method is not <br /> expected to pose any significant disruption to operations Thus, a grade of 9 was <br /> assigned to this criteria for this remedial alternative <br /> e Time of Completion <br /> It is difficult to estimate the exact time needed for achieving ground water cleanup <br />' goals using air-sparging However, past experience suggests that air-sparging is <br /> usually a fast and effective method and will probably achieve cleanup goals (in the <br /> +hi to two Ti,,,o -me of coirnletion is neither a hia <br /> JViiilG area' W1U111i oliL Lv LW V year) lliuu, tour.. -1 t .. .� <br />' advantage nor a big disadvantage of this method Therefore, a grade of 5 was <br /> assigned to this criteria for this remedial alternative <br /> Project No 1232 <br />' SAB WORD 1232CAP <br />