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41 <br /> David Wang, P.E. , Chief <br /> Page 2 <br /> `larch ls, _oql <br /> The criteria considered for the IRM are: <br /> o The off-site control of TCE contaminated ground water froTi the <br /> central area. <br /> o Treatment of TCE to the maximum contaminant level of 5 <br /> micrograms per liter. <br /> o Consistency with the final remedial action for DDRW Sharpe. <br /> Sixty-one technologies were initially screened, including the no <br /> action response. Through several screenings, they were reduc d to <br /> five plausible technologies. They are: <br /> 1) air stripping <br /> 2) carbon adsorption <br /> 3) ozone and ultra violet (UV) light <br /> 4) biological towers <br /> 5) no action (monitoring only) <br /> These technologies were evaluated for: short-term effectiveness, <br /> long-term effectiveness, reduction of contamination, <br /> implementability, cost, protection of human health and the <br /> environment, compliance with applicable and relevant or appropriate <br /> regulations (ARARs) , state acceptance, and community acceptance. <br /> Extraction systems, disposal systems, and the associated p ping <br /> were considered to be similar for any technology chosen. As uch, <br /> these items were not a significant factor in the selection pro ess. <br /> FINAL SELECTION: <br /> The FFS recommended air stripping as the best available technology <br /> for meeting the treatment objectives. The system would consist of: <br /> 1) An extraction and collection system for the TCE contaminated <br /> ground water. Consisting of fifteen extraction wells (for the <br /> A, B, and C zones) and the associated piping network. <br /> i <br /> t <br /> 2 ) Two air stripping towers with off-gas control by c rbon <br /> adsorption. <br /> 3) A discharge system is currently planned for the San Jo quin <br /> irrigation canal . However, a final decision was not male in <br /> the FFS. <br />