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MAR-30-2000 16 36 CAMBRIA 510 420 3170 P 03/10 The conceptual design for remediation of the site was developed in 1993 (Geraghty & Miller, 1993) and included extraction of groundwater and soil vapor from multiple dual-purpose • extraction wells Groundwater is collected through a piping network and pumped to a central plant for treatment. The objective of groundwater extraction at the site is source control and hydraulic containment In the future, treated, oxygenated water may be re-injected into areas with localized contamination to enhance msitu biodegradation and flushing/removal of contaminants The design basis for the treatment system capacity was based on contaminant transport modeling performed as part of the conceptual design effort. Total site design now is 550 gallons per minute (gpm) Concentrations of 1,272 ugll benzene, 143 ugA toluene, 108 ugll ethyl benzene, 404 ug1l total xylenes, and 600 ugA MTBE were indicated. Minor concentrations of chlorinated solvents also exist at the site at levels above drinking water standards; 7.6 ugll tetrachloroethene (PCE) and 42 ugll trichloroethene (TCE) were anticipated for the influent stream After the initial treatment system began operations, the MTBE concentration in four of the wells increased to 4,000 ugA This Increase in MTBE concentration exceeded the designed treatment system capacity A pretreatment process of the four wells to reduce MTBE concentrations before entering the designed treatment system was examined Several technologies were examined to reduce MTBE An advanced oxidation system (HROx) provided by Applied had several apparent advantages over conventional air stripping These advantages included, lower operating and maintenance costs due to a lack of air stream treatment and stripper fouling, a relatively compact size, a stable destructive (non-transfer) • process, and the effective removal of MTBE "Applied" has extensive experience in the remediation of MTBE in ground water using their HiPOx technology To properly evaluate HiPOx technology for the Nevada site, Applied deployed a self-contained, mobile Pilot System that was driven to the Nevada location for a demonstration test The HiPOx Pilot System is mounted inside of a 14-foot van and has a capacity to treat 3-10 GPM of contaminated water The HiPOx Pilot System is equipped with ozone generators, mixers, and multiple injector ports for ozone and hydrogen peroxide, The HiPOx Pilot System is designed to allow collection of all data necessary to design full-scale HiPOx treatment system for a specific site HiPOx PROCESS DESCRIPTION The HiPOx process developed by Applied is an Advanced Oxidation process (AOP) that uses ozone (03) and hydrogen peroxide (H202) to destroy organic compounds Ozone dissociates as well as reacts with hydrogen peroxide to produce an intermediate, hydroxyl radical (-OH) Hydroxyl radicals are the second most powerful oxidizing agent found in nature, These hydroxyl radicals react very rapidly to oxidize organic contaminants to non-hazardous compounds carbon dioxide and water The oxidation of the organic contaminants does not • t W G3aze and J Ksr+g,J Amer WaferWW*$A=C.80,51 (1988) Page 2