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5.0 PROPOSED REMEDIATION PLAN After evaluating the five options suggested in this workplan, JJW is recommending that we proceed with the ozone injection. JJW believes ozone injection is the most cost efficient way to reduce and eliminate the petroleum hydrocarbon contamination in the least amount of time for this site. JJW's experience to date has shown ozone injection to be effective in reducing plume size and ultimately eliminating hydrocarbon contamination. JJW has identified a number of ozone injection systems currently operating in the Stockton area, including at the Crystal Creamery Plant, two Unocal sites, a Chevron Lstation at Highway 4 & Interstate 5, and a 76 Station on March Lane. JJW Geosciences proposes to use a KVA C-SpargerTm ozone injection system. The C- LSpargerTM system uses an ozone generator combined with an air compressor to deliver ozone-laden air downhole into the contaminated aquifer. Ozone is a strong oxidizing agent, and can greatly hasten the rate at which organic compounds (e.g. contaminants) are oxidized (degraded). Since the ozone is delivered in-situ, contaminant extraction and 6' ex-situ discharge concerns need not be addressed, reducing. costs. A bubble-diffusing sparge point is used to generate minuscule air bubbles, thus extending the residence time that the ozone remains in contact with the contaminants: 5.1 Permitting Appropriate permit applications and fees will be obtained from the San Joaquin County Environmental - Health Division (SJCEHD) to conduct 'the services described in this workplan. A site-specific Health and Safety Plan will be prepared for this investigation. 5.2 Installation-of Ozone Injection System JJW is proposing installing a 10-zone Ozone Injection Panel (OIP) utilizing ten sparge points. The ozone sparge points are typically two inch diameter by thirty inch long ' diffusers. The majority of the diffusers will be set fifteen feet below the groundwater is surface. Two of the ten sparge points are expected to be installed at a deeper interval at the same location as two of the shallower points to have a greater impact on the limited, known deeper hydrocarbon contamination. Approximate locations proposed are shown L# on figure 3. Exact placement of the sparge points may vary somewhat due to recommendations from the Ozone System manufacturer,but will correspond to-the known areas of hydrocarbon contamination and the contaminate concentrations and depths in the groundwater. i The sparge points are laid out to give overlapping coverage with an assumed radius of influence of fifteen feet per point. The radius of influence is derived from recommendations of the manufacturer of the ozone injection system and'is based in part on the observed lithology primarily consisting of silt to fine, occasional medium grained sands interbeded with permeable silty clay zones. To install the sparge points, borings are drilled to the desired depth needed for sparge point placement. The sparge points are set with 314 inch PVC risers with viton O-rings ' which terminate at the surface in flush mounted well boxes (traffic vaults) (figure 4). A fine sand filter pack is set to one foot above the sparge point. Two feet of bentonite is installed above the filter pack with cement grout from the bentonite to the surface as per SJCEHD requirements. In the well boxes the risers are connected to tubing that LJJW GEOSCIENCES Inc. t '