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LFR Inc. EOS is the most commonly applied emulsified oil remediation product. During our assessment of EOS, a similar substrate, called SRS, came to the market. This product, like EOS, is a proprietary blend of soybean oil, emulsifiers, lactate, and vitamin additives. From a performance perspective, the products are considered equal. While preliminary cost estimates have been obtained for both EOS and SRS, the final selection will be determined by more detailed price quotes. 4.0 PROPOSED PHASE V IRA DETAILED PLAN The Phase V IRA includes the implementation of an ERD barrier to remediate groundwater hydraulically downgradient from the Site and in the vicinity of the Bank of Stockton. ERD has emerged in recent years as a viable approach for the in situ remediation of chlorinated hydrocarbons (especially the chlorinated ethenes PCE, TCE, DCE, and vinyl chloride) in groundwater. The degradation of these Hazardous Substances via an anaerobic reductive pathway can ultimately yield entirely innocuous end products. Injections of a variety of carbon-based substrates (HRC, molasses, sodium lactate, cheese whey, vegetable oil, etc.) by LFR and others have demonstrated the capability of ERD to induce changes to an aquifer's geochemical parameters (oxygen depletion, reduction of ORP, increase of TOC) that create a favorable environment for the biological communities of Dehalococcoides responsible for the anaerobic reductive dechlorination of targeted Hazardous Substances. The successful application of ERD is dependent on adequate delivery and dispersion of the injected substrate. Therefore, appropriate substrate volumes, coupled with effective lateral spacing of injection wells and the vertical positioning of screen intervals, have been selected to achieve adequate substrate delivery to the targeted core plume treatment area. 4.1 Recommended ERD Well Spacing and Layout The recommended substrate injection well layout is depicted in plan view on Figures 4 and 5. The cross section of Figure 6 includes lines depicting the plan-view locations of the geological cross sections represented on Figures 7 and 8. Performance monitoring wells and screened intervals appear on Figure 7; injection wells and screened intervals are shown on Figure 8. The proposed layout includes 22 injection wells in a barrier- type array and six downgradient performance monitoring wells configured in two clusters of three. LFR has found at sites with similar hydrogeological conditions that the ROI for dilute emulsified edible oil injection has been greater than 15 feet. To be conservative, a 15- foot ROI was used in the design process. For conceptual purposes, the injection can be imagined as creating a substrate-laden cylinder around the well's screened interval. The Page 18 wp-PhV_IRA-Sep07-Final-06750.dm:lfr