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LFR Inc. Emulsified edible oils have a moderate cost per unit of hydrogen. Several soluble substrates have lower costs, while both HRC products were considerably more expensive. HRC and HRC-X injection costs are predicted to be higher based on the need for a relatively larger number of injection points and difficulties in reaching the required injection depths. As discussed in Section 3.4, emulsified edible oil (either EOS or SRS) was selected as the best substrate to meet the goals of the Phase V IRA. 4.2.1 Substrate Requirement Determining substrate requirements for an ERD system is one of the greatest challenges of the design process. Two different methods were employed to calculate substrate requirements. The approach of the first method was aimed at achieving a target TOC concentration, and the second method was based on a more complex model of hydrogen demand and groundwater flux through the treatment area. Empirical TOC/Pore Volume Approach to Determining Substrate Requirement The TOC/Pore Volume approach begins with the selection of an ideal desired TOC concentration. The range of TOC concentrations in the treatment zone recommended in "Principals and Practices of Enhanced Anaerobic Bioremediation of Chlorinated Solvents" is 100 to 1,000 mg/1 (AFCEE 2004). The table below presents the variables used to calculate EOS or SRS emulsified edible oil substrate requirements to satisfy a design TOC concentration of 200 mg/1. A TOC of 200 mg/1 has been found to be effective at other sites with similar hydrogeology and Hazardous Substance constituents. Once a desired TOC concentration is chosen, the volume of water to treat is then calculated using the dimensions of the groundwater plume multiplied by the effective porosity. Our treatment zone is the saturated permeable soils of the core plume in the A zone, which is estimated to be 40 feet thick, 350 feet wide, and 850 feet long. Effective porosity was assumed to be 23%. The calculated volume of this zone is about 77 million liters. In both EOS and SRS, the percentage by mass of the product that is vegetable oil is 60% and the percent of vegetable oil that is carbon is about 77%, leading to a carbon fraction from oil in these products of about 46%. Similarly, in both EOS and SRS, the percentage by mass of the product that is sodium lactate is 4% and the percent of sodium lactate that is carbon is about 32%, leading to a carbon fraction from sodium lactate in these products of about 1.3%. The sum of these two carbon sources accounts for about 48% of their total mass. Multiplying the volume of treatment water by the desired TOC concentration and dividing by the fraction of carbon in the substrate yields the required mass of substrate. The emulsified substrate is neutrally buoyant with a density equal to that of water (8.3 pounds per gallon). Dividing the required number of gallons of substrate (8,566 gallons)by a drum size of 55 gallons leads to a substrate requirement of 156 drums of emulsified edible oil product. Page 20 wp-PhV_IRA-Sep07-Final-06750.dm:1fr