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i 3.0 Pilot Test Objective As previously indicated, biosparging is the recommended treatment alternative for the site. This technology targets specifically at contaminants that are amenable to aerobic biodegradation, such as TPH-g and BTEX, and its treatment methodology is to promote aerobic biodegradation of the hydrocarbons within the treatment area by supplying oxygen in oxygen -deficient areas. The jamount of oxygen required to sustain the microbial biodegradation process depends on the oxygen demand and the volume of treatment. With the oxygen demand determined, the capacity ' and configuration of a biosparging system can be determined. It is therefore the primary objective of this pilot test to collect the following site-specific parameters to assist in the design of the biosparging system; specifically, the well layout and the oxygen supply/delivery approach: • Injection radius of influence (ROI) for oxygen distribution • Oxygen consumption rate Nutrient levels to sustain aerobic biodegradation of hydrocarbons Data for the first two parameters will be gathered from a field test. Determination of the nutrient tlevels will be from the analytical results of samples taken from the groundwater monitoring wells. Discussions of the injection ROI and oxygen consumption rate are provided in the following subsections. 3.1 Injection Radius of Influence The injection ROI determines the number of wells and the injection pressure required to achieve effective biosparging across the treatment area. Determination of the effective injection ROI will require the performance of a biosparge test at various injection pressures and simultaneous monitoring of changes in the physical parameters of the groundwater, most importantly the dissolved oxygen (DO) and water levels, in nearby monitoring wells. The most distant well(s) tshowing at least 10 percent increase in the DO level at a selected injection pressure within the test period will be used to determine the injection ROI for oxygen delivery. It is expected that 1 the minimum ROI will be approximately 10 feet. Achieving at least this minimum value for the ROI will be a key objective of the pilot test. 3.2 Oxygen Consumption and Demand Oxygen consumption (or uptake) rate determines the frequency of oxygen replenishment ' required to the subsurface. If the oxygen consumption rate is fast (decreased to baseline condition in minutes), constant air supply will be necessary. If it is slow, timed injection cycle may be warranted to minimize energy consumption for the air supply. Oxygen consumption rate 1 Biosparge Pilot Test Final. doc 3-1 Shaw Environmental, Inc.