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<br /> <br />• Recover and properly dispose of fluids perched above the I-IDPE membrane which <br />currently lines the AST fueling facility to prevent any additional trapped diesel product <br />from entering the subsurface; <br />• Remove and properly dispose of the HDPE membrane which currently lines the AST <br />fueling facility to expose surface soils saturated with diesel product; <br />• Install and operate adual-phase extraction system to recover free product from the <br />subsurface, and to inhibit further migration offree-phase product. <br />Dual-phase extraction technology involves the removal of total fluids and soil vapor from <br />the subsurface. Fluids are removed using a high vacuum which is applied to an extraction <br />tube. The extraction tube is inserted into a well with the bottom end positioned slightly <br />below the ground water table. As the vacuum is applied, an initial slug of product and <br />water is removed. As the water table is lowered to the level of the bottom of the extraction <br />tube, additional product and water are removed as they become entrained in the vapor <br />stream. The depression of the water table creates a cone of depression, and together with <br />the applied vacuum to the soil, additional free product flows towazd the extraction well. <br />The benefit of this technology is the recovery of free product while mobilizing air flow in <br />the subsurface. This air flow not only involves the recovery of volatilized soil vapors, but <br />also the drawing of fresh ambient air to enhance biodegredation of product. <br />ERM-ROCKY MOUNTAAI, MC. <br />P:\I000\SWPC\961019UtEPORT.DOC Prin¢d on Rcrycled Paper <br />10 <br />