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Ms. Lori Duncan Project 880-039.1A April 12, 2002 Page 4 Soil Cuttings and Purge Water Soil cuttings generated during drilling operations will be temporarily stored on site in DOT approved 55 -gallon drums pending characterization. A California -certified disposal contractor will remove soil cuttings to an appropriate disposal facility. Water generated during steam cleaning will be temporarily stored in DOT -approved 55 -gallon drums pending transport by the disposal contractor to an appropriate disposal or treatment facility. Water from development, and sampling of wells will be contained in a portable polyethylene tank. The tank will be transported and stored at the IT office pending laboratory analysis and disposal of the groundwater. FEASIBILITY TESTING Currently a soil vapor extraction (SVE) system is being utilized at the site to remove volatile and some semi -volatile contaminants from the soil. The volatilized petroleum hydrocarbons and MTBE extracted from soil is destroyed using a Stealth Bobcat Catalytic Oxidizer rated at 100 cubic feet per minute (cfm). Soil vapors are extracted from four shallow zone and three deep zone SVE wells. Influent concentrations have significantly decreased since system startup in 2000, which indicates the system may be reaching a steady state level. To aid in continued removal of hydrocarbons in the shallow zone the SVE will be run intermittently (pulsed operation). Beginning in the second quarter 2002, the system will be run two weeks on and two weeks off. The duration of down and up time may be increased to allow for additional rebound time of soil vapors. Groundwater extraction may be used in conjunction with SVE to keep groundwater from rising into the unsaturated zone as a result of vacuum pressure, or to increase the thickness of the unsaturated zone. This area, called the capillary fringe, is often highly contaminated, with free phase liquids, light non -aqueous phase liquids, and soil vapors that have volatilized from the dissolved phase in groundwater. In soils where the IT CORPORATION SAC:\\\SACRFP 1 \COMMON\sacDP\2002\PRJ\PJ8\880\8800391 A.2ac.doc (01040000)