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Geological Technics Inc. Page 6 Bank of Stockton-Western Lift Remedial Feasibility Study-Work Plan Project#358.3 September 28, 1995 After the pilot / feasibility study is completed, the two VEW wells will be maintained as groundwater monitors. 3.1 Remedial Concept The purpose of the BV/SVES system as a remedial method is to establish a pattern P P Y of air recharge and vapor extraction wells. The recharged air serves to enhance ' bacterial growth and to help create a pressure gradient toward the vapor extraction well(s). Soil remediation by vapor extraction operates by moving air through the ' contaminated vadose zone (unsaturated zone). In a steady-state vadose zone environment, the rate of liquid evaporation equals the rate of liquid condensation causing no net change of content. Increasing the evaporation rate by drawing air through the contaminated formation will cause the free phase liquid hydrocarbons to volatilize and be transported in a vapor phase to the treatment system. This process will be accelerated by the bioventing process. ' These bioventing and vapor extraction methods individually, and in tandem, have been proven effective for removing components of the petroleum mixture having high vapor pressures at common ambient temperatures. 3.2 Pilot Testing An Authority to Construct permit will be obtained (if needed) for installing air emission treatment systems from the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD). In any event, notification of intention to perform the pilot test will be communicated to SJVUAPCD in writing prior to performing the ' work. Geological Technics Inc. personnel will perform a pilot soil vapor extraction test to gauge the radius of influence of the vapor extraction well (VEW-1). Once the test equipment is installed, the pilot operation is expected to consist of a one-day soil vapor extraction test. A blower (Fuji Regenerative Blower, or equivalent, rated 200 scfm capacity, at 10 l g q HP at 7 inches of mercury vacuum pressure, 3 phase 230 volt power) designed ' especially for these types of applications (the blower assembly consists of an aluminum non-sparking wheel and an explosion proof motor) will connected to ' VEW-1 with a temporary connection made up of 4.0" diameter PVC fittings. The blower will be vented to the air through a 2.0" diameter stack with a measuring port located 25" down stream of the blower. The power to the blower motor is to be supplied by a portable generator.