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N l III Nature and Extent of Contamination The vadose soil under the station contains gasoline and oxygenates that still remains. The soil zone extends to about 30 feet below the surface. There are pockets of contamination in the vadose zone around all the wells on site. The ground water has a contamination plume that extends horizontally from MW-9 to MW-11 . Well MW-11 is the most easterly well at this site . The vertical depth of the plume is from the water table to an unknown depth but boring B-4 found contamination at 160 feet bgs. In the past we had a Vapor Extractor System operating starting in July 1997 to July 2003 . The system removed about 46,411 pounds of gasoline vapor from this site. On July 27 and 28, 2005 we installed two monitoring wells (MW- 14 and MW-16) to test the contamination . IV Contaminate Transport The Hydraulic Conductivity of the groundwater is 0. 07203 Feet/Day or 0. 00060 Feet/ Minute , The shallow ground water flows to the northeast. This shallow groundwater is retained from descending by a clay layer located at 38 to 42 feet bgs on the west side of the station . The majority of the contamination originates near a line from MW-6 to MW-4; it flows to the east from that point. The highest point of contamination is in well MW- 1 . To treat this contamination , we will have to treat the water along that line and near the highest source area around MW- 1 . V Remedial Action Objectives and Processes The contamination plume could be treated with processes to destroy the contamination as it passes through the area. This can be performed by using a C-Sparger System or by treating the groundwater with a PulseOX 100 system or by Process 3. Process 1 The C-Sparger wells will be placed in the area near the edge of the site plume, Our plan would be to place a C-Sparger System in the area close to the east edge of the plume at this site . The work plan will show the position of the wells and their depth . This will be accomplished by placing six (6) sparging wells in front of the plume. The ozone sparging process employs nano-to micro-sized bubbles of air encapsulated ozone, created by forcing the air/ozone mixture through Spargepoints into the groundwater. The micro bubbles are pulsed through cleaning up the groundwater. After the initial reaction , ozone will decompose to oxygen. 5 ISI