FIELD DOCUMENTS CASE 2 - Laserfiche WebLink

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FINAL REMEDIAL PLAN (FRP) • The FRP is based on the findings of the Problem Assessment investigation as well as discussions with the San Joaquin County Department of Health, the Regional Water Quality Control Board and Cheryl and Pat Mitchell of California Natural Products. Since no free gasoline product has been observed on the surface of the groundwater in the three monitoring wells installed during the Problem Assessment investigation, it was concluded that very little gasoline would be removed by pumping and treating the extracted water. As a result, the FRP will concentrate on the vadose zone soils and utilization of a soil venting process within the area of contamination. Gasoline, absorbed on the soil in the unsaturated vadose zone above the water table will be evaporated by moving air through the soil, and passing the air through activated carbon beds to absorb the volatile organics. The carbon beds will then be recharged in the field by means of steam to. produce pure gasoline for proper disposal. Since soil at field conditions retains gasoline • at residual saturation levels of up to 0.5 gal/ft 3, it is conceivable that hundreds of gallons of gasoline might be absorbed and recovered from the soil. Without recovery this gasoline will continue to contaminate the groundwater for years to come. Soil venting promises to be substantially cheaper than other methods such as removal of contaminated soil or water-based bioremediation. While venting of soil to remove gasoline has been demonstrated as effective in the past, it has in many cases involved discharging the gasoline laden air to the atmosphere. This release is considered unacceptable by the local air pollution control district and will thus be overcome by passing the gasoline laden vapors through activated carbon to remove the volatile organic components. The field recharge of carbon is desirable in order to minimize costs unless the quantity of gasoline to be recovered is very small. •