ARCHIVED REPORTS XR0009884 - Laserfiche WebLink

Home Browse Search

Report—Remedial Action Feasibility Page 2 Cutter Lumber—Western Lift Site GPE Project No 102 3 • August 1,2003 investigate several potential methods of engineered remedial action that may be employed to adequately mitigate the contaminated groundwater As proposed in the original Work Plan dated October 30, 2001, this feasibility study was intended to assess the relative merits of four remedial options In brief, the four options are 1 Natural Attenuation This method relies on natural, in-situ degradation of contaminant hydrocarbons through the action of aerobic bacterial metabolization ' Groundwater conditions are monitored by periodically collecting and analyzing samples from groundwater monitoring wells to assess the progress of the natural Iattenuation process Soil Vapor Extraction This remedial method physically removes hydrocarbons from the vadose zone by applying a vacuum to one or more vapor extraction wells The gasoline removed in the process is then destroyed by filtration, or by one of several methods of combustion Vapor Extraction with Air SuarginThis method combines vapor extraction as described above with air sparging, injecting air into the saturated zone Introduction ' of oxygen through air sparging is intended to assist the remedial program through several mechanisms The air rising through the groundwater column mobilizes hydrocarbons bringing them toward the groundwater surface where they may be removed by vapor extraction The air also increases the dissolved oxygen, which in turn stimulates the growth of aerobic bacteria, which will then more readily metabolize hydrocarbons Vapor Extraction with Groundwater Pum in With this method, groundwater extraction wells are used to remove contaminated water while vapor extraction occurs concurrently In concept, the groundwater pumping will depress the local groundwater surface allowing more vapors to be extracted from the increased vadose zone, and simultaneously removing dissolved hydrocarbons from the groundwater Contaminated groundwater is treated prior to disposing of it 1.1 Site History The subject Property has been the subject of remedial investigations from two separate release sites The site of the subject gasoline release was discovered near monitoring well I MW-1 as a result of a groundwater monitoring event in 1996 at the Western Lift Site in the southerly part of the subject Property (as shown in Figure 2) Review of historic records revealed a former 1,000 gallon underground gasoline tank and an above ground diesel tank were situated along the western Property margin in the north central portion of • 2937 Veneman Ave,#13240 Geo-Phase Environmental Inc Phone(209)569-0293 Modesto, CA 95356 Fax(209)569-0295 1