ARCHIVED REPORTS XR0009533 - Laserfiche WebLink

Home Browse Search

' Former Manna Pro Site Page 2 Project No 207 3 1 Remedial Feasibility Study • Natural Attenuation This method relies on natural, in-situ, degradation of contaminant ' hydrocarbons through the action of aerobic bacterial metaboltzation Groundwater conditions are monitored by periodically collecting and analyzing samples from groundwater monitoring wells to monitor the progress of the natural attenuation 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 Sparg ng This 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 I extraction The air also increases the dissolved oxygen, which in turn stimulates the growth of aerobic bacteria The aerobic bacterial will then more readily consume hydrocarbons by metabolizing them Vapor Extraction with Groundwater Purnpmg 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 former Manna Pro facile was originallyconstructed in 1956 as a rain mill that h' g processed animal feed products Two 10,000 gallon underground diesel tanks and two 5,000 gallon underground gasoline tanks and a single 10,000 gallon underground gasoline tank were formerly in use at the site Petroleum hydrocarbons were detected in soil samples from beneath 4 of the 5 tanks Based on the results of this initial soil sample analysts, several hundred yards of fuel-impacted soil were excavated The excavation reached a total depth of about 15 feet In October of 1990, ERM West conducted additional work to characterize the lateral and vertical extent of the hydrocarbon contamination in the sub-surface This included installing I 25 soil borings into groundwater of which, a total of 6 borings were later converted to groundwater monitoring wells Between 1993 and 1996, Groundwater Technology Inc (GTI) installed four additional monitoring wells, a combination groundwater/vapor extraction Iwell and three observation wells These observation wells and extraction well were used for . the completion of a simultaneous groundwater pumping and vapor extraction pilot test In 2937 Veneman Ave,#13240 Geo-Phase Environmental Inc Phone(209)569-0293 Modesto,CA 95356 Fax(209)569-0295 1