Laserfiche WebLink
hydrocarbons to groundwater could necessitate a groundwater treatment system to contain and treat <br /> additionally leached hydrocarbons. Groundwater treatment would require the withdrawal of <br /> petroleum hydrocarbons from beneath the site and would result in prohibitively expensive <br /> groundwater treatment. The risks and prohibitive cost of in-situ bioremediation eliminate this option <br /> from further consideration. <br /> 6_5 Soil Vapor Extraction <br /> The VET described herein was performed to evaluate the technical feasibility of employing in-situ <br /> vapor extraction at the site. Vapor extraction has proven to be one of the most successful in-situ soil <br /> treatment technologies for the removal of volatile compounds such as TPHg and BTEX from vadose <br /> zone soil. In some cases where VES air flow contacts groundwater, varying degrees of groundwater <br /> restoration has occurred. <br /> The results of the VET performed at this site indicated that vapor extraction is feasible and could <br /> provide an initial start-up system TPHg mass extraction rate of approximately 300 ppd. An effective <br /> ROI of approximately 35 feet(based upon a per well extraction flowrate of 50 scfm from VW-1 and <br /> VW-2)could be established to capture petroleum hydrocarbons existing in on-site vadose zone soil. <br /> It is estimated that a 100 scfm therm-ox based VES operated for a 12 to 18 month period of time <br /> would be required to volatilize and capture the extractable TPHg mass in soil. The estimated cost to <br /> construct, operate and maintain such a VES for a period of 24 months (including the purchase of a <br /> new therm-ox)ranges from approximately$90,000 to $125,000. <br /> Project No.S8100-06-11C -8- December 17,1996 <br />