Laserfiche WebLink
20 March 1996 <br /> AGE-NC Project No 95-0130 <br /> Page 18 of 23 <br /> concentrations in the saturated zone Pilot tests have not been conducted a this i <br /> c t t s s te, but remediation <br /> times are generally comparable with soil vapor extraction times At the subject site, we estimate a <br /> remediation period of 18 to 36 months for shorter-chain hydrocarbons <br />' 7 1 6 ESTIMATED COSTS FOR IN-SITU AIR SPARGING <br />' The costs for installation of an IAS system at the TFS site, including as many as 20 IAS injection <br /> points, will be between $40,000 and $50,000 The cost to operate, maintain, monitor and sample an <br /> IAS system will likely average between $30,000 to $40,000 per year Maintenance costs can vary <br />' significantly, depending upon the specific unit utilized Based upon an estimated two year treatment <br /> period, the cost for installation and operation of an IAS system would be between $100,000 to <br /> $130,000 <br /> 7 2 GROUND WATER EXTRACTION <br /> 7 2 1 BASIC PRINCIPLES <br />' There are several different methods for treatment of extracted ground water, which are collectively <br /> called "pump and treat" As the name indicates, all methods involve extraction and transfer of <br /> contaminated ground water from the aquifer to an above-ground treatment or disposal/recycling <br /> facility The extraction is performed using an automatic pump system to maintain capture <br /> characteristics in the aquifer and to assure that water production rates meet the process requirements <br /> After treatment, the water is usually discharged into a storm drain or sanitary sewer A waste <br /> discharge permit is usually required for discharge <br /> 7 2 2 TREATMENT METHODS <br /> Two of the most common methods of water treatment are air stripping and carbon adsorption Air <br /> stripping involves removal of volatile organic compounds from ground water by promoting the <br /> transfer of contaminants from the dissolved phase to the vapor phase Carbon adsorption utilizes <br /> granular activated carbon to simply "filter" organic compounds out of the ground water <br /> A third, but less common method of above-ground treatment of water is bioremediation For this <br /> method, contaminated ground water is "treated" by adding hydrocarbon-degrading microbes or by <br /> augmenting natural hydrocarbon degradation activities by the introduction of nutrients <br />