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31 January 2013 AGE-NC Project No. 02-0926 Page 12 of 21 9.0. SATURATED SOIL & GROUNDWATER REMEDIAL ALTERNATIVES Based on groundwater conditions, the lateral and vertical extent of saturated soil and groundwater impact and the nature of the contaminants, AGE has evaluated four remedial technologies which apply to treating contaminated groundwater and saturated soil at the site. The four technologies include groundwater extraction, high vacuum (dual phase) extraction, air-sparging and natural attenuation. 9.1. GROUNDWATER EXTRACTION There are several different methods for treatment of extracted groundwater, which are collectively called 'pump and treat'. As the name indicates, all methods involve extraction and transfer of contaminated groundwater from the aquifer to an above-ground treatment or disposal/recycling facility. The extraction is performed utilizing an automatic pump system to maintain capture characteristics in the aquifer and to assure that process volume requirements are maintained. After treatment, the water is usually discharged into a sanitary sewer or potentially separate storm sewers. 9.1.1. Groundwater Treatment Methods The presence of dissolved hydrocarbons will require treatment for the recovered water. Two of the most common methods of water treatment are air stripping and carbon adsorption. Air stripping involves removal of volatile organic compounds from groundwater by promoting the transfer of contaminants from the dissolved phase to the vapor phase. The process usually works well with volatile organic compounds, but less successfully with longer-chained hydrocarbons. Carbon adsorption utilizes granular activated carbon to simply "filter" organic compounds out of groundwater . A third, but less common method of above-ground treatment of water is bioremediation. Contaminated groundwater is "treated" by adding hydrocarbon-degrading microbes or by augmenting natural hydrocarbon degradation activities with the introduction of nutrients. 9.1.2. Feasibility To date, aquifer pumping tests have not been completed at the site to evaluate the maximum achievable extraction rate at the site. For groundwater extraction to be effective wells would need to be installed at the site due to the lateral extent of the dissolved hydrocarbon plume. Additionally, any extracted and treated groundwater would need to be discharged at a location at the site, which currently has not been identified. Should a location not be available for discharge the cost of hauling the extracted, treated/non-treated Advanced GeoEnvironmental, Inc.