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1 <br /> tUmind Water Extmction and Treatment <br /> Ground water extraction and treatment is generally an effective <br /> method for the treatment of hydrocarbons in water. This alternative <br /> consists of installing wells into the saturated zone and reversing the <br /> hydraulic gradient by extracting the affected ground water. The <br />' ground water is then either treated to remove the constituents of <br /> concern or discharged directly to the city sewer lines. Typical <br /> treatment methods include air stripping and liquid-phase activated <br />' carbon filtration. <br /> Ground water extraction and treatment is a proven, effective method <br />' for remediating hydrocarbons in ground water and reducing the <br /> potential migration of chemicals in ground water. Implementation <br /> of this alternative would be simple because conventional drilling <br />' equipment is normally used For this site, existing monitoring wells <br /> could potentially be utilized as extraction wells, which would result <br /> in a significant cost savings Ground water treatment costs would be <br />' dependent upon operational parameters including permitting <br /> requirements, extraction flow rates, and time required for treatment. <br /> Ground water extraction and treatment is effective and could be <br />' implemented, and therefore is considered a potentially appropriate <br /> remedial alternative for the site. <br /> An available option for this alternative would involve the extraction of <br /> Ma fixed volume of hydrocarbon-containing ground water during a <br /> single pumping event (ground water would be extracted from the <br /> existing monitoring wells). The extracted water could be aerated and <br /> discharged directly to the sewer, or aerated, polished with liquid- <br /> phase activated carbon, and then discharged to the sewer This <br /> option is appropriate given the limited extent of the hydrocarbons in <br />' ground water at both saes It may be possible to remove the bulk of <br /> the hydrocarbon-containing ground water at each site by extracting a <br /> ground water aliquot. This would expedite natural degradation of <br />' any residual hydrocarbons. A steady decline in concentrations of <br /> hydrocarbons in ground water at, Site #1 has already been observed <br /> over time. Also, no sigrnficant migration of chemicals in ground <br />' water has been observed over time. In fact, the extent of <br /> hydrocarbons in ground water at both saes has been relatively stable <br /> over time. <br /> 1 <br />' Biotreatment of hydrocarbons in ground water would involve ether <br /> in situ or ex situ methods. For passive in situ treatment, the <br /> appropriate nutrients and microbes would be infected directly into <br />' the affected ground water to stimulate in situ bioremediation. <br /> Alternatively, for active in situ treatment, affected ground water <br /> could be extracted, aerated and inoculated with nutrients and <br /> 7-7 <br /> 1 <br />