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' 15 June 1999 <br /> • AGE-NC Project No 98-0450 <br /> Page 20 of 27 <br /> called "pump and treat" Pump and treat methods involve extraction of contaminated ground water <br /> from the aquifer for above-ground treatment and/or disposal Ground water extraction is performed <br /> using a submersible pump A ground water extraction system is operated to capture and reduce the <br /> ' dissolved hydrocarbon plume Following treatment, the extracted water is typically discharged to <br /> a storm drain, a sanitary sewer, or injected into the aquifer Typically, waste discharge permits are <br /> required for discharge <br /> ' The most common methods of water treatment are air stripping and carbon adsorption Air stripping <br /> is the process of nixing air and contaminated water together to facilitate the removal of volatile <br /> contaminants from water Air stripping involves removal of volatile organic compounds from ground <br /> water by promoting the transfer of contaminants from the dissolved phase to the vapor phase Carbon <br /> adsorption utilizes liquid-phase granular activated carbon to remove organic compounds from <br /> ' ground water Organic molecules are selectively adsorbed to the internal pores of the carbon <br /> granules Once the micropore surfaces of the carbon are saturated with organic compounds,the spent <br /> carbon is removed and replaced with virgin carbon Based on site-specific discharge requirements, <br /> air stripping and liquid-phase granular activated carbon may be utilized together for treatment <br /> Based on the capacity of the extraction/treatment system and local air quality district regulations, <br /> air stripper discharge may need to be additionally treated by vapor-phase granular activated carbon <br /> ' 5 2 2 Monitoring Activities <br /> Monitoring of ground water extraction and monitoring wells would be required to assess the progress <br /> and effectiveness of the system Additionally, monitoring of treatment System effluent would be <br /> required to confirm that treatment effectiveness and waste discharge requirements are being <br /> 1 achieved Monitoring activities would typically be conducted, at a minimum on a monthly basis <br /> Also, based on local air quality district requirements, monitoring of air discharge may be required <br /> 5 2 3 Feasibility <br />' Site-specific aquifer testing would have to be performed prior to initiation of a pump and treat <br /> method Large bore ground water extraction wells would need to be installed at the site Pumping <br /> tests would be required to determine aquifer characteristics for ground water modeling analysis of <br /> the capture zone of the extraction system The results of the pumping tests and ground water <br /> modeling would be used to establish the necessary rate of ground water extraction to effectively <br /> remediate the dissolved hydrocarbon plume Pumping tests would require the containment and off- <br /> site treatment/disposal of ground water generated during the tests <br /> Advanced GeoEmironnicntal,Inc <br />