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23 April 2002 <br /> AGE-NC Project No 95-0142 <br /> Page 7of16 <br /> 3 4 TREATMENT SYSTEM <br /> AGE proposes the use of three in-line 2,000-pound absorption vessels to treat extracted ground <br /> water, granular activated carbon (GAC) will be the treatment media contained in the absorption <br /> vessels Prior to processing, one 750-gallon polyethylene tank will be used to temporarily store <br /> extracted water This tank is equipped with upper and lower level control switches that serve to <br /> control the rate at which extracted water is introduced into the GAC, to provide safety shutoff <br /> capabilities, and to allow coarse sediment to settle out prior to treatment The process pump is <br /> located after the holding tank <br /> The GAC absorption vessels are designed to adsorb TPH-g,BTEX compounds and MTBE Sample <br /> ports will located between the raw water process holding tank and each carbon vessel to allow raw <br /> water sampling for analysis, to detect the process break-through concentrations and to obtain final <br /> discharge samples (Figure 4) <br /> A 15-by 20-foot chain-link gated enclosure will be installed in an eastern section of the site to secure <br /> the ground water treatment unit as well as the vapor extraction unit The proposed location of the <br /> gated enclosure is illustrated in Figure 4a <br /> 35 WELL AND PROCESS PUMP CONTROLLERS <br /> The extraction well pumps will be controlled by PumpTec controllers, an amperage sensing/time <br /> control switch This switch will detect a decrease of amperage when water level drops below the <br /> impeller intake of the Grundfos pumps and temporarily suspend pump operation to prevent pump <br /> damage <br /> The process pump,located downstream of the holding tank,will be controlled by electrode switches <br /> placed at various levels in the holding tank An emergency shut-off switch will be located <br /> immediately below the top of the holding tank An intermediate pump-on switch will be placed <br /> approximately 8 inches below the emergency shut-off switch to activate the process pump <br /> Intermediate pump-off switches will be utilized near the bottom of the holding tank to turn the <br /> process pump off when the tank has a low water content <br /> 3 6 REMEDIATION SYSTEM START-UP PERIOD <br /> Prior to the pump and treat start up period, treated water will sampled and analyzed to monitor <br /> treatment efficiency The system will be activated after treatment verification to allow for discharge <br /> of treated ground water During the pump and treat start-up period(first two weeks of operation), <br /> Advanced GeoEnvironmental,Inc <br />