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MAY 2 0 1999 <br /> '." i.:'JhIENTAL HEALTH <br /> ARSENIC CONTAMINATED t'EA,v;:i/SERVICE$ <br /> GROUNDWATER TREATMENT PILOT STUDY <br /> AT <br /> SHARPE ARMY DEPOT (SHAD) , LATHROP, CA <br /> 1. Project Objective <br /> The objective of this pilot study is to evaluate and confirm the capability of <br /> Ion Exchange (IE) , Granular Activated Carbon (GAC) , and Activated Alumina (AA) <br /> to treat arsenic in groundwater at Sharpe Army Depot (SHAD) , Lathrop, CA. <br /> 2. Pilot Plant Location <br /> The continuous flow pilot-scale investigation will be conducted near wells 403 <br /> and 431 at SHAD. (Refer to the attached map of site) . <br /> 3. Well Location <br /> Wells 403 and 431 are located at the south side of the installation as shown <br /> on the attached map. <br /> 4. Groundwater Characteristics <br /> The test water used in this study will be groundwater from wells 403 and 431, <br /> A zone, at a concentration of approximately 200-300 ppb, and trichloroethylene <br /> (TCE) at concentrations less than 50 ppb. <br /> 5. Pilot Plant Discharge <br /> The treated water from the pilot plant will be discharged into the storm sewer <br /> at the same point as the South Balloon Aquifer Restoration Plant discharge. <br /> This discharge is routed to a discharge point into the South San Joaquin <br /> Irrigation District drainage canal . The pilot plan effluent will be stored <br /> temporarily in above ground tanks pending analysis for arsenic and possibly <br /> chlorine residual prior to discharge. <br /> 6. Pilot-Scale Treatment System <br /> GAC/IG/AA pilot 1p ant. The GAC/IE/AA performance evaluation will be <br /> conducted in a skid-mounted GAC/IE/AA pilot plant. This unit consists of <br /> three skids and accessory tankage. One skid contains the motor control <br /> center, the teed pumps , and utility pumps. Each of the other two skids <br /> contains four plexiglass columns that can be used for testing activated <br /> carbon, ion exchange, and activated alumina treatment systems. The system was <br /> designed to provide a high degree of operating flexibility using variable bed <br /> lengths and flow arrangements. <br /> Air Stripper An air stripper will be used to remove TCE from the <br /> groundwater prior to treatment in the GAC/IE/AA unit. The air stripper is 8" <br /> in diameter by 23' high, with 15' of packing and is designed for a water flow <br /> rate of 5 gpm. <br />