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The Southern California Water Company has conducted testing to simultaneously removearsenic and manganese from groundwater at its Centralia plant south of Los Angeles. Thetesting was funded in part by the AWWA Research Foundation as a Tailored Collaboration. Theproject included bench- and pilot-scale process testing, design and construction of full-scaleimprovements, and full-scale trials to investigate the potential for chlorine and ferric chlorideaddition followed by filtration to simultaneously remove arsenic and manganese.Many wells in Southern California have been equipped with pressurized filters formanganese removal. However, the manganese removal process (oxidation/direct filtration) isnot very effective for arsenic removal especially when iron concentration in the groundwater islow. There are several known treatment technologies for arsenic removal, including bothconventional processes (e.g., coagulation/filtration and softening) and emerging technologies(e.g., coagulation assisted membrane processes and proprietary adsorbents). However, most allof them are not feasible for urban groundwater wells to address the particular arsenic/manganese concern due to larger space requirements, multiple chemical handling, and high costs.Since many well sites in Southern California are adjacent to residential areas, a small footprintand minimum chemical usage are often required.The specific goals of the research were to answer the following key questions:will chlorine and ferric chloride addition followed by filtration simultaneouslyremove arsenic and manganese;what is the relationship between ferric chloride dose and filtered water arsenicconcentration;how effectively will bench-testing estimate the required ferric chloride dose toachieve the target filtered water arsenic concentration;how effectively will pilot-testing estimate filtration design and operatingparameters including filter run time; and,what are the optimal design and operating parameters to achieve the targetfinished water arsenic concentration with minimum water waste and sludgeproduction?The following major tasks were performed to investigate arsenic and manganese removal:analysis of existing conditions;bench-scale testing;pilot-scale testing;design and construction of full-scale improvements;full-scale testing; and,data management and reports. Includes tables, figures.

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Edition: Vol. - No. Published: 06/15/2003 Number of Pages: 17File Size: 1 file , 990 KB