AWWA ACE54284

This paper presents full-scale project experiences of design, installation and operation of two wellhead arsenic treatment facilities using iron-based adsorption media. The subject wells are located in an urban area in Los Angeles County, California. Approved arsenic treatment technologies such as IX, AA, or Coagulation/MF are not suitable for those small sites due to large space requirements as well as chemical/brine/sludge handling in a residential neighborhood. The small-scale pilot study indicated that a pressure vessel with the iron-based adsorption media provides a feasible solution for arsenic treatment at the subject sites. Based on the results of the pilot study, granular ferric hydroxide and other similar iron-based adsorption medias were selected for two full-scale treatment facilities. Since the subject wells also have high manganese, a concurrent manganese removal process by Pyrolusite media was selected prior to arsenic treatment. Projects have been under construction and normal operation and monitoring will start April 2001. Both arsenic and manganese removal is expected to be achieved. The capital cost of the treatment facility is less than one third of the Best Available Technologies for arsenic treatment. The media is expected to be disposed of as non-hazardous waste per federal and California testing procedures. Includes tables, figures.