AWWA WKICO66066

This powerpoint presentation begins by providing background information on manganese chemistry. Manganese treatment options are listed, along with manganese speciation, oxidant use for manganese reduction, and chlorine dioxide for manganese reduction. Three case studies are outlined from the northeastern, southeastern and Rocky Mountain areas of the country. Summary: chlorine dioxide is a viable alternate oxidant for achieving finished water soluble manganese < 20 µg/L in surface water treatment plants where total organic carbon (TOC) is present, without exceeding the MRDL/MCL (chlorite); chlorine dioxide should be included in evaluations of feasible oxidation options for manganese removal; testing must include analysis of chlorite and chlorate yield to ensure compliance with MCL; if soluble manganese exceeds 0.4 mg/L may need other oxidants (dependant on chlorite yield); pay attention to speciation in raw and settled manganese concentrations; and, new systems exist that can generate chlorine dioxide without chlorine gas usage. Includes tables, figures.