Hydrous Manganous Oxide (HMO) Process for Radium Reduction - Design andPractical Operating Experience

摘要

The majority of municipal water treatment plants in the United States utilize groundwaterrnfor their public drinking water supply. To meet capacity and quality requirements, arnnumber of communities utilize deep wells which pass through soils that containrnradionuclides. Many times, the radium concentration in the water from these deep wellsrnexceed the USEPA Maximum Contaminant Level (MCL) of 5.0 pCi/l (picocurries/liter)rnfor combined radium 226 and radium 228. (1)rnRadium has been shown to be effectively removed through a number of treatmentrnprocesses including ion exchange, lime softening, reverse osmosis (4) and HydrousrnManganous Oxides (HMO) treatment. HMO treatment has shown to consistently removern60-80 percent of the radium from the raw water. With proper chemical dosages andrndetention time, removal rates of over 90 percent are possible. (2) A by-product of radiumrndegradation is gross alpha which currently has an MCL of 15 pCi/l. HMO treatment hasrnalso been proven to substantially reduce gross alpha concentrations to meet MCL levels.rnThis paper details the design considerations of HMO treatment for radium reduction.rnDetails discussed include pilot and full scale design and operation, waste disposalrnconsiderations, effects on final water quality, and summary of target water conditions. Arncase study of a full scale system operating for 10 years is also included.