Biological Treatment for Removal of Iron, Manganese, and Arsenic from Groundwater

Abstract

Many groundwater supplies are contaminated by varying levelsof iron (Fe), manganese (Mn), and arsenic (As) in concentrationsthat exceed the drinking water guidelines. Fe and Mn are removedfrom water supplies mainly for aesthetic and operational objectives,whereas As must be removed from drinking water because ofits numerous health hazards. Conventional treatment methods forremoval of Fe2+ and Mn2+ from groundwater are based on physicochemical processes such as aeration, chemical oxidation, coagula-tion, and rapid sand filtration. An alternative method is based onbiological process of Fe and Mn oxidation and deposition mediatedby microbial consortia fixed in biological filtration reactor. Inaddition, this method is possibly applicable to As removal, sincesoluble As oxyanions are known to be adsorbed onto Fe and Mnoxides produced by the biological treatment process. In this chapter,research advances toward unraveling the mechanisms of biologicaltreatment of Fe and Mn, as well as the potential application ofbiological Fe and Mn oxidation processes for As removal fromgroundwater are discussed.