Iron bacteria can cause a variety of problems in drinking water. A diverse group of microorganisms widely distributed in nature, iron bacteria are commonly found in fresh water, salt water, soils and even on desert rocks. Iron bacteria derive energy as iron (or sometimes manganese) oxidizes from water-soluble to insoluble forms. This transformation can cause severe fouling problems in wells, treatment plants, filter systems, and distribution systems, as well as in industrial cooling towers and boilers.
The source of soluble iron (Fe++) for these bacteria may either be naturally occurring in the water or corroded from pipe surfaces. The ferrous iron (Fe++) is oxidized to the ferric state (Fe+++) and deposited on the outside of the bacterial cells. In combination with bacterial polymers, the precipitated iron can cause staining, taste, and odor problems in drinking water; interfere with filtration or other water treatment processes; and in some cases, form orange-red gelatinous biomass capable of plugging pumps, wells, and distribution lines. Iron bacteria may be found in association with sulfur-reducing bacteria.
