Biological Removal of Iron from Groundwater

Host of the soluble iron in groundwater exists in complexes with organic matter. Removal of iron, complexed with organic matter, is difficult and requires the use of a strong oxidant such as ozone, chlorine, etc. This increases capital and operating costs of water treatment plants. Iron oxidizing bacteria like Gallionellaferruginea are known to oxidize iron and derive the energy for the reduction of CO2. A biological reactor was developed, based on these principles, to remove iron from groundwater. The reactor was successful in reducing iron levels in groundwater from 2.5-3.0 mg/l to about 0.1 mg/l. It was observed that, apart from Gallionellaferruginea, Sphaerotilus spp. were also present in the reactor column. No major problems with respect to clogging of filters or the reactor column were experienced.