A Review of Biological Iron Removal

Soluble Fe(II) in ground water in Denmark is mostly removed conventionally by the simple process known as purely physico-chemical (or abiotic). By this process, the raw water is exposed to atmospheric oxygen to oxidise the iron from soluble Fe(II) to insoluble Fe(III) oxides, which is then removed by single or double filtration units, depending on the ground water quality. Ground water containing iron complexed with organic and inorganic materials could be difficult to remove by the purely physico-chemical method. While humic acids could retard the oxidation of Fe(II), inorganic elements such as silicate could enhance the formation of highly dispersed colloidal iron particles which could easily go through the filter materials making it difficult to be removed. Biological iron removal is known to overcome most of the problems associated with the application of conventional iron removal processes. Therefore, this script reviews pertinent literature on biological iron removal.