Currently around a billion people are at severe risk from drinking contaminated water, and whenever there is a major human crisis refugees are placed in the same plight. The main solution would seem to be drilling wells that tap groundwater that aerobic bacterial action cleanses of most pathogens. That is essentially true, but some groundwater is rejected even by people suffering the most extreme privations. It has the appearance of water from the radiator of an aged lorry, because it contains abundant dissolved iron that immediately precipitates as red-orange slime when exposed to the air, tainting food and staining clothes. A solution may arise from studies as far from drought-stricken areas as one could possibly get; concerning the way in which deep-sea wrecks decay away. The discovery of the wreck of the Titanic in 1985 and recovery of parts of it later by marine historian Robert Ballard, revealed that its ironworks were being consumed by bacteria that created stalactite-like masses of iron oxides, known as “rusticles”. Detailed microbiological studies found a highly complex harmony of different bacteria that created and inhabited the rusticles. Effectively, they were eating the mighty ship at a rate of about a tonne every ten days by exploiting the energy released by oxidation of iron. It may prove possible to harness the habits of these iron-loving bacteria to remove iron from groundwater and make it palatable
Source: Fry, C. 2003. Iron rations. New Scientist, 26 July 2003, p. 36-37.