Iron is the fourth most abundant mineral in the earth’s crust. Soils and rocks in Minnesota may contain minerals very high in iron, so high in fact, that taconite can be mined for its iron content. Iron gives the hemoglobin of blood it’s red color and allows the blood to carry oxygen. The iron in a metal pail turns to rust when exposed to water and oxygen. In a similar way, iron minerals in water turn to rust and stain plumbing fixtures and laundry.
What does Iron Bacteria mean?
Iron bacteria are tiny living organisms that feed on small amounts of iron in water. Iron bacteria can cause problems for water and the components of the water system itself. It is one of the most complicated and costly problems facing drinking water utilities.
Iron bacteria naturally occurs in:
Shallow groundwater
Surface waters
These bacteria combine iron (or manganese) and oxygen to form deposits of rust, bacterial cells, and a slimy material that sticks the bacteria to well pipes, pumps, and plumbing fixtures.
Iron bacteria are nourished by carbon and other organics, and it is essential that these are not introduced into any part of a well system during the drilling process.
Corrosionpedia explains Iron Bacteria
Iron bacteria are bacteria that derive the energy they need to live and multiply by oxidizing dissolved ferrous iron. The resulting ferric oxide is insoluble, and appears as brown gelatinous slime that stains plumbing fixtures as well as clothing or utensils washed with the water carrying it.
Iron bacteria are known to grow and proliferate in waters containing as low as 0.1 mg/l of iron. However, at least 0.3 ppm of dissolved oxygen is needed to carry out oxidation. Iron bacteria often colonize in wells, coating the walls of the casing with the slimy mass.
Iron bacteria are considered a major source of microbial corrosion in many environments having iron surfaces. Groundwater wells are good examples of an iron environment. The growth of iron bacteria depends on the surrounding water environment with specific iron and manganese concentrations, pH and other chemistry. Iron bacteria can cause:
Unexpected need for disinfection
The name iron bacteria identifies a number of organisms that are categorized as autotrophic, meaning they derive their carbon from the carbon dioxide (CO2) in the air, and their energy from consuming (oxidizing) dissolved iron or manganese. Iron bacteria are approximately 1-2 µm wide and 3-15 µm long.
Since it is difficult to eliminate iron bacteria once they are present in well systems, prevention is the best safeguard against accompanying problems. Treatment techniques which may be successful in removing or reducing iron bacteria include:
Physical removal
Chemical treatment
The bacteria are not known to cause disease, but they can:
Cause undesirable stains, tastes and odors
Create conditions where other undesirable organisms may grow
Corrode plumbing equipment, such as pipes
Reduce well yields (clog screens and pipes)
Increase chances of sulfur bacteria infestation