Iron in Drinking Water

Iron in drinking water and in ground waters occurs naturally in three forms, Ferrous Iron (clear water iron), Ferric Iron (red water iron), and Heme Iron (organic iron). Each type of iron in drinking water can exist alone or in combination with the others.
Ferrous iron in drinking water, or clear water iron as it is sometimes called, is ferrous bicarbonate. The water is clear when drawn but this type of iron in water effects the water and turns it cloudy when it comes in contact with air. The air oxidizes the ferrous iron and converts it to ferric iron.
Ferric iron in drinking water, or ferric hydroxide, is visible in the water when drawn; The result of this type iron in water effects the color having a red color known as "red water iron" .
Heme iron in drinking water is organically bound iron complexed with decomposed vegetation. The organic materials complexed with the iron are called tannins or lignins. The result of this type iron in water effects the color producing a weak tea or coffee color.
Certain types of bacteria use iron as an energy Source. They oxidize the iron from its ferrous state to its ferric state and then the iron bacteria in water deposit a slimy gelatinous material which surround them. The iron bacteria in water grow in stringy clumps and are found in most iron bearing waters.   
 
Iron Water Treatment - There are a wide selection of water filters for iron. Ferrous iron (clear water iron) can be removed and filtered with a water softener provided it is less than 0.5 ppm for each grain of hardness and the pH of the water is greater than 6.8. If the ferrous iron is more than 5.0 ppm, the iron water treatment solution must convert it to ferric iron by contact with a oxidizing agent such as chlorine, before it can be iron can be removed from drinking water by mechanical filtration. Ferric iron (red water iron) can simply be removed by mechanical filtration and iron water filters. Heme iron can be removed by an organic scavenger anion resin, or by oxidation with chlorine followed by mechanical filtration. Oxidizing agents such as chlorine will also kill iron bacteria in water if it is present. Lastly before you choose the correct iron water filter or water treatment solution use iron in water test to determine the amounts and levels of iron in your water.