Iron Contamination in Well Water
The most common forms of iron contamination in the Northwest are ferrous (dissolved invisible iron), ferric (visible iron), and colloidal organic iron.
Removing ferrous iron
Invisible/ferrous iron can be removed with a water softener or an iron filtration system. If you have crystal clear water with a low pH and low alkalinity, up to 3-4 parts per million of invisible iron can be removed with a water softener. If you do not want soft water, invisible iron can be removed with an iron filter.
Removing ferric iron
Visible/ferric iron can be removed with an iron filtration system. In most cases, when visible iron is present, there is also a quantity of invisible iron present as well. The process the iron filter uses is to oxidize any invisible iron to make it a visible particle, so it can be trapped and removed along with the existing visible iron.
Removing colloidal organic iron
Colloidal organic iron is formed when invisible iron bonds with an organic material such as tannins or phosphates and remains too small to be filtered out by standard iron filtration methods. Removal systems include coagulant injection systems and ultra-filtration.
Choosing the right equipment to remove iron
Care must be taken when considering iron removal systems as there are many factors to consider. Water temperature, pH, alkalinity, dissolved oxygen content, and other factors will affect the results of the equipment you choose. Most application failures are caused simply by mis-diagnosing the type of iron in the water, which leads to the wrong kind of equipment being used.