Iron/Manganese:  Ferrous, Ferric & Bacteria

Iron in water is a very common water quality issue and most common in groundwater sources rather than shallow wells. Where quantities of iron are found, it almost always indicates that manganese, too, is present. As there are three types of iron that can be present in water, it is prudent to determine which type, as they may be treated differently and some types are harder to remove than others.

Ferrous Iron: Iron that remains dissolved in the water when exposed to the air. Usually detected by the reddish-brown tinge it gives to water.

Ferric Iron: Iron that forms particles when exposed to the air.  Usually detected as small black particles when water is allowed to settle.

Organic Iron or Iron Bacteria:  Iron bacteria forms reddish-brown growths that may clog pipes and reduce flow rates. They can be detected in water that has been allowed to settle and appear as a reddish-brown "slug". This bacteria is not considered harmful, but it is not at all pleasant to drink.

Iron and manganese will often present themselves as staining on fixtures that is very difficult to remove. It may also indicate that the water is extremely acidic. It can cause bad taste and odours. Often, if organic iron or iron bacteria is present, it will clog pipes and  reduce flow rates. For these reasons, the type of iron present should be determined as their treatment methods vary. 

Iron and manganese can be treated in three different ways, depending on the type present and the quantity.  Ion exchange water softeners and conditioners can be used if  if the amount of iron and manganese is low -- less than 5.0 ppm.

The oxidation and filtration method uses an oxidizing agent -- usually chlorine or potassium permanganate -- that is added to the water. The process converts the ferrous iron into ferric iron -- remember ferric is the solid state of iron -- allowing for the iron to be filtered out through a resin bed. This type of water treatment is commonly called an iron filter.