Well Water Systems - Rusty Water

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The 5 Types of Iron

From a water treatment basis there are five different categories of iron:

1. Ferrous Iron:

Ferrous iron: This is often referred to as “Clear Water Iron”. Water having only clear water iron is completely clear, hence the term clear water iron. Since the iron is not rusted and remains in the Fe ++ form it is not visible to the naked eye. If proper water chemistry is present the iron will rust to a visible brown color once it is exposed to air (such as in the toilet bowl or a dogs water dish). However, when drawn directly from a deep well it is generally clear. Water which only contains ferrous iron can be very effectively treated with a specially designed water softener capable of removing iron. Only certain water softeners can effectively deal with higher ferrous iron levels since many conventional water softeners will prematurely become fouled with iron and fail prematurely. In some cases these softeners are equipped with special ion exchange media which is resistant to iron fouling. In other cases special cleaning protocols allow for the softener to function in a high iron environment without failing prematurely.

2. Ferric Iron:

The other four types of iron are all variants of ferric iron but are all influenced by other factors which may complicate treatment so we refer to them as separate iron forms.

3. Bacteria Iron:

Bacteria iron is actually ferric iron that has been oxidized by a special type of bacteria. These bacteria actually oxidize ferrous iron to the ferric form. If left untreated, bacterial iron can foul iron filters and water softeners greatly reducing the effective life of the water treatment system as well as fouling the plumbing system. Iron bacteria are not considered a health threat but do cause numerous esthetic problems with plumbing fixtures, clothes and appliances.

4. Organic Iron (sometimes called Heme Iron):

This type of iron is not common in Santa Cruz country so we will only briefly reference it. It is ferric iron that has reacted with decomposed organic matter such as leaves and plant material.

5. Colloidal Iron:

Certain parts of Santa Cruz County have a significant problem with colloidal iron. This iron is not present in waters with totally clear water iron. Since it is a form of ferric iron it only presents itself when the iron has oxidized. A complete water analysis of the raw well water (pump directly from the aquifer) will often allow for us to predict if colloidal iron will be a problem. An extensive water test is highly recommend prior to installation of a storage tank since the exposure ferrous iron to air is the catalyst for formation of colloidal irons on some water chemistry types. In newly constructed homes the fire marshal will generally require the installation of a storage tank. In those instances we are left with no other solution than to design water treatment systems that can effectively treat colloidal iron formed in the storage tank. Each colloidal iron treatment system must be designed for the individual system in question. But treatment may consist of coagulation, submicron filtration, or in some cases altering the basic water chemistry to prevent the formation of colloidal iron upon the oxidation of the ferrous iron to the ferric form.