Being a reactive element, iron is oxidized readily in the presence of oxygen. Red, yellow, and orange colors visible in the soil and rocks are usually iron-oxides.

Rainwater, as it infiltrates the soil and underlying geologic formations, dissolves minerals containing iron: eventually this iron contaminates groundwater and surface water.

Iron is found in four different forms:

• Ferrous (Fe++) - known as “clear water iron”; soluble and not visible in poured water. Found in deep wells or groundwater.
• Ferric (Fe+++) - called “red water iron”; Insoluble, when poured into a glass, it appears rusty or has a red or yellow colour.
• “Bacterial iron” known as iron biofouling. It occurs in soil, groundwater, and surface water.
• Naturally occurring iron appears in the form of deposits of slime and may be coloured brown, red, or white.
• Organic iron can combine with various naturally occurring organic materials and exist as an organic complex. This form of iron can be found in shallow wells and surface water in yellow or brown colours.

The hardness and acidity of water can affect how much iron dissolves in the water. Iron does not pose a health hazard, but it is considered to be an aesthetic contaminant. Iron depositing and fouling can result in an unacceptably high number of maintenance concerns, in addition to operational issues in water/process water treatment and remediation technologies.

Presence of iron generally results in:

• Odour, undesirable taste, coloured water, and stains on fixtures
• Build up in pumps, pipes, tanks, and screens
• Plugging air strippers, blinding bag filters, and saturating carbon beds
• Hydrogen sulfide gas (H2S), a frequent derivative of iron bacteria, gives water a distinct rotten egg odour

Most iron removal systems operate on principal of oxidizing the iron from a ferrous, dissolved form to a ferric or undissolved form, followed by filtration. Existing technologies (oxidation by air, chlorine or different oxidation media) allow for the elimination of iron, however there are some limitations depending on the type of iron, its concentration in raw water, and required filtration.

Filter Innovations Iron Removal System (IRS), is an innovative, efficient and cost-effective solution for removing iron from ground water/wastewater/process water.

FII-IRS combines the oxidation process with Filter Innovations' automated controls and separation units, thereby allowing for the removal of all types of iron (ferrous, ferric, bacterial and organic) to bellow 0.3 ppm.

The system can handle iron concentrations from 5 to 100 ppm (on a non-reagent basis) and also helps to reduce other pollutions such as hydrogen sulphide, carbon dioxide, methane, radon, manganese, organic substances.

The FII Deferum IRS is based on a process that can be classified as intensive aeration / degasification followed by filtration. The core of the system is Polymer Floating Media which does not require regeneration or replacement.

Advantages

Treated water quality:

• Reduced Iron content to less than 0.3 ppm.
• Handles Iron concentrations up to 100 ppm
• Continuous removal of iron and dissolved gasses
• Reduction in suspended solids and turbidity

Design/ operational features:

• Small footprint
• Adapts to changing contaminant loadings
• Unique aerator/degasifier removes dissolved gasses and dissolves iron in a single pass
• The filter backwash accounts for only 1% of daily flow
• Filtering media has a life span of over 25 years