|Gerry Bulfin reports that iron is one of the earth most plentiful resources, making up at least 5% of the earth crust. In groundwater, iron is usually found as ferrous iron, which is in a dissolved state and may appear clear when first drawn from the tap.|
When the level of iron in water exceeds the 0.3 mg per l limit, the water may have a red, brown, or yellow color and stain laundry and fixtures. The water may also have a metallic taste and an offensive odor. Water system distribution piping can become restricted or clogged, and for homeowners, appliances such as water heaters, dishwashers and washing machines plugged with rust and sediment.
In some applications ion-exchange resin can be used to remove ferrous iron in exchange for sodium, but the most popular and common method is to oxidize the iron to a ferric state and then filter out the precipitated particles.
One way to accomplish this is to use one of many types of oxidizing manganese-based filter media, sold under various brand names. To work properly this media requires one of four oxidants ...
After injection with air, chlorine, permanganate or ozone, the water flows through the iron filter media and oxidation takes place on the manganese dioxide filter media. Periodic backwash and rinses clean the iron filter media of the trapped media.
1. Manganese Dioxide Coated Iron Filter Media
Coated filter media such as manganese, greensand typically contain 1% to 10% manganese oxide in a coating over a mineral substrate such as silica or dolomite.
2. Manganese Dioxide Solid Core Iron Filter Media
Unlike Manganese, greensand which is coated with a manganese oxide coating, manganese dioxide iron filters use a natural mined solid manganese oxide ore in a relatively pure form. Manganese dioxide solid core iron filter media utilize an oxidation-reduction reaction and filtration process like greensand, but at a much higher level of performance.
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