Iron Removal and Manganese Filter
Iron in water supplies usually exists in either of the following oxidation states:
- a) Divalent Fe+2 which is the soluble form of irons found in water supplies.
- b) Trivalent FFe+3 which is a stable form of irons that is typically insoluble in water.
Mn usually exists in water supplies in the following oxidation states:
- a) In any oxidation state from Mn0 to Mn+4.
- b) Solublemanganousoxide,Mn+2.
- c) Manganic oxide, Mn+4, the stable form of Mn that is insoluble in drinking water supplies.
When iron removal and manganese filter are found in water that has no dissolved oxygen they exist in the reduced soluble forms. These soluble forms are: divalent Fe+2 and manganous oxide, (Mn+2).
Dissolved Fe and Mn are removed from water supplies predominately by oxidation and filtration. The soluble ferrous and manganous forms are oxidized to the insoluble ferric and manganic forms. The insoluble ferric and manganic precipitates are then filtered.
Soluble Fe and Mn cause the following objectionable problems in drinking water supplies. The TWA has established secondary standards of 0.30 mg/l for Fe and 0.05 mg/l for Mn to alleviate these objectionable affects to water consumers and purveyors.
- Metallic and bitter taste and odors.
- Staining of porcelain household fixtures, clothing and swimming pool plaster. Fe causes a reddish color. Mn causes a blackish color. Fe and Mn in combination cause reddish black color.
- Fouling of water softener resins. Water quality decreases and regeneration costs are significantly increased
- Fouling of cooling water systems. Deposition in water heaters.
- Industrial process water contamination such as food, beverage and textile processing and silicon chip manufacturing.