Manganese in Water

Manganese in water (Mn+4, Mn+2) is present, because in part, many soils and sediments as well as in rocks whose structures have been changed by heat and pressure. Manganese is used in the manufacture of steel to improve corrosion resistance and hardness. Manganese is considered essential to plant and animal life and can be derived from such foods as corn, spinach, and whole wheat products. It is known to be important in building strong bones and may be beneficial to the cardiovascular system. Manganese in drinking water may be found in deep well waters and some of these water supplies have manganese levels in water as high as 2 - 3 mg/l. It is hard to treat manganese in water because of the complexes it can form which are dependent on the oxidation state, pH, bicarbonate-carbonate-OH ratios, and the presence of other minerals, particularly iron. Manganese levels in drinking water higher than 0.05 mg/l cause manganese deposits and staining of clothing and plumbing fixtures. The stains are dark brown to black in nature. The use of chlorine bleach in the laundry will cause the stains to set. The chemistry of manganese in water is similar to that of iron. High levels of manganese in drinking water produce an unpleasant odor and taste. Organic materials can tie up manganese in the same manner as they do iron, therefore destruction of the organic matter is a necessary part of manganese water treatment.  
 
Manganese Water Filters and Treatment - Treatment and filtering of manganese from water can be done by ion exchange (sodium form cation - softener) or chemical oxidation - retention - filtration. Removal with a water softener dictates that the pH be 6.8 or higher and is beneficial to use countercurrent regeneration with brine make-up and backwash utilizing soft water. It takes 1 ppm of oxygen to treat 1.5 ppm of manganese. An effiective manganese water filter, Greensand filter, with potassium will remove up to 10 ppm if pH is above 8.0. Birm filter with air injection will reduce manganese if pH is 8.0 to 8.5. Chemical feed (chlorine, potassium permanganate, or hydrogen peroxide) followed by 20 minutes retention and then filtered with birm, greensand, carbon, or Filter Ag will also remove the manganese in drinking water.