Manganese removal physical-chemical way
|As for iron, the origin of manganese, in water, is at the same time natural (dissolution of the reduced form Mn2+) and industrial (mining, the iron and steel industry, etc). The same goes for its removal from water. Manganese does not present a danger to human health, nor for the environment but it is unpleasant. In fact, the water gets a black color and a metallic taste. |
Similar to iron, the manganese removal by physical-chemical way, can be carried out by the oxidation of Mn2+ in Mn4+, which precipitates then in manganese dioxide (MnO2). The precipitation is then separated from water by filtration on sand.
The only difference (with the iron), is in the reagent used. Indeed, oxidation by oxygen is in many cases not sufficient for manganese at neutral pH. Stronger oxidants can be used in complement such as chlorine dioxide (ClO2), chlorine (Cl2), potassium permanganate (KMnO4) or ozone (O3).
In the same way for iron, manganese can be removed by biological way. There are bacteria which take their energy from the oxidation of manganese and which require a water with specific conditions to have an optimal activity of the micro-organisms. However, even if it is possible to carry out in the same time the iron and manganese removal by physical-chemical treatment, the same doesn’t go for the biological way. In fact, the iron and the manganese specific bacteria need different environmental conditions.
|New: Iron removal by physical-chemical way|