Innovative Treatment of Acid Mine Drainage-The VitaSOFT Process
The VitaSOFT process integrates four biological processes with various chemical processes in order to treat acidic sulphate and metal containing wastewaters, achieving water quality of potable standard.
Sulphates are removed in an active biological sulphate reducing (BSR) process where sulphides and alkalinity are generated, making use of a carbon source such as primary sewage sludge or maize silage. These are used for the precipitation of heavy metals in the feed water, specifically iron.
The remaining sulphides are removed biologically through biological sulphide oxidation to form elemental sulphur, and chemically through iron hydroxide precipitation to form iron sulphide.
Iron sulphide is oxidised in a biological iron oxidising process, regenerating iron hydroxide for use in the sulphide precipitation reaction. A constant source of iron hydroxide is therefore not necessary.
Sufficient alkalinity is generated biologically in the process to remove all the original calcium in the AMD as calcium carbonate after the biological sulphide oxidation process without the addition of an external source of lime. Additional lime is required only for the removal of manganese and magnesium.
The final effluent is polished biologically in a trickling filter for discharge to the environment or for industrial reuse. Alternatively, it can be treated further in a reverse osmosis system to produce ultra pure industrial water or potable water.
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