FIELD: chemistry.
SUBSTANCE: invention relates to methods of treating sewage water, containing ions of heavy metals and sulphates in high concentrations, for example sewage water from electroplating industry. To realise the method, sewage water is classified according to overall content of heavy metals to dilute (≤2 mmol/l) and concentrated (≥2 mmol/l) solutions. Dilute sewage water is fed into a bioreactor, and concentrated sewage water is mixed with the stream from the bioreactor and containing biogeneous sulphide. Ions of heavy metals are precipitated in form of sulphides and are then separated together or individually. Part of sewage water after removal of the residue of metal sulphides is fed back into the bioreactor. If sulphates in the water exceed the standard value, the sewage water is directed into the drainage or in the presence of insufficiently diluted solution of sewage water.
EFFECT: prevention of bacteria intoxication, flexible technology of treating concentrated metal-containing sewage water, cheap technology of reducing concentration of sulphates in sewage water, selective precipitation and recycling of heavy metals.
8 cl, 2 dwg, 1 ex, 1 tbl
