PROCESS FOR TREATING WASTE WATER TO REMOVE SULFATE IONS Russian patent published in 2008 - IPC C02F1/66 C02F1/58 C02F103/16 

FIELD: waste water treatment.

SUBSTANCE: invention relates to reagent treatment of waste and natural waters to remove sulfates and can be used in mining and chemical industries as well as to treat electrolytic effluents from engineering plants. Process comprises neutralization of waste water and adding amorphous-structure aluminum hydroxide reagent recovered from acid solution of aluminum salt. Neutralization is conducted to achieve pH 12.2-12.4, after which water is clarified. Reagent is added stepwise, first portion constituting 10-25% and the rest added after mixing it with water. Water is then further neutralized to pH 12.7-13.0 while being continuously stirred until sulfate ions are precipitated into solid phase.

EFFECT: enabled purification of waste waters highly polluted with sodium sulfate to limited sulfate ion concentration not higher than 100 mg/dm³ and not higher than 600 mg/dm³ when discharging waste water to fish farming reservoir and to household water supply, respectively.

2 cl, 1 tbl, 6 ex