METHOD FOR PURIFICATION OF SEWAGE WATERS Russian patent published in 2015 - IPC C02F3/30 C02F3/02 C02F101/16 

FIELD: chemistry.

SUBSTANCE: method includes biological purification of sewage waters in aerotank, which has successively alternating anaerobic, aerobic, anoxide, second aerobic zones, external recycle of return sludge from secondary clarifier into anaerobic zone. Compressed air is supplied into aerobic and second aerobic zones, with initial sewage water being supplied into anaerobic and anoxide zones. After second aerobic zone sewage waters are supplied into second anoxide zone and third aerobic zone. Internal recycle is realised from third aerobic zone into anoxide zone. To realise the method initial sewage water is supplied in ratio 50÷60% into anaerobic zone, 30÷40% into anoxide zone and 0÷20% into second anoxide zone. Return active sludge after settling is pumped from secondary clarifier into anaerobic zone in ratio 50÷100% of volume of sewage waters, supplied for purification.

EFFECT: increased degree of purification of sewage waters from nitrogen, phosphorus and organic compounds, intensification of processes of biological purification, increase of oxidative system capacity.

5 cl, 4 dwg