METHOD FOR BIOLOGICAL TREATMENT OF CONCENTRATED WASTE WATER WITH ACTIVE SLUDGE, INCLUDING TREATMENT STEPS IN ANOXIC, ANAEROBIC AND AEROBIC CONDITIONS Russian patent published in 2025 - IPC C02F3/30 

FIELD: water treatment.

SUBSTANCE: invention relates to the field of technologies for biological treatment of waste water. Initial waste water is fed into reservoirs with active sludge, in which anoxic, anaerobic and aerobic treatment conditions are successively provided. Waste water is denitrified under anoxic conditions. Under anaerobic conditions dephosphatation is carried out and nitrification is carried out under aerobic conditions. Then, part of the sludge mixture is directed as part of a nitrate recycling into a tank with anoxide conditions, thereby providing denitrification in it. Other part of the sludge mixture is separated into purified waste water and active sludge on a phase separator. Purified waste water is discharged. Active sludge is directed as part of active sludge recycling into a tank with anoxide conditions. Consumption of nitrate recycling must be carried out taking into account the required coefficient of recycling R in relation to the initial consumption, which is determined by the formula R=(N_tot.in.-N_NH4perm.)/N_tot.perm., where R is the recycling coefficient, N_tot.in. is concentration of total nitrogen in initial waste water, N_tot.perm. is permissible concentration of total nitrogen in treated waste water, N_NH4perm. is permissible concentration of ammonium nitrogen in treated waste water, wherein concentrations of substances presented in the formula are measured in "mg/dm³".

EFFECT: providing the required degree of purification of concentrated waste water with concentration of ammonium compounds in the initial water of more than 50 mg/dm³ at a rate of discharge into the water body of waste water with concentration of total nitrogen at level of 9-10 mg/dm³ while reducing the number of recycles of the sludge mixture.

5 cl, 3 dwg, 1 tbl