METHOD OF PURIFYING WASTE WATER Russian patent published in 1996 - IPC

FIELD: waste water purification. SUBSTANCE: waste water is purified in two-step process with active sludge with intermediate clarification of purified stuff with active sludge and secondary active sludge-clarification after the 2nd step using recycling of sludge. The 1st step is conducted aerobically as an adsorption process with sludge consumption equal to at least 2 kg per 1 kg of dry stuff in one day or, optionally, as an anaerobic process using preferably procaryotes in working biomass (at least 500 10⁶ germs in 1 cu.cm). The 2nd step is conducted with aeration and sludge consumption less than 0.15 kg per 1 kg of dry stuff in one day. Sludge from secondary clarification process at least partially is transferred into adsorption step. EFFECT: enhanced efficiency of purification. 2 cl, 1 dwg