BIOCHEMICAL METHOD OF CLEANING WASTE WATER Russian patent published in 2008 - IPC C02F9/08 C02F3/12 C02F1/36 C02F103/20 

FIELD: chemistry.

SUBSTANCE: invention pertains to biological methods of cleaning household, agricultural and industrial waste water. The method involves aerobic biooxidation of waste water pollutants in an aerotank in the presence of active sludge, part of which is treated using ultrasound, with subsequent settling of the sludge suspension in a settling tank, outlet of cleaned water from the treatment facilities, and return of the circulating sludge into the aerotank. Before entering the aerotank, a mixture of supplementary active sludge (mixed liquor) aerobically stabilised and treated using ultrasound, is continuously added to the waste water in the primary settling tank. Ultrasound treatment mode: - frequency - 22 KHz, intensity - 6-8 W/cm², time - 0.5-2.0 min. Volume of the mixed liquor is 1-2% of the volume of the circulating sludge with ratio of the supplementary active sludge to the aerobically stabilised active sludge ranges from 1:1 to 1:2.

EFFECT: higher degree of purification of concentrated and complex composition waste water, containing hard to oxidise xenobiotic and toxicants; lower expenditure of biogenic elements.

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