Abstract: A method of biological purification of waste water by removing organic contaminants therefrom by activated sludge in two purification stages is proposed. The primary stage involves mixing waste water with activated sludge, aerating the mixture and separating recyclable sludge and sludge water. The recyclable sludge is regenerated and fed for mixing with waste water. At the secondary stage the sludge water of the primary purification stage is aerated and residual activated sludge is removed therefrom. The recyclable sludge delivered for regeneration is divided into two flows one of which is fed directly for regeneration, whereas the other is compacted prior to regeneration to be mixed with the first for joint regeneration. An invariable ratio between the amount of organic contaminants carried by incoming waste water and activated sludge is continuously maintained at the first purification stage. An aeration tank for carrying out the proposed method comprises mixing vessels of the primary and secondary stages.

Abstract: An aeration tank for purifying sewage water by activated sludge comprising a mixing vessel communicated, according to the principle of communicating vessels, with a sludge separator, and a regenerator of activated sludge communicable with an outlet or recyclable sludge of the sludge separator and with the mixing vessel for feeding thereinto regenerated activated sludge. The mixing vessel is provided with at least one vertically arranged blade-type aerator having a suction tube an inlet end of which communicates with the regenerator, whereas an outlet end of which has a funnel accommodating the blades of the aerator. The sludge separator is equipped with a regulator of dynamic level of sludge medium, the upper edge of the funnel being positioned substantially above the dynamic level of the sludge medium in the mixing vessel.

Abstract: An aeration tank comprising a mixing vessel having starting and end zones. The mixing tank has water-jet aeration columns and communicates with a sludge separator provided with an outlet of recyclable sludge communicable with a circulation pump connected through a pressure pipe line to the aeration columns. There is also provided a regeneration chamber communicated with the outlet of recyclable sludge of the sludge separator and with the end zone of the mixing vessel, and a chamber for deoxygenation of the sludge medium having an inlet of waste water and communicating with the regeneration chamber and with the starting zone of the mixing vessel. A suction pipeline of the pump communicates with the chamber for deoxygeneation of the sludge medium and with the starting zone of the mixing vessel.