Highly efficient aerating system - for an activated sludge effluent treatment plant, with restricted liquid circulation in aerating tank

摘要

In the purificn. of domestic or industrial liq. effluent, by blowing an oxygen-contg. gas through aerators into an aeration tank contg. bacterial sludge, (i) the aerators, which are situated at the bottom of the aerating tank and fixed to a moving framework are moved continuously by an external force, (ii) the sludge settling on the bottom is brought into suspension again by means of air lift pumps sited at the bottom of the tank and also fixed to the moving framework, (iii) the circulation of the tank contents is inhibited by a specific number of baffles the shape and location of which are such as not to prevent the action of the aerators, the air-lift pumps and the moving framework, while preventing the whole contents of the tank from acquiring the motion of the moving framework, and (iv) a part of the already aerated effluent is supplied via a connecting pipe to a sedimentation tank, while part of effluent sepd. in this tank can be recycled to the aerating tank to regulate the solids content, partic. via a pipe incorporating an air-lift pump. Has a very high aerating efficiency e.g., 3 kg. O2/kWh as compared with only 1.8-2.2 kg. O2/kWh in the best of the known aerators.