Post-purificn. system for waste water, following activated sludge process

摘要

A group of vessels carries out: preliminary denitrification; nitrification; clarification; recirculation of activated sludge and nitrified waste water. Recirculation is induced with the air of pneumatic energy, the air being introduced at one or more locations within the vessel unit. Processing proceeds in an alternating series of aerated and non-aerated vessel units. The tank unit in which the processes take place is also claimed. In the first non-aerated vessel, waste water is mixed with activated sludge, constituting a denitrification stage. From here, the next vessel is an aerator, where nitrification takes place and then there is a non-aerated clarification zone follows. The recycled activated sludge and nitrified waste water, are sent to an activated sludge aeration region. This and the nitrified waste water are recirculated into a non-aerated tank unit. Waste water - activated sludge mixture from the non-aerated vessel is introduced in the lower region of the aerated vessel unit. Waste water - activated sludge mixture from the aerated vessel enters the upper region of the non-aerated vessel. Air is blasted in, as fine bubbles for aeration, also achieving density reduction and a degree of lift, to move the fluid.