Process for purification of effluent

摘要

A process for the purification of effluent, in which the effluent to be purified is first introduced into a high-loaded activation stage operated as an adsorption stage, then is passed through an intermediate clarifier with sludge offtake and subsequently introduced into a low-loaded stage to which a final clarification stage with sludge offtake is connected. Microorganisms work in the adsorption stage. The sludge is maintained in the initiation phase by means of the sludge takeoff from the intermediate clarification stage. Nitrification and subsequently denitrification can be carried out in the low-loaded stage. Sludge from the intermediate clarification stage can be reintroduced as recycled sludge into the adsorption stage, and sludge from the final clarification stage can be re-introduced as recycled sludge into the low-loaded stage. Also excess sludge is drawn off and thickened. The effluent is first treated in the adsorption stage under optionally-anaerobic conditions and before it flows out into the intermediate clarification stage is treated under aerobic conditions. The turbid water from sludge thickening and sludge de-watering is treated with precipitating agents before it is re-conveyed to the inflow of the filter plant.