Process for purifying waste water

摘要

Process for purifying waste water, in particular municipal waste water, with the aid of an activation plant, which activation plant has an activation stage and, provided upstream of this, a preclarification (if required, in addition a screen and an aerated sand trap) and, connected downstream, a secondary clarification. The untreated waste water is supplied to the activation plant via a sewage system having at least one sewer. Activated sludge is drawn off from the preclarification. The sewage system is used as a high-loading adsorption stage. For this purpose, activated sludge from the preclarification, which is now functioning downstream of the adsorption stage as intermediate clarification, is introduced into the sewer (or into the sewers) at a distance of more than 300 m upstream of the activation stage via a return pipe. The activation stage is operated as a low-loading stage. <IMAGE>