Method for purifying waste water, and purification plant for carrying out said method

Abstract

The invention relates to problematic waste water with highly concentrated impurities, for example seepage water from a refuse dump, which is anaerobically degraded in an anaerobic treatment zone (digester) and the digested sludge arising therefrom is mechanically de-watered. Simultaneously, communal waste water is purified in a purification plant containing an aerobic treatment zone, wherein advanced nitrification/denitrification and/or phosphorous elimination can be activated/started by recycling oxygen and nitrate rich water and sludge back into the inlet area. In the aerobic purification zone, the excess digested sludge, in which a large part of the AOX load of the communal waste is incorporated, is mechanically de-watered and is discharged into the anaerobic purification zone (digester), in order to degrade the AOX load by decomposition. The degree of dewatering of the excess sludge is controlled according to the amount of problematic waste water to be processed. The filtrate obtained from the dewatered sludge, which contains the greater part of the nitrogen load, is introduced into the aerobic purification zone in the purification plant and is subjected to nitrification/denitrification therein.

Dependencies are inferred from the claim text.