METHOD FOR TREATING WASTE WATER IN A BIOLOGICAL SEWAGE PLANT AND DEVICE APPROPRIATE THEREFOR

摘要

The invention relates to a known method for treating waste water in a biological sewage plant. The waste water is subjected to a bacterial metabolism in a biological treatment stage. The waste water is subsequently extracted from sludge in a partition stage and is supplied to a thickening stage. At least one part of the sludge of the partition stage or the thickening stage is subjected to an oxidative ozone treatment and is at least partially supplied back to the biological treatment stage, whereby said part is the return-sludge. The aim of the invention is to provide a cost-effective method for the ozone used, whereby said method has a high coefficient of utilisation and is based upon the known method. To this end, the ozone treatment comprises a treatment phase wherein ozone-containing return-sludge is subjected to a pressure burden. A device being appropriate for carrying out said method is provided with a biological reactor (3) for receiving and biologically treating waste water. An ozone treatment plant (2) is used for subjecting return-sludge to an oxidative ozone treatment. A supply device (14; 15) for supplying ozone-containing gas into the return-sludge is provided. A pressure treatment chamber (8) is arranged downstream in relation to said supply device. Ozone-containing return-sludge is subjected to a pressure burden in the pressure treatment chamber.