Patent ID: RE40565

Claim:
Method of purifying waste water charged with organic materials, the method including a step in which the waste water remains in a biological treatment system, referred to as the main biological treatment system, in which said organic materials are degraded by micro-organisms to produce sludge, some of the sludge being subjected to ozonation combined with mechanical stirring before it is sent to the main biological treatment system, the sludge subjected to ozonation in this way being referred to as treated sludge, wherein during the mechanical stirring step sufficient mechanical energy is imparted to said treated sludge to attack the cell walls of the bacteria and other micro-organisms contained in the treated sludge, this mechanical energy being from 50 kJ/kg to 3,000 kJ/kg of dry material in the treated sludge, and wherein from 0.001 g to 0.2 g 0 . 02 g of ozone per gram of dry material in the treated sludge are consumed during the ozonation step.