Patent ID: 6048460
Filing Date: 2000-04-11
Classification: B03D,C02F,Y02W

Abstract:
A process for the treatment of waste water in a mixture comprising the waste water and sludge, which comprises,(a) treating the mixture with a first gas in an activation stage to from a suspension, comprising treated waste water and activated sludge, having a bubble rise in a first, natural direction therethrough, while maintaining said activated sludge in said activation stage at a concentration of at least .gtoreq.6 g/l;(b) subjecting said suspension to a pressure-relief flotation treatment at a flow velocity of .ltoreq.0.3 m/sec against said first direction to separate said activated sludge from said treated waste water; and(c) additionally treating said suspension with a second gas by means of a gas-treatment apparatus to form a gas treated suspension which is subjected to said flotation treatment; wherein said gas treated suspension is taken off at the bottom of said gas-treatment apparatus and fed to the flotation.