Method of treating waste water with jet nozzles

A process for the treatment of waste water in activated-sludge systems by means of one or more aerating nozzles which comprises introducing from a nozzle or nozzles submerged in a body of waste water and activated sludge in a reservoir a gas stream of air or a high-oxygen gas or parallel, contiguous streams of air or a high oxygen gas and a propellant liquid into a small impulse exchange tube positioned contiguous to and axially downstream of said nozzle or nozzles, said nozzle or nozzles being positioned asymmetrically to the center of gravity of a transverse, cross sectional plane of said body of waste water and activated sludge and near the bottom of said body, producing a directional flow from the environment of the nozzle or nozzles in the reservoir by impulse exchange between the mass flow leaving the nozzle or nozzles at an average impulse density of from 10.sup.3 to 10.sup.4 N/m.sup.2 and the mixture of waste water and activated sludge in said body flowing more slowly at an average impulse density of from 50 to 10.sup.3 N/m.sup.2, and superimposing on said directional flow a rotary motion by the column of ascending bubbles emerging from the impulse exchange tube or tubes asymmetrically to said center of gravity and near the bottom of said body to provide a screw type flow of the mixture of waste water and activated sludge.