Abstract: The invention concerns a method for purifying aqueous effluents, in particular polluted water, by catalytic oxidation using a three-phase reactor comprising two communicating chambers. The invention is characterised in that it consists in: maintaining the catalyst suspended and continuously circulating it between the two chambers of said reactor, by entrainment under the effect of carrier gas injected into one of said chamber, and in oxidizing the pollutants in contact with the in the other chamber, by injecting a reactive oxidizing gas in said other chamber.

Abstract: A mixed culture reactor biologically removes organic pollution and nitrates by the anoxic route. The reactor includes a central stirred section having a lower part in which biological treatment of supplied raw water takes place. The central reactor section contains a suspension of an attached biomass of low concentration, in the order of a few grams per liter. At least one propelling screw is positioned within a jacket that is coaxially located in the reactor central section to ensure the circulation of the water to be treated. The water to be treated circulates in one direction within the jacket and in an opposite direction outside the jacket. The speed of circulation is selected so that bioparticles remain in suspension within the reactor central section. A release zone is located externally of the reactor central section and communicates with a lower part thereof.