Abstract: The present invention relates to a reactor for biological purification of pollutant-containing water in a closed vessel by means of loop operation. This vessel contains, disposed vertically and concentrically with respect to its jacket and to each other, an insertable pipe that is open at both ends, into which a nozzle projects for the purpose of supplying the water-gas-biomass mixture to be purified, and a guide pipe that is open at both ends and that forms an inner annulus with the internal insertable pipe and an outer annulus with the reactor jacket. This guide pipe projects above and below the ends of the insertable pipe. A deflector plate is mounted below the insertable pipe but inside the guide pipe, so that part of the biomass-water mixture is deflected back into the inner annulus. A conically shaped sedimentation chamber is disposed in the lower part of the reactor.

Abstract: The invention relates to an installation for aerobic biological purification of pollutant-containing water, which installation consists of an axial-flow submerged reactor and a sedimentation tank for separation of the biosludge from the purified water. The reactor is a pipe containing a two-stage activated-sludge chamber, which pipe contains (a) a first activated-sludge stage in which a driving-jet nozzle is disposed at the downstream end for the dispersion of the air and the microorganisms in the waste water to be purified, and (b) a second activated-sludge stage in which internals are disposed for homogeneous dispersion of the gas bubbles and the microorganisms as well as for immobilization thereof.