Abstract: In the installation for decontaminating a liquid effluent contaminated by at least one organic substance, a gaseous combustible is burned in a reactor to produce a flame containing hydroxyl free radicals OH.degree. and oxygen O.sub.2 and that flame is centered on the geometrical axis of the reactor. A helical flow of liquid effluent is produced on the inner cylindrical wall of the reactor to cause a direct contact between the hydroxyl free radicals and the organic substance contaminating the liquid effluent. Having hydroxyl free radicals present, the organic substance is oxidized in liquid phase. The high temperature of the flame enables completion of the oxidation of the organic substance, in liquid phase, by means of the oxygen O.sub.2 present in the flame. At the outlet of the reactor, the liquid and gaseous products are separated; the liquid product is collected while the gaseous product is evacuated.

Abstract: In the process and installation for decontaminating a liquid effluent contaminated by at least one organic substance, a gaseous combustible is burned in a reactor to produce a flame containing hydroxyl free radicals OH.degree. and oxygen O.sub.2 and that flame is centered on the geometrical axis of the reactor. A helical flow of liquid effluent is produced on the inner cylindrical wall of the reactor to cause a direct contact between the hydroxyl free radicals and the organic substance contaminating the liquid effluent. By means of the hydroxyl free radicals, the organic substance is oxidized in liquid phase. The high temperature of the flame enables completion of the oxidation of the organic substance, in liquid phase, by means of the oxygen O.sub.2 present in the flame. At the outlet of the reactor, the liquid and gaseous products are separated; the liquid product is collected while the gaseous product is evacuated.