Abstract: Waste/industrial effluents containing contaminating amounts of organic and/or inorganic species, for example effluents containing sulfate or sulfuric acid values, or effluents emanating from the production of methionine, are safely and effectively purified in high yield, by first establishing, in a first reaction zone, an axially helically descending flowstream defining a phase of combustion, this phase of combustion comprising ignited admixture of a first oxidizing fluid and a combustible fuel; ejecting the phase of combustion through a port of restricted flow passage to impart an axially symmetrical vortex flow thereto and flash-expanding same into a second reaction zone; introducing effluent to be purified into the axially symmetrical vortex thus formed; and also introducing additional oxidizing fluid into such axially symmetrical vortex, whereby the effluent is disintegrated into a multitude of droplets entrained in unit volumes of the phase of combustion and thermally treated in the second reaction zone.