Abstract: A process for dewatering slimes produced in mining and mineral processing operations whereby wet oxidation at 150.degree.-320.degree. C. renders the solids rapidly settleable. Sufficient oxygen is supplied to meet or exceed oxygen demand. Inorganic solids in the oxidized product are separated and optionally further dewatered to a friable solid. Clarified water is recycled to the mining, mineral processing or other operations, or treated further, or discharged to the environment. Steam resulting from the wet oxidation is utilized in the mining or mineral processing operations.

Abstract: Disinfection of aqueous media contaminated with microorganisms is effected by contacting said media with a gas phase in which a plasma is generated by focused laser radiation. Similarly, wastewaters containing organic susbstances are purified by contacting them with an oxygen-containing gas phase in which a plasma is generated by focused laser radiation which promotes oxidation of the organic substances to innocuous products.

Abstract: A sulfur bearing fuel is wet oxidized in the presence of an alkaline earth metal carbonate, of which the corresponding sulfate is insoluble. Ash and sulfate salt blown down from the wet oxidation are reacted at high temperature with another portion of the same or a different fuel to reduce the sulfate to sulfide. Carbonation of an aqueous dispersion of the sulfide releases hydrogen sulfide which is converted to elemental sulfur. Carbonate precipitates and is recycled.

Abstract: A process for wet air oxidation of liquid or solid combustible materials which are insoluble, immiscible and difficult to suspend in water which comprises injecting said materials directly into the wet air oxidation reactor, thereby producing a regular, safe and trouble-free reaction.

Abstract: A process for purification of waste waters comprising simultaneous treatment with an adsorbent such as powdered activated carbon and oxygen in the presence of activated sludge to effect nitrification, followed by denitrification in the presence of further adsorbent under anaerobic conditions.

Abstract: A method for the improvement of the biological removal of nitrogen from wastewater consisting of the partial oxidation of waste activated sludge and other carbonaceous material generating soluble BOD which may be substituted for methanol as an oxygen acceptor in biological denitrification.