Abstract: The regeneration of active carbon onto which one or more organic substances may be adsorbed is achieved by means of a photodegrading process catalyzed by a semiconductor.

Abstract: A method for reducing industrial or urban effluent COD is described, comprising treating said effluents with an aqueous solution of alkaline and/or ammonium salts or humic acids perpared by the dry oxidation of coal with oxygen or oxygen/nitrogen mixtures at a temperture of between 120 and 350.degree. C. at an oxygen partial pressure of between 0.1 and 10 ata for a contact time of between 15 and 600 minutes, followed by extraction of the crude oxidation product with an alkaline and/or ammoniacal solution, characterised in that said aqueous solution is fed into effluent, the pH of which has been previously adjusted to between 1 and 3.5, to the extent that the humic acid salts which exhibit flocculating action are in a concentration of less than or equal to 2000 mg/1 of effluent.

Abstract: A process is disclosed for the removal of metals from waters containing them, comprising the treatment of the waters with an aqueous solution of alkaline salts of humic acids, which is characterized in that said solution is obtained by the dry oxidation of coal by oxygen or mixtures of oxygen and nitrogen, in particular air, and the subsequent extraction of the raw oxidation product by an alkaline solution, and that said aqueous solution is added to into the waters as such, wherein the humic acids salts perform a flocculating action, with the end pH being preliminarily to a value comprised within the range of from 1.5 to 5.5.