摘要 |
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 of humic acids prepared by the dry oxidation of coal with oxygen or oxygen/nitrogen mixtures at a temperature of between 120 and 350 DEG 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/l of effluent. |