METHOD FOR TREATING CHROMIUM PRESENT IN EFFLUENTS, AND CORRESPONDING EQUIPMENT

摘要

The present invention relates to a method for reducing the chromium content, particularly hexavalent chromium content, present in a liquid effluent, referred to as "initial effluent" (1), loaded with solid particles. Said method includes at least one reducing step (9) whereby a weak organic acid (10) is added to the initial effluent in an amount sufficient to reduce the hexavalent chromium, present in the initial effluent, to a lower valence, i.e. trivalent chromium. Said step is followed by a step for discharging the resulting treated liquid effluent, referred to as the "final effluent". Said method also includes a step for collecting, at least by settling, the solid particles present in the initial effluent and a reducing step (9) that is carried out after adjusting (12) the pH of the initial effluent to a pH value that is less than the initial pH of the effluent while being compatible with discharging the final effluent at said pH value. The invention also includes equipment for implementing the method.