Method of treating a cooling circuit water contaminated with organic substances and inorganic particles

A method of treating cooling circuit water of industrial plants (2), in particular of a hot rolling mill (2), contaminated with organic substances and inorganic particles, comprising the following steps:

• a) separating the organic substances and the inorganic particles from the cooling circuit water so as to obtain a precleaned cooling circuit water;
• b) cooling the precleaned cooling circuit water by an open cooling tower (11) so as to obtain a cooled precleaned cooling circuit water;
• c) desalinating at least a partial volume flow of the cooled precleaned cooling circuit water by an at least one-stage desalination plant (14) so as to obtain a cleaned cooling circuit water;
• and
• d) adding bacteria capable of degrading organic substances present in the cooling circuit water, wherein the bacteria are added to the cooling circuit water before the separation in accordance with step a), before the cooling in accordance with step b) and/or before the desalination in accordance with step c), so as to form a biological cleaning stage.

A plant (1) for treating cooling circuit water of industrial plants (2), in particular of a hot rolling mill (2), contaminated with organic substances and inorganic particles, comprising:

• a) a separation device (5) for separating the organic substances and the inorganic particles from the cooling circuit water in order to obtain precleaned cooling circuit water;
• b) an open cooling tower (11) through which the precleaned cooling circuit water can be cooled;
• c) an at least one-stage desalination plant (14), by means of which at least a partial volume flow of the cooled precleaned cooling circuit water can be desalinated, in order to obtain cleaned cooling circuit water;
• and
• d) a dosing device (16, 17, 18, 20) for adding bacteria capable of degrading the organic substances present in the cooling circuit water, wherein the dosing device (16, 17, 18, 20) is arranged upstream of the separation device (5), upstream of the cooling tower (11) and/or upstream of the desalination plant (14), so as to obtain a biological cleaning stage.