To provide a method for treating an open circulating cooling water system capable of preventing a waste of a supply water, saving a water using amount and stabilizing water quality of a circulating cooling water.
The method for treating an open circulating cooling water system comprises the steps of taking out a part of the circulating cooling water A from the open circulating cooling water system 19, filtering the taken-out cooling water by using a filter 41, and then returning the filtered water to the original open circulating cooling water system 19. The method further comprises the steps of back-washing the filter 41 at a time of predicting clogging or generating the clogging or at the time in which electrical conductivity of the cooling water A becomes a preset value or more in such a manner that as a back washing water, the cooling water A is used, draining the back washing water out of the system 19, and supplying a supply water B having lower electrical conductivity than that of the set value corresponding to the back washing drain discharged out of the system 19.
ITO MAMORU
KOMATA HIDENORI
