| abstract |
(57) [Summary] [Problem] If high concentration operation is performed and chemicals are not used, Alternatively, the present invention provides a water treatment method and apparatus for an open circulating cooling water system which is used at a minimum to prevent corrosion and scale. SOLUTION: In the water treatment method of the open circulation cooling water systems 1 and 3 in which cooling water is circulated 2 and 4, a high concentration operation is performed by not discharging or reducing the amount of discharged water, and the cooling water system is used. the part of the circulating cooling water desalted 8, the circulating cooling water in the cooling water system, pH 7.5 to 9.0, the total silica concentration 200mg-SiO 2 / L or less, magnesium hardness (mg-CaCO 3 / L) and total silica concentration (mg-S iO 2 / L) is circulated without adjusting the product to be 4000 to 40000, and the desalting treatment is carried out by using a strongly acidic cation exchange resin, or a strongly basic cation exchange resin and / or a strongly basic cation exchange resin. Alternatively, it can be carried out using a weakly basic anion exchange resin, and an anticorrosive or a scale inhibitor can be added to the circulating cooling water. |