Kurita Water Industries Ltd.

Akira Iimura

Kouichi Tanaka

Shigeru Sato

Yutaka Yoneda

Kenji Kowata

Naohiro Nagai

Kazuhiko Tsunoda

Urara Usui

Aya Sakaguchi

Hideo Otaka

The invention provides a bactericidal/algicidal method including adding an oxidant-based bactericidal/algicidal agent and a stabilizer therefor to a target water system, characterized in that the amount of combined chlorine or the stabilizer in the water system is controlled by generating free residual chlorine in the water system, and a bactericidal/algicidal method including adding an oxidant-based bactericidal/algicidal agent and a stabilizer therefor to a target water system, characterized in that the amount of the oxidant-based bactericidal/algicidal agent added is controlled so that the concentration of total residual chlorine in the water system falls within a predetermined range, and the amount of combined chlorine or the stabilizer is controlled so that the concentration of free residual chlorine in the water system falls within a predetermined range. An object of the present invention is to provide a bactericidal/algicidal method including adding an oxidant-based bactericidal/algicidal agent and a stabilizer therefor to a target water system for bactericidal/algicidal treatment, wherein the amount of combined chlorine or the stabilizer is controlled, and the amount of the oxidant-based bactericidal/algicidal agent added is controlled, which method realizes effective utilization of the stabilizer, to thereby reduce the amount of the stabilizer employed and to reduce COD and the amount of nitrogen derived from the stabilizer, and which method does not require a special control apparatus for in-line mixing as described above.

Bactericidal/algicidal method

An agent for preventing scale formation and a method for preventing scale formation include a polymer which has at least 50% of N-vinyl formamide units or N-vinyl acetamide units and a phosphorus compound added to water in a cooling water system, a boiler water system, or the like. The scale preventing agent and scale preventing method of the present invention are effective in preventing the adherence of various types of scales which are generated in cooling water systems, boiler water systems, and the like. In particular, the present invention is effective in preventing the adherence of silica and calcium scale.

Scale inhibition agent and method for using same

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Tokyo, Japan

Akira Iimura