Nkk Corporation

Satoru Udagawa

Satoru Ando

Toyofumi Watanabe

Shinichi Endo

Masaki Abe

Masaya Morita

Yukimitsu Shiohara

Toshiaki Tsubone

Yasuhiro Matsuki

Kei Baba

Tatsuo Takechi

Jun Miyata

Masahisa Tanabe

Akimasa Kido

Phosphorus in wastewater is removed by using an apparatus including a settling tank, an anaerobic tank, an aerobic tank, and a final settling tank. Nitrogen in wastewater is removed by using an apparatus including a settling tank, an anaerobic tank, a nitrification tank, and a final settling tank.

Apparatus for wastewater treatment

A surface treated steel sheet comprises: a steel sheet containing C, Si, Mn, P, S, Ni, Ti, Cu and B; a diffused alloy layer containing Fe, Ni, and P; and a zinc coating layer formed on the diffused alloy layer. A method for producing a surface treated steel sheet comprises the steps of: preparing a steel sheet; coating the steel sheet with a Ni-P coating layer; heat-treating the steel sheet coated with the Ni-P coating layer; and forming a zinc coating layer on the diffused alloy layer.

Surface treated steel sheet

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Yokohama, Japan

Satoru Udagawa