Huge investments for water and waste water management and ambient water environment improvement have been conducted for many years in economically developed countries including Japan. The investment for water supply, on-site and centralized municipal waste water treatment systems (WWTSs), river...

Water quality conditions in the Yamato-Gawa River, Japan, in 1963 might be Pareto optimum because biological oxygen demand (BOD) concentration was smaller than the BOD criteria, 5 mg l-1, which was determined in 1970, however, water quality deterioration in 1963-1970, up to 22 for average or 32...