Environment The Fight to Restore the Blue Ocean - Trajectory of the Tightening of Total Water Quality Regulations 1999

Environment The Fight to Restore the Blue Ocean - Trajectory of the Tightening of Total Water Quality Regulations 1999

In the late 1990s, Japan's inner bays were facing serious water pollution. In Tokyo Bay, Ise Bay, and the Seto Inland Sea, COD levels remained high due to increased industrial and domestic wastewater discharges, and excessive inflows of nitrogen and phosphorus led to eutrophication, resulting in frequent red and blue tides that caused major damage to the fishing industry and ecosystem. In response to this situation, the Environment Agency formulated the Fifth Total Emission Regulation, which newly regulates nitrogen and phosphorus in addition to the existing COD. This new regulation forced a wide range of industries, including the chemical industry, food processing, livestock breeding, and sewage works, to take action, but it also provided an opportunity to promote technological innovation.

In sewage treatment plants, denitrification and biological phosphorus removal were developed, and advanced treatment using the A2O method and the oxidation ditch method became widespread. In addition, coagulation sedimentation and membrane separation technologies were introduced, which helped to secure water for reuse and recycling. Phosphorus recovery technology was also put to practical use in industry, and attempts to reuse phosphorus as fertilizer spread, simultaneously promoting waste reduction and resource recycling.

The tightening of regulations in 1999 was a symbolic shift in Japan's environmental policy from "reduction of quantity" to "improvement of quality," and was a milestone toward the restoration of coastal waters and a recycling-oriented society. It was a milestone in Japan's efforts to revitalize coastal waters and create a recycling-oriented society.