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 1990s in Japan, inner bays such as Tokyo Bay, Ise Bay, and the Seto Inland Sea were suffering from serious water pollution. With economic growth and urbanization, the inflow of industrial and domestic wastewater increased, and the COD (chemical oxygen demand) values showed no signs of improvement. In particular, the excessive inflow of nitrogen and phosphorus led to eutrophication, causing red and blue tides, which had a tremendous impact on the fishing industry and ecosystem. In response to this situation, the Environment Agency formulated the Fifth Total Emission Regulations, adding nitrogen and phosphorus to the existing COD regulations.

This policy forced a wide range of industries, including the chemical industry, the food processing industry, the livestock industry, and sewage works, to take action. While this was a heavy burden on industry, it also provided an opportunity to spur technological innovation. Sewage treatment plants introduced advanced treatment technologies, especially denitrification and biological phosphorus removal. The "A2O method" and the "oxidation ditch method," which improved the activated sludge method, efficiently removed nitrogen and phosphorus, and greatly improved the quality of discharged water. The coagulation sedimentation method and high-performance membrane separation technology were also introduced, and played a part in the reuse of treated water and the recycling of water resources.

In addition, phosphorus recovery technology was developed in industry, and attempts to reuse phosphorus as fertilizer spread. This is a movement to simultaneously reduce waste and secure resources by extracting phosphorus from sewage sludge and wastewater and incorporating it into the resource cycle. This technological advancement is not merely a response to environmental regulations, but a major step toward the realization of sustainable production and a recycling-oriented society.

The Rio Earth Summit in 1992 made "sustainable development" a national policy issue in Japan, and the adoption of the Kyoto Protocol in 1997 encouraged the trend toward tighter environmental regulations. The 1999 tightening of total emission limits was a symbolic measure that responded to this international trend and shifted environmental administration from "reducing quantity" to "improving quality. It was during this period that attempts to protect coastal seas and pass on blue waters to the next generation were steadily launched.