The problem of dumping manure into the ocean - from September 1999 to the 2020s

The problem of dumping manure into the ocean - from September 1999 to the 2020s

In FY1998, 2.12 million kiloliters of human waste was dumped into the ocean in Japan. This amount is equivalent to the annual discharge of about 800,000 people, and marine pollution has become serious in Tokyo Bay, Osaka Bay, Ise Bay, and other areas. The Ministry of Health and Welfare promoted guidance to municipalities on the development of treatment plants and the establishment of appropriate treatment systems.

Situation in the 2010s
In the 2010s, environmental protection awareness increased and the reduction of ocean dumping accelerated. In Tokyo, the sewerage system penetration rate exceeded 98%, and almost all waste is now treated on land. In Osaka City, biogasification technology was introduced, establishing a model for utilizing human waste as an energy resource. In rural areas, septic tanks manufactured by EBARA Corporation have played an active role, and appropriate treatment has progressed even in areas where sewage systems are not yet in place. On the other hand, the cost burden of land-based treatment in Hokkaido and remote island regions became an issue, and support among local governments was discussed.

Current Status in the 2020s
By the 2020s, ocean dumping of human waste will be almost completely eliminated, significantly reducing the burden on the marine environment. Under the guidance of the Ministry of Health and Welfare, Kawasaki Heavy Industries' biogas plant and EBARA Corporation's advanced treatment facility were introduced, improving treatment capacity in each region. 2023 saw the Ministry of the Environment announce that zero ocean dumping had been achieved. As a result of the nationwide spread of the system, human waste is reused as fertilizer and biogas, contributing to the creation of a recycling-oriented society.

Figures and Results
The amount of ocean dumping, which was 2.12 million kiloliters per year in 1998, was less than 100,000 kiloliters by the mid-2010s and almost zero by the early 2020s. Technological innovations and policy achievements have had a positive impact on the fishing and tourism industries in coastal areas.

Challenges and Prospects
Maintenance of land-based treatment facilities continues to be a challenge in remote islands and mountainous areas, and the introduction of mobile treatment facilities is being considered. Efforts are also underway to expand the use of recycled resources from human waste treatment and to utilize biogas supply as a local energy source. Future efforts are expected to include marine environmental protection not only domestically but also in cooperation with neighboring countries.