According to data from the Ministry of the Environment,^*1 in Japan in the Edo period, which spanned from the 17th to the mid-19th century, a cycle operated in which night soil and food waste generated in the city was passed on to farmers who used it as fertilizer in their fields, and then the rice and vegetables grown in those fields were supplied back as food for the townspeople. As night soil and food waste did not accumulate in the urban areas, Edo (modern-day Tokyo) was a hygienic city, and society at the time is regarded as having been a sound material-cycle society.

As we moved into the 21st century, concerns arose in the international community about the depletion of fossil fuel resources and shortages of food and water due to urbanization and population increases. In recent years, as we work toward a new sound material-cycle society in order to protect our limited resources and the environment, Japan has been focusing on all kinds of potential hidden in sewerage lines, such as night soil, a resource contained in sewage was at one time reused as fertilizer for fields.

In 2005, a new concept of sewerage was set out, giving them a new view as the route toward a sound material-cycle society which creates healthy water and resource cycles. Under this vision, sewerage would serve not only to clean water, but also to regenerate and utilize water and resources from sewage, with sewerage facilities being revived to achieve this. In 2014, the New Sewage Line Vision was formulated with the aim of “sustaining and evolving natural resource cycles,” focusing on how to make the natural resource cycles sustainable in light of the operational challenges of the sewerage industry.
Amidst this wave of change, Kubota is developing technologies that save huge amounts of energy at sewage treatment facilities, and technologies that recover and reuse valuable resources from sewage sludge, such as phosphorus, among other initiatives. At Kubota, we are working to maximize the potential of sewage lines and doing our part to build a sound material-cycle society.