In Japan, efforts to improve the water quality and environment of rivers and seas through various water quality regulations have been underway since the 1970s. Furthermore, in the 2000s, there were calls for the formation of a sound material-cycle society through recycling and reuse, and in recent years, there has been an urgent need on a global scale to create sustainable societies by reducing the environmental burden on the earth through energy and resource recycling, decarbonization, and other initiatives. Under such circumstances, the role demanded of sewerage systems is significant. Starting with the improvement of water quality, a great deal of attention is being paid to the recovery of precious resources and energy, as well the effective use of highly treated reclaimed water as a water resource.

In fact, this highly treated recycled water is playing a role in revitalizing the Dotonbori River, the symbol of Osaka, one of Japan's largest cities. Osaka is known as the "City of Water" because of its development supported by water transportation, but like other major cities, as urbanization progressed, water pollution from factories and domestic wastewater became more serious. For the people of Osaka, their beloved river was a familiar part of their lives, but this pollution threatened to bring an end to this harmonious coexistence. To stop this from happening, in 2014, Osaka launched an initiative to bring back the livelihoods and prosperity that once existed alongside the water.

Focusing on improving water quality, the city has installed sluice gates to take in water from relatively clean rivers, dredged up mud from the river bottom, and built large storage pipes that can temporarily store large amounts of rainwater to prevent sewage from flowing into the river. In addition, plans were made to replace the aging Nakahama Sewage Treatment Plant with a facility that would provide both advanced treatment and reduce the environmental impact. However, updating this plant posed several technical challenges unique to a large city. The land area was small, a large amount of sewage had to be treated, and the plant had to be energy efficient so that it could be used for decades to come. This is where the smart MBR sewage treatment system SCRUM^* developed by Kubota came into play.

At the time, Kubota's MBR already had the second largest share of the global market, and many had been installed in Japan as well. In addition to past MBR operation data, Kubota and Osaka City jointly verified the treatment performance of MBR for a year, demonstrating its high treatment capacity and reducing power consumption. It was a sustainable technology that enabled the advanced treatment of large volumes of sewage in a smaller area with lower running costs. Kubota's technology will help enrich Osaka's waterfront spaces and future.