From the mid-1950s, Japan's rapid economic growth led to increasing industrialization and urbanization, and society and individual's lifestyles underwent major changes. At that time, however, the country’s sewerage systems could not keep up with the concentration of the population in cities, and water pollution in rivers and seas became even more pronounced. In the 1970s, as water pollution became a major problem and steps needed to be taken to deal with the situation, legal systems were put in place to protect people's health and preserve the living environment. Regulations on wastewater were further tightened, requiring the evolution of treatment technologies.

Kubota has contributed to the construction of sewerage systems that aim to make effective use of water resources with its submerged membranes, a type of advanced wastewater treatment technology that creates new water. These submerged membranes, which were developed in 1986, form a compact membrane filtration system that combines microbial purification and solid-liquid separation using membranes, a revolutionary system that enabled efficient wastewater treatment and easy maintenance. This technology has been applied to sewage treatment plants, wastewater treatment plants (Johkasou), and wastewater reuse systems*1 in urban buildings. We will contribute to the realization of a sustainable society through advanced wastewater treatment for the creation of healthy water environments, the effective use of recycled water, and the use of sewage sludge as energy for resource recycling.