Osaka, Japan

The prototype of Osaka's sewerage system can be traced back to the time of Toyotomi Hideyoshi, who built the Osaka Castle before the Edo period.

In the city development, the roads were laid out in a checkerboard pattern and canals and other facilities were constructed, allowing for a logistics system that included water transportation. Based on this, Osaka prospered as a commercial hub and was referred to as the "nation's kitchen".

Osaka City was also called the "city of water", and even today, about 10% of the city is occupied by water.

So, if the river or sea is contaminated, it will not only affect our living environment, it will also bring down the value of the city itself. With water having been integral to the development of Osaka City, it is especially important to maintain and improve the water environment. In that context, the role sewerage systems play is vital.

When the economy was experiencing a period of rapid growth, the water quality of the rivers deteriorated, in inverse proportion to the development of the city.
However, swift actions were taken to rectify this. In 1982, activated sludge treatment started at all 12 existing STPs. In 1984, the sewerage service ratio in relation to the total population reached 99%, meaning that the sewerage system was almost complete.

The sewerage system has greatly improved the water quality of the river, allowing people to walk along the riverside and boats for sightseeing to drift by.
However, we are now facing the problem of aging facilities as the development of the sewerage system started quite a while ago. So, we have been working on their reconstruction and renewal, mainly for mechanical and electrical equipment.

Osaka is mostly made up of urban districts.
Because of that, land is scarce and available spaces have been small since the olden days. Our predecessors in those days have made a lot of efforts to make the best out of the small spaces we have.
The MBR we've adopted can make the best use of existing "boxes" (facilities). With no space to build new structures here, the challenge was how to utilize the existing "boxes" and how to increase their capacity. As we thought about how to improve and how to make it more efficient, one of the best options was Membrane Bioreactor (MBR) technology.

Until now, people have only wanted convenience. But in order to create a sustainable urban environment, it will be important to build infrastructure in a way that will reduce the burden on the environment.That’s why there is more demand than ever before for a big shift in values.

It’s going to be increasingly important that things be energy-saving, resource-saving, and low-carbon, with the functionality to recirculate materials, at low cost.

In terms of water processing, we can’t think of it as just water, because these days it’s becoming important to circulate the materials and energy that are in the water, while also replenishing the water.

And since MBR has the ability to regulate water quality in a number of ways, it’s going to be an increasingly important component in the circulation not only of water, but of everything related to water.

These days there is a big shift toward thinking that water infrastructure shouldn’t just clean the water, it should also reduce all kinds of negative effects on the environment.

MBR has both commercial and public infrastructure uses, and when you combine them it brings about a very interesting metabolism, creating a system that can do things that could never be done before.

I anticipate that introducing new technology like MBR will contribute to building a sustainable society through water.

I think Osaka has great potential to become a role model for major cities all over the world.