Sewers are often referred to as “invisible infrastructure.” Buried underground and rarely seen, they play an essential role in treating wastewater from households and businesses before returning it to nature. However, their installation requires large-scale construction, meaning mountainous regions, depopulated districts, and other areas still lack adequate sewer systems today. Furthermore, Japan currently faces various challenges with regards to its sewers, including aging facilities and operational difficulties stemming from population decline and financial constraints.

Onsite wastewater treatment systems are attracting renewed attention as an onsite water treatment system that can solve these issues. We spoke with FujiClean Co., Ltd., a pioneer in onsite wastewater treatment systems manufacturing with one of the top shares of the Japanese market, about the future of water infrastructure.

Transforming water infrastructure through public-private collaboration

Onsite wastewater treatment systems utilize microorganisms to purify household greywater and blackwater, then discharge the treated water. Traditionally, sewer systems that collect wastewater in a single location for treatment have been installed in densely populated urban areas due to their efficiency in terms of construction and maintenance costs. In Japan, however, sewage and community wastewater systems are currently facing increasing challenges from aging infrastructure and reduced economic viability due to population decline. As a result, a transition from sewer systems to onsite wastewater treatment systems that treat both blackwater and greywater is accelerating (in Japanese) in many municipalities.

“Onsite water treatment may be more suitable in some regions, as this allows for treating wastewater at the level of each household or facility, shortening construction time and reducing building costs. For example, if our system is installed, construction time can be shortened by 75% and costs reduced by 49% compared to conventional methods. Onsite wastewater treatment systems were originally developed as a temporary solution to enable the use of flush toilets until sewer systems could be built. With significant advances in water treatment technology, they are now increasingly seen as a new kind of infrastructure that complements sewer systems,” says Takuya Ishida, Deputy General Manager of the General Affairs Department.

Japan’s Ministry of Land, Infrastructure, Transport and Tourism and the Ministry of the Environment are promoting prefectural plans for efficient wastewater treatment facility development (in Japanese), which call for using sewer systems and onsite wastewater treatment systems as appropriate, according to the local conditions. This initiative aims to explore new kinds of infrastructure through public-private collaboration. As part of this effort, FujiClean participated in the Quick Sewage System Project which was implemented in certain areas where more than 10% of the population who do not have access to wastewater treatment facilities (approximately 7.8 million people) (in Japanese). Working with operation teams of other wastewater treatment systems, the company provided new technologies and methods for sewer planning in areas with declining populations.

“Currently, there is a growing movement across Japan to decommission sewage treatment plants and community wastewater facilities, and replace them with individual onsite wastewater treatment systems. As we look toward the future design of water infrastructure, we hope to work in collaboration with local governments and water and sewerage consultants to offer better solutions that consider local populations and regional characteristics,” explains Kosuke Ito, Planning & Sales Section, Sales Department.

A wastewater treatment facility development project in Alabama, the U.S. (from the FujiClean website)

FujiClean also participated in a wastewater treatment facility development project launched by the state public health department of Alabama in the U.S. To explore solutions that meet local needs, the company worked together with the Alabama state government, a local NGO, universities, public institutions, and a manufacturer of water and housing products LIXIL to conduct tests of various methods on 100 households.

“Building social infrastructure requires public-private collaboration involving local governments, residents, and companies that provide technical solutions. Having all stakeholders think together and cooperate from the early stages, the project team can introduce appropriate technologies suited to local conditions and develop high-quality, sustainable infrastructure,” notes Shunya Kitai, Manager of the Overseas Business Department.

The CDC Foundation states that an estimated 2.2 million people in the U.S. lack access to basic sanitation facilities such as toilets and showers. The hope is that this project will serve as a model case for other regions facing the same challenges.

Sustainable infrastructure: The key lies in digital transformation in maintenance processes

Training session for maintenance service engineers (from the FujiClean website)

Facility maintenance is essential to maintain water quality and ensure the continued use of onsite systems as sustainable infrastructure. However, a shortage of skilled personnel in this field is anticipated in the future, making it an urgent issue to address. In addition to sharing expertise and developing human resources both in and outside Japan, FujiClean is working to advance research and development aimed at digital transformation (DX) in maintenance processes.

For large, advanced systems, the company has already put into practical use a remote monitoring system utilizing IoT sensors (in Japanese), which is expected to deliver various benefits such as halving the number of maintenance inspections, and enabling early detection of malfunctions.

“Maintenance DX is key to building and sustaining water infrastructure. The inside of a tank within the system has 100% humidity, presenting a highly challenging environment for electrical systems, but we will continue our development efforts to enable the application of this technology to all our products, including small-scale systems,” says Ito.

Restoring a healthy water cycle

(from the FujiClean website)

FujiClean has set forth the restoration of natural waterways in its mission, and is aiming to purify and recycle water on-site after it has been used by people and polluted.

“In nature, water is cleaned through the biological purification mechanisms of the natural environment. Our business is centered on harnessing the power of microorganisms to clean water to a certain standard with minimal energy consumption before returning it to nature, based on the natural water cycle,” says Ishida.

FujiClean has developed its business not only in Japan but also in the U.S., Europe, and Australia. For example, in New York State, where coastal waters have become increasingly polluted due to population growth, the company participated in a government-led project as one of the few manufacturers offering nitrogen removal technology that meets state standards. In the UK, the company provided onsite wastewater treatment systems equipped with iron electrolysis units as an alternative to conventional systems that raised concerns about impacts on human health and ecosystems, contributing to a solution that addresses water pollution while reducing environmental impact.

In recent years, low- and middle-income countries have also gradually been tightening wastewater treatment standards. FujiClean is participating in a demonstration project conducted by the Japan International Cooperation Agency (JICA) in the Philippines to support the development of sewer infrastructure.

Looking ahead to a future in which everyone can access safe and clean water and sanitation and beyond, FujiClean’s wastewater management systems are playing a part in building infrastructure that supports the restoration of a healthy water cycle.

(Author: Chiaki Iwamura, translation by Rowan White)