Japanese professor who pioneered advanced wastewater treatment wins LKY Water Prize

Professor Kazuo Yamamoto was awarded the 2020 Lee Kuan Yew Water Prize. ST PHOTO: ALPHONSUS CHERN
The submerged membrane bioreactor technology pioneered by Emeritus Professor Kazuo Yamamoto in use at the Changi Water Reclamation Plant. ST PHOTO: ALPHONSUS CHERN

SINGAPORE - A Japanese professor who pioneered an advanced water treatment technology in the 1980s - which eventually helped to raise the efficiency of making Newater in Singapore - was named the 2020 recipient of the Lee Kuan Yew Water Prize on Thursday (March 17).

Emeritus Professor Kazuo Yamamoto from the University of Tokyo conceptualised the submerged membrane bioreactor technology, which combines advanced filtration processes with a biological wastewater treatment process.

This makes the process more efficient, and reduces the amount of land needed for water treatment.

The membranes are submerged inside wastewater or sewage water.

In the 80s, Prof Yamamoto's idea was met with ridicule and scepticism because immersing membranes inside sludge-ridden used water went against existing scientific thinking and engineering concepts.

Back then, membrane systems were placed outside a tank filled with wastewater. 

But since Prof Yamamoto's lab was small, he had no choice but to submerge the membrane system inside his wastewater tank in a 1984 experiment. 

On the first try, the membranes were clogged with sludge, but he noticed that the treated water that the lab system produced was very clear.

“So I was convinced by (this solution), and I resolved to make it work,” said Prof Yamamoto, who is now 67. 

He built a viable submerged membrane bioreactor prototype in 1988, and it turned out to be the solution to advance wastewater treatment to further public health and water security globally.

Within 15 years of Prof Yamamoto's invention, almost half of all sizeable sewage treatment plants in the world had gone on to use submerged membrane bioreactors in one form or another, said national water agency PUB's chief executive Ng Joo Hee, who unveiled the 2020 Lee Kuan Yew Water Prize laureate on Thursday.

Prof Yamamoto is the first Asian individual recipient of the prize since it was first conferred in 2008.

After he created his prototype in 1988, he chose to give up the intellectual rights to his invention and keep the knowledge in the public domain. He did this because he felt compelled to help solve environmental problems in Japan. 

“I was born in Tokyo, and at that time, water pollution and pollution were very serious in Japan,” he recalled. 

His decision not to patent his invention allowed other wastewater treatment players and researchers to build on his pioneering work and accelerate the adoption of submerged membrane bioreactor technology.

Since 2006, Singapore has adopted the membrane bioreactor technology in used water treatment, and the technology is currently being implemented in three out of four water reclamation plants - in Changi, Ulu Pandan and Jurong.

Currently, about 13 per cent of the used water that the reclamation plants receive undergoes the membrane bioreactor process.

Prof Yamamoto chose to give up the intellectual rights to the technology, keeping the knowledge in the public domain. ST PHOTO: ALPHONSUS CHERN

This will increase to 54 per cent when the Tuas Water Reclamation Plant - the world's largest membrane bioreactor facility - starts operating in 2026.

The membrane bioreactor process produced better-quality treated water in fewer steps than conventional methods, fast-tracking the process of turning treated used water into Newater – Singapore’s high-grade reclaimed water.

The high-quality treated water will also have low impact on the environment when it is discharged into the sea, said Mr Ng. 

He added that before the advent of the membrane bioreactor, wastewater treatment needed significant infrastructural investments in the form of large retention tanks and sedimentation tanks.

The advanced technology can also reduce the amount of space needed for water treatment by up to 50 per cent.

"Tuas Water Reclamation Plant (will occupy) only half the usual footprint because of Yamamoto's discovery. The high quality of effluent that will come out of Tuas... will enhance Newater production and further advance the circularity of Singapore's water economy," said Mr Ng.

The membrane bioreactor process allows used water to be treated in fewer steps compared with conventional methods. ST PHOTO: ALPHONSUS CHERN

PUB chief engineering and technology officer Pang Chee Meng said that the water agency estimates a US$460 million (S$650 million) reduction in some construction and infrastructure costs for the Tuas plant. 

Since 2008, the Lee Kuan Yew Water Prize has honoured outstanding contributions by individuals or organisations towards solving the world's water challenges by developing or applying innovative technologies, policies or programmes.

Prof Yamamoto was selected as the laureate in 2020, but due to the Covid-19 pandemic, his win was announced this year.

The prize is sponsored by Temasek Foundation, and Prof Yamamoto will receive a $300,000 cash prize, a certificate and a gold medallion.

He will receive the medallion from President Halimah Yacob on April 18, during the 2022 Singapore International Water Week.

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