SINGAPORE - When Professor Ng Wun Jern ventured into environmental engineering 37 years ago, his realm of expertise did not even have a suitable name.

Back then, it was called sanitary engineering, which most people took as the manufacture of urinals and toilet bowls.

"The mental picture people had was not very flattering," said the 63-year-old.

Prof Ng became a pioneer in what has evolved into a prestigious profession - where engineers help minimise and manage waste and pollution, protecting the air, water, soil, as well as people, from harmful chemicals.

On Monday (Nov 13), Prof Ng was presented with the President's Technology Award by President Halimah Yacob at the Istana, for his work in a field that is now called environmental engineering. Other researchers were also honoured at the President's Science and Technology Awards ceremony for their achievements.

Finance Minister Heng Swee Keat, who spoke at the ceremony, noted that each of the award winners "has achieved some kind of first: whether they are the first to have a particular insight; first to apply their insight in an impactful way; or first to bring others to work together in a new way".

For Prof Ng, who is from the school of civil and environmental engineering at Nanyang Technological University, his work did not take him that far from toilet bowls.

He developed a new type of waste management system for waste water, which includes sewage and chemical waste, one which halved the space taken up by tanks.

A traditional system has tanks filled with micro-organisms to break down sewage, where waste water is continuously churned and mixed to introduce oxygen needed for bacteria activity. The waste water is then transferred to separate tanks, where suspended particles are allowed to settle to the bottom so that the water, with fewer particles, can be discharged.

But Prof Ng discovered that turning off the churning process at certain points in the day to allow for the particles to settle, and then discharging the water directly from that same tank, would be just as efficient. He also found that this saves space too.

He explained that the micro-organisms start to expect "famines" when the water mixing process stops, so they work faster when they encounter waste water.

"So even though the process is stopped at certain times, we can still treat the some amount of waste," Prof Ng said.

His waste management system, which has gone through three generations of changes, is now being used in Singapore, as well as in China, Malaysia, Sri Lanka and Taiwan.

When he tried to introduce his system to industry players, changing their attitudes towards it was initially an uphill task, he admitted.

"I was told it was a 'new class' of waste management, which was just a polite way of saying I had no track record and to shoo me away," said Prof Ng.

But he persevered and eventually got his big break.

Indeed, perseverance is necessary in research, said Professor David Lane, 65, who on Monday received the President's Science and Technology Medal, Singapore's highest honour for research scientists and engineers.

The chief scientist of the Agency for Science, Technology and Research said: "Continuous investment and pursuit are very important to science, often, you just have to keep going even when it is not that clear.

"It might seem dark ahead of you and you have to push quite hard to get to the light."

Prof Lane was awarded for his role in developing Singapore's biomedical sciences sector and his contributions to cancer research.

The medal also went to Professor Edward Warren Holmes, 76, of the National University of Singapore's Yong Loo Lin School of Medicine, for his contributions to translational and clinical research in the health and biomedical sciences here.