Vision, boldness and tenacity – these are some of the qualities that saw Singapore through its journey to achieving security and sustainability in water.

Based on the oral history account of Mr Tan Gee Paw, Mr Tan’s interview in Challenge magazine (September 2011) and PUB’s 2009 annual report.

Mr Tan Gee Paw made water his career, and never left. One of the pioneering engineers who helped shape our water story, Mr Tan joined the Public Works Department in 1967 as a civil engineer. Though he’d hoped to build bridges and high-rise buildings, he was posted to the Drainage Department

But this proved to be a blessing in disguise. Through his work, he came to know every river, stream and drain in Singapore. “When I met colleagues, we didn’t say, ‘Meet at this junction and road’. We’d say, ‘Meet at the junction of this river and that road’,” says Mr Tan.

From the start, Mr Tan and his fellow officers sought to find fresh solutions to old challenges. In the 1960s, to determine the reliable yield figure for a reservoir, officers had to manually compute the rainfall inflow into the reservoir and the demand outflow from the reservoir for each day throughout the 60 years of rainfall records available. This was tedious, repetitive work and would take more than a year to complete. Mr Tan tinkered with the Fortran programming language and worked out the figure in five minutes. “That was the power of computers,” he says. This experience would later guide his enthusiasm for using technology to solve our water woes.

Bigger countries often have larger resources of water, so they seldom thirst. This wasn’t the case for Singapore. A plan was needed, and the seeds of our water supply strategy – known as the Four National Taps and comprising local catchment water, imported water, NEWater and desalinated water – were sown in the 1972 Water Master Plan.

The first challenge was addressed in the 1970s when creating
urbanised water catchments became a priority. The other twoquestions lingered, and Mr Tan and his team focused on various methods to collect and recycle used water. “We started experimenting with recycled water in 1974, building a pilot plant to treat used water into potable-quality water,” says Mr Tan. “While the idea was good, the technology wasn’t – the membranes were expensive and weren’t reliable.” The plant was therefore decommissioned, although PUB continued to keep abreast of technological developments in the field.

The turning point came when membrane technology matured and became more affordable in the late 1990s. The NEWater system wasn’t an overnight solution but a combination of technologies – including microfiltration, reverse osmosis and ultraviolet disinfection – that had been tested and refined over decades. The groundbreaking, three-stage process is meant to be more than comprehensive. “When I looked at the water [for the first time], I was amazed,” Mr Tan recalls. “It was clearer than the water in swimming pools. Though we’re forward-looking when it comes to technology, we must remain conservative when it comes to water quality.”

The first NEWater plants opened in Bedok and Kranji in 2003. Then Prime Minister Goh Chok Tong did the honours at Bedok. “He turned on a symbolic tap, and at that moment, we opened the valves that released NEWater back into our reservoirs for the very first time in history,” says Mr Tan. “It was a historic moment. We’d finally closed the water loop.”
Still, this left a final question unanswered: how would PUB ensure every drop of used water is collected to produce NEWater?

The solution came in the form of the Deep Tunnel Sewerage System (DTSS), a water superhighway that runs deep underground via two major tunnels and which collects used water from every part of Singapore. This is channelled to two centralised water reclamation plants, one in the east at Changi, and the other in the west at Tuas. The first phase of DTSS, which includes a tunnel in the eastern half of Singapore and the construction of the Changi Water Reclamation Plant, was completed in 2009. The second phase is scheduled for completion in 2024.

It’s an ambitious project decades in the making. “I don’t think my career will span long enough to see its full implementation,” says Mr Tan. “Short-term planning will never work in areas like water. You’ve got to plan 50, 100 years ahead.”

Recalling his youth as a civil engineer and how he found his calling, he adds, “I reached a crossroad early in my career in the Civil Service: should I stay or find my fortune in the private sector, where many of my peers had successfully ventured into? I found the answer, not in myself, but in people and water.”