Nearly quarter of Phase 2 used water ‘superhighway’ complete, on track for completion in 2025

SINGAPORE: The second phase of Singapore's used water "superhighway" is almost a quarter complete, with about 24km of the 100km-long water conveyance system done as of this month. 

National water agency PUB said on Monday (Apr 19) that work on Phase 2 of the Deep Tunnel Sewerage System (DTSS), which began in 2017, is on track to be completed by 2025. 

First conceived more than two decades ago as part of efforts to enhance Singapore's water resilience, the system uses deep tunnel sewers to convey used water by gravity to centralised water reclamation plants, located at Singapore's coastal areas. 

This used water is then treated and purified into NEWater -  an "ultra-clean, high grade" reclaimed water. 

In 2019, DTSS Phase 2 director Yong Wei Hin said the system will support 55 per cent of Singapore’s water needs this way. 

While the 108km-long first phase of the DTSS - completed in 2008 at a cost of S$3.4 billion - serves the eastern part of Singapore, Phase 2 of the project will cross 100km of the western part of the island, covering the downtown area as well as upcoming developments such as Tengah and the Jurong Lake District. 

Comprising 40km of deep tunnels and 60km of link sewers, Phase 2 of the DTSS - costing about S$6.5 billion - will also support the growth of industrial developments in the west, PUB said. 

READ: PUB to begin tunnelling as part of Phase 2 in building 'used water superhighway'

"Once DTSS Phase 2 is in place, the existing conventional water reclamation plants at Ulu Pandan and Jurong, as well as intermediate pumping stations, will be progressively phased out to free up land for higher value development," said the agency.

It noted the land freed up is equivalent to about 214 football fields -  about 150ha. 

Speaking during a visit to a DTSS worksite along Penjuru Lane, Minister for Sustainability and the Environment Grace Fu said allowing used water to be captured and reclaimed makes Singapore more water resilient as its water can be "reused over and over again".

The completed DTSS will collect and transport water from the whole of Singapore to three water reclamation plants in Changi, Kranji and Tuas for treatment. 

The new Tuas water reclamation plant is part of the upcoming Tuas Nexus, which will also include the National Environment Agency's integrated waste management facility. 

The facility aims to "harness potential synergies of the water-energy-waste nexus by integrating used water and solid waste treatment processes", said the PUB. 

Construction of the Tuas Nexus, which began in 2019, will be completed in phases from 2023.

READ: URA draft master plan: Going underground to free up space on the surface

BORROWING FOR SINGAPORE'S INFRASTRUCTURE

Earlier this month, the S$10 billion DTSS had been identified as one of the infrastructure projects eligible for the proposed Significant Infrastructure Government Loan Act (SINGA).

If passed, the Act will allow the Singapore Government to borrow up to S$90 billion for "nationally significant" infrastructure. 

While the country had borrowed money in preceding decades to pay for projects such as Changi Airport and the first MRT lines, by the 1990s the Government was able to use rising revenues to pay for such infrastructure. 

"But what is happening now is that our needs have grown, the infrastructure is much more complex today than it was before," said Second Minister for Finance Indranee Rajah, who visited the DTSS  worksite together with Ms Fu.  

"There are financial pressures and constraints.  We have an ageing population. So we have to think about how we're going to finance nationally significant infrastructure," she added. 

If passed, SINGA will require that the infrastructure - which should have an expected cost of at least S$4 billion - should be available for use for at least 50 years, and should support Singapore's national productivity or its economic, environmental or social sustainability.

Noting the system is expected to last at least 100 years, the DTSS is a "good illustration" of infrastructure that will benefit from SINGA, said Ms Indranee, noting the project will benefit several generations.