In support of Singapore’s long-term approach towards water resilience, AECOM and its joint venture partner teamed up with PUB, Singapore’s national water agency, to deliver a sustainable solution for used water management.


The Deep Tunnel Sewerage System (DTSS) is a core used water infrastructure which provides a cost-effective and sustainable solution to support Singapore’s continued growth and meet its long-term used water infrastructure needs.


DTSS uses deep tunnels to convey used water by gravity to centralized water reclamation plants (WRPs) located at the coastal areas. The used water is then treated and further purified into ultra-clean, high-grade reclaimed water known as NEWater, with excess treated effluent discharged to the sea through an outfall.


AECOM, together with its joint venture partner Black & Veatch, is the appointed professional engineering services consultant overseeing the development, engineering, and construction of DTSS Phase 2 which covers the Western and Southern parts of Singapore. DTSS Phase 2 comprises the following components:


  • 40 kilometers of deep tunnels running largely under the Ayer Rajah Expressway, that will connect with the existing used water infrastructure to create one seamless and integrated system
  • 60 kilometers of link sewers that create an interconnected network to channel used water from the existing sewerage pipelines to the deep tunnels
  • Tuas WRP
  • Outfall to discharge treated effluent into the sea

Upon completion, the DTSS scheme will result in a reduction in land taken by used-water infrastructure with three centralised collection and treatment points: Changi WRP in the east; Kranji WRP in the north; and Tuas WRP in the west. The existing conventional WRPs at Ulu Pandan and Jurong, as well as intermediate pumping stations, will be progressively phased out and the land freed up for higher value development.


A highlight of DTSS Phase 2 will be the new Tuas WRP which will contribute to Singapore’s long-term goal of increasing the NEWater supply to meet up to 55% of total water demand, further strengthening water sustainability and resilience for Singapore. In addition, the Tuas WRP will treat 800,000 cubic meters of used water per day, making it the largest membrane bioreactor facility in the world.


To maximize the potential synergies of the water-energy-waste nexus, the co-location of Tuas WRP and the Integrated Waste Management Facility (IWMF) marks Singapore’s first initiative to integrate used water and solid waste treatment processes. Nine synergies between the Tuas WRP and IWMF will maximize both energy and resource recovery. One such synergy is the sharing of energy generated from the combined co-digestion of food waste and sewage sludge. The co-location will also be the first facility of its kind in the world that was planned from the ground-up.


  • Feasibility study, preliminary design and programme management