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The Deep Tunnel Sewerage System (DTSS) is a massive underground superhighway for Singapore’s used water management. It is a cost-efficient and sustainable solution designed to meet Singapore’s long-term needs for used water collection, treatment, reclamation and discharge.
The DTSS comprises a 206km-long network of deep tunnels that convey used water entirely via gravity to three centralised water reclamation plants located in Changi, Kranji and Tuas. The treated used water is then reclaimed and further purified into NEWater, with excess effluent discharged to the sea in an environmentally responsible manner.
Costing around $10 billion and designed to last for 100 years, the DTSS is an example of long-term water infrastructure planning and investment to benefit multiple generations. Due to its scale and complexity, the construction of DTSS had to be carried out in two phases.
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Completed in 2008, Phase 1 of the DTSS comprises a 48 km-long deep sewer tunnel running from Kranji to Changi, 60km of link sewers, and a centralised water reclamation plant at Changi.
The Changi Water Reclamation Plant (CWRP) is the cornerstone of the first phase of the DTSS. Sited on 32 hectares of reclaimed land, CWRP features a compact and covered used water treatment facility designed to treat 800,000m3 of used water per day. It can be expanded to handle an ultimate 2,400,000m3 per day of used water.
Phase 2 of the DTSS involves the construction of a 98km-long network of deep tunnels and link sewers, as well as the future Tuas Water Reclamation Plant. These new infrastructure components extend the DTSS network to serve the western half of Singapore, including the downtown area and upcoming developments such as Tengah Town and Jurong Lake District.
The Tunnelling works for DTSS Phase 2 were successfully completed in August 2023. However, additional construction activities remain on-going, including the casting of the internal Corrosion Protection Lining (CPL), pipe jacking works for the link sewers, and site reinstatment works. Furthermore, mechanical and electrical works are still to be completed at specific locations. The entire DTSS2 network, including the Tuas Water Reclamation Plant, is scheduled to be commissioned in 2026.
The DTSS allows for efficient, large-scale water recycling, as every drop of used water is collected, treated and purified in an endless cycle. This boosts our capacity to produce NEWater, Singapore’s third National Tap and a weather-resilient source of water.
The DTSS allows for efficient, large-scale water recycling, as every drop of used water is collected, treated and purified in an endless cycle. This boosts our capacity to produce NEWater, Singapore’s third National Tap and a weather-resilient source of water.
