The Deep Tunnel Sewerage System (DTSS) is a used water infrastructure project being developed by the Public Utilities Board (PUB) of Singapore to meet the country’s long-term clean water needs.

DTSS deploys deep tunnels to convey used water to 3 centralised water reclamation plants (WRP) located in the coastal areas.

The used water is then treated and further purified into clean water to be supplied under the brand name NEWater, with excess treated effluent discharged to the sea through outfall pipes.

The project involves the construction of two large tunnels, 6.5m in diameter and with a total length of 80km, located about 50m below the surface, to carry sewage to 3 centralised WRPs.

The project is developed in two phases. The first phase was completed in 2008 and comprises a 48km-long underground tunnel system to channel the flow of water from existing gravity sewers to the Changi WRP in the east and Kranji WRP in the north.

The second phase will extend the tunnel system to the west through a 30km-long south tunnel, 60km of link sewers, the Tuas WRP and a 12-km deep-sea outfall.

For the second phase, Dextra supplied 1,210 rock bolts for stabilising the tunnel excavations and 8 GFRP 软眼 for TBM breakthrough.

第二阶段预计于 2022 年完成后，大士水处理厂的 NEWater 工厂将满足新加坡总用水需求 55%。

此外，Tuas WRP 每天将处理 800,000 立方米的废水，使其成为世界上最大的膜生物反应器设施。