Singapore company work on construction of ambitious Deep Tunnel Sewerage System (DTSS) Phase 2. Construction already began in 2017 with an estimated to cost S$6.5 billion. It is planned to finish in 2025. It has 40 km of deep tunnel sewers and 60 km of link sewer.

Sembcorp work on Kranji part of Deep Tunnel Sewerage System (DTSS) with 12.6 km tunnel from Kranji Sewerage Treatment Plant to approximately 1.3 km east of the Seletar Expressway flyover to Lentor Avenue.

The primary lining consists of concrete segmental lining 250 mm thick with internal diameter 4100mm. Final cast-in-place concrete lining with HDPE corrosion protection membrane will be placed within the concrete segmental lining with a finished internal diameter 3600mm. A TBM of 4.93m diameter started excavation from Mandai Road.

https://www.sembcorpae.com/showcase/infrastruture/36-kranji-deep-tunnel-sewerage-system-dtss