By Lynda Myer
Including the construction of a 98km-long network of deep tunnels and link sewers, as well as the future Tuas Water Reclamation Plant, tunneling works for the second phase of the Deep Tunnel Sewerage System (DTSS), was completed by PUB, Singapore’s National Water Agency.
In order to serving the western half of Singapore, involving the downtown area and new developments such as Tengah Town and Jurong Lake District, this scheme extends the DTSS network.
Being commenced in 2019, tunneling works on Phase 2 incorporated new features to ensure the integrity of the deep tunnels and ease of maintenance, whereas these include the use of concrete resistant to microbiological-influenced corrosion, isolation gates to allow for flow diversion, fibre optic cables for remote monitoring of a tunnel’s structural integrity, and the use of air jumpers to control air flow within the tunnels.
The aim of designing the DTSS in the 1990s was to transform the country’s used water management system, while it is a 206km-long network of tunnels and link sewers planned to meet Singapore’s long-term needs for used water collection, treatment, reclamation, and discharge. It will enable PUB to reclaim and recycle water in an endless cycle.
Considering that the gravity-fed system feeds water to three centralized reclamation plans at Changi, Kranji and Tuas, it is due to allow PUB to decrease the overall land footprint of the used water system across Singapore by half, freeing up to 150ha for higher-value land use.
According to PUB chief executive Goh Si Hou: “As one of the most water-stressed countries in the world, the ability to effectively collect and recycle our used water in a closed water loop has been a game-changer in our quest for water security. The Deep Tunnel Sewerage System is not only an engineering feat, but a key pillar in strengthening Singapore’s water resilience to meet the long-term challenges of climate change and growing water needs.”
