Singapore’s national water agency, the Public Utilities Board (PUB), has appointed three contractors to design and build the first 30 kilometres of deep tunnels and link sewers for the Deep Tunnel Sewerage System (DTSS). The contractors are Ed Zublin AG (Singapore Branch), Penta-oCean Construction Co., Ltd. and Koh brothers Building & Civil Engineering Contractor (Pte.) Ltd. Joint Venture, and Leighton Contractors (Asia) Limited (Singapore Branch).
The deep tunnels and link sewers are part of a 40-kilometre network of deep tunnels and 60 kilometres of link sewers for DTSS Phase 2, and will be built with the tunnelling method. Subsequent contracts to build the remaining deep tunnels and link sewers will be awarded from 2018.
The contractors were appointed following a pre-qualification and tender exercise in mid-2016, with the three contracts valued at a total of S$1.51 billion (US$1.12 billion). Over the coming seven years, they will develop the detailed design and construct some 30 kilometres of deep tunnels and link sewers as well as the associated ancillary structures.
The complete network, consisting of 100 kilometres of deep tunnels and link sewers, will connect to the Tuas Water Reclamation Plant, which is expected to be completed in 2025. By then, Singapore will be wholly served by the DTSS, and used water will be conveyed from the DTSS via gravity to three centralised water reclamation plants for treatment before it undergoes further purification to produce NEWater, or discharged into the sea.
“The deep tunnels are an integral part of the DTSS, conveying every drop of used water for treatment and channelling it for further reclamation into NEWater,” Mr Yong Wei Hin, Director, DTSS Phase 2, PUB, said. “As the backbone of NEWater production, the DTSS ensures the sustainability and resilience of the used water network to facilitate large-scale water recycling in Singapore, and contributes to the goal of increasing the overall water recycling rate from 40 per cent to up to 55 per cent of total water demand in the long term. We are happy to partner these three experienced contractors and Lead Consultant Black & Veatch + AECOM Joint Venture to construct this major component of DTSS Phase 2.”