Singapore — PUB, Singapore’s national water agency, appointed CH2M to provide professional engineering services for detailed design and construction supervision of the Tuas Water Reclamation Plant (WRP), a key component of PUB’s Deep Tunnel Sewerage System Phase 2 project (DTSS2).

Tuas WRP, to be located in the west of Singapore, will have the capacity to treat an average dry weather flow of 650 Mega-litres/day (MLD) of domestic and 150 MLD of non-domestic used water collected in distinct deep tunnels and conveyed by gravity to the mega treatment facility.

Tuas WRP will employ advanced treatment processes to minimize specific energy consumption and sludge production and at the same time maximize biogas production for the generation of electricity. Domestic and non-domestic used water will be segregated and treated in dedicated treatment trains. Bio-solids treatment will include anaerobic digestion and thermal hydrolysis.

Tuas WRP will convert used water into NEWater and Industrial Water for reuse predominantly by industry — a key element of PUB’s holistic approach to managing the water cycle.

Tuas WRP is expected to be complete in 2025.

The Deep Tunnel Sewerage System (DTSS) is a cost-efficient and sustainable solution conceived by PUB to meet Singapore’s long-term needs for used water collection, treatment, reclamation and disposal.  When completed, DTSS will include 120 km of link sewers and over 100 km of deep tunnels to convey used water by gravity to major water reclamation plants located at coastal areas. The completed DTSS will also streamline the used water network with three centralized collection and treatment points: Changi WRP (CWRP) in the east, Kranji WRP in the north and Tuas WRP in the west of Singapore.

CH2M worked with PUB to conceptualize the DTSS in the mid-1990s and served as program manager for DTSS1, covering the eastern part of Singapore. DTSS1 was completed in 2008 and included the major CWRP.

DTSS2 will collect and treat used water from the western and southern parts of Singapore.  Tuas WRP will be the largest and most complex infrastructure project to be implemented under DTSS2.

A first in Singapore, Tuas WRP will be co-located with the Integrated Waste Management Facility (IWMF) to be developed by the National Environment Agency (NEA).  Co-location will allow PUB and NEA to harness the potential synergies of integrating used water and solid waste treatment while optimizing land use. Together Tuas WRP and IWMF will maximize the water-energy-waste nexus. A good example of synergy is the co-digestion of food waste with used water sludge at Tuas to increase the yield of biogas, which will be utilized at IWMF to improve steam quality and give rise to higher overall plant thermal efficiency.  This will increase electricity production and enable IWMF to export more to the grid while allowing both facilities to be energy self-sufficient.

CH2M has been working in Singapore for 20 years and has extensive experience in delivering successful water projects for PUB. For Tuas WRP, CH2M and PUB will work closely with Program Manager Black & Veatch + AECOM Joint Venture, who will retain oversight of the overall DTSS2 program.

“CH2M is very excited to be able to continue our 20-year partnership with PUB on what will no doubt be an iconic facility that will become a cornerstone in Singapore’s sustainable water supply strategy and serve the Singapore people for many decades,” said CH2M’s State & Local Governments President Greg McIntyre. “By co-locating the Tuas WRP with the IWMF, the project will continue PUB’s history of innovation and industry leadership.  We also look forward to leveraging our shared values on health and safety to “raise the bar” throughout the entire delivery of Tuas WRP and into operations.”