PUB, Singapore’s national water agency, has appointed CH2M Hill Singapore Pte Ltd as the Detailed Design Consultant for the Tuas Water Reclamation Plant (WRP).
The WRP is a key component of the Deep Tunnel Sewerage System (DTSS) Phase 2, PUB said on its press release on 13 February.
CH2M Hill Singapore was appointed following a pre-qualification and tender exercise in 2016. Over the next two years, the firm will develop the detailed design of Tuas WRP and subsequently supervise the construction and commissioning of the plant.
The DTSS uses deep tunnel sewers to convey used water entirely by gravity to centralised WRPs located at the coastal areas. The used water is then treated and further purified into ultra-clean NEWater, with excess treated effluent discharged to the sea.
DTSS Phase 1, comprising the North and Spur Tunnels, the associated link sewers, the Changi WRP and outfall, has been completed in 2008. A NEWater factory, located on the rooftop of the Changi WRP, was built in 2010 to facilitate large-scale water recycling.
Expected to complete by 2025, DTSS Phase 2 will extend the deep tunnel system to cover the western part of Singapore, including the downtown area and major upcoming developments such as Tengah Town.
The construction of Tuas WRP is expected to commence in the second half of 2018 and will feature multiple construction tenders for civil, mechanical and electrical engineering works as well as equipment providers for various plant components, PUB said.
PUB explained that unlike conventional WRPs, the advanced Tuas WRP will be receiving used water flows from the western part of Singapore via two separate deep tunnels:
- A tunnel to convey domestic used water, and
- Another tunnel to convey high-strength industrial used water.
It will also use membrane bio-reactor (MBR) technology 1 to treat both used water sources and to higher standards. Domestic used water will be treated at a 650,000m3/day (or 143 million imperial gallons per day) module and then further purified to NEWater, while industrial used water will be treated at a separate 150,000m3/day (or 33 million imperial gallons per day) module and sent back to industries for re-use.
1 MBR technology is used in the treatment of used water. A bioreactor houses naturally-occuring bacteria which break down waste products in used water, after which microfiltration/ ultrafiltration membranes – with fine pores invisible to the eye – filter the remaining impurities.
“MBR is a more efficient method as it optimises the used water treatment process, enabling used water to be treated using less steps and less space compared to conventional systems, and produces a higher quality treated effluent,” PUB said.
The treated water can then be used to supply industries or as feed water for NEWater production.
With an initial total treatment capacity of 800,000m3/day (176 million imperial gallons per day or 320 Olympic-size pools), Tuas WRP will be the largest MBR facility in the world, but with a 30 percent more compact footprint compared to conventional plants.
Tuas WRP will also feature an integrated NEWater factory, with an initial capacity of 25 million imperial gallons per day. Furthermore, Tuas WRP will be co-located with an incineration facility to harness the potential synergies of the water-energy-waste nexus, making it more efficient and greener.
Mr Yong Wei Hin, PUB Director DTSS Phase 2 said, “DTSS Phase 2 continues to leverage advanced technologies and detailed planning to enhance Singapore’s used water management system and ensure water resilience and sustainability for generations to come. With a separate network for the collection and treatment of industrial used water, the Tuas WRP enables PUB to not only meet the growing water needs of the industrial sector, but also ensures the continued reliability of NEWater. ”
Cornell, Howland, Hayes & Merryfield (CH2M) was found in 1946. CH2M HILL has been working in Singapore for more than a decade and has a partnership with PUB. It was the program manager and designer for the Deep Tunnel Sewerage System, which won the ‘Water Project of the Year’ at the GWI Global Awards 2009; the Changi WRP, one of the world’s largest water reclamation projects; and PUB’s Active, Beautiful, Clean Waters (ABC Waters) program, which launched in April 2006.
CH2M Hill was involved in Phase 1 of DTSS as the detailed design consultant for the Changi WRP. In Phase 2, CH2M Hill Singapore will partner with PUB over the next 10 years to deliver the new Tuas Water Reclamation Plant.
Singapore’s four national taps are water from Malaysia, the local reservoirs, desalination and NEWAter. Last week PUB also has put up a Request for Proposal (RFP) for the development of Singapore’s fifth desalination plant on Jurong Island.