ENVIRONMENT & WATER ENGINEERING
PUB AWARDS TUAS WRP
BIOSOLIDS TREATMENT CONTRACT This facility will form the key interface between the Tuas Water Reclamation Plant and the Integrated Waste Management Facility. National water agency, PUB, has awarded the contract to build the biosolids treatment facility for the Tuas Water Reclamation Plant (Tuas WRP) - a major component of the Deep Tunnel Sewerage System (DTSS) Phase 2 project - as the construction of the plant gathers steam this year. Sembcorp Design and Construction Pte Ltd, a wholly-owned subsidiary of local construction and property group, Chip Eng Seng Corporation Ltd, will construct Tuas WRP’s biosolids building, digesters and greasy waste receiving facility. Works have been scheduled to start in April 2020 and are due to be completed in 2025. The contract is valued at SGD 433 million and was awarded following an open tender exercise in August 2019, during which a total of 11 bids were received. These facilities will form the key interface between Tuas WRP and the National Environment Agency’s (NEA) Integrated Waste Management Facility (IWMF). Collectively, Tuas WRP and IWMF are known as Tuas Nexus, Singapore's first initiative that integrates water and solid waste treatment processes to harness synergies of the water-energy-waste nexus. At Tuas WRP’s biosolids treatment facility, used water sludge will be co-digested with IWMF’s food waste to increase the yield of biogas which will then be combusted at the IWMF to boost power generation and improve its
overall plant energy efficiency. “This is a key contract that will build components critical to realising the synergies between Tuas WRP and IWMF, with PUB and NEA working together closely to make Tuas Nexus a reality. Once completed, Tuas Nexus will set the bar for addressing long-term resource sustainability and climate change”, said Mr Yong Wei Hin, Director, DTSS 2, PUB. PUB’s DTSS Phase 2 project consists of a 100 km network of deep tunnels and link sewers. Slated for completion in 2025, it will channel used water via gravity from the western half of Singapore to Tuas WRP for treatment. Existing conventional WRPs in Ulu Pandan and Jurong will be progressively phased out. With an initial treatment of capacity of 800,000 m³ per day, Tuas WRP will house the largest membrane bioreactor facility in the world, with an overall 30% more compact footprint compared to conventional plants. In July 2019, PUB appointed a joint venture to construct Tuas WRP’s Influent Pumping Stations which are responsible for pumping used water from the underground sewerage tunnels to the plant for treatment. Another 14 construction tenders for Tuas WRP will be called over the next two years, including for the construction of the plant’s domestic and industrial liquids modules.
An artist's impression of Tuas Nexus, which shows the co-location of the Tuas Water Reclamation Plant (Tuas WRP) and the Integrated Waste Management Facility (IWMF). Image: PUB, Singapore’s National Water Agency and National Environment Agency (NEA). THE SINGAPORE ENGINEER April 2020
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