The next stage of development of Singapore's first integrated water and solid waste treatment facility, in Tuas, has begun.
The facility will help maximise energy and resource recovery and optimise land use.
This phase involves the development of a 400-tonnes-a-day food waste treatment facility and an 800-tonnes-a-day sludge incineration facility, the National Environment Agency (NEA) said yesterday.
With this, the first phase of development of Tuas Nexus Integrated Waste Management Facility is expected to be completed by 2025.
These facilities will play a key role in realising Singapore's vision of zero waste and a circular economy.
The contract for the next stage was awarded to a joint venture between UES Holdings and China Harbour (Singapore) Engineering Company for $428 million.
The proposals were evaluated based on their process design and optimisation, resource efficiency, Green Mark initiatives, plant layout and value for cost.
Tuas Nexus consists of two mega facilities managed separately by national water agency PUB and the NEA. Set to be completed in phases from 2025, it will locate PUB's Tuas Water Reclamation Plant next to the NEA's Integrated Waste Management Facility.
It will be energy self-sufficient through the harnessing of synergies from the two facilities. This is expected to result in savings of more than 200,000 tonnes of carbon dioxide annually, equivalent to taking 42,500 cars off Singapore's roads.
When completed, the food waste treatment facility will provide Singapore's primary means of treating source-segregated food waste.
Inorganic materials are first separated from food waste. The food waste is then turned into a slurry, which will be co-digested with used-water sludge to produce biogas and improve energy recovery.
Burning the biogas will generate electricity to run Tuas Nexus, with enough left over to be exported to the national grid to power up to 300,000 four-room Housing Board flats.
The sludge will then be incinerated at the facility. This means that sludge from the Tuas Water Reclamation Plant will not have to be transported elsewhere for treatment, thus reducing the carbon footprint.
NEA chief executive Luke Goh said: "This next stage of the Tuas Nexus development focuses on integrating advanced facilities to treat food waste and sludge from PUB's Tuas Water Reclamation Plant. Integration of these typically distinct treatment processes is complex but delivers the benefits of higher energy recovery and lower carbon emissions."