Desalinated water forms the second weather-resilient pillar of Singapore's Four National Taps strategy. Surrounded by seawater but lacking natural freshwater aquifers, the country has invested heavily in reverse osmosis desalination to convert the strait's brackish and marine water into potable supply. Four desalination plants currently operate across the island, with a combined output of approximately 160 million gallons per day (mgd).
SingSpring Desalination Plant
SingSpring was Singapore's first large-scale desalination facility, opened in 2005 in Tuas. Built and operated by Hyflux under a 20-year DBOO (Design, Build, Own, Operate) concession, the plant initially produced 30 mgd of desalinated water using seawater reverse osmosis (SWRO) technology. The facility draws feedwater from the Strait of Singapore and processes it through pre-treatment, high-pressure RO membranes and post-treatment mineralisation.
Tuas Desalination Plant
Commissioned in 2018 and operated by Tuas Power-led consortium, the Tuas Desalination Plant has a capacity of approximately 300,000 cubic metres per day. It was the first desalination facility in Singapore to incorporate rooftop solar panels, generating a portion of its own energy requirement.
The plant covers 3.5 hectares and at full capacity addresses roughly 30% of Singapore's daily water demand. It received the "Desalination Plant of the Year" award at the 2019 Global Water Awards.
Tuas South Desalination Plant
Tuas South operates alongside the original Tuas facility, adding further seawater processing capacity to the western industrial zone. Together, the two Tuas-area plants form the densest desalination cluster in Singapore.
Keppel Marina East Desalination Plant
The Keppel Marina East plant, commissioned in 2020, is the most technically distinctive of Singapore's desalination facilities. Operated by Marina East Water Pte Ltd under a 25-year concession, it has a rated capacity of 137,000 cubic metres per day (about 30 mgd).
Key features that differentiate this plant:
- Dual-mode operation — the plant can process both seawater and freshwater from the Marina reservoir, switching modes based on supply conditions and demand
- Underground construction — the treatment systems are built below ground level, freeing the 20,000 square metre rooftop for public green space
- Urban integration — located adjacent to Gardens by the Bay, the facility demonstrates that heavy water infrastructure can coexist with residential and recreational zones
The plant won "Desalination Plant of the Year" at the 2021 Global Water Awards, the second consecutive year a Singapore facility earned the recognition.
Energy Consumption and Cost
Desalination remains the most energy-intensive of Singapore's four national taps. Current SWRO technology requires approximately 3.5 to 4.0 kilowatt-hours per cubic metre of water produced. PUB and research partners at NTU and NUS are actively working to reduce this figure through:
- Next-generation membrane materials with higher permeability
- Energy recovery devices that capture pressure from the RO reject stream
- Electrochemical desalination approaches that bypass the need for high-pressure pumps
- Biomimetic membranes incorporating aquaporin-like channels
The target is to bring desalination energy consumption below 2.0 kWh per cubic metre within the next decade, which would significantly reduce the operational carbon footprint of seawater treatment.
Seawater Quality and Pre-Treatment
Feedwater quality in the Strait of Singapore varies with tide, season and nearby shipping activity. Pre-treatment systems at each plant remove suspended particles, organic material and potential membrane foulants before the water reaches the RO stage. Common pre-treatment steps include dissolved air flotation (DAF), dual-media filtration and ultrafiltration membranes.
Post-treatment adds back essential minerals (calcium and magnesium) and adjusts pH to meet potable water specifications before distribution into the public supply network.