SINGAPORE - Water security in Singapore has been boosted with the opening of the country's fourth desalination plant.

The Keppel Marina East Desalination Plant is the only one in the Republic capable of treating both sea and reservoir water, and is part of efforts to ensure that taps never go dry, rain or shine.

The facility, which has been operational since last June, was officially opened on Thursday (Feb 4) by Prime Minister Lee Hsien Loong.

National water agency PUB chief executive Ng Joo Hee said at the event that desalination - or the conversion of sea water into drinkable water - is one of Singapore's four national taps.

"Unlike the other three taps - imported water, rainfall and recycled water - (the sea) is a practically limitless resource," he said.

The plant can treat about 30 million gallons a day (mgd), or up to 7 per cent of Singapore's daily water needs of about 430mgd.

Currently, the lion's share of water in Singapore is imported from Malaysia's Johor River. However, changing weather patterns due to climate change could make water sources replenished by rainfall less resilient.

To ensure water security, Singapore is looking to desalination as a weather-proof source of water. It is also seeking to maximise the use of the resource by recycling every drop to form Newater. With water consumption set to double by 2060, PUB had earlier said that the plan is for Newater and desalination to meet up to 85 per cent of Singapore's future water demand.

On Thursday, Mr Ng said: "The availability of desalination makes Singapore's water supply immensely resilient. And the (new plant) coming online further strengthens Singapore's water security."

The 2.8 ha facility - about twice the size of a football field - can draw water from the sea during periods of dry weather, or treat water from the Marina Reservoir during periods with heavy rain.

It is the first large-scale desalination plant with both these features, and was built following years of testing and research, including a 2007 test of dual-mode desalination at a 1 mgd pilot plant in Pasir Ris.

Multi-use plant

Mr Chew Chee Keong, PUB's director for water supply (plants), told The Straits Times that the facility, located right by the coast and next to the Marina Reservoir, is in a good position to harness both sources of water.

He added: "With climate change, we can expect more weather uncertainty - we are likely to experience more intense rainfall and more severe drought. (The plant's) dual mode function affords PUB greater operational flexibility to respond to the vagaries of weather, thereby strengthening Singapore's water supply resilience."

Mr Tan Boon Leng, managing director for environmental infrastructure at Keppel Infrastructure, the plant's builder and operator, explained that before it was built, Marina Barrage had to pump out excess water into the sea during periods of heavy rainfall, which was "a waste of the rainwater that we captured".

He added: "The key feature here is really to make better use of the investments that we have."

Dr Cecilia Tortajada, an adjunct senior research fellow at the Lee Kuan Yew School of Public Policy's Institute of Water Policy, told The Straits Times that other than boosting water security for the country, the new plant can also help Singapore use its resources more efficiently.

"Energy use is related to how saline water is. During the times freshwater is used, the plant will use much less energy," said Dr Tortajada, who added that the dual function also makes the plant an efficient use of land.

While on reservoir mode, the plant uses about a third of the energy required for it to operate while on seawater mode, according to PUB's Mr Chew.

Dr Tortajada added that despite the financial cost of desalination, it is imperative for Singapore to build up such capabilities to deal with the changing climatic and geopolitical situation.

"Costs of desalination are never uni-dimensional. They are not economic only, but also social and environmental... To see the issue of cost within a broader perspective, one has to also consider what would be the social costs for Singapore of not being able to provide clean water," she said.

Besides being the first dual-mode desalination plant in Singapore, the Keppel Marina East facility is also the first to feature a recreational space, accessible to the public via the Eastern Coastal Loop of the Park Connector Network that bridges East Coast Park and Gardens by the Bay East.

The upcoming Founders' Memorial MRT Station, slated to open in 2025, will be about 1km away on foot.

Pointing to its open green rooftop space spanning about 20,000 sq m, Tanjong Rhu resident Tom Stephens said the plant's design is reminiscent of the Marina Barrage.

The 40-year-old, who works in banking, added that he often takes walks around the plant with his nine-month-old toddler.

"It's beautiful in the evenings, especially with the view of the city skyline," he said.

The plant is the second developed and operated by Keppel under the PUB's Design, Build, Own and Operate arrangement, and will be operated by its subsidiary Marina East Water for 25 years from 2020 to 2045. Its first, the Keppel Seghers Ulu Pandan Newater Plant, commenced operations in 2007.

In winning a 2016 open tender, it was agreed that Keppel would supply water at a first-year price of $1.07867 per cubic m to the PUB.

Other desalination plants

Meanwhile, PUB said that the fifth desalination plant, on Jurong Island, which was slated to open in 2020, has been delayed due to the Covid-19 pandemic, although it is expected to be up and running by the first half of this year.

As for the Tuas South Desalination plant - which PUB took over from embattled water treatment firm Hyflux in May 2019 - it is capable of producing drinking water even while repairs to address operational issues are ongoing, said Minister for Sustainability and the Environment Grace Fu said in a written reply to Mr Gerald Giam, an MP for Aljunied GRC, on Monday (Feb 1).

She said: "The repairs, which included the replacement of ultra-filtration and reverse osmosis membranes, cost around $80 million in total and are on track for completion in mid-2021."