Saturday, March 23, 2013

S'pore's next challenge: 'Treating more seawater with less energy'

Mar 23, 2013
By David Ee

EVEN if Singapore realises its quest to supply all of its own water, it faces another challenge: acquiring the energy it takes to produce the water.

That was the point raised by Minister for the Environment and Water Resources Vivian Balakrishnan at yesterday's book launch of The Singapore Water Story, which chronicles the country's rise to becoming a world leader in water management.

"Singapore has to realise that, in fact, we have translated a dependence on water to a dependence on long as you've got energy, you've got water," said the minister at the National University of Singapore's Bukit Timah campus.

The technologies employed in water treatment here today, for example, reverse osmosis, require substantial amounts of energy.

The Minister explained that as the country becomes more water self-sufficient, this "simply substitutes one strategic vulnerability for another".

To meet its energy challenge, Singapore will have rely on the same things that worked in its water story - political resolve, a clear vision, the right pricing, and a commitment to technology.

Today, Singapore produces at least 40 per cent of its own water needs - with three quarters coming from reclaimed Newater, and the rest from treated seawater.

National water agency PUB wants this to double to 80 per cent by 2060.

Reverse osmosis, the most common method to treat seawater here, typically uses up to 4.5 kilowatt hours to produce 1,000 litres of desalinated water.

That is enough energy to power an HDB flat for several hours.

But PUB is seeking to reduce these levels with new technologies. For example, it is working with Keppel Seghers to develop Memstill technology, which uses waste heat to treat seawater. The process can reduce energy use by up to two-thirds.

It is also exploring longer term solutions such as bio-mimicry, which copies the way some plants and animals treat seawater for their survival, using negligible amounts of energy.

By 2060, Singapore's water usage could double to almost 800 million gallons a day, enough to fill more than 1,200 Olympic-size swimming pools each day.

[Singapore is so humid, we should try to see how we can use Hyflux's "Dragonfly" water extractor to extract water from the air, and run that partially on solar-power. Maybe have solar panels on HDB roofs to run the dragonfly units, that would channel the extracted water to the water tanks.]

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