Reverse osmosis could provide a backup water supply, but cost would be high
More than 20 years after it was abandoned, desalination could return as a backup to the city's water supply, but in a very different form.
New desalting technology has been proved 'absolutely feasible' in tests over the past year, although the cost would be 44 to 55 per cent higher than using water piped from the mainland, officials say.
They said it was too early to say whether two trial plants at Ap Lei Chau and Tuen Mun would be the forerunners of a much bigger drive to make saltwater fit to drink.
And even if plants were built, they would only be used to supplement the supply from the Dongjiang, the Guangdong waterway that meets 70 to 80 per cent of the city's needs.
'The test results indicated that water desalination is absolutely feasible in Hong Kong and there are no technical difficulties,' Water Supplies Department senior engineer Charles Chan Shu-key said. 'The water has also reached international quality standards and can be safely consumed.'
The two plants tested three methods of reverse osmosis, technology already used in the US, Japan, the Middle East and Spain. It uses membranes that allow water particles to pass through when pressure is applied, separating concentrated salt water and pure water.