x Abu Dhabi, UAEFriday 21 July 2017

Building boom for desalination plants

Some 700 new plants were commissioned around the world in the last year, with a further 244 plants under contract or in construction.

DUBAI // The world's water desalination capacity is increasing at a record rate, and nations must take care to minimise the environmental impacts, a report released yesterday in Dubai said. The document, compiled by Global Water Intelligence, an industry publication, also said that Saudi Arabia and the UAE were, respectively, the world's first and second biggest producers of desalinated seawater. The two countries also jointly have 10 of the largest desalination plants operating or under construction.

"As capacity grows, environmental impacts grow with them," said Tom Pankratz, a director with the International Desalination Organisation (IDA) and editor of the Water Desalination Report. Desalination removes the salts in seawater, leaving potable water. "The impact that is most obvious to most people is the concentrated discharge which is generally twice saltier than seawater," said Mr Pankratz.

The report, released in conjunction with the IDA, also counted 14,451 plants online with a total capacity of 59.9 million cubic metres per day, according to Christopher Gasson, the publisher of Global Water Intelligence. Some 700 new plants were commissioned around the world in the last year, with a further 244 plants under contract or in construction. That equates to a growth in the last 10 months of 12.4 per cent, according to the report.

The industry has been affected by the global economic crisis, but despite an anticipated dip in growth next year, the number of desalination plants is expected to grow. Beyond the byproducts of desalination, the technology's high power requirements present a serious issue, experts said. The industry has been eager to show that technological advancements and improvements in plant design and management can reduce these impacts.

Moving intakes further offshore was one way to reduce damage to the marine environment, Mr Pankratz said. Another option was sub-seabed intake, in which there is both intake and pre-treatment of the seawater with sand acting as a filter. Habitat restoration was yet another option, Mr Pankratz said. Technology exists to dissipate the plant outflow more quickly using diffusers and to target outflow so that wave action helps spread out the saline brine.

In Australia, for example, desalination is coupled with wind power, which means no additional fossil fuels are burnt to produce potable water. Officials from two of Australia's desalination plants in Sydney and Perth demonstrated how their projects are addressing some of the environmental challenges facing the industry. The Perth plant uses reverse osmosis, which is more energy-efficient than the thermal processes used in the Gulf; employs energy-recovery equipment and does environmental monitoring.

The measures require additional investment; the environmental monitoring alone adds US$3 million (Dh11m) a year to the cost of the project. Mr Pankratz said that many of the latest measures had not yet been implemented in Gulf states. "These are relatively new," he said. Many desalination plants in the Gulf are older, said Dr Corrado Sommariva, an IDA director and technical programme co-chairman. "You have plants operating now that were designed 20 or 30 years ago when environmental concerns were not that strong," he said. "A big emphasis should be to retrofit."

The IDA World Congress on Desalination and Water Reuse runs until Thursday at Atlantis, The Palm in Dubai. vtodorova@thenational.ae