x Abu Dhabi, UAETuesday 25 July 2017

University leads the way with do-it-yourself desalination system

Campus in Ajman cuts bills by producing its own water supply using reverse osmosis technology.

Dr Zeinalabedeen Rizk, of Ajman University of Science and Technology, in the campus's desalination plant.
Dr Zeinalabedeen Rizk, of Ajman University of Science and Technology, in the campus's desalination plant.

While industrial-scale desalination serves most of the country's water needs, some organisations have bought their own, much smaller plants to cut their water bills. Ajman University of Science and Technology, for example, has two desalination plants at its main campus, both using reverse osmosis technology. That type is easier to assemble and better suited to small-scale operations, according to Dr Zeinalabedeen Rizk, dean of the university's Institute of Environment, Water and Energy. One of the machines is three years old and can process some 360,000 litres (80,000 gallons) a day, while the other, which is at least 10 years old, can handle up to about half that.

The newer plant, being more efficient, can produce one cubic metre of water for about 25 fils, while the estimated cost for the older plant is about 50 fils, including electricity and maintenance. Both offer a considerable saving on water supplied by the municipality. A cubic metre of desalinated water in the UAE generally costs between Dh3 and Dh4 to produce, although heavily subsidised consumers pay less than this.

"The municipality water is expensive, so we'd rather have our water supply that's guaranteed," said Dr Rizk. "We know what we need and we know what the plant can give us." The savings to the university from desalination and its own sewage treatment plant, which produces water for the grounds, are as much as Dh50,000 per month. Each desalination plant uses water extracted from an aquifer about 20 metres underground and produces water drinkable according to World Health Organisation standards, although it is not used for drinking.

The university kitchens buy purified water while water for student housing is supplied by the municipality. One thorny problem remains - and it is a microcosm of that facing all attempts to exploit groundwater supplies in the UAE. The waste water produced by the process is about twice as saline as that taken out of the ground and this, Dr Rizk acknowledged, was "the main concern" environmentally. In an attempt to minimise the impact, the waste water is injected into a highly saline natural aquifer about 50 metres below the level of the tapped resources and separated from them by a layer of clay.

"It's a hazard," said Dr Rizk. "We don't just let it loose. We inject it down to the saline aquifer so we don't do that much harm." In Dr Rizk's view, desalination technology has been slow to make inroads because the world's most advanced countries do not have to rely on the process. "It's not an urgent need in the US or Europe or Japan because they have enough, maybe an excess, of fresh water," he said.

In the future, he believes, "we'll use the sun to desalinate water. This will be better for the environment." dbardsley@thenational.ae