Have a glass of (sea)water
Prototype of a solar desalination unit is developed following 10 years of research
“Water, water everywhere, nor any drop to drink” goes The Rime of the Ancient Mariner and, by 2025, it could turn out that this centuries-old poem was prophetic.
It is estimated that in less than 15 years, two-thirds of the world’s population will face scarcity of drinking water due to fluctuations of fossil fuel oil supply.
And Malta, although surrounded by seawater, won’t be spared... unless, that is, we reconsider our water production methods.
This is what the University of Malta has been researching for nearly a decade: the desalination of seawater by solar energy.
“If fuel runs low, wind and solar are the only technologies that can ensure uninterrupted water supply to the Maltese islands because we don’t need to depend on others to get them,” said project coordinator Stephen Abela at the University’s Department of Metallurgy and Materials Engineering.
Desalination by reverse osmosis can stave off water shortages for as long as the country has access to oil.
“The supply of energy fuels is not unlimited. In future, there may come a time when even the big countries won’t be guaranteed oil. Smaller countries like us will be even more vulnerable,” said Dr Abela.
Malta consumes roughly about 30 million cubic metres of potable water every year. The Water Services Corporation supplies all of it by pumping up groundwater and by desalinating seawater through reverse osmosis.
“Reverse osmosis is a very energy-intensive process,” explained Dr Abela.
To desalinate and pump water to the network, the WSC uses about 4.5 per cent of the total electricity energy consumed across Malta and Gozo in a year.
Solar desalination, on the other hand, uses the sun to desalinate seawater and produce potable water. A solar desalination unit has no moving parts and needs no technical expertise.
“You can install the unit and practically forget it,” said engineer Paul Refalo, a PhD student also working on the project.
Essentially, a basic unit is made up of a tray covered by a glass box: the clear, potable water trickles down from the sides of the glass and is collected in side trenches in the tray.
Despite its simplicity, there are as yet only few large-scale international solar desalination technologies available.
The technology is relatively young. It extends back to the early 1950s when solar stills were studied for remote desert and coastal communities but these soon gave way to more viable fossil-fuelled projects. The trend is being reversed now due to environmentally pressing issues.
Research on this technology in Malta started out in 2005 when a German institution donated a solar desalination unit to the University.
A year later, the University developed a series of prototypes specifically designed to function in the Mediterranean climate.
Once the potential benefits of this technology were confirmed, a local investor, Ecologic Ltd, entered into partnership with the University and the WSC with the aim to research and eventually manufacture solar desalination units in Malta.
Eight years on, the department is ready to deliver its first optimised prototype.
“It is based on the needs of the atmospheric conditions of Malta and the Mediterranean climate,” said Dr Abela.
Nano-textures were developed for the purpose of this innovative unit to make optimum use of solar energy.
These units, which are durable and can resist gales, can “easily be manufactured in Malta”, according to Dr Abela. At the moment, they produce “at least” five litres of water for every one square metre.
The prototype will be targeted at the international market, “especially countries with a dry climate such as those in the Middle East and North Africa. These have an abundant supply of solar energy and lack freshwater resources,” said Mr Refalo.
Until it is produced on a larger scale, solar desalination units can also be utilised in times of crisis: “At least, they ease the strain on logistics in emergencies,” said Dr Abela.
The engineers stress the importance of changing our mentality and start thinking in terms of becoming more efficient and less wasteful by promoting energy conservation. It is, quite possibly, the only way to ensure we won’t be in hot water in the coming years.
• The research is funded by the Malta Council for Science and Technology.
The University’s Research Innovation and Development Trust has been set up to strengthen investment in high-calibre research and development across every faculty and to attract the necessary funds.
For more information visit www.ridt.org.mt.