• Cyprus is confronting a severe and worsening water crisis.

• Lying at the far east of the Mediterranean, Cyprus has always lived with drought. But climate change has turned dry spells into a permanent challenge and authorities are increasingly turning to desalination to meet rising water needs.

• Annual rainfall has dropped an estimated 15 per cent in the past 90 years.

• As of September 1, the island's reservoirs were just 14.7 per cent full.

• Demand for water has surged three-fold since 1990 because of population growth and a surge in tourism, leaving Cyprus with a constant water deficit. 

• The country has a population of just under 1 million, and nearly 3 million tourists visit annually.

• In 2023, the deficit reached 66 million cubic metres.

• Desalination was first introduced in Cyprus in 1997 and now covers about 70 per cent of drinking water needs. 

• Mobile plants from the United Arab Emirates were installed this summer, with authorities planning more next year. 

• Ultimately, the government wants desalination to meet all household and business needs.

What is desalination?

• The scarcity of freshwater resources and the need for additional water supplies is already critical in many arid regions of the world and will be increasingly important in the future. Many arid areas simply do not have freshwater resources in the form of surface water such as rivers and lakes. • They may have only limited underground water resources, some that are becoming more brackish as extraction of water from the aquifers continues.

• The process of converting saline water into drinking quality water is called desalination.

• Solar desalination evaporation is used by nature to produce rain, which is the main source of freshwater on Earth.

• The main hurdle that must be overcome to turn seawater into freshwater is to remove the dissolved salt in seawater. That may seem as easy as just boiling some seawater in a pan, capturing the steam and condensing it back into water (distillation). 

• Desalination has been used for thousands of years. Greek sailors boiled water so that fresh water could evaporate away from the salt. Also, the Romans trapped salt with clay filters.

• Other methods are also available, but these technological processes must be done on a large scale to be useful to large populations. However, the current processes are expensive, energy-intensive, and involve large-scale facilities.

• Another way saline water is desalinised is by reverse osmosis procedure. In simplistic terms, water, containing dissolved salt molecules, is forced through a semi-permeable membrane (essentially a filter), in which the larger salt molecules do not get through the membrane holes but the smaller water molecules do. 

• Reverse osmosis is an effective means to desalinate saline water, but it is more expensive than other methods.

• Today, desalination plants are used to convert seawater to drinking water on ships and in many arid regions of the world, and to treat water in other areas that is fouled by natural and unnatural contaminants.

• There are about 15,000 desalination plants around the world. The most notable and biggest plants are in the United Arab Emirates, Saudi Arabia and Israel. Saudi Arabia has some of the largest desalination facilities in the world.

(The author is a trainer for Civil Services aspirants.)