WATER is an important component in our lives. It is a natural resource that covers 75 per cent of Earth’s surface. However, only three per cent is potable.
The most serious problem affecting human beings is the global water crisis.
A growing population and development have increased the demand for quality drinking water. It is projected that by 2030, the global demand for water will increase from 4,500 billion cubic metres to 6,900 cubic metres. As such, the future needs are more than the current surface water resources.
More than 80 countries face serious water issues. Countries that are not facing water shortages may soon find themselves facing problems unless they reduce the demand for water or develop additional sources of water.
To resolve the issue, researchers have conducted studies to develop sustainable technologies to meet increasing water consumption.
Desalination is one of the technologies that produce clean water for drinking, irrigation, industry and development.
Based on its separation mechanism, it can be categorised into thermal and membrane desalination.
The desalination market is increasing not only due to increasing water demand but also due to the reduction in the cost of desalination.
The thermal or distillation process separates salts from water through evaporation and condensation, while membrane desalination separate salts from water based on a filtration process.
The market for desalination is increasing worldwide, not only in regions where water demand is high and limited in supply, such as the Middle East and North Africa but also in countries such as Spain and Australia, where desalination technologies were unthinkable in the past.
Today, the total worldwide desalination capacity is around 66.4 million cubic metres per day.
In the early 1970s, the main issue with desalination production was its high cost. Advanced technology has helped to increase efficiency and reduce cost.
The cost of desalinated water has fallen from US$3.50 in 1979 to US$0.55 in 2000.
The investment cost in desalination production differs between thermal and membrane desalination.
Thermal technology is costly because it requires larger footprints and uses expensive material and equipment. It also uses a large amount of energy compared with membrane technology, which needs only electric energy.
Reverse osmosis, nanofiltration and membrane distillation are some of the popular membrane desalination technologies used in saline water treatment.
Wan Syarizawani Wan Chik, Faculty of Civil Engineering, Universiti Teknologi Mara, Johor