Desalination technologies help mitigate global water shortage
An estimated 1 % of the world‘s population currently relies on desalination for its water supply. Over the last 5 years, total capacity of installed desalination has increased 57 %. This trend is expected to continue, with global desalination capacity expected to grow from 76 million m3/day this year to 126 million m3/day by 2016, representing a projected increase in desalination investments from USD 8.3 billion to USD 16.6 billion per year by 2016.
Demand for desalination is expected to continue to grow, particularly in coastal regions with limited freshwater supplies and where desalination is the only viable solution to meet increasing demand for drinking water. For instance, in Singapore – an island with 30 times the population density of the UK – the supply of potable water has struggled to keep up with demand. Desalination and recycled water currently account for 30 % of the country’s needs, and are projected to reach 50 %.
In the past, distillation was the primary method used to desalinate seawater. But within the last 10 years, reverse osmosis (RO) filters have become the technology of choice. RO requires 8 times less energy than multi-stage flash distillation. Still, its energy intensity means that global electricity production would have to increase 10–20 % to supply all households with RO water, making it a viable option only where no other alternatives exist.
More recently, media reports have been touting forward osmosis (FO) as the ultimate solution to the world’s unfolding water crisis. By artificially increasing the salinity of the treated water with a salt substitute that can easily be removed, forward osmosis relies on natural osmotic pressure, making it less energy intensive than RO. Although an elegant concept, the need to treat and recycle additional chemicals increases production costs, partially neutralizing its benefits. Forward osmosis still faces significant challenges linked to its full scale commercialization and its use will remain limited to niche industrial applications for the foreseeable future.
In the meantime, as the more established of the two technologies, and as technological advances continue to reduce its energy intensity, reverse osmosis will remain the most attractive desalination solution. Companies such as Pentair, Xylem, Flowserve, Hyflux, as well as Veolia and Suez-Degrémont, which are experts at providing solutions based on RO technology, are likely to continue to benefit from growth opportunities in the desalination market.
“As an established desalination technology, reverse osmosis and companies active in providing RO solutions are expected to benefit from the growing market for desalination.”