Safe drinking-water from desalination

Safe and clean drinking-water is an essential element of health security and underpins sustainable socio-economic development. Global climate change, a growing global population, water requirements to support food security and rapid urbanization all contribute to increased water scarcity and compound the challenge of providing safe drinking-water. In many parts of the world there is a need to develop and manage alternative sources of safe drinking-water.

Advances in membrane technology have made desalination of seawater and brackish waters an increasingly viable alternative to produce safe drinking-water. For example, desalination has been gaining foothold in the water-scarce WHO Region of the Eastern Mediterranean, along coastal areas of Australia, on the West Coast of the USA and in many Small Island States including Singapore and Maldives. With this development comes a clear public health argument to provide guidance on ensuring the safety of drinking-water produced with this technology.

Under the auspices of the WHO Drinking-water Quality Expert Group, WHO has developed guidance that focuses on chemicals and microbes of particular concern in the context of desalination. The key chemical and microbial risks associated with major operational aspects of the desalination process, such as source water quality management, treatment, and the blending of final waters, are discussed in the context of WHO Water Safety Plan framework to guide Member States in effectively managing a safe drinking-water supply from desalinated sources.

This WHO guidance document is health-focused and it builds on the publication “Desalination technology: health and environmental impacts” (Cotruvo et al.) which covers the broader context of environmental, technical and operational aspects of desalination.