WHO Guidance for Health and Environmental Aspects of Desalination, including Chemical Challenges and Nutrient Minerals

The World Health Organization, through its Eastern Mediterranean Regional Office (EMRO) has developed guidance on health and environmental aspects of desalinated water production, distribution and water quality. The purpose was to generate a level of consistency in the approach to developing desalination projects, so as to facilitate the introduction of desalination benefits, and avoid unnecessary ad hoc judgments. In addition to salts, desalination applications must deal with raw water contamination by oil, inorganic and synthetic organic chemicals, microbial contaminants, scale management, membrane leakage, and chemical and biofouling. Stabilization of the finished water to avoid corrosion is a key element. Environmental impacts are possible with any large construction project and desalination projects may also involve coastal zone issues, energy consumption and efficiencies from cogeneration, and disposal of concentrates at sea or on land. Quality of finished water must be maintained during transit to consumers sometimes over long distances and warm temperatures. These goals should consider positive public health consequences, as well as preventing adverse effects. Several inorganic ions i.e., bromide, borates and bromate, are of particular interest because the first two are not completely removed by membranes, and the third can be present in finished water in large quantities depending upon the treatment processes being employed. Desalinated water can be considered to be “synthesized” water and, as such, its final composition can be tailored to any specific purpose within technological and financial constraints. Components such as TDS, calcium and magnesium mineralization, fluoride and possibly others can be chosen to reflect possible benefits to the consuming population, as well as to assure corrosion stability. This new Guidance will also be a component of the 4th edition of the WHO Guidelines for Drinking-water Quality scheduled for 2009. It is expected to have worldwide impact, due to the already extensive and rapidly growing use of desalination. It should contribute to the improvement of the public health and quality of life and to economic growth. The final Guidance will be published in English and Arabic with a translation provided by the Kuwait Foundation for the Advancement of Sciences. The draft is available at http://www.who.int/water_sanitation_health/gdwqrevision/desalination/en/index.html