Substantial uncertainties remain about the environmental impacts of desalination, the report says. Limited studies suggest that desalination may be less environmentally harmful than many other ways to supplement water — such as diverting freshwater from sensitive ecosystems — but definitive conclusions cannot be made without further research.
Researchers should investigate the extent to which fish and other creatures get trapped in saltwater intake systems in various settings, and seek ways to mitigate this and other impacts. Studies also should examine the long-term ecological effects of disposing of the salt concentrate that remains after desalination in rivers or the sea, a common practice. In addition, environmental evaluations of new desalination plants should be conducted, including ecological monitoring before and after the plant starts operating. The results should be synthesized with existing data in a national assessment that can guide future decision making, the report says.
Desalination also has raised concerns about greenhouse gases because it uses large amounts of energy. Seawater reverse osmosis uses about 10 times more energy than traditional treatment of surface water, for example, and in most cases uses more energy than other ways of augmenting water supplies. Researchers should investigate ways to integrate alternative energy sources — such as the sun, wind, or tides — in order to lower emissions from desalination, the report says.
[Via Eurekalert]