Membranes used in desalination

Research indicates that membranes used in desalination operations are the only technology that consistently removes more than 90% of all the 'new' contaminants found in drinking water.

According to Tom Pankratz, a director of the International Desalination Association (IDA) and editor of the weekly Water Desalination Report, membranes that employ nanofiltration or reverse osmosis technologies to remove salt from water also effectively and consistently remove most organic compounds classified as pharmaceuticals and personal care products (PPCPs) and endocrine disruptors (EDCs).

These substances have been found in water supplies and watersheds throughout the world.  A recent investigation by the Associated Press showed that trace amounts of up to 56 different pharmaceutical compounds were found in tap water of 24 US metropolitan areas serving at least 41 million people.  Most traditional water treatment facilities do not routinely remove these contaminants.

PPCPs include prescription and non-prescription medications and veterinary drugs (PhACs), as well as products used for personal health or cosmetic reasons (PCPs), from sunscreens to detergents.  Endocrine disruptors (EDCs) are chemical compounds that can potentially interact with endocrine systems, or glands, that secrete hormones directly into the bloodstream.  EDCs include steroids, pesticides and industrial chemicals. 

"Membranes used in desalination effectively remove compounds that are considered PPCPs and EDCs because they are designed to separate dissolved ionic constituents from solution,” said Pankratz.

A CSIRO study conducted by the University of New South Wales entitled EDCs and PPCPs in Reclaimed Waters in Australia showed how effective membranes are in the removal of PPCPs and EDCs in comparison to more conventional treatment processes. According to this research, membranes using reverse osmosis removed more than 90% of both PPCPs and EDCs present in the water, and were the only technology that consistently yielded these results.

Membrane technologies are used in more than half of the desalination facilities around the world, including most plants operating in the US and Australia.  Desalination, or desalting, processes produce potable water from seawater or brackish water for domestic or municipal use. Desalting equipment is now used in more than 100 countries, reflecting the growth in desalination operations worldwide.