Desal Membranes Said Best for Removing Contaminants

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

According to Tom Pankratz, a director of the International Desalination Association, 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. 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 Commonwealth Scientific and Industrial Research Organization study conducted by the University of New South Wales titled "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 percent of both PPCPs and EDCs present in the water and were the only technology that consistently yielded these results.

"The water industry is well aware of the increasing number of anthropogenic pollutants—everything from caffeine and aspirin to steroids and antibiotics— that are making their way into the public water supply," said Pankratz. "Concern about the potential adverse impact of EDC/PPCPs and their metabolites in the environment has been an issue for at least 10 years, and the long-term effects of continuous, low-level exposure are still not well understood. However, the discovery and quantification of many of these emerging compounds has been delayed due to limitations in analytical techniques, and the fact that there are little or no regulatory or policy guidelines that govern them," he added.

The International Desalination Association is a non-profit association of over 2,000 members in 58 countries. The membership is comprised of scientists, end-users, engineers, consultants and researchers from governments, corporations and academia. IDA is associated with the United Nations as part of a growing international network of nongovernmental organizations.

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