Author: Jeremy Rehm / Source: Science News
Technology meant to help solve the world’s growing water shortage is producing a salty environmental dilemma.
Desalination facilities, which extract drinkable water from the ocean, discharge around 142 billion liters of extremely salty water called brine back into the environment every day, a study finds. That waste product of the desalination process can kill marine life and detrimentally alter the planet’s oceans, researchers report January 14 in Science of the Total Environment.
“On the one hand, we are trying to provide populations — particularly in dry areas — with the needed amount of good quality water. But at the same time, we are also adding an environmental concern to the process,” says study coauthor Manzoor Qadir, an environmental scientist at the United Nations University Institute for Water, Environment and Health in Hamilton, Canada.
Between human population growth and climate change, water is becoming increasingly scarce (SN: 8/18/18, p. 14). Desalination technology has become a viable solution to this problem and has grown exponentially in popularity since the 1980s. Almost 16,000 plants now operate worldwide.
Desalination relies on evaporation or specialized membranes to either chemically or electrically separate pure water from a stream of saltwater. But two streams always flow out of the system: one that becomes water that people can use, and another with the leftover, extra-salty brine, which is released back into the environment.
Previous evaluations didn’t assess how much brine these facilities produced, Qadir says. Scientists assumed that desalination facilities on average equally produced brine and pure water — one liter of brine for every liter of pure water. That turned out to be…
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