Desalination Plants Produce More Brine Than Fresh Water

Tik Root reports on a new study in the journal Science of the Total Environment about the outputs of desalination plants:

The literature had long assumed a one-to-one ratio. But [Manzoor] Qadir’s study found that the average desalination plant actually produced 1.5 times more brine than desalinated water—fifty percent more than previously thought. That translates to 51.8 billion cubic meters of brine each year, which Qadir says is enough to cover all of Florida, a foot deep.

Root notes that 16,000 plants are currently in operation or under construction around the world. The facilities are costly to operate, require large amounts of energy, and produce significant emissions. But the brine especially concerns scientists because of the effects of the salinity and temperature of the water and because copper and chlorine used during desalination ends up in the discharge. 

Some observers believe that the brine is not a huge problem because it can be disposed of safely, but others say the problem runs deeper. "[John] Burt adds that while regulation can help mitigate these risks, enforcement varies widely from place to place. And, in the Arabian Gulf, where nearly half of the world’s desalination occurs, he says oversight tends to be relatively weak," writes Root.