The Dirty Truth about Turning Seawater into Drinking Water:
As countries in the Middle East, Africa, and elsewhere struggle to find enough freshwater to meet demand, they're increasingly turned to the ocean. Desalination plants, located in 177 countries, can help turn seawater into freshwater. Unfortunately, these plants also produce a lot of waste—more waste, in fact, than water for people to drink.
A paper published Monday by United Nations University's Institute for Water, Environment, and Health in the journal Science of the Total Environment found that desalination plants globally produce enough brine—a salty, chemical-laden byproduct—in a year to cover all of Florida in nearly a foot of it. That's a lot of brine.
In fact, the study concluded that for every liter of freshwater a plant produces, 0.4 gallons (1.5 liters) of brine are produced on average. For all the 15,906 plants around the world, that means 37.5 billion gallons (142 billion liters) of this salty-ass junk every day. Brine production in just four Middle Eastern countries—Saudi Arabia, Kuwait, Qatar, and the United Arab Emirates—accounts for more than half of this.
[...] "Brine underflows deplete dissolved oxygen in the receiving waters," said lead author Edward Jones, who worked at the institute and is now at Wageningen University in the Netherlands, in a press release. "High salinity and reduced dissolved oxygen levels can have profound impacts on benthic organisms, which can translate into ecological effects observable throughout the food chain."
Whatever happened to the idea of towing icebergs to where water was needed?
(Score: 5, Interesting) by JoeMerchant on Wednesday January 16 2019, @02:47PM (1 child)
I thought that "duh" was the appropriate response. When you desalinate seawater, of course you're going to make fresh water and saltier water. If you store the brine in a lake you'll eventually make a "Sea Salt" factory (complete with microplastic particles...) If you concentrate the brine and eject it slowly into the sea, it will sink like the brine lakes found (just recently) at the bottom of the Gulf of Mexico, and doubtless many other places yet to be discovered. Very few creatures are "brine adapted," though a few are.
I think the real problem is when a highly populous country (like Saudi Arabia) desalinates a massive amount of seawater in a relatively small body of water (like the Red Sea and/or Persian Gulf). In the larger oceans the brine could be effectively diluted, say mixed 1:50 with normal seawater, before discharge.
🌻🌻 [google.com]
(Score: 3, Interesting) by lentilla on Thursday January 17 2019, @12:38AM
Don't you just love the unscientific bait in the lede?
So here is my brilliant plan: "only" produce one litre of fresh water for every fifty litres of seawater. That means you end up with 49 litres of brine (oooh... scary!) Pump that 49 litres of slightly salter water back into the ocean. Considering that sea water has an average salinity of 3.5% [wikipedia.org], your outflowing brine now has a salinity of 3.57%.