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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: 2) by Runaway1956 on Wednesday January 16 2019, @03:43PM (21 children)
Seriously, why can't the brine be oxygenated?
(Score: 5, Informative) by ElizabethGreene on Wednesday January 16 2019, @04:06PM (16 children)
As the concentration of salt increases the ability to dissolve oxygen decreases. i.e. there is only so much "room" in solution. Adding more of a highly soluble substance (Salt) can cause lower solubility substances to come out of solution.
In chemistry this is known as "Salting Out".
(Score: 3, Interesting) by Runaway1956 on Wednesday January 16 2019, @04:15PM (1 child)
And, the reverse doesn't apply then? You can't aerate the water to remove some portion of the salt.
(Score: 2) by fido_dogstoyevsky on Wednesday January 16 2019, @10:30PM
Difficult because the salt is more soluble than oxygen. Much simpler to just evaporate the water and then think about what to do with the solid salt instead.
It's NOT a conspiracy... it's a plot.
(Score: 0) by Anonymous Coward on Wednesday January 16 2019, @04:15PM (13 children)
I have a Democratic solution... Add fresh water to the brine.
(Score: 2, Insightful) by Anonymous Coward on Wednesday January 16 2019, @04:22PM
Not so simple - you have to raise taxes first!
(Score: 2) by Alfred on Wednesday January 16 2019, @05:25PM (10 children)
(Score: 0) by Anonymous Coward on Wednesday January 16 2019, @06:16PM (7 children)
It will never dilute to "pretty much the same as seawater". Eventually the worlds oceans will be a (dead) Salton Sea. It's a chemistry lesson.
(Score: 4, Informative) by slinches on Wednesday January 16 2019, @08:37PM
Do you know how much water is in the oceans? It's effectively infinite. To desalinate all of it to the point that you increased the average salt content by 1% you'd have ~1.5 billion liters of fresh water for each person on the planet.
(Score: 3, Touché) by PartTimeZombie on Wednesday January 16 2019, @08:53PM (4 children)
You should Google "Water Cycle" or "Hydrologic Cycle"
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @12:16AM (3 children)
You should take a chemistry class. The water cycle isn't going to remove salt/brine that's already laying stuck on the lower levels of the oceans. The level will gradually rise as more shit is added. It may take a long long time, but it'll happen.
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @02:52AM (1 child)
Example... The Salton Sea was once a freshwater lake. Now it's toxic.
(Score: 2) by Alfred on Friday January 18 2019, @04:05PM
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @02:55AM
I suspect what is being said here is that water extracted from the ocean will return to the ocean.
Perhaps after being blended,brewed,filted by kidneys,bleached,chlorinated.
(Score: 2) by realDonaldTrump on Thursday January 17 2019, @08:48AM
Dumb California Dems made so many crazy crazy environmental laws which aren't allowing the massive amount of readily available water to be properly utilized. It is being diverted into the Pacific Ocean. While they pump other parts of ocean dry for their drinking water. And horrific Fire spreads through the Forests. Must Water forest, Rake & Tree Clear!!!
(Score: 2) by linkdude64 on Wednesday January 16 2019, @08:59PM (1 child)
Idea:
Build a brine-desalination plant!
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @03:27AM
They can just use the water from the desal plant!
Seriously though, this could work. Most cities process water. Mix the brine in before it goes back into the ocean. It may even help clean the treated waste water further.
(Score: 2) by Gaaark on Wednesday January 16 2019, @09:16PM
I have a delicious solution: add French fries and malt vinegar.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2) by Immerman on Wednesday January 16 2019, @05:01PM (3 children)
Where would the oxygen come from? Doesn't matter if it's oxygenated originally, things living in it will breathe that away fast enough.
The problem is that you create underwater brine rivers and lakes that don't mix well with the surrounding seawater, and so they don't receive the oxygen being carried down from the surface water where it's introduced by photovores and atmospheric mixing.
(Score: 2) by Runaway1956 on Wednesday January 16 2019, @06:59PM (2 children)
I was thinking along the lines of aerating the brine like you aerate an aquarium - mechanically pumping air into the brine. But, apparently, that won't work worth squat because it won't cause any salts to settle out of solution. So, about the only other thing I can think of has already been mentioned - dry the brine, and haul the salts off where they can be used, or stored.
I was just thinking out loud here, I got nothing more to offer.
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @03:04AM (1 child)
Near the desal plant find and area with high enough hills, build a dam 3/4 the way around it with concrete, and build a gate system on the 4th side with concrete filling the gaps withsand. The sand will act as a filter. On the sand filter side, do this again. 3 dams in a row. Have a wall in the first dam so half is in use at any given time.
Build a pipe from the desal plant to the first dam. Fill one side. Wait for the water to filter through the sand to the 2nd then 3rd dam.
When the salt buildup in the first dam is enough to mine, start using the other side of the first dam leaving the first side to dry.
When the first side is dry use earth moving equipment to remove the salt.
By the time the water exits the 3rd dam it is still salty but far cleaner. It could probably be piped back into the desal plant.
Wash. Rinse. Repeat.
(Score: 0) by Anonymous Coward on Thursday January 17 2019, @03:08AM
A solution to this problem was floated whereby the brine would be piped or trucked into a desert to be power sprayed into sand dunes.
The theory being that the desert environment would quickly evaporate the brine with the water escaping into the air, and hence back into the oceans eventually, or would seep through the desert into the canals under the desert. Either way the water returns with the salt left behind.