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posted by chromas on Wednesday January 16 2019, @02:28PM   Printer-friendly
from the where's-my-solar-freakin'-cirruswaterfontuseer? dept.

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?


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  • (Score: 3, Interesting) by insanumingenium on Wednesday January 16 2019, @05:09PM (6 children)

    by insanumingenium (4824) on Wednesday January 16 2019, @05:09PM (#787446) Journal

    TFA started with

    every liter of freshwater a plant produces, 0.4 gallons (1.5 liters) of brine

    So we knew they were sloppy from the getgo, pick one, real units, or freedom units. Don't put the end product in real units, but the byproduct in freedom units because readers are more likely to understand it intuitively and only want them to have a intuition of one half.

    TFA also kept implying that desalination was adding other contaminants

    a salty, chemical-laden byproduct

    later in TFA they call out copper and chlorine in particular, both of which are in seawater already. Now perhaps I am not up to date, but the methods of desalination I am aware of (distillation and filtration) don't involve adding anything to the water. Am I missing a step where they throw "toxic" (their word not mine) chemicals into what will be drinking water (presumably just for fun)? Or are they just trying to imply a straight up scaremongering fiction?

    Would it not be scary enough to say that desalination increases the relative concentration of all solutes in the byproduct? Seriously it would have been better if they added something like "increases the concentration of existing sulfates and fluorides compared to incoming seawater", which would also be scaremongering bullshit, but at least it wouldn't be implying a comic book villain twirling his mustache while pouring vats of "evil chemicals" into the brine.

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  • (Score: 2, Insightful) by nitehawk214 on Wednesday January 16 2019, @05:25PM (3 children)

    by nitehawk214 (1304) on Wednesday January 16 2019, @05:25PM (#787460)

    I think the issue is that those materials become a problem when they are concentrated. Dumping that concentrated brine back into the ocean would cause environmental issues.

    Maybe they can just sit it out in collections pools, to dry as they do for salt mining? I suppose the plants produce way too much for this to be feasible.

    --
    "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
    • (Score: 3, Funny) by isostatic on Wednesday January 16 2019, @05:31PM

      by isostatic (365) on Wednesday January 16 2019, @05:31PM (#787464) Journal

      Dump it into the dead sea and it will dilute the dead sea.

    • (Score: 2) by insanumingenium on Wednesday January 16 2019, @05:36PM

      by insanumingenium (4824) on Wednesday January 16 2019, @05:36PM (#787466) Journal

      Did you perhaps miss the parent comment talking about diluting the brine with seawater? Any way you cut it, implying that the brine is inherently toxic just plain isn't accurate. Yeah, this could be an engineering problem, but it isn't pouring toxic waste into the waterways like they are trying to imply.

      Though I am seriously wondering how long it will take someone to come up with some sort of a "use a giant egg beater it mix the outflow with the source water" solution. That will be a fun one. Hell it might even be more efficient than pumping dilution water around. Hell there is probably a solution possible based on using a static structure that when you pump water through it will cause turbulent mixing.

    • (Score: 2) by ElizabethGreene on Thursday January 17 2019, @04:01PM

      by ElizabethGreene (6748) Subscriber Badge on Thursday January 17 2019, @04:01PM (#787905) Journal

      > I think the issue is that those materials become a problem when they are concentrated.

      This is accurate. The core problem is that the difference in saline concentration is enough to encourage the two solutions to stratify. That means the concentrated seawater remains concentrated instead of mixing with unconcentrated seawater. This stratification is how you get brine lakes and deoxygenated zones that damage benthic organisms. If you dilute the wastewater you can greatly reduce this effect.

  • (Score: 3, Informative) by DeathMonkey on Wednesday January 16 2019, @07:15PM

    by DeathMonkey (1380) on Wednesday January 16 2019, @07:15PM (#787504) Journal

    later in TFA they call out copper and chlorine in particular, both of which are in seawater already. Now perhaps I am not up to date, but the methods of desalination I am aware of (distillation and filtration) don't involve adding anything to the water. Am I missing a step where they throw "toxic" (their word not mine) chemicals into what will be drinking water (presumably just for fun)? Or are they just trying to imply a straight up scaremongering fiction?

    It's a little bit of both. Copper, for example, is present in seawater but it doesn't really cause any problems. At higher concentrations, though, it starts killing fish eggs (aka exhibits toxicity). "Pollution" is defined by it's consequences.

    And, they do use descaling agents and other chemicals in the process itself. Additionally, water coming into contact with parts containing heavy metals will can leach those metals.

    And, finally, the high salt concentration itself is toxic.

  • (Score: 1, Troll) by realDonaldTrump on Thursday January 17 2019, @08:10PM

    by realDonaldTrump (6614) on Thursday January 17 2019, @08:10PM (#788013) Homepage Journal

    Gas Passing Animal Assad used Chlorine on his own people!!