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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: 2) by Immerman on Wednesday January 16 2019, @05:01PM (3 children)

    by Immerman (3985) on Wednesday January 16 2019, @05:01PM (#787440)

    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.

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  • (Score: 2) by Runaway1956 on Wednesday January 16 2019, @06:59PM (2 children)

    by Runaway1956 (2926) Subscriber Badge on Wednesday January 16 2019, @06:59PM (#787498) Journal

    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)

      by Anonymous Coward on Thursday January 17 2019, @03:04AM (#787739)

      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

        by Anonymous Coward on Thursday January 17 2019, @03:08AM (#787742)

        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.