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Techutante t1_j20l0rn wrote

Reply to comment by Surur in UIUC Researchers propose a new way to get fresh water from seawater, without the disadvantages of traditional desalination. They say that a vertical “capture surface” that is 210 m wide and 100 m tall, could extract enough vapor floating above warm oceans to supply 500,000 people with freshwater by lughnasadh

Also we have a HUUUUGE demand for salt as a society, so they can reuse that brine. Mostly for clearing roads at this point during poor weather, which is a whole other can of worms. (salting the earth)

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PubicHair_Salesman t1_j20m1eh wrote

Trouble is that the parts of the earth where desalination is necessary are typically very far from places where brine solution is needed to thaw roads.

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Techutante t1_j20tf61 wrote

Have you been to California?

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teesee150 t1_j21x5gk wrote

Have you been to saudia arabia

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junktrunk909 t1_j21ohy9 wrote

I've read posts about this several times and they conclude that the salt that is generated by this process at scale is far more than there would be a market for and the salt that is generated is more of a sludge.

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Techutante t1_j21qce5 wrote

Yeah, some solutions I've read include filling in old pit mines (many of which were dug out of salt veins because it's easy to get through), brine based storage solutions as a heat battery or ultra-cooling facilities for data centers.

Each solution has it's own problems of course, like salt leeching into ground water tables and a lack of scale to handle the possible output of brine.

Atmospheric condensation is a bit of a troublesome issue in it's own way though right, because you're altering the climate distribution of moisture. Not that we aren't altering everything all the time, but imagine if a country were to divert the flow of water from a river that historically ended in another country.

Only then imagine you're doing it with the rivers in the sky instead. Obviously it would be quite a while before capture technologies scaled up to that point, but it's not out of the realm of possibility.

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sharksfuckyeah t1_j21w7td wrote

A few days ago I read a headline about salt based batteries being more efficient than lithium batteries. Maybe there’s a way to create batteries while also generating both power and clean water at the same time: https://energycapitalpower.com/researchers-develop-sea-salt-battery-4-times-the-capacity-of-lithium/

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Techutante t1_j2215mo wrote

Yeah I think they brinier the better for those too.

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Greenhoused t1_j227488 wrote

They dump salt All over the roads wbere it freezes too

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thatawesomedrunkguy t1_j229w3m wrote

The problem is though, its cheaper for salt consumers to buy mined salt than from desalination plants. To concentrate seawater enough to create a viable salt product from the brine would take 4-5x more energy than simply desalinating for potable water use. That is on top of the 2-3x more capital equipment you'll need for this process. It doesn't make it economically feasible to do so (at this time). There's promising technology that's being researched and piloted, but until there is that gap is filled, then desal plants are going to keep dumping concentrate back from where they got their water.

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Techutante t1_j22k4ty wrote

I think they just pump it in a big tank or open field and let it evaporate. Bulldoze it later.

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thatawesomedrunkguy t1_j22s905 wrote

Most desal plants are producing in the tens of millions of gallons per day range. In order to get a proper evaporation, you're going to need a whole lot of surface area. Just not practical.

Plus, not as simple as concentrating evaporating seawater to get salt. You gotta separate your other type of salts that will form once the brine saturates.

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Techutante t1_j22sq04 wrote

They apparently mine brine for various minerals and trace metals, I was just reading. Rare earth elements and whatnot.

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g0ing_postal t1_j257hyt wrote

The amount of salt produced by desalination plants in staggering

We produced and 290 million metric tons of salt worldwide in 2021: https://www.statista.com/statistics/237162/worldwide-salt-production/

Seawater contains 3.5% salt and has a density of roughly 1020kg/m3, so a cubic meter of seawater has any 35.7kg of salt https://en.m.wikipedia.org/wiki/Seawater

We generate tightly 95 million m3 of water from desalination plants per day globally https://en.m.wikipedia.org/wiki/Desalination_by_country

That's about 3391.5 million kg of salt per day

290 million metric tons= 290,000 million tons

290,000/3391.5 = 85.5 days

If we processed the waste from desalination plants all the way into salt, we would fulfill the world's demand for salt in less than 3 months. That's assuming we don't produce salt from any other sources

We would end up with over 4 times the annual salt production on just the current amount of desalination

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Techutante t1_j266o76 wrote

Yeah, and demand for fresh potable water is only likely to grow.

However thawing meltwaters from glaciers and icepacks may counter out some of that salinity. I'm not quite up on the ocean science for that though at present.

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