this post was submitted on 12 Nov 2023
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135
Desalination system could produce freshwater that is cheaper than tap water (www.freethink.com)
submitted 1 year ago by Salamendacious@lemmy.world to c/news@lemmy.world
21 comments fedilink hide all child comments
 

MIT engineers and collaborators developed a solar-powered device that avoids salt-clogging issues of other designs.

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[–] Wooster@startrek.website 13 points 1 year ago (5 children)

With my (admittedly limited) understanding of the topic, extracting the water from ocean water is a relatively simple process.

The problem is what do you do with the brine afterwards. The process featured in the article makes it harder for the brine to clog the system, which is admittedly an important step. But you can’t put the brine back into the ocean without risking killing local wildlife.

And I’m not under the impression that there are any practical uses for brine, at least not at that scale.

[–] Sanchokan@kbin.social 10 points 1 year ago (1 children)

Would it be posible to salinate the waste water that goes back to the ocean from treatment plants?

[–] interceder270@lemmy.world 9 points 1 year ago (1 children)

I think the problem is that it's too salinated and needs to be put back into the ocean slowly over a wide area.

[–] Dark_Arc@social.packetloss.gg 3 points 1 year ago (1 children)

Well this would be mixing the treated water with the salt ... which in theory should get close-ish to the amount of water put into the system/the original balance

It actually sounds pretty reasonable at least on the surface.

Another idea might be shipping that off for cheap road ice control in states with winter weather

[–] zero_spelled_with_an_ecks@programming.dev 1 points 1 year ago

There's a lot more in the salt than just salt, probably introducing a bunch of issues into trying to use it for deicing roads.

[–] surfrock66@lemmy.world 8 points 1 year ago

I've always wondered why we can't contain the brine and pack it into abandoned salt mines for long-term storage. It would probably inspire some maintenance on abandoned salt mines and prevent cave-ins.

[–] trackindakraken@lemmy.whynotdrs.org 8 points 1 year ago

There are no perfect solutions.

Of course, we'll put the brine back into the ocean. We can run pipelines out miles to disperse the brine and dilute it. We'll need regulation to ensure this, because no capitalist corporation will do anything that cuts into profits without regulations forcing it.

Second only to air, fresh water is what we all need. We'll do what we must to have it. Of this I'm certain.

[–] Kache@lemm.ee 6 points 1 year ago* (last edited 1 year ago)

Maybe have ocean voyaging ships (e.g. container ships) do controlled release of brine through their journey?

Though probably no way of achieving this via current economic and legal systems. Even if attempted today, ships would probably be incentivized to dump the entire payload the moment they cross into internal waters.

[–] Ryan213@lemmy.world 5 points 1 year ago

Clump it into a big ball and send to space!

[–] billwashere@lemmy.world 6 points 1 year ago* (last edited 1 year ago)

Bet Nestle shuts this shit down somehow…

Edit: damn I can’t spell for shit

[–] Kecessa@sh.itjust.works 5 points 1 year ago* (last edited 1 year ago) (1 children)

Big box with pipe pointing up in the middle that exits the box through the bottom to reach a collection tank

Fill with salt water without going past the pipe opening

Add transparent lid with a slope towards the middle so the water condenses and drops in the pipe

Go do whatever you want all day, you've got a passive drinking water creator and nothing to clog since solids just accumulate at the bottom and can be scooped out as needed.

[–] zero_spelled_with_an_ecks@programming.dev 1 points 1 year ago (1 children)

Scooped out and put where?

[–] Kecessa@sh.itjust.works 0 points 1 year ago

Most of it is salt, I know many places where they would gladly buy it for winter road maintenance.

[–] Xavier@lemmy.ca 4 points 1 year ago (2 children)

Small question (perhaps dumb on my part as I haven't slept yet), do these desalination system remove other chemicals such as PFAS, arsenic, lead? I think I read that they use nanofiltration membranes to remove almost everything. How about molecules that are smaller than water (H₂O)? Do they get filtered?

[–] GreyEyedGhost@lemmy.ca 3 points 1 year ago

Most molecules aren't smaller than water, however filters that are small enough to only let water through clog pretty quickly. That said, most heavy metals and salts won't evaporate in a decent still (which is good, because atoms and ions are often smaller than water). I'm not sure about PFAS and microplastics, but I expect they don't evaporate.

[–] primal_buddhist@lemmy.world 3 points 1 year ago

Depends if they also evaporate.

[–] AlteredStateBlob@kbin.social 3 points 1 year ago (1 children)

Yeah, no. It won't be cheaper than tap water. The amount of energy required for desalination, clogging or no, is an additional cost on top of what you need to do to get water drinkable with non salinated water. So no matter the energy source, this cost has to be factored in and that will automatically make it more expensive. No free lunches in physics.

[–] Kelsenellenelvial@lemmy.ca 2 points 1 year ago

My presumption is that the desalinated water might be cheaper than tap, but would still require further processing to be considered potable, which would raise the price on par or above conventionally sourced tap water. I imagine there’s a lot of costal areas though with ready access to saltwater and minimal access to freshwater where it’s worthwhile.

[–] glimse@lemmy.world 2 points 1 year ago

Truly the most reposted link in lemmy history

[–] AceFuzzLord@lemm.ee 0 points 1 year ago

Cheaper than tap but at a 500% markup for CoNvEnIeNcE! You know that if it's cheap, the large black scarf buckets (c*pitalists) will come in and force the prices to go up until nobody can afford it.