190
MIT’s New Desalination System Produces Freshwater That Is “Cheaper Than Tap Water”
(scitechdaily.com)
this post was submitted on 06 Oct 2023
190 points (94.4% liked)
Solarpunk technology
2373 readers
14 users here now
Technology for a Solar-Punk future.
Airships and hydroponic farms...
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
I'm worried we will take too much at once. What happens when these machines are running? How do we ensure the water is placed back correctly? You can't just dump it back in desalinated if everyone is doing it. Thats millions of gallons of fresh water. I'm not sure what the effects are, I just know that they will be and we'll have to figure that out too.
You are drastically underestimating how much saltwater the earth has.
Yeah, here are some numbers for scale:
There are about 1,335,000,000km^3 of water in the ocean. Humans use around 4600km^3 of water annually. That is only 0.000345% of the volume of the ocean.
But have you considered we fuck up the environment every where we go? I get theres a lot of salt water but nobody is going to convince me there are no consequences for mass desalination. Nothing is consequence free here. There is a price for everything we take.
Do you think the salt is just going to get loaded on rockets and sent to the sun?
The earth is a closed system, the salt and the water will eventually make it back to the ocean.
No, I don't think that. I think we will desalinate the ocean enough for it go up by the few degrees it needs to kill most ocean life. Probably over the span of a few decades. But go off on how this is consequence free i guess.
Again, you grossly underestimate the sheer volume of our planet’s oceans.
Again, climate change is effecting the ocean the most. If it is already strained, and for the next 100 years we start mass desalination in developed nations, what do you think will happen to the already rising and deadly temperatures? If they are already approaching dangerous levels, and desalination raises the temperature, what will happen? I'm not misunderstanding here, I'm telling you once this picks up en masse there will be consequences.
Yep so u pump the salt water into the desert where evaporation makes salty and the water evaporates into the atmosphere.
With desalination, don't worry about the freshwater. Worry about the brine.
Freshwater from seawater isn't going to do anything more than is currently happening with however an island gets its water.
But brine? That needs to be carefully reintroduced to the ocean (or evaporated on salt flats to farm salt).
The point is, this is a solution to a problem now and probably in the near future. 100% of the world won't be desalination. This is literal drops in the bucket compared to other resources we take from the earth that are impossible to replenish.
Worry not, the ocean's water levels are about to get A LOT HIGHER thanks to all the melting glaciers!
And since glaciers are freshwater, all the salt can be dumped there. Win win.
(Hoping the /s won't be needed buuuuut...)
Hahahahaha.... hahaha.... ha... :(
There are concerns, but all of our water makes it's way to surface systems or rivers and eventually the ocean now already. I don't think we will be dumping the fresh water we just desalinated directly back....it will be used, to though the sewerage system, and then make its way back the way our water currently does.
That said, there are valid concerns around salt concentration if we dump the salt back, and heat can be an issue as well.
Issues like that worry me. The oceans are already heating up and killing the wildlife. Not that we have much of a choice as water demand rises, but we should be analyzing and watching carefully as we desalinate. We probably won't and in 100 years there will be headlines like "Ocean water boils sea creatures slive! Who would have seen this coming?"
Right now the salinity of the ocean is decreasing because of the polar ice melting. So to some extent, taking freshwater out of the ocean should be beneficial to preserving its ecological conditions.
It depends on how the brine is reintroduced, which I am sure will be up to the company or individuals will have some sort of collection for households. But salinity going down raises ocean temperatures, as I've mentioned in a comment down below so I won't really restate it gere.
Pulling more out will only help fight rising sea levels. You don't need to worry about it going back in, it's not like everyone's gonna start dumping millions of gallons of freshwater into coastal estuaries or anything.
plus the concentrated brine from desalinization needs to go somewhere - worrying about taking too much salt from the ocean probably ranks lower than worrying about the brine being disposed of incorrectly. I like HopeOfTheGunblade's idea of mixing it with the cleaned-up wastewater, there's a sort of balance there.
Decreased salination leads to hotter oceans. Mass desalination combined with the reduced salination from melting ice caps could pose serious threats to already fragile ocean life. Humanity is always looking for a savior instead of striving for balance.
I'm not sure how the first part is relevant/practical, given that the complaints about desalinization plaints is the increased salinity due to the hypersalinated waste produced after the desalinizated water is extracted. Wouldn't desalinization plants' hypersalination counteract the hyposalination caused by the glaciers rather than exacerbate it (obviously this would be difficult to not have the waste concentrated and cause local environment issues)?
Take out salt water -> separate freshwater from brine -> use the fresh water -> combine cleaned wastewater with brine -> reintroduce. Seems pretty balanced to me, at least by human standards. The salt isn't dumped down a mineshaft.
Desalinization plants dumping the brine straight back into the ocean, raising the concentration of salt in the region and poisoning the local wildlife, that's something I've heard of happening, but it sounds like this system is intended to be way smaller, operated at a household level. People dumping the brine into the dirt, sterilizing it, or in local streams could be a problem.
I don't know, it just seems like desalinization (not necessarily this version) is more of an effort towards balance than endlessly draining aquifers or damming rivers.