this post was submitted on 28 Sep 2023
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Engineers at MIT and in China are aiming to turn seawater into drinking water with a completely passive device that is inspired by the ocean, and powered by the sun.

In a paper appearing today in the journal Joule, the team outlines the design for a new solar desalination system that takes in saltwater and heats it with natural sunlight.

The researchers estimate that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters of drinking water per hour and last several years before requiring replacement parts. At this scale and performance, the system could produce drinking water at a rate and price that is cheaper than tap water.

https://www.cell.com/joule/fulltext/S2542-4351(23)00360-4

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[–] Lucidlethargy 13 points 1 year ago (2 children)

It's just a giant plastic bag. They catch the runoff with a giant cup.

[–] [email protected] 3 points 1 year ago (3 children)

As soon as I saw the words “powered by the sun” in the synopsis, I knew what this was. I learned this during survival training, it’s a great way to turn piss (or any other undrinkable water) into clean water. And yeah, all you need is some plastic and a cup. Let the water evaporate (power of the sun) and collect the droplets in something. Had no idea that needed a science paper.

Here’s the problem with desalination, tho: what do you do with the leftover super-brine? It’s pretty gnar stuff, like almost poison. Wide-scale desalination would produce tons of it every day. Most solutions i’ve heard are like “just dump it back in the ocean!” Which, yeah, how could that ever go wrong?

[–] [email protected] 3 points 1 year ago

Did you read the article? You reject the slightly saltier water.

[–] [email protected] 1 points 1 year ago

On a commerical scale the super brine may be economical to harvest the lithium. I know systems were getting close to being able to economically extract lithium from sea water. A more concentrated solution should make it easier.

[–] [email protected] 0 points 1 year ago (1 children)

Also, this would be distilled water? Or do they have some process to add the necessary minerals afterwards? I didn't see anything about that. Because drinking distilled water isn't exactly good for you.

[–] [email protected] 4 points 1 year ago (1 children)

There's nothing particularly wrong with drinking distilled water as long as you are getting enough minerals and electrolytes from the rest of your diet.

[–] [email protected] 1 points 1 year ago

True. However I would think that a system such as this would be used mostly in developing countries where getting all those minerals from your diet is not a given.

[–] [email protected] 2 points 1 year ago

Exactly, imagine how much water can you gather in a hot climate that doesn't evaporate untilyou get it or grow algae/fungi/protozoa/things that aren good for you.