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New method turns ocean water into drinking water, without waste

rochester.edu

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Re: New method turns ocean water into drinking water, without waste

#31

Post by Nifty3929 »

Animats wrote: post #29

The paper: [1] They're still at lab scale in glass. They haven't built a usable system, even a small one. The big claim here is that it doesn't clog; capillary action moves the salt out of the active area to another area, where some yet to be developed mechanism removes it. That needs to be demonstrated. If they can come up with something that runs for years without clogging or replacing the active material, that's a…

It reminds me of how the Panama canal was built, and actually the first major attempt failed and they gave up. What they learned for the second attempt was that digging was not the hard(est) part to solve - it was how to move the dirt! So much dirt!

Great book on this BTW: Path Between the Seas. I couldn't put it down.

Re: New method turns ocean water into drinking water, without waste

#32

Post by wizzwizz4 »

boxed wrote: post #18
kaonwarb wrote: post #3

This reads like hyperbole: > The brine byproduct wreaks havoc on sea life when it’s deposited back into the ocean by raising the salt level and lowering oxygen in the water. Managing return of concentrated brine should be entirely tractable in the literal ocean.

I mean.. we really want to permanently desalinate the ocean somewhat too so putting the brine back seems kinda stupid. Put it on land, let it dry, sell some as table salt and dump the rest into abandoned mines.

Excellent idea! The largest abandoned mines I'm aware of are salt mines, which… hang on.

Re: New method turns ocean water into drinking water, without waste

#36

Post by Jblx2 »

tdb7893 wrote: post #25
Jblx2 wrote: post #21

Earlier quoted context omitted.

>Persian Gulf has 20% more salt in water because of the humans I would like to read more about this from an authoritative source.

Through the magic of Googling "Persian Gulf salinity" it seems like it's more that it's a shallow Gulf in a dry area so it has significant evaporation. Desalination does effect it but it's only a few percent of the total evaporation (which is still surprisingly big) and doesn't sound like the main driving factor or an imminent ecological concern. https://www.frontiersin.org/journals/marine-science/articles... https:/…

I thought the HN-way was to be more charitable than just directly calling out obvious bullshit.

Re: New method turns ocean water into drinking water, without waste

#38

Post by casey2 »

LogicFailsMe wrote: post #34

So crazy question: take a dehumidifier, attach some solar panels, and deploy at scale for non-potable water suitable for crop irrigation anywhere that isn't a desert. Does it work? And if not, why?

What do you mean work? No, because there is no single dehumidifier on the market that will get you enough water, so you are out $80 grand, you could have just paid for water delivery.

Re: New method turns ocean water into drinking water, without waste

#39

Post by mrguyorama »

LogicFailsMe wrote: post #34

So crazy question: take a dehumidifier, attach some solar panels, and deploy at scale for non-potable water suitable for crop irrigation anywhere that isn't a desert. Does it work? And if not, why?

It "works" in the sense that this is what 99% of "Get water from air" scams are.

The reason it doesn't actually work is that it is extremely inefficient. Getting water to condense requires you to somehow reject massive quantities of heat. That's fundamental to physics.

Also, literally anywhere a dehumidifier is reasonably effective, is humid and usually doesn't have such dire water problems. Deserts have extremely low humidity and dehumidifiers working in a desert will produce very little water.

Even a good humidifier in a humid environment is burning KW to generate on the order of ten liters of water a day.

There are a couple places on earth that are essentially deserts but have an early morning humid fog roll through regularly, and those places figured out capturing that water in the air long long before we invented the refrigeration cycle.

It is literally cheaper to desalinate.

Maybe you could build giant greenhouses to fill with sea water and let the sun evaporate the water and collect that with a dehumidifier? Still absurdly inefficient. Water has such an obscene specific capacity for heat that any thermal avenue of separating it from something else will use immense energy.

Re: New method turns ocean water into drinking water, without waste

#40

Post by LarsAlereon »

LogicFailsMe wrote: post #34

So crazy question: take a dehumidifier, attach some solar panels, and deploy at scale for non-potable water suitable for crop irrigation anywhere that isn't a desert. Does it work? And if not, why?

It takes too much energy and produces water too slowly to scale. In general any area with sufficient moisture in the air to explore this also has easier access to rain and ground water.
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