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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

#91

Post by oceanplexian »

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?

The short answer is all those problems have already been solved.

Israel desalinates 75-85% of its drinking water. The problem is political and economic dysfunction.

California for example could be doing widespread desalination with nuclear power and technology from the 1970s. They could also greatly expand reservoirs and waterways, but don’t do it. Very similar to Rome in the 400s, when people were using aqueducts built by a past civilization but lost the ability to construct them.

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

#93

Post by ceejayoz »

threwrfaway wrote: post #84
ceejayoz wrote: post #67

Earlier quoted context omitted.

Brine doesn't necessarily behave the way you imagine. https://en.wikipedia.org/wiki/Brinicle https://en.wikipedia.org/wiki/Brine_pool

You can dilute the brine in a facility before disposing.

Go on. With what?

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

#94

Post by xyzzyz »

ceejayoz wrote: post #48
xyzzyz wrote: post #44

Earlier quoted context omitted.

Brine is very easy to dispose of: you just pump it back to where it came from. Solid crystalline salt, on the other hand, is a hassle.

> Brine is very easy to dispose of: you just pump it back to where it came from. Easy, but not necessarily good for the spot you're pumping concentrated salt back into.

Maybe, but dumping crystalline salt is even worse to the spot you’re dumping it on.

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

#95

Post by ashdksnndck »

ceejayoz wrote: post #48
xyzzyz wrote: post #44

Earlier quoted context omitted.

Brine is very easy to dispose of: you just pump it back to where it came from. Solid crystalline salt, on the other hand, is a hassle.

> Brine is very easy to dispose of: you just pump it back to where it came from. Easy, but not necessarily good for the spot you're pumping concentrated salt back into.

If you use fat pipes that go a decent distance from shore, diluting your brine with ocean water, you’ll have a negligible impact on the ocean. The problem is if you dump lots of brine in shallow waters. Old designs did have that flaw, but it’s not that difficult to design around this constraint now that we know about it.

IMO this is an issue where NIMBYs are using environmental concerns as a smokescreen to block new desal plants from ruining the vibe at their beachfront property. Rhymes with the opposition against offshore wind farms.

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

#96

Post by xyzzyz »

cyanydeez wrote: post #90
xyzzyz wrote: post #44

Earlier quoted context omitted.

Brine is very easy to dispose of: you just pump it back to where it came from. Solid crystalline salt, on the other hand, is a hassle.

yeah, if you like to kill everything in a few 100 feet radius and kill some more in the zone of reliance. this is delusional ecological

Brine might be bad to the place you dump into, but crystalline salt is even worse.

Overall though, it’s just such a tiny concern. Ocean is huge. If we kill everything in a 100 foot radius, that’s 0.0000000008% of the ocean being destroyed. Less than a drop in a bucket.

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

#97

Post by numpad0 »

Joker_vD wrote: post #83
ceejayoz wrote: post #58

Earlier quoted context omitted.

> The brine came from the ocean. Sure, and enriched uranium comes from the ground, but that doesn't mean it's safe to dump it back in after the enrichment process! > So just dilute it back to close to ambient salinity using municipal waste water… Wouldn't it generally be easier to process that municipal waste water, as is already fairly common?

> Sure, and enriched uranium comes from the ground Uranium can also come from the ocean water (there is, apparently, quite a lot of it in there, relatively speaking). Japan experimented with the technology in the nineties, but it really was much cheaper to just mine it from the ground, so they abandoned it.

Japan is also barred from doing own enrichment, being a non-nuclear state. Though, there nevertheless is a dormant set of requisite facilities.

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

#98

Post by card_zero »

xyzzyz wrote: post #94
ceejayoz wrote: post #48

Earlier quoted context omitted.

> Brine is very easy to dispose of: you just pump it back to where it came from. Easy, but not necessarily good for the spot you're pumping concentrated salt back into.

Maybe, but dumping crystalline salt is even worse to the spot you’re dumping it on.

I wonder. It would have to dissolve, a big block of salt would take a while, kind of like the erosion of cliffs where the salt comes from in the first place. Eh, I guess you're right though, the fish wouldn't like that at all.

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

#99

Post by xyzzyz »

galaxyLogic wrote: post #55
xyzzyz wrote: post #44

Earlier quoted context omitted.

Brine is very easy to dispose of: you just pump it back to where it came from. Solid crystalline salt, on the other hand, is a hassle.

I think I read somewhere that salt can be used as energy storage medium? So we could get both water and batteries for renewal energy.

It’s about thermal storage, you don’t use table/sea salt for that, and you don’t need a lot of salt, because the salt is in a closed loop; it’s not being consumed.

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

#100

Post by otterdude »

ajb wrote: post #4

There is a fundamental minimum amount of energy needed to desalinate: you can't take less energy to do it,than you could gain back (from osmotic pressure) if you allowed the desalinated water to expand a cylinder containing the residual brine. This is large. This paper is a thermal method, so it doesn't have an electricity input, but to justify their efficiency claim, they should really compare against what you could…

Thermal methods require energy, it seems like this substrate is effective at maintaining its solar-thermal absorbing properties better than a material that will attract salts

> Testing their solar-thermal desalination technique using samples of water from the Pacific, Atlantic, and Indian Oceans, Guo and his team were able to make the surface self-cleaning. In other words, it extracted freshwater and directed the remaining salts to the passive region where they could be later collected without reducing the panel’s efficiency.

This is not "large" this is a moderate improvement. Albedo is likely only marginally affected, and the solar power input over area is the same.

Depending on this cost of this process it could very likely be a wash in terms of NPV

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