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New method turns ocean water into drinking water, without waste

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

#151

Post by cornholio »

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…

Focusing on pure energy efficiency might be missing the point of economic efficiency.

An RO desalination plant needs electric energy to drive the pumps, which might be generated by panels which are 15-20% efficient. So, if you can have cheap thermal desalination panels, they come out ahead even if 6x less energy eficient, you avoid the whole expensive and fragile desalination plant and you gain a low skill, distributed setup.

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

#152

Post by somenameforme »

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.

It's about 3 parts per billion. Uranium is about $85/pound, so you'd need to be able to completely process/extract about 40 million gallons of saltwater for $85 to break even. The real cost there is orders of magnitude higher. It's one reason the claim about the Earth having vast amounts of uranium is quite disingenuous. The amount of cost efficient accessible uranium is only enough to last ~1 century at current consumption rates. If nuclear energy scaled up significantly, we'd run out in a matter of decades if not less, or we send the price of uranium skyrocketing and the price arguments would need to be significantly adjusted.

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

#154

Post by fsck400 »

mkl wrote: post #109
eimrine wrote: post #17

Earlier quoted context omitted.

Persian Gulf has 20% more salt in water because of the humans which are throwing the oversalinated waste back into the sea. Dehidrated salt may be a big deal for some areas because of no waste into input.

The brine is waste, and the dehydrated salt is also waste. Maybe dry waste is better, but it's still waste.

Lavoisier’s “Traite elementaire de chimie” refers to water electrolysis.

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

#155

Post by Someone »

ashdksnndck wrote: post #95
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.

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…

> 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.

I think that problem was known (and discarded as not important) when the first serious water desalination plants were built.

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

#156

Post by kortilla »

xp84 wrote: post #141
ashdksnndck wrote: post #95

Earlier quoted context omitted.

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…

I can probably be convinced pretty easily with some evidence of that, but you’ll never convince the contingent who is convinced it’ll kill sea life at any concentration or location, so, being able to shut them up by saying “we have no wastewater, we load rail cars with crunchy salt and use it for stuff” still has value.

The goalposts will just shift to attack that excess salt instead. It’s like all of the FUD about datacenter water usage while people shove almonds in their mouths.

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

#158

Post by ssl-3 »

asdff wrote: post #119
qurren wrote: post #52

Earlier quoted context omitted.

Why? Just build mountains out of it and maybe even open a salt-ski park in the tropics for people who don't have snow.

There are salt mountains lining most midwestern freeways as it is for winter.

Assuming my constants (35g/kg of salt in seawater, 650k tons of salt dumped by the state of ohio every year, 81 gallons per day of individual domestic water usage) are correct and my napkin math isn't completely buggered, and if we look at the salt as a primary product instead of just waste:

Ohio DOT's use of road salt would allow for fresh water to be provided for somewhere in the neighborhood of 160,000 people.

On one hand, that's nowhere near enough people; it's a small drop in a giant thirsty bucket of water consumption. So we'll still need salt mountains, salt re-distribution vessels, and/or other ways to deal with excess salt.

On the other hand, 160k is a lot of humans. So perhaps we should look into doing things like this anyway.

(But we probably won't. Ohio gets road salt primarily from a mine under Lake Erie that has a very conveniently-located terminus near downtown Cleveland. The mine directly loads trucks, freight trains, and ships...and it's near the point of use already. It's pretty efficient.)

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

#159

Post by numpad0 »

redsocksfan45 wrote: post #131
numpad0 wrote: post #97

Earlier quoted context omitted.

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

You're wrong. Japan does do their own enrichment, 150k SWUs at Rokkasho with plans to bring that up to 500k SWUs a year soon. If they chose to make.bombs instead of fuel, they could make dozens a year.

That's the dormant plant. Rokkasho-mura plant is officially incomplete for decades, doing tests and upgrades without actual production.

If you think otherwise and you're not wrong, and I think you ARE not mistaken since this isn't the first time someone other than myself mentioned it here, that means they're making bombs because we in Japanese public aren't told about it. There has only been just some routine commentaries from local mayors at most.

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

#160

Post by dyauspitr »

AlexandrB wrote: post #112
gaiagraphia wrote: post #88

Earlier quoted context omitted.

I love projects like this. A shame the west has handed over the baton to the Chinese and Saudis when it comes to actually being daring with megaprojects. Some over stuff whhich are cool to read about: Redirecting Siberian rivers into Central Asia https://en.wikipedia.org/wiki/Northern_river_reversal Redirecting Congo basin rivers to replenish Lake Chad https://en.wikipedia.org/wiki/Lake_Chad_replenishment_projec... F…

The Saudis aren't "daring" with megaprojects. They're fucking[1] stupid[2]. Saying their megaprojects are "daring" is like saying I'm "daring" for claiming I'm going to build a catapult that will launch me to the moon. [1] https://en.wikipedia.org/wiki/Trojena [2] https://en.wikipedia.org/wiki/The_Line,_Saudi_Arabia

That’s what daring means. You try things that do not guarantee success. I remember a decade of people shitting on Dubai for all of the crazy projects it was building. It really paid off for them (pre Iran war). They made something out of nothing and still are. What’s stupid about a kilometer high tower? It’s fucking awesome.
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