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Comment by kaycebasques | Hacker News Reader

Exciting! This wouldn't help with problems like lead in the water, would it?

I think it’s meant to provide an emergency source of water for drinking.

You wouldn’t want to use this for a large population for a prolonged period of time because you’d have trouble disposing of all the salt waste.

Figuring out how to handle the salt byproduct is a critical part of long term desalination.

How much salt are we talking? A large portion of the country coats all paved surfaces with it during and after every snow/freezing rain. Shut down the salt mines if need be.

Just contaminate the entire country with random substances. What could possibly go wrong?

I agree your perspective, but the salt could be cheaply tested at various stages for whatever contaminants you’re afraid of. How much testing do you think is done on the lettuce you eat? Or the beef you buy? Or the flame retardants in your carpet, clothing, flooring, and furniture? What about the bpa alternatives in all good grade plastics? What about Teflon’s and other forever chemicals? The answer is only as little as everyone can get away with because the people with authority don’t have the means to deal with their actual workload or the fallout of shutting down massive companies indefinitely. Ignorance ain’t bliss, but it may be better than knowing I’m powerless against the greedy fascists mortgaging the survivability of earth for yachts, drugs, and vanity today.

Maybe we can place the effluent at the base of a glacier so it buffers the fresh water coming off the melting glaciers and keeps the ocean running? /s

I don't see what the issue would be of just dumping it back into the ocean if you find no better use for it?

Can you pack it and sell it?

That’s a looooooot of salt, way more than you’re ever gonna use up through food, and it’s heavy. And corrosive.

1,000,000 humans require 4,000,000 liters of water daily. Seawater is 3.5% salt (35g/l), giving us 140,000,000g of salt. If we assume NaCl, with a density of 2.17g/cm3, that gives us 64,500,000 cm3 of salt, or 64.5 m3. I am getting a range of capacities on dump trucks, but somewhere on the order of 10m3 per truck. So 6-7 dump trucks dropping salt into the middle of nowhere. That does not sound like an infeasible problem for maintaining 1e6 humans?

Expecting Cunningham’s Law to show I goofed the math.

Humans require a lot more than 4L daily if you count sanitation, food production, and so on. But it’s still true that ultimately it’s not a lot of water if we wanted to put our minds to it.

I think your main issue is that the NaCl doesn't come out in a pure crystalline form. It's a higher concentrated brine but still contains an awful lot of water.

Nuts, that is an excellent point. I am failing to find the outflow concentration of salt, but you are correct that the output is likely to be only mildly concentrated (eg 7% salt). For all I know, it take an order of magnitude more energy to emit pure salt rather than a brine. Total amount of salt is not insurmountable, but the volume of output would be challenging quickly without enormous evaporation pools.

My understanding is some US salt flats are actually restored on annual basis to facilitate high speed racing on them. So if you didn't mind trucking it a very long distance, they'd be happy to have you dump it out there.

You have 4 liters of water per person? That's what, only drinking?

Average household water use in 100-200 liters per day.

Put it on a rocket ship and fly it into the sun of course.

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