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Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

utexas.edu

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Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#51

Post by BillyMaize »

ajuc wrote: post #47
usablebytes wrote: post #39

Why do we usually utilize science to fix the wrong problem? Shouldn't we be making more efforts on 1) Growing more trees 2) Reducing environmental pollution 3) Controlling human population ???

There's more than 8 000 000 000 of us, if everybody were just doing the thing with the greatest priority it would be very ineffective division of work. Like digging one hole with 1000 people. As a humanity we can (and should) multitask, especially when it comes to science and inventions, because you never know which seemingly pointless path can lead you to a great breakthrough. Imagine everybody since antiquity worke…

The population of the world is slightly under 7 billion.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#52

Post by andrewflnr »

usablebytes wrote: post #39

Why do we usually utilize science to fix the wrong problem? Shouldn't we be making more efforts on 1) Growing more trees 2) Reducing environmental pollution 3) Controlling human population ???

There is actually a pretty decent amount of work going into better building materials and alternatives to wood-pulp paper. The science involved in growing trees is pretty well established. Since there were trees, in fact. :) Getting more trees is a social problem.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#53

Post by CapitalistCartr »

BillyMaize wrote: post #51
ajuc wrote: post #47

Earlier quoted context omitted.

There's more than 8 000 000 000 of us, if everybody were just doing the thing with the greatest priority it would be very ineffective division of work. Like digging one hole with 1000 people. As a humanity we can (and should) multitask, especially when it comes to science and inventions, because you never know which seemingly pointless path can lead you to a great breakthrough. Imagine everybody since antiquity worke…

The population of the world is slightly under 7 billion.

The US Census bureau says 7.097 Billion. They estimate that the world population exceeded 7 billion on 12 March 2012.

https://www.census.gov/popclock/

http://www.worldometers.info/world-population/

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#54

Post by Retric »

haldujai wrote: post #38
rflrob wrote: post #33

Earlier quoted context omitted.

>Additionally their flow rate is 0.4 microlitres per minute, this would equate to needing 625 000 channels for one pass only to get 250mL / min. Scaling for microfluidics isn't simply using a larger pipe size, microfluidic devices largely operate with minimal forces and a Reynolds number of 1, that doesn't hold as you get larger. What about parallelization? Are there any obvious downsides to simply having lots of the…

Yes, parallelization is actually the currently accepted means of increasing throughput, you'll see diagnostic devices with thousands of channels. The reason it isn't appropriate here is because of the complexity, the design is easy, you make a radial pattern of inlets with the splits towards the middle so you can combine outlets of the same type. Construction is relatively easy as well. The problem comes from the num…

An idea that may be useful is to place this upstream of a reverse ausmosis filter. That way the inlets and outlets can feed into the same area. You would still need to separate the inlet and fresh water outlet far enough from each other and you would need to setup the pressure differential but you might be able to do that by keeping the water moving in the high salinity tank.

The advantage being reverse osmosis is more efficient when the salinity difference is smaller. Still I don't think the added complexity is going to be worth slightly lower energy costs.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#55

Post by ajuc »

BillyMaize wrote: post #51
ajuc wrote: post #47

Earlier quoted context omitted.

There's more than 8 000 000 000 of us, if everybody were just doing the thing with the greatest priority it would be very ineffective division of work. Like digging one hole with 1000 people. As a humanity we can (and should) multitask, especially when it comes to science and inventions, because you never know which seemingly pointless path can lead you to a great breakthrough. Imagine everybody since antiquity worke…

The population of the world is slightly under 7 billion.

Thanks.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#56

Post by aroch »

Luyt wrote: post #49
Ellipsis753 wrote: post #28

"The new method requires so little energy that it can run on a store-bought battery." What a silly measurement. I can buy a laptop battery or a car battery at a store. Also it does not give any idea of how much water could be produced from the battery. A teaspoon per battery probably isn't too great. (Although at the moment they get only nanoliters of salty water from it of course).

A similar silly unit is used to measure 'green' energy: "This windmill can power 10.000 households". As if we're too stupid to understand a kWh figure.

It's nothing to do with being smart or stupid, 10K homes is a more descriptive number (more easily visualized) than kWh for describing energy production to the general populace.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#57

Post by gabemart »

sbierwagen wrote: post #25
efsavage wrote: post #19

I don't put much stock in those who make claims like "the next world war will be over water", because we have a massive supply of water (the ocean) and a massive supply of energy (the sun) to power whatever we need to do to make it drinkable. A floating desalination plant powered by an x000-acre floating solar platform, pumping clean water back to shore, and dispersing slightly saltier water across a wide area, doesn…

The process doesn't even have to be super efficient Economics are important. We didn't go back to the moon because it was too expensive, and we're not going to see massive-scale desalination because it's also too expensive: http://physics.ucsd.edu/do-the-math/2012/10/the-energy-water... California uses 46 billion gallons of water per day. Supplying 25% of this via desalination would require 36 GW of thermal-equivalen…

Agricultural requires water. But much of the "requirement" is a product of the ready supply and low cost of that water. If fresh water prices rise, the more water-intensive agricultural crops are grown less and become more expensive.

I wonder what the water-used-to-calories-produced ratio is for something like lettuce compared to something like corn or beans. I imagine it's a good number of orders or magnitude higher.

In other words, an increase in the price of fresh water does not necessarily significantly increase the price of feeding yourself, it significantly increases the price of water-intensive crops and likely increases the demand for less water intensive crops.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#58

Post by brownbat »

> "The new method requires so little energy that it can run on a store-bought battery."

We currently have techniques that require no additional power (just using the sun), but almost every desal operation uses a powered method.

Power consumption isn't the only factor here. A low power technique that has throughput per area equivalent to solar stills is just worse than all available alternatives.

If you made a device that turns the briny sludge byproduct into fuel or some other consumable, that would be amazing.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#59

Post by tsotha »

ars wrote: post #43
tsotha wrote: post #40

Earlier quoted context omitted.

But municipal water typically comes from rain or snowfall. The distillation has already been done.

You wish. No, it usually comes from a river. And guess where the waste water from a sewage treatment plant goes? Right back into the same river, only downstream. And that's where the next city down the line picks it up. That water gets recycled multiple times on the way to the ocean, by each city on the river. That's not a bad thing! But the water can hardly be called distilled.

Where I live the river water comes from snow packs. And nobody's allowed to discharge treated sewage into rivers. Gross.

Re: Chemists Work to Desalt the Ocean for Drinking Water, One Nanoliter at a Time

#60

Post by HCIdivision17 »

jonmrodriguez wrote: post #30
HCIdivision17 wrote: post #27

Earlier quoted context omitted.

I had an electrical engineering old timer explain the misconception as the Current Push Theory. (His industrial war stories were pretty good.)

Googling for "Current Push Theory" only gets 5 results, none of them relevant: https://www.google.com/search?num=100&q=%22Current+Push+Theo... Can you please define the Current Push Theory?

The basic idea was that you can't put a 5kW drive on a 2.5kW motor: it would shove too much power into the motor and break it. This is not quite at all how those systems work.
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