Spray pond: Natural sunlight is used to evaporate and concentrate the salt water in seawater.
Saltworks Technologies
Energy-saving process uses free heat to desalinate seawater.
A Canadian startup has built a pilot desalination plant in Vancouver that uses a quarter of the energy of conventional plants to remove salt from seawater. The process relies on concentration gradients, and the natural tendency of sodium and chloride ions--the key components of salt--to flow from higher to lower salinity concentrations. If the system can be scaled up it could offer a cheaper way to bring drinking water to the planet's most parched regions while leaving behind a much lower carbon footprint than other desalination methods.
"We've taken it from a benchtop prototype to a fully functional seawater pilot plant," says inventor Ben Sparrow, a mechanical engineer who established Saltworks Technologies in 2008 to commercialize the process. "The plant is currently running on real seawater, and we're in the final stage of expanding it to a capacity of 1,000 liters a day."
Today most desalination plants are based on one of two approaches. One is distillation through an evaporation-condensation cycle, and the other is membrane filtration through reverse osmosis. But both options are energy-intensive and costly.
Saltworks takes a completely different approach based on the principles of ionic exchange. The process begins with the creation of a reservoir of seawater that is evaporated until its salt concentration rises from 3.5 percent to 18 percent or higher.
The evaporation is done in one of two ways: either the seawater is sprayed into a shallow pond exposed to sunlight and dry ambient air, or seawater is kept in a large tower that's exposed to waste heat from a neighboring industrial facility. The second approach is used in the commercial-scale plant. The concentrated water is then pumped at low pressure into the company's desalting unit along with three separated streams of regular seawater. At this point the most energy-intensive part of the process is already over.
Inside the desalting unit, which in the pilot plant is about the size of a microwave oven, specially treated polystyrene bridges connect two of the regular seawater streams to the highly concentrated stream. Positive ions (largely sodium) and negative ions (largely chloride) are drawn by diffusion through the polystyrene, which has been chemically treated to manipulate specific ions, from the concentrated steam into the weaker ones. One bridge is treated to allow only positively charged ions to pass, while the other bridge only allows negatively charged ions to pass. But both allow other ions in salt water, including magnesium, calcium, sulfate, and bromine ions, to pass through. "The negatives all flow in one direction and the positives all flow in another direction," Sparrow says.
Battery draws power from salinity difference between freshwater and saltwater.
Saudi Arabia's newest purification plant will use state-of-the-art solar technology.
Whoah, tell that to the millions of people in places like India who are in desperate need of fresh water.
As for the technology, I like the idea of using sunlight and/or waste steam to lower the energy costs, but I'm confused at why the company doesn't seem to be condensing the water vapor produced from the evaporation.
On a side note, did you see the new release about a power plant (~4kW though) in Norway that uses freshwater diffusion into sea water to produce electricity? Obviously, if such a plant were to be built in India, you would see millions of protesters because the idea of using fresh water to generate electricity is a bad idea for most parts of the world.
The desalination of water is not going to help a massive country like india very much. India does have a big ocean on it's doorstep called the Indian Ocean which represents a massive growing area. If you take away the agricultural demand for water then there would be enough fresh water to go around.
This is a great idea and it saves a lot of energy in the process. To scale it up, call Governor Arnold Swartznegger and ask him to lease you about 10,000 acres of land east of San Diego near Mexacali, then build a path to the bay so you have a source of sea water. All that dead space could be used to process water for US citizens.
San Diego, Orange County, LA County, parts of Arizon and Texas - not just developing countries all need fresh water.
The process could introduce more agriculture to the Mexicali area and can be scaled up even more throughout Mexico's coastlines and on the Baja Pennisula. By employing locals, you may even have a chance at impacting the drug cartels because there would be a source of legal jobs.
>>> the absolute BEST desalinator ever invented >>>
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I think that the absolute BEST desalinator ever invented is this $30 device that uses ONLY the SUN without any other energy source!
http://offtopicnews.blogspot.com/2009/02/un-geniale-dissalatore-low-tech-da-30.html
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Re: >>> the absolute BEST desalinator ever invented >>>
Here is the direct link:
Sun powered Desalinator
Cool! Why isn't this taking off? Could it be because it's too simple?... no way to make whole populations dependent on centralized govt. or infrastructure?
Reminds me of the debate in this country a century+ ago over AC v. DC electrical power.
Or of the Rotary (& UN) effort to end Polio. That effort may have been beneficial and well intentioned, but if ending the biggest child-killer worldwide was the goal, then attacking diarrhea would have been far more economical.
But... then the patent holder of the oral polio vaccine wouldn't have been able to 'sell' so many dosages.
Think about it.
There was an episode in Survivorman and Man vs Wild where each of our superhero's needed water.
Each acquired a piece of plastic somehow (gift from heaven perhaps?) and then proceeded to make a similar evaporation unit whereby they were able to distill water from their own urine thus surviving to fight another episode.
Hey it worked and Saran Wrap is now a major sponsor!
;)
One more great innovation to help the world.
I applaud the invention and wish the company all success. Each day I find joy in the fact that the citizens of the world find innovative ways to reduce our dependency on traditional energy sources.
Technically this is a beautiful, simple idea. one of those things that you wonder, why hasn't this occurred to anyone before.
Whether this will prove inexpensive in common practice, I don't know. But consider the possibilies in parts of Baja, the west coast of South America, near the Atacama desert and in Peru, West Africa, Arabia, Western Australia, etc.. A thousand gallons a day could enable a small fishing village, grow a few shade, fruit trees with shower water, maybe a raised bed vegetable garden. Maybe not world changing, but life changing to hundreds of thousands, and making the world a little greener.
I have relatives living in the Atacama (mines) who also have a seaside "cabin" (they bring drinking water in.) A solar powered system (way off the grid) could make a huge difference.
just need thin PV to come down in price now also.
And nutrients to the sea? The salt water would be returned, but the sea has too many nutrients too many places. rivers are discharging nitrogen fertilizers, phosphates etc causing deoxygenating algae blooms. That and just plain pollution asnd trash (along with overfishing) is what are making the seas sick. Any conceivable desalination would be neutral.
It looks suspiciously like the solar still the army and I am sure others have been using for longer than I have been around, It works even better if you dig a hole in the sand and let the condensate fall into a nice cool place where it will not reevaporate. This 'great new thing' falls into the same category as solar water heaters - what a concept
That this type of work is being done is very encouraging to me. Combined with unlimited renewable energy, desalination could help feed every person on the planet. Accelerating technology will give us this possibility sooner than most people think. The political scumbags on both sides of the spectrum will slow it down, but I think we will still get there.
Side Questions for the year 2030:
When energy and clean water are cheep and abundant, will "they" allow me to waste it?
When they can cure cancer, will I be allowed to smoke?
sounds like quite an exhilarating life- smoking and letting the tap run a long time- i know that's what I will be looking forward to
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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DJTal
154 Comments
Ocean fertilisation.
We do not need fresh water to produce more food. We wouldn't need to waste so much precious fresh water for irrigating crops if we tried to produce more food from the oceans. The decision to produce so much food from the land drives the need for the unsustainable intensification of farming. The intensification of farming reduces farm food prices, then just locks us into a vicious cycle of dependency on the land for everything we need, with subsequent natural habitat damage. The solution has to be to break out of this and to put more nutrients back in the oceans. There is plenty of space, water and nutrients just waiting to be unlocked in the oceans. A diet higher in seafood would be better for our health and it would mean we'd be supporting a bio-diverse habitat for producing food. It's win win all round.
Reply
lasertekk
146 Comments
Re: Ocean fertilisation.
The same ocean that we've totally overfished? The same ocean that recently forced the fast food industry to change the fish type they use in their fish sandwiches, due to low yields on the earlier type? Oh, that ocean.
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DJTal
154 Comments
Re: Ocean fertilisation.
And how do you propose to restore the oceans to their former glory ? Sure , you could just wait around and let the oceans restore themselves, but it would take a very long time. What's wrong with putting nutrients back in the ocean ?
Reply
FathomsDeep
3 Comments
Re: Ocean fertilisation.
The oceans have to much fertilizing them already. Mass algae blooms caused by to many nutrients are creating dead zones all over the world and outside our backdoor. Farming something like seaweed/kelp in greater amounts is a good idea but most people won't eat the stuff.
Reply
yuanyijunc
3 Comments
Re: Ocean fertilisation.
the key to solar desalination is the cost, also need simple, the membrane, high temperature etc, is not affordable for solar desalination, we have developed a very simple core to realize the desalination and could work with temperature just above the ambient about 20 C, just a core, a fan and very little thermal energy, the core just plastic, two channels, one condensation and one evaporation, salty water evorating in the evaporation channels, and oure water condensation channels, condesation heat transferring supply energy for water evaporation, and little solar water are only for make up, very simple, very low cost, very little energy.
Please visit www.i-isaw.com
yuanyijun
Reply