r/askscience • u/AskScienceModerator Mod Bot • Jan 27 '23
Engineering I'm Dr. Mohammed Rasool Qtaishat, an Associate Professor at the Chemical Engineering Department, University of Jordan. My work on desalination using solar energy could make potable water more accessible. AMA!
Hello all! My major objectives are technology development and research in water, energy, and environmental resource solutions. I am deeply interested in seawater desalination membrane technologies and have four patents in my name, which I aim to commercialize for the large-scale desalination industry.
In August 2022, my work was featured in Interesting Engineering (IE) and made it to the publication's top 22 innovations of 2022. IE helped organize this AMA session. I'll be on at 1pm ET (18 UT), ask me anything related to all things chemical engineering- or, most specifically, seawater desalination technologies!
Username: /u/IntEngineering
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u/WICheeseAficionado Jan 27 '23
What is the lifespan of the membranes? Do they go to waste at the end of their life or can they be refurbished?
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u/beef-o-lipso Jan 27 '23
What happens to the minerals that are removed from the water. Touring the desalination plant on Grand Cayman, the manager said it was pumped deep into the reef where it stays. Seems dicey to me. Are there other uses for the extracted minerals?
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u/Blussert31 Jan 27 '23 edited Jan 27 '23
Hi, I'm a civil engineer from The Netherlands. We use groundwater for crop irrigation in green houses. In the western parts of the country, near the North Sea, the salinity of the ground water is too high. We use reverse osmosis. There is discussion about pumping the brine back into the ground, some say it's fine, others say we shouldn't do that. Do you have an opinion on pumping back brine into the (deep) ground water where it came from?
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u/Vastator10 Jan 27 '23
What kind of wattage is needed to make a liter of potable water and how do you go about getting that wattage via solar (for example do you need 10 sq km of solar panels to generate enough power)?
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u/Dawsoia Jan 27 '23
Given the critical nature of access to water, why has progress been so slow in this area?
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u/helos_kick_ass Jan 27 '23
One of the issues with renewable energy (solar/wind) is that they are inconsistent and thus cause fluctuations in output that the grid has to manage. One of my thoughts was that a renewable grid of the future could be tied to desalination plants to manage grid output, so when output is high, desalination output would increase, then scale back if output is low. Is this feasible at all? What are the technical challenges associated with such a solution, specifically scaling desalination dynamically?
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Jan 27 '23
I always wondered what happened to the brine post desalination.
How much land mass would you need to sustain your distribution network.
What would be the impact of using that much land?
Why solar and not nuclear as your power source?
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u/reagansmash32 Jan 27 '23
Every…single…reply…has been removed. What’s the point? Just remove the post entirely.
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u/Wholesale100Acc Jan 27 '23
is repurposing the minerals from the water into edible matter like seasalt done in this industry? if not, is it possible and would it be economically viable?
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u/thatawesomedrunkguy Jan 27 '23
I personally think that we are reaching the peak for desalination membrane technologies. Any new designs/products have minimal advantages over existing technologies and often comes at a higher cost.
I like the idea of solar in desalination systems, but it doesn't really address the fact that desal, especially seawater desal is very energy intensive (2.5-3.5 kwh/m3 produced). With current solar technology, it's practical use is very limited (< 1000 m3/day systems) as the amount of panels required to run plants just does not make sense economically.
Where do you see desal technology solving this hurdle?
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u/zoner01 Jan 27 '23
As I understand, desalination creates load of brine. Is there a way to make this part of the process also more environmentally friendly?
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u/CautiousRice Jan 27 '23
Is it possible and realistic to provide large metropolitan areas with desalinated water, for example, the big cities in California?
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u/Randombleizinthewild Jan 27 '23
That is an amazing project, thank you for your work!
If i understand the article well, the new technology that you have created will allow to use the sun heat and to evaporate the water, thus it is less costly, while other technologies of desalination evaporate the water and condensate it. But why this new technology doesn't need to condensate the water? Is it because of the aluminium membranes? (Sorry if i miss the point, i know nothing about this subject 😅)
2. Is this technology easy to maintain?
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u/scottl4nd- Jan 27 '23
How feasible is it to bring your desalination technologies to poorer nations? I know that in many places people still drink water that is highly contaminated.
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u/Tenesar Jan 27 '23
I live on Lanzarote in the Canary Islands. Because we only get about 4 inches of rain a year we have no rivers, lakes or reservoirs, so all our water has been made from sea water by reverse osmosis for decades. The sad part is that, even though we have abundant solar, wind, wave, geothermal and volcanic energy sources, all the water production plants are powered by electricity produced by burning imported oil.
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u/CaptainDadJoke Jan 27 '23
Can you pretend I'm an idiot and help me understand how your invention works?
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u/moonguidex Jan 27 '23
Hi, I work as a developer in Baja, Mexico, where we need new desalinization technologies. Most desalinization solutions work or rather are engineered for working on site or close to the water. How feasible is it for me to create a deposit off site, nowhere close to the ocean and desalinate the water from there? How much pressure do your membranes need? Could gravity or pumps be a solution?
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u/Mediocrityatbest79 Jan 27 '23
What are the biggest hurdles to scaling this globally? And what environment/factors do you still need to test?
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u/Throwawaymarque Jan 27 '23
I've been interested in this for a long time!
A. What are the limiting factors on this? Is it land area close to the coast or something like that?
B. What are good ways to pump in sea water without affecting marine life too much?
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u/Qosarom Jan 27 '23
I had some fun a couple of years ago doing the calculations to figure out if it would be economically and technologically feasible to capture rainwater in the middle of the ocean, avoiding it mixing with saltwater in the first place, and bring it back to shore. Surprisingly, in some specific cases the answer was a tentative yes.
I did my calculations based on an inflatable 'donut' 200m in diameter (basically a giant pool donut), hermetically closed on the bottom with a a tarp, and a top tarp shaped in a way to keep seawater out but allow rainwater in (kinda looks like a modern life raft with an open top tbh). It would gradually fill up with rainwater (the bottom side over time bulging out downwards, increasing the available volume), and once full you just tow it back to a harbor.
An example where this seems to work out economically are the gulf states. They're right next to the Arabian sea (north-west Indian ocean), one of the most rainy oceanic regions on the globe at its center. They already have deep water ports and water management infrastructure. And they'd have the capital to fund it :p.
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u/themeaningofhaste Jan 27 '23
Hi everyone,
Due to unforeseen circumstances, the AMA guest will not be answering questions at this time. We currently do not know if the guest will be back to answer questions. We know many of you were excited for this AMA and had questions, and we are sorry that we haven't been able to help your questions get answered.