How to Turn Sea Water Into Fresh Water Without Pollution | Earth Explained!

But there’s one problem – it’s in the middle of the desert. And cities require a lot of water.

Enter the Solar Dome, a new desalination system built on existing technology. It’s supposed to be a low-cost, efficient, and carbon-neutral way of turning saltwater into fresh water. With water scarcity already threatening the Middle East, Saudi Arabia is the world leader in desalination, but the process does pose problems. We take a closer look at the environmental costs of desalination, and how new innovation like the Solar Dome is trying to tackle these issues.

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Voice-Over: Julian Nightingall
Motion Graphics: Joerg Eisenprobst
Producer & Editor: Philip-Jaime Alcazar
Script Editor: Eleanor Updegraff
Sound Design: Hubert Weninger

A Terra Mater Factual Studios GmbH Production
#terramatters

Sources:

1 - Steve Jobs introduces the iPhone in 2007

2 - Svetlana V Boriskina et al.: Nanomaterials for the water-energy nexus. Massachusetts Institute of Technology (MiT), 2019.

3 - WIRED: "What’s inside this giant ‘solar dome’ coming to Saudi Arabia" July 2017

4 - Aondohemba Aende et al.: Seawater Desalination: A Review of Forward Osmosis Technique, Its Challenges, and Future Prospects. University of Leeds, 2020.

5 - Edward R Jones et al.: The state of desalination and brine production: A global outlook. Utrecht University, 2019.

6 - Ashraf Sadik Hassan et al.: PV and CSP solar technologies & desalination: economic analysis. Hamad Bin Khalifa University, Qatar Environment and Energy Research Institute, 2015.

8 - WIRED: "What’s inside this giant ‘solar dome’ coming to Saudi Arabia"
July 2017.

9 - Construction Week: NEOM inks deal to construct first 'solar dome' tech desalination plant. February 2020.

10 - Chris Sansom: Sun, Salt and Saudi Mega Cities. Featured News Article at Solar Water Plc. December 2020

[jaridkeen]

Why not just pump the brine into large pools and let the rest of the water evaporate and they can sell the salt.

[marjorietrahan]

I just did a project about desalination and we found another method called microbial desalination. It uses bacteria to exrtract the salt while generating electricity! Its amazing! There is supposed to be a pilot of this in spain if I remember corectly!

[VluggeJapie]

This is such an underrated channel. Please don't stop. I have shown multiple video's to my students in class. Some were fascinated and gave lectures about some subjects to their fellow students, I was so proud! Kids hold our future!!!

[jenr]

Being a retired working historian, I've had to do my share of reading about water, water rights, water wars, water sales, water shortages and the impending water crises. Your video was a grim reminder of an ever more critical future.

[gubjorgm.]

I really hope that this works and won't harm the sea more. If it works then this could help so many places.

[bruceallen]

Being a retired engineer, I would like to see these many water projects work across the globe since they offer a promise of solving more problems besides water. How do engineers get involved in such projects?

[seanstreck]

I wrote a paper about this in college during my undergrad in 2013. I actually think that the byproducts are worth more money Then the water itself. I did some pretty extensive napkin math and the one big problem with this process is that Is relatively large amounts of area are required to provide sufficient heat. The maximum reliable energy from the sun is about 400 watt/square meter. 20c sea water takes 4184 j/kg or 334720 joules just to warm 1L of water enough to vaporize at 100C. So to vaporize 1L of water per second, you would need 334720/400 = 29 meters square (a 100ft by 100ft bay of parabolic mirrors). A 1 mile by 1 mile field of mirrors would provide 2.56 million square meters of focused light or 3k L/Sec of vaporized water. That's about 100k L/hr or 1.2 million litres per 12 hours of sun. That's a nice number but then you realize people use 200L/day on average or more and you're not even at your 1 million people supported with an absolute gargantuan undertaking.

[toneyeye]

This concept makes a lot of sense to me, I always wondered why variations of it are not already in use. The brine can be fed to an artificial lake to evaporate and the salt deposits harvested for other uses.

[yggdrasil]

Egypt should flood the Qattara Depression. That would increase rainfall over the country and allow natural ecosystems to do the work of desalination for it.

[jjc]

water in holland comes from sea water that is pumped into dunes.
and inland, from rain water that is collected in nature reserves and lakes.

[MikSrf]

I literally thought if this as a child. Nice to see my ideas weren't just daydreams.

[edwardjennings]

And we still can't seem to realize how much we need each other

[totalrecall]

First time i see video about my country in English without involving politics
Thank you

[Zaihanisme]

I’m from Singapore and here we rely mostly on rainwater collected in about 11/12 reservoirs, with attached water treatment facilities, supplemented with raw water sold by our neighbour, the state of Johor in Malaysia, that is treated here and sold back to them at a discount. Together these make up 60% of the freshwater we get.
One third is being supplied with recycled water, branded as NEWater, that is basically highly-treated reclaimed wastewater. It’s mixed in with the above for general supply, or provided as hyper-clean water for specific industrial use. The remaining one-tenth is from desalination, utilising the reverse osmosis process.
The use of RO membranes in both reclaimed and desalinated water here was the result of extensive research to solve the issues of water scarcity for this tiny island city state.
I do worry about where the hypersaline brine goes, and even the byproducts of wastewater reclamation. There’s not much clarity about what is done with either here.
A project like the solar dome wouldn’t be quite possible here due to the lack of space, though it could be setup on one of our smaller islands, but obviously on smaller scales.
The best solution would still be to improve our urbanscape to greatly increase the water catchment area, and hold water in the environment for longer, thus prolonging the journey of water to the reservoirs, and reduce losses via evaporation. With an average annual rainfall of 2400 mm, we’re not short of water gifted by the skies above, just need to be better at catching, storing and more mindfully using all of it, so we don’t need expensive and problematic technologies, or an occasionally petty neighbour, to depend on.
Perhaps you can do a video on water catchment methodologies that more urban areas should adopt?

[Greenskies]

My water comes from the local pub but is contaminated with yeast and fermented grain 😅

[ashanarchy]

I came up with this idea when I was 10. On a much smaller scale. After going to a science show about parabolic mirrors. I showed it to my teachers and parents and they just rolled their eyes. I live in Scotland, they were all thinking its too cold here for mirrors to evaporate water.

[bonefetcherbrimley]

I hope this method of turning sea water into fresh water works. After the debacle that was those big ass artificial islands in Dubai, I am a bit skeptical. But here's hoping, it'd certainly be pretty neat!

[fer]

Economic problem 2:19 - Byproduct 2:49 - Saudi Arabia and desalination plants 4:19 - Solar dome 6:08 - Brine 7:03

[michaelcarey]

I also had this idea on a more simple scale. Shallow black pond with greenhouse plastic over it. Water piped up in black tubing heated by the sun/sand. Also a few steps beyond this desalination plant. Build a community center at each desalination plant for people to come fetch fresh water. Composting toilets are built here. Humanure is then used as a medium to plant jatropha plants. Jatropha is a berry shrub that grows well in droughts and desert conditions. Its berries contain 70% oil. The locals are encouraged to pick the jatropha berries where they can exchange them at the community center for staples. An on-site low tech processing center (think stepping on grapes for wine) presses oil and packages it for sale as a global commodity to be used as biodiesel/ jatropha oil. This is a low tech and low cost plan for helping to reverse desertification in Africa (or similar barren lands with ample heat and salt water).

[benthere]

Thermal desalination can be extraordinarily inexpensive if it is done with molten salt reactors. Molten salt reactors operate at temperatures high enough to generate both electricity and desalinated water in the same system. If the molten salt reactor is fueled with thorium the nuclear waste is only dangerous for less than 500 years.