Why Is Desalination So Difficult?
An overview of seawater desalination: removing salt to make drinkable water from the ocean.
Correction: The Carlsbad plant produces 50 MGD, which is roughly 190,000 cubic meters per day (not 23,000 as stated).
It might surprise you to learn that there are more than 18,000 desalination plants operating across the globe. But, those plants provide less than a percent of global water needs even though they consume a quarter of all the energy used by the water industry. The oceans are a nearly unlimited resource of water with this seemingly trivial caveat, which is that the water is just a little bit salty. It’s totally understandable to wonder why that little bit of salt is such an enormous obstacle.
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bruh literally never quote the WHO or WEF ever again.
I don't understand why a flash evaporator would reduce scale build up. Probably because I can't visualize it; do you know of an image or paper I could read to clear up this idea? Thanks for all you contribute, Grady. I love it.
The brine is also a potential source for rare minerals, etc.
why can't the desalination plants harvest the waste brine for salt? selling real sea salt would be a good way to make up some of the cost.
Oh yeah, private water companies have such a fantastic track record. That will definitely save costs in the long run. Yep. Please, do come and visit the UK; boat in our pristine waterways and relax on our totally not sewage covered beaches. All this in return for the £54bn in debt which they have totally assumed responsibility for and definitely won't have to be picked up by the taxpayer. /s
I've drank literally thousands of gallons of desalinated water over 20 years while I was in the US Navy. First ship used 7 stage evaporators and the last two used reverse osmosis. You couldn't tell the difference between them since it was pure water that came out of them and the engineers added minerals back into them to make them drinkable.
How does the engine add the minerals back?
Ship scale is a lot easier than city scale, glad it works
@@johnmicheal3547 Its not an engine. Its a desalinization plant. The chemicals are put in the water using a metering device before the water goes into the storage tank on the ship. We only had bromine injection on our ship. Bromine is used to kill any bacteria in the water.
Same here. The water got interesting on one of the big decks I was deployed on when it tried to distill saltwater fouled by fuel dumped by a Harrier. The "drinking" water tasted and stank of JP5 for weeks.
On our ship(USS Camden) we were fine with just a 5 stage evap. One was in the forward MMR and one back aft. The one back aft always made more water as my evap had a vacumn leak somewhere in the aux exhaust preheater that I could never find(but made a great shower during shutdown when the vacuum was broken lol) Sounds like you were on a carrier lol.
I'm a Navy veteran and I served on a Nuclear Aircraft Carrier. We had a desalination system built into the Reactor system using the excess heat from the steam powerd turbines. It was actually very efficient.
Nobody cares, bud.
nice, i was wondering exactly this. as nuclear and other powerplants have to boil water anyways, why aren't those systems combined?!
@adrieltc sadly nuclear doesn't have large profit margins. So big energy used the fear of radiation and meltdowns to justify closing plants... then went back to fossil fuels.
@@andybaldman I care.
@@adrieltc They are combined at times, but the designs have to be tested thoroughly.
As a water treatment specialist it feels good to be seen. The RO segment was dead on. TDS and scaling are constant challenges.
Same here, this is some great stuff, eapecially when family and friends ask me why don't we just constantly clean sea water 😂
@@WalterOMSD Because it is energy prohibitive... and that is the only actual reason. Most of the "issues" here are because they are trying to make it economically viable not because it is super difficult.
Don't worry, we see you. No need to ever get salty ; )
@@thomgizzizexactly…it’s not difficult at all…it’s just not economically viable
Thanks. My country relies on people like you for about 1/4th of is water supply
I grow salicornia (sea asperagas) at home and it does surprisingly well turning salt water into usable water and a snack thats pretty dang salty and not bad tasting in my opinion. Not sure if its great for every purpose but here in florida it works pretty well.
interesting!!!
Can you use sea water for cooking vegetables?
freezing water as in sea ice will also desalinate the water.
@@kitemanmusic besides the salt there's also pollution, especially if you get it at a beach near a city. And it tends to be too salty for taste
Very interesting, how much do you harvest?
It is SO extremely important how you put things in perspective in these videos. “It took X kilowatt-hours to do this process.” You could end there and compare numbers at the end, but then people wouldn’t understand what that actually means. It’s great.
And then it ends on --> 800$ PER DAY electric bill for utmost emotional damage.
@@Rncko Honestly, it was better than I was expecting... Although _all_ the caviats were (more or less expected) bummers.
And then he dissed Nuclear... Which makes his points all moot. If you diss Nuclear, you don't deserve to have electricity in the first place. And that's probably why he lives in the eternally worsening state of California. Which only has 1 Nuclear Power Plant left, and constant power outages because oh look at that, these brainlets think Wind and Solar are good sources of energy... Let me tell you this, You'd require to cover the Entirety of the USA in Solar Panels to cover the global energy usage per day on Earth. You'd only need 2000 Nuclear Power Plants. And when they succeed with Fusion Plants, that number would drop down to 20.
The sun does this for free by the millions of gallons a day. No “x watts needed” It’s not the process, it’s the method. The process is natural.
@@Rncko yeah, it's weird that that point was made against evaporators, while the ~$7/mo of industrial membrane plants wasn't expressed. that is only the primary desal step though, but even if we were to posit that all the rest of the costs increase the price by 5-10x (which would be completely ludicrous) it's still just $35-70 per month. not great, but not exactly catastrophic.
Here in Uruguay we are facing a drought right now, and the government decided to mix treated salt water in the normal fresh water supply, so now we are getting water on our taps with a salt concentration about 10x of what it used to be. This video turned out to be very well timed for us.
so the water wasn't treated that well?
Si pa?
@@alexalekos no, they're literally running out of fresh water so they're using treated salt water to pad out their remaining supply to meet demand until sufficient rainfall. read.
@@s_t_r_a_y_e_d but 10x the concentration is more than the intended for desalinated water
@@alexalekos The water is well treated but they're purposefully blended with high salt water to increase the supply. Bad treatment would mean accidental dumping of salt water, no removal of toxic chemicals or bacteria, etc.
Love this channel. As a trained EE I wish my education had this kind of practical experiments and thought-experiments.
Really great explanations and comparisons. Thank you for taking the effort to set up the bench top examples. I believe that desalination won't come into popular view until it is the only choice left for larger regions of the world outside of the middle east. As mentioned, water is plentiful but the amount of energy it takes to transport it and prepare it is key.
To quote the Ancient Mariner: 'Water water everywhere, but not a drop to drink.'
Why not use solar and wind power as part of the energy solution?
I think one reason people may have a hard time wrapping their head around how difficult it is to get the salt out of the water is that they can’t see what it does - it’s not just swirling around in there, it’s dissolved - it’s harder than getting the cream back out of your coffee
Next time observing a mountain creek, let's admire the exquisite amounts of energy provided by the Sun to distill all that water.
Now If only Texas would fix their broken infrastructure that is losing billions of gallons.
@@LiborTinka *low entropy energy
@@AlexanderNashYour comment only serves to show off. Shame
@@LiborTinka yes the suns energy runs the planet. we are still highly dependent on fossil fuels - which are depositories of the suns energy from millions of years ago. by the way, the energy to charge batteries comes from fossil fuels so don't drink the Kool-aid
Spoken like a true engineer... "The instructions didn't say to not run salt water through the pump"
Yes. This is another engineer's problem. He is actually helping that engineer discover failure conditions to add to the warning labels.
They will do after this video
That's good. If the pump gets broken in the process he can return it since he didn't use in a way it's not supposed to be used.
@@seneca983: True but the pump guts are ceramic, stainless steel and silicone rubber so clean salt water should not hurt it. 600 psi is under half it's water blaster pressure so should not be strained either.
@@howardsimpson489 If it's stainless steel it would probably corrode somewhat faster than otherwise. Stainless steel isn't really completely stainless. Though maybe it's not a big issue.
Thanks for covering the renewable energy part, I've been grumbling about using that for years. Now I have a clue of the continuing drawbacks.
You are a gifted presenter. I engineer stuff all day but get almost giddy sometimes when you release a new story.
Here in Tampa they tried to build a RO desal plant near the Apollo Beach Power Plant. The biggest issue was not any of what you outlined here. The problem was zebra mussels. They are a non native invasive species that would collect on the intake pipes for the desal plant and they were spending 100's of thousands of dollars each month just to keep the pipes clean, and that is what killed the project in the long run.
Imagine living in Florida out of all places
Not sure why one of the wettest states in the US needed a desal plant anyway. There's no way they would make any money when their competitors would just be collecting and treating the readily available freshwater for basically free by comparison.
@@cowabunga2597considering the amount of people who move down here, I don't think your opinion is the popular one
@@thisutuber You could but that doesn't mean you'd have made any money from it, lime isn't exactly in short supply.
This is exactly the kind of unforeseen challenges that he was talking about. For new technology you often have no idea what issues might show up along the way.
Lived in Saudi Arabia for a while and dad worked at the desalination plant there. Interesting bit was steam generated by the boilers were split into two pressure points. High pressure steam was used to turn the turbines to produce electricity while low pressure steam was used to make fresh water. Interesting when I heard about it the first time.
That’s what I was wondering why should it “cost” energy to generate steam. Isn’t basically all of our energy added to the grid by steam spinning a turbine? Surely theres some way to spin a turbine and then drink that same condensed water vapor right?
And water cost more than their fossil products!
@@jakeannett6720That's distillation, purify the water of germs and removing salt content but it is the costly method of desalination.
I wonder if they ever thought to use this concept but with a nuclear power plant
@@jakeannett6720 This is a great thought, but sadly there are some big drawbacks. The water used in most power plants is highly purified and the same water is used over and over again (closed loop) Using sea water would lead to more corrosion and mineral buildup in the pipes and mechanisms of the powerplant. It might also wear down the blades of the turbine.
One issue missed by most people who promote desalination for urban use is that the sea water near the coast is too polluted to desalinate and drink. The ship I worked on required us to be 25 miles offshore to make potable water.
Salt flats were once massive brine pools. RO and pumping the brine onto large desert lake beds adds to the evap cycle. Salt deposits can be broken up and stored away. Also thinking about MITs recent answer to desalination which uses ion concentration polarization omitting the need for pumps or filters and can run off a $50 solar panel, it's less than 22 lbs, simple to operate and about the size of a small suitcase.
On our 470' research vessel housed 130 people, we had two distillers plus a reverse osmosis. The distillery was pretty brilliant as we pulled a vacuum on the container and we used heat from our diesel electric engines. When the vacuum was applied the water would vaporize at 165°F rather than 212° F pretty clever. The units on our ship produced 1200 gallons per day. Some of that water was additional purified by R.O. So the waste heat from the engines was not an additional cost only the energy used by the pumps was energy negligible.
That's super interesting! Do you think the energy required to place the vacuum in the container cost a notable amount of energy or was it negligible?
It was really clever to drop the pressure below atmospheric in the container. Thus reducing the boiling point of the water🤔 did you just use the already existing vacuum to vent the gas out of the container. Or did you have to use a constant vacuum pump for that?
I can only assume pumps would be needed. But if the baseline vacuum pressure; the bulk work is established using venturi pumps/valves, then you can certainly leech that from a multitude of engine and auxillliary systems. Basically anything with a suitable fluid flow range can be exploited using venturi effect to generate vacuum without a notable energy or efficiency loss to those systems - because venturi is sort of a "skin drag" effect; it doesn't require any direct interference with or impedence of the fluid flow itself. You certainly _can_ bottleneck a flow to accellerate it and boost the vacuum pull of the venturi effect, but with large flow systems already in place and available then mass can go a long way in making up for speed. On a ship, engine inlet air, engine exhaust and coolant flows are probably the most interesting ones. Especially exhaust as its alrady waste energy, fairly high flow, and most venturi applications wouldn't really have much impact on the ability to use the same exhaust gases for _thermal_ energy. Then vaccum pumps might only be needed for moderste boosting, or as an inline support system to ensure adequate "vacuum pressure" stability.
@@jippo91I remember working on a similar one at a company I used to work for. It has to be a constant vacuum. The issue is that with the little heat needed (compared to standard boiling point). The water's evaporation aka expansion reduced the vacuum in the chamber. So we had a pump to maintain a constant vacuum. Here's the cool thing. The pump was a mechanical vacuum pump that was also ran by the motors fan belt.
I live in Malta. Most of our water is desalination water. Pure water without added minerals will eat and absorb almost anything. I worked at well known soft drink bottles and our water filtration room looked like a water fountain. It was made of solid stainless steel. Amazing what water can do .
Desalination plants combined with gen 4 nuclear power plants equals cheap carbon free electricity and as much water as the world needs. Unfortunately governments would rather control us with blackmail and fear.
Yes - deionized water will alter taste in your mouth just by sucking in all the minerals. Naturally there should be a little sodium, calcium, magnesium, chloride, sulfate etc. in the water for it to taste fine.
Also called Universal Solvent. Great stuff.
@@20chocsaday Also hydroxic acid.
That's exactly why the pipes in nuclear powerplants have to be high-quality stainless steel. The reactors have to have 100% pure water. Otherwise, you end up with a ludicrous amount of buildup in the cooling pipes, which is.....less than optimal.
Really good explanation of it all! I’m an operator at a large ultrafiltration membrane plant not far from the Carlsbad plant. Membrane technology is definitely our future and we are going to see more sea water RO plants popping up as our population grows in the U.S.
Or we just use nuclear power, completely removing power draw concerns.
The problem though isn't technical, it's political. Most people who live in cities are working class so capitalists are not going to build a desalination plant. Just like with electricity in the 19th century the government will have to step up and make massive investments in hundreds of giant desalination plants and set up huge agencies to operate them. The problem is that most western governments have become incredibly timid about huge projects like this and just like railways desalination is a very all-or-nothing thing. You have to commit to it or it will be a total failure.
@@MrMarinus18 wat? None of what you posted here makes *any* sense. Most cities literally can't *have* a desalination plant because *they aren't near the ocean*.
@@vyor8837 Nuclear power is one of the most expensive power sources. It would make much more sense to use solar power, especially since drought conditions usually come with a lot of sunshine.
@@SerienchiIIer It's only expensive because of regulations that exist specifically to make it expensive.
I recall reading about a mechanical technique for desalination a while back. (I think it was an israeli paper?) The idea was to lift a column of water in a sealed tube as high as possible until the weight of the column overcomes the air pressure and the water stops rising, forming a vacuum on top. the vacuum fills with vapor which is then forced out through a one way valve as the column compresses and the falling column which is still mostly liquid water can be used as a counterweight to raise another column. With multiple columns you can create a desalination engine. I'm not sure how this method compare to the membrane approach, but it would be interesting to see.
If there is one thing we can take away from the last 50-100 years of US and Global corporatism its that private industry only makes things cheaper in the very short term, abolishment or at least reining in of corporate lobbying power is a necessity when discussing the use private industry to "reduce cost" of public utilities. Even suggesting that as someone who is living through the global crisis change or even more locally to your life, the US's private energy sector's reluctance to even consider renewable until the profitability breaks 3x, Texas's privately owned and run power grid really shows how bad of an idea it is to rely on private corporations for what really does require country sized coordination. A private utility selling water back to citizens will always be a worse long term solution to robust government infrastructure
I worked in a power plamt that used a multistage RO to clean up produced water from an oilfield. The oil was separated, and the water was run through softeners, but it was still in the part per thousand range. We ran the RO at 75% permeate and 25% reject in the winter. We had to run it at only 70% permeate in the summer due to the water being much hotter. Input temperature and pressure have a high effect on the process. We got
What did you use the DI water for?
@@sealpiercing8476 DI water was used for injection into a GE frame 6 gas turbine for NOx control. Some of the RO water was used in the engine inlet evap coolers to increase air density and improve power output (more air, more fuel). One plant that my company operated started with well water. The sequence was sand filter, carbon filter, softener, another carbon filter, RO, deionization. At each stage some of the water got sent to the next stage and some got used in a process such as the majority of the soft water being used as makup water for the boiler. All effluent streams (incuding rainwater) ended up in a flock tank and then a press. No water was allowed to leave the plant except as vapor from the inlet coolers and the cooling tower. Even black water was run through a mini sewage digester plant. The water that came off the press went back into the cooling tower. The solid “cake” that came off the press was chemically and mechanically identical to limestone, but was still classified as hazardous waste and had to be disposed of accordingly. We bagged it, and shipped it to a facility that stored it. The facility was, appropriately enough, an abandoned limestone quarry. That was the only zero discharge plant I have ever seen. Even then, the government wanted to dispute that classification since the bagged limestone left the plant. There was a tax break involved for being a zero discharge demonstration plant. Our lawyers pointed out that under their criteria it was impossible to have a zero discharge plant because some evaporation is required in any power plant. In the end, both sides decided to nullify any contracts and abandon the project. As far as I know, the plant is still rusting away, and nobody is attempting that kind of usage efficiency today because when they look at doing it that plant is held up as an example of a failure, even though it really succeeded. All because a government bureaucrat wanted to avoid giving a tax break.
@@sealpiercing8476 what do you NOT use DI water for? it causes far less corrosion and leaves next to no scale/fouling
@@Simple_But_Expensivewow, that's a really good story. are you still in the business?
The theoretical limit of water purity is 18.2 Mohm. In the semiconductor industry we meet a water purity requirement of 18 Mohm continually.
love your accuracy and engineering approach of explaining things: make complex things simple!
love that you did an experiment demo and didnt just talk about it. the scientist in me loved it.
Well thank you Grady! My late father was a widely-acclaimed reverse osmosis water chemist but I never understood exactly what was special about RO, and the difference it could make. He travelled extensively in the UK and the Middle East, solving RO problems encountered by water utilities at local and even national levels, eg Namibia in Southern Africa. This video has resolved for me what had been a fog of comprehension, so I can’t thank you enough for facilitating a new enlightenment for me! 🙌 High five to you Grady!
@@realityveil6151neeeeahha neeeah neeeeeahaahahhahaaahha neeehh? neeeahahah neeeeh? Neeeh!!!
@@realityveil6151 Of course I did but I never completely understood. A combination of youthfulness and the way it would have been explained by a technical expert.
@@realityveil6151 This dialogue is at an end.
@@realityveil6151 You are an incredibly sad individual
@@realityveil6151what did you gain from annoying random strangers
Can I say I find something profound in this channel. There is so much mystery to our day to day but we are too busy to notice. When you read between the lines, this channel not only streamlines education, but also helps us understand why our modern society is built the way it is and makes us analyze and criticize. Keep it up!
it ALso MAKES deSALinAtion exCITing...BUT I'm NOT exACTly SURE how he DOES it!...
Just saw a vid about cheating in research in order to be published. Hmmm ... I tried to find it but can't. Lots of other sources on same thing though. Google: Harvard gina cheat
"too busy to notice". Wow. that is such a sad state of affairs. "Too busy noticing" Would be better, and it IS a choice. ...and hey, you're here! You are noticing.
I lived in the desert for 25 years. In that period I build very simple solar distillers that delivered less than 1 mg/l total dissolved solids. The feed for my stills were about 2500 TDS. All the water I drank at my home (that really is almost all) came from these stills. There were a few technical improvements in building them but it is possible to produce drinking water (and even water for laboratory use). The problem is that people need to use saline water for a number of purposes rather than purified water because solar distillation gives really pure water but great enough in quantity not in fire fighting or irrigation. When I see this, I realize how primitive our society's understanding of water chemistry is.
Before I had to move and downsize, I kept a few large marine aquariums. It's funny how the process of making seawater out of tap water, and making tap water out of seawater both have RO filtering as a middle step. Though for making seawater additional deionizing resin media is also necessary.
Brine water is used a lot in Europe for closed vertical ground source heating or heat pumps. Brine water is a useful resource to transport heat energy without the risk of the medium freezing.
I never knew that could even be done! Thanks for sharing!
Interesting! Makes sense.
That's cool. The game I play a lot call oxygen not included has brine and salt water that is mainly used for coolant because it doesn't freeze. I didn't realize that that's a real thing. Just thought It was game balance.
@@dr.chimpanz.1324 ONI does have a good bit of sci-fantasy elements (the funny reverse entropy device for example), but almost all of the physics in that game are based on reality, if a bit exaggerated and simplified.
@@fauxfirefurLllLlLall(
One thing he forgot to mention is that reverse osmos is extremely reliable. Let me explain, I'm from Ukraine, and more than 20 years ago, my father bought a 20 liter per day plant for $100 (from the US by the way). And you know what? We have not changed the osmosis even once in all the time, only every 2-3 years the primary filters. And the quality of the water hasn't changed. It's really amazing technology and now it's also cheap.
Hi, I'm wondering whether u or anyone u know who understands the desalination process would consider it at all possible or practical to share this process with other engineers located in Gaza. It's a big stretch but surely there would b people there who could benefit and use that knowledge in some way as drinking water is so scarce. Or even turning fetid water 💧 into drinking water using tablets. Just trying to offer some solution to their current situation which appears dire. And BTW, I pray for ukraine and its liberation from Russia everyday.
It might be good to have private companies build these plants but it drives prices up and relies on a third party. While I agree private versions would be good I think essential utilities like water should always be government powned.
I work in water treatment in my county as an operator. We adopted membrane filters in the mid 2000's and there are very few treatment plants (at least in Canada) with this newer technology. Our membranes are made by PALL. It's such a new technology that the lifespan of the membranes is still unknown (outside of salt water). We have ordered a complete new set of membranes that will be replacing the old ones next year but this is only cautionary and not reactive. Our tmp's (trans membrane pressures) have held up with only minor, routine maintenance. Our effluent remains well within the 0.1 micron spec and our turbidity exceeds our provincial standard by multitudes.
What's interesting is this is the exact opposite of making maple syrup. Both distillation and reverse osmosis are options available to producers. But, in the distillation process, they keep what's leftover in the pan after most of the water has boiled off. And in reverse osmosis, they keep the discharge and reject the fresh water.
Possibly sell the waste water from the sirup process as sweet water, naturally flavored.
@@world_still_spins You can sell the unboiled sap for more. It's eminently drinkable right out of the tree, and the trace minerals are believed to have health benefits. Also, if it's still sweet after RO then you're doing it wrong.
So your saying we can solve the water crisis with mass scale maple syrup production
@@oceanceaser44 May not be impossible. There's new tech now that coppices maples, then applies a vacuum pump to the saplings/shoots to extract the sap. Still very new, but apparently very efficient for sap production. If you can get the tree to grow, then it can produce a lot of sap from sub-optimal water sources. The caveat is that it's only in certain climates, and only in the spring.
@@bobcostas9716 yeah, but this syrup is imported wildly to Europe and it is disgusting, very poor quality compared to 'classic' syrups. I am not sure if this is caused by the tech or that they just settle on lower grade syrup.
Yes, I'm that guy. "How hard could it be?" Thank you for explaining how hard it can be and the energy costs involved.
A big chunk of the energy costs are from chemistry/physics constants like the heat of vaporization of water. If you want water to change from a liquid to a gas that will be 2.2kJ per gram. This is part of why reverse osmosis is more efficient, it doesn't involve boiling the water but will instead have other costs. (Like the energy input to pressurize the water, pressure can be considered a form of potential energy.)
I really love the information you put out here. The only point I disagree is the privatisation of water treatment. Companys and investors deciding prices for drinking water after contracts have run out. There have to be other ways for water desalination or use of water rights.
Exactly. Privately-owned public utilities is a much greater evil that he realizes. But he is extremely didactic when it comes to explaining engineering & chemical situations so I shall continue to subscribe. And that (misguided) statement was a very small part of an otherwise tremendous video.
It's pretty frustrating. How does the private company compensate for the risk? Why, by charging more than it would ever cost! Governments are big enough to compensate for that themselves, *without* also needing to compensate boards and shareholders.
@hairymcnipples no they can't. Governments cannot effectively allocate resourcesb
@@hairymcnipples the problem isn't risk but lack of competition. It's usually hard to have multiple infrastructure providers in a location in a reasonable way
I have a small wall mounted ultra pure water distiller that uses a flash evaporator in the sense it throws spirts of water on a hot plate. It makes 5 gallons per day and draws less than 10 amps 120v. Pretty neat but super expensive.
During the "Millenium Drought" in Australia the NSW government funded an RO desalination plant to supply 15% of Sydney's drinking water with provisions built so it can be easily scaled to supply up to 30%. It's energy needs were offset with a massive new windfarm just out of Canberra. The plant was finished in 2010 right as the drought broke, so it was mothballed and wasn't used until the 2019 drought
There's a heap running in the other states except for Tas. And of course Toukley planned but deferred back in 2007 in our case. We really do need to reconsider them in NSW since Sydney's water demands can cause difficulties for other catchments, and also to support some of our ag needs rather than impact the regional water supplies.
Perth gets about 50% of their drinking water from our desal plants
@@kevinrudd1 not just Perth, you send a lot of water inland via pipeline.
So das the desalination basicly work energy storage for the windfarm?
I was in the Royal Navy as an engineer and worked extensively on desalination and distillation equipment. After leaving I travelled as a civilian desalination engineer....brings back memories..
Today, global sailors (boats of 30 to 60 ft or so) mostly have a desalinater on them. These sailboats have good solar power and storage on board so they can power the desalinator. The sailors also learn to conserve both electric power and water. Find numerous YT vids about installing and using such systems.
There is a third desalination method that is used. Electrical desalination. The technology takes advantage of dissolved salts charged nature by running an electric current through the water and across ion seperation membranes. The negatively charged chloride ions are attracted to the cathode, and the positively charged sodium ions are attracked to the annode. The set up is only slightly more expensive than a thermal set up to install and it is an amazing demonstration of physics and Maxwell's Equations in action.
One issue with privatizing the production of drinkable water is that it gives private companies a lot power over what's essential to live. They could, on a whim, raise their prices and the state (ultimately, the people) would have no choice but to pay. And there wouldn't be much we could do about it. Private companies have profit in mind instead of public service. Which should be the core goal of utilities.
Question: How is that any different from a government being in complete control over the water supply?
@@rosskwolfe The question should rather be: how is that in any way similar to the government being completely in control? A State is not a company, and should at no point be run like one. (Looking at you Macron.) Basically, a State making money is failing at being a State. Whatever money it makes could (and should) be reinvested into public services. But even worse than that, a State making money actually fail at enabling the creation and sustainment of companies. The whole point of a State is to enable fairness on many topics. To provide for the unlucky few by taking from everyone. To prevent a lucky minority to gain too much power and control. At no point in time is profitability even a question. So yeah, I'm asking again: what would be similar?
@@rosskwolfe Because it's a captive market which is prone to abuse, the market corrections are not available but with government run the corrective mechanisms are still present. It cuts out a layer of profit making operating costs lower. The government generally has to pick up the bill if it fails anyway whereas shareholders are never held to account for running the company into the ground and skimping on maintenance while walking off with the dividends (looking at you UK privatised water companies).
@@rosskwolfe The government wants people to live and you have a say in the government. Don't ask questions like these anymore.
True but if the problem is huge enough, government could essentially regulate it and the company have no choice but to comply. They of course go out of business if the regulations made it unprofitable. In the end the technology will be developed as long as there are incentives, whether it's profit or public needs.
The potential for a problem with outsourcing to the private sector, is one that seems to be happening right now in the power sector in my part of Australia. Our energy sector was privatized in the 90's, and since then, the problems with the plants have increased over time, plant maintenance, and regulatory requirements often getting overlooked in favor of maximizing profit margins. Now, the plant owner, after years of neglecting the equipment, when faced with a generator that needed replacing, instead decided to shut down the power station, and simply walk away, now, the remaining 2 stations that service the majority of the state, also have closure dates before the end of the decade, with no talk of replacements other then unreliable renewable's such as wind and solar, which currently make up 21% of the market (except during the summer months when diesel generators are used to offset the demand) These are some of the reasons that for anything utility related, I personally support state or city owned assets, especially for power, water, and communications.
Same ol' story. The "unnecessary" costs that get cut by the private sector are long-term vision (designing for the future; maintaining existing equipment so it lasts beyond short-term profit windows; etc), safety, and living wages. Basically the kinds of things you want for your children and your children's children if you're a decent human.
This is exactly what I thought would happen, and it is why I was kinda shocked when the video said that it was a good idea to let the private sector take the risk. We are talking about a resource essential for life, the risk will eventually and ultimately reach the population.
@@annamyob4624 The other flow on effect since the sector was privatised, and I can only go by talking to people taht have been in this region lot longer than I have, but they say that we've lost SO much in terms of skilled workers and knowledge. Some of the equipment was essentially scrapped, because there was no one left that knew how it worked, or how to repair it. You hear the same storys all over the globe when this kind of thing happens, and profit becomes more impportant than the service it provides.
Example nr; 124634588862623 of Capitalism being awful
@@kristoffer3000but I MUST CONSUME
This is really high quality, highly informative and professionally narrated content. Hats off to you kind sir, for summarization such a complex subject while still keeping an objective stance on the matter. Really, really well done.
⭐
I'm working for a company in the Netherlands that builds and uses machines for ground water (a well) and de-irons it for farmers or who ever needs it, also building ro and ion changers for all sort of uses from farmers to sauna's. Verry interesting stuff, got a cliënt who gets salt (brak) water from his well and uses 3000 liters for 1000 clean water using a RO. It's quite efficiënt for how bad the water is before but it's a real big energy user because the RO works at 10 bars so the pumps really work hard
After major draughts around 2007 in South East Queensland a desalination plant was added, but it was only part of the solution. All of the major dams across the region were connected via pipelines to help balance water supplies. Water can be pumped between areas of the region and the desal plant is used only when water is needed and can also be used as a buffer load on the power network too from what I understand
One of the most interesting things you can see is where a fresh water river flows into the sea. From overhead, you can literally see the boundary between these two different sources of water as they mix. It is worth noting that the conditions in sea water intake vary day by day and even during the day. So conditions in a desalination plant have to be monitored closely in order to ensure efficient operation and a good product at the outlet.
I think such a boundary is called a halocline, iirc
In some places, they have plants that win energy from this mixing, sometimes called "blue energy". This clearly shows it takes energy to get the salt out.
ok
I just discovered this channel and I have to say that I'm loving it, everything is really interesting
Thank you for this explanation of the difficulties of desalination. I found this helpful.
I've always been interested in learning how desalination works, I'm glad you've finally done a video on it!
I remember reading about some Rice University research where they added nano copper particles (which are very black/dark colored) to water and exposed it to sunlight, and the water rapidly heated. But in salty solution, maybe the copper particles might bond with the chloride? Well, if not, you could combine the above, with also decreasing pressure on the system to lower the boiling/evap temp of the water. Then, the containers you use, could be borosilicate glass that have double wall, vacuum insulation. The combo of all 3, would very effectively use Solar energy to convert the water into its gaseous state. Granted, making such large glass containers with double wall, would be difficult in and of itself. But they wouldn't need to be too large though. Because between the lower pressure, the direct heating copper particles, the high degree of insulation, you would very rapidly convert the water into water vapor. The main issue would be dealing with the salt and keeping the nano copper particles separate. There is an alternative to the above, which is probably less efficient, but if you're using solar, won't matter too much and there is no particles to recover. Inner metal tank that is painted with ultra, ultra black, and then with borosilicate glass outer and again, a vacuum pulled on the space between the two containers (and again, also in the containers themselves to lower boiling temp). On particularly cloudy days, at night, of course you would have to use some other heating like electric. But, using the Solar would drastically reduce costs overall.
The reverse of reverse osmosis can be used to generate power. Osmotic pressure can be used to drive turbines. In fact, you can use salt as a sort of energy source that way, mixing it with seawater. So, if you have a really concentrated brine after your RO desalination, directing it to an evaporation pond where it turns into salt which can be used for power production when mixed with seawater is a kind of weird way to recover some of the energy you used for desalination (plus solar thermal energy).
That was fascinating. I got to research this now….
@@oldmanspooky6641 no because it is a really dumb idea
An idea I've long wondered about in areas where seaside land is fairly cheap, such as the Middle East: seawater canals with an arched greenhouse over the top with collection gutters on the sides. Water from the canal evaporates, condenses on the greenhouse, and runs into the collection troughs. I'm sure this would be more complicated in practice, but it seems like a good way to use solar energy in a passive manner.
that's the best idea in the comment section (I'm a scientist in this field)
Dang that's pretty smart and simple
water like that would start growing organisms
@@techheck3358 So? They can be filtered out easily. The hard part is removing the salt, which this does.
Armchair science time. This could run into issues with creating flow. There are no rivers flowing through Dubai (other than a creek with the sea on both ends), according to a cursory check of Google Maps. So you’d need to induce flow to prevent salt and organism buildup. Flow could also reduce the efficiency because the new water would need to heat up. Also, the space vs. output might be an issue for certain areas, although if you live in a desert there’s probably a lot of available space. I’d bet you could get more out of a solution like this with a bunch of (pretty cheap) mirrors too. Cool idea
Grateful for all that you do with this channel. As a non-engineer, this is an incredibly helpful way to grow my knowledge.
yes!
I was stationed on a modern Aircraft Carrier. Heat is not in short supply when you have a couple of reactors, nor is electricity. We distilled all of our potable water, and then it must have been re hardened to some degree, because it was easy to rinse soap off in the shower. It also tasted really good if I remember correctly. It has been about 30 years.
Also, we made much more potable water than was required for air crew, and ships company, about 6000 people in total.
Hello. Thank you for the great lesson on desalination. It was better than what I learned in my thermodynamics class.
I ran evaporators in the Navy and drank the water for many years, it was pure enough to run through the boilers without building up excess scale as well. Tasted great, and made a mean cup of coffee.
So?
@@whosjulez1157they were commenting on their experience with desalinated water. It pertains to the subject.
Would be interesting to cover desalination in nature. For example, plants, animals and fish which can filter out salt from water...
do they? i thought it was primarily rain that provides desalinated water
@@kmanccrseagulls can drink salt water cuz they have these salt glands that lets them cry out excess salt. I personally think that’s freaking dope. If we had that we wouldn’t have a water crisis
@@kmanccrso you think ocean fish drink fresh rain water?
@@codycast No but the salt isnt removed from the ocean... ie they aren't desalinating the ocean are they? they put the salt back into the water. I guess what op is getting at is how their kidneys regulate salt and remove it from their blood and to replicate that process at scale.
@@codycastDo fish drink at all? Can it be called drinking when your entire life takes place fully submerged? Edit: looked it up and answered my own question. Saltwater fish do drink because the salty water draws water from their less salty bodies. Freshwater fish do not drink however, their bodies are saltier than the surrounding water so they hydrate by osmosis.
I worked on steam powered oil tankers built in the early 70's. We had two flash evaporators that ran from bleed steam at sea. These took seawater, heated it, sprayed it into a vacuum chamber, then reheated it, and sprayed into a higher vacuum chamber before the brine was then pumped back overboard. Each stage created water vapour that was condensed by the seawater feed, thus heating the water. The chloride content was around 1ppm and each evaporator could make 120 tons of water per day. The water was used for engine room and boiler use while separate tanks stored water for domestic purposes. To make the water suitable for consumption, it was passed through a mineral tank and then two stages of UV sterilisation. The biggest problem we had was when the deck department were cleaning tanks and would "decant" the slops over the side without telling the engine room to change over suctions to the opposite side. Any oil caught in the water would be picked up by the auxiliary seawater pumps and get into the evaporators that would boil off the lighter fractions as kerosene which would then get into the water tanks and add to the Engineer's workload. Good old days of being at sea.
the NPS by Crater Lake has some reverse-osmosis machines inside of various buildings at the ranger station. Filling a five-gal took around thirty minutes, the set-up was largely the same as your testing demo.
I'm currently drafting for a big waste water treatment plant in Texas and there is so much more to these facilities than I would have ever thought. I really appreciate that cities invest into these types of things.
The real world is so complex.... I'm in programming and the software code I saw in my first job was way more complex than anything I've seen in school.
I live on a small island of 22km², desalination is the only way to get city water. Although the vast majority of homes have cisterns for rainwater recovery, the island has a fairly modern plant equipped with both desalination systems, reverse osmosis and desalination by vacuum/low pressure evaporation, for the latter the heat used is that of the waste incineration plant. But personally I rarely use city water as I have two cisterns under my house for a total of about 70m³ with charcoal-UVC filtration system. But it’s always good to have this backup.
Which island? That sounds so cool!
@@TucsonDude St Barthélemy, Caribbean 😉👍
I love that the shot of the sail boat cruising in the ocean was my home town - the Gold Coast Australia!
We talked a lot about the idea of mixture separation in my statistical physics class. It was very interesting because Entropy makes the separation much harder because of the energy required to lower the entropy (separate water and salt).
I live on a sailboat and am in the process of building a water maker system that processes saltwater and filters it to fill the drinking water tanks in my boat. This is very useful information.
What are you planning on doing with the brine that is produced?
Hopefully store it for inland disposal.
It's amazing how much harder it is to desalinate water than it seems like it should be
Well it’s easy to dissolve salt in water, and removing it is the reverse of that
I'm a chemist. It seems like it should be really hard, and it is. You're fighting both entropy and enthalpy.
it's actually really easy. Collect rainwater. Done. but of course he didn't bother to cover that method.
@@SoloRenegadeHe explicitly noted this option in the video
@@nahometesfay1112 why didn't you give a time stamp? where was the discussion on how to implement it, on how it works, etc.? At 14:30 he INDIRECTLY mentions rainwater, but not rainwater collection. He's referencing ground water, lakes, and rivers. "if mother nature isn't dropping enough water for your particular area" this is wrong, and demonstrates his lack of understanding of rainwater collection and how it's done in such an environment.
This is pretty well done and answers some questions I have been wondering about.
There are quite a few desalination plants in the Cyclades in Greece. For example, the little fresh water that the island of Syros (about 20000 people I think) goes towards things like the hospital or the production of a local traditional product that needs good water. The desalinated water isn't usually drunk though.
If you can't source locally produced natural seawater, homemade is fine too
How much energy does it take to separate humor from engineering?
@@BS-vx8dg Less than it takes to artificially inject humor into engineering. ;)
In addition to the thousands of of plants on land around the world, there are thousands more because almost every naval ship and probably most commercial ships also use desalination to provide most of their water needs. The 30 year old ships that I served on had some nasty water, but it was drinkable (barely so) and the salt levels were low enough not to mess up your bodies balance. That was in the 90s. We also got tons of bottle water training in the middle east which was all desalinated. Those plants actually made water you could stand to drink. P.S. I love the eyeballs on the reverse osmosis machine. :)
I was on the Enterprise, which at the time I was onboard was over 30 years old. But our water was better than the tap water here in Las Vegas. Hard water is the worst. Of course I drank a lot of soda in those years which helps with the taste, but I drank tons of water from the drinking fountains because you have to working in the engineering plants, I don't remember it tasting bad. And of course the soda we got in the middle east was also desal. water.
@jimmym3352 I generally don't do tapwater unless it's fileted anymore. Even in small town USA you never know what's in the water until after its to late. Just like Camp Lejeune and Flint MI. A small town near me had some carcinogens above acceptable levels for over a year. No one knew until the water department sent out a letter saying it had been cleaned up. I assume you are a sailor. Semper Fi brother.
@@curtisroberts9137 water quality where I live in Australia is sometimes rough as well, I was supplying rain water to a couple of friends' families in the late 90s and early aughts because they were constantly getting sick otherwise, it's gotten better but still had times when a whiff of the water has been "I'm just not going to shower for a few days"...
@@cericat I had an aunt that lived in the mountains of Colorado. Their well was all mineral water. Smelled of sulfur most days. Lots of 5 gallon jugs of drinking water delivered there.
off the coast of California it is always foggy because the water is always cold. I think you can easily collect this water in the fog with condensers in the ocean and with some pumps to pump it to land with undersea pipes. much cheaper than using energy to evaporate or use costly reverse osmosis filters
I always had the idea of combining Nuclear power and a distillation center into one giant megacomplex: -The nuclear power plant literally works like a giant steam mill -The water is released through those traditional smoke stacks -Why not just use seawater so you kill 2 birds with one stone? Energy + Clean water -The only caveat would be the cleaning that would be needed
unfortunately,some radiation WILL escape into the water
I live half a mile from the Carlsbad plant. Thank you, Grady, for covering it! It’s been an excellent resource and source of pride.
ok
If you found out how the private company pay fines for dumping chemicals and paying off employees you wouldn't be as proud. Its a real dirty job and cutting corners in a hands on job like this puts people in danger who work there. Great source of water though...
Who is Carl and why is he bad?
@@youtubezombiesNono, you've got it wrong. It's possessive, they just removed the apostrophe for logistical reasons. It's actually Carl's bad desalination plant.
Title: Harnessing Water intake in desalination plants from mesopelagic (below epipelagic) region I'd like to propose an idea that has possible potential to help the desalination industry. Imagine a desalination plant that deploys an intake pipe from mesopelagic region to the surface, and then pumps its feedwater from the opening of this large pipe on the sea surface. This pipe will continue to fill due to the capillary action and we do not need energy-intensive pumps to bring that "cleaner" water to the surface. There are several compelling reasons to explore this approach: 1. Reduced Biofouling: Drawing water from greater depths could significantly reduce the risk of biofouling, a persistent challenge in desalination. By avoiding the epipelagic region where microorganisms thrive, we can minimize fouling and maintenance costs. 2. Potential for Lower Suspended Particle Concentration: mesopelagic waters typically have lower concentrations of suspended particles compared to surface waters. This could lead to system longevity and reduced costs. 3. Environmental Impact: Deploying a possible parallel line for brine disposal at the same depth can mitigate the environmental impact of brine discharge. This approach allows for more efficient dilution and dispersion, reducing harm to marine ecosystems. 4. Significant Savings: Energy savings, reduced maintenance costs, and improved desalination efficiency could translate into significant economic benefits for the industry. I invite you to share your thoughts, ideas, and expertise on this proposal. #WaterTreatment #Desalination #Innovation #Sustainability
Very informative video. I never have put much effort into founding out why they weren't de-salting salt water in africa altho it always bogeled me. Glad to stumble upon this well made piece :)
Yesssss finally, I am obsessed with this topic..... We need a way for clean drinking water in the future that is cheap and easy
I lived in a small Florida gulf coast city for years and this is how they got their water. It was very good. The only time I noticed a difference is if we filled the bath tub - the water had a greener appearance than what I was used to seeing in other cities. But again there were no taste or other useage issues for us.
My god. That's such a turn off!
Idk how you drank the Florida tap water. 🫣
@@ohio_dino Simple, it's cheaper than bottled water and isn't unsafe to drink. And in the past, it was the only game in town, as commercial bottled water on a wide scale is actually fairly recent. As in, I remember when bottled water was becoming common, and I am not old. More often, you would have water distribution stations where you put in say a quarter for a gallon of actually fresh water, which would be poured into the jug/bottle you brought with you, of paid extra for one to be provided for you to be reused. This was, and still is, common in places in the US where the tap water is of dubious quality and safety for consumption despite purification work. There are regions in this country where I will not drink tap water because of that. Most are in the Midwest, where local corruption actually made the water dubious to drink at the best of times, courting poisoning from industrial runoff or typhoid at the worst due to the ones supplying the water not investing properly in water purification, or keeping the systems well maintained due to taking the cheap route and pocketing the difference when they aren't outright embezzling the funds. A good bit of advice is to ask the locals if they drink the local water, and to generally not do so outside of major metropolitan areas anyway. What's good for general use like washing, bathing or showering, is not necessarily something you may want to drink. And yes, I am talking from experience here. Far less of a problem today, but it's still there. All it took was getting typhoid once to learn that lesson.
Desalinated water, depending on the desalination method and the plant, can have a vastly different flavor profile, when it actually has one, than what most of us are used to, though. And the slight green coloring may have been a dye so you would know the water was safe to drink.
@@jgkitarelman… it’s insane that a highly developed country such as the US still hasn’t got some sort of national initiative in place to provide equitable access to drinking water.
"Well, the instructions didn't say not to." Best advice ever lol. Love your vids. Very interesting.
I have a dehumidifier machine that takes up to 30 liters of water per day out of the air. Because this machine is made to dry the air of humid rooms like basements and not to produce water, the waste water of this machine is no drinking water. Inside that machine is a big fan and a compressor like in a refrigerator. The fan moves the humid air to the cold area of the refrigerator. The moisture is condensing and flows into a container. The water still contains some dust from the air if there is any in that room. To make it drinkable it needs to be filtered and some minerals have to be added. The advantage of this way to make water is that you can make it wherever the air is warm and humid. You don't need fluid water and there is no salty waste water. A disadvantage is the high energy consumption of the compressor. But if supplied with solar energy this might be not a problem.
wrong. No minerals needed. Rain water is drinkable (obviously) and is mineral free as distilled water the humans have used forever.
As a labprofessional I will just copy that sand-in-pot approach for my garagelab. It`s quite smart since its realy stable in holding the temperature.
I was just wondering about desalination yesterday! It’s super cool to learn about the engineered world even if this isn’t something I’m studying. Thanks for informing the masses Grady!
What is the theoretical minimum amount of energy that forms the lower bound
Nuclear powerplants are basically just "big waterboilers." Many of them are of obvious reasons situated near oceans. In them you get a lot of desalinated water steam in them, which easily can be collected and used as drinking water, and many nuclear power plants has that dual function: generate electricity and desalinate water. THIS is the easiest and cheapest way.
I've been wondering for years now if we could develop a piece of large machinery that operates off of tidal currents, consumes salt water that is constantly surrounding it, and desalinates it right there to be put in storage containers to be retrieved, or pumped back to land
Thank you, the camera shots, narration and editing are perfection. The small scale examples you built are a fun little break from other channels summed up wiki info dumps 👌✨
Hearing even the suggestion of private entities owning and controlling the water supply is pretty nauseating...
You think your municipal water supply isn't making bank off of you? They just do it by outlawing competition. My private family-owned water supplier out in the country charges half what my coworkers in the cities are paying, for water drawn from the same source lake and pumped 10 times farther. My rural electric co-op is significantly cheaper too.
@@brad5938 They literally cannot "make bank" as they are non-profit.
Private companies will ALWAYS operate more efficiently than government. Better yet, get several private entities involved and costs will get pushed down even more.
@@tilton417 Google searches "record profits" .. and confirmed.
@@brad5938 the price of freedom, right?
Distillation can be a lot cheaper, especially considering it doesn't need to worry about all the other purification and waste disposal steps, once you remember that you don't even need to boil water. It only needs to evaporate. Small quantities of water in a thin film on a warm surface evaporate easily. It's actually super simple for individuals to distill and condense drinking water. It's only difficult at scale.
I’m an engineer on an oil tanker, we have an evaporator. We use heat from our main engines cooling water. And an ejector pump to create a vacuum, fun fact. Water boils at a lower temp while under vacuum. Our water is usually 1ppm salinity.
Also there is the issue of biofouling where bacteria grow on the membranes and clog them after a while. It turns out to be very difficult problem to fully address.
Slow sand filters, followed by UV lamps, then activated carbon filters.
@@Simple_But_Expensive $$$$
@@thejman5552 His user name checks out.
@@bradley3549 Lollll
Just add salt to kill the bacteria
Water conservation methods are often more cost effective than desalinization as well. A municipality can spend a lot of money fixing leaks and implementing water saving policies before you get to the point of using desalinization.
Especially in places like california where it actually rains a lot and they just don't have the infrastructure to store the water
You can also implement grey water systems to help save the actually important water. We use water on a lot of things that don't actually need to be of human drinkable quality such as toilets and watering plants, there's no point in these systems using the expensive and rare freshwater and instead they might as well use waste water from other processes or water from less clean sources. You can implement this both on a municipal level and a private level, ie. in your own house you can have your toilets reuse water from the shower or washing machine while on a municipal level grey water can be reused in industry.
We can also focus on building those billboards that capture moisture from the air and turn it into potable water as well.
One advantage of using distillation is that if it's done in a clean way, the left over dry salt could be sold and used for table salt...
A really interesting video showing how complex the workings of desalination plants are,I learned a lot about how little I know about this process,but great to watch and come away with a bit more knowledge.
I'd like to know why the "Ocean Vapor Towers" approach doesnt make more sense than these methods, it seems a logical way to get fresh-water from salt-water and it leverages cycles so nature is doing a significant chunk of the work
It's slow per liter of water treated compared to other methods. Thus for a given amount of water the equipment has to be MUCH larger. (more expensive)
Basically scale, the number of towers you would need is astronomical
construction cost vs output. running cost isn't everything
At that point you're basically engaged in a small geoengineering project since you're trying to change the local climate and that is basically impossible to predict because you have to factor in the entire global climate to figure out what will happen. No one in their right mind would sign off on spending millions on a project that you can't even guarantee the outcome of. If a region doesn't get a lot of rainfall then there's some pretty powerful natural forces behind it and it's fairly easy to conclude that humans can't easily influence that. Like climate change is only happening because our entire global civilization is engaged in the same activity and has been doing so for about two centuries so it really isn't easy to influence the climate of our planet. Also there's the fact that you can't necessarily directly use rainwater, we usually use groundwater which has spent thousands of years filtering through the ground to make it clean. Plants that draw directly from sources such as lakes and rivers still do need some amount of cleaning before it becomes safe to drink and it's susceptible to ground pollution, which an area that experiences little rainfall that would normally wash it out probably has a lot of.
Based on this video it seems that reverse osmosis is a *lot* more energy efficient than distillation. It may seem attractive to use sunlight directly for evaporation instead of electricity. However, if sunlight is plentiful it might still be more efficient to convert that into electricity and use it to run reverse osmosis.
I read an article about Dubai's Desalinization Plant in which it states they analyzed their salt waste and found it had precious metals in minuet amounts, but recoverable. They built the plant with a mineral and metal recovery process and are extracting Gold and other metals and it has been profitable. They are also limiting the amount of salt dumped back into the sea! I contacted the engineering staff at San Diego and asked they If they were aware of this and they said no.
It surprises me we can't do anything with the waste brine. It feels like it should be usable in salt harvesting fields or for other uses of sea water. I'm sure there's good technical reasons. Just hope we can overcome those technical issues and use that concentrated brine.
That much brine would be pure poison anywhere but the ocean. Not sure where the Middle East desal plants expels it but I'd guess it's far from the intake pipes.
Also, in the maritime community the operative statement is "The solution to pollution is dilution."
I really love how clear and understandable your videos are! Good work
Additional research is needed to conclude this.
This is a video I didn't expect, I had to instantly watch it. I've been working with membrane desalination for a while and it looks super simple but under the hood, reverse osmosis still looks like alchemy. Thanks for the video!
Yes I drank desal water for 5 years. I lived on USNB GTMO. Our water was cut off by Castro after the revolution. I toured the desal plant a few times in school. Pretty cool.
There is a good deal of entropic energy difference involved between fresh water (a highly ordered state) and seawater (low ordered or more chaotic state). This is why there is considerable amount of energy required to extract pure water from seawater. It takes energy to increase the order of a system. It works the other way as well. The figures I have seen say that every stream of fresh water entering the sea releases the energy equivalent of it falling 700 feet. Allow a flow of fresh water to pass through an osmotic barrier in to a fixed volume of seawater. The fresh water will want to draw through the barrier and that produces a high pressure in the fixed volume, which is available to be tapped to a turbine for electricity production. A better use of the brine from desalination would be to transport it to a region with fresh water streams and use it with that water in an osmotic power plant. One other consequence of the high pressures of reverse osmosis is that the OH- H+ concentration balance (ie neutral pH point) shifts under pressure so the output fresh water has to have it's acidity corrected to neutral.
Interesting video, I did some work (electrical distribution/transmission) related to the USBR’s Yuma Desalination plant. It’s purpose was to reduce the salinity of agricultural drainage water before it was put into the Colorado river to aid in meeting the requirements of the Colorado River Compact treaty obligations with Mexico.