Why Is Desalination So Difficult?

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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.

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.

As a water treatment specialist it feels good to be seen. The RO segment was dead on. TDS and scaling are constant challenges.

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.

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.

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.

Love this channel. As a trained EE I wish my education had this kind of practical experiments and thought-experiments.

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.

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.

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.

Having companies privatize desal water like you mentioned is incredibly scary. Water, Electricity, and Internet should all be public utilities.

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.

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

Spoken like a true engineer... "The instructions didn't say to not run salt water through the pump"

You are a gifted presenter. I engineer stuff all day but get almost giddy sometimes when you release a new story.

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.

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.

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 .

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.