I teach remedial reading in middle school and one unit we read about and study is the impending Water Crisis, the lack of fresh, clean water and how it will affect people in the future(some even affected now).
I show a video, which I’ll put at the end of this post. In the video, it goes over the main issues with desalination:
cost
brine production(hypersalty water)
energy use
My question is for people who are into science and study the latest developments. Does it look like one day in the next 25-50 years, we will improve desalination enough to completely solve the water crisis? I saw that the ocean contains at least 45 Billion Gallons of water…per person on earth(someone do the math?). Anyway, it would easily solve our water crisis as much as cold fusion would solve our energy problems.
Is there hope for desalination in the future? When I was a kid in the 80’s, I thought we’d have it all figured out and be good to go. Nope, not yet.
Here I the video I show in class, which is really where I most recently learned about it issues.
Well, the supply of ocean water is a gazillion times bigger in volume than the supply of fresh water, so I would say yes. The criticism is the expense, but space travel is incredibly expensive, and we do that. I can’t speak for others, but I think not dying of thirst is a tad more important that going to Mars.
Yeah, I mean that is only one concern. I don’t know why, but brine apparently is a major problem. Pumping it back into the water is bad for the environment. I don’t get why they can not collect the brine and potentially extrat some of the salt from that…or do something with it.
I think the challenge will be getting the desalinated freshwater to remote inland areas that need it efficiently. We can’t just cover the earth with thousands of miles of pipelines that would be subject to high maintenance costs and possible sabotage. I see a mass migration of people creating overcrowding on the coastlines that will raise a variety of issues such as driving up housing costs near fresh water sources. As the planet gets warmer, we need less humans around to support, not more.
I said to about 1 billion over 150 years. That is a long time and it can be done without violence and grief.
Solar/Wind/Tide/Fission won’t be enough, we need Fusion, but no guarantees we achieve it. A lot less use is the other path.
There are many other conservation methods we can employ and the 1 billion was just an off the cuff figure. The number that Earth can sustain is probably higher with conservation and a lot more non-CO2 contributing energy sources.
Desalination is expensive, energy intense, and creates a lot of waste. It hasn’t caught on because there are cheaper and more passive ways to make more fresh water available, namely conservation. And dialing back agriculture in dry areas where a lot of people live (ag accounts for by far more water consumption than cities).
If desalination becomes cheaper by way of unlocking an energy easter egg like fusion, and we figure out what to do with the waste salt, then I can see it being more useful as a domestic supply, but for now managing existing fresh water supplies better is what we got.
The problem is there is a lot of it. We could use a fraction of it (and potentially bump this fraction up with new technology), but that’s still leaves a lot of brine that would have to be diluted and pumped (at additional energy expenditure) back into the sea.
If you have available contaminated fresh water. I live on the coast in an area prone to drought. We have a desal plant to supplement our reservoir. It supplies 30% of our drinking water.
Why? We’ve got lots of “useless” land, why can’t we make a bunch of huge shallow pools and just dump the brine into them, and then wait for the sun to do it’s thing? The water gets evaporated out, the dried out salt can be bull dozed into heaps or whatever (isn’t that what we mine salt from commercially already? Ancient salt deposits?) and then you pump more brine into the pools and repeat forever.
And if we are going to pump waste salty water great distances to “useless” land for disposal, we may as well just pump clean fresh water from places where there is abundance to places where there is not, if we are going to spend money on pipeline projects.
That makes sense in some areas. Otherwise, there’s still plenty of fresh water available around the world to use that may need some treatment to be drinkable. The Great Lakes aren’t drying up. The Mississippi isn’t going dry. So, if there is a water crisis I’m not seeing how desalinating ocean water is the widespread solution.
No to mention culturally and socially. Those with water abundance bristle at the idea of building pipelines exporting their water to areas where it is more scarce. Just ask anyone in the Pacific Northwest about California extending a straw from Shasta Lake to the Columbia River.
