Where does the salt go when you desalinate? At a large enough scale, would we risk salting some area (or body of water) to death?
My guess is we can just dump the salt back in. :)
Edit: actually add sources.
[1] https://ourworldindata.org/water-use-stress [2] https://oceanservice.noaa.gov/facts/oceanwater.html
In reality, the ocean is huge. So all that salt/garbage/whatever is increadibly uneavenly distributed and will naturally collect in certain areas. In the case of extra salt it could easily have an adverse effect on local ecosystems.
Also salt dissolves in water which is why desalination is needed in the first place. Really think for a moment about what are saying must be true.
The point is not that plastic dissolves I’m water, it’s that the saline concentration won’t be spread evenly throughout the entire expansive ocean without first increasing it locally.
> Really think for a moment about what are saying must be true.
Indeed.
Another user, commented that it should be okay to dispose, by releasing it over fast moving currents in deep waters. That makes sense to me. The water we're using will mostly come back to the oceans and we'll have eventual consistency of the water/salt balance (in that process at least). Not sure if I got it right, though.
Either way, I feel that disposal of brine will be a problem if done recklessly, like for example in coastal areas and only on ideal conditions by chance - which is how we dumped most things in the 20th century.
My belief is that we should think about regulation, if we want desalinized water in a industrial scale.
The ocean evaporates more fresh water from its surface than humans could ever possibly match by desalination, so that part is perfectly fine.
Just avoid dumping the saline in high concentration (which is easy to do).
https://www.ncbi.nlm.nih.gov/pubmed/24241776
Maybe if the plant can spread the salt water further it could be less of an issue?
So when doing commercial desalination you don't want to produce very high salinity output (because it means that at some point in the process you were getting fresh water from very salty water ==> more power).
Of course, this has to offset against the cost of pumping et al, so there's an optimal cost output salinity.
The TL;DR for most modern desalination plants is that the output salinity is not that high. Typically under 7% dissolved solids (versus the ocean at about 3.5%). Meaning that pumping it back into the ocean is fine.
To put it a different way: If the overall salinity of the body of water being desalinated rose appreciably, it would probably render the desalination plant uneconomic.
Now, it can still be just as toxic, and that has to be handled. But if properly diluted, then it should be equivalent to the ocean evaporating water, which happens constantly.
That's the key phrase here. Obviously, if you dump it back into the ocean such that it actually does not impact local salinity levels, its fine. But that's also true for essentially anything dumped into the ocean - if you can manage the dumping of a toxic chemical such that it has no impact, wouldn't it also be fine?
Of course if you go down that route much you realize that the output of sewage plants is safe for human consumption there is no technical reason not to put it back into the water supply and greatly reduce the need for makeup water.
Are you claiming this is comparable to an oil spill or eutherification?