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Salt release is already a huge environmental concern with exiting desalinization systems. Energy consumption and installation costs aren't the sole (and probabl

Salt release is already a huge environmental concern with exiting desalinization systems. Energy consumption and installation costs aren't the sole (and probably not the main) problems. Desalinization is inherently a pollution.

Someone 5y ago
A small part of it can be avoided by combining this with a salt evaporation pond (https://en.wikipedia.org/wiki/Salt_evaporation_pond https://en.wikipedia.org/wiki/Salt_evaporation_pond) Problem will be that we’ll get way too much salt (a few grams of salt per liter of water), so it won’t help much.
throwaway894345 5y ago
Why not release the salt back to the sea? Presumably it would not increase the salt content of the ocean very much considering the vastness of the ocean and the sheer quantity of fresh water that is being added to it by melting glaciers, etc? What am I missing?
- dystroy 5y ago
  The salt you release isn't instantly diluted in the whole ocean and we're speaking, for a plant, of millions cubic meters of salt enriched water per day. The release area is just dying.
  - shellfishgene 5y ago
    Can you provide a source for that? I dove near a desalination plant exit pipe in Saudi, the impact on the marine live did not seem to big in the area. But it was a small plant for a few thousand people and we did not do a proper assessment. I don't doubt there is an effect, but am not convinced that the "release area just dying" is correct.
    - EricE 5y ago
      https://www.keiken-engineering.com/en/brine-disposal-how-efficient-desalination-plants-get-rid-of-toxic-remnant/ https://www.keiken-engineering.com/en/brine-disposal-how-eff... Brine disposal is indeed a complex issue. Should be noted the above URL is from a desalinization industry proponent so I would say it's probably a little more optimistically biased but it was one of the better summaries I found so it still has value from that perspective. If you do more digging around each of the solutions they discuss you can find more pro's/con's for each and you will quickly find out that it is a pretty significant issue.
      - shellfishgene 5y ago
        The link does not really show any evidence that marine ecology at brine outlets is disturbed. It does however suggest that pouring the brine on land or roads (for de-icing) are alternative solutions, which I doubt ;). I was more thinking of proper studies, such as reviewed in [0], which says in the abstract: "Ecological monitoring studies have found variable effects ranging from no significant impacts to benthic communities, through to widespread alterations to community structure in seagrass, coral reef and soft-sediment ecosystems when discharges are released to poorly flushed environments. In most other cases environmental effects appear to be limited to within 10s of meters of outfalls." So, impact yes, but "release area is just dying", probably not. [0] https://www.sciencedirect.com/science/article/abs/pii/S0043135410002903 https://www.sciencedirect.com/science/article/abs/pii/S00431...
  - throwaway894345 5y ago
    This makes sense to me. I wonder how feasible it would be to release the saltier water over a broader area to reduce the salinity in any one area? Also, there are at least some ecological benefits to increasing the amount of fresh water. An extreme example is the lake that appeared in the middle of a desert in the United Arab Emirates. I have no idea how we weigh one against another.
    - SV_BubbleTime 5y ago
      Now you’re paying for salt transportation again.
      - throwaway894345 5y ago
        Not if you have many small desalination plants distributed over a larger area. This would work well for less-densely populated areas.
  - dfilppi 5y ago
    That is acceptable
- kevstev 5y ago
  Why not just collect the salt, and sell it as... salt? Even if its not ok for cooking, it should be fine for roads? I am sure there are other industrial uses for salt.
  - SV_BubbleTime 5y ago
    Actual salt is rarely used on the roads in the USA anymore. Majority use magnesium chloride now. Don’t know about the rest of the world. Lots of reasons, pros and cons. I work in automotive and hate it.
  - EricE 5y ago
    Salt from roads is seriously contaminating our environment and significantly impacting farming in more and more areas. Ever hear of the Romans salting the earth of people the conquered? It was so they couldn't grow crops - yet we routinely do this to ourselves - pretty daft.
    - throwaway894345 5y ago
      We also farm in a way that is almost optimized for erosion of topsoil. We’ve already lost a third of it and it only renews on geological timescales. Daft is too polite.

Someone 5y ago

A small part of it can be avoided by combining this with a salt evaporation pond (https://en.wikipedia.org/wiki/Salt_evaporation_pond https://en.wikipedia.org/wiki/Salt_evaporation_pond) Problem will be that we’ll get way too much salt (a few grams of salt per liter of water), so it won’t help much.

throwaway894345 5y ago

Why not release the salt back to the sea? Presumably it would not increase the salt content of the ocean very much considering the vastness of the ocean and the sheer quantity of fresh water that is being added to it by melting glaciers, etc? What am I missing?

dystroy 5y ago
The salt you release isn't instantly diluted in the whole ocean and we're speaking, for a plant, of millions cubic meters of salt enriched water per day. The release area is just dying.
- shellfishgene 5y ago
  Can you provide a source for that? I dove near a desalination plant exit pipe in Saudi, the impact on the marine live did not seem to big in the area. But it was a small plant for a few thousand people and we did not do a proper assessment. I don't doubt there is an effect, but am not convinced that the "release area just dying" is correct.
  - EricE 5y ago
    https://www.keiken-engineering.com/en/brine-disposal-how-efficient-desalination-plants-get-rid-of-toxic-remnant/ https://www.keiken-engineering.com/en/brine-disposal-how-eff... Brine disposal is indeed a complex issue. Should be noted the above URL is from a desalinization industry proponent so I would say it's probably a little more optimistically biased but it was one of the better summaries I found so it still has value from that perspective. If you do more digging around each of the solutions they discuss you can find more pro's/con's for each and you will quickly find out that it is a pretty significant issue.
    - shellfishgene 5y ago
      The link does not really show any evidence that marine ecology at brine outlets is disturbed. It does however suggest that pouring the brine on land or roads (for de-icing) are alternative solutions, which I doubt ;). I was more thinking of proper studies, such as reviewed in [0], which says in the abstract: "Ecological monitoring studies have found variable effects ranging from no significant impacts to benthic communities, through to widespread alterations to community structure in seagrass, coral reef and soft-sediment ecosystems when discharges are released to poorly flushed environments. In most other cases environmental effects appear to be limited to within 10s of meters of outfalls." So, impact yes, but "release area is just dying", probably not. [0] https://www.sciencedirect.com/science/article/abs/pii/S0043135410002903 https://www.sciencedirect.com/science/article/abs/pii/S00431...
- throwaway894345 5y ago
  This makes sense to me. I wonder how feasible it would be to release the saltier water over a broader area to reduce the salinity in any one area? Also, there are at least some ecological benefits to increasing the amount of fresh water. An extreme example is the lake that appeared in the middle of a desert in the United Arab Emirates. I have no idea how we weigh one against another.
  - SV_BubbleTime 5y ago
    Now you’re paying for salt transportation again.
    - throwaway894345 5y ago
      Not if you have many small desalination plants distributed over a larger area. This would work well for less-densely populated areas.
- dfilppi 5y ago
  That is acceptable
kevstev 5y ago
Why not just collect the salt, and sell it as... salt? Even if its not ok for cooking, it should be fine for roads? I am sure there are other industrial uses for salt.
- SV_BubbleTime 5y ago
  Actual salt is rarely used on the roads in the USA anymore. Majority use magnesium chloride now. Don’t know about the rest of the world. Lots of reasons, pros and cons. I work in automotive and hate it.
- EricE 5y ago
  Salt from roads is seriously contaminating our environment and significantly impacting farming in more and more areas. Ever hear of the Romans salting the earth of people the conquered? It was so they couldn't grow crops - yet we routinely do this to ourselves - pretty daft.
  - throwaway894345 5y ago
    We also farm in a way that is almost optimized for erosion of topsoil. We’ve already lost a third of it and it only renews on geological timescales. Daft is too polite.