5 ms·

Are you aware that desalination plants are a huge threat to marine life? Thias can't be the solution.

by karlkloss 5y ago

adt2bt 5y ago
Do you have a source? I was not aware and would like to learn more.
- germinalphrase 5y ago
  The brine is too salty for marine life causing dead zones.
- ivanech 5y ago
  "Brine, water comprising about five percent salt, often includes toxins such as chlorine and copper used in desalination, it said. By contrast, global sea water is about 3.5 percent salt." "Brine can cut levels of oxygen in seawater near desalination plants" https://www.reuters.com/article/us-environment-brine-idUSKCN1P81PX https://www.reuters.com/article/us-environment-brine-idUSKCN...
  - Ericson2314 5y ago
    Can we lay those huge tubes underwater to disperse it drip irrigation style? It's not like it's a lot of salt once diffused, especially with those glaciers melting. We're already assuming far more electricity, so I'm not too concerned about the energy required to pump the brine many miles out, just worried about capital and repair costs.
  - throwaway894345 5y ago
    I wonder if the salt can be converted into a useful byproduct? Or else if it can be disposed of in an environmentally-friendly way?
    - falcolas 5y ago
      It's not pure salt. It's just water with abnormally high salinity. It would require a fair bit of additional processing to make it useful.
      - throwaway894345 5y ago
        Evaporation pools?
        falcolas 5y ago
        Entirely possible (and occurring already in the south bay), but they scale poorly - they require very large tracts of land since the pools need to be fairly shallow. They're also fairly labor intensive, between harvesting, purifying, and transporting the resulting salt.
        throwaway894345 5y ago
        The salt has to be transported in any case (whether salt comes from a mine or from evaporation pools). Even if we don't make it into a byproduct but just put it in a big pit of salt adjacent the evaporation pools it would probably be fine (somewhere that we don't need to worry too much about it leeching into the environment, which is already a concern for evaporation pools). Not sure what applications of salt there are or how pure it needs to be (presumably there are other applications besides table salt)? Since we're already positing very cheap energy, we can probably also posit more efficient desalinization plants (resulting brine is even more concentrated, taking the load off of evaporation pools) since I'm assuming that the energy cost is the bottleneck in desalinization efficiency.
  - scythe 5y ago
    >often includes toxins such as chlorine and copper used in desalination This is very avoidable. Most extant desalination plants are in the Middle East and subject to relatively little environmental oversight. While desalination will always produce brine, introducing extra chemicals is something that can be solved at the technology level.
- macNchz 5y ago
  Here's an article about the problems with brine from desalination plants https://www.scientificamerican.com/article/slaking-the-worlds-thirst-with-seawater-dumps-toxic-brine-in-oceans/ https://www.scientificamerican.com/article/slaking-the-world...
PeterisP 5y ago
This can be a solution - perhaps it's not a good solution, but if the other options are worse, people will gladly trade a dead zone in the ocean to prevent a dead zone around where they live and grow their food.
scythe 5y ago
Desalination might be more appropriately located in the Gulf of California. There is extreme tidal variation (about 4 meters!) in the upper part of the Gulf, which means that released brine will be mixed with seawater more rapidly than in most coastal areas.
- aww_dang 5y ago
  >Sea-to-Sea plans would augment the declining volume of water flowing into the Salton Sea by importing water from either the Gulf of California or the Pacific Ocean. Because such ocean water will bring tens of millions of tons of new salts into the Salton Sea, such plans also need to either pump a lot of water out of the Salton Sea to export the millions of tons of salt, desalinate the water before it enters the Salton Sea, or run multiple desalination plants at the Salton Sea itself. https://pacinst.org/salton-sea-import-export-plans/ https://pacinst.org/salton-sea-import-export-plans/
  - scythe 5y ago
    Yeah, you're not going to do that without a ton of pumps. I ran the numbers once for a pipeline to the Salton Sea and it looks bad. However, if you built a canal (about ten meters wide and the same deep) and flooded the whole Imperial Valley (this isn't popular!), tidal variation would exchange all of the water on average about three times per year. There's an equation for pipe flow rate given a diameter and a pressure difference; the pipe you would need for the Salton is either unrealistically huge or has a really big pump. Hence, canal. I doubt it ever happens, of course, due to all the lost farmland/towns (and the "why bother?" factor). What I was referring to is entirely different: the desalination occurs in Mexico and fresh water is piped around.
    - aww_dang 5y ago
      The canal has economic advantages as well. There are some proposals suggesting (I don't how practical this is) to use geothermal plants in the Salton area to power the desalination. As to the pumps, isn't the valley below sea level? Therefore power could be generated from the flow?

Are you aware that desalination plants are a huge threat to marine life? Thias can't be the solution.

adt2bt 5y ago

Do you have a source? I was not aware and would like to learn more.

germinalphrase 5y ago
The brine is too salty for marine life causing dead zones.
ivanech 5y ago
"Brine, water comprising about five percent salt, often includes toxins such as chlorine and copper used in desalination, it said. By contrast, global sea water is about 3.5 percent salt." "Brine can cut levels of oxygen in seawater near desalination plants" https://www.reuters.com/article/us-environment-brine-idUSKCN1P81PX https://www.reuters.com/article/us-environment-brine-idUSKCN...
- Ericson2314 5y ago
  Can we lay those huge tubes underwater to disperse it drip irrigation style? It's not like it's a lot of salt once diffused, especially with those glaciers melting. We're already assuming far more electricity, so I'm not too concerned about the energy required to pump the brine many miles out, just worried about capital and repair costs.
- throwaway894345 5y ago
  I wonder if the salt can be converted into a useful byproduct? Or else if it can be disposed of in an environmentally-friendly way?
  - falcolas 5y ago
    It's not pure salt. It's just water with abnormally high salinity. It would require a fair bit of additional processing to make it useful.
    - throwaway894345 5y ago
      Evaporation pools?
      - falcolas 5y ago
        Entirely possible (and occurring already in the south bay), but they scale poorly - they require very large tracts of land since the pools need to be fairly shallow. They're also fairly labor intensive, between harvesting, purifying, and transporting the resulting salt.
        throwaway894345 5y ago
        The salt has to be transported in any case (whether salt comes from a mine or from evaporation pools). Even if we don't make it into a byproduct but just put it in a big pit of salt adjacent the evaporation pools it would probably be fine (somewhere that we don't need to worry too much about it leeching into the environment, which is already a concern for evaporation pools). Not sure what applications of salt there are or how pure it needs to be (presumably there are other applications besides table salt)? Since we're already positing very cheap energy, we can probably also posit more efficient desalinization plants (resulting brine is even more concentrated, taking the load off of evaporation pools) since I'm assuming that the energy cost is the bottleneck in desalinization efficiency.
- scythe 5y ago
  >often includes toxins such as chlorine and copper used in desalination This is very avoidable. Most extant desalination plants are in the Middle East and subject to relatively little environmental oversight. While desalination will always produce brine, introducing extra chemicals is something that can be solved at the technology level.
macNchz 5y ago
Here's an article about the problems with brine from desalination plants https://www.scientificamerican.com/article/slaking-the-worlds-thirst-with-seawater-dumps-toxic-brine-in-oceans/ https://www.scientificamerican.com/article/slaking-the-world...

PeterisP 5y ago

This can be a solution - perhaps it's not a good solution, but if the other options are worse, people will gladly trade a dead zone in the ocean to prevent a dead zone around where they live and grow their food.

scythe 5y ago

Desalination might be more appropriately located in the Gulf of California. There is extreme tidal variation (about 4 meters!) in the upper part of the Gulf, which means that released brine will be mixed with seawater more rapidly than in most coastal areas.

aww_dang 5y ago
>Sea-to-Sea plans would augment the declining volume of water flowing into the Salton Sea by importing water from either the Gulf of California or the Pacific Ocean. Because such ocean water will bring tens of millions of tons of new salts into the Salton Sea, such plans also need to either pump a lot of water out of the Salton Sea to export the millions of tons of salt, desalinate the water before it enters the Salton Sea, or run multiple desalination plants at the Salton Sea itself. https://pacinst.org/salton-sea-import-export-plans/ https://pacinst.org/salton-sea-import-export-plans/
- scythe 5y ago
  Yeah, you're not going to do that without a ton of pumps. I ran the numbers once for a pipeline to the Salton Sea and it looks bad. However, if you built a canal (about ten meters wide and the same deep) and flooded the whole Imperial Valley (this isn't popular!), tidal variation would exchange all of the water on average about three times per year. There's an equation for pipe flow rate given a diameter and a pressure difference; the pipe you would need for the Salton is either unrealistically huge or has a really big pump. Hence, canal. I doubt it ever happens, of course, due to all the lost farmland/towns (and the "why bother?" factor). What I was referring to is entirely different: the desalination occurs in Mexico and fresh water is piped around.
  - aww_dang 5y ago
    The canal has economic advantages as well. There are some proposals suggesting (I don't how practical this is) to use geothermal plants in the Salton area to power the desalination. As to the pumps, isn't the valley below sea level? Therefore power could be generated from the flow?