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What is the expected timeline for desalination technology? Even with continued investment all efforts have seemed to plateau at some point when costs and feasib

What is the expected timeline for desalination technology? Even with continued investment all efforts have seemed to plateau at some point when costs and feasibility reaches a critical point.

deagle50 7y ago
Isn't feasibility a function of the cost of alternative options? If our current methods dry up, what is considered nonviable today suddenly becomes normal.
- thinkcontext 7y ago
  How would reverse osmosis filtration (the dominant desal method) "dry up"?
  - swampthinker 7y ago
    He's referring to traditional sources of fresh water like aquifers, rivers, and lakes.
barbecue_sauce 7y ago
The major issue with desalination as far as I can tell is that it produces toxic brine that proves problematic as far as disposal.
- aesh2Xa1 7y ago
  That's a good point. All the salt and other solute needs to go someplace. As that stuff comes from the ocean one might suggest it goes back into it at a controlled rate. The biggest challenge I'd read about had been energy costs, so this headline appears to be great news.
- kardos 7y ago
  If the toxic brine is purely the extracts from the ocean water, you can toss it back into the ocean (with appropriate dilution). If the toxic brine has a bunch of additives that are a byproduct of the desal, then this is indeed problematic. The article mentions that this method eliminates the need for chemical additives so this could be a pretty low-impact method of desal.
  - ninkendo 7y ago
    > you can toss it back into the ocean (with appropriate dilution) ... what are you going use to dilute the brine? The water you just desalinated? What's the point then? Seems to me if your input is seawater, and your output is a separated-out set of {fresh water, saltier sea water}, and you put the saltier sea water back in the sea, you're going to create a localized concentration of high salinity, no? Seems kind of unavoidable to me.
    - sachdevap 7y ago
      Not necessarily. You could mix it in processed sewage. Assuming processed sewage is appropriately disposed off in the sea at limited locations with precautions, this should work. One concern may be the sheer volume from desalination might overburden the sewage disposal.
- ortusdux 7y ago
  I've spoken with a few oceanographers about this and the brine can be easily pumped back into the ocean with very minimal impact as long as you are smart about it. The effluent from a normal desal system is only twice the concentration of the source seawater. The key is to place your plant so you can reintroduce the brine into a fast moving and deep waterway. One interesting ancillary benefit of having a source of brine is that it makes extracting desired minerals and elements from seawater much cheaper and easier. I have personally seen a system that extracts uranium from seawater. Current implementations yield yellow-cake at twice the market rate. There is ongoing work to tie it into a desal plant and bring that cost down. There is also work to combine it with lithium extraction.
- pacaro 7y ago
  This presumably depends on what your water source is. If you are desalinating groundwater, then yes the brine is going to be an issue, for seawater less so
- mixmastamyk 7y ago
  You can dump it on land to evaporate, then sell some and bury the rest.
deleted 7y ago
[deleted]
ars 7y ago
Israel gets 40% of its fresh water from desalination https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in_Israel#Seawater_desalination_(2000s) https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in... Israel went from having severe water shortages if there was no rain (plus environmental damage from overdrawing lakes) to being perfectly fine. And the costs are not too bad either. Israel also is the world leaded by far in controlling water leaks, which helps reduce water demand, and they also reuse greywater for farming. Other places with water shortages could do the same.

What is the expected timeline for desalination technology? Even with continued investment all efforts have seemed to plateau at some point when costs and feasibility reaches a critical point.

deagle50 7y ago

Isn't feasibility a function of the cost of alternative options? If our current methods dry up, what is considered nonviable today suddenly becomes normal.

thinkcontext 7y ago
How would reverse osmosis filtration (the dominant desal method) "dry up"?
- swampthinker 7y ago
  He's referring to traditional sources of fresh water like aquifers, rivers, and lakes.

barbecue_sauce 7y ago

The major issue with desalination as far as I can tell is that it produces toxic brine that proves problematic as far as disposal.

aesh2Xa1 7y ago
That's a good point. All the salt and other solute needs to go someplace. As that stuff comes from the ocean one might suggest it goes back into it at a controlled rate. The biggest challenge I'd read about had been energy costs, so this headline appears to be great news.
kardos 7y ago
If the toxic brine is purely the extracts from the ocean water, you can toss it back into the ocean (with appropriate dilution). If the toxic brine has a bunch of additives that are a byproduct of the desal, then this is indeed problematic. The article mentions that this method eliminates the need for chemical additives so this could be a pretty low-impact method of desal.
- ninkendo 7y ago
  > you can toss it back into the ocean (with appropriate dilution) ... what are you going use to dilute the brine? The water you just desalinated? What's the point then? Seems to me if your input is seawater, and your output is a separated-out set of {fresh water, saltier sea water}, and you put the saltier sea water back in the sea, you're going to create a localized concentration of high salinity, no? Seems kind of unavoidable to me.
  - sachdevap 7y ago
    Not necessarily. You could mix it in processed sewage. Assuming processed sewage is appropriately disposed off in the sea at limited locations with precautions, this should work. One concern may be the sheer volume from desalination might overburden the sewage disposal.
ortusdux 7y ago
I've spoken with a few oceanographers about this and the brine can be easily pumped back into the ocean with very minimal impact as long as you are smart about it. The effluent from a normal desal system is only twice the concentration of the source seawater. The key is to place your plant so you can reintroduce the brine into a fast moving and deep waterway. One interesting ancillary benefit of having a source of brine is that it makes extracting desired minerals and elements from seawater much cheaper and easier. I have personally seen a system that extracts uranium from seawater. Current implementations yield yellow-cake at twice the market rate. There is ongoing work to tie it into a desal plant and bring that cost down. There is also work to combine it with lithium extraction.
pacaro 7y ago
This presumably depends on what your water source is. If you are desalinating groundwater, then yes the brine is going to be an issue, for seawater less so
mixmastamyk 7y ago
You can dump it on land to evaporate, then sell some and bury the rest.

deleted 7y ago

[deleted]

ars 7y ago

Israel gets 40% of its fresh water from desalination https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in_Israel#Seawater_desalination_(2000s) https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in... Israel went from having severe water shortages if there was no rain (plus environmental damage from overdrawing lakes) to being perfectly fine. And the costs are not too bad either. Israel also is the world leaded by far in controlling water leaks, which helps reduce water demand, and they also reuse greywater for farming. Other places with water shortages could do the same.