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The other day I was reading an article here about how one big problem with desalination plants is that they produce raw salt that increases the salinity of wate

The other day I was reading an article here about how one big problem with desalination plants is that they produce raw salt that increases the salinity of water near them. The consensus was "oh well the ocean is big", but if you put these things around where you're dumping the salt, at least you could get a little bit of the energy that you spent removing the salt back. So desalination becomes more efficient.

DoctorOetker 3y ago
The raw salt can be recombined with returning wastewater, so on condition that the expenses are made to properly balance the flows the problem of brine disposal is not as big as usually depicted. However it is a very big problem if the authorities refuse to implement these appropriate measures. A more explicit way this type of technology as depicted in the article could be used: given access to multiple baths of different salinity, the energy recovered from mixing 2 strongly saline baths can be used to desalinate a less saline bath. Consider the following map (2.7 MB png): https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2019/05/global_sea-surface_salinity/19390092-1-eng-GB/Global_sea-surface_salinity.png https://www.esa.int/var/esa/storage/images/esa_multimedia/im... Clearly tracts of land largely separating seas of different salinity like Spain / Morocco [or for example Colombia, Panama, Costa Rica, Honduras, Mexico] have access to 2 distinct salinities. So by recovering energy from dumping the Mediterranean salt into the Atlantic, the energy can be recovered to desalinate either Atlantic waters or other accessible baths of saline but lower salinity water, like a transformer. A second point: if sufficiently scaled up it could provide baseload or buffer the mismatch between energy production and consumption, however one ought to reflect on the consequences on the local ecosystem if the water baths are not contained in man-made receptacles.
uoaei 3y ago
You could also just pump the brine into evaporation fields and harvest sea salt.
catapart 3y ago
That was my first thought, too: "can this generate power with brackish water? Because, if so, there's a banger of a one-two shot with that previous article about desalinating water for drinking, and then hooking up the outflow to something that can generate power with it. That would be a pretty badass little home resource installation."

DoctorOetker 3y ago

The raw salt can be recombined with returning wastewater, so on condition that the expenses are made to properly balance the flows the problem of brine disposal is not as big as usually depicted. However it is a very big problem if the authorities refuse to implement these appropriate measures. A more explicit way this type of technology as depicted in the article could be used: given access to multiple baths of different salinity, the energy recovered from mixing 2 strongly saline baths can be used to desalinate a less saline bath. Consider the following map (2.7 MB png): https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2019/05/global_sea-surface_salinity/19390092-1-eng-GB/Global_sea-surface_salinity.png https://www.esa.int/var/esa/storage/images/esa_multimedia/im... Clearly tracts of land largely separating seas of different salinity like Spain / Morocco [or for example Colombia, Panama, Costa Rica, Honduras, Mexico] have access to 2 distinct salinities. So by recovering energy from dumping the Mediterranean salt into the Atlantic, the energy can be recovered to desalinate either Atlantic waters or other accessible baths of saline but lower salinity water, like a transformer. A second point: if sufficiently scaled up it could provide baseload or buffer the mismatch between energy production and consumption, however one ought to reflect on the consequences on the local ecosystem if the water baths are not contained in man-made receptacles.

uoaei 3y ago

You could also just pump the brine into evaporation fields and harvest sea salt.

catapart 3y ago

That was my first thought, too: "can this generate power with brackish water? Because, if so, there's a banger of a one-two shot with that previous article about desalinating water for drinking, and then hooking up the outflow to something that can generate power with it. That would be a pretty badass little home resource installation."