Desalination system could produce freshwater that is cheaper than tap water

Re:Desalination system could produce freshwater that is chea... by toast0 on Wednesday September 27, 2023 @10:40PM (#37684535)

If you had a lot of fresh water runoff, you might use that fresh water for drinking rather than desalinating seawater though.

But... If you are using this water for drinking, it's going to come back through the sewage system, and maybe you can dilute the brine with outflows from local sewage treatment plants.

Depending on details, the combined outflow could be more or less salty than the seawater input to the desal plant.

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Re:Desalination system could produce freshwater that is chea... by CydeWeys on Wednesday September 27, 2023 @10:44PM (#37684558)

Only some of it comes back through the sewage system. A lot of it just ends up lost to evaporation, or being incorporated into products. Think about your typical use of water to irrigate farmland (which is the majority use of water in many places); you don't really get any of that back as freshwater discharge at all. If you did, that means they're irrigating too much to the point that they're flooding their fields and causing runoff.

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Re:Desalination system could produce freshwater that is chea... by toast0 on Wednesday September 27, 2023 @11:16PM (#37684771)

Sure, but do people really pay desal prices to irrigate fields?

Also, a lot of places are using desal to augment other supplies. If you've got 15% of your municipal water supply coming from desal, sewage treatment outflows should be significant compared to brine.

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Re:Desalination system could produce freshwater that is chea... by CydeWeys on Thursday September 28, 2023 @03:24PM (#37694434)

I mean, they do if they're watering their lawns and that's where their water is coming from.

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