A new solar desalination system takes in saltwater and heats it with natural sunlight. The system flushes out accumulated salt, so replacement parts aren’t needed often, meaning the system could potentially produce drinking water that is cheaper than tap water.
One of the challenging issues with a complex problem is that the problem is not solved until the whole thing is solved.
One of the nice things about a complex problem is that you don’t have to solve the whole thing at once in order to make progress toward a complete solution.
I don’t know the state of the art on dealing with waste brine. If that is already deemed insoluble above a certain scale, then we better not invest in anything that exceeds that scale. On the other hand, if research into handling waste brine in sustainable ways is ongoing and making progress, then why not continue attacking the extraction problem?
I mean if the water is being used for drinking then put the brine into the treatment plant outfall so that it matches the salinity of the body of water it’s being discharge into…
It’s not quite that simple. After extracting water, matching salinity would require extracting salt or adding water. It’s not that there aren’t sources of water that can be used for salinity matching, including the output of sewage treatment, the reality is that it probably makes more sense to treat that water than to desalinate in the first place.
Extracting the salts might be a source of valuable minerals and metals, but there is still no free lunch.
As far as I know, we still would be putting stuff back that doesn’t make a good match for what we took. That means depending on the natural environment for dilution and “treatment”. That has been an ongoing problem for humanity. We’re very good at exceeding the capacity of the environment to cope with our wastes.
I completely understand the comment about perpetual motion machines, but tend to think that it’s more of a scale management problem than a strict prohibition.
I live in Vancouver BC, our drinking water comes essentially from mountain run off and snow melt in two local watersheds. We get less and less every year.
My thought is that with distillation we could use brackish/ river water, then concentrate the brine until it’s as salty as ocean water and put it in the ocean.
My thought about sewer outfalls was that adding the brine to the sewer flow should pretty much match the salinity of the source because any volume that goes into the pipes comes out of the sewers. (minus some evaporation).
As long as nobody is using drinking water for irrigation, the output does pretty closely match the input.
But my point was that we can treat that water for use and reuse. That way, the desalination is kept to a minimum.
Hey a perpetual motion machine violates the laws of physics. But why let that stop me from designing a power plant that uses one. One day will fix those pesky physics laws.
The impossibility of perpetual motion is not a reason to shut down research into methods of making power production and power consumption more efficient.
Are you saying that dealing with the waste brine is impossible in any way, shape, or form and that this is a reason to not pursue desalination research?
I used to be municipal water treatment plant operator (Level 2). I’m well aware that treatment waste is something that must be dealt with in any plant that does more than just disinfection.
I already admitted to not being up on the state of the art, but I was under the impression that there are potentially viable methods of dealing with waste brine in environmentally sustainable ways. Perhaps not at a scale that allows literally every human to use desalination for all needs, but that there are cases where desalination is a good solution.
My curiosity has been piqued. I will, of course, start looking for resources on waste brine management, but any pointers you have will be much appreciated.