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MIT’s New Desalination System Produces Freshwater That Is “Cheaper Than Tap Water” (scitechdaily.com)
submitted 2 years ago by to c/technology@slrpnk.net
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[–] 5 points 2 years ago* (last edited 2 years ago) (1 child)

This might have an interesting potential yet I am quite sceptical.

Desalination doesn't just get rid off the salt but also most of the water's minerals. Lack of minerals in the water used everyday can be harmful for human health and also for agriculture. This poor water can't provide enough minerals or worst even adsorb the ones from the human body same with the soil. This is why many desalination plants have remineralization process by adding some or reusing minerals extracted from the brine.

If such a system is deployed it would have to address this problem as well as providing solutions to dispose or utilize the brine.

Remineralization of desalinated water: Methods and environmental impact

Israeli Scientists Fear Public Health Risks from Desalinated Seawater

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  • [–] 12 points 2 years ago*

    Remineralization is a well known and solved problem in existing processes (RO and distillation). I personally built and ran a high performance RO that produced < 5ppm TDS water on my farm, and experienced the ill effects of drinking demineralized water. Excess thirst, urination and muscle cramps.

    The WHO published an excellent study on this issue. The issue is not an actual lack of minerals, as we get very little of our minerals from water, but the fact that your body is not designed to absorb water with zero solutes. Effectively the sensors in your gut go out of span and you end up dumping solutes from your bloodstream instead.

    The solution is very simple and cheap, that is to add any salt so that your body can detect it. Sodium chloride is fine, being "normal salt" of course, but I add potassium chloride as most of us get too much sodium as is. This is available as "salt substitute".

    A pinch in a glass or a tablespoon in a 5 gallon jug is enough to completely eliminate any ill effects. Commercially as mentioned you can blend back some of the brine stream. It's not really a problem as long as you don't effectively deliver DI water to your customers by accident.

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