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I was so quick to criticize technology that I completely overlooked those points. Reading the article again, it’s embarrassing to see that I missed it when they

I was so quick to criticize technology that I completely overlooked those points. Reading the article again, it’s embarrassing to see that I missed it when they were emphasizing it so much. I have one more lingering criticism that I don’t think they addressed (I reread it twice). What happens to the salt after it’s removed? If they don’t have a filter, where does it go? Do they pump brine water back?

QuikAccount 4y ago
You can pump brine water back but if I recall you can't just dump it all back at once because it's so highly concentrated. Ideally you would be able to find an alternate use for it.
- MichaelApproved 4y ago
  For these small amounts, I doubt pumping it back out would be an issue but is that what they’re doing? I thought the metal plates were collecting the salt but the article and video don’t make it clear.
  - nullc 4y ago
    In CEDI at least the ions are trapped in a resin then are driven across a membrane by a charge, on the other side of the membrane you run water to flush them out. Some comment in the article left me thinking they end up trapping them in the media and have to reverse charge to release them so I assume it would operate pulsed and presumably have a valve to dump the output during regen. Though I'm a little confused in that normally CEDI is used after RO because the CEDI media is pretty sensitive to fouling and also doesn't work well when the water conductivity is highly variable. Maybe they solve the fouling with charge reversal. ...who knows, because popular coverage of this stuff never hits on the important parts and almost never links the relevant publications. There are many ways to make drinkable water from seawater-- making them some useful mixture of energy efficient, cost effective, portable, waste-water efficient, and reliable is the actual hard part.
  - bruce511 4y ago
    given the size of the thing it's likely to be positioned very close to the water source, so I expect it just dumps it outside the device. I mean, if I was running it on a boat, or next to the sea, I'd just basically pour the waste out right next to the device. And I agree, at ounces per hour there's no need to dilute the brine, just dumping it is fine.
tomxor 4y ago
Note that they are not merely aiming for portability, but efficient portability. This particular passage is suggestive of their device being more efficient than RO at small scales, although no figures are given for comparison: > Commercially available portable desalination units typically require high-pressure pumps to push water through filters, which are very difficult to miniaturize without compromising the energy-efficiency of the device, explains Yoon.
- MichaelApproved 4y ago
  Good point. I wish articles like these would include figures. I’d love to know what they calculate RO efficiency to be at small scales and how far away they are from beating it. Sure, that might be boring for some readers but they could throw a couple of sentences about it at the bottom.

QuikAccount 4y ago

You can pump brine water back but if I recall you can't just dump it all back at once because it's so highly concentrated. Ideally you would be able to find an alternate use for it.

MichaelApproved 4y ago
For these small amounts, I doubt pumping it back out would be an issue but is that what they’re doing? I thought the metal plates were collecting the salt but the article and video don’t make it clear.
- nullc 4y ago
  In CEDI at least the ions are trapped in a resin then are driven across a membrane by a charge, on the other side of the membrane you run water to flush them out. Some comment in the article left me thinking they end up trapping them in the media and have to reverse charge to release them so I assume it would operate pulsed and presumably have a valve to dump the output during regen. Though I'm a little confused in that normally CEDI is used after RO because the CEDI media is pretty sensitive to fouling and also doesn't work well when the water conductivity is highly variable. Maybe they solve the fouling with charge reversal. ...who knows, because popular coverage of this stuff never hits on the important parts and almost never links the relevant publications. There are many ways to make drinkable water from seawater-- making them some useful mixture of energy efficient, cost effective, portable, waste-water efficient, and reliable is the actual hard part.
- bruce511 4y ago
  given the size of the thing it's likely to be positioned very close to the water source, so I expect it just dumps it outside the device. I mean, if I was running it on a boat, or next to the sea, I'd just basically pour the waste out right next to the device. And I agree, at ounces per hour there's no need to dilute the brine, just dumping it is fine.

tomxor 4y ago

Note that they are not merely aiming for portability, but efficient portability. This particular passage is suggestive of their device being more efficient than RO at small scales, although no figures are given for comparison: > Commercially available portable desalination units typically require high-pressure pumps to push water through filters, which are very difficult to miniaturize without compromising the energy-efficiency of the device, explains Yoon.

MichaelApproved 4y ago
Good point. I wish articles like these would include figures. I’d love to know what they calculate RO efficiency to be at small scales and how far away they are from beating it. Sure, that might be boring for some readers but they could throw a couple of sentences about it at the bottom.