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When your straw gets clogged with ice cream, do you dip your fingers into your milkshake to unclog it? You add your osmosis filter at the end of a long flexibl

by stereo 3y ago

When your straw gets clogged with ice cream, do you dip your fingers into your milkshake to unclog it? You add your osmosis filter at the end of a long flexible hose. For maintenance, you reel it back in.

chongli 3y ago
Straws don’t work beyond 10 metres. You need all your pumping equipment either at the bottom or distributed along the pipe. Either way, that’s going to put a ton of strain on your “flexible hose” when you try to reel it back in. And what if it breaks? Oops!
- Enginerrrd 3y ago
  I mean, we do it with oil. ...At least sort of. Usually the wells are pressurized so pumping isn't a concern, but there's a surprising amount of infrastructure involved down at depth and the maintenance of that infrastructure is significant but largely a solved problem. Obviously economics probably favor it when oil is $75/barrel compared to ~$3 maybe for the fresh water, but still.
  - chongli 3y ago
    Your estimate for the water is way too high. I pay $2 USD (as of today's exchange rates) for a cubic metre of water from my local utility. That works out to about 32 cents per "barrel" of water. A $75 USD barrel of oil is 234 times as expensive as the same amount of water. From what I can gather, oil rigs have profit margins below 20% (at best) and margins decline as the pressure in the well head drops, until they become totally unprofitable and shut down to wait for oil prices to go up. Water prices would have to increase by more than 2 orders of magnitude to make this strategy begin to approach profitability!
    - jjav 3y ago
      > I pay $2 USD (as of today's exchange rates) for a cubic metre of water from my local utility. A cubic meter is ~264 gallons. Here in my area of California (CA has lots of water agencies, so YMMV) 1000 gallons costs $38.66 (varies based on total consumption). So that's $10.21 for a cubic meter.
- schiffern 3y ago
  >Straws don’t work beyond 10 metres. ...straws surrounded by air don't work beyond 10 meters, because the external pressure at the bottom of the pipe doesn't exceed 1 atmosphere. Obviously this isn't true if the pipe does down into the ocean.

by stereo 3y ago

chongli 3y ago

Straws don’t work beyond 10 metres. You need all your pumping equipment either at the bottom or distributed along the pipe. Either way, that’s going to put a ton of strain on your “flexible hose” when you try to reel it back in. And what if it breaks? Oops!

Enginerrrd 3y ago
I mean, we do it with oil. ...At least sort of. Usually the wells are pressurized so pumping isn't a concern, but there's a surprising amount of infrastructure involved down at depth and the maintenance of that infrastructure is significant but largely a solved problem. Obviously economics probably favor it when oil is $75/barrel compared to ~$3 maybe for the fresh water, but still.
- chongli 3y ago
  Your estimate for the water is way too high. I pay $2 USD (as of today's exchange rates) for a cubic metre of water from my local utility. That works out to about 32 cents per "barrel" of water. A $75 USD barrel of oil is 234 times as expensive as the same amount of water. From what I can gather, oil rigs have profit margins below 20% (at best) and margins decline as the pressure in the well head drops, until they become totally unprofitable and shut down to wait for oil prices to go up. Water prices would have to increase by more than 2 orders of magnitude to make this strategy begin to approach profitability!
  - jjav 3y ago
    > I pay $2 USD (as of today's exchange rates) for a cubic metre of water from my local utility. A cubic meter is ~264 gallons. Here in my area of California (CA has lots of water agencies, so YMMV) 1000 gallons costs $38.66 (varies based on total consumption). So that's $10.21 for a cubic meter.
schiffern 3y ago
>Straws don’t work beyond 10 metres. ...straws surrounded by air don't work beyond 10 meters, because the external pressure at the bottom of the pipe doesn't exceed 1 atmosphere. Obviously this isn't true if the pipe does down into the ocean.