6 ms·

Ways to think about water (2015)

51 points by siruva07 5y ago

newyankee 5y ago
It is my genuine hope that desalination becomes cheap enough in the next decade that most coastal places will depend on it instead of any other source for domestic and industrial use. Taking that as a baseline i hope transporting water in flat topography inland up to 100 to 200 km inland from coasts also becomes cheap enough. All depends on material science breakthroughs, cheap renewable energy, technology sharing and scaling.
- billfruit 5y ago
  What about atmospheric water extraction/harvesting? Is it a viable alternative with current technology?
  - newyankee 5y ago
    For remote locations without any other alternative. Mostly for drinking and high value uses, still very expensive.
  - deleted 5y ago
    [deleted]
  - tsimionescu 5y ago
    Not really, since water vapor must eliminate huge amounts of energy to turn back into liquid water - each kg of water vapor will dissipate 2.27MJ to turn into a kg of water at 100C. Since this is a thermodynamic limit, there's no enginerring around it.
    - zdragnar 5y ago
      Ostensibly, heat pumps could dual-purpose as AC and dehumidification, but if you have enough water for a heat pump, the condensation you collect probably isn't going to be very significant. Edit: My point being you don't have to supply 2MJ of energy, you need to move it. That can be done for less.
      - tsimionescu 5y ago
        > My point being you don't have to supply 2MJ of energy, you need to move it. That can be done for less. Understood, but the point is still that you need to keep something cold enough for vapor to condense, while the condensation of 1 kg of water is dissipating enough heat to bring 5.4 kg of water from 0 to 100C. Even if just moving the heat around, there's just too much of it.
- VBprogrammer 5y ago
  To me the ideal of using technology like this is a brute force solution. I'm always suspect of the scientific credentials behind the permaculture movement but I suspect that they have got this one right. Slow water down high in the landscape, let it absorb into the ground, build leaky damn structures and many of the water security issues go away. I think this has been proven fairly well in a number of semi-arid areas such as parts of India.
  - martin_a 5y ago
    > I think this has been proven fairly well in a number of semi-arid areas such as parts of India. I've recently seen a video on YouTube where they did this. They dug a "hole"/artificial lake with a capacity of over, I think, 140 million litres. They used that to create "a wet spot" which slowly started to transform the surrounding landscape. Plants, trees, bushes obviously started from around that lake but moved farther and farther from it as the soil became better. This does not solve any problems with salt water, but it could possibly a solution for areas where there's "only" very little water available.
- mrfusion 5y ago
  Also it seems like a lot of agricultural water use doesn’t actually get to the plants. It just goes around the roots and sinks into the ground. Could we grow things like almond trees in large concrete basins and collect any water not used by the roots?
  - pstuart 5y ago
    At least aggressive drip irrigation should be a default mode.
  - beerandt 5y ago
    Ground infiltration is the least bad thing to happen. Keeping the water near the surface just results in more evaporation loss, and side effects for soil quality like concentration of salts. Water infiltrating the ground will keep the soil "primed" for water absorption and storage, and prevent runoff and erosion and flash flooding. (Think about watering a potted plant with completely dried out soil.) Plus it will just go towards recharging the water table.
- tedjdziuba 5y ago
  Desal is inefficient and hugely destructive to the environment. This old saw comes up in California every now and then, but if we were able to build the most efficient desal plants available today, it would take 500 plants along the California coastline to supply all of California's water. Aside from being an eyesore, it would ruin the coastal ecology.
- coding123 5y ago
  It is already super cheap and transported automatically. We just need to catch more of it. Rainwater capture will be the next big thing. Right now our idea of rainwater capture is letting it go back into the ground. That's fine, it kinda worked but not really. Now we need to capture more. Finally, yes, maybe everyone should get an RV style toilet, have no dishwasher and get their pressure reduced to 30 PSI.
- photochemsyn 5y ago
  There's a fundamental energy demand for removing salt from seawater and creating drinkable water that can't be avoided. Hence, desalination is fundamentally tied to the price of energy. These costs can easily bankrupt cities that try to rely on desalination to meet demand (for example, California droughts cause hydropower to go offline right when water demand is highest). Using fossil fuels to power desalination in the global warming era is also a really bad idea. It might work in certain locales (lots of sunshine plus solar panels, perhaps), but the costs will always be high, and it's going to be very uneconomical for agricultural-scale needs.
  - throwaway1777 5y ago
    People seem to always forget about nuclear. Pairing nuclear plants with desalination is perfect because you also need water in most nuclear reactor designs.
    - teachrdan 5y ago
      That doesn't solve the problem of what to do with the salt and other chemicals removed via desalinization. You're left with literally toxic brine that has to be dumped somewhere, at the expense of the ecosystems you dump in. https://www.scientificamerican.com/article/slaking-the-worlds-thirst-with-seawater-dumps-toxic-brine-in-oceans/ https://www.scientificamerican.com/article/slaking-the-world...
      - throwaway1777 5y ago
        There are solutions besides straight up dumping the brine. Technology is evolving to handle this as desalination becomes more common. Of course the easiest thing is dumping it so some regulation may be required.
photochemsyn 5y ago
Odd quote from this article: "One interesting idea that has emerged in dry places (notably Australia and Israel) is water markets. These make sense on a pretty basic level: if something is scarce and valuable, I should be able to buy, sell, and speculate on it." Given that water is a fundamental necessity, it's supply should not be subject to rigged markets and monopolistic pricing, which is the norm when private investors try to take over natural monopolies (i.e. there's no 'competition' in water supply systems, rather like electricity markets.)
- saint_fiasco 5y ago
  Water bottles are much cheaper than batteries. For example, suppose that after a natural disaster some people are left without water and without power. It makes perfect sense to load some water bottles into a truck and drive over there to help them, but it would be very impractical to load a truck with enough batteries to make even a tiny bit of difference.
- jpollock 5y ago
  Water isn't a fundamental necessity (as in required for life) for 70-80% of the water used. Water markets aren't typically (maybe there are some?) aimed at individuals, they're aimed at commercial users (farms, power plants, data centers, factories). For example, see the : https://youtu.be/druiwE_GjRI?t=559 https://youtu.be/druiwE_GjRI?t=559 and the last section where they talk about waste. Pricing encourages factories to do things like recycle water on site.
  - TuringTest 5y ago
    How would you handle that 20% - 30% that is essential for life, if the rest is purely market-based?
  - jjoonathan 5y ago
    Yes, but pricing lubricates the slope towards the setup where Nestlé owns 100% of the water because they bid a pittance and the nearby town can't afford to outbid the pittance. Markets are a two-edged sword. One edge is "rich people can pay for factories to recycle water on site" but the other edge is "rich people matter, poor people don't." There's nothing wrong with trying to use edge #1 -- that's what capitalism is all about -- but edge #2 exists, is sharp, and has cut plenty of fingers off. People are leery of it for a reason.
21eleven 5y ago
Here's a different way to think about water: There is the theory that evolution is a process by which genes advance and proliferate. That livings things are just the pawns for their genes, life is a medium for a genetic super organism. But the genetic super organism is just a middle manager. Life does not exist for itself or for genes but for water. Living organisms were created within water and by water to be a vehicle that H2O can use to transcend the tyranny of gravity and explore space.
- tshaddox 5y ago
  Can probably take that a bit further and say it’s all for heat.
lmilcin 5y ago
> A man in a desert and a sailor at sea will think about water very differently. Maybe there are more sailors here and they may feel differently, but that's not true for me. For me open ocean is about as close to desert as possible and sea water is like sand. Probably the only thing different is that you can stuff a lot more fresh water onto a boat that you can stuff on a camel or expedition car. And the way it is stuffed means there is less chance you will loose it. And sailing is incredibly involved and technical compared to say riding a camel so you have other problems that occupy your mind. So it probably takes less space in your mind while you are sailing than while you are crossing Sahara. But if your boat quits on you in the middle of an ocean it is more or less as if camel or expedition car did. You lend your life to the elements and to your equipment. If it fails and you can't fix it, you die. --- I had a discussion with somebody that incessantly wants me to "save" water supposedly because many people have shortage of it. I tell her "Our water comes from local river. We don't have water shortage. Any water that I do not use will just happily flow to the sea. Any water that I use will get cleaned up and dumped into the same river from which it came, to happily continue its journey to the sea." Seems the argument doesn't work. People are strange sometimes...
- tshaddox 5y ago
  I’m not sure your dismissal of “saving water” makes sense, or rather, your dismissal would apply just as well to any situation where one’s personal use of water will not directly cause a shortage of water for someone else. The whole point of recommending people to save water isn’t that one’s own water conservation will directly cause a measurable re-allocation of water to someone else. It’s more akin to moral advice, something like “act in a way that would have good outcomes if everyone acted that way.” I suppose it’s okay to explicitly dismiss all moral recommendations of that form, but it’s worth noting that this form is extremely common and not something I would call “strange.” It’s basically the same moral recommendation as “don’t butt in line even if no one is going to stop you.” To map that idea directly onto your situation, I guess it would be something like “if 10 million people moved to the vicinity of your small river, there probably would be a water shortage that would require everyone to be conscientious about their water usage.”
  - 5y ago
SeanFerree 5y ago
Excellent article!

51 points by siruva07 5y ago

It is my genuine hope that desalination becomes cheap enough in the next decade that most coastal places will depend on it instead of any other source for domestic and industrial use. Taking that as a baseline i hope transporting water in flat topography inland up to 100 to 200 km inland from coasts also becomes cheap enough. All depends on material science breakthroughs, cheap renewable energy, technology sharing and scaling.

billfruit 5y ago
What about atmospheric water extraction/harvesting? Is it a viable alternative with current technology?
- newyankee 5y ago
  For remote locations without any other alternative. Mostly for drinking and high value uses, still very expensive.
- deleted 5y ago
  [deleted]
- tsimionescu 5y ago
  Not really, since water vapor must eliminate huge amounts of energy to turn back into liquid water - each kg of water vapor will dissipate 2.27MJ to turn into a kg of water at 100C. Since this is a thermodynamic limit, there's no enginerring around it.
  - zdragnar 5y ago
    Ostensibly, heat pumps could dual-purpose as AC and dehumidification, but if you have enough water for a heat pump, the condensation you collect probably isn't going to be very significant. Edit: My point being you don't have to supply 2MJ of energy, you need to move it. That can be done for less.
    - tsimionescu 5y ago
      > My point being you don't have to supply 2MJ of energy, you need to move it. That can be done for less. Understood, but the point is still that you need to keep something cold enough for vapor to condense, while the condensation of 1 kg of water is dissipating enough heat to bring 5.4 kg of water from 0 to 100C. Even if just moving the heat around, there's just too much of it.
VBprogrammer 5y ago
To me the ideal of using technology like this is a brute force solution. I'm always suspect of the scientific credentials behind the permaculture movement but I suspect that they have got this one right. Slow water down high in the landscape, let it absorb into the ground, build leaky damn structures and many of the water security issues go away. I think this has been proven fairly well in a number of semi-arid areas such as parts of India.
- martin_a 5y ago
  > I think this has been proven fairly well in a number of semi-arid areas such as parts of India. I've recently seen a video on YouTube where they did this. They dug a "hole"/artificial lake with a capacity of over, I think, 140 million litres. They used that to create "a wet spot" which slowly started to transform the surrounding landscape. Plants, trees, bushes obviously started from around that lake but moved farther and farther from it as the soil became better. This does not solve any problems with salt water, but it could possibly a solution for areas where there's "only" very little water available.
mrfusion 5y ago
Also it seems like a lot of agricultural water use doesn’t actually get to the plants. It just goes around the roots and sinks into the ground. Could we grow things like almond trees in large concrete basins and collect any water not used by the roots?
- pstuart 5y ago
  At least aggressive drip irrigation should be a default mode.
- beerandt 5y ago
  Ground infiltration is the least bad thing to happen. Keeping the water near the surface just results in more evaporation loss, and side effects for soil quality like concentration of salts. Water infiltrating the ground will keep the soil "primed" for water absorption and storage, and prevent runoff and erosion and flash flooding. (Think about watering a potted plant with completely dried out soil.) Plus it will just go towards recharging the water table.
tedjdziuba 5y ago
Desal is inefficient and hugely destructive to the environment. This old saw comes up in California every now and then, but if we were able to build the most efficient desal plants available today, it would take 500 plants along the California coastline to supply all of California's water. Aside from being an eyesore, it would ruin the coastal ecology.
coding123 5y ago
It is already super cheap and transported automatically. We just need to catch more of it. Rainwater capture will be the next big thing. Right now our idea of rainwater capture is letting it go back into the ground. That's fine, it kinda worked but not really. Now we need to capture more. Finally, yes, maybe everyone should get an RV style toilet, have no dishwasher and get their pressure reduced to 30 PSI.
photochemsyn 5y ago
There's a fundamental energy demand for removing salt from seawater and creating drinkable water that can't be avoided. Hence, desalination is fundamentally tied to the price of energy. These costs can easily bankrupt cities that try to rely on desalination to meet demand (for example, California droughts cause hydropower to go offline right when water demand is highest). Using fossil fuels to power desalination in the global warming era is also a really bad idea. It might work in certain locales (lots of sunshine plus solar panels, perhaps), but the costs will always be high, and it's going to be very uneconomical for agricultural-scale needs.
- throwaway1777 5y ago
  People seem to always forget about nuclear. Pairing nuclear plants with desalination is perfect because you also need water in most nuclear reactor designs.
  - teachrdan 5y ago
    That doesn't solve the problem of what to do with the salt and other chemicals removed via desalinization. You're left with literally toxic brine that has to be dumped somewhere, at the expense of the ecosystems you dump in. https://www.scientificamerican.com/article/slaking-the-worlds-thirst-with-seawater-dumps-toxic-brine-in-oceans/ https://www.scientificamerican.com/article/slaking-the-world...
    - throwaway1777 5y ago
      There are solutions besides straight up dumping the brine. Technology is evolving to handle this as desalination becomes more common. Of course the easiest thing is dumping it so some regulation may be required.

photochemsyn 5y ago

Odd quote from this article: "One interesting idea that has emerged in dry places (notably Australia and Israel) is water markets. These make sense on a pretty basic level: if something is scarce and valuable, I should be able to buy, sell, and speculate on it." Given that water is a fundamental necessity, it's supply should not be subject to rigged markets and monopolistic pricing, which is the norm when private investors try to take over natural monopolies (i.e. there's no 'competition' in water supply systems, rather like electricity markets.)

saint_fiasco 5y ago
Water bottles are much cheaper than batteries. For example, suppose that after a natural disaster some people are left without water and without power. It makes perfect sense to load some water bottles into a truck and drive over there to help them, but it would be very impractical to load a truck with enough batteries to make even a tiny bit of difference.
jpollock 5y ago
Water isn't a fundamental necessity (as in required for life) for 70-80% of the water used. Water markets aren't typically (maybe there are some?) aimed at individuals, they're aimed at commercial users (farms, power plants, data centers, factories). For example, see the : https://youtu.be/druiwE_GjRI?t=559 https://youtu.be/druiwE_GjRI?t=559 and the last section where they talk about waste. Pricing encourages factories to do things like recycle water on site.
- TuringTest 5y ago
  How would you handle that 20% - 30% that is essential for life, if the rest is purely market-based?
- jjoonathan 5y ago
  Yes, but pricing lubricates the slope towards the setup where Nestlé owns 100% of the water because they bid a pittance and the nearby town can't afford to outbid the pittance. Markets are a two-edged sword. One edge is "rich people can pay for factories to recycle water on site" but the other edge is "rich people matter, poor people don't." There's nothing wrong with trying to use edge #1 -- that's what capitalism is all about -- but edge #2 exists, is sharp, and has cut plenty of fingers off. People are leery of it for a reason.

21eleven 5y ago

Here's a different way to think about water: There is the theory that evolution is a process by which genes advance and proliferate. That livings things are just the pawns for their genes, life is a medium for a genetic super organism. But the genetic super organism is just a middle manager. Life does not exist for itself or for genes but for water. Living organisms were created within water and by water to be a vehicle that H2O can use to transcend the tyranny of gravity and explore space.

tshaddox 5y ago
Can probably take that a bit further and say it’s all for heat.

lmilcin 5y ago

> A man in a desert and a sailor at sea will think about water very differently. Maybe there are more sailors here and they may feel differently, but that's not true for me. For me open ocean is about as close to desert as possible and sea water is like sand. Probably the only thing different is that you can stuff a lot more fresh water onto a boat that you can stuff on a camel or expedition car. And the way it is stuffed means there is less chance you will loose it. And sailing is incredibly involved and technical compared to say riding a camel so you have other problems that occupy your mind. So it probably takes less space in your mind while you are sailing than while you are crossing Sahara. But if your boat quits on you in the middle of an ocean it is more or less as if camel or expedition car did. You lend your life to the elements and to your equipment. If it fails and you can't fix it, you die. --- I had a discussion with somebody that incessantly wants me to "save" water supposedly because many people have shortage of it. I tell her "Our water comes from local river. We don't have water shortage. Any water that I do not use will just happily flow to the sea. Any water that I use will get cleaned up and dumped into the same river from which it came, to happily continue its journey to the sea." Seems the argument doesn't work. People are strange sometimes...

tshaddox 5y ago
I’m not sure your dismissal of “saving water” makes sense, or rather, your dismissal would apply just as well to any situation where one’s personal use of water will not directly cause a shortage of water for someone else. The whole point of recommending people to save water isn’t that one’s own water conservation will directly cause a measurable re-allocation of water to someone else. It’s more akin to moral advice, something like “act in a way that would have good outcomes if everyone acted that way.” I suppose it’s okay to explicitly dismiss all moral recommendations of that form, but it’s worth noting that this form is extremely common and not something I would call “strange.” It’s basically the same moral recommendation as “don’t butt in line even if no one is going to stop you.” To map that idea directly onto your situation, I guess it would be something like “if 10 million people moved to the vicinity of your small river, there probably would be a water shortage that would require everyone to be conscientious about their water usage.”
- 5y ago

SeanFerree 5y ago

Excellent article!