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Thread: Tier 1 Water Shortage for SW appears inevitable

  1. Top | #21
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    Quote Originally Posted by Jokodo View Post
    Quote Originally Posted by DBT View Post

    I was thinking more along the lines of the local environment where tons of salt is being pumped into the ocean, which may impact on local ecosystems....presumably it takes a while to disperse even while it is constantly being pumped. Which may be an issue, I don't really know.
    It doesn't take long to disperse. It's the ocean, it has currents and Eddie's.
    Make your discharge pipes long--release it below the level where most things live.

    Quote Originally Posted by Valjean View Post
    Quote Originally Posted by DBT View Post
    Most things having consequences, I wonder what the downside to large scale world wide desalinization may turn out to be.
    It would be salt; discharged back into the sea, it would create massive, hypersaline dead zones.

    "Eventual dispersion" doesn't matter. In most places dispersion would be slow: witness the eutrophic dead zones at the mouth of the Mississippi, or in some of the American Great Lakes -- and eutrophication is slow. Hypersalinity is fast. It can kill fish, coral or phytoplankton in minutes.
    The discharge water isn't all that salty. My understanding is that desalinization is normally done by reverse osmosis. As fresh water is extracted the salinity on the salty side goes up, it's harder to pump. Thus you are better off discharging the water without raising the salinity too much, especially if you have a system to recapture some of that energy. (You have high pressure water in the discharge--use that to turn a pump which pumps in more water. It's not 100% efficient so you still need power but not as much.)

    Quote Originally Posted by Jokodo View Post
    Also, overall salinity is actually dropping with melting glaciers permanently adding fresh water, while the water taken out doesn't stay out very long.
    Quote Originally Posted by Jimmy Higgins View Post
    Quote Originally Posted by Jokodo View Post
    Also, overall salinity is actually dropping with melting glaciers permanently adding fresh water, while the water taken out doesn't stay out very long.
    It does if used for agriculture.
    Quote Originally Posted by Jimmy Higgins View Post
    I drink water and expel the water same day. Water for agriculture takes much longer than a day to go back into the water cycle.
    Longer, but on a scale to affect the salinity of the oceans it doesn't matter. And if it somehow became one do some old fashioned salt harvesting and toss the salt in a dry cave somewhere.

    Quote Originally Posted by barbos View Post
    Just don't dump all brine in one place. Wikipedia says sea water must be treated with chemicals before processed in desalination plant and it could be a problem too. And 3 kWh per 1 m^3 of water, that's not that expensive
    Looking at local rates we pay 10x as much for water as it would cost to desalinate that much water. It's not cost prohibitive by any means.

  2. Top | #22
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    The seas are big. People used to think about the Chesapeake Bay and Lake Erie similarly, just keep dumping the waste there, it won't matter.

    Back on topic, the problem isn't water, it's population.

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    Quote Originally Posted by T.G.G. Moogly View Post
    The seas are big. People used to think about the Chesapeake Bay and Lake Erie similarly, just keep dumping the waste there, it won't matter.

    Back on topic, the problem isn't water, it's population.
    The difference being salt, or slightly healthier water, isn't otherwise rare in the oceans, quite the opposite, so adding what amounts to very small quantities relative to what's already there is quite different to adding or rare compounds or even just massive amounts of organic matter.

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    Quote Originally Posted by Jokodo View Post
    Quote Originally Posted by T.G.G. Moogly View Post
    The seas are big. People used to think about the Chesapeake Bay and Lake Erie similarly, just keep dumping the waste there, it won't matter.

    Back on topic, the problem isn't water, it's population.
    The difference being salt, or slightly healthier water, isn't otherwise rare in the oceans, quite the opposite, so adding what amounts to very small quantities relative to what's already there is quite different to adding or rare compounds or even just massive amounts of organic matter.
    So we're in agreement?

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    This sounds like the thinking that got us into a climate crisis

    It taksd energy to distill water. Saudi Arabia has the biggest desaninixation oricess in te workd with cheap oil ebergy, yet it is not enough.i

    The idea that desalinization is going to provide for the LA area is fantasy. Post war LA grew only because they got water from elsewhere.

    The quetion of sustainable population has to be a dressed or nature will decide it for us. Looks like it will be the latter.

    There are always consequences. Large scale air conditioning in Phoenix actually changed the local climate

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    It appears that some do see it as a potential problem:


    The salt and chemicals in the brine left over from desalination can threaten local marine ecosystems

    ''Growing populations and tightening water supplies have spurred people in many places—including the Middle East, Australia, California and China—to look to the oceans and other salty waters as a source of new drinking water. But desalination plants are energy intensive and create a potentially environment-harming waste called brine (made up of concentrated salt and chemical residues), which is dumped into the ocean, injected underground or spread on land.

    Despite the ecological threats, “there was no comprehensive assessment about brine—how much we produce,” says Manzoor Qadir, assistant director of the United Nations University Institute on Water, Environment and Health. So he and his colleagues calculated that figure and found it is 50 percent greater than the desalination industry’s previous rough estimate. In fact, it is enough to cover Florida with 30 centimeters of brine every year.''

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    Human over-population is the important problem of our age

    Quote Originally Posted by steve_bank View Post
    This sounds like the thinking that got us into a climate crisis ...

    The que[s]tion of sustainable population has to be a dressed or nature will decide it for us. Looks like it will be the latter.
    Yes. Climate change and depletion of freshwater sources are just two on a list of problems caused by excessively high human population and our unsustainable lifestyle. A huge portion of the Earth's arable land is exploited by humans, so habitat destruction is another symptom of the underlying problem: Amphibians and insects are two classes of animals which have been severely affected on land, but the ecology of the vast oceans have also been degraded by man's actions. High populations facilitate pandemics. To feed the huge human population, anti-environment agriculture methods are used. For example, phosphates for fertilizers are not recycled; both the mining and the disposal of phosphates are troublesome.

    But for some reason. message-board participants discount this issue, and even announce that this is a disproven problem! Inevitably they link to some video with graphics proudly claiming that human population will level off at about ten billion. But ten billion is already much too high. Technological progress is viewed as a panacea — unmetered energy from fusion is coming any day now! — but technology comes with its own risks.

    Quote Originally Posted by steve_bank View Post
    There are always consequences. Large scale air conditioning in Phoenix actually changed the local climate
    Explain? I know that covering soil with asphalt is a problem. I believe you about air conditioning but have forgotten the reason.

  8. Top | #28
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    Quote Originally Posted by steve_bank View Post
    This sounds like the thinking that got us into a climate crisis

    It taksd energy to distill water. Saudi Arabia has the biggest desaninixation oricess in te workd with cheap oil ebergy, yet it is not enough.i

    The idea that desalinization is going to provide for the LA area is fantasy. Post war LA grew only because they got water from elsewhere.

    The quetion of sustainable population has to be a dressed or nature will decide it for us. Looks like it will be the latter.

    There are always consequences. Large scale air conditioning in Phoenix actually changed the local climate
    That's why you build nuke plants to run the desalinators.

  9. Top | #29
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    Quote Originally Posted by Loren Pechtel View Post
    Quote Originally Posted by Jimmy Higgins View Post
    I drink water and expel the water same day. Water for agriculture takes much longer than a day to go back into the water cycle.
    Longer, but on a scale to affect the salinity of the oceans it doesn't matter. And if it somehow became one do some old fashioned salt harvesting and toss the salt in a dry cave somewhere.
    LA alone uses about 13,000 million gallons of water a month. Salt is about 3.5% of the mass of water. If the math is right, that works out to about 2 million CY (2 million tons) of salt a month.

    And this is saying you can pull the salt out. I doubt that is possible, as that'd likely require a good amount of time, which means you aren't dealing with salt, but brine, extremely environmentall toxic brine. And the volume numbers grow even larger.

  10. Top | #30
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    Quote Originally Posted by Jimmy Higgins View Post
    Quote Originally Posted by Loren Pechtel View Post
    Quote Originally Posted by Jimmy Higgins View Post
    I drink water and expel the water same day. Water for agriculture takes much longer than a day to go back into the water cycle.
    Longer, but on a scale to affect the salinity of the oceans it doesn't matter. And if it somehow became one do some old fashioned salt harvesting and toss the salt in a dry cave somewhere.
    LA alone uses about 13,000 million gallons of water a month. Salt is about 3.5% of the mass of water. If the math is right, that works out to about 2 million CY (2 million tons) of salt a month.

    And this is saying you can pull the salt out. I doubt that is possible, as that'd likely require a good amount of time, which means you aren't dealing with salt, but brine, extremely environmentall toxic brine. And the volume numbers grow even larger.
    Old fashioned salt harvesting = let seawater into ponds in a hot climate, let it evaporate, gather up the salt. Slow but it works.

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