Why is it difficult to turn seawater into drinking water?

Discussion in 'General Science & Technology' started by Saint, May 31, 2012.

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  1. Aqueous Id flat Earth skeptic Valued Senior Member

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    Yes I think that's the most basic and practical approach. I was also thinking about the solar collector for its high temperature and the hygienic advantage. But for starters I think it would be great if the world relief agencies set out to furnish one of these for every person in every area that could benefit from it.
     
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  3. Trippy ALEA IACTA EST Staff Member

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    I have a mental image in my head of using a solar collector to desalinate sea water, and produce electricity as well as potable water.
     
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  5. Aqueous Id flat Earth skeptic Valued Senior Member

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    Yes that's where I was heading. If there was some natural resource readily available that could contain steam, then you get potable water, hot water, a way to sterilize plus power. For most folks, that would be most practical as electricity. But for the people in crisis (think Darfur, only with access to the sea) even mechanical power might be the difference between life and death. For example suppose some of these were set up to pump the salt water, or to liberate people from hauling water generally, which steals their vital energy. Clay came to mind since pottery seems to be so basic. Obviously firing a pressure vessel or trying to make reliable clay pipe might get too complicated but nevertheless it came to mind as something that might be made plausible with a kit of some kind, maybe with some simple tools and templates to make forms from. Something like that. Once you give people the way to bootstrap themselves out of abject misery they're going to exploit it and do everything in their power not to slide back. At least that's my thinking.
     
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  7. KilljoyKlown Whatever Valued Senior Member

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    Are you saying that cheep clean water will eliminate abject misery? I would say it might be a good start but still a long way from that goal.
     
  8. Trippy ALEA IACTA EST Staff Member

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    It's been a dream/idea of mine for sometime, the biggest technical stumbling block I keep coming back to is how to handle hot brine as a working fluid.

    It's a slight variation on another idea that I have that would produce potable water, crude oil, and maybe some useful minerals or metals.
     
  9. Aqueous Id flat Earth skeptic Valued Senior Member

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    I haven't tried it with sea water but I've played around a little with electrolysis. It would be interesting to have a cheap simple device that could provide some useful chemicals. In the case of people in crisis, even bleach might prevent a lot of needless illness and death.. Of course that would require educating people on safe handling etc.

    Unfortunately electrolysis is an electricity hog.

    Crude oil from sea water?
     
  10. Trippy ALEA IACTA EST Staff Member

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    Not directly, no.

    North Pacific Gyre + Thermal Depolymerization (and I've said too much already (; )
     
  11. billvon Valued Senior Member

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    Not directly. But combine it with carbon (from atmospheric CO2) and you can make almost any hydrocarbon you want.
     
  12. Trippy ALEA IACTA EST Staff Member

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    Another plan I have considered, but not what I was specifically thinking of.
     
  13. Fraggle Rocker Staff Member

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    Which neatly circles back to a point I have stressed repeatedly on this website: The vast majority of the people on this planet who lack what we Westerners consider basic human rights (which include not only the resources necessary for life but also dignity and a measure of freedom) lack these things not because of our greed or indifference, but because their own leaders are incompetent at best and despotic at worst.

    I've often used hunger as a bellwether, since the vast, sparsely populated nations of the Western Hemisphere can easily grow enough food to feed two planets. We in fact send boatloads of it to the Third World every year, where it is immediately confiscated by said despotic leaders, sold on the black market, and the proceeds used to buy Swiss villas and weapons to make war on the hapless downtrodden peasants in the next country over.

    With governments like that, it's almost impossible for the citizens to improve their own lives, and almost as impossible for us outsiders to help.
    Consider that infant mortality is a major cause of abject misery in the Third World. It may not be quite at the Stone Age-through-19th Century level of 80%, but it's still up in the 30's in many countries. Imagine having one of every three children in your community die before reaching puberty!

    Out of all the people I've known in 68 years, only one suffered through the death of a child, and that "child" was 19. It still brings tears to my eyes just to write this! I cannot imagine living in a world in which that is a routine event that happens to the majority of families.

    Dysentery is the leading cause of death among children in many of the poorest countries, and clean water is almost 100% effective as a preventative. So yes, clean water will make a quantum improvement in the elimination of "abject misery," even if it will not completely eradicate it.

    Remember Maslow's Hierarchy: Step 1 is survival. If you don't have that, everything else is just a dream.
     
  14. KilljoyKlown Whatever Valued Senior Member

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    I can relate to this. My younger brother was killed in Vietnam when he was 19 and it devastated my parents for over a year (very slow recovery).

    Well I did say it was a good start and I'll still stick with that. With more survivors you actually increase the number of people that will be in "abject misery" in many places on this Earth.

    I sometimes wonder if survival is enough? I know part of that problem is I am used to the standard of living I have, and I'm just not willing to survive at levels much lower than I'm used to. That's got to be someone else's job if it comes right down to it.

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  15. kwhilborn Banned Banned

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    Ion Concentration Polarization - ICP

    A new method for desalination has not been mentioned on this thread but it has been around for many years now.

    This is not typically as cost effective as osmosis methods, but operates at the microscopic scale so tiny gravity driven, battery operated desalination units are possible. Desalination typically requires pressurized tanks and is associated with giant structures.

    There are claims that this can be/is the new cheapest method of desalination and is very unique compared to traditional methods.

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    http://www.science20.com/news_articles/water_desalination_ion_concentration_polarization

    http://www.nature.com/nnano/journal/v5/n4/abs/nnano.2010.34.html

    http://www.rle.mit.edu/micronano/ICP_desalination.htm
     
    Last edited: Jun 1, 2012
  16. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    US farm subsidies, the vast fertile mid west, and well meaning groups all actually make life worse in many places in Africa, where locals could grow more food than the population needs. Why don´t they? you may ask.

    Answer is that the boat loads of food US (and some others) send is not all eaten by the leaders, but sold at prices in local markets which are less than the cost of local production, so even those with land to farm do not, but buy the cheaper food from America (or starve). That is less costly to them than raising their own, which they can not sell at a positive return. Many economies in Africa would be self sustaining if cheap food from America were not allowed into those African countries.

    If US really wanted to help, send agricultural experts, seeds for that climate, etc. as China is doing. It is little wonder China is winning the battle for the hearts and minds of Africa, with trade now more than the US has, many oil and mineral rights granted, etc. Rural Africans may not be educated, but they know US dumping of its food surpluses is why they can not make a living as farmers. If they don´t yet, there are plenty of Chinese communist agents telling them. China has more than one million Chinese workers in Africa! The RMB is starting be be used, but the dollar is still dominate - but for how long?
     
    Last edited by a moderator: Jun 1, 2012
  17. Saint Valued Senior Member

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    Is desalinated water free from heavy metals and other undesired elements?
     
  18. KilljoyKlown Whatever Valued Senior Member

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    It's so pure it's actually bad for you, they have to remineralize it for safe drinking.
     
  19. Read-Only Valued Senior Member

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    Minor correction: It's not that it's bad for you, it's to make it taste better / more like "normal" water (otherwise it tastes very flat). It's often aerated also - for the same reason.
     
  20. Asguard Kiss my dark side Valued Senior Member

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    Actually it can kill you if you drink to much without adding salts or eating a lot of salt. Obviously it depends on circumstances for instance someone in a desert country with a larger water intake is at more risk of water toxicity than someone in a colder country but the risk is there
     
  21. KilljoyKlown Whatever Valued Senior Member

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    I did some searching and couldn't find any support for what you just said. Do you have a link we can view in support of that?
     
  22. Neverfly Banned Banned

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    This is true. In fact, an event that made the news sometime back was "Hold your pee for a wii" contest a radio station held, that resulted in a woman's death from water intoxication.
     
  23. KilljoyKlown Whatever Valued Senior Member

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    I just read somewhere that it was impossible to hold it back long enough to cause death by water intoxication. When you got to go, you got to go. Anyway I know I couldn't do it.

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