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    • CommentAuthorKosmopolit
    • CommentTimeNov 23rd 2009
     (7277.1)
    So if you can generate power from the osmotic potential between fresh and salt water, couldn't you also generate power from the osmotic pressure between piss and fresh water (or grey water)?

    http://www.physorg.com/news178183113.html

    Taking a step further in the planet's hunt for clean power, Norway is to unveil on Tuesday the world's first prototype of an osmotic power plant on the banks of the Oslo fjord.

    The project is small-scale but could prove the great potential of osmotic energy.

    "It is a form of renewable energy which, unlike solar or wind power, produces a predictable and stable amount of energy regardless of the weather," explained Stein Erik Skilhagen, in charge of the project at state-owned Statkraft, which specialises in renewable energies.

    Osmotic energy is based on the principle that nature is constantly seeking balance, and plays on the different concentration levels of liquids.

    When freshwater and seawater meet on either side of a membrane -- a thin layer that retains salt but lets water pass -- freshwater is drawn towards the seawater side. The flow puts pressure on the seawater side, and that pressure can be used to drive a turbine, producing electricity.
  1.  (7277.2)
    Generating power from piss?
    How very Vespasian of you.
    • CommentAuthorKosmopolit
    • CommentTimeNov 23rd 2009
     (7277.3)
    The lights won't smell any different.
    • CommentAuthorlead_pipe
    • CommentTimeNov 23rd 2009
     (7277.4)
    You could - in theory.

    In practise, it's easier to get megalitres of salt water than to aggregate megalitres of piss.

    Household sewerage is the only outflow that can't be used as grey water (because of the pathogens in your poo, I think). If you had a dry composting system and you did your Numba Twos separately from your Numba Ones, you might be able to use your urine colleciton. I don't know enough about the chemical make-up of urine. I think another problem could be the variance in people's wee - a household that was well-hydrated would probably excrete wee with a low salinity, and there would be a much smaller osmotic potential than if you used the piss of the guy that washed his whisky down with salty chips.
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      CommentAuthorbjacques
    • CommentTimeNov 24th 2009
     (7277.5)
    I've tried this with the gas tanks of several cars, but, based on observations from a safe distance, I don't think it helps any.