desalination

Discussion in 'The big picture' started by lezstar, Nov 18, 2007.

  1. lezstar

    lezstar Junior Member

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    very interested to hear any thoughts people have on the whole lack of water issue and and best practice regarding future ways to produce fresh water ,eg desalination plants ,condensation capture etc,regards ,lez
     
  2. ppp

    ppp Junior Member

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    an average house with only modest rainfall has well over 120 000 litres of water fall on it. In SE Queensland, households are being told to aim for, and are meeting the target of 140L per person per day. This can be reduced even further.

    A couple will therefore use less than 2 x 365 x 140L per year = 102 000L

    The combination of this, and the existing Dams used for long term or deep storage, should go some way to solving the problem I think.
     
  3. Michaelangelica

    Michaelangelica Junior Member

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  4. gardenlen

    gardenlen Group for banned users

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    well desal' uses oodles of what is going to be expensive power at a time when we are being asked to trim our power usage and have special meters where they can turn off certain power use at will. plus the sight of desal' units along our beaches is not going to be a pretty sight. so far teh one at the gold coast is nothing but problematic and not ready for hand over yet!

    for us we don't think the people are doing enough to be water sufficient and use reticulated water as back up only.

    not many place the importance of water high enough above landscape and outside lifestyle(most of which probably ever gets used).

    we have a 22.5k/l tank this keeps us off the grid for most of the year, i look around and see many homes with tanks of minimum size to secure the rebate, small tanks may fill fast but when empty they are empty for a long time, many of these tanks are there for the look good and feel good aspect an the wate does nothing to reduce that home owners relyance on town water. it instead gets used to wash cars, driveways and water lawns and gardens when there are restriction on these activities.

    we use around 38 to 50 litres of water per day per person in this house so we see any allowance figure above say 100 litres a day (being generous) as encouraging waste, figure there are quiet a few people like us around who are using less than 100 litres per day per person, yet with the authorities say 140 litre per person usage they still reach that total usage city wide and oft' go over it, so there is a lot of wastage going on out there.

    water management practises in the broader community, are at best 4 minute showers and not flushing urine, that is not much of an effort, there is not much practise it would seem of using water at least twice, the simple act of using wash/machine and shower water to flush solids only saves a massive amount of water. but like all things practised sustainably water management can be inconvenient, and that is the fall down.

    i think the communities at large are looking for a more tangable reward for conserving water than simply managing it as it should be managed at the importance level it should be placed at, so for most homes a bare minimum tanks size would be 15k/l, and of course being somewhat sufficient with their own water.

    not going to drink recycled water ever.

    len
     
  5. Michaelangelica

    Michaelangelica Junior Member

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    I am intersted in a passive system.
    Igloo hothouses practically do this now. With a little tweeking i wonder how much fresh water you could make?
     
  6. WENewman

    WENewman Junior Member

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    Desalinization is an expensive and energy consuming process. Over 90% of fresh water is used by modern agriculture and industry; collectively, municipal golf courses use as much water as municipal human beings. So are we running out of water, or are people profiting from it. Water may become the next oil, and desalinization is just another way for profiteers to make money on something that they pollute and take from earth's inhabitants.
     
  7. Jana

    Jana Junior Member

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    Dr. Mae-Wan Ho

    https://www.i-sis.org.uk/SalineAgriculture.php
    Shortage of fresh water poses a much bigger threat to world food supply than the shortage of fossil fuels; cultivating salt-tolerant crops could solve both problems Dr. Mae-Wan Ho and Prof. Joe Cummins
     
  8. Michaelangelica

    Michaelangelica Junior Member

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    Yes, WENewman & lezstar i agree.
    however ;-
    Here, golf courses usually have their own sources of water, dams, bore or sewage. Reclaimed sewage water is being used by my council in a lot of sporting fields. Many too harvest water with rain tanks or lately dams as part of any new sporting complex design.
    Most water resources in Australia are owned by the Government (=people?) and I think they would cop a lot of flack if they sold them.

    Passive solar distillation has been used since Ancient Greek times to provide water on boats. It is not hugely energy hungry as is the osmosis system. Even this can be run cheaply. A local power station uses a lot of fresh water. now they have installed their own desal plant, running of base load power, they use sea water for cooling. I can't see why all coastal power stations could not do this, perhaps even on a larger scale.

    Even getting dam or river water to suburban homes uses energy, something often forgotten; mine travels probably 50K (100K in times of drought) before it gets to me. That is a lot of pumping. A lot of expensive pipes.

    Air water harvesting is another promising way of getting water without a lot of energy. This is a new concept and the small home jobs run on about 100W or so.

    Water tanks are a good idea but locally many people were being poisioned by agricultural spray drift that was running off the roofs into tanks.

    leztar I started a thread /discussion/blog on the looming water crisis here:-
    https://hypography.com/forums/earth-science/9628-water-where-will-it-come-2050-a.html
    it is something that concerns me too. Doubling the world's population in such a short time must lead to fresh water shortages. You probably can't have permculture without a secure water supply.
    PS
    Have a look at this
    https://www.seawatergreenhouse.com/
     
  9. teela

    teela Junior Member

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    De-sal is not the way to go.
    Every new house that is built should have it's own underground water tank of a decent size, this should be mandatory. We wouldn't even consider building a house without a toilet, and yet the most important thing of all (an independent water supply) is all too often left out....how crazy is that?
     
  10. Kardella

    Kardella Junior Member

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    Unfortunately, most governments (within Australia, both Federal and State) are more interested in 'big ticket' items that are marketable (such as desalination plants) rather than concentrating on approaches that will limit water usage and methods of recycling. Governments are also catering for the big end of town which draws on the lions share of fresh potable water.

    Rather than the potentially positive environmental impact of low technology solutions, we seem to be wedded to approaches that generate more greenhouse gases!
     
  11. Terra

    Terra Moderator

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    A Desal plant proposal is good for "calming the masses" when water restrictions are on govt can say we are working towards a solution , bad luck if it proves to be a useless white elephant pollies concerned are long gone or switched to a different portfolio by the time it comes online , imagine the riots if water stopped running out of taps , or if the pressure dropped off so you couldnt take a shower .
    Everyone must have decent size tanks if your in a area where pollution is a concern then use rainwater for toilet flush every bit helps . if i lived where i couldnt use rain water due to pollution i would be getting out fast .
    Terra
     
  12. springtide

    springtide Junior Member

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    There was a proposal in Perth to use a massive resevoir that had gone saline as a source of water and pressure head to run a de-sal plant (cheaply) - there was still the issue of the hypersaline effluent but i don't know why we have huge evaporation ponds to supply salt and chemicals in many parts of Australiabut they don't use de-sal effluent where half the work is done for them.

    Our methods of domestic water supply don't cater for local production and after the home insulation scandal i don't think any politician would want to encourage mass use of urban water tanks for drinking or dish washing... or anything much for that matter. - Not defending Peter G but it would only take a few dodgey plumbers to destroy your life - even a loose leaf screen on a tank could cause mosquito problems, dead possum in tank, etc - times a million tanks. I think any polly wether they be good or totally ineffectual would be an endangered species to go down that path.
     
  13. teela

    teela Junior Member

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    With the insulation grant it should've been done different...ie just giveaway the insulation and let us put it in ourselves........it's not rocket science after all. Same with plumbing up rainwater tanks...again not rocket science.
     

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