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Original Paragraph:
[ Modified Mon Sep 20 16:51:28 EDT 2004
]
[ Modified Mon Sep 20 17:00:06 EDT 2004
]
[ Modified Fri Oct 29 02:10:48 EDT 2004
]
[ Modified Fri Oct 29 02:15:01 EDT 2004
]
[ Modified Mon Nov 15 14:48:11 EST 2004
]
[ Modified Mon Nov 15 15:00:28 EST 2004
]
Despite being in the middle of an ocean, obtaining and
retaining an adequate supply of fresh water is going to
require some careful thought and implementation. There will
be a continual loss of fresh water due to evaporation and
other factors, so fresh water needs to be replenished. There
are several possibilities for water replenishment -- rain water
collection, distilling sea water into fresh water, reverse
osmosis of sea water into fresh water, and importing fresh
water. Of these, importing fresh water seems the least
practical and rain water collection seems the most
practical.
Source: http://seastead.org/commented/paper/infra.html#Despite_being_in_the_middle_of_an_ocean_obtaining_
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Comments:
[Thu Nov 13 22:06:32 PST 2003-316] joel (NOSPAMjdgrov@yahoo.com.NOSPAM):
You need to add water reuse as one of the water replenishment pathways. Grey water waste stream can be routed to toilets (altho I would think you would lean towards a vacuum sewerage system or the like), irrigation, etc. Could also be processed and used for non-potable applications like clothes washing, bathing, etc.
[Mon Nov 17 16:01:51 PST 2003-320] corwyn (NOSPAMcorwyn@midcoast.com.NOSPAM):
If you are using water for your toilets, you WILL have a problem with water. But why would you? That human manure is going to be need to add nutrients back to the food production systems. Mix the feces and urine with dried plant material, let it compost and put it back on the garden. Simple, no tech. no energy expended.
The fresh water goes to humans for drinking, the really dirty to plants, everything else is inbetween.
As to how to get it, Solar panels to run reverse osmosis, or distilling is going to be hugely expensive (both in terms of PV panels needed and space in the sun for them. What you want is a solar water distiller, small plastic versions are available, you need a huge one, or lots of little ones.
Remember that PV is only 10-15% efficient. If it doesn't need to be run with electricity, do it some other way.
[Mon Nov 17 16:21:08 PST 2003-320] corwyn (NOSPAMcorwyn@midcoast.com.NOSPAM):
If you are using water for your toilets, you WILL have a problem with water. But why would you? That human manure is going to be need to add nutrients back to the food production systems. Mix the feces and urine with dried plant material, let it compost and put it back on the garden. Simple, no tech. no energy expended.
The fresh water goes to humans for drinking, the really dirty to plants, everything else is inbetween.
As to how to get it, Solar panels to run reverse osmosis, or distilling is going to be hugely expensive (both in terms of PV panels needed and space in the sun for them. What you want is a solar water distiller, small plastic versions are available, you need a huge one, or lots of little ones.
Remember that PV is only 10-15% efficient. If it doesn't need to be run with electricity, do it some other way.
[Tue Nov 18 12:15:32 PST 2003-321] Patri Friedman (NOSPAMpatri@seastead.org.NOSPAM):
I agree with much of this. We plan to use human waste as nutrients, and we don't plan to use water to flush toilets.
You seem to assume that all energy comes from PV panels, which as you say are inefficient. But wind turbines are likely to provide a substantial amount of our power.
Composting feces needs to be done with some care to avoid retransmitting pathogens/parasites. It also takes space and time. Its an OK method, but we personally prefer incineration.
The "Solar Distillation" that we talk about in the paper is identical to the "solar water distiller" that you talk about. We are talking about exactly the same thing. If you have a reference for making them more cheaply than our references say, we'd be interested in hearing it.
[Thu Feb 12 01:11:40 PST 2004-42] Justin Corwin (NOSPAMthesweetestdream@hotmail.com.NOSPAM):
some of these problems have been solved by earthship designers using specialty composting/chemical toilets and small-scale water treatment.
[Sat Feb 14 18:48:11 PST 2004-44] Stephan Jerde (NOSPAMskmsjerde@softhome.net.NOSPAM):
You might want to check out the work of Octave Levenspiel up at U of Oregon. He did a lot of work with respect to RO, in particular, placing an osmotic membrane at the bottom of a long tube. He figured out the length of the tube required such that the fresh water in the tube displaced enough seawater to provide the required pressure to keep the RO filter running. You essentially had a very deep cistern.
In this case, as you would pump water out of the cistern, the whole platform rise slightly because of loss of mass within the tube, but the increased pressure would force more water through the membrane, rapidly bringing it back into equilibrium.
The fixed cost and dynamics of the situation might be such that someone might want to build one and offer fresh water to his neighbors. It might actually be only cost effective as the basis for a "government" of sorts.
Anyway, it might be worth checking out.
Interesting idea.
[Fri Apr 2 04:27:38 PST 2004-92] Peter:
A great source of fresh water may be an iceberg tethered to the seasted. I am not sure how big a problem of getting the iceberg there will be, it would require some calculations. Some insulation may be necessary, but possibly not. This needs to be calculated too.
[Fri Apr 2 04:36:41 PST 2004-92] Peter:
A Google search
http://www.google.co.uk/search?q=iceberg+source+of+fresh+water&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search&meta=
came up with this
http://perc.ca/PEN/1993-06/holmes.html
and others. Take a look.
[Tue Sep 21 23:20:37 EDT 2004-264] OCTAVIAN:
DUUUUUUUUUUUUUDS!!!!NOBADY AT SEA USES FRESH WATER TO FLASH THE TOILET,...ITS SEA WATER.AND AGAIN,....WATERMAKERS:-)
[Sun Dec 19 15:32:58 EST 2004-353] Patri Friedman:
testing
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