From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Wed Jan 23 2002 - 06:39:58 MST
On Wed, 23 Jan 2002, Chen Yixiong, Eric wrote:
> The second water agreement will run out in 2061, and so Singapore
> currently attempts to negotiate another new agreement.
Very silly. If we aren't well into the nanotech era by 2061
(when desalination gets *much* cheaper) then we are going to
have much larger problems than water sources.
> The problem definitely does not lie with insufficient water but with
> relatively expensive energy.
Not completely -- one can have better technology for removing salt
from water. I believe the DOE or Dept. of Defense are actively
soliciting such proposals. I know Israel is working in this area.
> reverse osmosis or other methods to extract water from the oceans.
I believe this is currently the least expensive method.
> A possible energy source that many people had neglected
> might lie with storm lighting,
Thats a pretty unreliable source. Better would be normal solar
energy. Singapore has plenty of that. Or they can easily lease
some from the Australians. If we can move oil around the world
we can certainly move water.
> Without technical expertise, I hesitate to suggest using a scaled up
> version of an electrosis system that can mass convert water into its
> component hydrogen and oxygen as a lighting strike passes through it.
While producing hydrogen from water is certainly the way to go in
the long term, I don't think lightening should be used as the energy
source.
For fresh water, there are two ways to go. First would be to
use the existing sodium and chloride pumps found in cells to pump
the salt (and potentially other ions using other pumps) out of the
water. I suspect the energy costs of supplying ATP to molecular
pumps would be lower than the energy costs of reverse osmosis.
What one has to master is the assembly of think lipid bilayers,
the insertion of the protein pumps into the bilayers and the
manufacture of devices that can contain a large surface area
for the assembled lipid/protein structures.
In the more distant future, one will use molecular sorters.
See Chapter 13, pages 373-386 in Nanosystems. Using these
I expect the costs would be even cheaper.
There is a paper that needs to be written here comparing
current and future water purification costs.
Robert
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