Brian Whatcott wrote in
:

Wandering around the local Hardware, I came across a sink/faucet
filter system billed as reverse osmosis. Cost is $200 operating
pressure 40 to 80 psi.
What's the scoop on this: can it handle salt water?
[it carries a warning to avoid water of unknown quality, unless pre
filtered with salt? - sounds doubtful ]

Thanks for insights


On Sat, 02 Sep 2006 22:08:04 -0400, Larry wrote:

To answer your question, if you put city water into any filter, even one
that uses toilet paper as a filtering agent, you'll get pure city water
out of it...

///
My latest batch from my distiller measures 2.1 ppm total dissolved
impurities. I think that comes from the collector pitcher being made of
polycarbonate plastic. At 4000 volts, as high as my hypot tester voltage
goes, two 6" long rods 2" apart only conducts 2.8 microamps....(c;

THAT's pure water.....for about 25c/gallon at 10c/KWH.

What I don't understand is we have this really HOT engine charging the
batteries that DOESN'T have a built in steam distiller making drinking
water. Pity.....

On Sat, 2 Sep 2006 15:43:11 -0400, "Glenn Ashmore"
wrote:

No. Domestic R/O systems are designed to take small amounts of minerals and
salts out of municipal water. They typically reduce the salt levels from
150 ppm to 5 or 6 ppm. Tapwater has an osmotic pressure around 10 PSI.
Tapwater R/O systems work on supply water pressure at 40 to 80 PSI (4 to 8
times the osmotic pressure) and recover from 25 to 50% of the flow. As the
total salts increase the osmotic pressure increases. The salt in seawater
averages 36,000 ppm and has an osmotic pressure around 376 PSI. Typically a
seawater R/O system operates between 700 and 850 PSI (2 to 2.5 times the
osmotic pressure) and recovers between 12 and 18% of the flow. Also the
membranes are a different material and constructed to handle the higher
pressures. Tapwater membranes can tolerate chlorine. Seawater membranes
can't.
---------------------------

Thanks to Larry and Glenn for those helpful replies
Pity!
The idea of pulling potable water out of the sea leaves only the
discovery of a viable method of pulling food out of air and water
in quantity, for real voyaging! :-)

Brian Whatcott Altus OK