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

Brian Whatcott Altus OK

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.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Brian Whatcott" wrote in message
...


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

Brian Whatcott Altus OK

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


Of course it can. Buy a Brita filter, which says it filters out
everything except distilled water, pump the holding tank into the top of
it and you get fresh, pure drinking water for only $20 from Wally
World.....

Our city is recycling sewage through a whole roomful of Brita filters and
feeding it back into our faucets. The water comes out with only 3 ppb
impurities, better than my distiller!

C: SARCASM OFF

C:

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...

If the city water contains dissolved acids, salts (like NaCl) or any
other really tiny molecules, they'll flow right on through, maybe bumping
a fiber or two as they all flow between them. If there's **** in the
city water, it'll filter that out, but not the toxins from it which are
also too tiny to "filter".

Even REAL RO filters don't filter out ANYTHING that's smaller than the
holes in the membranes, something they don't like to talk about.
Recently, many RO operators got sick from biologic toxins released by the
bacteria that were piled up against the filtering membrane, broke down,
and released toxins that were too small to filter.

RO is just a fine filter, you know.....smaller than NaCl, it seems.

Pure water comes from DISTILLATION, not filtration. Even distillation
isn't "pure". If the water contains impurities that will distill, like
benzene that's in all water, you must STILL filter out the benzene and
other distillates from the output of the distiller. Luckily, these
distillates are all carbon based and are easily attached to activated
carbon, permanently. All distillers, including mine, have an activated
carbon filter to suck out the distillates. If you buy distilled water
from a grocery store in the water department, it will taste "metallic"
when you drink it from the distillates. If you buy Dasani, or one of the
other distilled water drinks, it's been filtered by carbon and the
metallic taste of the distillates is gone.

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.....

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.

"Glenn Ashmore" wrote in news:d9lKg.39748$ok5.37927
@dukeread01:

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.

Which is what rips the bacteria pushed up against the membrane apart,
releasing their toxins into the output stream through the membrane.

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.

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

Brian Whatcott wrote in
:

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! :-)



A large waterproof plastic sheet works very nicely in rainstorms not
associated with violent weather. Canvas gives it a funny taste from the
oils in the canvas. A cheap blue plastic tarp from Walmart is great....of
course, unless the "professional mariners" on the dock find out where you
bought it.....(c;

It rains a lot at sea, when I'm aboard, usually when I'm on watch! I take
it as "a sign"....



--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.