Chlorine removal - charcoal filter query
 

Hi,
Does anybody know if an activated charcoal filter removes chlorine
from fresh water such as that taken on board from municipal supplies

I read the following within an article in "Ocean Navigator" - online

"A charcoal filter is also required to prevent chlorine in water from
dockside sources getting to the membrane. It should be placed in the
system before the watermaker when tank water is used during
backflushing."

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Anybody know?

regards
Peter

Chlorine removal - charcoal filter query
 

On Jun 5, 2:12*pm, Herodotus wrote:

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Activated charcoal filters remove chemicals, including chlorine, by
adsorbing them onto sites on the surface of the charcoal. The number
of such sites on any one filter is limited, so the filter has a
limited life.

When using an AC filter to rid drinking water of chemicals causing
offensive tastes and smells, you'll know (by taste and smell) when to
change the filter.

For removing chlorine from town water such that the filtered water can
then be used to flush RO membranes, the story is more complicated.

Other than testing the level of free chlorine in the filtered water
(pool stores sell test kits for chlorine), I know of no way of testing
the effectiveness of an AC filter at removing chlorine. And I don't
know if an AC filter, stored dry, loses any of its adsorbed chlorine
(I suspect it must, but how much and how long it might take is unknown
to me).

The usual advice is to change the filter (some filters come with
advice about changing them every 3K litres/1K gallons, or every 6
months). AC filters are less expensive than RO membranes, so you
should err on the side of caution and just change the filter.

Cheers

Bil

Chlorine removal - charcoal filter query
 

On Wed, 4 Jun 2008 23:59:58 -0700 (PDT), Bil
wrote:

On Jun 5, 2:12*pm, Herodotus wrote:

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Activated charcoal filters remove chemicals, including chlorine, by
adsorbing them onto sites on the surface of the charcoal. The number
of such sites on any one filter is limited, so the filter has a
limited life.

When using an AC filter to rid drinking water of chemicals causing
offensive tastes and smells, you'll know (by taste and smell) when to
change the filter.

For removing chlorine from town water such that the filtered water can
then be used to flush RO membranes, the story is more complicated.

Other than testing the level of free chlorine in the filtered water
(pool stores sell test kits for chlorine), I know of no way of testing
the effectiveness of an AC filter at removing chlorine.
///
Bil

Useful looking response. About checking for chlorine, off the top, it
seems to me that a total dissolved solids - TDS meter which measures
water conductivity, would provide a fair indication. They can be
bought under $30.

Brian W

Chlorine removal - charcoal filter query
 

Brian Whatcott wrote in
:

On Wed, 4 Jun 2008 23:59:58 -0700 (PDT), Bil
wrote:

On Jun 5, 2:12*pm, Herodotus wrote:

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Activated charcoal filters remove chemicals, including chlorine, by
adsorbing them onto sites on the surface of the charcoal. The number
of such sites on any one filter is limited, so the filter has a
limited life.

When using an AC filter to rid drinking water of chemicals causing
offensive tastes and smells, you'll know (by taste and smell) when to
change the filter.

For removing chlorine from town water such that the filtered water can
then be used to flush RO membranes, the story is more complicated.

Other than testing the level of free chlorine in the filtered water
(pool stores sell test kits for chlorine), I know of no way of testing
the effectiveness of an AC filter at removing chlorine.
///
Bil

Useful looking response. About checking for chlorine, off the top, it
seems to me that a total dissolved solids - TDS meter which measures
water conductivity, would provide a fair indication. They can be
bought under $30.

Brian W

How would a TDS meter tell you if the water had chlorine or not? You have
no idea what the TDS of the water is. It might be interesting to compare
the TDS of the tank vs the TDS output of the water which has passed through
the carbon filter, but I'm not sure that would tell you much.

I use a carbon filter in the fresh water flush feed to my watermaker and
have had no problems.

-- Geoff
www.GeoffSchultz.org

Chlorine removal - charcoal filter query
 

Gotta agree with Geoff: a TDS meter is unlikely to tell you much about
chlorine. Pool test kits use either orthotolidine (called OTO in the
trade) or diethyl-p-phenylene diamine (DPD). I think DPD test kits are
more sensitive than OTO ones, but I'm unclear if pool test kits are
sensitive enough to pick up whatever level of chlorine that is in town
water and that is likely to damage an RO membrane.

AC filters definitely reduce chlorine in town water.

One secret to using an AC filter is to reduce the water pressure (ie
have a low flow rate through the AC filter). The idea being that the
longer the town water is in contact with the activated charcoal (AC),
the more likely the chlorine is to be adsorbed onto the surface of the
AC.

Bil

Chlorine removal - charcoal filter query
 

Peter,
You have received some pretty good responses to your query, but what
troubles me is your query. Please tell me you are NOT pumping the output of
your watermaker into your main water tank, because it very much sounds like
that is what you are doing. Please be aware that these watermakers fail and
that their failure can contaminate the output. It is always wise to use an
intermediate tank and then do a manual transfer after checking that the
generated water is OK.
Steve


"Herodotus" wrote in message
...
Hi,
Does anybody know if an activated charcoal filter removes chlorine
from fresh water such as that taken on board from municipal supplies

I read the following within an article in "Ocean Navigator" - online

"A charcoal filter is also required to prevent chlorine in water from
dockside sources getting to the membrane. It should be placed in the
system before the watermaker when tank water is used during
backflushing."

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Anybody know?

regards
Peter

Chlorine removal - charcoal filter query
 

Steve,

How are you claiming that watermakers fail? The only failures that I've
heard of are by cracking the membrane due to over pressurization or
sudden pressure change. In general they fail when someone hasn't
pickeled the system and then you don't get much output or the TDS is too
high. I've never heard of one failing during a production run.

I always check the TDS meter at the start of the run and at the end of
the run and I always see better TDS readings at the end. I pump
directly into my main (and only) tank and have never had any problems.


-- Geoff

"Steve Lusardi" wrote in
:

Peter,
You have received some pretty good responses to your query, but what
troubles me is your query. Please tell me you are NOT pumping the
output of your watermaker into your main water tank, because it very
much sounds like that is what you are doing. Please be aware that
these watermakers fail and that their failure can contaminate the
output. It is always wise to use an intermediate tank and then do a
manual transfer after checking that the generated water is OK.
Steve


"Herodotus" wrote in message
...
Hi,
Does anybody know if an activated charcoal filter removes chlorine
from fresh water such as that taken on board from municipal supplies

I read the following within an article in "Ocean Navigator" - online

"A charcoal filter is also required to prevent chlorine in water from
dockside sources getting to the membrane. It should be placed in the
system before the watermaker when tank water is used during
backflushing."

Further, I have had an activated charcoal filter for drinkable water
using the cartridge disposable household plumbing in-line filter for
years but have no idea as to how often one should change them.

Anybody know?

regards
Peter






--
-- Geoff
www.GeoffSchultz.org

Chlorine removal - charcoal filter query
 

On Thu, 05 Jun 2008 07:22:51 -0500, Geoff Schultz
wrote:


Activated charcoal filters remove chemicals, including chlorine, by
adsorbing them onto sites on the surface of the charcoal.
///
For removing chlorine from town water such that the filtered water can
then be used to flush RO membranes, the story is more complicated.

Other than testing the level of free chlorine in the filtered water
(pool stores sell test kits for chlorine), I know of no way of testing
the effectiveness of an AC filter at removing chlorine.
///
Bil

/// it
seems to me that a total dissolved solids - TDS meter which measures
water conductivity, would provide a fair indication. They can be
bought under $30.

Brian W

How would a TDS meter tell you if the water had chlorine or not?
///

-- Geoff
www.GeoffSchultz.org

No doubt, you would need to engage brain to draw useful conclusions
but I expect a value for total ionic salts would serve as a useful
proxy for the Cl ion concentration.

Brian W

Chlorine removal - charcoal filter query
 

Brian Whatcott wrote in
:

On Thu, 05 Jun 2008 07:22:51 -0500, Geoff Schultz
wrote:


Activated charcoal filters remove chemicals, including chlorine, by
adsorbing them onto sites on the surface of the charcoal.
///
For removing chlorine from town water such that the filtered water can
then be used to flush RO membranes, the story is more complicated.

Other than testing the level of free chlorine in the filtered water
(pool stores sell test kits for chlorine), I know of no way of testing
the effectiveness of an AC filter at removing chlorine.
///
Bil

/// it
seems to me that a total dissolved solids - TDS meter which measures
water conductivity, would provide a fair indication. They can be
bought under $30.

Brian W

How would a TDS meter tell you if the water had chlorine or not?
///

-- Geoff
www.GeoffSchultz.org

No doubt, you would need to engage brain to draw useful conclusions
but I expect a value for total ionic salts would serve as a useful
proxy for the Cl ion concentration.

Brian W

Brian,

Please explain further. I have a tank of RO water to which city water with
an unknown TDS has been added. How do I tell from the TDS reading how much
Cl (if any, as it may have evaporated) is present?

-- Geoff
www.GeoffSchultz.org

Chlorine removal - charcoal filter query
 

On Thu, 5 Jun 2008 15:13:13 +0200, "Steve Lusardi"
wrote:

Peter,
You have received some pretty good responses to your query, but what
troubles me is your query. Please tell me you are NOT pumping the output of
your watermaker into your main water tank, because it very much sounds like
that is what you are doing. Please be aware that these watermakers fail and
that their failure can contaminate the output. It is always wise to use an
intermediate tank and then do a manual transfer after checking that the
generated water is OK.
Steve


Hi Steve,

Yes, I am delighted with the informed responses. Thank you gentlemen.

I have only just installed the watermaker - a Katadyn 80E and as yet
have not used it as I was going to wait until I reached the Pacific
side of the Panama canal.

I have as yet not plumbed the freshwater output to a tank but had
intended to do so as I can't see myself filling up 20 litre jerry cans
and then lugging them up on deck to pour into the tank filler. I have
two main water tanks and at present I can't see how I can lead output
to an intermediate without all the lugging up the companionway or
installing an extra pump. Space is also an issue here.

cheers
Peter