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Re: Home Plumbing Problem--not a structural related

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Dear Nels:

Its been a while since I took geochemistry, but I think CO2 applied under
pressure to water forms cabonic acid (H2CO3) which drops the Ph.  The
solubility of Calcium Carbonate is highly Ph dependant.  With a slightly
lower Ph, the deposits go into solution and since both Calcium and Carbonate
are non toxic, this is a clever solution in that the user can safetly
consume the problem.  The only thing to watch for is some pipes are held
together by the deposits and remocving them causes leaks.

John Schenne, PE

----- Original Message -----
From: <NRoselund(--nospam--at)aol.com>
To: <jschenne(--nospam--at)localnet.com>
Cc: <seaint(--nospam--at)seaint.org>
Sent: Monday, January 10, 2000 11:55 AM
Subject: Re: Home Plumbing Problem--not a structural related


> John,
>
> I haven't heard of the process, and it may do the job.  But it doesn't
seem
> plausible.  However, maybe I've something to learn here.
>
> I think the deposits in plumbing pipes are largely calcium carbonate
[CaCO3],
> the same substance as limestone, or the binder in lime mortar, or calcite,
> which is the natural binder in some sandstones.  The calcium in CaCO3 is
> fully reacted with CO2.  It is the reaction of CO2 with Water and hydrated
> lime [Ca(OH)2] that forms CaCO3, to develop the binder in lime mortar.
CaCO3
> is slightly soluble in water, and hard water carries a lot of it.  As
water
> stands in a pipe, some of the dissolved CaCO3 precipitates as deposits
that
> eventually clog the pipe.  I would assume the deposits in plumbing pipes
to
> be essentially inert to CO2.  Nevertheless, if the process works, I'd like
to
> know more about it.
>
> Nels Roselund
> Structural Engineer
>
>