At my previous position I ( it means my company ) payed 30k$ for such
lesson.We had RO system with tubes sensitive to oxidizing stuff.We installed
two independent sulfide injection system based on ORP control,each design to
treat up to 250% of normal levels of chlorine.One day,for short period,the
city sent high chlorine supply water.It smells ugly and took short time to
turn 24 RO elements into pieces od plastic inserts.The hit was so
strong,that I am no sure that carbon columns could help.
Edward



Edward Szpruch
Eltek , Manager of Process Engineering
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel  ++972 3 9395050 , Fax  ++972 3 9309581
e-mail   [log in to unmask]

> -----Original Message-----
> From: Alain Savard [SMTP:[log in to unmask]]
> Sent: ב אוקטובר 18 1999 21:29
> To:   [log in to unmask]
> Subject:      Re: [TN] Deionized water...
> 
> We used carbon filtering for a few reason: Chlorine, bacteria, algea,
> potential
> pesticides or other organic residues, and who knows when the city might
> decides
> to change a pipe and not bother to tell anyone (of course, the city can
> always be
> thrusted).
> 
> Alain Savard, B.Sc.
> Chemical Process Analyst
> CAE Electronics Ltd.
> e-mail: [log in to unmask]
> 
> -----Original Message-----
> From: Stephen R. Gregory [mailto:[log in to unmask]]
> Hi ya'll!
> I gotta question, do any of you that deionize city water for your
> cleaners,
> have a carbon bed before your cation, anion. and/or mixed beds? Now I'm
> not
> talking about a closed-loop Ion exchange filtering system, just straight
> water deionization.
> Well, I discovered that we do (for now anyway). I called the vendor that
> services us (I'm tempted to say who it is, and they're big. Because I
> think
> they've been ripping my employer off), and asked why there is a carbon bed
> in
> front of the other beds.
> Because from my understanding and experience the only reason you need a
> carbon bed is to filter out and remove the heavy metals and organic
> contaminates before they got to your cation and anion beds if you're
> closed-loop. I could always tell when my carbon beds were getting full,
> (or
> they weren't getting back-washed daily) when I started foaming in my
> cleaners.
> 
> Anyways, the guy said that the carbon beds will somehow extend the life
> the
> ion exchange resins by filtering the chlorine contained in city
> water...which
> I tend to question. When I was out in California (which has some of the
> hardest, most chlorinated water in the country) never was there a Carbon
> bed
> used before the ion exchange columns for my D.I. water, and this was the
> same
> company that serviced me in California as well. Was he tap dancing, or was
> there some truth to his logic?
> 
> I think the real reason is because a 3.6 cu. ft canister of either Cation
> or
> Anion beads are $97.50 ea., while a 3.6 cu. ft. canister of Carbon is $200
> ea...and nobody here ever questioned it.
> 
> -Steve Gregory-
> 
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