Printech Archive
Re: Insufficient COD reduction, Is sludge hazardous?

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From: Deb Jacobson (
Date: Thu Nov 18 1999 - 13:41:26 CST

Karen - I have a couple follow-up questions to Patricia's inquiry.

1) In reference to the physical/chemical treatment of the waste, please be
more specific about the process. Are they using a flocculent and allowing the
solids to settle out and then decanting the water? If so, what chemical are
they using? Are they mechanically mixing the waste and flocculent chemical to
facilitate bonding to the suspended solids? How long are they allowing the
solids to settle out?

Are they filtering the water after it is decanted off the settled out solids?
If yes, what type of filters? In terms of the coloration due to the pigment
and dye in the inks some color may remain in the filtered water, however the
water should come out relatively clear.

2) In regards to the sludge question - yes there is a sludge generated
comprised mostly of ink solids. It is typically non-hazardous solid waste in
most U.S. states. In terms of the toxicity due to metal content the metals
be reduced and some may replaced by re-blending the inks with alternative
products which replace the heavy metal. The alternative inks may cost more.
Barium and copper are commonly found in inks and there are few, if any,
replacements for these metals.

I can provide additional information on filters, chemical flocculent, etc.
based on Patricia's responses.

Deb Jacobson
At 10:53 AM 11/18/99 -0500, you wrote:
>Can anyone help Patricia, who works at a flexo plant in Brazil, with the
>following issues?
>1) In Brazil we've been handling some problems with flexo printers'
>treatment in facilities using water-based inks. The treatment currently used
>physical-chemical treatment, but it doesn't reduce completly the COD and
>parameters. The question is: what kind of treatment have you in the US been
>using for solving this problem?
>2) Using the treatment previously mencioned causes a sludge production after
>sedimentation. Do your systems produce that kind of sludge as well? Is it
>classified as hazardous due to the amount of metal components of inks?
>Thank you very much! All the information you could provide me would be really
Debra Jacobson (formerly Kramer)
E-mail Address (Revised 9/99)
IL Waste Management & Research Center / IL Dept of Natural Resources
1010 Jorie Boulevard, Suite 12
Oakbrook, IL 60523
630/472-5023 Fax

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