Tue, 28 Oct 1997 11:18:10 +1200

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Hi

i work at PCB shop in New Zealand and i am looking at waste treatment options and water savings for the whole factory.

By now i am totally confused :-), there are so many options and possibilities to create a total waste treatment system.

i would like to hear what other people are doing in way of water reduction and waste treament. We are looking at a number of different things such as water cooler for recirculation of cooling water, different plating cells and RO/ion exchange systems for recirculation of rinse waters. It is just very hard to determine what is the best way of doing it so i would love to talk to all of you guys who are already involved in this to figure out what direction we should be heading. There must be a lot of peopleout there doing a lot more than we are here in New Zealand. Our environmental laws are not that strict yet as in other parts of the world but they are definatly on the way and we want to be ahead of the requirements. So please guys help me out here with some ideas and what you are doing. I'll be most grateful.

Many kind regards Marie Holmgard

RSedlak@AOL.COM
Tue, 28 Oct 1997 11:24:14 -0500

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Marie:

We do not supply anything in waste treatment, but as a chemistry supplier, we are intimately involved in the issue. I advise you that the BEST thing that you can do to ease the issue, and cut costs is to separate your wastes, and treat them in different ways.

The presumption is that the only issues that you have in your waste water are pH and dissolved heavy metals.

Most of the time you can separate your waste streams into the following categories:

  1. Chelated, low, to neglible metal (rinses from resist strippers, alkaline cleaners, etc.)
  2. Chelated, high metal, (Electroless Copper rinse, and bailout, ammoniacal etch rinse)
  3. Non-Chelated, high metal (microetch rinse, electrolytic plating rinse, etc.)
On the first category, simple pH adjustment may be all that is required, do this, and put it down the drain, if the metal is low enough, do not allow the chelates to mix with category three, or you jack the cost of treatment to the sky.

Category three can best be treated by pH adjustment, and precipitation of metal sludge. Cheap and simple.

Category two is the big expense, and if you mix all your wastes, all the waste becomes category two waste. This must be treated by ion exchange, or precipitation with special chemicals, like sulfides, or weird expensive organics, to remove the metals from the chelates.

This is pretty general stuff, but it is very often overlooked as a powerful tool to assist and cut costs in waste treatment.

If I can be of more assistance, contact me off line.

Incidently, if you want to send me your fax number, I have an article on chelates and waste treatment that you might find interesting.

Best regards,

Rudy Sedlak
RD Chemical Company

HIHAT44@AOL.COM
Tue, 28 Oct 1997 11:54:40 -0500

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Marie, The environmental laws in California are most definitely strict. It is not out of the ordinary to see limits of copper discharge as low as .4ppm. As the laws have become more and more strict the PCB manufactures have been able to stay in compliance. Surprisingly many PCB shops have found themselves not only saving money and reducing waste in the process, but also streamlining their waste treat systems. If you would like some information on the systems and types of chemicals used feel free to contact me anytime.

Stephen M. Wentz
Florida
CirTech Inc.

VM#(408)233-0443
PH#(408)996-2959

fgolisan (fgolisan@HADCO.COM)
Tue, 28 Oct 1997 11:40:29 PST

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Marie,

If you are truly interested in getting into this subject as a active project. You will need to start with a detailed listing of all processes you intend to operate in your plant. In addition you will need a to develop a complete listing of process specifications with types and levels of contamination expected in each waste stream. Another major hurdle is what possible uses that you have within your plant for recycled water etc. You will need to establish minimum water quality standards for your recovered water. This information may then be used to develop a comprehensive treatment plan and define processes to be used. A process that is cost effective for 10,000 gal/week may not even be worth considering at a rate of 100 gal/week. The last project of this type I did was a @250 GPM Copper and @65 GPM Sn/Pb rinse water system. With installation and startup it took nearly 19 months the complete. The survey was repeated just prior to startup and all water samples where checked to prevent contamination due to process changes.

I wish you the best of luck on this one!

Fred Golisano

HYPERLINK mailto:Fgolisan@Hadco.com Fgolisan@Hadco.com