What you just wrote triggered a memory (it has been a long time since I used
Ferric Chloride as an etchant). The label says "Discard the UNUSED
solution........."  (I wasn't Shouting just Highlighting).  Used solution
contains high levels of Copper and as John Gardner pointed out earlier
Copper is highly toxic to a lot of marine (and freshwater) life. It is that
copper which is the main problem not the acidity or otherwise of the
solution. I believe you will find that Copper Salts are present in a lot of
plant control products (or used to be before being banned). Copper salts are
also used to treat wood to prevent bacterial decay. I don't think that the
sewerage works would thank you for killing off their bacteria. That would
drop them right in the s***

What does your Federal and State Legislation say about disposal of
pollutants etc.?

Regards

Chris


> First let me say, I'm new at this and only doing it as a hobby.
>
> Reading the instructions on the back of my 16oz bottle of "PCB Etchant
> Solution" (Ferric Chloride) from Radio Shack.
> The last line reads: "Discard unused solution into toilet bowl and flush"
>
> I prefer to reuse it a few times before discarding, it does loose its
> strength requiring longer time to etch.
>
> I agree with Roman, drain cleaners and even household cleaners, etc.. are
> more harmful if for no other reason the concentration.  If your household
> waste is NOT sent to a treatment plant (i.e. septic system or nothing at
> all) then you should be concerned with the volume and type of other
> household chemicals besides the odd few ounces of etchant solution.
>
> Malcolm
> ----- Original Message -----
> From: Roman Black <fastvid@EZY.NET.AU>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Friday, March 23, 2001 12:48 AM
> Subject: Re: [OT] Disposal of used PCB fabrication chemicals
>
>
> > Chris Carr wrote:
> >
> > > By putting it in sealed containers and calling an authorised waste
> disposal
> > > company.
> > >
> > > >I just want to make sure the drainage pipes in my or the
> > > > neighbours' houses won't get harm!
> > > >
> > >
> > > Of course the Sewerage Plant and the Environment into which these
> chemicals
> > > are discharged does not matter.
> > >
> > > My advise is always dispose of chemicals properly and that invariably
> means
> > > never down the sewerage system.
> >
> >
> > Umm, just a thought, isn't "Draino" and other sink/drain
> > cleaners more corrosive than the usual pcb etchants?
> > Sure burns your hands more. Once you dilute it a few
> > times with a little tapwater it is less corrosive than
> > say lemon juice or vinegar. An acid or alkali is not
> > as bad as other toxic substances.
> > -Roman
> >
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> >
> >
>
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>

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