Homebrew PCBs

----- Original Message ----- 
From: "Adam Seychell" <a_seychell@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, October 07, 2008 10:53 AM
Subject: Re: [Homebrew_PCBs] Re: Getting ready to switch from Ferric 
Chloride to ???????


> Stefan Trethan wrote:
>>
>> You can buy small commercial stations now that use ion exchangers for
>> treatment of rinsing water.
>>
>
> Traditionally, people precipitate the copper in large tanks and after
> the solids settle, it should be below about 5ppm and ready to dump. ion
> exchanges are only required when precipitation fails , for example,
> rinse waters containing chelators, which keep metal ions soluble.
>
> Are you sure the discharge limit in Europe is 0.5mg ?, That level is
> lower than what is considered safe to drink. Heck , some natural water
> supplies are higher than 0.5mg.

I found this in an official doc on water quality:

20. Copper - copper is normally only found in polluted waters, although 
trace amounts are sometimes found in soft moorland waters. Normally, copper 
is found as a result of corrosion from copper and copper containing alloys 
in plumbing systems.

As I said previously, there will be far more copper getting in the effluent 
from copper pipes than that in the the litre or so per year that I pour down 
the bog.

Leon