Keith, I talked with our chemist here.  He says DTC is the best thing 
around for getting rid of metals.  Lower limit on pH is 9.0, however.

Lou Hart


.

On Tue, 4 Jun 1996 [log in to unmask] wrote:

> 
> Dear Fine People:
> 
> The precipitant we use in our industrial wastewater treatment plant to remove
> chelated metals from our rinse waters is dithiocarbamate, or DTC.  DTC has
> the unfortunate ability to form the undesirable (read:  strictly regulated)
> byproduct/decomposition product CS2 (carbon disulfide), especially under
> acidic conditions.  Can anyone offer help in any of the following areas
> regarding this dilemma?
> 
> 1.  DTC management to minimize/eliminate CS2 formation?  Preventing DTC
> bearing waters from experiencing acidic conditions seems to be one of the
> more obvious interventions.
> 
> 2.  DTC variants which cannot form CS2 (if they exist)?
> 
> 3.  Alternatives to DTC?  We have tried several, none seems to match DTC's
> ability to precipitate a highly chelated, high lead bearing wastewater stream
> to under 0.2 ppm lead consistently.
> 
> 4.  Easy test kit/method for CS2?
> 
> Thanks for your help
> 
> Keith Perrin, 
> Compliance Specialist
> Printed Circuit Corp.
>