Greetings, Process Engineer:

We have been in the phototooling business for nearly 13 years now.  When
we began, and until a bit more than a year ago when we moved to our new
building (which also houses a new PCB Facility), we handled our photographic
waste in much the same way you describe.

We did have a silver recovery system and sold the silver on a regular basis, 
however it never paid all that well.  We had our spent fix hauled (for which
we paid a hauler ... wish we could have been paid for those barrels) and
discharged all the water our processor used.

When we were preparing for our move, we decided to change our strategy to
discharge as little as possible and recover as much high quality silver as
possible.  In addition, we wanted to exceed the current limits.

Firstly, the national limit for silver discharge is 0.43/ppm (maximum daily)
and 0.24/ppm monthly average.  (40CFR433.14(a))  There are sometimes local
variations to this, but they generally don't vary too much. 

For the past year our lab results have consistantly run in the 0.015 to 0.025
range.  Our average daily discharge of all fluids have been 25 gallons.  We
have a Kodak 710 film processor which consumes 2 gpm when in operation.

Our system consists of the following components:

1.  All rinse water is recirculated through an Aqua Saver system which removes
residual silver through ion exchange, filters out particulates and adds a bio-
cyde to control 'bioslime' growth.  There is a little discharge from this system which is routed through the final two 5 gallon metallic exchange cartridges.

2.  The fixer is recirculated through a Byers silver recovery unit and returned
to the processor.  There is an amount that is 'spent' which, once it has been
desilvered, goes to a small metering station which feeds  into the trailing
metallic exchange cartridges.  This process is controlled by the makeup rate
we have established for our system.  The silver we harvest is metal grade, which
means that it is both non-hazardous (when dry) and worth a lot more money when
sold.

3.  The spent developer goes directly to the sample point.

The only 'hazardous' materials we have to handle are:
	1.  The 5 gallon metalic exchange cartridges (one about every 2
months).
	2.  The ion resin filters from the aqua saver (self contained filters
which are not much larger than the film processors filters)
	3.  The silver.

4.  This system does have a downside, however.  It requires that the operator(s)have a regular maintenance schedule (regular filter changes, maintenance of the
sample point and all tubing, monitoring of the silver concentration level of
the fixer and the plate out unit, etc).  

I would say that it has been our experience that this system has actaully
saved us time overall.  We no longer have to deal with the barrels -- both
their weight and mess *and* the fact they must be double contained because
they *do* spring leaks from time to time.  The lab is much tidier with only
the low profile system there -- along with some fresh chemistry, and a lot fewerindependent systems to fail (independently, as they do).

Our  water consumption has gone to near zero, making us the darling of the POTW!

I hope this helps.

-isaac

--------------
Isaac Stringer
KML Engineering Corp.
1609 Watson Court
Milpitas, CA 95035

(408) 942-9800

> Resent-Sender: [log in to unmask]
> 
> Hello fellow TechNetters:
> 
> In the development of Silver Halide film, there are byproducts of spent
> developer and fixer.  How do you handle these?  Or, more specifically...
> 
> I am told by some people, that depending upon the amount of silver in the
> developer, if it is within limits, can be sent down the drain with the rinse
> water.  A waste treatment lab tech suggested that it could be used to treat
> some of the waste they handle to adjust the pH.  Has anybody tried re-using
> spent developer for anything?  Currently, the developer is drained from the
> feed-and-bleed system of the Film Processor unit into a barrel, which is
> carried to our Waste Treatment department.
> 
> In addition, how do you handle the spent fixer solution?  It is usually
> heavily concentrated with silver.  Currently, it is drained from the
> feed-and-bleed system of the Processor unit into barrels, which are carried
> to Waste Treatment department, who sells the barrels.  We have looked into
> silver recovery units, but haven't found one we like (got any suggestions?).
>  
> 
> I'd like to eliminate the handling chemical waste by our Artwork Generation
> technicians.  How do most places handle the by-products of Silver Halide film
> development?
> 
> Thank you in advance.
> 
> Sincerely,
> 
>  Process Engineer
> 
> 
> 

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to:           *
* [log in to unmask] with <subject: unsubscribe> and no text.        *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************