Precipitate out majority of chemicals in C-41 waste?

surprise!

A
surprise!

  • Tel
  • Feb 7, 2023
  • 2
  • 3
  • 145
Anatomy

A
Anatomy

  • 1
  • 4
  • 167
Morning

D
Morning

  • 0
  • 0
  • 103
BD2023-1.jpg

D
BD2023-1.jpg

  • 0
  • 1
  • 127
BD2023-2.jpg

D
BD2023-2.jpg

  • 1
  • 0
  • 100

Recent Classifieds

Forum statistics

Threads
182,039
Messages
2,519,202
Members
95,479
Latest member
Drumfishie
Recent bookmarks
1

Kino

Subscriber
Joined
Jan 20, 2006
Messages
5,676
Location
not here
Shooter
Multi Format
Just an idle thought; Is there a reasonable way to precipitate out the vast majority of chemicals in C-41 (or any other color process) waste as a sludge?

Yes, it is an overly broad question, but I don't know how to ask it otherwise...
 

Mr Bill

Member
Joined
Aug 22, 2006
Messages
1,181
Shooter
Multi Format
Yes, I think that evaporation is about the only "sensible" way.

Is this really an effluent control question? In the 1980s and 1990s the photo industries did most of its research on how to make photoprocessing waste "acceptable" with respect to all of the regulations that came up about that time. The main issues with the photographic effluent, at least the mainstream processes, were "oxygen demand" (aka BOD and COD), the tendency to consume oxygen out of the water as various chemical components were degraded, and the silver content. The first one is readily handled by sewage treatment plants; the second is preferably done, to some arbitrary degree, by the photofinisher. I say arbitrary because once you get some silver in solution, via fixing, you pretty much cannot prevent some of this from getting into your wash water.

So one question is, how much silver is allowed to "escape" at the end of the line? What is basically happening is that the film emulsion is wet with fixer when you move it into the first wash bath, then it is wet with that when you move it into the next wash bath, etc. It's not unlike using a sponge to mop up some spilled coffee, then rinsing the sponge in a series of trays; the sponge (and water) gradually get more and more clean. At some point you finally say, well, I guess it's clean enough now.

Some of the important methods used by the photoprocessing business are based on both minimizing the total amount of waste, and in keeping it as concentrated in one place as much as possible. This is done by replenishing chemicals (you don't discard them if they are only "lightly used") and using multi-tank "counter-current flow" replenishment (this is loosely what you do with a 2-bath fixing system).

Too much info? Or is it going in the wrong direction?
 
OP
OP
Kino

Kino

Subscriber
Joined
Jan 20, 2006
Messages
5,676
Location
not here
Shooter
Multi Format
I have a septic system and my county has a very primitive hazmat collection system.
 

Ian Grant

Subscriber
Joined
Aug 2, 2004
Messages
22,352
Location
West Midland
Shooter
Multi Format
There are ways to do this using flocculation but it's 40+ years since I worked on it in the Carpet industry but it was being done with photo chemical wastes early 2000's in Belgium as their discharge requirements re severe.

Ian
 

Mr Bill

Member
Joined
Aug 22, 2006
Messages
1,181
Shooter
Multi Format
There are ways to do this using flocculation but it's 40+ years since I worked on it in the Carpet industry but it was being done with photo chemical wastes early 2000's in Belgium as their discharge requirements re severe.

Kodak developed a technology, maybe late 1980s, I'm guessing, using a chemical called "TMT," which would combine with the photo silver. Problem was, the precipitate was so fine that it didn't want to settle out, and it would tend to quickly clog the ultrafine filters needed. So they used some sort of a flocculant to deal with this. Commercial systems were built, but this is hardly a way to deal with small scale usage. I don't know of any other such uses in the industry.
 
OP
OP
Kino

Kino

Subscriber
Joined
Jan 20, 2006
Messages
5,676
Location
not here
Shooter
Multi Format
I have a plan to recover the silver using a self-built silver recovery system, but wanted to concentrate the chemistry to minimize any possible charges in case I must resort to commercial disposal of the waste.

I may be forced to evaporate the effluent down to powder.
 

Rudeofus

Subscriber
Joined
Aug 13, 2009
Messages
4,625
Location
EU
Shooter
Medium Format
The majority of components in C-41 color developer is Potassium or Sodium Carbonate. You can get rid of Carbonate, but it's very hard to precipitate out alkali metal ions. If you look at the C-41 formulas posted here, can you pin down which components may remain in your liquid waste, and which ones must be eliminated prior to dumping ?
 

mklw1954

Member
Joined
Dec 2, 2009
Messages
391
Location
Monroe, NY
Shooter
Medium Format
While this is for commercial/industrial size effluent treatment, is from 1976 and may be dated, and is a lot to go through, this USEPA development document might indicated which treatment technologies are considered to be effective and practical (e.g., filtration, chemical coagulation/precipitation, carbon adsorption, etc.). Obviously you would have to adapt them to very small scale.

It looks like you can advance the pages by entering page numbers on the lower left.

Yhttps://nepis.epa.gov/Exe/ZyNET.exe/2000JL74.txt?ZyActionD=ZyDocument&Client=EPA&Index=1976%20Thru%201980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZYFILES%5CINDEX%20DATA%5C76THRU80%5CTXT%5C00000004%5C2000JL74.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1
 

thuggins

Member
Joined
Jan 12, 2008
Messages
1,136
Location
Dallas, TX
Shooter
Multi Format
I have a plan to recover the silver using a self-built silver recovery system.

I did an estimate a while back and figured that an avid amateur (a roll or so a week) would take 10 years to accumulate one ounce of silver. I really hope that's not your retirement plan.
 
OP
OP
Kino

Kino

Subscriber
Joined
Jan 20, 2006
Messages
5,676
Location
not here
Shooter
Multi Format
I did an estimate a while back and figured that an avid amateur (a roll or so a week) would take 10 years to accumulate one ounce of silver. I really hope that's not your retirement plan.
Hardly. I just want to recover the sliver. Planned on plating some copper medallion for shits and grins. Might get one or two with a heavy coat in a few years....
 
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links.
To read our full affiliate disclosure statement please click Here.

PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Ilford ADOX Freestyle Photographic Stearman Press Weldon Color Lab Blue Moon Camera & Machine
Top Bottom