Basic chemical questions

Hi peeps!
I was hoping you could help me with some questions.

1) Can I store both used film developer and paper developer in the same tank, or do they require you to turn them in in separate containers?

2) Is stop bath harmless or should it be turned in for processing as well?

I'll add more questions as they surface. Thanks in advance!

-Ljus

If you mean for disposal, yes of course.

But unless you have a septic tank your develop can be put down the drain.

Ian

You don't say where you live, that will have a bearing on what local regulations you may have to abide by.
Here in England it is permissible to dispose of "amateur" quantities down the domestic drain.

Dave, I live in Sweden and I think I have to turn it in. In either case it's not going down the drain.

Ian, Yes, I mean for chemical waste disposal. So I can mix them then? Lovely.

Just to let you know what happens at licensed disposal sites:

They neutralise the developer by mixing with de-silvered fixer then it goes to drain. Same with colour chemistry. I worked in precious metal recovery for 20 years and that what our permits allowed.

Ian

Used fixer is the one you really need to dispose of as toxic waste as it will contain silver which is toxic to the micro-organisms used to process waste.

Developer is not toxic in that way. Paper and film developers contain essentially the same chemicals so you can mix them together without problem I'd have thought. I just flush it down the soil drain with lots of water but obviously if your local authorities require even non-commercial quantities of developer to be disposed of as toxic waste then that is what you will have to do.

Stop bath is just a weak acid (like vinegar) with possibly some indicator dye but will contain some carry-over from the developer so it is up to you if you think that makes it worth treating as toxic. You can add it to the waste developer too if you wish.

Bob.

Ian, that sounds pretty straight forward. What are the effects when mixed like you said? Is it any less toxic?

Bob, thanks for clarifying. Fixer was the only thing I was sure about.