Used Chemicals.

Just wondering if there might be a better method of disposing of my chemicals besides down the drain? The solution would have to be practical as well as economical.
Cheers,
Mike

Developer... down the drain

Stop... down the drain

Fixer, collect in a 5 gallon can, dump some steel wool at the bottom and agitate every so often. After a couple of days.... down the drain! The steel wool can go to solid disposal.
[But I found my ladlord dumps a silver solution in the drains to keep tree-roots from growing]

PS. you can put the spent selenium toner in a flower bed.... nice pink/purple flowers.
Roses and tulips love it

Dear Mike,

Most of the chemicals are pretty benign, particularly developer and stop. According to a Kodak publication on disposal, once silver is removed from spent fixer, all three can be handled by public sewage treatment systems. Check out http://silverprofitphoto.com/products/index.htm. I don't know if the product is available in Canada. In the U.S. Porter's is the usual source.

Neal Wydra

Hi Mike

There was a pretty extensive debate, on spent chemicals a while back. I notice you are Canadian, here in Toronto there is very strict rules on what can be put down the drain, I would think the rules would apply to your area.
I do dump the developer and stop at the same time , and I use a silver recovery machine for the fix. The selenium is kept in separate containers and the company that maintains the recovery unit takes the selenium once every 6months.
We had a city spot inspection team show up at our shop and took samples at the floor drain leading out of our darkrooms , to check the efficiency of our system. If we had not passed we would be forced to bottle all chemicals and fix the recovery system before operating again.
I would ask the local water waste management group in your area for their thoughts on what can go down the drain from your darkroom.

What about those of us who have a septic system? I've heard that too much chemistry going down the drain can kill off the micro-organisms in the tank that break down waste (not good). If I'm feeling lazy I just dump it but I've been trying to at least bottle up the fixer.

Bob Carnie said:

Hi Mike

I would ask the local water waste management group in your area for their thoughts on what can go down the drain from your darkroom.

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I would be reluctant to ask for trouble. The authorities might find that question a very good reason to test your drains.

We have a septic tank here at home. The local university allows me to dump my spent fixer in their recovery unit. It doesn’t amount to any real money for them, but it does help the environment, and they approve of that.

John

Hi John

You could be right about asking for trouble, but , in my situation I need to dispose of 8-16 litres of spent fix a day, depending upon my work load. As well I did not ask to be checked they showed up unannounced with test bottles in hand. ( my lab has been in complience with local standards from the day I was aware of these issues)
If someone is using a home darkroom and using small trays , the collection method you suggest is good, in fact APUGers and others in this town use my silver recovery at no cost and all are welcome to take advantage of it.
I just know that doing a large show for example , even if done at home will use a lot of spent fix, and if there is copper drains, watch out .
I would prefer to be in compliance as I have no choice, and any worker in our craft should also be in compliance to the local requirements.
Any lab worth their salt will take used fix for no fee and the home worker should feel compelled to do so.

This is going to vary a lot by region. In my locality near San Francisco, the local city has a blanket 1 part per million limit on most metals in solution. That's around the detection limit on something like an atomic absorbtion spectrometer, so I think it is a pragmatic number (!). The county does have a hazardous waste drop every month that will handle photographic chemicals.

I clean fixer using a small silver recovery kit. I don't expect to recover costs, just remove enough silver to make diluting the residue practical.

Selenium toner can be exhausted using fogged and developed paper, though I don't know of a reliable test for residual Se. That's best sent to the waste handlers.

The developer and stop neutralise themselves and go to normal drainage, or on the non-edible area of the garden in summer.

The real pain with stockpiling is finding suitable containers that don't cost more than the chemicals, plus correct labeling. I knew my early lab training would be useful!

What happens "and if there is copper drains, watch out." ?

fotch said:

What happens "and if there is copper drains, watch out." ?

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If you have a silver salt in solution, copper will replace the silver. The result will be a flock-like precipitate of extremely fine silver crystals, typically blackish gray, and erosion of the copper. When we did this experiment in high school chemistry (back in 1977, when silver nitrate was still permitted in high school chem labs), the copper wire used was visibly pitted in plating out a gram or two of silver from the solution. The damage would be less rapid with used fixer -- it carries less silver and is less reactive than the silver nitrate solution we used -- but might well be concentrated more by existing deposits in the drain pipe, resulting in pinhole leaks in the drain.

Fortunately, copper is rare in drains applications -- it's used for water service because it lasted better than anything else available before plastic pipe and still carries the prestige associated with its price, but for drains not associated with a chemical lab (which drains are often Pyrex type glass), the cheapest material that meets local codes has been the rule for decades. I'd be amazed if drains in any house built in North America in the past century or longer were made of anything more reactive than black iron pipe; all new construction I'm aware of now uses plastic for drains and, where permitted by codes, for supply as well.

Where you *could* run into a problem is with a brass tailpiece in an existing bathroom or kitchen sink. The zinc in the brass is more reactive than copper, and normally protects the copper, but zinc doesn't cross react with a lot of things that solubilize silver, like thiosulfate (zinc used to be used to line steel developing tanks, before the development of stainless steels). The result, over time, would be depletion of the copper from the brass and embrittlement as the metal changes from thin extruded or rolled/soldered brass to thin, porous, brittle zinc.

Daniel Lawton said:

What about those of us who have a septic system? I've heard that too much chemistry going down the drain can kill off the micro-organisms in the tank that break down waste (not good). If I'm feeling lazy I just dump it but I've been trying to at least bottle up the fixer.

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If you are a private photographer operating a home darkroom no septic system will be harmed or overwhelmed by the volume of photochemicals you would normally put through it. If you're a commercial photographer, then a septic system could be overwhelmed, and you would need to find other ways to dispose/neutralize your chemicals before putting them through the system.

If you're on city water/sewer, then follow the environmental guidelines for your area.

One of the reasons I began using phenidone/Vit. C developers is that they are non-toxic. Unless you're using a lot of high-strength selenium, you don't need to worry about it. I use it with my washing aid to increase print permanence, not for changing the print color, and this is at very dilutions. Fixer is the only part of the process that (depending on your volume and circumstances) may need special disposal handling. The steel wool trick is easy and cheap.


Larry