View Full Version : Disposing of Old Chemicals

29-Sep-2011, 12:40
I unfortunately took an extended break from my darkroom--lack of available time and a mouse infestation :eek: in my basement darkroom kept me away for much longer than I would have liked. As such I completely forgot about some chemicals I had mixed up and was storing in jugs. I'm finally getting back to developing/printing and need to clean my old jugs out. My question is: is the disposal the same for old chemicals? At this point they are at least a year old, possibly older (I know). I normally dump developer and stop bath down the work sink, but do these become more potent the longer they sit around? Same with fixer--I still have no idea how to properly dispose of it, old or new.

(For reference I live in a suburban neighborhood, no septic tank.)

29-Sep-2011, 12:52
Usually not a problem just dump down the sink. Stop bath is just a mild acid, developer oxides, fixer is the only real potentially harmful chemical but only in large quantities.

29-Sep-2011, 13:03
Be careful about dumping used fix down the drain. I've been told by our chemical disposal crew that there are sensors in the sewer system (Los Angeles area) to make sure heavy metals and petrol based products don't make it out to sea.

I thought the dude was just feeding me BS to ensure we don't cancel our acct. But then our printmaking dept was hit with a $10k fine for improper turp disposal.

Daniel Stone
29-Sep-2011, 13:56
if you have any liquid chemicals, pour them in an old PLASTIC bucket and let them sit out in the sun for a few days. Put a grate over it so animals(especially dogs/cats) don't drink it. Let the water evaporate, and then bag and throw out the "dust". Wearing a mask might be a good idea, as some chemicals aren't nice to be inhaled, even if you don't think you did, just wear a mask out of good practice.


Neal Wydra
29-Sep-2011, 14:48
Dear jennirose,

Check to see if there is a household waste facility in your area. I live in the Chicago area and bring my spent chemistry to a location on the near northwest side.

Neal Wydra

29-Sep-2011, 15:08
As Neal said, start by checking with your city/municipality. Here in Seattle they advise combining developer and stop bath together, which can go down the drain. Fixer however cannot, but can be turned in for free at collection facilities.

I started with a google search for "household hazardous waste seattle" and took it from there. I suspect rules will vary by municipality.

Mark Sampson
29-Sep-2011, 15:12
Any photo lab will have silver recovery equipment and be glad to take your used fixer. When you do that it is recycled and not lost. They may make a few pennies on it, but few amateurs use enough fixer to make silver recovery cost-effective. Don't pour it down the drain or treat it as hazardous waste!

Doremus Scudder
30-Sep-2011, 03:04
Let's try to be a little more specific and help jennirose to properly dispose of her old chemicals without going to unnecessary trouble. Certainly, many of the above suggestions are viable, but most black-and-white chemicals can be safely disposed of into the municipal sewer system. I would recommend against drying everything out and disposing of the dust haphazardly (i.e., in the trash/landfill). The chemicals break down much faster and more efficiently in the water-treatment facility.

And, while taking everything to the hazmat facility is certainly laudable, it is not necessary and often a lot more hassle than needed. Plus, in the case of fixer, I have found that the hazmat guys don't know what they are doing and I doubt the fix goes in for silver recovery; it just gets labeled "photo chemicals" and goes who-knows-where.

First, jennirose, get Kodak's tech publication J-300 "Environmental Guidelines for Amateur Photographers" here
http://www.kodak.com/ek/US/en/Global_Sustainability/Health_Safety_and_Environment/Publications_Library/Waste_Management_Publications.htm and read it. (Right-click the link and save the document. Note that their recommendations for disposing of stop baths apply to concentrated stock solutions, not diluted working solutions.)

Second, if you are on a municipal sewer system, there are only a couple of things you need be concerned about.
1. disposing of heavy metals/toxins into the sewer system.
2. disposing of concentrated acids and alkalies that may damage plumbing

In the first category are USED photographic fixer and selenium toner not used to full capacity (see some of my other posts for replenishing and reusing selenium toner if you are interested).

In the second category comes concentrated acids (including stop bath concentrates and 28% glacial acetic acid) and sodium hydroxide.

As mentioned above, used fixer is best taken to a local photo lab for silver recovery. They are usually very happy to do this, as they make money on the recovered silver. If your area lacks a photo lab (as mine does), collect your fixer in larger quantities and take it to the hazmat facility every now and then (I do this twice a year only).

Note, unused but expired fixer working solution can be discarded down the drain.
Used, unused and expired developers can be discarded down the drain.
Used and exhausted stop baths at working strength can be discarded down the drain.
If you are discarding both stop and developer at the same time, mix them together to neutralize the pH a bit and then discard them.

Concentrated stop baths and acids last forever, so you should not need to discard them. Use them. The same for concentrated and powdered alkalies. If, for any reason, you do need to discard these chemicals, dilute them to working strength or weaker and try to neutralize them before dumping. (Do NOT mix concentrated acids with concentrated alkalies! Dilute everything first to very weak, and then slowly combine them. If there is a violent reaction, you have not diluted enough.)

Some old fixer concentrates do expire (e.g. TF-4 has a one-year shelf life). If you need to discard this, then dilute it to working strength or weaker and discard it down the drain. Powdered fixers last for years and years. Use them.

The same with developers. If you have liquid concentrates, make sure they are bad before discarding. HC-110 and Rodinal last forever, as do powdered developers. If you need to discard a concentrate, dilute it to working strength or weaker before dumping it down the drain.

If you are disposing of lots of chemicals, use plenty of water to flush and dilute. Here's where you need to watch out if you are on a septic system. Septic systems don't like big surges of chemicals. If you mix stop and developer and dispose of it over a longer period of time, you should have no problems. The same for unused fixer (all these chemicals are a lot easier on the septic system than laundry bleach). You need to give the system time to recover, so discard a few liters every day or so to be on the safe side.

If you have used toning solutions or color chemicals, do post back for specific recommendation on them.

Hope this helps,

Doremus Scudder

30-Sep-2011, 06:37
Thank you everyone! This is very helpful. Doremus, unfortunately I also don't have a professional lab nearby, so I think I'll just follow your route and save it up over time.

And as it turns out, what I thought were the chemicals giving off a rotten odor (the reason I was worried they might need to be disposed of in a special way) was actually a dead mouse behind all my bottles. So that was fun to discover last night. Hoping that problem is over and done with though so I can get back to printing!