Photographic chemical disposal

[jnantz]

A simple way to remove silver from used fixer is to place some aluminium foil in it. The silver precipitates and can then be filtered out. In the process the aluminium is used up. Once you get enough silver it can be sold.

then what do you do with the aluminium-saturated water ?
are there problems with having aluminium in the septic / sewer system / ground water ?

[koraks]

They put on isolation suits and labeled my used fixer for incineration (wow, that's really good for the environment...).

Incineration actually could make perfect sense, depending on the scrubbers/cleaning methods of exhaust gas used. In any case, it may very well be a lot more environmentally friendly than flushing it down the drain.

[tgtaylor]

I would do a google search for Household Hazardous Waste disposal sites in your county. Here in Alameda County we have 4: http://www.stopwaste.org/recycling/r...t-hhw-facility

They accept photo chemicals as long as they are in leak-proof containers with the contents identified. You just fill out the form which can be downloaded on the website, hand it to the worker and pop the trunk and they take it out and place on a sorting table. That's all there is to it here.

Thomas

[David Lobato]

I'm very familiar with using and disposing of normal B&W darkroom chemicals. But, what about the chemicals used in alternate processes? There are Dichromates, and Potassium Ferrocyanide, among others, that one needs to be careful with when handling. What are the proper disposal protocols for these? This is the main reason I have not tried alternate processes.

[jp]

For alt process, I've avoided Dichromates because I use a septic system and don't want that in my soil. Some people say there are ways to neutralize that, but I haven't heard anything authoritative enough to change my mind.

Fixer I save and use jnanian's silver maget to remove silver before dumping it.

I don't use selenium toner, but that would be a good thing to recycle.

Developer goes down the drain.

I use water stop bath.

Potassium Ferrocyanide is not toxic.

[tgtaylor]

They accept alt chemistry here in California. I haven't inquired about uranium nitrate but I suspect that then will also accept that also but I intend on using all of it.

Thomas

[Maris Rusis]

I've had the luck to enjoy a career in scientific research and analytical chemistry before taking up photography full time. One of my challenges was teaching chemists at the local water supply and sewerage department about photographic chemicals in the effluent they had to treat. The "no fixer down the drain" anxiety comes up about a hundred times a year and has been doing so for at least half a century.

The rules about disposal of photochemicals are driven by fear and ignorance about "chemicals". Even Kodak publication J-300 which is the de facto last word on "fixer down the drain" is more about avoiding legal disputes and less about chemistry.

The following does not apply to industrial scale photo materials manufacturing or a major processing lab, only households connected to a sewer line or a proper septic system:

Developers are mild reducing agents that oxidise rapidly to inert components. The BOD (Biological Oxygen Demand) challenge offered by a home darkroom is much (very much!) smaller than the BOD from a single dishwasher, in-sink garbage disposal unit, or a toilet.

Stop bath is a very mild acid that has no measurable effects on highly buffered systems like septic tanks or sewerage treatment plants.

In moderate quantities (ounces, not tons) silver tetrathionate and similar compounds which characterise used fixer can't and don't harm sewerage treatment systems or septic systems. The silver very quickly gets converted to silver sulphide in the presence of the free sulphide ion (smells like rotten eggs!). Silver sulphide is geologically (millions of years) stable and biologically inert and has one of the lowest solubility products known in chemistry. The stability and inertness of silver sulphide is the key to the remarkable archival properties of sepia toned photographs.

Do your own calculations. Just estimate your yearly use of silver from your photographic materials consumption, allow 1 milligram per square inch, and divide this by your yearly water consumption from the water meter. I bet it's in the parts per billion range where no conceivable biological effect can be credibly imagined. I did this for my own darkroom and found a value of 0.5ppb which is about the same as the local river water.

If you are discharging into a sewer system your used fixer contribution will be diluted by thousands of household that don't do photographic processing; that's just about everybody. Down at the treatment plant your speck of silver won't be detectable by any known analytical technique. People washing silverware in their dishwashers or polishing silver or EPNS plate will send down incomparably more silver than you will ever do. The cohort of people who are into the health fad of adding colloidal silver to drinking water excrete more silver (legally!) than a rare home darkroom.

Perhaps it is worth being anxious about putting home darkroom effluent down the drain because the harm you could encounter would take the form of prosecution and penalty. A scofflaw could tip all their small scale photo-chemistry down the drain, never get caught, and do no harm to anything. The decision is maybe more about morality than chemistry

[rob4x5]

Thanks for posting this. It has been my thinking all along. I have been pouring my chems down the drain for years with no problems to my septic system.

[jnantz]

people often quote j-300 as if it were written yesterday by kodak
it was written almost 20 years ago .. and kodak changed their tune in 2005
http://web.archive.org/web/201606150...bs/ak3/ak3.pdf
they say not to put anything down the drain ( septic ) and follow local regulations (sewer) ...

[ben_hutcherson]

I am an analytical chemist, and my university's hazardous waste department and I are always working together to negotiate sink disposal of chemical waste with the sewer department. We finally got them to relent on the huge volumes of acid/base titration waste from freshman teaching labs. When HCl and NaOH are titrated to a neutralish pH(neutralish depending on how good the student is, but generally not over 8 or under 6) we're disposing of salt water-it was asinine to have to dispose of 100+ gallons of saltwater through our normal disposal channels. We do another experiment where the students use Congo Red in low concentrations-this is the same coloring agent used in Big Red Cream Soda.

I would not and do not bat an eye over putting developer down the drain(at home). The compounds used will not hurt the bacteria in the disposal plant, and they may even like them . I use D76 one shot, so am usually dumping 16 oz. of either straight D76 or 1:1 down the drain at a time. I would worry about fixer if I had a septic tank as that's a small enough volume that the silver can upset the ecosystem in it, but a quart of fixer down the drain(that's the quantity I mix and then use to exhaustion) won't hurt the treatment plant. With that said, I do recover my silver and am waiting until I have enough to make selling it viable. By the time I dump my fixer, it tends to have a fair bit in it.