[BigMackCam]

As I intend to try my hand at B&W film developing at home, I've been researching how to dispose of waste chemicals and chemical solutions.

I realise this has been discussed repeatedly in various forums over the years, and I've read many of those discussions - however, I believe (certainly I hope) we're all trying to be much more environmentally friendly these days, so I trust you'll forgive me in adding to those discussions.

Although I won't be shooting a lot of film (at least, I don't think I will ), I'd still like to minimise the environmental impact of my activities.

Where I live in the North East of England, I've found that a permit is required for individuals to dispose of hazardous chemicals at selected local HWRCs (Home Waste Recycling Centres). The permit is free; applied for, approved and issued online; and, according to what I've read, it happens almost immediately (within minutes). A maximum of 12 permits can be requested per year, per household. Importantly, a maximum of just 2 litres of hazardous liquids can be disposed of per permit issued.

Assuming I use developer, stop bath and fixer that all qualify as hazardous or environmentally unfriendly chemical solutions, I'm going to end up with 3 x 300ml (0.9l) of waste for each 35mm film developed, or 3 x 500ml (1.5l) for each roll of 120. Given the 2 litres per permit and 12 permits per year limits, that means I'd be limited to developing ~26 rolls of 35mm *or* 16 rolls of 120 film each year - unless, of course, I pay a company to dispose of the chemicals for me.

Despite my best intentions, I don't envisage shooting more than one or two films per month at most, so the limits - whilst a little surprising - aren't likely to be a problem for me. However, I'd like to minimise my trips to the HWRC.

Now come my questions:

1) Do I need to treat my washes - including the final wash with wetting agent - as hazardous chemicals, or can these be safely disposed of at home? If they're also considered hazardous, this alone will come to more than 2 litres

2) If I use steel wool in a waste container to remove silver from the fixer (which I believe collects as a sludge), is it safe to dispose of the remaining liquid portion at home, and merely take the sludge to my recycling centre?

3) Since I'll be trying water-only stop baths at some point (given both positive and negative opinions on this, I need to try it for myself), is it safe to dispose of the water-only stop bath at home?

4) Further down the road with my film adventures, I may try Caffenol as a developer. Once used, is this safe to dispose of at home?

When I say "safe", I mean safe for the pipe-work in my home, the drainage system in my residential area, and for the environment in general.

Thanks in advance for any advice and/or opinions

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Last edited by BigMackCam; 10-06-2021 at 12:57 AM.

[BarneyL]

Stop bath and fixer solutions are reusable. You don't have to dispose of these after each development (although I guess some silver and fixer remains will go to the drain after final wash, but I wouldn't worry much).

Calling stop bath a hazardous chemical is a bit of a stretch (citric acid). As you said, you can also just use tap water as stop bath (not recommended after short dev times or positives). The water stop is not reusable, it gets contaminated with developer over time (less of a problem with acidic stop), but there shouldn't be a problem to treat it as one shot solution (the amount of developer particles in the stop bath shouldn't have much of an impact, unless you use something like pyrocatechin).

Some developers are multi use too, but you have to keep track of how many times you reuse and adjust the dev time accordingly. However, of you'd prefer one shot developers like rodinal, the amount of it used per development is miniscule and your permit grants a lot room for it.

Caffenol is generally considered environmentally friendly recipe and I wouldn't consider that hazardous chemical either.

I'm not sure how hazardous wetting agents are, but those are also used in a very dilute amounts, like 1:200 or something like that.

[steephill]

Concentrate your efforts on developer disposal as that can contain the most "unfriendly" chemicals. Stop bath is essentially dilute vinegar, acetic acid, so can be flushed down the sink. Wash water is also OK to flush away. Fixer can also be flushed away safely. One exception would be if you have a septic tank sewage system then don't put any photo solution in there.
Check the health and safety advice from the photo chemical producer. Ilford for example say that all of their solutions can be safely flushed away by domestic scale users.

[MarkJerling]

Mike, I'd not be too concerned about the one, but the other needs a bit more research.
I understand you intend using Agfa Rodinal Compard and Ilford Rapid Fixer. A quick search of the material safety data sheets for those products show that the ingredients of those products are as follows:

Agfa Rodinal Compard:
3% Potassium Hydroxide. This is the base material for most soaps. Also the best drain cleaner money can buy.
30-40% Potassium Sulfite. When mixed with water, it forms potassium hydrosulfide and potassium hydroxide. Potassium hydrosulfide, when mixed with an acid will form highly toxic and flammable hydrogen sulfide. So, potentially this may not be that good down the drain. But, you're not mixing with an acid, you're mixing with an alkaline solution, so, not a problem.
1-5% Potassium Bromide, sedative and anti-epileptic drug, fine to flush.
1-5% p-Aminophenol, hair colouring dye from coal tar, fine to flush.

So, basically, if you flush this down the loo you're flushing really good quality drain cleaner.

Ilford Rapid Fixer:
36-50% Ammonium Thiosulphate. Fertilizer. Not bad for the sewerage system but not that great for the environment.
1-5% Sodium Bisulphate. Basically an antiseptic solution. Fine for the drain, but not great for the sewerage works.
>2% Acetic Acid. Mild vinegar.

So, if I was going to wonder about what to do with these two, I'd flush the Rodinal but not the Fixer, but in the volumes you're dealing with, it's probably fine.

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Last edited by MarkJerling; 10-06-2021 at 02:33 AM.

[FozzFoster]

1) Do I need to treat my washes - including the final wash with wetting agent - as hazardous chemicals, or can these be safely disposed of at home? If they're also considered hazardous, this alone will come to more than 2 litres

1. I'm pretty sure wetting agent is similar to 'Jet Dry' in a dishwasher. I've been operating under the impressing that it's ok to drain the wetting agent...
2. I've never heard about the steel wool trick...
3. The Stop will have slight residual developer in it too. One purpose of using a Stop is to limit contamination of your Fix with the developer (which would reduce effectiveness faster). So if you even just use a water stop, it's going to have developer in it.
4. No - even if you use 100% natural developer, you are still dissolving the chemicals off the film. So all the chemicals wash off the film and will be mixed in your Caffenol - still not good for the sink, imo.

[Bob 256]

Photo chemicals which got the bad rap were from color processing generally, and included color developer (which used to include a really toxic reversal agent), the bleach which had cyanide components (not the really bad ones however), and stabilizer which had formalin attributed to cancer causation. Most of that has changed in newer color chemicals.

Black and white chemicals, on the other hand, are relatively benign in comparison. Most are attacked by bacteria and converted to harmless substances in short order. One chemical used in B & W which causes serious problems is silver itself which is toxic to bacteria. It's recommended that you not dump used fixer into a septic system (tank) for that reason - it can kill the bacterial activity in the tank which isn't good. In the general sewage system however, it's diluted very well and doesn't cause issues unless large quantities are being disposed (and then silver recovery is usually in place to remove a good portion of the silver before disposal takes place, as you mentioned you're doing). Only one B & W chemical comes to mind in terms of being hazardous and that's pyro developer which has carcinogenic properties (there are also specialized ones like bleaches, toners, reducers, etc., however, which need examination).

In summary, home processing of B & W materials doesn't pose much environmental harm so you don't really need to worry about disposal that much, however it's very good that you're concerned and willing to take measures to help the environment.

[stevebrot]

To reinforce a few of the above comments, the chemicals used in B&W processing are of low environmental and wastewater concern, with the possible exception of silver in the fixer. Details:

-- Developers: These are highly reactive (strong reducing agents) in concentrated state, but much less so at working dilutions when sent down the drain with a liberal chaser of tap water. Once in the waste stream, they are readily biodegradable.

-- Stop bath: This is a weak solution of acetic acid (think vinegar) and quite safe and biodegradable down the drain.

-- Fixer: The fixer itself poses little hazard or waste stream concern, except for the silver it leaches from the film during use. If one has the means to recover the silver, it is good to do so.


Steve

[jbinpg]

One of the main reasons I decided on caffenol processing was the minimal amount of chemicals flushed down the drain. Even the fixer can be taken care of by the "steel wool in a bucket" procedure.

[fs999]

I put my Caffenol in the drain and my fixer in a 25 litre can with the C41 and E6 liquids. When it is full i bring it to the local recycling centre with the empty cans of the concentrates.

[Alex645]

1) Do I need to treat my washes - including the final wash with wetting agent - as hazardous chemicals, or can these be safely disposed of at home? If they're also considered hazardous, this alone will come to more than 2 litres

2) If I use steel wool in a waste container to remove silver from the fixer (which I believe collects as a sludge), is it safe to dispose of the remaining liquid portion at home, and merely take the sludge to my recycling centre?

3) Since I'll be trying water-only stop baths at some point (given both positive and negative opinions on this, I need to try it for myself), is it safe to dispose of the water-only stop bath at home?

4) Further down the road with my film adventures, I may try Caffenol as a developer. Once used, is this safe to dispose of at home?

1) The amount of residue in washes is negligible and can go down the drain. Wetting agent is only a surfactant and no more harmful than a weak dish washing detergent.

2) Check the legal limit of silver disposal in your state or locality. The EPA sets a limit of 5 ppm (mg/L) for silver, but in my state the limit is .05 ppm (mg/L). For B&W chems, silver is the greatest concern; it is an antibiotic and will kill 'good bacteria' at sewage treatment plants used to kill 'bad bacteria' like e.coli. Some photographers bend the rules by just flushing a ton of water with their used fixer so that the ppm is legal, but to me, that same amount of silver waste is going downstream and really should be removed at the source.

Depending on the effectiveness of your silver recovery process, the remaining liquid should be within limits of going down the drain.

3) Yes, water-only stop bath is fine down the drain.

4) For all chems, I use a dilution tank with limestone chips between the drain and the sewage pipe. The dilution tank helps to neutralize the alkali developer and fixer with the acidic stop bath and the limestone chips (calcium carbonate) help to neutralize chemical in the effluent.

My practices with these discharges is because I run a lab with up to 20 students and as an educator, I want future photographers to do the right thing as well. Solo, your impact of what you put in your waste water is minimal which is why the EPA in the US visits me every year, but wouldn't bother individuals purchasing photo chems.

IF you have a septic tank, or are in a community that uses a septic system, and if your water comes from a well on your property, then I would dot every i and cross every t.

Online you can acquire PDFs of each chems MSDS (material data safety sheet) that outlines all the details for you to know what you're dealing with for Caffenol or Cawanol.

[BigMackCam]

Fantastic feedback and information - thank you, everyone!

I'm not on a septic tank system; my waste goes directly into the main sewerage and drainage network.

So... in summary:

- Agfa Compard Rodinal R09 is OK to flush in its diluted form (I will be using 1+50, based on advice), being very much like a caustic drain cleaner (but check each developer I may use in future)
- Acid stop bath - reusable, waste is OK to flush
- Water stop bath - OK to flush
- Ilford Rapid Fixer - re-useable, waste needs silver removal, but even then contains chemicals unfriendly to the environment and sewerage works
- Wash and final wash with wetting agent - OK to flush

I understand that I could probably flush the waste fixer after removing as much silver as possible (steel wool in the container would be my approach), given the low frequency and volume... but I'd rather be over-cautious, do the right thing and drop it off at my recycling centre. With the volume of films I'll be shooting, I should only need to go there every couple of months at most

Thanks again, folks - very much appreciated!

[y0chang]

Rodinal even diluted really shouldn't be dumped down the sink.
The MSDS states that it is a Water Hazard 3 which means even small quantities can be deadly to aquatic life.

https://www.freestylephoto.biz/pdf/msds/adox/ADOX_ADONAL_(GB).pdf

Kodak X-TOL is much less toxic than metol developers like D76 or Rodinal.

[Wheatfield]

To reinforce a few of the above comments, the chemicals used in B&W processing are of low environmental and wastewater concern, with the possible exception of silver in the fixer. Details:

-- Developers: These are highly reactive (strong reducing agents) in concentrated state, but much less so at working dilutions when sent down the drain with a liberal chaser of tap water. Once in the waste stream, they are readily biodegradable.

-- Stop bath: This is a weak solution of acetic acid (think vinegar) and quite safe and biodegradable down the drain.

-- Fixer: The fixer itself poses little hazard or waste stream concern, except for the silver it leaches from the film during use. If one has the means to recover the silver, it is good to do so.


Steve

I read a (possibly self serving) release from Kodak a few decades ago that indicated the silver in waste fixer was so tightly bound to the thiosulphate that it was environmentally inert.

California, back in the 1990s IIRC, passed laws limiting the amount of silver that was allowed to go down the drain, aiming the law directly at the lab industry.
What they didn't take into account was that in many parts of the state the level of naturally occurring silver in the water was greater than what was allowed by law.

[Alex645]

I read a (possibly self serving) release from Kodak a few decades ago that indicated the silver in waste fixer was so tightly bound to the thiosulphate that it was environmentally inert.

California, back in the 1990s IIRC, passed laws limiting the amount of silver that was allowed to go down the drain, aiming the law directly at the lab industry.
What they didn't take into account was that in many parts of the state the level of naturally occurring silver in the water was greater than what was allowed by law.

Waste fixer generally contains 3000-8000 parts per million of silver. Although local waste water laws vary in different counties and states, in the U.S. the federal limit for silver waste is 5 ppm. Silver is an antibiotic that kills bacteria used at sewage treatment plants to neutralize harmful bacteria like e. Coli.

If there is naturally occurring silver in the tap water source, it will come no where close to 3000-8000 ppm.

[Wheatfield]

Waste fixer generally contains 3000-8000 parts per million of silver. Although local waste water laws vary in different counties and states, in the U.S. the federal limit for silver waste is 5 ppm. Silver is an antibiotic that kills bacteria used at sewage treatment plants to neutralize harmful bacteria like e. Coli.

If there is naturally occurring silver in the tap water source, it will come no where close to 3000-8000 ppm.

I think you read my post to respond, not to understand. What you wrote has little to do with what you are responding to.