How much silver is actually in modern films and papers?

We're a local photo lab having a feud with the local environmental authorities who accuse us of dumping silver into the waste water stream. The only fix that goes down the drain is from washing. We bottle up used fix, developer, stop, and toners and send them to the hazardous waste disposal.
They want us to install an incredibly expensive disposal system or they're threating us with shutting us down.
Any chemists that can point us in the right direction to make our case? Koraks?

thanks in advance,
old-squint

Where are you located?
The more important question should be: "how much silver is in your used wash water?
That is something that can be tested and monitored.

The silver in the film or paper -- which really isn't much -- goes to two places.

#1 -- it's was exposed and developed and stays in the film or paper.

#2 -- it wasn't exposed and is removed by the fixer.

There's basically nothing left to go down the drain in the wash water

xkaes said:

There's basically nothing left to go down the drain in the wash water

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Not quite - but the levels are very, very low, and they can be tested for.

Good grief... this reminds me of an old battle axe photo teacher in my district (thankfully retired!), who switched entirely over to digital, then went to the district to try to get us other heathens to also switch over to digital, for the very same reason. Us heathens won.

Have you measured silver in your effluent (or had it measured) and compared that with the environmental standards? That would seem the first move. Your problem may simply disappear if you can present results that show you don't discharge more than allowed.

This has nothing to do with how much silver is in films and papers, but rather how much is in your wash water.

Talking to other labs in the industry as well as regulatory authorities may give you an insight as to what they do. I don't know how much clout opinions from a forum is going to have in your case.

Doremus

You don't specify where "local" is. Regulations vary, and the burden of proof might be upon you, based on actual sample tests, not anything hypothetical. Silver can be quite bad for certain ecosystems or wastewater systems. Since your spent fixer is sent to hazmat, one would imagine that anything remaining in the wash water would be minor; but it would still have to comply with THEIR specified standards. You'd need to know exactly what that standard is, whether you're in compliance or not (based on independent testing), and whether exemptions for small businesses are possible. Try to work with them rather than being adversarial. "Feuds" in such cases always end badly. There must be some kind of polite appeal process if your side of the argument is within reason; but you'd first need hard proof on your side that the impact of your own effluent is negligible.

Even the categorization of rules can vary place to place. In my particular region, for example, home darkrooms and even teaching darkrooms are largely exempt from scrutiny. But any commercial lab, large or small, would be held to a different standard, and be expected to install silver recovery equipment.

It is very unlikely that you releasing any metallic silver during washing, perhaps there is some small trace of a silver halide complex at most during the first moments. During washing you are removing thiosulfate from the film or paper. Silver is in the film or paper in metallic form and dissolved in your fixer as part of a compound.

ole-squint said:

Any chemists that can point us in the right direction to make our case? Koraks?

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Well, I'm not a chemist, and I don't have the definitive answer on how much silver there is in today's materials. AFAIK 5-10g/m2 is still a reasonable ballpark figure. Maybe @ADOX Fotoimpex could confirm whether this is the case.

I can see how the absolute silver load might be part of an argumentation if your argument is going to rely on a reasoning like this: "assuming we were to dump all of the silver we process down the drain, and relate that to our total effluent (from flushing toilets as well etc.), we'd still remain below the permissible limits set by the regulator." You could then follow that up by "of course we don't do that and only a fraction ends up in the sewer, so logically we remain far below the permissible limits." IDK if the numbers work out that way; you can do the math based on your film & paper consumption/usage patterns, your water use (which evidently goes down the drain for the most part) and what data you can find on permissible discharge of silver.

A few things don't work to your advantage, however. Firstly, as I recall, you're in Europe (Norway if memory serves?) and I expect that the permissible limits to silver discharge are really, really. low. Secondly, I suspect that you'll qualify as a business, not a consumer/household, which may (likely) make you end up in a more strict legal regime. Thirdly, the question is how much credence local policy bodies will grant to essentially a layperson and their private opinion/analysis.

I think in your place, my approach would be a two-staged approach. First, try to figure out why you're being targeted. Environmental authorities have little interest in tiny little fish like the local amateur darkroom club. They're only likely to become nasty if someone has suggested/forced them to do so. Perhaps someone filed a complaint or tipped off the authorities and they feel pressured to act on this. You may be able to find out what's really going on and then see if you can deal with the cause. In cases like these, it's not unheard of that the authorities end up being reasonable if you can point out how/why the original complaint/tip was nonsensical and perhaps based on ulterior motives. They might simply drop the case once they recognize that it's just "angry Pete complaining about the photo guys after having made life hard on the local pub owner, the petting zoo volunteers, a supermarket because of the car park issue, etc." Figuring out what's going on starts by having a dialog with the authorities that goes beyond the immediate (supposed) issue of discharge and explores the context in which you're being targeted. A meeting and/or some phone calls tend to work well (as opposed to emails, letters etc.)

If that route fails and the authorities keep on the pressure, I'd to try and network my way towards a legal professional who is aware of how to deal with legislators running amok and becoming unreasonable (which IMO is what we're seeing here). They might be able to work out with/for you whether the environmental agency has the legal pretext to target you to begin with, and if so, what that basis is and how it might be argued against. It's possible that in this process, you'll have to rely on an expert assessment. In that case, it's of course going to matter what the expert says, but first and foremost who they are (i.e. do they have an academic title, an active research position at a recognized institutes, and some kind of credentials that make them a credible party). So even if it comes to that, what you, me or anyone else on Photrio says really isn't going to matter all that much, except maybe give some direction in which to look for an argumentation.

I'm sorry to hear that you're in this position. I'm afraid that the present legislative/administrative climate doesn't favor the kind of things we do, regardless if we're being sensible about what we do and how we do it. The fact that we work with "chemicals, oooooohhhhhh, baaaaad stuff!" poises you/us for an uphill battle to begin with. Public sentiments and overall ignorance sadly don't help much, either.

ole-squint said:

We're a local photo lab having a feud with the local environmental authorities who accuse us of dumping silver into the waste water stream. The only fix that goes down the drain is from washing. We bottle up used fix, developer, stop, and toners and send them to the hazardous waste disposal.
They want us to install an incredibly expensive disposal system or they're threating us with shutting us down.
Any chemists that can point us in the right direction to make our case? Koraks?

thanks in advance,
old-squint

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"Local" to where? How expensive is the system?

I've not heard of people trying to recover silver from wash water. Fixer and blix absolutely.

Back in the 1970s, the North Vancouver Kodak Canada Kodachrome/Ektachrome lab had to install an additional layer of effluent treatment because trace amounts were showing up in their 3rd wash water discharge.
That is after the first two complete washes, which were expected to require treatment, and were treated.

In some municipalities there are various hookup and inspection fees too - really a form of added local taxation, but unavoidable under certain business classifications. Be grateful you're not back in the Cibachrome days when sulfuric acid was a predominant lab effluent - easily neutralized by individual users using simple baking soda, but truly expensive to deal with on a big commercial processing scale.

On the issue of how low of a concentration of silver can be measured, as a rule of thumb inductively couple plasma mass spectrometry can measure some metals down to the parts per billion level in solutions, and sometimes even much lower.

Employ an industrial chemist to analyze the water and write a report. If toxins dont exceed to regulated amounts you should not need to do anything, if they you'll need to work a solution.
Generally there are rules on what is acceptable and it has a low bar, other wise drinking water in some places wouldn't be fit for human consumption.
The EPA needs to prove you exceed the acceptable amounts, other wise you can take them to court.

Oh and as someone who deals regularly with regulative bodies professionally, it's best to know the rules and try and work with the regulators. Sometimes you can work out a better solution.....brown nosing helps.

Call the state. If you're looking for an element like silver it's a very straightforward ICP, AA, emission spectroscopy. State Hygienic labs test for heavy metals, it's a cheap (once you have a $200,000 ICP spec) test.

mshchem said:

Call the state

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I don't think OP is in the US. Regulatory environment is likely different. However...

awty said:

brown nosing helps.

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I'd not call it 'brown nosing' per se, but a collaborative attitude tends to go a lot further than trying to fight. I'll wager to state that a darkroom enthusiast's club does not quite have the financial clout that even a low-level regulatory body in a European country has.

I am checking spanish regulation and maximum silver content in an efluent is very low even for a trace (0,1 mg/liter or 0,1 ppm). Perhaps OP can try a washless process similar to minilab machines: squeeze film from fixer and pass it though three baths of final rinse (similar to two-bath fixing).

Probably it is not only important the silver-content in the wash-water (which is probably extremely low), but how much of that wash-water silver is really reaching the waste water plant. I remember the explanation by a chemist many years ago in a photo forum who said that because of the specific weight of the silver it is sedimenting / settling in the the waste water canals or tubes. And not reaching the waste water plants (at least not in volumes which would create any problems with the microbes who are used in these plants to clean the water).
But I am no chemist, I cannot assess it.

JParker said:

the specific weight of the silver it is sedimenting / settling in the the waste water canals or tubes

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This only holds true (to an extent) for solid silver particles. The silver that goes down the drain in a photographic setting is in the form of soluble silver-salts. There will be some precipitation due to silver ions swapping places with other metals, resulting in the silver dropping out of solution in solid form. But the extent to which this happens is virtually impossible to determine, and even as it happens, most of that silver will be so finely divided as to be washed away down the tubes and culverts with the res of the muck. At best, it's delayed a little.

Since 1981, every photo lab that I've worked for, or did business with, has had a silver recovery unit. If you don't have one, at the very least you're throwing money away (sending spent fixer to hazardous waste disposal is just that). They are not impossibly expensive- it's a business expense after all.
As far as measuring effluent, what practices have your competitors (who work under the same rules) do? This is a solvable problem.

MarkS said:

Since 1981, every photo lab that I've worked for, or did business with, has had a silver recovery unit. If you don't have one, at the very least you're throwing money away (sending spent fixer to hazardous waste disposal is just that). They are not impossibly expensive- it's a business expense after all.
As far as measuring effluent, what practices have your competitors (who work under the same rules) do? This is a solvable problem.

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It sounds like the OP is using silver recovery on used fixer and/or sending used fixer to a facility to deal with it.
This is a question about silver in the wash water.

This is kinda funny. I was involved in implementing water filtration in US domestic refrigerators. One scheme for removing lead from water was a ion exchange resin that captured lead and released silver into the purified water. This was a very common practice.

ole-squint said:

We're a local photo lab having a feud with the local environmental authorities who accuse us of dumping silver into the waste water stream. The only fix that goes down the drain is from washing. We bottle up used fix, developer, stop, and toners and send them to the hazardous waste disposal.
They want us to install an incredibly expensive disposal system or they're threating us with shutting us down.
Any chemists that can point us in the right direction to make our case? Koraks?

thanks in advance,
old-squint

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Sorry to hear about your predicament but I have a suspicion that they are right (you haven't given enough information to know for sure, not even what country you're in).

My experience has been in the USA and, to a very limited extent, Canada. In the US most photofinishing operations put their "effluent" into a sewer leading to a POTW (publicly owned treatment works), aka the sewage treatment plant. Such photofinishers are NOT regulated by the EPA, etc., but rather by the local municipality. (The EPA regulates the POTW, and because of this the local municipality makes its own laws as to what users are allowed to put into its sewers.) The way the individual users (photofinishers, etc.) are regulated is via a "sewer permit" which allows them to be connected to the local sewer system. This permit specifies allowable limits of certain chemicals, etc., as well as certain data that the photofinisher is required to report, etc. And if the photofinishers fails to "comply" ... well presumably they can be "disconnected" from the sewer.

I really don't know how other countries deal with these issues but suspect that the fundamental ideas are similar.

The typical photofinisher sewering permit in the US would specify allowable silver concentration in the effluent, as well as limits for BOD and COD (the "...OD" part stands for oxygen demand), loosely how much oxygen is used as the chemicals are degraded. The allowable silver concentration can vary substantially. At the large lab outfit where I worked our permit limited silver concentration to 0.2 mg/L, which would be virtually impossible for the normal person. (This is roughly 0.2 parts per million, which is numerically equivalent to controlling the population of New York City, population ~ 10 million (?), to within 2 people.) "Normal" wash water from a film processor would be way higher than this limit.

I have a suspicion that the local authorities took a sample of your effluent, and the chemical analysis for silver was considerably higher than your regulations allow. So I would say that you should start by finding out what limits are allowed, and what was found in your effluent. Perhaps you have a sewering permit already?

FWIW our sewering permit required us to take a full workday flow-proportioned samples each month, and report the results by a "certified" analytical lab. You might try to make the case that perhaps. something was "wrong" with your local authority's sample, giving an "abnormally high" result, and request a new sample. And that YOU want to split the sample so that you can have one analyzed by your own lab. It kind of depends on how far off you were.

FWIW I wouldn't wanna put too much private information out on a public forum like this. Best of luck with things.

Here in the US, even in the most highly regulated States, Fed EPA inspectors are far and few between. Most of them are tied up on huge Superfund site operations or monitoring egregious Tech industry effluent, along with illegal pesticide trafficking. They don't have time to pester the little guy. State EPA has a somewhat different footprint, and then there are all kinds of regional air and water control bureaus, along with municipal boards. If there are discrepancies involved between agencies (and there are a lot of them), the most stringent rules apply. Downright illegal operations like meth labs are more an FBI and local law enforcement issues, but they're often tipped off by wastewater sampling (or flammable explosions!).