[Alex645]

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

I only understand the info of what you wrote. You stated that you read a Kodak release that claimed the silver waste was so tightly bound to the thiosulphate that it was environmentally inert. Would you like to explain further what does that mean in terms of ppm silver and how that impacts environmental waste limits and laws?

What were the actual trace amounts of silver in California tap water that rendered their waste water silver limits useless? So if the limit is 5 ppm, and the naturally occurring tap water has 10 ppm, it's okay to pour 5000 ppm of silver as discharge? I'm trying to understand your point.

[Wheatfield]

I only understand the info of what you wrote. You stated that you read a Kodak release that claimed the silver waste was so tightly bound to the thiosulphate that it was environmentally inert. Would you like to explain further what does that mean in terms of ppm silver and how that impacts environmental waste limits and laws?

What were the actual trace amounts of silver in California tap water that rendered their waste water silver limits useless? So if the limit is 5 ppm, and the naturally occurring tap water has 10 ppm, it's okay to pour 5000 ppm of silver as discharge? I'm trying to understand your point.

What it means is that Kodak, in a potentially self serving press release, indicated that there was no environmental danger associated with silver thiosulphate.
There were some photo industry releases at the time indicating that in many parts of California, the level of naturally occurring silver was above the limit the state was proposing for waste water.

I wasn't trying to score any internet points. I know where that leads.
I do feel like I'm repeating myself, but you did ask.

[CanonierEx]

I think getting rid of chemical waste is a lot easier than you think. You could dump them out somewhere, but that's not your option since you're looking for a more environmentally friendly way, so you could try the option I use. I use Rubbish clearance Portsmouth by zero waste group who do recycling and recycling of any garbage. So I think the best option for you, would be to find a similar company in your city and your problem will be solved. It's good for the environment.

[BigMackCam]

That sounds kind of dangerous. If I were you, I would think about ecology.

May I ask which post in the thread this is a response to?

[Wheatfield]

May I ask which post in the thread this is a response to?

Mike, I think the real point is that in the very small quantities of chemistry you will be using, just dumping the exhausted stuff down the drain will be OK.
Black & white chemistry is, as has been pointed out, pretty benign stuff. Mostly it has a very low toxicity, and would have to be dumped in large quantities to have a deleterious effect on the environment.
There is much hysteria these days regarding dumping of chemicals of any kind that can be safely ignored.
The pods you use in your dishwasher (if you have one) are likely far more toxic than your B&W photo chemistry, and you use them far more often.

[BigMackCam]

Mike, I think the real point is that in the very small quantities of chemistry you will be using, just dumping the exhausted stuff down the drain will be OK.
Black & white chemistry is, as has been pointed out, pretty benign stuff. Mostly it has a very low toxicity, and would have to be dumped in large quantities to have a deleterious effect on the environment.
There is much hysteria these days regarding dumping of chemicals of any kind that can be safely ignored.
The pods you use in your dishwasher (if you have one) are likely far more toxic than your B&W photo chemistry, and you use them far more often.

Thanks, Bill Given the developer, stop and rinse agent solutions I'm using - and the very small quantities involved - I'm happy disposing of those down the drain. I could probably do the same with the small quantities of exhausted fixer, but I'm choosing to store that and drop it off at my recycling centre as necessary...

[Alex645]

There is much hysteria these days regarding dumping of chemicals of any kind that can be safely ignored.

I could probably do the same with the small quantities of exhausted fixer, but I'm choosing to store that and drop it off at my recycling centre as necessary...

Most of the chems in developer and stop bath are benign but exhausted fixer is going to have high PPM of silver (typically around 400-600 ppm), far above and beyond both federal and state laws. Silver is one of the eight heavy metals highly regulated by the EPA and anything above 5 ppm is illegal and bad for the environment. In Hawaii, the limit is .3 ppm of silver.

It's good that you do dispose of it properly and legally and I applaud everyone who does the right thing. Even if no one would know, you would.

[Wheatfield]

Most of the chems in developer and stop bath are benign but exhausted fixer is going to have high PPM of silver (typically around 400-600 ppm), far above and beyond both federal and state laws. Silver is one of the eight heavy metals highly regulated by the EPA and anything above 5 ppm is illegal and bad for the environment. In Hawaii, the limit is .3 ppm of silver.

It's good that you do dispose of it properly and legally and I applaud everyone who does the right thing. Even if no one would know, you would.

That gets diluted down by the total waste water disposed of by the household, therefore bringing the total silver load down to well within environmental levels.
Also, the compound being disposed of is not silver, it is silver thiosulphate. This makes a difference.
Also, the OP is in Britain, so quoting USA numbers is useless in the context of the thread.

[BigMackCam]

exhausted fixer is going to have high PPM of silver (typically around 400-600 ppm), far above and beyond both federal and state laws

That gets diluted down by the total waste water disposed of by the household, therefore bringing the total silver load down to well within environmental levels.
Also, the OP is in Britain, so quoting USA numbers is useless in the context of the thread.

I'm not sure of the legal limits here in the UK, but I'm erring on the side of caution and following my environmentally-sensitive nature on this, hence dropping my exhausted fixer off at the recycling centre. Given the quantities, I'm probably doing more damage with the pollution I'm pumping into the atmosphere from my diesel 4x4 when I drive there But anyway, I'm trying to do the right thing

[Benz3ne]

BigMack - you could probably work out how much you're diluting it down to. Find approximate figures for the quantities of silver ions in the waste fixer, take an approximate flow rate from your taps (get a litre jug and time 10 seconds, see how much that jug is filled, multiply by 60 and you've got a L/hr reading.
Then how long you approximately have your taps on.
Then you've that x ppm in y mL of fixer, plus that additional water.

You can check this against DWR Cymru's limits, which should be approximately equal to those in England. I know it's been said before but it's worth reiterating I feel.
Typically, you'll be lower than limits, but that's not to say you'll always be lower than limits.

[Wheatfield]

BigMack - you could probably work out how much you're diluting it down to. Find approximate figures for the quantities of silver ions in the waste fixer, take an approximate flow rate from your taps (get a litre jug and time 10 seconds, see how much that jug is filled, multiply by 60 and you've got a L/hr reading.
Then how long you approximately have your taps on.
Then you've that x ppm in y mL of fixer, plus that additional water.

You can check this against DWR Cymru's limits, which should be approximately equal to those in England. I know it's been said before but it's worth reiterating I feel.
Typically, you'll be lower than limits, but that's not to say you'll always be lower than limits.

When I was running my darkroom I just went with my daily average water consumption to figure how much I was diluting stuff, but this wasn't taking into account dilution from my neighbors who didn't have darkroom but still added to total dilution.
The result was effectively zero silver sulfite or thiosulfite being put into the wastewater.
One thing people aren't taking into account, and they should, is that silver sulfite or thyosulfite is not free silver, it is a silver bound compound that is, at least according to Kodak, environmentally inert. One still doesn't want to be dumping gallons per day, but a pint every month or so isn't going to affect anything.
When I made my home darkroom into a business and my chemical usage went up I warehoused my spent fixer until I had 5 gallons of it built up and took it to my local lab for disposal through their silver recovery.

[Alex645]

That gets diluted down by the total waste water disposed of by the household, therefore bringing the total silver load down to well within environmental levels.
Also, the compound being disposed of is not silver, it is silver thiosulphate. This makes a difference.

Yes, for a legal go around, you could dilute 500 ppm down to 5 ppm with a 100:1 dilution, but the reality is that there is still that same quantity of silver in the form of silver thiosulphate going into the environment. Yes, the toxicity is low, but the main issue I've been told by waste water management is that silver acts as an antibiotic which kills both good and bad bacterium.

To quote verbatim another forum on the subject:
Dealing with used fixer: the easiest way is to take a disposable plastic container, stuff it with a wad of steel wool, pour in your exhausted fixer, close the container, and wait a day or two. An oxidation-reduction reaction takes place between the iron and silver, resulting in partial dissolution of the steel wool and precipitation of the silver (mostly as a fine black powder, occasionally as a shiny mirror that forms on the walls of the container).

This process gets rid of the silver ion (the toxic form) and reduces it to metallic silver, which is not toxic. After the process is done, you can dump the liquid down the drain and then throw out the container and steel wool/silver. (There's probably not enough silver to be worth saving.)

[Benz3ne]

When I was running my darkroom I just went with my daily average water consumption to figure how much I was diluting stuff, but this wasn't taking into account dilution from my neighbors who didn't have darkroom but still added to total dilution.
The result was effectively zero silver sulfite or thiosulfite being put into the wastewater.
One thing people aren't taking into account, and they should, is that silver sulfite or thyosulfite is not free silver, it is a silver bound compound that is, at least according to Kodak, environmentally inert. One still doesn't want to be dumping gallons per day, but a pint every month or so isn't going to affect anything.
When I made my home darkroom into a business and my chemical usage went up I warehoused my spent fixer until I had 5 gallons of it built up and took it to my local lab for disposal through their silver recovery.

That’s all good to know but it would be worth clarifying which silver complex(es) you mean.
So far, you have mentioned silver thiosulfate, silver sulfite, silver thiosulfite and silver thyosulfite (?), and used them relatively interchangeably. .
Their safety data sheets can be referenced for their environmental impact, and their toxicity to specific animals/plants/sometimes bacteria.

I really don’t think it’s a bad idea for BigMack to be conscientious about their actions.


Edit: I wrote sodium where I should have silver. Amended.

[Wheatfield]

That’s all good to know but it would be worth clarifying which silver complex(es) you mean.
So far, you have mentioned Sodium thiosulfate, sodium sulfite, sodium thiosulfite and sodium thyosulfite (?), and used them relatively interchangeably. .
Their safety data sheets can be referenced for their environmental impact, and their toxicity to specific animals/plants/sometimes bacteria.

I really don’t think it’s a bad idea for BigMack to be conscientious about their actions.

Actually, I've not mentioned sodium compounds at all. What I have mentioned is that when I was working in the lab industry one of the leaders in that industry had found that the silver compounds released by labs were not environmentally toxic, something I was never able to find refutation of, and that there is a huge amount of hysteria surrounding this issue.
The dumping of silver compounds from photo labs ended in the 1980s, the hysteria lives on.
And for the record, I'm not telling anyone to dump fixer down the drain, but I am suggesting tempering hysteria with reason, something that appears to be of significant difficulty.

[Benz3ne]

Actually, I've not mentioned sodium compounds at all. What I have mentioned is that when I was working in the lab industry one of the leaders in that industry had found that the silver compounds released by labs were not environmentally toxic, something I was never able to find refutation of, and that there is a huge amount of hysteria surrounding this issue.
The dumping of silver compounds from photo labs ended in the 1980s, the hysteria lives on.
And for the record, I'm not telling anyone to dump fixer down the drain, but I am suggesting tempering hysteria with reason, something that appears to be of significant difficulty.

You're right, you haven't. I'm juggling posting here with work in the lab, so sodium compounds on the brain.
It doesn't read as though you're not telling anyone to dump fixer down the drain, just fyi from an outsider's perspective.

My point stands that you've mentioned various silver complexes (amended above) interchangeably where it's not correct to.