Chemistry disposal? What do folks actually do with spent chemistry?

Kirk Keyes · Apr 20, 2008

Don12x20 said:
Lets see if we can answer that one...

Two methods -- and whichever one you choose has to work on ALL the incoming sewage...you don't know where the darkrooms are...

Well, actually, you need the silver to be ionic to reclaim it with the methods you described, and in fact, there will be very little ionic silver by the time it reaches the Sewage Treatment Plant. It will be nearly all chloride or sulfide, both extremely insoluble and therefore unavailable for recovery by the methods you mention.

Don12x20 · Apr 20, 2008

Kirk Keyes said:
Well, actually, you need the silver to be ionic to reclaim it with the methods you described, and in fact, there will be very little ionic silver by the time it reaches the Sewage Treatment Plant. It will be nearly all chloride or sulfide, both extremely insoluble and therefore unavailable for recovery by the methods you mention.

If insoluble why the worry? Doesn't make sense that anyone would be concerned at all...the silver wouldn't be active

No matter - I have two good friends that are wastewater engineers locally - one at the Hillsboro plant(s - there are 3) and one with City of Portland.

David William White · Apr 20, 2008

Thanks, Don12x20, for the numbers on the EPA threshold of 5mg/litre for silver.

dancqu · Apr 20, 2008

Kirk Keyes said:
Well, actually, you need the silver to be ionic to reclaim
it with the methods you described, and in fact, there will
be very little ionic silver by the time it reaches the Sewage
Treatment Plant. It will be nearly all chloride or sulfide,
both extremely insoluble and therefore unavailable for
recovery by the methods you mention.

Some distinction should be made twixt silver in the water
and the silver content of the sludge. Silver sulfide is Extremely
insoluble, much less so than the chloride. Sewage abounds in
sulfur containing compounds so one would expect the sulfide
of silver to concentrate in the sludge.

Two other approaches might be used to bring fixer silver
levels to near zero; Sulfide the fixer and Destroy the fixer.
Each method will produce a precipitate of silver sulfide.
As a usual darkroom technique I'm not sure either
would be practical although the chemistry costs
should be low and the methods safe. Dan

Paul Verizzo · Apr 20, 2008

2 centavos

My father, working as a professional in our old home with a septic system, never had a problem with the latter. He DID reclaim silver by some kind of resiny stuff on a wooden core. But everything else went into the tank.

Water coming out of the Rocky Mountains is often over EPA limits for silver and other metals. The Kodak plant in Windsor, Colorado had to clean their discharge waters so that they were cleaner than they came in!

As cute as "The solution to pollution is not dilution" may be, it is factually incorrect. Many substances are irritants or toxic at one level of concentration and not at another. Think vinegar and glacial acetic acid. A gazillion silver molecules coming down the sewage plant in one batch might indeed cause bacteria death and create downstream concerns, but the same number of molecules released over time wouldn't be noticed.

What a small home darkroom might contribute to sewage plant problems or the environment pales compared to other, larger problems. If you are doing enough work that you are a pollution source, you are probably reclaiming the silver anyway.

Paul Verizzo · Apr 20, 2008

dancqu said:
Some distinction should be made twixt silver in the water
and the silver content of the sludge. Silver sulfide is Extremely
insoluble, much less so than the chloride. Sewage abounds in
sulfur containing compounds so one would expect the sulfide
of silver to concentrate in the sludge.

Two other approaches might be used to bring fixer silver
levels to near zero; Sulfide the fixer and Destroy the fixer.
Each method will produce a precipitate of silver sulfide.
As a usual darkroom technique I'm not sure either
would be practical although the chemistry costs
should be low and the methods safe. Dan

Sounds like a good idea. How would you do that? (Chemistry thinking cap won't start.)

ozphoto · Apr 21, 2008

My mechanic offered to dispose of my chemical waste when he takes his oil etc to his waste depot. I just collect it in a 50L container and take it down to him. Easy and saves me paying to dispose of it.

-Nanette

dancqu · Apr 21, 2008

Paul Verizzo said:
Sounds like a good idea. How would you do that?

One method practiced by a few is to let the
fixer go very bad via oxidation; a few shallow
tubs of used fixer soaking up oxygen.

I've used H2O2, hydrogen peroxide, producing
a brownish flocculent precipitate of silver oxide
or hydroxide. House hold bleach may do but
will not recommend without investigating.

A solution of sodium sulfide should do well.
Neutralize or make alkaline the fix prior to
adding. An acid fix otherwise may produce
H2S, hydrogen sulfide gas. I'll give that a
test in the next few days then post back.
I'd think Na2S very inexpensive. Dan

Marco B · Apr 21, 2008

Nsurit,

If you really want to make a difference to this planet, why not persuade your local city council to setup a proper municipal chemical waste disposal unit for it's inhabitants???

I again and again am surprised that a big country like the US, and it's big cities like your own city Houston, don't seem to have proper facilities for this, as your type of question is coming up each few months here on APUG from US photographers...

Like in Germany and Denmark, we here in the Netherlands can dispose (or better said MUST dispose) of the chemicals via our local municipalities (chemical) waste unit, that also handles stuff like electronic waste, asbestos and small amounts of demolition waste. We pay for all that through our municipalities and governmental taxes.

Paul Verizzo · Apr 21, 2008

Marco B said:
Nsurit,

If you really want to make a difference to this planet, why not persuade your local city council to setup a proper municipal chemical waste disposal unit for it's inhabitants???

I again and again am surprised that a big country like the US, and it's big cities like your own city Houston, don't seem to have proper facilities for this, as your type of question is coming up each few months here on APUG from US photographers...

Like in Germany and Denmark, we here in the Netherlands can dispose (or better said MUST dispose) of the chemicals via our local municipalities (chemical) waste unit, that also handles stuff like electronic waste, asbestos and small amounts of demolition waste. We pay for all that through our municipalities and governmental taxes.

Marco, most communities here now have some kind of Hazmat collection point, and/or they have annual collection drives. Bring your lead, your DDT, your pollonium, y'all come now, heah? Unfortunately, the are often distant and you must cart the crap to the site. Obviously, this is a hell of a lot better than 20 years ago, but still not perfected.

I have hundreds of pounds of hazmat stuff, mostly paint and related, from cleaning out my father's garage. I will have to borrow a trailer to put it all on and drive 20 miles to the collection point.

Used motor oil, BTW is collected at most DIY auto parts stores.

tim_walls · Apr 21, 2008

Marco B said:
Nsurit,

If you really want to make a difference to this planet, why not persuade your local city council to setup a proper municipal chemical waste disposal unit for it's inhabitants???

I again and again am surprised that a big country like the US, and it's big cities like your own city Houston, don't seem to have proper facilities for this, as your type of question is coming up each few months here on APUG from US photographers...

Like in Germany and Denmark, we here in the Netherlands can dispose (or better said MUST dispose) of the chemicals via our local municipalities (chemical) waste unit, that also handles stuff like electronic waste, asbestos and small amounts of demolition waste. We pay for all that through our municipalities and governmental taxes.

I have to say I was surprised to learn that here in the UK my local council will arrange collection of hazardous chemicals - although I normally take such things to my local tip. (Although apparently I'm meant to call it a "Household Waste Sorting Site" rather than a 'tip', these days.) I imagine many places actually have such arrangements, but people don't know about them.

The bit that really surprised me was that in their leaflet on what materials they provide disposal advice for/arrange collection of, there was an explicit entry for "Hobby chemicals (photo developing materials, model fuel)."

Antje · Apr 21, 2008

I just take everything (fixer and developer) to the local waste sorting site. Actually, access has always been free here, and I haven't been charged for disposing of my stuff, either. But I only have a two or three 5 l bottles each every few months. It's really convenient, we just drop in there on our way to the bakery on saturdays, and that's it. The bottles are the ones the distilled water comes in. Two birds with one stone.

Antje

Kirk Keyes · Apr 21, 2008

Don12x20 said:
If insoluble why the worry? Doesn't make sense that anyone would be concerned at all...the silver wouldn't be active

No matter - I have two good friends that are wastewater engineers locally - one at the Hillsboro plant(s - there are 3) and one with City of Portland.

I know a person at both Hillsboro and City of Portland, but they work in the labs for the STPs.

There is still some concern environmentally from precipitated silver as sulfide or chloride, I had a boss with an entire book on the subject. Never got past skimming the contents...

But most precipitated material from an STP is collected (called "biosolids") and is either dumped in landfills or, more recently, used as fertilizer for non-food crop fields. And the biosolids are tested for these metals to make sure they are not too high in anything that may be hazardous before being applied to a field. At least around this part of the country.

Mmmm.... biosolids. Glad I don't have to test that stuff anymore. You'd be surprised by the things that make through a sewage treatment plant...

dancqu · Apr 22, 2008

Ammonia Fixers and Bleach Are a Dangerous Combination

dancqu said:
v
House hold bleach may do but will not
recommend without investigating. Dan

Is was reminded that household bleach and
ammonia mixed together are a Hazardous mix.
Avoid with rapid fixers. Likely safe when used
with sodium fixers. Dan

gbroadbridge · Apr 22, 2008

Here in Sydney, when I asked Sydney Water Corp. about dumping used chemistry down the sewer they said "photochemicals in the quantities used in a home darkroom are insignificant and they may disposed of into the sewerage system. Commercial photo laboratories must perform silver recovery before dumping the waste into the sewerage system.. Reclaimed silver should be recycled".

Erik Hartmann said:
Here in Denmark, we have the same arrangements as in Germany.... I drop my chemical waist in 2 1/2 or 5 litters plastic containers, mark them with what is in and place them in a locker in the apartment building , where I live... Then it automatically taken care of.... this service is free....

gbroadbridge · Apr 22, 2008

Down under, they're called 'Waste Management Centres'. Unfortunately, as they've been privatised, the minimum charge for waste disposal is $27.50 whether it's for one litre or a carload.

As Sydney Water tell me that home darkroom quantities of photochemicals are insignificant to their waste recycling system, I just pour everything down the drain.

Graham.

tim_walls said:
I have to say I was surprised to learn that here in the UK my local council will arrange collection of hazardous chemicals - although I normally take such things to my local tip. (Although apparently I'm meant to call it a "Household Waste Sorting Site" rather than a 'tip', these days.) I imagine many places actually have such arrangements, but people don't know about them.

The bit that really surprised me was that in their leaflet on what materials they provide disposal advice for/arrange collection of, there was an explicit entry for "Hobby chemicals (photo developing materials, model fuel)."

Dennis S · Apr 30, 2008

chemical disposal

Found a hazmat disposal site within walking distance from my place. It's in an industrial area and safe. Take a walk there with my dog and camera nice outing for afternoon project.

fschifano · May 1, 2008

Dave Miller said:
I wonder why the sewage works doesn't have a silver recovery unit? :confused:

Maybe because there's not enough there to be bothered with???

David William White · May 1, 2008

Exactly -- micrograms per 1000 litres.

Andy K · May 1, 2008

I just flush my chemicals. I figure the cleaning agents I use in the kitchen and bathroom almost daily are probably far more environmentally unfriendly than a couple of litres of dev and fix every couple of weeks or so.

Andrew Moxom · May 1, 2008

Same here.....I empty all of my trays into the bowl, and then flush ONCE to save water. If the timing is right, I might add some 'other' components, but that depends on how much I drink during a darkroom session. As Andy K says, the chems like bleach, and cleaner are way more toxic than fixer, stop, and dev.

Absinthe · May 1, 2008

So silver is the big problem in the chemical soup we dispose of? Are all the rest of them safe to dump and go through the processing stations?

CBG · May 1, 2008

In ordinary home volume BW processing with run-of-the-mill solutions the concensus is that silver is the one bad guy that one should take control of. If you are doing exotic processes, or high volume, maybe other items might need to be controlled.

C

Absinthe · May 1, 2008

If you just evaporate it outside can you just dispose the solid in household trash? (bit sewer)

Christopher Walrath · May 2, 2008

Down the municipal drain.

Chemistry disposal? What do folks actually do with spent chemistry?

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