Chemistry disposal

Drew B. · Nov 27, 2006

I got this info from someone and want to check it accuracy:

Pour exhausted fixer over steel wool pads, let solution sit for 24 hours (the silver in the fixer has a chemical reaction with the steel wool and the silver clings to the wool, leaving a simple salt solution) and pour off the solution (flushed down the drain w/a good mix of water)

For the developer and stop, neutralize them both by mixing them and dumping down the drain w/lots of water.

What does this sound like to our apug experts?

drew

reellis67 · Nov 27, 2006

That's basically what I've read many, many times, but I've never seen any reference to anyone having scientifically tested this procedure to see if the process is complete or not or anything about how many steel wool pads are needed per volume of fixer...

- Randy

Photo Engineer · Nov 27, 2006

Steel wool is the common method used to reclaim silver from hypo. It is more like Iron wool, as that is what you get in a Brillo pad. Steel is very resistant to the exchange unless it is very low grade steel.

Mixing developer and stop is an effective method of neutralizing the developer and stop both and is one more argument in favor of using a stop bath BTW.

The biggest problem with both fixer and developer is the COD and BOD or "Chemical Oxygen Demand" and "Biological Oxygen Demand". Basically, this means that the chemicals in photo solutions deplete the oxygen in the water and make it more difficult for aquatic life to live in such water.

PE

Mike Wilde · Nov 27, 2006

Yes, steel wool is a commercially used option

Silver recovery is actually done this way - the old yelow father actually, and may still, marketted this affair. There were usualy two about 5 gallon drums packed with steel wool connected in series.

I usually use old windshield washer antifreeze jugs - they are plentiful here - and stuff a few wads of steel wool through the throat. The spent fixer gets poured in once it is too long in the tooth, or exhausted in the tray. It accumulates all winter in that manner. In the summer, the top of the jug effluent is poured into a surplus food service stainless steel tray and set in the sun on top of the back yard shed where it gets sun, but not rain, to evaporate. The bottom tray slime is combined with the drippings from the storage jug bottom, and the small jar is labelled and dropped off at the local hazardous waste site.

Developers are alkaline, so, yes, acid stop bath will tend to neutralize the mixed product. It may not cut its BOD - basic oxygen demand, though. The simplest way to allow this to be looked after is to the spent developer in a tray overnight. Once they are good and brown most of the BOD of the developer has been aerially oxyidzed.

rpsawin · Nov 27, 2006

I am interested in this as well. I am building out my darkroom this spring and I thought I would use a 5 gal bucket of sand with holes along the bottom edge to pour chemicals into. Once the solutions perked thru the sand the "treated" water would come out the bottom. I plan on setting this up in a corner of the lawn area. Based on usage I plan on bagging the bucket/sand and dropping it off at the hazardous waste site.

Any comments would be appreciated.

Bob

Ole · Nov 27, 2006

Sand won't do anything, except perhaps remove any solid matter.

Steel wool works by replacing the dissolved silver with dissolved iron on a 1:3 basis - 3 Ag+ + Fe -> 3 Ag + Fe(3+).

The "nasties" in developer are (1) high pH, and (2) reduction potential. Exactly the thing that make it work as a developer. Neither will be affected by a sand filter. The pH can be neutralised by adding acid (as in stop bath), and the reduction potential can be reduced by oxidation. On the other hand the oxidation products of developers can be just as nasty as the original chemicals! The best way to dispose of developer is to allow it to evaporate to a thick sludge, and hand that in at a hazardous waste site. The second best way is to dilute it a lot and pour it down the drain...

Amund · Nov 27, 2006

Ole;397878The second best way is to dilute it a lot and pour it down the drain...[/QUOTE said:
When I don`t use my Jobo paper drum when developing, I use it to pour all chemicals+water in. So prewet, used developer, stop, fix and all the water for washing the film ends up there. Is that diluted enough?

Ole · Nov 27, 2006

Amund said:
Is that diluted enough?

Yes.

At least in areas where everything ends up in the ocean...

Drew B. · Nov 27, 2006

Ole said:
Yes.

At least in areas where everything ends up in the ocean...

What are your thoughts for an area, such as Cape Cod, surrounded on three sides by ocean, where there is one fresh water aquifer for the 13 or so communities? Also, most homes/businesses are on septic systems....no public sewer systems. So, our waste water, and everything that goes out our drains with it, is going out into an individual leaching field that is (supposedly) about 100' from our wells. (no public water in my village)

Actually, I bet throwing down the drain, using some sort of the above mentioned processess, spent chemicals is better than those idiots who put chemicals constantly onto their laws and gardens!

see what we're up against here....? I want to make sure I do it right and will also check with local officials on what they consider a viable option.
drew

Ryuji · Nov 27, 2006

Ole said:
The "nasties" in developer are (1) high pH, and (2) reduction potential. Exactly the thing that make it work as a developer. Neither will be affected by a sand filter. The pH can be neutralised by adding acid (as in stop bath), and the reduction potential can be reduced by oxidation. On the other hand the oxidation products of developers can be just as nasty as the original chemicals! The best way to dispose of developer is to allow it to evaporate to a thick sludge, and hand that in at a hazardous waste site. The second best way is to dilute it a lot and pour it down the drain...

The alkalinity of most standard film and print developers is not high enough to easily damage the sewer pipes (acid can be more dangerous in this regard). The danger is when undiluted developer stays in the pipe and traps for a prolonged period of time. If developer is dumped first, followed by other chemicals and then some water, traps and peripheral pipes may be flushed effectively.

Oxygen demand is best dealt with (1) use only necessary amount of developer, and to exhaustion, (2) leave exhausted developer in open tray for a few days or partially filled, uncapped tanks for several days. In order to effectively reduce COD, the developer has to be nearly completely oxidized. That is, VERY dark color, not just brown.

In my view, in small scale darkrooms in areas where sewer system is well developed, it is best to focus on the (1) part. If you cut down the amount of developer waste by 20%, that's 20% saving of your oxygen demand. To do the same in the (2) approach, it'll take a lot of time.

Oxidation products of ascorbic acid are not nasty. Some of the products may smell, but not as badly as oxidized/exhausted HQ developers. This is another reason to use ascorbate-based developers. (Note: I'm not necessarily promoting my products here. I'm perfectly happy to hear individual photographers mixing DS-10, DS-14, neutral fix, etc. and save money. But on the other hand since late May Silvergrain products are being used by institional users such as pro labs, art schools, some government agencies and others, who had no way to mix chemicals from bulk raw agents. I think those users now use considerably less hydroquinone-based products.)

rpsawin · Nov 27, 2006

Ole said:
Sand won't do anything, except perhaps remove any solid matter.

Steel wool works by replacing the dissolved silver with dissolved iron on a 1:3 basis - 3 Ag+ + Fe -> 3 Ag + Fe(3+).

The "nasties" in developer are (1) high pH, and (2) reduction potential. Exactly the thing that make it work as a developer. Neither will be affected by a sand filter. The pH can be neutralised by adding acid (as in stop bath), and the reduction potential can be reduced by oxidation. On the other hand the oxidation products of developers can be just as nasty as the original chemicals! The best way to dispose of developer is to allow it to evaporate to a thick sludge, and hand that in at a hazardous waste site. The second best way is to dilute it a lot and pour it down the drain...

Ole,

Thanks. That's great information. I checked on the city's waste disposal web page and the city treats photo processing chemicals as part of the waste water treatment process. To be safe I will batch together, and then highly dilute with water, the chemicals when I dispose of them.

Thanks again for the information.

Bob

Ryuji · Nov 27, 2006

rpsawin said:
Thanks. That's great information. I checked on the city's waste disposal web page and the city treats photo processing chemicals as part of the waste water treatment process. To be safe I will batch together, and then highly dilute with water, the chemicals when I dispose of them.

In many areas it goes similar to your city, but the regulations vary a lot depending on the area. It also varies if the darkroom is for business.

Exhausted fixers are best disposed of by chemical treatment plant to recover silver, which is a limited resource.

Other waste water that should be checked separately are bleaches and selenium toner. Most common b&w bleach is ferricyanide (hexacyanoferrate) and this is environmentally hazardous. Selenium toner, when diluted, is usually safe to dump in coastal areas (because the soil naturally contains selenium compounds) but this may be regulated depending on the area. Eastman Kodak recommends to save spent selenium toner solution for chemical disposal, regardless of quantity.

removed account4 · Nov 27, 2006

drew

here in ri, the narragansett bay commission and local sewer authorities
are very strict about disposal of photo chemicals.
i use a waste hauler ( if you want his name pm me he picks up stuff on the cape )
who gives me either a 30 gallon or 15 gallon drum.
i fill the drum with my spent chemicals and he hauls it
away.

i think it cost me about $100 for 3 years worth of chemicals to be hauled away ... and i have the peace of mind knowing i didn't dump it down the drain ...

good luck!
john

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