discarding chemicals

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Where can I get information on discarding my chemicals, i.e., which ones are safe to go down the drain versus ones dangerous to the pipes?

-- Amanda (alwsdrmg@tstar.net), January 24, 2000

Answers

Amanda:

Several publications are available from Kodak. Try: http://www.kodak.com/global/en/service/library/environmental/additiona l.shtml

The one titled "Environmental ?? for Amateur Photographers" (in Acrobat format) gives you exactly what you are looking for.

Walt

-- Walt Bowen (Walt.Bowen@jhuapl.edu), January 24, 2000.


Basically all photo chemicals can go down the drain, even with a septic system. It is best to mix them and dilute them before disposal. All are biodegradable.

Also, it is best to recover the silver from the fixer before disposal, even though the form of the silver in fixer is not that bad. Porter's (www.porters.com) carries a silver recovery unit for $35. It is an electrolytic unit with a replaceable cell ($15). You return the used cell to the mannfacturer and they recover the silver and pay you for the silver (minus processing costs).

It can also help to fully oxidize the chemicals before disposal. That is, put them all in a bucket and let them sit for a while before pouring out. To speed this up, use and aquarium pump and air stone. The biggest impact on the sewage stream that photo chemistry has is the oxygen demand, so pre-oxidizing minimizes that impact.

Check out this site:

http://www.cherryvalley.com/terragreen/

-- Terry Carraway (TCarraway@compuserve.com), January 25, 2000.


I would hesitate to advise anyone to pour all of her/his photographic waste materials down the sewer. Not so much for fear of damaging the tubing, but because some of the stuff is highly toxic. Of the developing agents most are toxic, some even potentially carcinogenic. All of them are reducing agents, which leads to their taking oxygen out of the water. This, in turn, adversely affects the bacteria at the wastewater plant, which are supposed to break down the chemicals. Therefore, the least one should do before disposing of old brown is to allow the developer to fully oxidise. But even then, there are still hazardous chemicals in it, and I prefer to bring my old developer to a toxic-waste disposal plant. (This is easy in Germany because there are collection points, and they collect the stuff free of charge. I don't know in which other countries there are similar services.)

Stop baths are not usually a problem as the effective agent is citric acid or acetic acid, both of which are non-toxic. There is a certain contamination with developer, but this is low-level, and disposing of this in an incineration plant would, due to the energy this requires, cause more damage to the environment than pouring it down the sewer.

Fixers contain quite some silver (up to 8 g per litre when fully used). Although the thiosulphate complex is not highly toxic (see Kodak publications referenced in an earlier post), it would be a pity to lose all that silver forever. There are several ways to recover the silver (again, see Kodak), and one should try to make good use of one of them. This not only because of its potential environmental effects, but also because silver-based photography will become more and more expensive as silver becomes less and less abundant.

To my knowledge, hypo eliminators are, as a rule, rather harmless compounds, and the used baths do not contain silver in significant quantities. These can, therefore, be drained.

When it comes to toners, selenium is worth mentioning as it is highly toxic and also carcinogenic. There is no biodegradation. Therefore, I would not drain selenium toner. It ought to go to a toxic-waste disposal plant.

Thiocarbamide is carcinogenic, and I don't know whether it is degradable. So I think what has been said for selenium basically applies here, too.

Sulphide (from the stinking sepia toner) is not a problem as far as I know.

So much for theory. I know that it may be difficult, or even impossible, to properly dispose of used chemicals, and it is certainly much less convenient than just pouring everything in the sewer. Also, the quantities to be disposed of from amateur labs are small when compared to the industrial scale. But we cannot, on the one hand, blame the large companies for ruining our environment and do the same on our own doorstep. It is not only the quantity that matters, but also the principle.

I find that the decision should be made with full awareness of the potential harm done rather than on the basis of an undifferentiated statement that all is fine.

-- Thomas Wollstein (thomas_wollstein@web.de), January 26, 2000.


>> Sulphide (from the stinking sepia toner) is not a problem as far as I know.

I'm not a chemist, but I understand the gas that stinks (hydrogen sulphide) is more poisonous than hydrogen cyanide. But it stinks so badly that we are unlikely to inhale a dangerous quantity.

-- Alan Gibson (Alan.Gibson@technologist.com), January 26, 2000.


Alan

We were talking about disposal problems, not personal health and safety.

Hydrogen sulphide (the foul-egg smell) is extremely hazardous, and what makes it worse: You get accustomed to the smell, which means that having spent some time in the contaminated atmosphere, you won't smell it any more. When you have inhaled a sufficient dose, you will pass out, possibly forever. That's why they always recommend to use the toner in rooms with sufficient air exchange.

Thiocarbamide, otoh, doesn't smell, but is potentially carcinogenic. So it seems you have to choose between the immediate danger and one lying far in the future.

When we start talking about personal health and safety, we will quickly find that practically all photographic chemicals (except maybe gelatin if it doesn't come from BSE cows) are hazardous (though to different degrees).

-- Thomas Wollstein (thomas_wollstein@web.de), January 27, 2000.



I quite agree with you Thomas. I just didn't want to leave an entry in the forum that might lead people to think that hydrogen sulphide was 'safe'.

-- Alan Gibson (Alan.Gibson@technologist.com), January 27, 2000.

Alan and Thomas,

You are both sort of right. Hydrogen sulfide is highly toxic and a sufficient concentration is deadly.

The problem is not that you get used to it, but that in high concentrations hydrogen sulfide paralyzes the sense of smell. So if it strong enough to cause harm, you can't smell it at all, virtually immediately.

So if you can smell it, it is a low enough concentration to not be a large hazard. But it is still not good for you, besides smelling VERY bad.

Also Thomas, most all photo chemicals are biodegradeable (I do agree with you about selenium toner). Most ALL waste has an oxygen demand, which is why most sewage treatment includes some for of aeration, either active mixing or large surface area ponds. It does help to reduce the oxygen demand of the waste stream, but the home darkroom is a very small amount contributor to the waste stream. But every little bit helps.

Also home use amounts of photo chemistry is OK to dispose of in a septic system.

-- Terry Carraway (TCarraway@compuserve.com), January 27, 2000.


I work as an operations supervisor at a wastewater treatment facility. Unless you are producing a few thousand gallons of photographic effluent a day, dumping down the sewer has no detrimental effects at the plant. Most plants have such high rates of flow that dilution is enormous. In a septic system the same is true. A half a gallon of dektol or fix is nothing compared to the 100+ gallons per person per day normally used in most industrialized countries. So don't worry about it. James

-- Mr.Lumberjack (james_mickelson@hotmail.com), January 28, 2000.

James,

Exactly.

We contacted the local wastewater treatment facility over a client who wanted to know about disposing of about 300 gallons of highly alkaline solution (pH 14) every two months. Their comment was they would never even notice. I forget how many thousands of gallons per minute they handled, but it got my attention.

-- Terry Carraway (TCarraway@compuserve.com), January 29, 2000.


Not to dismiss environmental concerns or to abdicate personal responsibility, but a large industrial facility dumps more toxins into the environment in one minute than the average "home" darkroom worker does in a lifetime. Besides, if you eat animal products ("meat", dairy, etc.), as most people in this land do, you are responsible for more damage to the environment than you will ever cause by using photo chemicals. So put it in perspective.

Anyway, you ask about which are safe to the *pipes", not to the environment. Well, that depends on what your pipes are made of. (PVC is probably the most chemical resistant; iron, copper and lead the least.) Some photo chemicals can corrode metallic sinks, drains and pipes, even in diluted form. Flushing with a lot of water is a good idea.

-- Peter Hughes (leo948@yahoo.com), February 01, 2000.



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