Chemical disposal by evaporation

ian the framer · Sep 15, 2010

I have a septic tank where I live so am concerned (as are many) about disposal of waste chemicals.
It is very hot here during the summer so I thought of evaporating things.

I have a large tray 30 inches (760mm) square, I have made a lid from mosquito netting to stop any thing landing/climbing or jumping in. I intend to put small quantities of mixed developer (xtol or ID-ll) mixed with stop bath in here and leave to evaporate. Any residue left can be collected and stored until there is sufficient to merit professional disposal. Fixer will be treated in a similar way after pre-treatment with a silver magnet.

So. Two questions.

1. Has anybody else tried this with any degree of success or failure?
2. Can any body see a downside to this?

I must stress this is only a hobby and the quantities are fairly small

Ian

Ian Grant · Sep 15, 2010

This is done for commercial disposal in some parts of the world, although they use faster methods to super concentrate first - usually reverse osmosis. The residues once dry are heated and fused and become chemically inert. Waste heat from furnaces is used to do the drying.

Your idea should work OK in your location, it's just a bit messy and needs space away from animals & children for the evaporation.

Ian

Wade D · Sep 15, 2010

Not a bad idea although a little messy. Septic systems should be able to digest developer once neutralized with stop bath though. I put small amounts in my septic tank with no problems. Fixer is another story. Even after the use of a silver magnet it could be harmful to the bacteria in your septic system.

Neal · Sep 15, 2010

Dear Ian,

I actively tried this once. It is possible, but unpleasant enough that I gave up. The main value was not having to go to the waste disposal site as often. As I have no trouble getting to the drop-off site at least once each month I just handle it that way. It might be a great way to reduce costs if you are charged by volume at your local site. I am on a septic field as well and don't put any photo chemicals (other than rinse water) down the drain.

Neal Wydra

Mike Wilde · Sep 15, 2010

I don't put the screening on the 12x20 or so ex food service stainless steel tray I use for evaporation, but do put it up under the eaves where it does not catch any rain. Mostly I use it to reduce the volume of exhausted fixer, since that is something I don't put down the drain. It is about 20km round trip for getting to the free HHW disposal site my local government runs next to the ordinary transfer staion thta takes stuff to the landfill, or composting plant. I don't get going in that direction often unless I have a large volume of yard waste, like when I do a spring tidy up of the yard.

For developer disposal an option is to dump it into a bucket and put a fish tank bubbler stone in with it. Mixing the stop bath in to neutralize the pH is a great combination. After a day or two a great deal of the BOD rate of the mix will be gone, and the sceptic should be able to swallow it without any harm to the beneficial microbes.

Gerald C Koch · Sep 15, 2010

Some years ago, Kodak studied the disposal of chemcals for the average home user and found that there were no adverse effects on septic systems. The concern at that time was for the health of the sytem only and not any environmental issues.

removed account4 · Sep 15, 2010

jerry

it isn't what they are saying now ...
http://www.kodak.com/eknec/PageQuerier.jhtml?pq-locale=en_US&pq-path=4218

john

removed account4 · Sep 15, 2010

ian

a company called agmet used to sell
small evaporation units.
it was a hard plastic tank with a thick trash liner
a small heating element on the bottom and a
fan ... it might be easier and less messy to evaporate your chemistry
in a similar fashion instead of large trays ..

Gerald C Koch · Sep 15, 2010

I have been doing a bit of thinking about heavy metals in septic tanks. In the alkaline, anaerobic, reducing environment there will be a lot of sulfide ion present from protein degradation and from sulfate, sulfite, and thiosulfate. Any heavy metals will be converted to insoluble sulfides, for example the solubility of silver sulfide is 1x10-52. None is going to get into the ground water and will remain in the sludge. This sludge is eventually pumped out by companies who treat it as toxic waste.

The only other commonly used toxin would be selenium as SeS. It is sparingly soluble in water but the amount entering the environment from photographers is small compared to that from selenium sulfide shampoos such as Selsun Blue or Head and Shoulders used for dandruff which typically are 2.5% selenium sulfide. How many tons of this stuff go down the drain every year.

Modern papers no longer contain cadmium or lead so these metals are no longer of real concern.

keithwms · Sep 15, 2010

If you have the funds, you can probably pick a rotary evaporator from a lab clearinghouse (labx or such). OR get a simple hotplate for much less, if temp control and uniformity and such isn't critical. But bear in mind that the fumes will not be merely solvents but other more troublesome things as well. In the lab, when we want to concentrate some nasties, we use a hood.

ian the framer · Sep 16, 2010

Thank you all for your imput

I know there are arguments weather it is safe or not to dispose of photo chemicals in a septic tank and am aware that opinion is divided.

My own situation is that we are also close to a river, so my own preference is to avoid disposal in this way

I was mainly concerned if there were any environmental issues regarding evaporation of small quantities, it seems there is nothing significant

I understand the comments regarding the messy issue, but I have plenty of space (and time) where I can do this safely (I could buy another tray or two) water evaporates here very quickly in summer I cannot justify the expense of an evaporation unit.

I think I will give it a try and see how it goes.

Ian

Grif · Sep 16, 2010

I'm on a septic. I'm going to evaporate my fixer, and first wash/rinse after fixing and just drop it at the land fill for household waste. Geeze,,, the volume allowed for non-commercial, I could just jug the all the stuff up in containers and haul it all up there.

The way they want paint and the odd household waste taken care of here is evaporation. I keep any huge cardboard sheets, just pile them up and pour the stuff (whatever) on them.

bobwysiwyg · Sep 16, 2010

Grif said:
The way they want paint and the odd household waste taken care of here is evaporation. I keep any huge cardboard sheets, just pile them up and pour the stuff (whatever) on them.

Is that just latex based paints or oil based as well? Here, we just mix some kitty litter in what ever is left of the latex and when dry/hardened, toss it in with the trash. Oil, on the other hand has to go to the toxic waste collection site.

Grif · Sep 17, 2010

Same for paint and oil. Contaminated oil,,, (chlorine) brake fluid, tapping fluid and so on are different. Engine oil and "clean" oil are separate and recycled.

Chemical disposal by evaporation

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