[Alt-photo] Dichromates and Septic System?

Jacques Kevers jacqueskv at gmail.com
Thu Feb 15 16:23:05 UTC 2018

The info about how to dispose of dichromate waste certainly is interesting,
but will become rapidly superseded here in Europe (as soon as our current
individual reserves will be gone), as the purchase, import, use and even
simple possession of dichromates now is prohibited in all of the E.U. ...

Jacques Kevers
Beau Site
Première Avenue 7
B-1330 Rixensart
+32 2 653 56 02

2018-02-15 16:41 GMT+01:00 Diana Bloomfield via Alt-photo-process-list <
alt-photo-process-list at lists.altphotolist.org>:

> Thank you!!  Very helpful.
> On Feb 15, 2018 10:30 AM, "Richard Sullivan" <sullivan8486 at gmail.com>
> wrote:
> From Bostick & Sullivan C. 2002Gum Dichromate Green
> Types of chromium
> Gum printing involves the use of hexavalent chromium. This form of chromium
> has achieved a bit of notoriety since the release of the movie Erin
> Brockovich. Yes this is the same form of chromium that Ms. Brockovich was
> dealing with in the film.
> Some caveats: It is dangerous and can be carcinogenic. However, remember
> the Borckovich film was dealing with industrial usage levels. The film was
> dealing with tons and tons being willy nilly dumped into the local soil and
> going into the water supply. Pretty scary. We are dealing with grams.
> First, let me say that some of the data and information being passed on
> around on gum printing is based on industrial exposures levels of chromium
> compounds. In days gone by men would roll up their sleeves and dunk hides
> into vats of the solution for tanning and do this all day long or they
> would work in chrome plating shops where it was not uncommon to roll up one
> sleeve and reach down in a vat of it  to fetch a piece which had fallen to
> the bottom. These men's arms would literally turn orange which they washed
> off with some bisulfite. This does not happen today in most places though
> I'd not be surprised to know that in some developing countries it is still
> being done this way. It is a good idea to have an MSDS sheet handy, your
> seller should provide one. In reality, MSDS sheets are always worst case
> condition. If you read a number of them you will see that they are almost
> all the same and are based on a formula. For instance it lessens any
> liability and most say that for any skin contact you should seek medical
> aid immediately after flushing with water. Because of this I think they in
> effect are causing more harm then good as people become accustomed to
> thinking everything is dangerous and will develop a "Oh what the hell"
> attitude.
> Ok, you don't want to give up gum printing and you want to be a good
> environmental citizen so what do you do? With gum printing we are not going
> to dealing in these extremes. Hexavalent chromium can however be dangerous,
> no doubt about it, but it can be dealt with safely.
> First off let's deal with our personal safety. Gloves are essential. Of
> course follow common sense rules. Always keep solutions in well marked
> containers, never store in anything looking like a food container and NEVER
> store near food or in a refrigerator.
> This issue is in my mind the most dangerous aspect of gum printing chromium
> compounds!
> A paper face mask is needed for weighing and mixing the dry crystals. If
> drying the coated paper with a hair drier or fan a face mask would be a
> good idea. During development a mask is not needed as the compound will not
> become breathable when in solution but gloves are essential. It is not
> volatile like acetone, or gasoline.
>  Incidental contact should be avoided but small splashes on the hands arms
> or face only need to be rinsed off thoroughly and do not require a visit to
> the emergency room.
> Never ever mix with any compound unless you specifically know it is safe to
> do so. The chromium compounds are powerful oxidizers and with combination
> with a fuel source can cause fire or explosion. The Oklahoma Bombing was
> done by combining a fuel source Diesel fuel with an  a common fertilizer
> (an oxidizer.)   Do not combine with any powdered metals like aluminum or
> iron. Do not combine with any hydrocarbon or volatile fuel compound. Do not
> combine with glycerin.
> The gum printing chromium compounds  are safe when stored properly.
> Collecting the nasty stuff
> This step is particularly important if you are on a well and a septic
> system! That is not to say you should be dumping it into your municipal
> system however.
> The first step is to collect your gum developing run off. You may wish to
> collect this in a large tank or plastic garbage can.
> Converting to trivalent
> Add sodium bisulfite, sodium sulfite, plain old spent fix or sodium
> thiosulfate to the solution. The solution will turn from orange to green.
> Keep adding until there is no more green color and add a bunch more to
> insure all is converted.  It is now a much safer trivalent chromium
> compound.
> Making a precipitate of the chromium
> You want to go a step further. Now add an alkali to the solution in the
> tank or garbage can. You can use sodium hydroxide (plain old Draino works
> fine.) or sodium carbonate or potassium carbonate. After the alkali is
> added  the chromium now is converted to chromium hydroxide which can be
> filtered out.
> Building the filter thingy.
> I have not attempted the filtering step on a large scale as I have not gum
> printed in several decades. I have however filtered tanks of solution many
> times before with this system. Here's how I would approach the problem:
> I'd start with a small pond pump. Not a real tiny one but one that costs
> about $50.00 would be large enough to handle a 50 gallon plastic garbage
> can. Now buy a house size water filter. They are available in nay hardware
> store and are usually blue plastic and are about the size of a 1 liter
> Pepsi Bottle and cost about $15.00. Next buy the fittings necessary to
> attach the blue plastic house water line filter to the outlet of the pond
> pump directly. Install a cheap paper filter into the housing ($3.00 -
> $5.00). Do not use the expensive charcoal filter cartridges as they are a
> waste of money in this case.
> Filtering the tank
> Dunk the pond pump with the filter directly attached into the tank. Plug it
> in and let it run overnight. It will intake and discharge into the tank.
> This is less efficient than filtering from one tank to the next but the
> plumbing is far simpler. I've used this system to filter stuff in tanks in
> the past. You may have to change the filter 2 or three times depending on
> the amount to filter out.
> Disposing of the wet nasties
> When finished put the filters  in a 1 gallon zip lock bag and label the
> bags "Chromium Oxide Waste." Take the bag to your  hazardous waste disposal
> center.
> --End--
> On Thu, Feb 15, 2018 at 6:54 AM, David Robertson via Alt-photo-process-list
> <alt-photo-process-list at lists.altphotolist.org> wrote:
> > Adding a reducing agent like sodium sulphite (or bisulphite) would reduce
> > the chromium to the 3+ oxidation state. Chromium (III) is much less toxic
> > than chromium (VI). I always do this before disposing of any hexavalent
> > chromium compounds.
> >
> > David
> >
> >
> > > On 15 Feb 2018, at 13:46, Diana Bloomfield via Alt-photo-process-list <
> > alt-photo-process-list at lists.altphotolist.org> wrote:
> > >
> > > I'm sure this question has been asked and answered before, but I can't
> > > locate it.  A friend who wants to learn gum printing asked about what
> to
> > do
> > > if you have well water?  Does anyone know the answer?  I thought there
> > was
> > > something you could add to a septic system that neutralizes the
> > dichromate
> > > somehow??  Thanks!
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