Pointers about disposal of chems into septic system (or not at all)?

On 3/12/2004 3:06 PM Dan Quinn spake thus:

"Pieter Litchfield" wrote

For B&W only: I have heard that the worst offender is the exhausted fixer
due to silver concentrations. Probably the best way to deal with it is to
accumulate it and then dispose of it through a friendly lab in town. There
are also Kodak filters, but not suitable for very low volumes. There are
inexpensive electrostatic precipitators that bond the silver out of
solution, but they do leave some in solution. And I have heard you can just
pour old fixer into a can with some steel wool and a reaction will bond the
silver to the steel wool for disposal.

I'd love to see perspectives on this. I have a precipitator, but don't know
how effective it is.

PERSPECTIVE

Fixer is loaded with thiosulfate. Thiosulfate might be thought of as
being sulfer sulfite. Oxygen being a stronger oxidizer than sulfer, the
sulfite will be converted to sulfate. So we end up with some sulfate,
silver sulfide, and sulfer.

By the way, you might want to know that most people spell it "sulfur". (The
other word you often spell creatively is often spelled "odor".)


--
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(http://www.transafricaforum.org/)

Will do!

Thanks for all the responses, folks!

Oh yeah, thats the good stuff. Perhaps I can make Special K out of
the remaining fixer.


I can't believe after all these years only one person made that Dell
reference...I must be lucky or something..



On Fri, 12 Mar 2004 09:24:06 -0600, John
wrote:

On Fri, 12 Mar 2004 00:44:55 GMT, Some Dude wrote:

I'm not talking huge quantities- maybe 10 rolls/week.

I have the option of storing dead chems and taking them about 50 miles
every 6 months (or however long it takes) and paying a fee to dispose
of them.

However, if I don't have to and I'm not going to cause any
environmental issues, then of course it'd be easier just to dump the
stuff down the drain...

this is bw dev only. occasional pmk pyro but usually rod, tmax,
microdol and acufine...on top of that sodium sulfite ...usually huge
dilutions 1:100 and greater.

thoughts, opinions?

Pour the developers in a bucket and top with a piece of wire
mesh. Put a brick or something on top and allow them to oxidize
outside and then simply toss it either down the drain or on the local
batch of weeds.

Save your fixer and take that to the local lab which will
gladly recover the silver.


Regards,

John S. Douglas, Photographer - http://www.darkroompro.com
Please remove the "_" when replying via email

Cheers,
-sd
http://www.zoom.sh

On 12 Mar 2004 15:06:47 -0800,
(Dan Quinn) wrote:
....
PERSPECTIVE

Fixer is loaded with thiosulfate. Thiosulfate might be thought of as
being sulfer sulfite. Oxygen being a stronger oxidizer than sulfer, the
sulfite will be converted to sulfate. So we end up with some sulfate,
silver sulfide, and sulfer. Silver sulfide is EXTREMLY insoluable.
If I could find the article again I'd point you to it. Kodak states
that some spent fix in the sewage is OK because the silver is soon the
sulfide.
As we all know the sulfide of silver is the silver to have in a
print for extreme print longevity. But sulfides can be oxidized to the
sulfate and silver sulfate is slightly soluable. Sewage systems
are aerobic.
I can only conclude that Kodak has reason to believe that there is
enough sulfer coming into the system to maintain the silver as a
sulfide. Kodak is saying that silver plus thiosulfate equals
no problem.
That may be true; Kodak is lax where pollution is concerned. Dan


mar1304 from Lloyd Erlick,

In a regular black and white darkroom, I think the
worst effluent is silver. The chemicals making up
our solutions are fairly innoucous. And even the
silver we release is not hugely adverse, as Dan
points out above.

The largest portion of our silver effluent is in
spent fixer. So it's conveniently contained, at
least. There are plenty of photo shops/labs that
will take spent fixer, so dumping it shouldn't be
a necessity. It can accumulate in septic tanks and
fields, eventually making a small problem much
larger. And plenty of urban locations are zoned
for darkroom activities, and permit disposing of
darkroom waste down the drain. In my previous
location, I could have operated an abbatoir or a
fur dressing plant, among other things. There was
a fur dresser across the street for decades. I
used to look into their basement chem lab and see
all the dirty, dusty, grungy scales and bottles.
I'm positively surgical by comparison, you could
eat out of my processing tray if I didn't catch
you.

regards,
--le
________________________________
Lloyd Erlick Portraits,
2219 Gerrard Street East, unit #1,
Toronto M4E 2C8 Canada.
---
voice 416-686-0326
lloyd AT the-wire DOT com
http://www.heylloyd.com
________________________________

"Lloyd Erlick" wrote in message
...
On 12 Mar 2004 15:06:47 -0800,
(Dan Quinn) wrote:
...
PERSPECTIVE

Fixer is loaded with thiosulfate. Thiosulfate might be thought of as
being sulfer sulfite. Oxygen being a stronger oxidizer than sulfer, the
sulfite will be converted to sulfate. So we end up with some sulfate,
silver sulfide, and sulfer. Silver sulfide is EXTREMLY insoluable.
If I could find the article again I'd point you to it. Kodak states
that some spent fix in the sewage is OK because the silver is soon the
sulfide.
As we all know the sulfide of silver is the silver to have in a
print for extreme print longevity. But sulfides can be oxidized to the
sulfate and silver sulfate is slightly soluable. Sewage systems
are aerobic.
I can only conclude that Kodak has reason to believe that there is
enough sulfer coming into the system to maintain the silver as a
sulfide. Kodak is saying that silver plus thiosulfate equals
no problem.
That may be true; Kodak is lax where pollution is concerned. Dan


mar1304 from Lloyd Erlick,

In a regular black and white darkroom, I think the
worst effluent is silver. The chemicals making up
our solutions are fairly innoucous. And even the
silver we release is not hugely adverse, as Dan
points out above.

The largest portion of our silver effluent is in
spent fixer. So it's conveniently contained, at
least. There are plenty of photo shops/labs that
will take spent fixer, so dumping it shouldn't be
a necessity. It can accumulate in septic tanks and
fields, eventually making a small problem much
larger. And plenty of urban locations are zoned
for darkroom activities, and permit disposing of
darkroom waste down the drain. In my previous
location, I could have operated an abbatoir or a
fur dressing plant, among other things. There was
a fur dresser across the street for decades. I
used to look into their basement chem lab and see
all the dirty, dusty, grungy scales and bottles.
I'm positively surgical by comparison, you could
eat out of my processing tray if I didn't catch
you.

regards,
--le
________________________________
Lloyd Erlick Portraits,
2219 Gerrard Street East, unit #1,
Toronto M4E 2C8 Canada.

From what I have read, I'd agree that the big offender (In B&W chemistry) is
the fixer, since that's where most of the silver ends up. My question is
"Assuming that we remove all the silver from the discarded exhausted fixer,
will any of the remaining chemical cause an adverse effect on a septic
system?" While another poster made a point of identifying sulphate and
sulfur, I don't know if the mere existence of these compounds is a problem
in a septic system. Can anyone identify a problem with the remaining
chemical composition of exhausted fixer?

In addition, its important to note that we would dispose of a gallon or so
of exhausted fixer (only when indicated by test) infrequently, while
hundreds of gallons of water flush through the septic system each day.
Dilution of the chemicals is almost instantaneous - I dispose of my
developers and fixers while doing a running water rinse, and that alone will
cause significant dilution even before the septic tank. If the exhausted
developer is cleansed of silver, is there any other impact of gradual (1 qt
per darkroom session) disposal over time, for example?

Septic systems are anaerobic - there is no oxygen atmosphere, and oxygen
dependent reactions may behave quite differently. What impact does this
have on the chemistry?

As a final comment - if you own a septic system, be sure to have it serviced
(sludge pumped) once every 3 - 5 years for a modern design. They get
expensive to repair if the leachfield becomes plugged! I have never had a
problem with mine for that reason (knock on wood). Where I live, the pumped
sludge has to go through the municipal tertiary sewage plant, where heavy
metals are removed. However, I think that taking your accumulated fixer to
a commercial lab chemical processor is still the environmentally safest bet.

Pieter Litchfield wrote:


From what I have read, I'd agree that the big offender (In B&W chemistry) is
the fixer, since that's where most of the silver ends up. My question is
"Assuming that we remove all the silver from the discarded exhausted fixer,
will any of the remaining chemical cause an adverse effect on a septic
system?" While another poster made a point of identifying sulphate and
sulfur, I don't know if the mere existence of these compounds is a problem


Isn't sulfur a common part of acid rain? It's an okay additive in
organic gardening.

Nick

Nick Zentena wrote

Isn't sulfur a common part of acid rain? It's an okay additive in
organic gardening.

Gypsum is CaSO4, calcium sulfate. In a septic system, if it
interacts at all, it would form H2SO3 sulfurous acid and highly
insoluable sulfides. What with the complex chemical reactions
takeing place, I'd guess other, exotic sulfur containing
compounds are formed.
Sulfurous and sulfuric acids are the sulfur acids in acid rain.
I think it's the acid part which is ruining the rain. Dan