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JOSarff
02-19-2013, 09:31 PM
At the risk of beating a dead horse I would like some advice.

I am building a new home that will incorporate a grey/black water waste system.

I have been using a septic tank for over 12 years with no problems, so my question is this: Would you classify the water from a final print washer (after selenium toning, rinse, PermaWash or KHCA and a rinse) as grey or black?

I lean toward grey, GF leans toward black.

Thoughts?


Thanks in advance,

Joe

Worker 11811
02-19-2013, 11:08 PM
I'd say that part of that answer has to do with what you plan to do with the gray water. Are you going to use gray water just for watering plants? Will it be used for flushing toilets only? Will it be recycled in another way?

For irrigation, I see no problems. For flushing, maybe. For recycling, no.

Athiril
02-22-2013, 01:12 AM
How about forward osmosis?

mgb74
02-22-2013, 10:11 AM
Look at the msds for toner and fixer. With the caveat that a lot depends on dilution (the amount of chemicals relative to the amount of other liquid in the system), I'd be leery of putting this in my septic tank and I wouldn't use it for any edible plant irrigation. Perhaps I'm being overcautious.

I realize you've been using a septic tank for 12 years, but I would note that a septic system can fail biologically and you wouldn't know it unless your soil was tested. If there's 2 of you in the home and you're in the darkroom every evening, I would be concerned. If it's 4 and you're in there once a week, then maybe not.

fotch
02-22-2013, 11:11 AM
....I realize you've been using a septic tank for 12 years, but I would note that a septic system can fail biologically and you wouldn't know it unless your soil was tested.... .

When septic systems fail, the start clogging the septic field and the fluid starts backing up, and you will know it. At least, that is my understanding.

mgb74
02-22-2013, 12:06 PM
When septic systems fail, the start clogging the septic field and the fluid starts backing up, and you will know it. At least, that is my understanding.

That is a typical scenario when solids don't settle out in the tank. But most of the biologic action to "clean" the effluent actually takes place outside (past) the tank, in the drainfield. If chemicals you introduce interfere with that, you could contaminate the groundwater.

If that were to happen, there might also be an impact in the tank itself (causing a backup as you note). But that might not happen for some time (as sludge builds up) and, depending on frequency of pumping out the tank, possibly never known. Meanwhile, you may not be effectively treating the effluent.

I haven't been able to find definitive info on photo chemicals and septic tanks. Lots of discussion and anecdotal experience on APUG (and elsewhere), but little hard data. Kodak "does not recommend the use of septic systems for disposal of photographic processing", but years ago they said it was OK. Who knows whether it's driven by science, more concern about groundwater, or the lawyers?

A lot of variables. If the OP is sending all his other "common" contaminants (bleach from washing machine and dishwasher, antibacterial soap) out as grey water, the impact of the photo chemicals may be less significant. But if his septic tank is small (reflecting the separate grey water system) there is less dilution.

JOSarff
02-23-2013, 05:59 PM
A lot of variables. If the OP is sending all his other "common" contaminants (bleach from washing machine and dishwasher, antibacterial soap) out as grey water, the impact of the photo chemicals may be less significant. But if his septic tank is small (reflecting the separate grey water system) there is less dilution.

The system is maintained properly and is biologicially active. The major problem in most home darkrooms/septic systems (and it has been discussed elsewhere) is the volume of wash water damaging the biological activity of the tank, not the chemicals. Putting 5 to 600 gallons of waste water from a household a month is not a problem, 200 gallons a day of wash water from the print washer is.

Pioneer
02-23-2013, 06:11 PM
The system is maintained properly and is biologicially active. The major problem in most home darkrooms/septic systems (and it has been discussed elsewhere) is the volume of wash water damaging the biological activity of the tank, not the chemicals. Putting 5 to 600 gallons of waste water from a household a month is not a problem, 200 gallons a day of wash water from the print washer is.

That is the big reason I do not cycle my processing water through my septic. I am less concerned with the chemical issues and more concerned with the waste water dilution issues. I have actually seen this happen with a large family that used their dishwasher and clothes washer a lot. For now I use my process water for irrigation.