RPC
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- Sep 7, 2006
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In pouring darkroom chemicals down the drain, into a septic system, there has been concern that bacterial action could be affected. Bacterial action results in waste materials being broken down. If the waste material builds up in a tank faster than it is broken down, it eventually has to be pumped, which happens routinely with many tanks, more often in larger households.
So as I see it, the worst that could happen if chemicals slow down the rate of bacterial action is that the waste materials would build up a little faster, and simply result in the tank requiring pumping a little earlier. Once pumped, you start fresh. One can choose whether he wants to do this or not, but no real harm is done, no damage. I think it is very unlikely, however, that a typical home darkroom user would even pour enough down the drain to cause this to happen. As I see it, this is really a non-issue.
There is also concern that the ground water could be affected. The broken down waste material, called effluent, is highly toxic, but way septic systems work, the soil filters it, so by the time it gets to the ground water it is fit enough to drink. Anything poured down the drain is also filtered. If this were not the case, there would be polluted ground water everywhere. Another non-issue.
That said, I see no problem with silver-recovery for economic reasons or to preserve the quantity of silver in the world.
So as I see it, the worst that could happen if chemicals slow down the rate of bacterial action is that the waste materials would build up a little faster, and simply result in the tank requiring pumping a little earlier. Once pumped, you start fresh. One can choose whether he wants to do this or not, but no real harm is done, no damage. I think it is very unlikely, however, that a typical home darkroom user would even pour enough down the drain to cause this to happen. As I see it, this is really a non-issue.
There is also concern that the ground water could be affected. The broken down waste material, called effluent, is highly toxic, but way septic systems work, the soil filters it, so by the time it gets to the ground water it is fit enough to drink. Anything poured down the drain is also filtered. If this were not the case, there would be polluted ground water everywhere. Another non-issue.
That said, I see no problem with silver-recovery for economic reasons or to preserve the quantity of silver in the world.


