Thie question of dark room and chemicals has been discussed in length on another thread. Under thee reducing conditions of a septic tank silver ions are converted to silver sulfide which is VERY insoluble so no silver gets into the evironment.
Where it would presumably eventually settle out into the sludge at the bottom of the tank that is pumped out every 5-7 years for proper disposal? At least this is what I've read elsewhere.
"Hate is an adolescent term used to stop discussion with people you disagree with. You can do better than that."
—'blanksy', December 13, 2013