for the amounts of chemicals you would be putting into your spetic system, there is no problem for any of them (except color chemistry) Actually if you put it into a seperate tank with all your rinse wanter and wash water, you would have a very good lawn fertilzer. Bruce Barnbaum told us how he stumbled on this, I have since tried it in my back yard, and it works beuatifully. As for the silver that is in the fix, there is such a minute amount as to not be a problem. If you do worry about it, get a silver recovery system. Some of the household cleaners you use are more harmful than the photo chems. They all go down the drain.