The last time I did much home brewing I was on a municipal sewer system. A little bleach or sulphite (spent hops & grain, whatever) down the toilet couldn't affect it. Now that I live in the country, I worry about knocking my septic tank out of commission.
Is there a sanitizer that will do the job without snuffing the bacteria in the tank? Or is that a big worry?
Use any sanitizer you like...in the amounts you use it won't hurt the septic system. Thfink about the hundreds of gallons of your septic tank vs. an oz. or so of sanitizer. I've brewed 455 batches, and I've sent the sanitizer from every one into my septic system with no ill effects.
A little Starsan or bleach in the septic tank won't do any damage, provided it's in limited amounts (ie, don't pour a whole jug of bleach down the toilet...)
I do avoid putting the spent hops and grain down the toilet however. Excess solid material going into a septic system will eventually build up, either in the tank (needs to be pumped) or in your septic field, depending on design. I usually just dump it in my compost pile.
