Is it OK to put this stuff in my 167bbl. underground fermenter (septic tank)?
survey seems to say yes.
I’ve been putting PBW (as well as Oxiclean and StarSan) in my septic tank for years with no problems.
John Herskovits of Five Star was on Brew Strong (thebrewingnetwork) a few years ago and specifically stated the PBW and Star Stan were designed to be environmentally safe.