Percocet used for pain relief is a narcotic medication and prescriptions can prevent people from getting high on Percocet without medical reason.In fact, the Percocet high feeling can get you into lots of problems.
I think the formula of the perfume itself decides how fast it will spoil. My perfumes from Britney Spears Curious and Salvatore Ferragamo went bad within a year and a half. The Britney Spears one developed some precipitation and started smelling like alcohol, while the Salvatore Ferragamo just smelled plain weird.
Bacteria isn't a bad thing, it's a good thing, especially concerning sewage. As bad as it smells, the odor of sewage is the bacteria digesting the waste and turning it into harmless by-products, and water. You should have left the sewage alone, instead of killing the microbes that were working for you.