One of the assignments I had when I first started at DuPont was to work on “odor reduction” initiatives at municipal sewage treatment plants. We had to be in every step of the process and learn about it so we could develop new processes to reduce the odors the plants emitted.
The “collection” pumping room is the worst. It’s a confined area where all the raw sewage is pumped for distribution to the treatment tanks. We used to call it “the asshole of the community”.
You literally had to throw your clothes away after spending just 5 minutes in that area. They could never be cleaned enough to eliminate the smell.