Back when I was an acoustician I used to do a lot of design work for wastewater treatment. Why? 'cuz wastewater treatment facilities often smell like shit, which pisses off their neighbors. Except you can't legislate against stink because stink is not something that can be empirically measured. So the neighbors get back against wastewater treatment facilities for being noisy, which is something you can measure with a $2 app for your phone. So a lot of money gets spent on acoustics for wastewater treatment.

Anyway. Wastewater treatment is full of delightful bullshit urbanism. Used to call it sludge, right? Can't call it sludge anymore. Actually went to meetings where we had a swear jar for anyone who said "sludge." It's "biosolids." So you don't have sludge tanks, you have biosolids tanks. And it isn't "effluent" it's "deflocculated runoff" or some shit.

Do not miss that industry. Altho - I probably wouldn't be sick right now. Healthiest guys I've ever met are the ones that work in wastewater treatment.