I just got off the subway and the entire station was filled with an noxious odor such that people were gagging as they exited.

When I got to the street, I saw a cooking oil recovery truck parked right next to the fresh air intake for the subway station pumping oil from a restaurant.

Since the truck is filled with mixed fats, oils & grease, (commonly known as FOG waste) which are in various states of decomposition and decay, is there a possibility that Hydrogen Sulfide is being formed?

  • $\begingroup$ Seems like you would need a source of sulfur to react with the hydrocarbons, no? $\endgroup$ – Jon Custer Jan 12 at 15:28
  • $\begingroup$ A lot of solids from food end up in the waste oil, but I have no idea of the sulfur content and if it would be sufficient to react. The tank is under vacuum when they are pumping so it could lower the boiling point of the liquid, but don’t know if it’s enough of a vacuum to cause a reaction if there is anything it can react with. $\endgroup$ – Jack Spencer Jan 12 at 18:49
  • $\begingroup$ BTW, there are buses in the area running on recycled cooking oil, and the exhaust smells like fried potatoes... not at all bad (and probably increasing fast-food sales). $\endgroup$ – DrMoishe Pippik Jan 12 at 21:35
  • $\begingroup$ That's been refined though! Have you ever been near one of the trucks pumping waste oil? I'd choose a septic tank pump truck's vacuum exhaust over a FOG waste truck any day! $\endgroup$ – Jack Spencer Jan 12 at 22:14
  • 3
    $\begingroup$ The main oxidation products of fats and oils are aldehydes and they smell really nasty. $\endgroup$ – M. Farooq Jan 13 at 2:30