...Sorry
Okay, so, i have several.
Dectorio for one, but thats probably not it, then there's tiles absorb pollution, which could be it, and combat mechanics overhaul, which i have no clue what it does to landfill, and alien biomes, and cargo ships, two that are unlikely to be the reason why.
Edit: Also, yes, i do have it on and i did place them after enabling the mod