My home has a septic system with a vented lid to let the sewer gasses escape from the tank itself. As a result, it seems like far less gas (if any) would travel up the waste plumbing and exit through the vents downstream of the P-traps. So I've been wondering: given the vented septic tank, is there any actual technical reason why my home plumbing needs to have traps and vents?
CYA provision: I'm not asking this because I'm planning to remove all the traps and vents or anything wacky and illegal and pointless like that. There would be no benefit at all to anyone, and it might even hurt future owners if the house is ever put on the city sewer or something. I'm just curious and I want to understand the systems a little bit better. Because it sure seems like traps and vents are designed to solve a problem that my septic tank solves on its own.