The Roman were advanced but their toilet plumbing left a little to be desired. The toilet was often located near the kitchen so getting rid of kitchen waste and bodily waste easier with less plumbing. Sewer gas wasn’t a factor considered so there were explosions in the kitchen relating to the ignition of sewer gas.
They didn’t know about gases and such at that time. It wasn’t until the 16-1700’s that gases were studied and their laws were institutionalized..............
http://thescienceclassroom.org/chemistry-lessons/gases/the-gas-laws/
The Roman were advanced but their toilet plumbing left a little to be desired.