AKA what do underground civs do with their poop?
Vast underground networks of caverns, tunnels and caves are a staple adventurers' playground in many classic tabletop RPGs.
To make for entertaining games, these are populated with random monsters, eldrich beings and whole cities of creatures like dwarves, mindflayers, drow and other, more exotic, creatures. The cities and towns of the underground are often surprisingly populous and numerous (again to make for a better story I suspect).
That's a lot of potential poop to deal with right there.
Modern engineers might struggle in this environment, but D&D and other tabletop RPGs often assume that cities are pre-industrial. It goes without saying that without adequate sanitation: disease will spread, precious cave real estate will clog up, and dangerous predators and scavengers will be attracted to the stink.
Question: What is the most effective way for a pre-industrial city of approx 10 000 underground dwellers to manage their waste?
Assume the additional environmental conditions:
- Access to the surface world is often difficult or dangerous.
- Light sources are often weak: luminescent fungi, eldrich glow, almost certainly no sunlight.
- Travel through the dark and winding paths is also dangerous.
- Magic is insufficient for the clean-up task.
- Water is limited to underground rivers and lakes (replenished by rain from the sunlit world).
- Dumping waste in water is possible, but if it doesn't wash into your own water supply it will almost certainly head into your neighbors' - which leads to strained relations.
- Additionally, there is no rain underground, so waste stays where it's left or spread.