The pig toilet was once a key sanitation building in rural China, Korea, and India. It was ruthlessly efficient, combining a toilet for people with a sty for pigs.
Pigs are omnivorous; they will apparently eat anything. (And if you’ve seen the films Hannibal or Snatch, you’ll know how far a determined script-writer will take that fact.) Sty designs going back at least two thousand years have taken advantage of this fact to produce a highly efficient double-use building: the pig toilet.
The model pictured above is an ancient Chinese funerary model. Like the dioramas of ancient Egypt, it portrayed in miniature a common part of Han dynasty life. I hope it does not need much explanation, but essentially the upper layer is a privy, a dry toilet for people. The lower layer is a pig sty; the pigs disposed of the deposits, provided fertilizer for the farm, and eventually became food for the farmers.
It’s an impressive piece of recycling, but not without its flaws. Taenia solium, the pork tapeworm, can go from human faeces into pigs and back into humans if the pork is not cooked well enough. The design of this particular toilet made that whole cycle unfortunately easy. Pig toilets are mostly a thing of the past now, although apparently some still survive in rural parts of China and India.