"Nick Maclaren" wrote in message
...

However, it will compost perfectly well in the bags if holes are
punched in them, and to some extent even if not. I agree with
you that it is likely to smell less if done in the open.

Anaerobic digestion of the sewage is going to be messy, though, it'll get
moist and rancid smelling fast. Anaerobic digestion of faecal waste is an
area of microbiology inhabited mostly by massochists. Punchng lots of holes
in the bag sounds like a reasonable option, though.