The thatched cob, waterless composting toilet at Felin Uchaf, Wales

This is the composting toilet at Felin Uchaf in Wales. The building is cob, that's clay with sand and straw, on a slate stem wall with reeds collected from the nearby estuary for the thatched roof. The functional part of the building is a Natsol waterless composting toilet. You can watch a video (right) about the building and its composting toilet in a program clip from the BBC.

Correctly designed and operated a composting toilet shouldn't smell at all. Urine is the biggest challenge for compost toilets due to the ammonia and the sheer volume of liquid that must be evaporated or drained. Draining the vault from the base typically requires the chamber to be out of the ground, making level access difficult, unless a pump is used. By diverting urine to a shallow soak-away it is prevented from entering the compost pile.