Double vault toilet

The double vault toilet is the most common type of composting toilet worldwide. After one chamber, or "vault" is filled, it is closed off and the toilet is moved over to fill the second vault. Contents of the first chamber compost while the other chamber is being filled. This prevents any human contact during the composting process. A vent releases any odors above the bathroom, and the area is fly proof. Urine collection is not visible in this diagram. (drawing by Annie Danger)