Abstract: A lavatory bench, or toilet, in which solid wastes are collected and biologically decomposed. The bench comprises a container beneath the seat and near the top of the container is a rotary member to which material is supplied and which, while rotating, distributes the material within the container. The container is advantageously heated. A casing is provided which supports the seat and which surrounds the container and from which there leads a lead stack, or outlet pipe. The rotation of the aforesaid member causes air circulation within the device and promotes the movement of air out through the outlet pipe. The rotatable member near the top of the container also serves the function of shutting off the inside of the container from view.