A dry toilet installation comprising: - a toilet seat in the form of a hollow body which, opposite a lower bearing surface on the ground, has an upper surface in which there is arranged a gravity evacuation opening for liquid effluent and solid waste; - a conveyor belt mounted at an angle delimiting, between a bottom part and a top part, a receiving surface for liquid effluent and solid waste, to ensure the separating under gravity of liquid effluent and solid waste, a part of the conveyor belt, starting from its bottom part, mounted inside the toilet seat while the conveyor belt project from the rear face of the seat through a passageway made in said rear face of the seat; - a device for collecting the liquid effluent derived from the conveyor belt) comprising a receiving tank; - a transfer system ensuring the forward travel of the conveyor belt and hence the conveying of the solid waste from a receiving area located directly below the evacuation opening towards a storage area, characterized in that: - the conveyor belt is mounted inside the toilet seat so that directly underneath the evacuation opening the distance between the conveyor belt and said opening is between 15 and 35 cm; - the gravity evacuation opening is skirted by a down pipe extending as far as the receiving surface, being positioned so that its free end ( 23 1) is not parallel to the receiving surface, the anterior part of the free end ( 23 1) of the down pipe being mounted to lie flush with the receiving surface so as to act as stop abutment for solid waste, the posterior part of the free end ( 23 1) of the down pipe lying away from the receiving surface to allow the passing of solid waste, the anterior and posterior parts of the free end ( 23 1) taking into account the front and rear faces of the seat. - the receiving tank of the collection device collecting liquid effluent is mounted inside the toilet seat directly underneath the bottom part of the conveyor belt. - a toilet seat in the form of a hollow body which, opposite a lower bearing surface on the ground, has an upper surface in which there is arranged a gravity evacuation opening for liquid effluent and solid waste; - a conveyor belt mounted at an angle delimiting, between a bottom part and a top part, a receiving surface for liquid effluent and solid waste, to ensure the separating under gravity of liquid effluent and solid waste, a part of the conveyor belt, starting from its bottom part, mounted inside the toilet seat while the conveyor belt project from the rear face of the seat through a passageway made in said rear face of the seat; - a device for collecting the liquid effluent derived from the conveyor belt) comprising a receiving tank; - a transfer system ensuring the forward travel of the conveyor belt and hence the conveying of the solid waste from a receiving area located directly below the evacuation opening towards a storage area, characterized in that: - the conveyor belt is mounted inside the toilet seat so that directly underneath the evacuation opening the distance between the conveyor belt and said opening is between 15 and 35 cm; - the gravity evacuation opening is skirted by a down pipe extending as far as the receiving surface, being positioned so that its free end ( 23 1) is not parallel to the receiving surface, the anterior part of the free end ( 23 1) of the down pipe being mounted to lie flush with the receiving surface so as to act as stop abutment for solid waste, the posterior part of the free end ( 23 1) of the down pipe lying away from the receiving surface to allow the passing of solid waste, the anterior and posterior parts of the free end ( 23 1) taking into account the front and rear faces of the seat. - the receiving tank of the collection device collecting liquid effluent is mounted inside the toilet seat directly underneath the bottom part of the conveyor belt.