The composting toilets at Rancho Mastatal convert human waste into fertilizer for plants. It has two large compartments to store waste, and it uses sawdust produced either from the onsite workshop, or from another local sawdust resource. The frame of the structure was created using bamboo and timber connected with a mortise and tenon technique.
The various components of the composting toilet are described in the table below.
From left to right this image displays the toilet, the sawdust compartment, and the lid to the second waste container. The toilet sits on top of one compartment that takes up half of the storage space. When it is full the toilet is moved to the compartment on the right. A lid is kept on the toilet box when it is not in use to help keep pests out of the compost. A generous amount of sawdust must be added after each toilet use to provide ample organic matter for the composting process to occur properly.
This image shows the gate to the left waste compartment. When it is full the toilet is moved to the right compartment, and the material in the left compartment is given time to fully compost. As the right compartment fills up, the left one has time to become compost and be used for gardening. When the right compartment fills up the toilet is switched back to the left compartment and the cycle repeats.
The chimney allows harmful gases to escape from the waste compartments.