The arborloo works by temporarily putting the slab and superstructure above a shallow pit while it fills.
Feces, urine, paper, leaves, other materials for wiping, and potentially anal wash water all go into the pit.
[2] Feces are safely stored and converted in the soil, avoiding disease transmission, and do not have to be processed or manipulated by anyone.
By using the nutrient-rich soil of a retired pit, the arborloo, in effect, treats feces as a resource rather than a waste product.
The advantages of not making a roof include: more light, better ventilation, automatic rinsing with the rain, disinfection via solar ultraviolet radiation, reduced cost, and less weight.