20.4.1 Arborloo – a single pit method
A simple form of ecological sanitation is the Arborloo (Figure 20.5). This consists of a single, unlined shallow pit with a portable ring beam (circular support), slab and superstructure. It is used like a normal latrine but with the regular addition of soil, wood ash and leaves. When it is full, it is covered with leaves and soil and a small tree is planted on top to grow in the compost. (The tree gives the system its name; ‘arbor’ is Latin for ‘tree’.) Another pit is dug nearby and the whole structure is relocated over the new pit. No handling of the waste is required. If a fruit tree or other useful variety is grown there is the added benefit of food or income.