Full online library
Scientific support for the design and operation of ventilated improved pit latrines (VIPs)
A comprehensive review of literature relating to the design and operation of pit latrines, processes in pit latrines and pit latrine additives was undertaken.
There is not much formal scientific literature in terms of journal publications or conference proceedings that provide much insight into the processes in pit latrines.
However there is a wide range of literature relating to design, operation and maintenance issues that shed some light on the nature of pit latrine contents and the processes that may occur there.
It was concluded that the dominant mechanism of stabilisation in the unaerated bulk of the pit latrine contents would be anaerobic digestion, while some aerobic degradation would occur at the top layers. In most pits which are not sealed, movement of moisture in and out of the pits depends on the type of soil/rock in which the pit is located, the presence and height of groundwater and the amount of moisture added to the pit. Soluble and to a lesser extent colloidal material move in and out of the pit with the moisture flow.
The movement of soluble organic material out of the pit with moisture flow may be a significant mechanism of removal of organic content from the pit. The literature review also highlighted the fact that there is usually a lot of non-degradable material in pits, and that the amount and type of material in the pit depended on user habits and was linked to the solid refuse removal services available to the pit users.
School of Chemical Engineering, University of KwaZulu-Natal, South Africa
Foxon, K. (2008). Scientific support for the design and operation of ventilated improved pit latrines (VIPs). School of Chemical Engineering, University of KwaZulu-Natal, South Africa.