The design of ventilated improved pit latrines

Excreta-related diseases are responsible for a large proportion of the morbidity and mortality in developing countries, especially amongst low-income communities in urban fringe and rural areas, where adequate water supplies and sanitation facilities are typically absent. Recent research has clearly shown that such diseases can be greatly reduced by: (a) the provision of sanitary toilets, which people of all ages will use and keep clean; (b) the effective treatment of excreta or sewage prior to discharge or reuse; (c) the provision of an adequate water supply for the control of those excreta-related infections which have a water-washed mode of transmission; and (d) an effective and sustained personal hygiene education program. In many cases the least cost sanitation technology will be the ventilated improved pit (VIP) latrine. There are two basic types of VIP latrine, the single pit and one with two pits or alternating VIP latrine. The latter is designed for the removal of the pit contents at regular intervals of two or three years; it is a permanent sanitation facility which is especially suitable for use in medium density urban areas. The purpose of this paper is to discuss general design criteria for VIP latrines and to review recent developments in VIP latrine design.