Ventilated improved pit latrines : recent developments in Zimbabwe

This paper describes recent developments ventilated improved pit (VIP) latrines designed in Zimbabwe. Two basic designs are presented, one suitable for peri-urban areas and the other for rural areas. The peri-urban VIP latrine consists of a circular pit fully or partially lined with cement mortar and with, at its top, a brick collar which is supported by a thick concrete slab precast on site. A high spiral shaped superstructure is constructed on the cover slab in ferrocement or brick and a flat roof slab placed on top. An asbestos cement or polyvinyl chloride vent pipe with a fly screen at its top is then erected immediately adjacent to the outside of the superstructure. The rural VIP latrine consists of a rectangular pit over which are placed longitudinal and transverse wooden logs of around 100 mm diameter which are then covered with anthill soil and a thin layer of cement mortar. A spiral superstructure is then built in mud and wattle, thatch, soil or local bricks and covered with a conically shaped thatched roof. The vent pipe is made from local reeds, fitted with a fly screen and rendered with cement mortar. Both the peri-urban and rural VIP latrine designs have been found to be socially acceptable in Zimbabwe and very effective in eliminating odours. [author's abstract]