Pit latrines

Pit latrines (Fig.7) are applied widely in underdeveloped population centres and in remote locations, where water supply is limited or does not exist. In such cases wastewater is not generated, therefore pit latrines could be regarded as a sanitation technology for disposal of human waste. They can be a source of diffuse pollution, and more specifically, pollution of ground water as shown in Figure 8. The figure shows the mechanism of ground water pollution. It also stresses on the fact that if a well is located in the vicinity, polluted ground water may be a serious public health risk. Consideration should be given the fact that polluted ground water has very low self-purification capacity and once polluted, will remain in this condition for decades. In order to avoid ground water pollution and to allow for a save application, the minimum distance between the bottom of the pit and the maximum ground water level should be at least 3m. This would allow for biological treatment of selected pollutants in the soil layer. It is clear that this facility cannot be applied safely in areas with high ground water level. Alternative solutions are dry toilets, chemical toilets or construction of simplified sewer systems.

In urban underdeveloped areas, pit latrines need to be emptied periodically, based on the pit volume and the number of persons served. If the pit latrine is located in an area with high ground water level it will cause problems not only related to environmental pollution but to its operation as well, because it will fill with water and needs to be emptied often. In rural areas, where no empting facilities are available, usually a new pit latrine needs to be build.

Pit latrines are not a sustainable solution in areas of high ground water level!