|The Use of Effluents from Biolatrines in Tanzania (African Development Foundation, 1996, 38 pages)|
The use of excrete in agriculture and aquaculture is becoming increasingly important. The economic benefits of such use must be balanced against the associated public health risks, but these risks have often been exaggerated.
This research shows that recycling excreta through biolatrines and using the effluents as fertilizer is, in fact, safer than existing inadequate or non-existent methods of waste treatment. The risk of pathogen survival after biolatrine treatment is relatively small. Public health as well as agriculture would benefit substantially from adoption of this technology. Given the lack of resources for sewerage-based disposal systems, it is really the only viable alternative.
The most important variable to consider is adequate retention fume, a factor that must be taken into account in design of biolatrines with adequate capacity for the expected usage. When retention time is below 80 days, the effluents must be tested for pathogens before application in crop fields. When retention time is above 120 days, the effluents can safely be applied in crop fields without necessarily carrying out tests. For vegetables with short life spans like spinach and lettuce, however, effluents should only be applied after tests indicate they are free of pathogens. In this case, also, the application should be only once, before the vegetables are planted.
In addition to benefits for public health and agricultural production from properly managed biolatrine schemes, there are also potential benefits for the environment, as compared with sewerage systems. Biolatrine technology avoids the surface water pollution that might occur from discharge of wastes into rivers or lakes. It conserves fresh water resources used for flush toilets, and it conserves the soil on fields to which it is applied. By reducing the potential demand for artificial fertilizers, it conserves foreign exchange and possible pollution from industrial plants.
Human behavioral patterns are a key determinant in the transmission of excreta-related diseases in general, and no less in their transmission through excrete and waste water use. An ongoing campaign of public awareness is necessary to promote adequate understanding, acceptance and appropriate use of biolatrine technology. This campaign must include both the advantages of fertilizer use and the public health advantages.
It seems, nevertheless, that public resistance to biolatrines is less of an obstacle than finding the resources for biolatrine installation as well as public awareness campaigns. In order for biolatrine technology to spread around the nation in Tanzania, start-up and promotion efforts at a much larger scale than in Burundi will be needed. The question then becomes one of political will and available resources. One of the most important audiences to convince of the relevance of the technology is skill the policy makers responsible for such strategic decisions.