Socio-economic analysis of constructed wetlands systems for hygienic sanitation in Tanzania

In Tanzania, as in many other developing countries, the great majority of people still do not have access to safe drinking water supply and hygienic sanitation. For institutions, such as schools and hospitals, where water supply is available, constructed wetlands system (CW) can provide hygienic sanitation. However, successful implementation of constructed wetlands in Tanzania is still hindered by to a lack of investment capital and lack of knowledge and commitment of users, responsible government institutions and international development agencies. Based on an evaluation of 5 constructed wetland projects, including an in depth socio economic analysis of 2 systems and a broader dynamic innovation system analysis of the water and sanitation sector in Tanzania, we provide insight in bottlenecks and opportunities for constructed wetland projects in Tanzania. This analysis shows that failure of constructed wetland projects is often due to the great discrepancy between the limited private and large societal net benefits. Socio-economic costs of diseases are not visible to decision makers and remain therefore unaccounted for. As a result implementation of hygienic sanitation systems fails due to unrealistic attempts at cost-saving by taking short-cuts in the implementation and maintenance. On the other hand, there are also very promising examples such as the constructed wetland system at the Ruaha Secondary School, whose sanitation was found to be technically, financially as well as social-economically successful.