Evaluating and modelling a decentralised community-based waste collection system in developing S?o Tom? city

A small-scale waste collection service by means of a motor tricycle was put in place by the com-munity of Boa Morte (in Sao Tome e Principe), as a solution to face the lack of an adequate waste management in their neighbourhood. A qualitative and quantitative evaluation of the service was performed by the authors, including a characterisation of the generated waste, interviews with the population involved, a technical assessment and the development of a cost model. With re-spect to technical aspects, the vehicle chosen has been found to be a satisfactory choice, whereas the productivity of collection is still too low due to the dispersion of collection points. Concerning financial aspects, the cost model reveals that the scale of the scheme is still too small to be com-pletely sustained by its own revenues, but this objective of self-sustainability is achievable within the limits defined for the system, by adding a determined number of new customers without ex-ceeding the fixed maximum working time and introducing some improvements and time optimi-sation.