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Rapid urbanization and industrialization, uncontrolled population growth, indiscriminate waste discharge and poor infrastructure are problems that African cities are facing. This paper describes an exemplary case study from Jimma, south-west Ethiopia. A cross-sectional study was conducted along the Awetu- Kito drainage system in Jimma town to assess the level of pollution from urban dwellers and related activities. The study indicates that the Environmental Protection Agency ( EPA) norms for biochemical oxygen demand ( BOD), dissolved oxygen ( DO) and orthophosphates are not met downstream of the major industrial and institutional activities. Small-scale industries, Jimma University and residential areas contributed 50, 15 and 23% pollution load on the river, respectively. It can be concluded that the pollution effect in Jimma town is mainly as a result of the growing (uncontrolled) industrial activities and not to discharge of household wastewater. Given the same trends of urbanization and population growth, similar development (socio-economic) indicators and similar climatic conditions, the key findings for Jimma are transferable to other mid-sized African cities. [ABSTRACT FROM AUTHOR]

In this paper the problem of reliable and accurate parameter estimation for unstructured models is considered. It is illustrated how a theoretically optimal design can be successfully translated into a practically feasible, robust, and informative experiment. The well-known parameter estimation problem of Monod kinetic parameters is used as a vehicle to illustrate our approach. As known for a long time, noisy batch measurements do not allow for unique and accurate estimation of the kinetic parameters of the Monod model. Techniques of optimal experiment design are, therefore, exploited to design informative experiments and to improve the parameter estimation accuracy. During the design process, practical feasibility has to be kept in mind. The designed experiments are easy to implement in practice and do not require additional monitoring equipment. Both design and experimental validation of informative fed batch experiments are illustrated with a case study, namely, the growth of the nitrogen-fixing bacteria Azospirillum brasilense.