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Aims: To determine the magnitude of microbial risks from waterborne viruses and bacteria in Bwaise III in Kampala (Uganda), a typical slum in Sub-Saharan Africa. Methods and Results: A quantitative microbial risk assessment (QMRA) was carried out to determine the magnitude of microbial risks from waterborne pathogens through various exposure pathways in Bwaise III in Kampala (Uganda). This was based on the concentration of Escherichia coli O157:H7, Salmonella spp., rotavirus (RV) and human adenoviruses F and G (HAdV) in spring water, tap water, surface water, grey water and contaminated soil samples. The total disease burden was 680 disability-adjusted life years (DALYs) per 1000 persons per year. The highest disease burden contribution was caused by exposure to surface water open drainage channels (39%) followed by exposure to grey water in tertiary drains (24%), storage containers (22%), unprotected springs (8%), contaminated soil (7%) and tap water (0Á02%). The highest percentage of the mean estimated infections was caused by E. coli O157:H7 (41%) followed by HAdV (32%), RV (20%) and Salmonella spp. (7%). In addition, the highest infection risk was 1 caused by HAdV in surface water at the slum outlet, while the lowest infection risk was 2Á71 9 10 À6 caused by E. coli O157:H7 in tap water. Conclusions:The results show that the slum environment is polluted, and the disease burden from each of the exposure routes in Bwaise III slum, with the exception of tap water, was much higher than the WHO reference level of tolerable risk of 1 9 10 À6 DALYs per person per year.

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Faecal sludge (FS), a product from on-site sanitation systems, poses a management challenge in densely populated urban slums of Sub-Saharan Africa (SSA). Currently, FS or its liquid fraction after dewatering is co-treated with sewage in conventional treatment plants. When de-watered, the solids stream is dried and stored further as the terminal treatment or is co-treated directly with organic solid wastes in composting or anaerobic digestion systems. To implement these, FS has to be collected and transported. Also, land is needed, but it is in most cases limited in slums or their vicinity. The collection and transport of FS from slums is costly due to lack of access, traffic congestion and long travel distances to treatment plants. Moreover, uncollected FS poses health risks and pollutes surface and/or ground water within slums. This review demonstrates that currently utilized technologies and practices fall short in various ways and discusses the possibility of minimizing FS management related costs, risks and pollution in urban slums by decentralized treatment and end-use. It also discusses the possible FS-derived end-products and their benefits to urban slum dwellers. Substitution of a part of natural materials (sand and clay) when building and/or biomass (firewood and charcoal) for cooking with FS derived end-products could multiply the benefits of improved sanitation to slum dwellers.