Assessment of urban solid waste logistics systems: the case of Kampala, Uganda

Many cities, especially in developing countries, are facing challenges in the management of solid waste. The aim of the study was to develop effective logistics systems for solid waste management in urban areas of developing countries, with a specific focus on Kampala, Uganda. This thesis contains an assessment of the reverse logistics systems that enable effective recapturing of valuable products from urban solid waste. The study mapped the waste collection systems in Kampala using a geographic information system (GIS), i.e. ArcGIS software, and examined the existing models of waste collection to the final disposal destinations. It was found that food and yard wastes constitute 92.7 % of the waste that reaches landfills in Kampala. Recyclables and other special wastes constitute only 7.3 % of the total waste. The generation rate of solid wastes on average from poor areas, upscale wealthier areas, business centres and market areas was 582, 169, 105 and 90 tonnes/day respectively. The study optimised travel distances, number of vehicles and collection time, while maximising total waste collection for environmental sustainability. Results showed that, an increase from a 6-tonne truck to a 10-tonne one reduced the travel distance by 39 %, while an increase from a 10-tonne truck to an 18-tonne truck reduced the travel distance by 34 % considering the current 40 % waste collection. Suggestions regarding the best waste collection routes and a suitable vehicle fleet and capacity to be used by Kampala Capital City Authority (KCCA) have been provided in this study. The research study further developed an overview of reverse logistics at the Kiteezi landfill. The study analysed in detail the collection, re-processing, re-distribution and final markets of these products into a reversed supply chain network of products delivered to the landfill. Of the products at the Kiteezi landfill, 14 % was channelled into the reverse chain, 63 % could be included in the distribution chain but were left out and disposed of while the remaining 23 % was buried straightaway. The main conclusion of the work was that solid waste management in Kampala is characterised by inefficient collection methods, insufficient coverage of the collection system and improper disposal of municipal solid waste. The existing system pertaining to reverse logistics suffers from unfavourable economics and legislative, technical and operational constraints that affect the recycling rate in Kampala compared to developed countries. This study presented large-scale data that can be used to improve solid waste management in other cities in developing countries

Quantities and qualities of fecal sludge : experiences from field implementation with a Volaser in 7 countries during a pandemic

Reasonable estimates for quantities and qualities (Q&Q) of fecal sludge that accumulate in onsite sanitation containments are fundamental for the design of appropriate management and treatment solutions, from community to city-scale. There are increasing attempts to improve Q&Q estimates, but current approaches are still at a conceptual level, and are not yet standardized with confirmed statistical relationships. To reach this level, we will need consistent approaches for planning, measuring, and global collaborations. Hence, the objectives of this study were: (1) to assess and compare Q&Q of fecal sludge from seven cities and communities, and explore statistical relationships that could be used to increase accuracy of Q&Q estimations; (2) to test and launch the Volaser device for measuring in situ volumes of fecal sludge; and (3) to capture lessons learned from field implementation with collaborators in seven countries during a global pandemic when no international travel was possible. The study took place in Ghana, India, Lebanon, Kenya, Sierra Leone, Uganda, and Zambia during the COVID-19 pandemic. Q&Qs were measured in 204 containments with a Volaser, laboratory analysis, and questionnaire. Results indicate that there are differences in Total Solids (TS) and Chemical Oxygen Demand (COD) in fecal sludge based on containment type, toilet type, source, and whether there is a water connection on the premises. Based on the results of this study, together with previously published open-source data, an empirical relationship for Volatile Solids (VS) and TS of 0.49 (R2 = 0.88) was established using 1,206 data points. For COD/TS, no significant relationship was observed. Developing such empirical relationships will be useful for planning and modeling approaches. An external evaluation was conducted to evaluate overall project management, Volaser technology transfer, and effects of collaborating during the COVID-19 pandemic. Success factors for collaborating with new and existing partners without face-to-face meetings included laboratory capacity and experience with analytical methods, study objectives that were relevant for the partner and locality, and a strong quality assurance plan to ensure comparability of results. The lessons learned can be taken forward as ways to reduce carbon footprint, and contribute to resilient, inclusive development research projects