Linking solid waste and onsite sanitation: Quantification, stakeholder perspectives, and practices in two divisions of Kampala, Uganda

• Most of the solid waste collected from onsite sanitation systems was taboo waste. • Management of taboo waste needs to be considered rather than general solid waste. • New classification systems are needed to understand the fate of solid waste. • Stakeholders did not consider the relationship between sanitation and solid waste. • For sustainable and appropriate solutions an integrated approach is required. Understanding the connection between solid waste and sanitation is crucial for improving both systems. This exploratory case study is the first to examine the type and amount of solid waste in onsite sanitation systems, the reasons behind these practices, their impact, and potential prevention methods, across various stakeholders. The study was conducted in two municipal divisions of Kampala, Uganda (Kawempe and Makindye). Solid waste from 19 shared sanitation systems was collected, dried, classified, and quantified during emptying. Interviews were conducted with 20 emptiers, 40 users (20 male, 20 female), and 16 key informants (all male). Most solid waste found in pit latrines and septic tanks was classified as “taboo” waste—items hidden due to social, cultural, or religious reasons. The reasons given for disposing of solid waste in these systems supports previous hypotheses which had remained unexplored. This study generated new hypotheses, particularly emphasizing the role of “taboo” waste, due to its comprehensive methodology. Findings highlight the need for sanitation and waste management sectors to address “taboo” waste specifically rather than general solid waste. Additionally, no stakeholders had considered the complex relationship between these systems, yet an integrated approach is essential for sustainable solutions. These novel insights are critical for solid waste and sanitation specialists worldwide, emphasizing the importance of addressing hidden waste disposal behaviours to improve system efficiency and sustainability.