An evaluation of different provision strategies for scaled-up container-based sanitation

Abstract

Container-based sanitation (CBS) is increasingly used to provide safely managed sanitation in low-income urban settlements. However, questions remain around the viability of scaling up the technology, partly because it relies on regular emptying and servicing of containers by a CBS provider. This paper investigates mechanisms by which this process can be achieved efficiently. Three separate collection strategies are evaluated for their routing efficiencies as CBS goes to scale. An open-source route optimisation solver determines the constituent driving and walking distances necessary for each strategy and has been applied in areas of Cape Town, Cap-Haïtien, Lima and Nairobi. The results indicate that with fewer users (e.g. 50) transfer station models offer the shortest driving routes. However, these do require users to carry their containers (e.g. up to 170 m when stations are 100 m apart). As the number of users increases (e.g. to 5,000), visiting individual houses from a neighbourhood depot offers increasingly efficient driving distances. Overall, however, the results suggest that economies in collection distances for scaled CBS will be largely conditional on greater vehicle capacity (rather than any particular provision strategy). This highlights the importance of road access throughout low-income urban settlements in providing a viable CBS service at scale.

A qualitative study on resource barriers facing scaled container-based sanitation service chains

“…Firstly, the upscaling of CBS operations is intrinsically linked to the nature of the provider, obfuscating any universal 'viable scale' (as this means different things to different entities and stakeholders). The issues around the efficiencies of scaling up on transport strategies are discussed in detail in Ferguson et al (2021). The growing social enterprises detailed in this study use business models relying predominantly on either (i) subscription-based approaches and/or (ii) 'impact investors' (who can accept low financial return for high social impact).…”

Container-Based Sanitation Services and Attrition: An Examination of Drivers and Implications

“…While CBS has identifiable advantages over traditional sanitation systems, it also has unique vulnerabilities. CBS service delivery can be interrupted by disruptions in transportation infrastructure, worker strikes, or pandemics (Saul and Gebauer, 2018;Mackinnon et al, 2019;Russel et al, 2019;World Bank, 2019;Ferguson et al, 2021). CBS technologies also require greater user engagement than more traditional sanitation technologies.…”