2025/01/01 by H Tomoi · 1 voice
Economics, Econometrics and Finance · Environmental Science · Nursing · #Child Nutrition and Water Access #Economic and Environmental Valuation #Municipal Solid Waste Management
paper · doi:10.17037/pubs.04678323
openalex publication_date 2025/01/01 · openalex created_date 2026/02/03 · openalex updated_date 2026/07/01
Effective faecal sludge management (FSM) is a key public health and environmental concern. Safe emptying and transport services for waste that accumulates in onsite sanitation - such as pit latrines - are essential to keep those facilities usable. Due to their design, 40% of onsite facilities in Sub-Saharan Africa cannot be emptied by mechanised methods (e.g. vacuum trucks) and therefore require manual emptying, which is often not safely operated nor affordable. A novel service approach called group-based emptying, a method to reduce transportation costs and journey times by grouping visits to multiple toilets, is implemented in some countries by vacuum truck operators. However, this approach has not been applied to manual emptying. The aim of this thesis is to assess whether a group-based approach to manual emptying services in an informal settlement in Nairobi, Kenya might offer advantages over existing services. First, I undertook a scoping review on willingness to pay (WTP) for emptying services and identified 20 determinants of WTP. The review revealed few studies have investigated WTP for novel approaches aiming to make services more affordable or convenient, including group-based emptying, posing a significant knowledge gap. Second, I completed a qualitative study to identify barriers and enablers for group-based manual emptying services in the informal settlement of Korogocho in Nairobi, Kenya. The qualitative study identified several important barriers, including vehicle capacity to transport sludge and a norm that toilets are not emptied until they are full. Third, based on the findings from the qualitative study, I undertook a household survey in Korogocho to assess demand for, and the costs of, safe manual emptying. In the survey, the influence of setting an upper limit of emptying volume (~ three drums) on WTP for the service was examined as a strategy to enable emptying at multiple toilets even with small vehicles. On the demand side, WTP for the service with the upper limit was 1.4 USD/drum (mean), which was lower by 0.2 USD/drum than the one without the limit. On the supply side, at least 0.9 USD/drum cost reduction was achieved by the group-based approach compared to the case of visiting one, which outweighed the WTP decrease. My findings suggest that a group-based approach might be a viable cost-reduction strategy for manual emptying, and providing incentives (e.g. a discount price) for small-amount emptying can facilitate the grouping. That said, overall costs (at least 2.5 USD/drum) were not fully covered by the WTP. Overall, the group-based approach is applicable to manual emptying services in Korogocho If some barriers are overcome and the profitability is improved. Public sector engagement Is essential to address some of the barriers and help improve service profitability – for instance, by supporting vehicle acquisition - given that both service providers and users live in poverty