Comparing Sanitation Delivery Modalities in Urban Informal Settlement Schools: A Randomized Trial in Nairobi, Kenya

Abstract

The provision of safely managed sanitation in informal settlements is a challenge, especially in schools that require durable, clean, sex-segregated facilities for a large number of children. In informal settlements in Nairobi, school sanitation facilities demand considerable capital costs, yet are prone to breakage and often unhygienic. The private sector may be able to provide quality facilities and services to schools at lower costs as an alternative to the sanitation that is traditionally provided by the government. We conducted a randomized trial comparing private sector service delivery (PSSD) of urine-diverting dry latrines with routine waste collection and maintenance and government standard delivery (GSD) of cistern-flush toilets or ventilated improved pit latrines. The primary outcomes were facility maintenance, use, exposure to fecal contamination, and cost. Schools were followed for one school year. There were few differences in maintenance and pathogen exposure between PSSD and GSD toilets. Use of the PSSD toilets was 128% higher than GSD toilets, as measured with electronic motion detectors. The initial cost of private sector service delivery was USD 2053 (KES 210,000) per school, which was lower than the average cost of rehabilitating the government standard flush-type toilets (USD 9306 (KES 922,638)) and constructing new facilities (USD 114,889 (KES 1,169,668)). The private sector delivery of dry sanitation provided a feasible alternative to the delivery of sewage sanitation in Nairobi informal settlements and might elsewhere in sub-Saharan Africa.

21st century research in urban WASH and health in sub-Saharan Africa: methods and outcomes in transition

“…Seven experimental or quasi-experimental studies evaluated the effectiveness of WASH interventions on health outcomes in urban SSA since 2000 (Table 2). Four studies used an individual or cluster randomised controlled trial design to evaluate impact (Du Preez et al 2011;Davis et al 2013;Bohnert et al 2016), one used randomisation to allocate clusters to one of four interventions, without a control comparison group (Davis et al 2011), one applied a non-randomised controlled, quasi-experimental design (Montgomery et al 2012), and one simply applied a pre-and post-intervention survey to assess intervention impact over time (Ryman et al 2012). All interventions under evaluation used information and education strategies to promote particular behaviours.…”

“…The study by is notable for explicitly addressing shared responsibility and community-level action and hygienic behaviours whereas the other studies largely focussed on individual-or household-level behaviours. Five studies supplemented information with technical interventions of varying degrees of sophistication, ranging from basic hygiene kits to solar technology and sanitation services (Bohnert et al 2016;Du Preez et al 2011;Davis et al 2013;Montgomery et al 2012;Ryman et al 2012). No included studies explicitly addressed contextual drivers of WASH such as governmental, institutional, private or public sector factors.…”

“…The health outcomes of focus of most studies included hygiene behaviours including water treatment behaviours (Bohnert et al 2016;Davis et al 2011Davis et al , 2013Ryman et al 2012; Tumwebaze and Mosler 2015), though Bohnert et al (2016) and Davis et al (2013) also assessed exposure to faecal contamination and self-reported diarrhoea morbidity, respectively. The primary outcome in the randomised controlled trial by Du Preez et al (2011) was self-reported diarrhoeal disease incidence, though objective measures of child growth were also included.…”

“…These conclusions and claims of causality may be overstated, however, and the observed positive effects of hand sanitisers must be interpreted with consideration of the unblinded, self-reported limitations of the study design. Bohnert et al (2016) measured a number of variables such as toilet maintenance and cleanliness, activation for handwashing rates among school children and environmental exposure of toilet surfaces and hand contamination, using E. coli as a proxy for fecal contamination. The study compared urine-diversion (dry) toilets delivered by private sector sanitation delivery (PSSD) to Government Standard Delivery (GSD) of ventilated pit latrines or flush toilets in public schools in Nairobi.…”

“…The increase in E. coli contamination is linked to increased usage despite continued cleaning. Despite a lack of robust evidence presenting clear benefits of one modality over another, Bohnert et al (2016) argue that the establishing of the feasibility of providing a lower-cost, private sanitation service similar to that provided by the government is an important finding.…”