Health Risks for Sanitation Service Workers along a Container-Based Urine Collection System and Resource Recovery Value Chain

Abstract

Container-based sanitation (CBS) within a comprehensive service system value chain offers a low-cost sanitation option with potential for revenue generation but may increase microbial health risks to sanitation service workers. This study assessed occupational exposure to rotavirus and Shigella spp. during CBS urine collection and subsequent struvite fertilizer production in eThekwini, South Africa. Primary data included high resolution sequences of hand-object contacts from annotated video and measurement of fecal contamination from urine and surfaces likely to be contacted. A stochastic model incorporated chronological surface contacts, pathogen concentrations in urine, and literature data on transfer efficiencies of pathogens to model pathogen concentrations on hands and risk of infection from hand-to-mouth contacts. The probability of infection was highest from exposure to rotavirus during urine collection (∼10–1) and struvite production (∼10–2), though risks from Shigella spp. during urine collection (∼10–3) and struvite production (∼10–4) were non-negligible. Notably, risk of infection was higher during urine collection than during struvite production due to contact with contaminated urine transport containers. In the scale-up of CBS, disinfection of urine transport containers is expected to reduce pathogen transmission. Exposure data from this study can be used to evaluate the effectiveness of measures to protect sanitation service workers.

Taking Container-Based Sanitation to Scale: Opportunities and Challenges

“…CBS services encompass the full sanitation value chain, and therefore meets the requirement for safely managed sanitation according to the WHO. Assuming feces are properly handled throughout the service chain, including treatment and safe disposal/reuse, CBS is likely to be an effective solution for limiting the spread of fecal contamination within household and community environments (Preneta et al, 2013;Russel et al, 2015;Foote et al, 2017;Mackinnon et al, 2018;Bischel et al, 2019).…”

Community Transmission of SARS-CoV-2 by Fomites: Risks and Risk Reduction Strategies

“…Quantitative Microbial Risk Analysis (QMRA) provides a framework for understanding health risks from indirect transmission and provides insights into potential impacts of infection control recommendations. Mechanistic models of transmission events within the context of QMRA frameworks have been used to identify risks for a number of scenarios including children playing with fomites 27 , sanitation workers collecting and processing urine for nutrient recovery 28 , and people sharing a houseboat. 29 Within the context of the current COVID-19 pandemic, QMRA has been adapted to evaluate and compare transmission risks for MERS-CoV and SARS-CoV-2 through droplets, aerosolized particles, and doffing personal protective equipment in hospitals [30][31][32] and to evaluate the effectiveness masks at reducing the risk of SARS-CoV-2 infection 33 .…”

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

“…Other strategy metrics, such as time taken or scheduling, could offer an alternative viewpoint on service characteristics. Another key consideration would be a strategy's potential health impacts on users and CBS operatives (Bischel et al 2019). Despite this, the results here suggest that economies of scale in the requisite routing for CBS provision will be largely conditional on greater collection capacity (rather than any particular provision strategy).…”