Practical Paper Time and motion assessment of pit-emptying operations in Kigali, Rwanda Bruce Rutayisire a, * , Dennis Wolter a , Nicholas Kuria a and Rachel Sklar b a Pit Pumpers Ltd, Kigali, Rwanda b Environmental Health Sciences Division, School of Public Health, University of California, Berkeley, CA 94720, USA *Corresponding author. E-mails: bruce@pitvidura.com; brucerutayisire@gmail.com BR, 0000-0003-0180-5292; RS, 0000-0001-8574-9456 ABSTRACT To ensure sanitation for all by 2030, fecal sludge collection services in low-income urban areas with no sewer connections need improvement. One of the major issues is the gap between low-income households’ willingness to pay and the cost of emptying services in low-income areas. One way of lowering the cost of these services is through process optimization. In this regard, we conducted a time and motion study to better understand the bottlenecks associated with the collection of fecal waste from different types of on-site sanitation facilities. Our results show that emptying pit latrines, which make up 53% of the market for emptying services in Kigali, takes twice as long as emptying septic tanks. 33% of households that requested the service were located in an informal settlement with no access to road and could only be served by a semi-mechanized method which required use of barrels, and a portable pump. In general, interventions related to minimizing trash disposal in pits and septic tanks can go a long way in making the emptying process more time- and cost-efficient. Additionally, developing effective and efficient pumping technologies that are suitable for use in inaccessible areas should be prioritized. Key words: FSM, on-site sanitation, pit latrines, septic tanks, time-motion study, trash fishing HIGHLIGHTS • Pit-emptying process time varies depending on the type of pit and on the type of emptying method used. • By applying time and motion study, we can improve fecal sludge collection process duration. INTRODUCTION With the UN Sustainable Development Goal of ensuring sanitation for all by 2030 (SDG6), the demand for new ways to safely collect, transport, and dispose of fecal waste from household sanitation facilities is increasing (United Nations Publications 2020). This is especially true as traditional sewage infrastructure remains unaffordable for households and governments in most low-income contexts (Dodane et al. 2012; Brunner et al. 2018). Around 2.7 billion people use on-site sanitation world- wide, where an estimated 1.77 billion use some form of pit latrine as their primary means of excreta disposal (Graham Jay & Polizzotto Matthew 2013; Strande & Brdjanovic 2014). These systems generally require an emptying service to excavate waste from the full pit or tank, especially when space is limited or the construction cost of a new one is high (Strauss et al. 2000). Such services are provided by the private sector using manual emptying (unhygienic emptying), manually driven mechanical systems, or vacuum tankers (hygienic emptying) (Still et al. 2012). In many emerging urban markets, there is a large discrepancy between low-income households’ willingness to pay and the cost of delivering emptying services in low-income areas (Burt et al. 2019). While manual emptying is less expensive than existing mechanical emptying (Sisco et al. 2017), manual emptying is illegal due to unsafe and unhygienic practices that put worker and community health at risk (Thye et al. 2011). There is a dire need for affordable and safe emptying services. To date, efforts to make emptying more affordable have focused on the development of new hardware for extracting fecal sludge (Muller & Rijnsburger 1992; Tilley et al. 2014). Other research has explored cost subsidizing, clustering, and the This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/). © 2021 The Authors Journal of Water, Sanitation and Hygiene for Development Vol 00 No 0, 1 doi: 10.2166/washdev.2021.079 corrected Proof Downloaded from http://iwaponline.com/washdev/article-pdf/doi/10.2166/washdev.2021.079/980834/washdev2021079.pdf by guest on 24 December 2021