Research Paper Field demonstration of breathable laminate-lined container-based toilets in Kanpur, India Shray Saxena, Puneet K. Srivastava, Steven K. Dentel, Paul T. Imhoff and Daniel K. Cha ABSTRACT Drying of fecal sludge (FS) enclosed in a breathable, hydrophobic membrane laminate was investigated in 208 and 40 L container-based toilet (CBS) systems referred to as Eco-Vapor toilets (EVTs). EVTs were constructed and pilot tested in four households in urban slums of Kanpur, India over a period of 2 years. The average moisture losses of 0.8 and 0.9 kg/day were observed in laminate-lined 208 L drums for Year 1 tests, and this in situ drying decreases disposal frequency by 8 days compared with CBS that do not allow FS drying. In Year 2, smaller EVTs with 40 L laminate- lined drums and waste segregation increased replacement time over conventional CBS by 45%, as opposed to the 19% increase observed in Year 1 tests. Despite its limitations, the stagnant film model using meteorological data predicted the mass-loss rate within 52 and 28% error for the 208 and 40 L drums, respectively. Key words | breathable laminate, Eco-Vapor toilets, fecal sludge, stagnant film model HIGHLIGHTS • Eco-Vapor toilets (EVTs) use breathable laminate-lined drums to store and dry fecal sludge. • Drying rates of 40 L containers were higher than those of 208 L drums. • In situ drying in the 40 L EVT extended the replacement time by 45%. • The stagnant film model predicted mass-loss rates within 28% error for the 40 L EVT. Shray Saxena Steven K. Dentel † Paul T. Imhoff Daniel K. Cha (corresponding author) Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716, USA E-mail: cha@udel.edu Puneet K. Srivastava WaterAid India, 2/203, Vishal Khand, Gomti Nagar, Lucknow, Uttar Pradesh 226010, India Shray Saxena Department of Science and Mathematics, Texas A&M University – San Antonio, San Antonio, TX, USA † Deceased This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY-NC-ND 4.0), which permits copying and redistribution for non-commercial purposes with no derivatives, provided the original work is properly cited (http://creativecommons.org/ licenses/by-nc-nd/4.0/). 505 Research Paper © 2021 The Authors Journal of Water, Sanitation and Hygiene for Development | 11.3 | 2021 doi: 10.2166/washdev.2021.011 Downloaded from http://iwaponline.com/washdev/article-pdf/11/3/505/890033/washdev0110505.pdf by guest on 01 February 2022