Field demonstration of breathable laminate-lined container-based toilets in Kanpur, India

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. 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.;

Keywords

• breathable laminate
• eco-vapor toilets
• fecal sludge
• stagnant film model