Sanitation remains a great challenge of our time, especially in fast-growing cities of Africa and Asia. According to the UN, “in 2015, 29 per cent of the global population lacked safely managed drinking water supplies, and 61 per cent were without safely managed sanitation services". A lack of sanitation dramatically impairs public health, the environment, and development. Sanitation includes a chain of activities from private hygiene practices, to collection, treatment and disposal of wastes, either through a grid or non-grid system.
The UN have for the first time set a specific target on sanitation with the 6th sustainable development goal. Sanitation is a particularly complex topic, since it involves a large number of actors, a diversity of technologies, expands in public and private spaces, and relies on individual / collective behaviours based on an intimate practice that is taboo and little flexible.