Effectiveness of desiccation for faecal sludge volume reduction

Organisation: Aerosan

Partners: Université Laval, Quebec; Specific at Swansea University, UK

Location: TBC

Type of grant: Core – recognition

Status: Ongoing


Research at the Universities of Laval and Swansea will measure the effectiveness and efficiency of desiccation as a method for faecal sludge volume reduction in high density environments, leading to the re-design of Aerosan’s toilet so that the handling of waste is safer.

What is the humanitarian need?

Full pit latrines result in the need for pit replacement and emptying, which is a very costly activity in emergencies or very difficult to secure access to desludging equipment. Latrine emptying services often involve unsafe methods, which pose potential public health risks. As faeces is at least 75% water there are substantial cost savings (in addition to other benefits) to be made by eliminating the water content. The goal of this project is to determine optimal latrine design parameters for increased volume reduction through evaporation by making use of enhanced passive ventilation.

What is the innovative solution?

This project seeks to optimize faecal sludge desiccation by simple enhanced passive ventilation to reduce the waste to be taken off site by 75% in volume. By reducing the desludging frequency this project would substantially reduce the costs of desludging and quantities of faecal sludge that required handling. Addressing a volume reduction gap in emergency settings with benefits for latrine users in urban, peri-urban areas, and a refugee/IDP camp context. Moreover, the project could have other benefits such as the improvement of sludge handling characteristics and safety.

What are the expected outcomes?

First, the aid organizations providing sanitation for population in humanitarian emergencies will benefit from the outcomes of this project by significantly reducing their need for latrine maintenance and emptying requirements. Second, it will benefit people in internally displaced people (IDP) camps and other similar situations where sanitation is either non-existent or severely lacking. The project would also benefit pit latrine users in urban and rural environments.

The initial outcome of the ‘Recognition’ phase of the project would provide faecal sludge desiccation rates at varying conditions. This phase would serve subsequent model exercises to determine different configurations of the passive ventilation system. The outcome would be optimized prototype parameters to be validated in the field. Field-trials will validate design parameters. If successful, final optimized design parameters will be disseminated to WASH communities for implementation.


Elrha is hosted by Save the Children, a registered charity in England and Wales (213890) and Scotland (SC039570).

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