This library entry contains background documents for a grant that Pete Kolsky and James Bartram are leading and which is funded by the Bill and Melinda Gates Foundation.

Further information is also available on the SuSanA discussion forum, see link below.

Short description of the project:
There is need to track human excreta beyond their initial deposit in toilets through to their final return to the environment, to ensure that the population is properly protected from the diseases spread by this waste.

The work of this project is intended to inform the expected Sustainable Development Goal Target to reduce the amount of human excreta unsafely returned to the environment. The “global scorecard” for excreta management developed will assist governments, funding agencies and development agencies to address progress and the need for improvement more effectively, both from an improved understanding of the situation, and from the clearer insight into the global situation.


We will model the return of human excreta to the environment through three sanitation technologies: pit latrines, septic tanks, and sewers. Similar to shit-flow diagrams, our model will track human excreta across the entire sanitation chain, including containment, emptying, transport, treatment, disposal/reuse. However, our model will also include both solid (fecal sludge) and liquid (wastewater/effluent) streams.

Rather than completing a mass balance of waste, as is done in shit-flow diagrams, our model will incorporate pathogen die-off over time and will therefore be representative of a “hazard balance”. The model will also classify the location of the hazard associated with unsafe return at each step in the sanitation delivery chain according to local, community, and the greater environment.

The tool is currently being developed at the national level, using disaggregated data for urban and rural areas and modeling each setting differently. However, it is anticipated that the model could be used at the regional and local level. The output of the model will assist policy makers by identifying where the greatest hazards are within the sanitation delivery chain and where exposure occurs, at the local, community, or environmental level. Policy-makers could then use tools like Sanipath to further identify specific exposure pathways within the local and community level.

to develop and pilot approaches for the estimation of the fraction of human excreta unsafely returned to the environment

- to estimate the fraction of human excreta unsafely returned to the environment, and
- to estimate where in the sanitation chain this occurs

Documents available for download below:

1 - Williams, A. R.; Overbo, A. (2015): Unsafe return of human excreta to the environment: A literature review. The Water Institute at UNC, Chapel Hill, NC, USA


Preview Image SFD

  download at

Various authors

Published in: 2015

Pages: 0

The Water Institute, Gillings School of Global Public Health (The University of North Carolina at Chapel Hill)

  • Presentations about SFDs in Africa and Indonesia

    Watch the presentation with voice on SFDs in Africa and Indonesia

    1. SFDs in Africa: From Visualization to Action

    2. How the Government of Indonesia is using the SFD

  • Global call for SFDs – Nov. – Dec. 2017

    Where are you standing in the SFD process? 

    We would like to offer you extra support, so you can either start preparing or complete your SFD and have it ready to be used for your purpose.

    Submit your SFD until December, 15th 2017!

  • SFD: The Indonesian Case (video)

    Watch the video (full version) on how the SFD was introduced in Indonesia and why the Indonesian government sees it as a useful tool to improve urban sanitation!

  • SFD Offline Graphic Generator

    You can now download SFD offline Graphic Generators for Windows and Mac.

  • SFD PI Update 5

    Check out the latest developments of SFD Promotion Initiative on the SuSanA Forum

  latest news