Three things we have learned by creating shit-flow diagrams. WaterAid Blog, June 2019.
How do you get a full picture of how a city deals (or doesn’t deal) with its waste? Rémi Kaupp, urban sanitation specialist, swears by shit flow diagrams…
Think about your city. Hundreds, thousands, maybe millions of people, going to the toilet, every day. Do you know where it all goes after the toilet? And, crucially, do you know how much of it is treated?
In many cities where WaterAid works, the answer is: not really. Authorities might have a rough estimate of the proportion of people who have a toilet, and also know where treatment plants are, if there are any – but that’s not the whole picture.
Introducing: the shit flow diagram
To get the full view, my colleagues have been using one of my favourite tools in sanitation: the shit-flow diagram (also called SFD, or ‘excreta-flow diagram’, if you prefer). An SFD looks like the festive picture below. For a given city, green arrows represent the proportions of excreta that are ‘safely managed’ along the whole sanitation chain: from the toilet, through a pit or septic tank, via sewers or sludge tankers, to treatment stations and eventual disposal or reuse.
Read the complete article.