Excreta Flow Diagram

Process Flow Diagram for the treatment of Human Excreta

The above process flow diagram (click here to download the diagram) provides a comprehensive collection of the different possibilities for the treatment of human excreta. The list of processes and their arrangement includes several technologies developed under the Re-invent the Toilet Challenge (funded by the Bill & Melinda Gates Foundation) as well as those followed in treatment plants, but is not exhaustive.

Guidelines for reading the diagram:


  • The blue squares displays the type of processes involved in the treatment of the excreta;
  • Next to some of the process, text provides more details about the different applied technologies;
  • The arrows gives an indication of the direction of the flow;
  • The blue dots indicate when one stream is divided, or when different streams meet into one;
  • The blue ovals shows the type of excreta and the final products after processing;
  • The orange ovals represent further products that can be obtained from excreta treatment;
  • The text in red font describes the different electricity and heat sources for the process;
  • The yellow ovals display the unwanted products (trash).