This case study presents an innovative initiative to facilitate safe reuse of faecal sludge (FS) by introducing the World Health Organisation's multi-barrier approach within a Farmer Field Schools framework for participatory experiential learning. A novel FS treatment process based on fermentation by ‘effective organisms’ (EM) was piloted to test the feasibility, safety and acceptability of the resulting fertilizer. Fermented FS in agricultural application was found to perform at least as well as other common fertilizers it was compared with, while its lower cost delivered higher profits per cultivated hectare. Participating farmers found it easy to prepare and use, and viewed it favourably overall. EM-based fermentation was, however, found to be insufficient as an FS treatment to render safe reuse, particularly with respect to helminth inactivation. The paper discusses strengthening the treatment barrier, and improving the application of the multi-barrier approach by the systematic consideration of non-treatment barriers using guidance from the WHO's Sanitation Safety Planning Manual. Further research to enable effective monitoring and support systems for maintaining treatment and non-treatment barriers, and for understanding long term impacts of fermented FS application is recommended. In combination, adequately treated fermented FS may be a candidate for scale up necessary for meeting the Sustainable Development Goals.