SEEK (Sludge to Energy Enterprises in Kampala): co-processing faecal sludge for fuel production

The goal of this project was to improve the resource-recovery value of faecal sludge treatment products. A market assessment identified coffee husks, spent grain, and sawdust as optimal organic wastes to coprocess with faecal sludge to increase its fuel value. Drying times of faecal sludge to 90% solids were reduced by half with co-pelletizing with these organic wastes. Briquettes produced with char had comparable heating value, fuel performance, and emissions to charcoal briquettes currently being sold. Use of pellets as a fuel was tested in a gasifier and in several industrial clay kilns (after crushing). High ash content led to clinker formation in the gasifier, but performed well in kilns. The potential market for co-processed faecal sludge fuels is high in Kampala, Uganda, especially among industries, however, the market for pellets needs to be developed.