This study proposes a method of recovery by co-composting of dehydrated faecal sludge (DFS) and solid organic household wastes (SOHW) in Ouagadougou. The city has three drying bed treatment stations which are partially functioning because after the liquid/solid separation, the bio-solids are piled up without final treatment and currently constitute a major risk of pollution. This research aims to propose an appropriate treatment chain for dehydrated faecal sludge in the Ouagadougou stations. The solution tested in this study is the co-composting of DFS with co-substrates which are SOHW. These wastes were put in co-composting in windrows marked A1, A2 and A3, corresponding to the mixing ratio mass of SOHW/DFS respectively 2/1, 3/1 and 4/1. Physicochemical parameters were monitored to appreciate the process progression and maturity of the composts. To confirm the results of maturity, germination tests were carried out on Okra. The results show a normal biodegradation of organic matter with peak average temperature of 68 °C, 68 °C and 66 °C respectively for windrows A1, A2 and A3. The monitoring of the C/N and NO3- ∕NH4+ ratios for the windrows of the same formulation allows us to conclude that, when a repeat windrows of the same formulation is made, it obtains substantially the same evolution of the ratios C/N et NO3−/NH4+. Considering the C/N and NO3- ∕NH4+ ratios, all composts could be declared mature. However, the germination index shows that the A3 formulation composts are not mature. Globally, compared to the other windrows, the A2 (3/1) formulation composts gave better results.

Co-composting · Dehydrated faecal sludge · Organic household solid waste physicochemical parameters