Impact of adding agricultural waste to the fuel potential of faecal sludge (Kenya)

There is an urgent need to switch to alternative cooking fuels and sustainable FSM in Kenya. In alignment with SDG 6 and SDG 7, this research studied the impact and viability of co-managing two organic waste streams, as potential household cooking fuel. The FS samples were categorised as raw and mixed (blended with corncob in equal proportion) to understand their combustion behaviour. They were analysed for volatile and fixed solids, calorific value, and organic and inorganic elemental composition. The study concluded that the organic composition of FS is consistent across sanitation technologies and the variability associated with FS is from its inorganic composition attributing from sanitation practices and operational differences in on-site sanitation technologies. The study verified the additive law for theoretical estimation of the properties, meaning that the final value of a property will be the weighted average of an individual raw sample. This decreases the dependency on extensive laboratory analysis, and can be used as a proxy to determine the efficient and workable mixing ratios for the required end-product. Lastly, an attempt was made to develop a correlation prediction model explicitly for FS and successfully established the relationship between its higher heating value and elemental composition. As a result, higher heating value of FS can be predicted with mean absolute percentage error of ±4.9%.