Co-digestibility of wastewater and faecal sludge in anaerobic treatment (Uganda)

Recovery and utilization of renewable energy such as biochemical methane through anaerobic mono/co-digestion of wastewater sludge and faecal sludge with other organic feedstocks such as food waste and agricultural waste, could provide an alternative for an efficient, cost-effective, sustainable and eco-friendly source of energy. Optimizing the anaerobic digestion process is a prerequisite for improving the digestibility and the subsequent biochemical methane yield that would meet the energy requirement of wastewater and faecal sludge treatment facilities. The research concluded that optimization of the organic loading rate, and mixing ratio of wastewater sludge and the co-feedstock(s) would effectively enhance and improve the biodegradability potential of wastewater sludge. This might result in an increase in biochemical methane yield, hence offsetting the overall energy cost of the wastewater treatment facility. The research recommended the use of co-feedstock(s) such as food waste and/or market waste with higher biochemical methane potential and low nutrient concentration than wastewater sludge and faecal sludge; accessibility and variation of the co- feedstock(s), transportation costs, quality of digestate and regulatory standards for reuse and disposal should all be considered when planning a co-digestion project.