Sewage sludge co-digestion with mango peel liquor: impact of hydraulic retention time on methane yield and bioenergy recovery

As the shift towards renewable energy sources continues, new approaches for energy recovery from sewage sludge must be established. This paper explores the feasibility of implementing full-scale co-digestion of municipal sewage sludge with fruit biowaste through the synergetic effects obtained at the laboratory scale. The efficiency/stability of the process was studied for three hydraulic retention times. By using simple tools to evaluate the performance of the anaerobic digestion system, such as the specific methane indicator and the energy potential recovery indicator, it was shown that the shortest retention time of 13 days had the highest methane production and almost doubled the specific methane production, thus contributing to sustainable waste management and energy self-sufficiency of wastewater treatment plants.