Investigation on mesophilic anaerobic co-digestion of community waste and cow dung: effect of operating parameters

Abstract

Management of waste is a key concern in several communities in Ghana. The exponential growth in waste generation imposes serious threats such as environmental pollution, health risk and scarcity of dumping site to our society. A large variety of organic rich materials inherent in this waste have high potential to be treated by the use of anaerobic digestion. In this study, eight (8) Laboratory scale biodigesters were used for the anaerobic co-digestion of household and market waste with cow dung as inoculum, controlled at a pH range of 6.53-7.04 and at a mesophilic temperature of 35±2˚C. The study was also conducted in batch mode at a hydraulic retention time of 21 days. The anaerobic co-digestion process was developed and optimized at varying feedstock to inoculum ratio to determine the potential biogas yield from each proportion. The results obtained indicate sample S8, containing market waste and inoculum in the ratio of 6:1 produced the optimum concentration of methane (51% v/v biogas) while the least was recorded by sample S2 primarily made up of market waste. ANOVA results show that the concentration of methane produced from the substrate is significantly affected by the hydraulic retention time and pH value of the anaerobic digestion process.