Correlation between Key Organic Substrate Characteristics and Biogas Production

Abstract

In this study, wastewater sludge (WW), foodwaste (FW) and fats, oils and grease (FOG) were characterized and mono digested. Out of the three feedstocks, 10 subsamples were prepared using volume to volume ratios and co-digested. The study was carried out with biomethane potential assays operating at mesophilic temperature. At the end of the experiments, wastewater mono digestion yielded the lowest specific methane of 118ml CH4/g VS while the co-digestion of 50% WW and 50% FOG gave the highest specific methane of 1040ml CH4/g VS. In general, all co-digestion assays yielded higher methane compared to mono digestion assays. Also, lipid-rich samples produced more biogas than samples rich in proteins and carbohydrates. However, samples rich in proteins and carbohydrates had faster gas production rate than lipid-rich samples. Overall, co-digestion of substrates with good proportion of lipids, proteins and carbohydrates lead to significant biogas output.