The impact of reduced graphene oxide (rGO) supplementation on cattle manure anaerobic digestion: Focusing on process performance and microbial syntrophy

Abstract At a time when there is a surge in demand for increasing renewable energy production, boosting biomethane production per unit organic matter/waste has become a big challenge and necessity. In this study, the effect of rGO addition on biomethane production from cow manure under mesophilic-batch conditions was investigated. Biomethane production was increased via rGO supplementation at appropriate concentrations. The highest biomethane production, which was 335 mL/gVSad (65 % increase), was obtained by adding 20 mg/L rGO (CM20) while rGO addition slightly increased (up to 5.4 %) the CH4 content of biogas. The microbial community analysis indicated that via rGO supplementation, the dominant bacteria changed from Levilinea to Candidatus Cloacamonas and a more diverse archaeal community was formed. According to this study results, rGO supplementation could be used at biogas plants to boost renewable energy production.