Coconut-shell-derived bio-based carbon enhanced microbial electrolysis cells for upgrading anaerobic co-digestion of cow manure and aloe peel waste

[Display omitted] •MEC and CBC are combined to upgrade cow-manure-based anaerobic co-digestion.•MEC0.6CBC0.15 improves the methane yield by 120.68% and COD removal rate by 58.33%.•MEC with CBC demonstrates an excellent electrochemical activity.•Digestates exhibit an acceptable thermal stability and fertilizer efficiency.•A general strategy to understand enhanced performance of MEC with CBC is proposed. Microbial electrolysis cells (MECs) and exogenous accelerants can augment anaerobic digestion performance. Herein, MECs and coconut-shell-derived bio-based carbon (CBC) accelerant are adopted to strengthen anaerobic co-digestion of cow manure and aloe peel waste. The MEC with the voltage of 0.6 V and CBC accelerant of 0.15 wt.% gained the highest cumulative biogas yield (444.20 NmL/g VS) and chemical oxygen demand removal rate (75.46%), which are 80.25% and 58.33% higher than those (246.44 NmL/g VS, 47.66%) of the blank group, respectively. The digestates embodied a utilization potential with thermogravimetric loss of 37.12%–50.67% and total nutrient content of 35.36–51.58 g/kg. These results benefited from excellent electrocatalytic activity of MECs and physicochemical properties of CBC accelerant. A general strategy for understanding improved methanogenesis was proposed based on integrated effects of MECs and CBC accelerant. This work will shed light on development of anaerobic co-digestion by combining MECs and bio-based carbon accelerants.