Enhanced methane production in anaerobic co-digestion systems with modified black phosphorus

•MBP as accelerant were used in AcoD and MEC-AcoD system firstly.•MBP coupled with MEC system improved anaerobic co-digestion performance.•MEC0.6MBP0.03 increased the biogas yield (387.6 mL/g VS) and TCOD removal (71.5 %).•MEC0.6MBP0.03 enhanced the CH4 production (62.5%) and CO2 reduction (25.2%).•TP content of MEC0.6MBP0.03 (1.74%) compared to commercial fertilizer (2.54%).•A strategy for enhanced CH4 production and CO2 reduction in AD systems is proposed.