Static-magnetic-field coupled with fly-ash accelerant: A powerful strategy to significantly enhance the mesophilic anaerobic-co-digestion.

Abstract The anaerobic-co-digestion (AcoD) of dairy-manure (DM) and aloe-peel-residue (ALR) waste is enhanced by combining static-magnetic-field (SMF) and fly-ash (FA). Varying SMF intensities (5–30 mT) were applied to the co-digestion digesters containing the optimum FA concentration (1.5 wt.%), which were selected from co-digestion systems with a varying FA (0–2 wt.%). All experimental groups exhibit the greater COD removal rates (51.56–64.19%) and cumulative biogas yields (604.14–671.64 mL/g VS) than reference group (37.77% and 433.19 mL/g VS). The digester with optimum FA concentration (1.5 wt.%) under 5 mT shows the highest biogas yield (671.64 mL/g VS), and exhibits superior digestate stability (45.4%) and fertility (7.01%) for fertilizer utilization. A powerful strategy for understanding the underlying mechanism of the SMF and FA accelerant in an enhanced AcoD system is proposed. This work documents an innovative technique for an enhanced AcoD system using the SMF coupled with FA accelerant.