Association of magnetic-flyash in anaerobic co-digestion for biomethane optimization: Promoting biofilm formation

Abstract

The application of low-cost magnetic industrial wastes as accelerants can significantly improve the performance of anaerobic co-digestion (AcoD), thereby enhancing the biogas yield. In this work, varying concentrations (1.0–4.0 wt.%) of magnetic flyash (MFA) were applied to the AcoD of cow manure (CM) and aloe peel waste (APW). All AcoD systems were operated under mesophilic condition (37 ᴼC) with a 5 mT magnetic field. The AcoD system with 2.0 wt.% of MFA showed the highest cumulative biogas yield (487 mL/g VS), methane content (65.17%), COD, TS and VS removal rates (36.45, 45.49 and 52.10%, respectively), and fertility (3.4%). However, the 1.0 wt.% of NMFA also showed higher cumulative biogas yield (432 mL/g VS), methane content (60.23%), COD, TS and VS (27.69, 18.24 and 43.64%, respectively), and fertility (3.31%) than other NMFA concentrations (1.5 & 2.0 wt.%). Kinetic models verified that MFA coupled with a magnetic field could increase biogas potential and production rate. A strategy for determining the role of MFA in microbial biofilm formation and improving biodegradation, which increases the biogas yield, is also suggested. This work demonstrates a cost-effective application of MFA in bioenergy production systems by improving the AD process.