Nanoferrosonication: A novel strategy for intensifying the methanogenic process in sewage sludge.

Graphical abstract Highlights • Nanoferrosonication (NFS) pretreatment was studied. • NFS was evaluated to improve the solubilization and anaerobic digestion of sludge. • Anaerobic tests were conducted at 15,000 and 25,000 kJ/kg TS with 2 and 7 mgFe0/g VS. • The biogas yield increased from 106 to 308 mL/g VS with 7 mgFe0/g VS + 15,000 kJ/kg TS. • The results demonstrated that NFS was effective in intensifying the process. Abstract In this work, the effect of coupling ultrasonic pretreatment with dosing of zero-valent iron nanoparticles (nanoferrosonication, "NFS") to improve the anaerobic digestion of sewage sludge was studied. Biochemical methane potential tests were conducted at 15,000 and 25,000 kJ/kg TS and their combinations with 2 and 7 mgFe0/g VS. The biogas yield increased from 106 (control) to 143 (25,000 kJ/kg TS) and 308 mL/g VS with NFS (7 mgFe0/g VS + 15,000 kJ/kg TS). The methane content increased from 55.6 to 66%, and the maximum VS removal was 11.5% at 7 mgFe0/g VS + 15,000 kJ/kg TS. The results demonstrated that NFS was effective in intensifying the process. [ABSTRACT FROM AUTHOR]