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

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.

Keywords: Anaerobic digestion; Nanoferrosonication; Sewage sludge; Ultrasonic pretreatment; Zero-valent iron nanoparticles.