Graphene oxide addition to anaerobic digestion of waste activated sludge: Impact on methane production and removal of emerging contaminants

Abstract

The effect of graphene oxide on the anaerobic digestion of waste activated sludge was investigated at two graphene oxide concentrations (0.025 and 0.075 g graphene oxide per g volatile solids) using biochemical methane potential tests. The occurrence of 36 pharmaceuticals was monitored in the solid and liquid phases before and after the anaerobic treatment. The addition of graphene oxide improved the removal of most pharmaceuticals detected, even those that are considered persistent to biological degradation, such as azithromycin, carbamazepine, and diclofenac. No significant differences were observed in the final specific methane production without graphene oxide and with the lowest graphene oxide concentration, yet the highest graphene oxide concentration partially inhibited methane production. The relative abundance of antibiotic resistance genes was not affected by the graphene oxide addition. Finally, significant changes in the microbial community including bacteria and archaea were detected with graphene oxide addition

This research is funded by AEI (Agencia Estatal de Investigación, Spanish Government) through project ANTARES (PID 2019-110346RBC22). O. Casabella acknowledges funding from the Secretariat of Universities and Research from Generalitat de Catalunya and the European Social Fund for his FI fellowship (2022 FI_B1 00122). M. Gros acknowledges her Ramon y Cajal contract (RYC 2020-030324-I) funded by the MCIN/AEI 10.13039/501100011033 and by “ESF Investing in your future”. The authors acknowledge the support from the Economy and Knowledge Department of the Catalan Government through a Consolidated Research Group (ICRA-TECH - 2021 SGR 01283) and (SGR ICRAENV 2021 01282)

Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier

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