Identifying Emission Sources of Airborne Antibiotic Resistance Genes in Wastewater Treatment Plants Using CFD Simulation

Antibiotic resistance has become an increasing threat to public health. Previous studies on the airborne transmission of antibiotic resistance genes (ARGs) have primarily been rooted in microbiological approaches. Meanwhile, the physical processes governing the airborne dispersion of ARGs and airborne emission source identification remain poorly understood. This study proposes a novel interdisciplinary framework that integrates field measurement data analysis with computational fluid dynamics (CFD) to identify sources of airborne ARG emission in wastewater treatment plants (WWTPs). The approach was applied to a WWTP serving a large urban population. The CFD method was first validated with on-site wind data and then employed to simulate the aerosol dispersion from potential ARG sources. Simulated ARG distribution results were used to compare with real ARG distribution patterns obtained by qPCR and metagenomic sequencing from the on-site samples to identify the airborne ARG emission sources. Results showed the promise of CFD simulation for predicting the dispersion of ARG-containing aerosols in complex urban environments. Wind direction and downstream building layout played key roles in ARG dispersion. Among the three potential sources, sludge was identified as the primary contributor to airborne ARGs, while contributions from sewage in the flocculation tank and in the sedimentation tank were minimal. This study demonstrated the potential of CFD for physically interpretable ARG source identification, providing actionable insights for improving source control and developing future risk management strategies.