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.