Spatiotemporal distribution, co-occurrence patterns, and potential effects of virulence factors in bioaerosols emitted from an Anaerobic-Anoxic-Aerobic wastewater treatment plant.

Bacterial pathogenicity poses a significant concern for both environmental and public health. Various virulence factors (VFs) contribute to the establishment and pathogenicity of bacteria, either independently or in combination. VFs are key indicators of the invasive potential of a pathogen. Increasing evidence suggests that municipal wastewater treatment plant (MWTP) act as both sinks and sources of pathogens and VFs. This study systematically evaluated the spatiotemporal distribution, co-occurrence patterns, and potential effects of pathogenic VFs in bioaerosols within a conventional anaerobic-anoxic-aerobic (A²/O) MWTP through longitudinal field monitoring. The results showed that after wastewater treatment, most VFs from wastewater were transferred to the dewatered sludge containing pathogens or host bacteria. During wastewater treatment and sludge dewatering, significant quantities of pathogenic VFs were released into the air. Pathogenic VFs were most abundant and stable in bioaerosols during the spring. Fine grid (FG) and sludge dewatering room (SDR) were identified as the primary units responsible for VF dissipation and pathogen accumulation. Pathogens significantly affected VF overexpression in bioaerosols, with strong positive symbiotic networks observed during all four seasons (54.14 %, 74.26 %, 59.77 %, and 59.82 %). In addition, the pathogenic VFs emitted from MWTPs were carried by wind, affecting the surrounding air quality. This study enhances understanding of the pollution caused by pathogenic VFs in MWTPs, providing important insights for assessing their environmental risks and formulating effective control strategies. It also contributes to safeguarding aquatic ecosystems and public health.