Aeration change from horizontal brush to fine bubble substantially reduces the emission of inhalable antibiotic resistome from wastewater to air.

Aeration-mediated aerosolization in wastewater treatment plants (WWTPs) poses considerable sanitary menaces. However, the effect of aeration patterns on the emission of inhalable antibiotic resistome in WWTPs remains poorly understood. Herein, we analyzed seasonal metagenomics of fine particulate matter (PM2.5) and wastewater under two aeration patterns, with consistent inflow condition, aeration efficiency, and location background in the same WWTP. PM2.5-borne antibiotic resistance genes (ARGs) exhibited higher occurrence, mobile potential, pathogen involvement, and resistome risks under horizontal brush aeration than under fine bubble aeration. And the airborne resistome risks peaked in winter. Regardless of aeration patterns, mobile ARGs in PM2.5 were mainly carried by integrases and resistant to macrolide-lincosamide-streptogramin. Totally, 6 pathogenic antibiotic resistant bacteria (PARB), including Klebsiella pneumoniae and Pseudomonas aeruginosa, expressed ARG mobility in aeration environments. Horizontal brush aeration drove 74.52% of the ARGs and 75.00% of the PARB from wastewater into the air, which were higher than the 57.53% of ARGs and 50.00% of PARB driven by fine bubble aeration. For aeration-related PM2.5 resistome, aeration patterns were the principal inducement through regulating bacterial community and PM2.5 concentration. These distinguish the aerosolization response of wastewater resistome to aeration patterns that can help process selection and hygiene protection.