Bacterial compositions in inhalable particulate matters from indoor and outdoor wastewater treatment processes

摘要

Wastewater treatment systems are critical microbial sources for urban air and play important roles in public health. In this study, bacterial communities in particulate matters (PM2.5, PM10) from wastewater/sludge treatment facilities of two full-scale wastewater treatment plants were analyzed by 16S rRNA amplicon sequencing. Compared to the background ambient air, Campylobacteriadeceae, Aeromonadaceae, and Chlostridiaceae were the most enriched bacteria above wastewater treatment facilities. In sludge dewatering facilities, Comamonadaceae, Chitinophagaceae, Caldilineaceae, Mycobacteriaceae, Methylocystaceae, Microbacteriaceae, Cryomorphaceae, and uncultured Class OPB56 were the most enriched. The dynamic bacterial compositions in aerosols were contributed by aerosolization and dispersion. Principal coordinate analysis and clustering analysis showed that the aerosol bacterial community from indoor sludge treatment were closely clustered with that of sludge, indicating that aerosolization dominated the indoor environments. In contrast, aerosols from outdoor wastewater treatment facilities clustered with background ambient aerosols, indicating that outdoor aerosol bacterial communities were mainly governed by dispersion. Aerosolization factor (the ratio of bacteria abundance in aerosols to those in wastewater/sludge) was used to evaluate the aerosolization potential and survival of bacteria. Rhodocyclaceae, Arcobacter, Comamonadaceae, Mycobacterium, and Citrobacter were not only preferentially aerosolized from wastewater/sludge, but also sustainable during dispersion in ambient air.