Evaluation of bacterial bioaerosols and their relationship with environmental factors in the air of the wastewater treatment plant of industrial

Abstract

Bioaerosol emissions from wastewater treatment plants (WWTPs) can pose a potential risk to human health and the environment. This study aimed to identify and analyze the dominant bacterial species in airborne bioaerosols at the Jahanabad Industrial Zone WWTPs in Meybod, and to examine their relationship with environmental factors. This study was conducted in the spring and summer of 2020 at the Jahanabad Industrial WWTP in Meybod. Over a period of 6 months, 96 bacterial bioaerosol samples were collected using an Anderson device, and environmental parameters were measured simultaneously. After differential tests and examination of phenotypic characteristics, the dominant colonies were maintained in TSB medium with 30 glycerol and confirmed by PCR. A total of 19 bacterial species belonging to 5 genera were identified through sequencing. The most dominant genus observed was Bacillus (52.6), followed by Kocuria (26.3) and Micrococcus (10.5). The equalization tank (ET) exhibited the highest mean concentrations (176.98 +/- 12.37 CFU/m(3); 75.13 +/- 5.25 CFU/plate), while the lowest levels were observed 100 m downstream (100D) of the treatment plant (36.81 +/- 13.89 CFU/m(3); 15.63 +/- 5.89 CFU/plate). No significant correlation was found between bioaerosol concentrations and wind speed (r = - 0.08, p = 0.44). However, a significant positive correlation was observed with relative humidity (r = 0.51, p < 0.001), and significant negative correlations were found with Temperature (r = - 0.56, p < 0.001), UVA (r = - 0.51, p < 0.001), and UVC radiation (r = - 0.59, p < 0.001). This study demonstrated that industrial WWTPs, regardless of variations in wastewater characteristics, possess a high potential for emitting bacterial bioaerosols into the environment, posing potential risks to both worker health and the surrounding ecosystem.