Assessing genetic structure, diversity of bacterial aerosol from aeration system in an oxidation ditch wastewater treatment plant by culture methods and bio-molecular tools

Abstract

Airborne bacteria emissions from oxidation ditch with rotating aeration brushes were investigated in a municipal wastewater treatment plant in Beijing, China. Microbial samples were collected at different distances from the rotating brushes, different heights above the water surface, and different operation state over a 3-month period (April, May, and June) in order to estimate the seasonal variation and site-related distribution characteristics of the microorganisms present. The concentration of bacterial aerosol was analyzed by culture methods, while their dominant species, genetic structure and diversity were assayed using bio-molecular tools. Results showed that total microbial concentrations were highest in June and lowest in April. The mechanical rotation caused remarkable variation in concentration and diversity of culturable airborne bacteria before and after the rotating brushes. The highest concentration was observed near the rotating brushes (931±129-3,952±730 CFU/m 3 ), with concentration decreasing as distance and height increased. Bacterial community polymerase chain reaction and denaturing gradient gel electrophoresis indicated that diversity decreased gradually with increasing height above the water surface but remained relatively constant at the same height. All dominant bacteria identified by DNA sequence analysis belonged to Firmicutes. Pathogenic species such as Moraxella nonliquefaciens and Flavobacterium odoratum were isolated from the bioaerosols. Due to the serious health risks involved, exposure of sewage workers to airborne microorganisms caused by brush aerators should be monitored and controlled.

Aerosolization of Ebola Virus Surrogates in Wastewater Systems

“…While other studies have reported concentrations of airborne bacteria around WWTPs, 24,27,30,32 fewer have focused on airborne viruses. 34,40 Our results show that viable virus can be aerosolized from an aeration basin.…”

“…These aerosolized microorganisms can maintain their viability and spread in ambient air. 28,29,31,32 The potential for EBOV to spread via this route is not known. Previous studies have focused mainly on bacteria rather than viruses, and they have not measured the full range of aerosol sizes produced by flush toilets.…”

“…22 Bacterial and fungi, including pathogenic ones, have been detected in the surrounding air, [23][24][25][26][27][28][29][30][31][32] demonstrating that wastewater treatment processes have the potential to generate bioaerosols. However, few studies have focused on aerosolization of viruses in wastewater systems.…”

Site-related and seasonal variation of bioaerosol emission in an indoor wastewater treatment station: level, characteristics of particle size, and microbial structure

“…Airborne bacteria and fungi generated from an Orbal oxidation ditch in a wastewater treatment plant in Beijing were investigated, and 3952 ± 730 CFU/ m 3 of airborne bacteria were detected from the point near the rotating brushes in June (Li et al 2013). Approximately 8 9 10 4 m 3 /day water was treated in the WWTP.…”

“…The concentration of airborne Mean concentration and standard deviation in S1(CFU/m 3 air) S1 S2 Fig. 4 Site-related emission of airborne bacteria and fungi in June bacteria was investigated in an Orbal oxidation ditch in a Beijing municipal WWTP, and outcome demonstrated that the airborne bacteria decreased dramatically with increasing distance from the rotating brushes (Li et al 2013). The concentrations of airborne bacteria and fungi that emerged in the air increased with increasing proximity to the bioaerosol source.…”