10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Size Distributions and Transport of Pathogenic Bioaerosol from Wastewater Treatment Plants
LIJIE LI, Xiao Huang, Hongliang Zhang, Michael Hoffmann, California Institute of Technology
Abstract Number: 1635 Working Group: Bioaerosols
Abstract Microbial pathogens transmitted by aerosols is a serious threat to public health as aerosols can transport in atmosphere and penetrate in human respiratory tract. Understanding the emissions and transport of pathogen-laden bioaerosol is of great importance in airborne infectious disease control. Wastewater treatment plants (WWTP) are fundamental facilities in urban environments and usually located in or adjacent to populated areas. Wastewater contains high concentrations of various microbial pathogens (e.g., pathogenic viruses, bacteria and protozoa) derived from human and animal wastes. Recent studies have found that the aerosolization of wastewater during the aerobic activated sludge treatment process produces a large amount of pathogenic bioaerosol, which can be transported hundreds of meters downwind. Therefore, WWTPs are a major source of pathogenic bioaerosol in urban area. The size distribution is the key parameter to determine the transport of bioaerosol in environment and human respiratory tract.
This work integrates the next-generation sequencing technique, high precision aerosol size differentiation instruments, and dispersion model to investigate the microbial composition, size distribution and transport of bioaerosol from WWTP. The aerosol number and volume distribution of total aerosol emission are measured online using an Aerodynamic Particle Sizer Spectrometer and Scanning Mobility Particle Sizer Spectrometer that include aerosols in the aerodynamic diameter from 10 nm to 10 μm. Size selected bioaerosols are collected near the aeration tanks for 4~5 hours at a local county sanitary district. The seasonal concentrations of total bacterial and bacteriophage MS2 extracted from sized aerosols are analyzed by real-time polymerase chain reaction (qPCR). The correlations between the distributions of microbe concentrations and aerosol number and volume are explored. Further, the microbial community structures and potential microbial pathogens associated with different sizes bioaerosol are analyzed by next-generation sequencing technique. The relationship between aerosol sizes and microbial composition as well as concentration is also discussed. By using the size distributions of aerosol number concentrations and microbe concentrations, the transport of potential pathogen riding on aerosol in atmosphere is predicted by the AERMOD dispersion model and the potential risk of bioaerosol exposure residents in nearby community is further evaluated by using International Committee for Radiological Protection (ICRP) lung deposition model. This work provides insights for the role of WWTP in pathogen transmission through airborne pathway.