Bioaerosols at wastewater treatment facilities: sources, composition, sanitary and epidemiological risks (a review)

Summary

Attention to the issue of bioaerosol emissions in the process of wastewater treatment has increased with reports about wastewater aerosolization as a potential source of SARS-CoV-2 virus exposure to the air during the recent COVID-19 pandemic; however, the impact of exposure to bioaerosols on the health of the people with compromised immunity, personnel of treatment facilities and population of adjacent territories has been reported earlier. Emission of bioaerosols occurs at various stages of the technological process (mechanical treatment, biological treatment, wastewater sludge treatment). The amount of bioaerosols formed depends on the hydrodynamic conditions of wastewater treatment, type of treatment plant (closed or open), wastewater composition, treatment technology used, technical characteristics of the equipment, capacity of the treatment facilities, operating conditions, aeration rate and mode, concentration of biomass and growth phase of microorganisms. Bioaerosols contain pathogenic bacteria including those resistant to antibiotics, fungi that are potential pathogens of mycetogenic diseases, as well as viruses that can survive for a long period of time in wastewater and are spread by airborne transmission. The applied methods of bioaerosol analysis provide data on the presence, size and viability of aerosol microorganisms; however, until now no standard methodology for sampling bioaerosols has been available. Thermal treatment and ultraviolet irradiation, the use of air filters and ventilation have become widespread among the means of preventing the formation and spread of bioaerosols. Various research in this area has focused on the use of granular activated carbon, floating plastic balls for water surface isolation, reactor surface vacuum treatment, wastewater sludge composting using membrane coating, the use of biofilters, and installation of wind barriers along the boundaries of wastewater treatment facilities and vertical gardening systems.

Key words

wastewater , viruses , bacteria , treatment facilities , bioaerosols , fungi