Reduction and characterization of bioaerosols in a wastewater treatment station via ventilation

Xuesong Guo , Pianpian Wu , Wenjie Ding , Weiyi Zhang , Lin Li


Received October 09, 2013,Revised November 13, 2013, Accepted , Available online August 28, 2014

Volume 26,2014,Pages 1575-1584

Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study, airborne microorganisms generated from a wastewater treatment station (WWTS) that uses an oxidation ditch processwere diminished by ventilation. Conventional sampling and detectionmethods combinedwith cloning/sequencing techniques were applied to determine the groups, concentrations, size distributions, and species diversity of airborne microorganisms before and after ventilation. There were 3021 ± 537 CFU/m3 of airborne bacteria and 926 ± 132 CFU/m3 of airborne fungi present in the WWTS bioaerosol. Results showed that the ventilation reduced airborne microorganisms significantly compared to the air in theWWTS. Over 60% of airborne bacteria and airborne fungi could be reduced after 4 hr of air exchange. The highest removal (92.1% for airborne bacteria and 89.1% for fungi) was achieved for 0.65-1.1 μmsized particles. The bioaerosol particles over 4.7 μmwere also reduced effectively. Large particles tended to be lost by gravitational settling and small particles were generally carried away, which led to the relatively easy reduction of bioaerosol particles 0.65-1.1 μm and over 4.7 μm in size. An obvious variation occurred in the structure of the bacterial communities when ventilationwas applied to control the airbornemicroorganisms in enclosed spaces.

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