Study On Distribution Characteristics Of Atmospheric Microbial Aerosols In Typical Areas Of A Municipal Wastewater Treatment Plant

Microbial aerosols are aerosols containing biological particles that are surrounded by all human activities.Microbial aerosols can enter the human body through skin contact,respiratory inhalation,etc.,and the harmful pathogenic microorganisms can pose a serious threat to human health.In recent years,diseases with microbial aerosols as vectors have frequently occurred,such as SARS and influenza A,which have attracted widespread attention from domestic and foreign scholars on microbial aerosols.As a key pollution source of urban microbial aerosols,urban sewage treatment plants have attracted more and more attention from the society.In the sewage treatment plant,microbial aerosols are released into the air during the sewage treatment process,which poses a potential threat to the workers of the sewage plant and the surrounding dwellings.This study mainly uses Anderson six-level microbial sampler to detect different areas of a city sewage treatment plant in Lanzhou,study the concentration distribution characteristics and particle size distribution characteristics of microbial aerosols in urban sewage plants,and explore microbial aerosols and temperature,relative humidity,Correlation of influencing factors such as PM2.5 and PM 10,the results of the study:(1)The microbial aerosols in urban sewage treatment plants are:bacterial aerosol>fungal aerosol>actinomycete aerosol.The concentration of bacteria,fungi,actinomycetes and the pollution evaluation at each sampling point were:sludge dewatering room>grid room>aeration tank>background control point.The monthly variation trend of different microorganisms is similar,and the daily variation is mainly characterized by the distribution of morning and evening high and noon.According to the air microbial standard standard formulated by the Ecological Research Center of the Chinese Academy of Sciences,the bacterial and total microbial contamination status of sludge dewatering is the most serious,and it is in a state of micro-pollution or heavy pollution,and the background control point is basically kept clean.(2)The particle size of bacterial aerosol in sewage treatment plant is mainly concentrated above 3.3 ?m,and the aerosol particle size of fungi and actinomycetes is mainly distributed in the range of 2.1-7.0 ?m.The microbial aerosol particle size distribution of the processing unit with high-speed mechanical operation(sludge dewatering room,grid)is smaller than the background control point and the aeration tank.In the study of the microbial aerosol median diameter of the wastewater treatment plant,the median diameter of the bacteria ranged from 2.65 to 4.67 ?m,the fungal median diameter ranged from 3.29 to 4.50?m,and the median diameter of the actinomycetes ranged from 3.15.Between-4.32 ?m,the bacterial aerosol median diameter between sludge dewatering is much smaller than other sampling points.In studies of inhalable microbial aerosols(0.65-4.7 ?m),bacterial aerosol particles were found between 51.99 and 85.36%,fungal aerosol particles were between 53.74 and 85.08%,and actinomy aerosol particles were present.Between 56.41-82.07%.(3)The changes in the value of the Person coefficient of bacteria,fungi and actinomycetes in the sewage plant have similarities.Microbial aerosols at various sampling points in spring and autumn were positively correlated with temperature.Microbial aerosols at various sampling points in summer and winter wastewater plants were negatively correlated with temperature.The main reason was that excessively high and too low temperatures were bacterial enzyme denaturation;microbial aerosol concentrations.It is basically positively correlated with the relative humidity of the air,indicating that the air humidity is favorable for growth.The concentration of atmospheric microbial aerosols is within a certain range,which increases with the increase of PM2.5 and PM10,indicating that the microbial aerosols in the wastewater treatment plant interact with airborne particulate matter.Through multivariate linear programming,it is found that the important environmental factors affecting microbial aerosols in urban sewage treatment plants vary with the seasons.In general,the important factors of bacteria,actinomycetes and total microorganisms are PM2.5,and the important factor affecting fungi is temperature.