Research On The Pollution Characteristics And Control Technology Of Microbial Aerosol From Typical City Municipal Facilities

Municipal wastewater treatment plants plays an important role in treating sewage andmaintening ecological environment, More and more microbial aerosol emissions into the airwith application of biological treatment technology increased in the wastewater treatmentplant, in addition, microbial has the general hazards of aerosol, because these tiny particleshave a life activity, which spread in the air, may cause allergic disease and spread of epidemicdisease of human and animals. In recent years, microbial aerosol pollution get more and morepeople’s attention.In this paper, municipal wastewater treatment plant and urban solid waste comprehensivetreatment plant were chosen as research subjects, and concentrations of heterotrophic bacteria,fungi and actinomycetes in all functional areas were measured, discussed the weatherconditions effected on the concentration distribution of microbial aerosol. On this basis,removal of NH₃, H₂S and microbial aerosols with biofilter,to study the influence on removalefficiency of NH₃, H₂S and microbial aerosol under different operating conditions，at last,the removal mechanism of NH₃, H₂S and microbial aerosol was made.In the municipal wastewater treatment plant, there are some differences between theconcentration distribution of microbial aerosol in different seasons and different functionalareas, the total concentrations of microbial aerosol is: spring> autumn> winter> summer, theconcentration distribution of heterotrophic bacteria: spring> autumn> winter> summer, fungalconcentrations in the order: autumn> winter> spring> summer, the concentration distributionof actinomycetes: winter> spring> autumn> summer. In different functions area of sewagetreatment plants, the concentration of heterotrophic bacteria, fungi and actinomycetes mainlyconcentrated in the oxidation ditch, secondary sedimentation tank and sludge dewatering.In the urban solid waste comprehensive treatment plant, there are significant statisticaldifferences in concentration of airborne bacteria and fungi are detected between air samplescollect from different function areas （p<0.05）, their highest concentration are typicallydetermined in domestic waste aggregate room. According to evaluation criterion of airbornemicroorganism find that heterotrophic bacteria and fungi in different function areas havedifferent degrees of pollution. Particle size analysis show that heterotrophic bacteria indifferent function areas mainly concentrate in the stage1,stage2, stage3and stage4, and the fungi mainly concentrate in the stage3and stage4in different function areas, there are nosignificant differences （p>0.05） between the different function areas for both heterotrophicbacteria and fungi.Different meteorological condition had different influenced on the concentration ofmicrobial aerosol. In the experiment, when air temperature at28℃and relative humidity was30%, the concentration of heterotrophic bacteria, fungi and actinomycetes was highest, whenwind speed in the0-3.8m/s,the stronger of wind speed, the lower concentrations ofheterotrophic bacteria, fungi and actinomycetes.The best operating conditions for biofilter to removal NH₃, H₂S and microbial aerosolwas packing moisture content at60%-70%, inlet rate of1.5m³/h, the gas residence time of67.8s. and in the case of filling height range from30cm to90cm,the removal efficency ofNH₃, H₂S and microbial aerosol decreased with the fill height reduce, when the fill height was90cm, the purification of NH₃, H₂S and microbial aerosol got the best. The removal of NH₃,H₂S was mainly for the microbial biodegradation, while removal of microorganism aerosolwas mainly for the intercept effection of the filler.