Study On The Effect Of Turbulent Pulsation On The Growth Of Biofilm

Biofilm is a widely existed form of microorganisms in nature.Biofilm is applied to sewage treatment.The biofilm wastewater treatment technology has the advantages of abundant microbial species,good sedimentation and easy management,and strong adaptability to sewage water quality.The research on the factors affecting the growth of biofilm formation in biofilm method has been the focus of researchers.The vibrating grid device moves up and down in the water tank through the grille,which can generate approximate isotropic turbulence within a certain range.Because of this feature,the vibrating grid device is widely used for sediment start-up,sediment lifting and Research on stratified flows of oceans,atmospheres and lakes.In biofilm reactors,the growth and growth conditions of biofilm growth are often affected by both average flow and turbulent pulsation.At present,many scholars have paid much attention to the influence of hydraulic conditions on the growth of biofilm formation,but most of the research results are based on the coupling effect of both on the growth of biofilm,on the unilateral hydraulic conditions of turbulent pulsation for biofilm growth.Research is still rare.Based on the above research background,this paper uses a self-designed vibrating grid biofilm reactor unit.In this reactor flow field,the influence of turbulent pulsation factors on biofilm growth can be studied separately.By changing the operating frequency of the vibrating grid biofilm reactor,the turbulent intensity of the isotropic turbulent flow in the reactor is changed,and the growth characteristics of the isotropic turbulent intensity on the biofilm formation are analyzed by culturing the biofilm in the reactor.Impact.Through the analysis of experimental results,the main research results are as follows:(1)The vibrating grid biofilm reactor culture device was designed separately,and the reactor was operated at 0.5Hz,1.0Hz,1.5Hz,2.0Hz and 2.5Hz.It was proved that the designed isotropic homogeneity can be generated in the reactor.flow.The turbulence intensity of the biofilm carrier position in the reactor was determined to be 0.56 cm/s,1.45 cm/s,1.92 cm/s,2.54 cm/s and 3.10 cm/s at the five operating frequencies.(2)The biofilm was cultured under different turbulent intensity of the reactor,and the growth of biofilm under different turbulent conditions was observed.At 1.92 cm/s turbulence intensity,the biomass and growth thickness of the biofilm reached a maximum of 18.29.±0.8 mg,0.95±0.06 mm.The biofilm density was the maximum at a turbulent intensity of 2.54 cm/s,which was 32.14±0.5?g/mm ~3.(3)The increase of turbulence intensity in the vibrating grid biofilm reactor can promote the secretion of extracellular polymer by biofilm microorganisms.In the determination of EPS content of biofilm,the protein content is higher than that of polysaccharide,and the content of polysaccharide and protein is in turbulent intensity.The increase is always on the rise.(4)The biofilms under turbulence intensity of 0cm/s,1.45cm/s and 2.54cm/s were sequenced.It was found that the population structure of biofilm colonies growing under different turbulence intensity was different.Firmicutes,Bacteroidetes and Proteobacteria were biofilms.The main growth species(gate classification level),in the high turbulence intensity,is more conducive to the growth of bacteria of Cloacibacterium,Aeromonas,Flavobacterium.Biofilm species diversity indicates that biofilm bacteria exhibit higher diversity at 1.45 cm/s turbulence intensity.