| Chlorobenzene（CB）,as a typical chlorinated volatile organic compound（CVOCs）,is mainly synthesized artificially and used as a raw material for dyes,medicines,perfumes and pesticides.CVOCs cause the destruction of the ozone layer,the formation of secondary particulate PM2.5 and photochemical smog precursors.The accumulation of CVOCs in the organism increases the health risks of liver and pancreatic cancer.Compared with physical and chemical methods,biological treatment methods are more economical and environmentally friendly,and are the most commonly used method for treating CVOCs waste gas.Biological trickling filter（BTF）has high removal efficiency,strong resistance to load impact and easy control of reaction conditions,etc.,and is widely used in organic waste gas purification.The gas-liquid mass transfer resistance of chlorobenzene is the main limiting factor for the purification performance of BTF.The addition of the surfactant rhamnolipid can improve the purification performance of BTF to a certain extent.At the same time,the construction of a three-phase mass transfer degradation model of BTF is important for BTF design and The reactor performance prediction is of guiding significance.The research results are of great significance for CVOCs pollution control and the industrial application of biological trickling technology.In this thesis,chlorobenzene is used as the target pollutant,coking wastewater activated sludge is taken as the source of bacteria,and the chlorobenzene degrading bacteria strain is domesticated;through the theoretical analysis of the mass transfer process and biological reaction mechanism of the biological trickling filter,combined with the operating characteristics of BTF,The gas-liquid-biofilm three-phase steady-state dynamics model was established,and the MATLAB software was used to program and solve it.The test examines the BTF start-up and stable operation process performance parameters,and judges the accuracy and applicability of the model by comparing the model simulation data with the test data.Use gas chromatography（GC）,Zeta potentiometer,Fourier infrared spectrometer（FTIR）,etc.to analyze the effects of the addition of rhamnolipids on the composition,content and surface characteristics of biofilms,and study the enhancement of rhamnolipids to BTF performance effect.The main findings are as follows:（1）Propose modeling hypotheses based on the mass transfer flux between gas and liquid and the degradation rate of biological reactions,and establish gas-liquid-biofilm based on the mass transfer,liquid phase equilibrium and biofilm phase degradation quality equations Three-phase steady-state dynamics model.Using the finite difference method（bvp5c）and the fourth and fifth-order Runge-Kutta method（ode45）in MATLAB software to solve the biofilm phase degradation equation and the gas-liquid mass transfer equation set,the steady-state chlorobenzene concentration along the height of the BTF packing Distribution.The Michaelis-Menten kinetic equation was used to perform regression fitting,and the maximum comparative solution rate of mixed bacteria was obtained as 0.165g˙g-1˙h-1.（2）The start-up phase of the BTF was completed in 26d.At steady state,the removal efficiency of chlorobenzene with an intake concentration of 800 mg·m-3reached 88.95%,and the removal load was 21 g·m-3h-1.Investigate the influence of various process parameters on the removal performance of BTF during the stable operation period.When the concentration of chlorobenzene waste gas is maintained at1 g·m-3and the EBRT is 120,90 and 60 s,the corresponding removal rates are 86%,73%and 57%,The removal load of chlorobenzene is 25,29 and 35g·m-3h-1;when EBRT 60 s,the chlorobenzene concentration is 0.75,0.5,0.25 g·m-3,the removal rate is 70%,75%and 90%,the removal loads were 31,22 and 14 g·m-3h-1.（3）According to the gas-liquid-biofilm three-phase steady-state kinetic model,the performance prediction under different circulating fluid,residence time,and intake gas concentration shows that when the purification rate of chlorobenzene reaches the inflection point,the height of the BTF packing layer increases with the increase of the circulating fluid flow rate.Large;the export chlorobenzene concentration decreases with the increase of EBRT;the export chlorobenzene removal efficiency decreases with the increase of the import chlorobenzene concentration,and the removal load increases with the increase of the import concentration.Experimental simulation verification shows that when the intake air concentration is 1g·m-3and EBRT=60s,the BTF has a maximum EC of 36 g·m-3h-1,and the maximum EC predicted by the model is 37 g·m-3h-1,And the relative average error of the removal rate prediction during the stable period is 5.88%.（4）When the amount of rhamnolipid added is 1CMC,the intake concentration is 1 g·m-3,and EBRT=60s,the removal efficiency and removal load of chlorobenzene reach the maximum,which are 81%and 49 g·m-3h,respectively.1.Compared with the addition of no rhamnolipid,it is increased by 24%,and the effect of strengthening BTF is the most significant.（5）When the concentration of rhamnolipid was 1.25CMC and the height of the filler layer was 5cm,the protein and polysaccharide content reached the highest,which were 50.19 mg/g VSS and 62.52mg/g VSS respectively;the Zeta potential of EPS dropped from-20.37 m V to-13.13m V;The relative hydrophobicity of biofilms increased from 30%to 65%.Under the action of rhamnolipids,the growth of biomass was stimulated,and both protein and polysaccharides showed an increasing trend;the relative hydrophobicity of the surface of the biofilm increased,the mass transfer resistance decreased,and the gas-liquid mass transfer rate increased;The negativeness is gradually reduced,making it easier for microorganisms to gather and adhere to the filler,and the biofilm is more dense and stable,which enhances the performance of the biofilm and the purification effect of BTF.There were 25 figures,14 tables,and 146 references in this paper. |
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