Study On Pretreatment Technology Of Pharmaceutical Wastewater By Heterogeneous Catalytic Ozonation

Pharmaceutical wastewater has high organic content,contains more cyclic aromatic hydrocarbons,and has poor biochemical properties.If it is treated by physicochemical-biochemical treatment,there are still a lot of organic pollutants remaining,and if it is discharged into the water body,it will have a negative impact on the environment.Therefore,improving biochemical properties is a prerequisite for the treatment of pharmaceutical wastewater.Based on the ozone oxidation method,this study aims to improve the biochemical properties of pharmaceutical wastewater.By adding different kinds of catalysts,the ozone oxidation method is further optimized to improve the treatment effect and provide new ideas for the treatment of pharmaceutical wastewater.The specific research contents are as follows:Treatment of pharmaceutical wastewater by ozone oxidation and catalytic ozone oxidation:The influence of factors such as ozone intake amount,contact time,temperature and p H on the treatment effect in the ozone oxidation method was investigated by using the controlled variable method.The treatment effect is better under the conditions of ozone intake rate of 800m L/min,temperature of 25℃,and p H=8.Then,by adding different catalysts Mn O-Al₂O₃and H₂O₂,the effects of catalyst dosage,contact time,temperature and p H on COD removal rate,ammonia nitrogen removal rate,BOD concentration and BOD concentration/COD concentration（B/C）of pharmaceutical wastewater were investigated.Influence.Combination of catalysts for ozonation treatment of pharmaceutical wastewater:Mn O-Al₂O₃and H₂O₂were used in combination to investigate the effects of different catalyst dosage,temperature,p H and other factors on the treatment effect.Under the conditions of Mn O-Al₂O₃dosage of 150g/L,temperature of 25℃and p H=8,the COD removal rate can reach 70%and B/C is 0.370.Standards for Biochemical Wastewater.The response surface experiment was carried out on three factors of Mn O-Al₂O₃dosage,H₂O₂dosage and p H.The results showed that the selected model could be used for prediction,and the three factors had significant influence on the treatment effect.Comparative analysis,kinetic analysis,economic analysis and mechanism analysis of the effects of each process:for the ozone oxidation method,the Mn O-Al₂O₃catalytic ozone oxidation method,the H₂O₂catalytic ozone oxidation method,and the Mn O-Al₂O₃and H₂O₂combined catalytic oxidation method.The comparative analysis of the treatment effect shows that the combined use of catalysts has the best effect on the treatment of pharmaceutical wastewater.And the kinetic analysis shows that the reaction process of COD degradation in each oxidation process conforms to the first-order kinetic equation.The cost of COD degradation by four processes was analyzed,and it was concluded that the combination of Mn O-Al₂O₃and H₂O₂had the best treatment effect,low cost and economic applicability,indicating that the heterogeneous catalytic ozonation process is sui Tablefor practical pharmaceutical wastewater.processing.The mechanism of each process was analyzed and studied.The mechanism of ozone generation·OH was divided into two parts:intermediate radical and intermediate electron transfer.The Mn O-Al₂O₃catalytic mechanism was the intermediate radical mechanism,and the H₂O₂catalytic mechanism was the intermediate electron transfer mechanism.Based on the ozone oxidation method,this study aims to improve the biochemical properties of wastewater by optimizing catalysts,in order to provide theoretical and technical support for the biochemical treatment of refractory biodegradable wastewater.