| Once the quantity of microorganism in the discharge water of natural water body discharged after municipal sewage treatment is not up to the standard,it will not only damage the ecological environment to a certain extent,but also pose a certain degree of hidden threat to human health.Therefore,it is more and more important to choose an economical,safe and effective sterilization method.The research object is a sewage treatment plant in Harbin hulan district ultraviolet sterilization system,the early the CASS process of wastewater plant effluent water quality situation and cause excess ultraviolet sterilization system effluent fecal escherichia coli research,designed with ultraviolet disinfection system for wastewater plant in accordance with the actual continuous ultraviolet sterilization reaction device and a CFD simulation optimization was carried out.After the study of ultraviolet sterilization process,the influence factors on the effluent fecal coliform bacteria inactivated regularity of resurrection and fecal coliform bacteria after ultraviolet germicidal light phenomenon,find the optimum process parameters and process conditions,put forward the energy saving,time saving,strong operability of the sterilization process,thus ensuring water ultraviolet sterilization system can run effectively.The ultraviolet sterilization system of sewage plant was investigated,and the ultraviolet sterilization reactor was designed and optimized.The results showed that when the inlet flow rate was 0.91 m~3/s,the number of lamps was insufficient,the ultraviolet dose was not enough,and the sterilization effect was not up to standard.COD of inlet water changes greatly compared with other inlet water indexes(SS,chroma,ammonia nitrogen,etc.),and the fluctuation of inlet water quality will directly affect the sterilization effect of ultraviolet sterilization system.According to the design parameters and the determination of ultraviolet dose,the ultraviolet bactericidal reactor was designed with reference to the ultraviolet bactericidal system in actual engineering.CFD was used to optimize the design of the reactor,and the ultraviolet bactericidal reactor after adding baffles could effectively improve the hydraulic conditions of the water flow in the reactor and improve the bactericidal efficiency.The uv sterilization process with different wavelengths,the combined sterilization process with uv and chemical agents affected by inlet water quality,and the law of light resurrection of effluent fecal coliforms,were studied.Ultraviolet and hypochlorous acid combined sterilization has a certain synergistic effect,and can achieve a very good sterilization effect at a lower combination dose.When the hydraulic retention time is 30s,the dosage of hypochlorous acid is 1mg/L,and the contact time is 2min,the logarithmic inactivation rate can reach 5.Response surface optimization method was used to optimize the combined sterilization process parameters of ultraviolet and hypochlorous acid,and the results showed that:Under the optimal technological conditions,the irradiation time of ultraviolet lamp is 30s,the effective chlorine concentration of hypochlorous acid is 2mg/L,and the contact time of hypochlorous acid and water sample is 6min.Under this technological condition,the logarithmic inactivation rate of effluent fecal coliform group can reach 5.60.In conclusion,replacing the new ultraviolet lamp(UV185)or adding a certain amount of chemical agents on the basis of the original ultraviolet sterilization process can improve the sterilization effect and effectively control the phenomenon of excess water. |
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