Application Research On Simplifying Model Of Chao Yang Wastewater Treatment Plant's Biochemical Process Based On The ASM2D

The deep well aeration process adopted by the Chaoyang Water Purification Plant in Harbin City is located in the cold regions of northern China.Therefore,the influent water quality is greatly affected by the temperature and the influent conditions.In order to effectively manage the daily operation of the water plant,modeling and analyzing the changes of the deep well aeration process water quality is required.The conventional process modeling methods for wastewater treatment are generally activated sludge series models(ASMs)and their modified and simplified models.However,the modeling and analysis of deep well aeration processes in cold regions has not related report.Therefore,In this study,by selecting the key mechanism of the activated sludge 2D model(ASM2D model),simplifying the simulation of the water quality equations,and estimating the dissolved oxygen concentration in the deep well aeration tank,a water quality simulation model suitable for the deep well aeration process was established and testing platform for theoretical model was established to test the reliability of the model and identify sensitive parameters in the model,performing application analysis and verification,as well as providing effective support for the operation and control of the promotion and management of deep well aeration processes in northern cold regions.For the actual zoning of the deep well aeration process,the biochemical reaction processes occurring in the anoxic zone,anaerobic zone,deep well aeration zone,and clarification zone are used as the main research objects of the ASM2 D model,with the aerobic nitrification process,the anoxic denitrification process,the anaerobic phosphorus release process of phosphate-accumulating bacteria,the aerobic phosphorus absorption process of phosphorus-accumulating bacteria,and the denitrifying phosphorus-absorbing process of phosphorus accumulating bacteria are the main processes.The core reactions and key variables of the process of nitrogen and phosphorus removal in the ASM2 D model are preserved,Linearizing the Monod item of some variables,according to the setting of the reaction zone of the deep well aeration process and the sewage treatment process,simplifing the expression of the process rate of the ASM2 D model,establishing the water quality simulation model applicable to the deep well aeration process whose structure can be identified,obtaining 19 reactions equations and the differential nonlinear equations of the 17-term kinetic parameters.After two consecutive years of on-site experiments in spring and winter in Chaoyang Water Purification Plant in Harbin City,inspecting the two cases of adding and not adding phosphorus removal medicine,the data of water quality and quantity in each reaction zone of the secondary treatment process were analyzed and used.Using the 2016 winter and 2017 spring at normal temperature and low temperature in the stable operation period individually to estimate model parameter values,the water quality data of each season was used to estimate the parameter values of the differential equations in the simulation model using the simple algorithm on the Matlab platform.The results showed that the different water inlet conditions and the effects of adding phosphorus removal medicine at different period,make the estimation results of most of the parameters in the ammonia nitrogen and nitrate reaction equations are relatively close,but the fluctuation range of some parameter estimation results in the phosphate reaction equation is relatively large.The validity and reliability of the simulation model were studied,and a theoretical model test platform was built based on Simulink software.Using the water quality data during the stable operation period in the same period in 2017 winter and 2018 spring,the water quality of different water components in each reaction area was simulated to analyze the accuracy of the fitting effect between the predicted and actual values of different components.The results show that the simulation model has a good prediction effect.Each parameter individually changes ±5% and ±10%,testing the sensitivity of the model parameters to identify sensitive parameters changes in pollutant concentration.The research results were applied to the water purification plant in the Chaoyang Water Purification Plant in Harbin City,which can predict the effluent water quality under different influent conditions,provide recommended operating parameters for the daily operation of the water plant,guide its production and operation,and enable the water plant to meet the water standards,save energy and reduce consumption.The research results have good social,environmental and economic benefits.