Experimental And Simulation Study Of Oxygen Transfer Process Combining ASM2D Model

Wastewater treatment is an important part to solve the problem of water pollution,but at present,most of the wastewater treatment plants(WWTP)have the problem of running energy consumption and processing cost,the main reason is the inefficient and high consumption of the aeration system,which is the main energy dissipation unit of the WWTP.Under the background of "Energy saving and emission reduction",the research on the system of the main energy dissipation unit-aeration system in the sewage treatment plant is helpful to realize the energy saving and consumption reduction of the WWTP,and it is very important to improve the efficiency of wastewater treatment and reduce the operation cost.In this study,the aeration system of a typical sewage treatment plant was used as the research object,firstly,the influencing factors of oxygen transfer in microporous aeration equipment were studied,and the factors influencing the oxygen-carrying capacity of the microporous aerator were analyzed.In addition,the experiment and simulation of aeration oxygen transfer process based on ASM2D model were carried out,Part of the experimental research in the ASM2D model for the division of COD components,analysis of the changes in COD components of the oxygen transfer process,the simulation of the study is the establishment of the actual wastewater treatment plant mathematical model,and on this basis through aeration control to achieve energy saving targets.The main conclusions of the study are as follows:(1).Experimental study on the influence factors of oxygen transfer process in micro-porous aerator:1)when the aeration volume changes in the 0.5?2m3/h range,the standard oxygen transfer coefficient KLa(20)and the standard oxygen transfer rate SOTR of the micro-porous aerator increase with the increase of aeration volume;2).The presence of salinity in water has a certain effect on the oxygen transfer rate of microporous aerator.In the scope of the study,the oxygen transfer rate of microporous aerator is less affected when the salinity of water changes in 0?1500mg/L range.When the salinity of the water exceeds 1500mg/L,the oxygen transfer rate of the microporous aerator increases with the increase of salinity in the water;3).with surfactant SDBS content in 0?20mg/L range,the value of the standard oxygen transfer coefficient KLa(20)is generally reduced,the value of a factor is the lowest of 0.97,which shows the advantage of the microporous aerator;4).when the water temperature changes in the 13.5±0.5??29.1 ±0.5? range,as the water temperature increases,The oxygen transfer rate of aeration equipment will increase.Analysis of the effect of temperature on oxygen transfer under different aeration,this paper has determined that the correction of the oxygen transfer coefficient in the experimental test water quality is in the range of 1.036?1.049;5).Two common types of fillers(three-dimensional hollow ball and multi-surface hollow ball filler)are studied,when the filling rate of filler is changed in the 0%?50%range,With the increase of filling rate,the overall trend of oxygen transfer coefficient and oxygen transfer capacity of aeration equipment is increased.In particular,the increase in the case of 0%?37.50%is obvious,but when the change is not very obvious;6).with the increase of cod value in sewage,the oxygen transfer efficiency and other oxygen transfer evaluation indexes are decreased,that is,the oxygen transfer ability is inhibited by cod,? factor is between 0.782?0.962.(2)Combining the components of COD in the ASM2D model,the effect of different component changes on the oxygen transfer coefficient was studied by the method of artificial sewage disposal,and for the component SA,SF,Si and Xi,the value of KLa(20)decreased with the increasing of the concentration of components.For the component Xs,the value of KLa(20)is basically unchanged and the alpha factor value is 0.931 as the concentration of the component increases.as the concentration of the component increased.In the range of the influence of each component,the descending range of KLa(20)value is from big to small in order:XI+SI,SF,SA,Xs,and the influence fitting formula of each COD component on KLa(20)value is established.(3)Based on the ASM2D model,the model of a sewage treatment plant in XI ' an was established by using the simulation software WEST of the WWTP,and the related research on the aeration control process was carried out.Comprehensive theoretical simulation conclusion and practical experience,in the control of aerobic pool do,it can be controlled in 1.5?2mg/L to achieve the dual purposes of water quality and aeration energy saving.Through cascade control strategy to control the do concentration of aeration pool according to the effluent NH3-N concentration,the control strategy makes the control of the do concentration of the aeration pool more fitting to the actual demand.The simulation results show that the average daily aeration energy consumption of the aerobic tank in a sewage plant can be reduced by about 6.6%after using cascade control strategy.