Discussion On The Determination Method Of Wastewater Biodegradability By Using Biochemical Microreacter And Research On Mathematical Modeling Of SBR Process

The biodegradability of wastewater is an important parameter for process optimization in a wastewater biochemical system,and the B/C method often dilutes the wastewater by a large multiple during the determination process,and deviations often occur in practical engineering applications.Therefore,looking for a The evaluation method of wastewater biodegradability with high simulation degree in actual biochemical system is of great significance.In this dissertation,a device that simulates an actual biochemical treatment tank and a biochemical microreactor are used as a research platform.The actual pharmaceutical wastewater is used as the research object,and the biochemical respiration curve of microorganisms is used as the research basis.A new method for detecting biodegradability of wastewater is proposed.And the measured index is defined as the biochemical respiration index(Ks),and the index is applied to the optimization study of the SBR process.The research results are as follows:1?It was resulted that the COD removal rate corresponds to the Ks value of wastewater in the condition of the same HRT.The special strain had a marked effect on the improvement of wastewater Ks value,so that the same wastewater also has different Ks in different biochemical systems.With the increase of SS concentration in biochemical system,The Ks index of wastewater is also gradually increasing.2?Compared with the commonly used B/C value,the Ks value proposed in this paper can not only reflect the biodegradability of wastewater in the actual biochemical system,but also reflect the biodegradability of wastewater.With reference to the COD volume load index in the actual biochemical system,we find that when the COD volume load is 0.2 Kg/(m3·d),the biochemical respiration index Ks is 5.0.Therefore,Ks=5.0 is used as the critical value to evaluate the biodegradability of wastewater.When Ks<5.0,it indicates that the biodegradability of this wastewater is poor.When Ks?5.0,it indicates that the biodegradability of this wastewater is better,and the larger the value,the higher the biodegradability.3?Through the study of various parameters in the SBR biochemical process,it was found that the Ks index is mainly related to the time distribution of anoxic and aerobic sections,dissolved oxygen,influent COD,SS:(1)In the SBR biochemical process,the Ks index generally decreases first and then increases at various times,which is the reason why microorganisms perform different decomposition in different dissolved oxygen environments.(2)Taking the SBR process with HRT=6 h as an example,the optimization results of the Ks index show that the optimal process conditions are: HRT=2 h in the anoxic section,HRT=4 h in the aerobic section,and 4 mg/L-6 mg/L of dissolved oxygen in the aerobic section,the COD concentration of the incoming water is 8000 mg/L,and the SS is 8800 mg/L,the COD volume load can reach 1.6 Kg/(m3·d).4?Based on a large amount of data,a mathematical model of the SBR process based on the RBF artificial neural network is established in this paper.Simulation experiments show that when the number of training steps of the neural network is 17785,the sample training is successful.At this time,R2 is 0.98124,indicating that the model fitting effect is relatively good.Good;the average relative error between the predicted value and the true value is about5%,indicating that the model can accurately predict the COD volume load of the SBR biochemical process and the sum of Ks in each period,thereby achieving optimization of the SBR biochemical process.