Research On Urban Sewage Treatment Process And Prediction Model Based On SAnMBR

Since the 90s of last century,energy intensive technologies have been used in urban sewage treatment in China.At present,more and more mature treatment technology has been widely used in urban sewage treatment.Most of these technologies are aerobic biological treatment technology,the treatment effect is good,and the operation is stable.However,the conventional aerobic biological treatment technology has many problems,such as high energy consumption,and can not recover energy from sewage.Therefore,seeking more efficient,low cost and energy saving urban sewage treatment process is the focus of everyone's attention.The submerged anaerobic membrane bioreactor?Submerged anaerobic membrane bioreactor,SAnMBR?is a new wastewater treatment process which combines the anaerobic biological technology with the membrane bioreactor efficiently.It not only has the advantages of low energy consumption and energy gas,but also has the advantages of good water quality and small area in the membrane bioreactor,and has a certain potential in the treatment of urban sewage.Therefore,this technology has attracted wide attention from scholars at home and abroad.At present,the research and application of SAnMBR technology in the treatment of high concentration organic wastewater is more.However,the research on the application of SAnMBR technology to the start-up and stable operation characteristics of low concentration urban sewage treatment is insufficient,and the related membrane fouling mechanism is not clear.Based on the above problems,this paper takes the simulated urban sewage as the object.Through the construction of the small scale SAnMBR,this paper studies the quick start and stable running characteristics of the reactor,and optimizes the process parameters by changing the water quality,HRT,OLR and other technological conditions.A SAnMBR support vector machine model for urban sewage treatment was established,and the model was used to simulate and predict reactor operation and membrane fouling.The start-up and stable operation characteristics of SAnMBR show that SAnMBR can start at 28d at medium temperature.Under the condition of HRT 6¹5h and influent OLR 0.87².60kg COD·m^-3·d^-1,SAnMBR can maintain stable operation.The removal rate of COD is stable at the stage of stable operation,and the removal of COD above 80%COD is dominated by biochemical degradation of anaerobic cell microorganism,and CH₄ average daily yield is higher than that of 760mL/d.The VFAs concentration of oxygen unit and the amount of CH₄produced were significantly correlated with OLR.Among them,the relationship between CH₄production and OLR is as follows:CH₄=0.18×OLR+0.37.Based on the operation data of SAnMBR,through the grid parameter optimization algorithm and cross validation,the best gamma function value is 0.278,and the penalty factor C factor is 1.250.The 12 LibSVM models are compared to determine the LibSVM model suitable for SAnMBR,which is the Lib₁1 model?epsilon-SVR-RBF model?.The model is more advantageous under the condition of SAnMBR multiple factors.The study of membrane fouling characteristics of SAnMBR showed that after SAnMBR treatment,EPS,protein and polysaccharide were all accumulated on the membrane surface,but after the anaerobic cell biodegradation and membrane cell filtration interception,the protein concentration was reduced,the species had no obvious change,and the protein was more likely to cause membrane pollution than the polysaccharide..A SVM membrane fouling model with TMP and total membrane resistance as the test value?model output value?was established.When the concentration of EPS is higher than300mg/L,the total membrane resistance appears and TMP does not appear.The correlation between sludge viscosity and TMP is more significant than that of the total membrane resistance.