Research On Application Of Simulation Software In AAO,CAST And MBR WWTP

Domestic and foreign sewage treatment methods are mainly activated sludge method.The establishment of a sewage sludge model based on the activated sludge model can achieve the purpose of optimizing the operating parameters of the sewage treatment plant,saving energy and reducing the risk of upgrading the sewage plant.WEST software has a friendly man-machine interface and easy to operate,so choose WEST software to build sewage plant model.MBR,A~2/O and CAST process types are widely used in China.Therefore,the application of simulation software WEST in MBR sewage plant,A~2/O sewage plant and CAST sewage plant can be used to popularize the application of simulation software in sewage treatment plant.According to the paper on the application of WEST in three processes,the following conclusions are drawn:(1)The WEST modeling steps include the establishment of a basic process model at the layout interface,the decomposition of the influent data into the input water and the steady state and dynamic simulation and model correction.WEST’s advanced features to help determine the parameters for optimization and tagging transformation program to determine.(2)The MBR wastewater treatment plant model was established by using WEST simulation software and the corrected model could simulate the MBR process well.In order to solve the problem of insufficient carbon source in the WWTP,three factor 3 levels of orthogonal test were designed by using Design-Expert software.The results of orthogonal test showed that the effect of DO,internal reflux flow and external reflux flow on the total nitrogen value of effluent was not significant.The results show that the optimization of the operating parameters can not reduce the total nitrogen content of the effluent below the A-level limit,and the main reason for the non-compliance of the total nitrogen is that the carbon source is insufficient.Using the model to do the carbon source dosing test,when the dosage is 20mgCOD/L,the total nitrogen content of the water is as low as 11.16mg/L,and the 30-day compliance rate is 100%.(3)Using the WEST simulation software to build the CAST sewage treatment plant model,the timer and the input tool are used to control the timing opening and closing of the inlet valve.The simulated water quality index of the model is in good agreement with the measured value.The models established in spring and outbound water data simulate the effluent quality in summer and winter,and the simulated water quality index values and the measured values are very different.Therefore,each model trial period is only the season,and the respective models need to be established in each season.Taking the spring model as an example,the design experiment was designed by using Design-Expert software to optimize the running parameters.After optimization,the total nitrogen content could reach Grade B and the total phosphorus could not reach the standard.In the reaction period of CAST,the low exposure time was added and the 4 factor 3 level test was designed to find out that the optimal combination of low exposure time was 80m3/d,5000m3/h,low exposure time 0.6h,Strength of 0m3/h,the water of the indicators can reach a B standard.(4)A~2/O process of sewage plants exist in the total phosphorus is not up to a B standard(<1mg/L)problem.Using the WEST simulation software to build the A~2/O sewage plant model,and to correct the model,the corrected model can be a good model for the actual sewage plant to run.The internal reflow,external reflux and aeration were taken as experimental factors,and the water quality index was the objective function,and then the two parameters were estimated.The parameter estimation experiment determines the optimal combination,and the optimized effluent quality can reach Grade B.For the optimization of energy consumption analysis,comprehensive selection of the best solution is aeration of 5000m3/h,the internal return of 30000m3/d,the external return is 50m3/d.For the water quality to reach a level A standard.Using the WEST software,the design of the addition of phosphorus removal agent to determine the sewage plant phosphorus removal agent dosage,the results show that the dosage is 5m3/d,the effluent compliance rate rose to 100%.So the phosphorus removal agent is set at 5m3/d(Fe:P=4.8).(5)A~2/O,MBR and CAST process technology and operation are not the same,so there are different modeling methods.A~2/O uses three Activated Sludge units.MBR can be composed of three Activated Sludge Unit and membrane pool combination,membrane pool both filtration process and biochemical process,belonging to biochemical MBR simulation.The CAST process is approximately treated and consists of a Activated Sludge Unit and four SBR pools.A~2/O process does not need to control the time,the simulation speed is faster,so the operation parameter optimization selects the parameter estimation experiment or the plan analysis experiment.MBR and CAST processes require control of time and slow simulation,so parameter optimization is done using orthogonal test methods to reduce the number of trials and save the total time.In the WEST application,the addition of anti-phosphorus test,carbon source dosing test,change the mode of operation,calculate the operating costs can be used in A~2/O,MBR,CAST process.A~2/O and MBR applications focus on obtaining general,inverted,improved operation of the simulation results.The CAST application focuses on the change and division of the operating cycle.Pond changes are only available for A~2/O-type processes.