Modeling And Parameter Optimization Analysis Of Cyclic Activated Sludge System(CASS) Model Based On ASM3

With the growing emphasis puted on the environmental issues, China continued to increase the investment in environmental infrastructure. The penetration of the wastewater treatment plant improved significantly. However, most of these plants are dispersedly managed, lack of scientific diagnostic system and without necessary real-time monitoring and analysis techniques when face the impact of water quality. The water plants along Song Hua River in Harbin is facing a series of problems such as the water quality standards which may increased at any time, the lack of cluster management software platform and the low C/N wastewater due to the change of lifestyle. Therefore, in order to solve these problems, this article built the new E-ASM3 model based on ASM3 which can quickly and accurately predict and analyze pollutant reductions for CASS process. And then, find the optimal reduction operating point of pollutant when dell with low C/N wastewater by CASS process with E-ASM3 model and orthogonal experiment together. A brief analysis of energy-saving and emission reduction at last.Based on the ASM3 model, this article introduces the concept of SMP and EPS, adding new components SSMP(including SUAP and SBAP), XEPS, new SSMP reaction process of storage, etc.; In the kinetic expressions, in accordance with the theory of “simultaneous substrate storage and growth”, the f STO parameter is introduced to control the proportion of matrix which is used to storage, and the + switch function is introduced to reflect the timing when matrix enter the shortage period. in accordance with the theory of “simultaneous substrate storage and growth”; Establish the material balance equation with two stages in view of the CASS process. Built the new E-ASM3 model, and the visual simulation program with the modular tools of MATLAB/Simulink.After the sensitivity analysis, the parameters which have great influence on water quality, such as YSTO.O, b H.O, YSTO.H.O, b A.O, μA, YA, k BAP.O, k H.EPS, f EPS.STO have been adjusted, to make the average error is 0.57% when doing steady simulation of the test in laboratory device. After considering the temperature correction, the average error was 7.4%, 29.05% and 11.02% when doing steady simulation of COD, NH3-N and TN in the effluent, to remove some discrete values, the basic trend of simulation value, to remove the discrete values, is conformed to the effluent.Through the model simulation of four process parameters of CASS process in the treatment of low C/N wastewater. The results showed that the removal rate of COD and NH3-N decrease with the increase of the water filling ratio; the aeration time longer than 3 h has a little effects on the effluent quality; the sludge reflux ratio impact the removal rate of NH3-N greatly; and concentration of SMP related to the trend of COD, while EPS is opposite.Analysis results by orthogonal test shows that the water filling ratio λ=0.25 is always the optimal conditions facing wastewater in different C/N and different effluent indexs; Aeration time 3 h(after 1h) is the optimal condition which can not only make sure of good effluent quality but also economic than 4h. We can get the optimal removal rate of COD by 50% sludge reflux ratio and 5:30 reaction zone proportion, but 100% sludge reflux ratio and 7:28 reaction zone proportion get a better effect on othe effluent indexs. Combined with the comprehensive energy consumption analysis and law of simulation,I ultimately determine water filling ratio of 0.25, the aeration time of 3 h(after 1 h), the sludge reflux ratio of 75%, the reaction zone proportion of 1:7:28 is the optimal reduction operating point, and put forward targeted optimization suggestions.