Development And Application Of Intelligent Control Strategy For Sbr Based On Fcasm4Mechanism Model

In China, with the social and economic development, environmental issues become increasingly prominent. In order to ease the pressure on the environment, all kinds of pollutants emission standards are becoming increasingly stringent. The improved standard of the "urban sewage treatment plant pollutants discharge standards" faced with the problem of the transformation the plant to meet the standard. SBR process is widely used in mid-small city sewage treatment plant because of having a small footprint, high degree of automation and easy operation and management. The effect of SBR process is depended on the operation of the SBR process. Control strategy is the core of the entire process. Then the control strategy is considered to be the soul of SBR technology. Intelligent control strategy as the senior development situation of SBR process is generally concerned. With the development of ICA technology, intelligent control technology based on mechanistic model has gradually matured and has a broad prospect.By control the operating sequence of SBR process, it could achieve simultaneous nitrogen and phosphorus removal in one reactor. But the existing technology has a poor simultaneous nitrogen and phosphorus removal efficiency. In this paper, Comparative pilot study is conducted with different stages of the influent, different influent ways and different aeration ways of SBR process under the fluctuated water quality to choose the optimal simultaneously nitrogen and phosphorus removal SBR process. Influent in aerobic phase, although ammonia removal system more stable, its phosphate removal is not ideal and can’t meet the emission standard limits. Influent in anaerobic phase, the denitrification capacity is constrained, but the system is more stable in phosphate removal and ammonia removal efficiency is also well. Step feed of SBR process will not only help to improve the nitrogen removal efficiency, but also promote the removal of phosphate and utilize of organic matter more fully. And the variation coefficient analysis of the test results were show that step feed reactor not only the nitrogen and phosphorus removal rate higher than the effect of one-off water reactor, but also the treatment effect is more stable. Intermittent aeration system is favor of upgrade the denitrification ability, but because lack of carbon source in the influent, making the phosphorus removal efficiency is affected, but the average phosphate removal rate still above95%. With simultaneous nitrogen and phosphorus as the election principles and combined with the variation analysis of pollutant removal rate, the combination of intermittent aeration and step feed SBR operation mode can achieve well nitrogen and phosphorus removal efficiency.Fully coupled activated sludge model (FCASM4) is used to establish the SBR coupled model. Then the model of the selected optimal SBR process is developed. Through MATLAB software, numerical model of SBR process is programmed. Sensitivity analysis is used to adjust the kinetic parameters of FCASM4. With66d’test data, the SBR process model is calibrated and validated. The verification results show that the SBR process model based on FCASM4can be simulated a good organic matter, nitrogen and phosphorus removal process, and the error analysis results are within10%. To further tap the nitrogen and phosphorus removal capacity, the mathematical model established is used to simulate the optimum operating conditions for the selected SBR process. Through the analysis of variance of the simulation results, screening out the best solution of oxygen, sludge age and drainage ratio. Static numerical simulation results obtained the optimal dissolved oxygen, sludge age and drainage ratios are4mg/L,10d and1/3, respectively.In this paper, an intelligent SBR control strategy is developed based on FCASM4mechanistic model. And at the same time, intelligent SBR control software is developed with LabVIEW. Through mixed programming between LabVIEW and MATLAB, the intelligent control strategy based on FCASM4mechanism model is achieved. The effect of intelligent SBR control strategy is verified under the test with fluctuated influent water quality. By setting three experimental groups, comparison is among the intelligent control strategy controlled reactor, conventional denitrification reactor and the model simulated optimal values as the control parameter test. Experimental results show that the intelligent control strategy controlled reactor not only the organic matter nitrogen and phosphorus removal efficiency better than the other two test, but also the removal stability is better than the other two test. Especially, the removal efficiency of nitrogen is higher than the other two experimental groups25.11%and7.9%respectively. All of these indicate that the intelligent control strategy controlled SBR reactor is superior to other control methods.