| With the development of the society, more and more waste water is been discharged, on the other hand, due to the increased public awareness of the problem of water pollution, effluent standards for wastewater treatment plants (WWTP) are becoming more and more stringent. In order to obtain the balance between economic and social benefit, advanced control strategies must be applied to wastewater treatment processes. Biological wastewater treatment processes, where organic materials in wastewater are removed microorganism, are widely used as secondary treatment processes, which are of nonlinear, uncertain, time-varying and delay-time complex systemsin terms of control theory. So we must use mathematical models and computer simulations to look into the processes and realize the optimal design and control for activated sludge processes. Compared with international level, most similar development and applications of the activated sludge models in China is backward, even the effective simulation and controlling platform is still lacked, which is lower universality. Before the simulation of the activated sludge processes, a reliable software platform must be developed first. In order to promote the use of activated sludge model in our country, ASSSC (Activated Sludge System Simulation and Controlling), a simulator of the activated sludge processes based on Visual C++6.0 and Matlab, is presented through the object-oriented modeling technology. With the "modularization" ideal, the models of aeration cell, anaerobic cell and anoxic cell are built separately, and different activated sludge system can be formed with activated sludge models in the client area of the software, which has good universality. The standard library for the structures and the classical processes of the WWTP are included, for the users to set-up the real wastewater treatment process conveniently. And ASSSC is based on our FCASM3 (Full Coupled Activated Sludge Model), which is applicable to Chinese situation and can achieve the goal of real-time automatic control and optimal operation system in WWTP.The ASSSC software was used for the simulation of water temperature effects on the response pattern of enhanced biological phosphorus removal (EBPR) system, to finish the calibration in labscale. The results about physical and numerical simulation of the recovery of the collapsed EBPR system destroyed by rising temperature were investigated based on ASSSC simulation under different temperatures(20℃,25℃,30℃,35℃), respectively. The parallel running of water temperature in 25℃and 30℃showed that the phosphorus removal rate of EBPR was decreased with the temperature increasing. Meanwhile, treatment efficiency of the EBPR system at 35℃could not be recovered to its original state in the short term in the short term. Which means that we must keep the running water temperature under 30℃, and avoid the temperature above 35℃, in order to reach the phosphorus removal rate of EBPR above 80%. The results show that ASSSC can be used to simulate and optimize the performance of activated sludge treatment system and avoid the unknown damage.The ASSSC simulation results of AAO and new-style oxidation ditch process in the WWTP finished its full-scale caliberation. The dynamic simulation showed that ASSSC could be used to simulate the process of nitrogen, simplify the parameters adjustment and speed up the mathetical models in guiding WWTP. phosphorus removal and article confirmeed the accuracy and reliability of the model application procedure, and discussed the influence of model parameter change to the water leakage target analogue result. The article also studied the model parameter value that had suited the test, which had the more reliable theory basis for experimental operational management. The simulation results correlated well the measured values. In addition, the procedure was used to analyse the affection of the plant's operating and controling on the parameters of the effluent water qulity, and the actuality was accorded by the predicted results.Application studies were accomplished by caliberated ASSSC for an automatic control and monitor system with sequencing batch reactor activated sludge process (SBR). The development of negative feedback control interface with three parameters:DO, temperature and pH were included in ASSSC. The simulation and controlling syudies based on FCASM3 were completed at SBR process EBPR system for about a month. The dynamic simulation results indicated that this system could reasonably and automatically adjust aeration rate, temperature and pH to realize the negative feedback control of those three parameters. Meanwhile, it could use internal models to simulate the real process for the application of this system, and practically promote process operation efficiency and reduce running cost on the premise of guaranteeing discharge water quality. Hence, ASSSC layed a foundation for real time negative feedback control and optimal operation system in WWTP.
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