The Quantitative Evaluation Of Activated Sludge Processing Capacity

Activated sludge method has become the most widely used in sewage treatment method because of its stability and high efficiency in the process of sewage treatment.At present,although there are many wastewater treatment plants?WWTPs?in China are using activated sludge method,but due to the existence of complex water quality,low processing capacity,low load operation and other issues,resulting in the actual treatment results are not satisfactory.With the increasingly strict standards of sewage discharge,improve the operation and management of WWTPs to ensure that the sewage plant can be stable operation,efficient treatment,so that the water quality can reach the national emission standards,is one of the more important core issues in the water treatment.At present,there are some sewage plants at home and abroad for the use of empirical methods or a variety of sludge models to simulate the actual situation to assist the operation and management so that improve the water quality.However,due to the dynamic process of the activated sludge sewage treatment is very complex,when subject to external interference,its modeling and accurate simulation will be more difficult.Therefore,there is two facors which it is necessary when predict and control of the process must take into account the environment of the external and the sludge itself,although in the activated sludge series model?ASM?there are many key parameters can express these two factors,but in fact some of these parameters must require complex measurement processes can be obtained and due to the state of the activated sludge is constantly changing in actual,the common model is not effective in assisting the actual operation and management of the WWTP and must be improved or combined with other method to optimize the operation effect of WWTP.In this study,According to the managers and operators of WWTPs were able to know the sludge treatment capacity and the effluent quality problem in time.Based on the activated sludge model 1?ASM1?and the breathing measurement method,and tried to find a simple and quick method which can learn the actual sewage treatment plant activated sludge system processing capacity and water quality,so as to assist the operation and management of sewage plants and provide the scientific basis.The contents and results of the study mainly include the following aspects:?1?The activated sludge model 1?ASM1?was analyzed and according to the mechanism and reaction process of microorganism with sewage established the simplified sludge model.The necessary process of sewage and sludge was described in brief way.To provide a theoretical basis for the following described Respirograms.?2?The Respirograms is proposed,include the sludge respirogram and the inffluent respirogram.Based on the measurement and theoretical calculation of the sludge respirogram,it is concluded that the three parameters R_db,R_cb and R_st in the sludge respirogram are used to predict the effluent of the WWTP whether be able to reached the discharge standard: when R_st <R_db,the capacity of the activated sludge system is good and the sewage treatment plant effluent can meet the discharge standards;when R_st> R_cb,the capacity of the activated sludge system is poor and the sewage treatment plant effluent will exceed the discharge standards;and when R_cb <R_st <R_db,the sewage treatment plant effluent may be reached the discharge standard,or one of the COD and ammonia nitrogen in the effluent will be exceed the discharge standards.?3?The other two parameters,Rect and Rent,in the sludge respirogram were analyzed and found that these two parameters can show the environmental status?mainly temperature and biomass ratio?of activated sludge.Accordingly,the R_db and R_cb values of corresponding operating conditions can be obtained.?4?Due to the limitations of the sludge respirogram,this study also analyzed the inffluent respirogram and obtained the fitting HRT value t_FH by fitting the OUR curve of the inffluent respirogram,which is obtained during the fitting process which the last of X_S and ammonia nitrogen are degraded to the HRT below the emission standard.Therefore,when tAH?actual WWTP HRT?> t_FH?obtained by fitting the inffluent respirogram?,it is shown that the pollutants in the actual hydraulic retention time are enough to be degraded by the activated sludge below the discharge standard,that is,the effluent can be reached the discharge standard safely.?5?Combine the two respirograms and summarize the method of analyzing the Respirograms to determine the actual WWTP's processing capacity and the effluent quality whether can be meet the discharge standards.This method can be used to monitor the sewage treatment plant and provide guidance for the rational operation and optimization of the WWTP.