The Study Of Intelligent Early Warning Method For Membrane Fouling In Wastewater Treatment Process By MBR

Membrane Bioreactor(MBR)is a new kind of wastewater treatment technology,which combines membrane separation technology and traditional sludge treatment technology.It has many advantages,such as good water quality,low land occupation,low sludge production and convenient operation and management.It has been widely used in the process of urban wastewater treatment.However,during the process of applying MBR to treat wastewater,membrane fouling is unavoidable.Membrane fouling will result in the decrease of water production,moreover,the increasing of cleaning frequency and replacement frequency of membrane components,which results the increase of energy consumption and cost,has seriously affected the quality of treated water and the application MBR.The effective method of controlling membrane fouling is to predict the situation of membrane fouling accurately.The warning can be put forward before the deterioration of treated water quality,which suggests the staff of the wastewater plant to take corresponding measures.However,at present,there is a lack of the study of early warning method for membrane fouling at home and abroad.In view of this problem,this paper proposes an intelligent early warning method for membrane fouling which containd permeability forecasting method and a warning detection method,and applies this intelligent warning method to wastewater treatment plant in Beijing.The achievements of this paper are showed as below:1.Permeability characteristic analysis and the correct selection of the correlation variable.In the actual operation of the wastewater treatment plants,the pollution status of the membrane is usually characterized by the permeability.Based on the characteristics and historical data of the membrane treatment process,the relationship between the permeability and its process parameters is analyzed,and the 21 kinds of data can be collected by mechanism analysis and partial least squares(PLS)algorithm.The process parameters,including water production,water production pressure,aeration,aerobic zone nitrate,and anoxic area ORP in,are selected by PLS.2.The design of the soft sensor model for permeability.A prediction model based on recursive fuzzy neural network(RFNN)is set up and the inputs is designed by PLS.Based on the multi-step forecast strategy,the prediction model for permeability is set up by using the actual data collected from the wastewater treatment plant.The results show that proposed prediction model based on RFNN and multi-step strategy can predict permeability in the future,thus realizing the prediction of membrane fouling.Compared with other prediction models,the proposed prediction model has better results;3.The warning detection method for membrane fouling is proposed.According to the classification and application requirements of the membrane fouling warning,the method for membrane fouling levels evaluation is analyzed and designed.Membrane pollution is a complicated fuzzy process.The fuzzy comprehensive evaluation(FCE)method is introduced into the field of membrane fouling warning detection,based on the prediction value of permeability and other variables.4.The early warning system for membrane fouling has been set up.In view of the lack of warning system for membrane fouling,an intelligent warning system for membrane fouling is proposed in this paper.In order to ensure the safety of field control of membrane wastewater treatment,the warning system adds gateway isolation,that is,the FameView configuration software is used to read the related process variables from the PLC.Moreover,the collected data is converted to OPC DA/UA and transmitted to the data acquisition module.The warning system adopts the structure of dual network cards to make make the rest of the water plant work properly.The algorithms of membrane fouling prediction and warning detection are embedded into the system in the form of.dll files,and the functions of prediction and warning are realized at the same time when the system is called.The design of the intelligent early warning method for membrane fouling is applied to real wastewater treatment plants in Beijing.Users can query the working state of the system in any access to the Internet.Experimental results demonstrate that both the accuracy and effectiveness of the system for membrane fouling were greatly superior.