MBBR suspended filler biological membrane thickness monitoring and control system

Abstract

The invention relates to the field of water treatment, and discloses an MBBR suspended filler biological membrane thickness monitoring and control system which is mainly composed of a suspended filler biological membrane thickness monitoring module, a suspended filler biological membrane thickness early warning module and a suspended filler biological membrane thickness control module. According to the monitoring module, a suspended filler biological membrane picture obtaining unit obtains a biological membrane picture in real time through an online monitoring device; the picture processing unit processes the picture to obtain the thickness of the biological membrane as monitoring data; the thickness analysis unit further analyzes based on the data; the early warning module is used for judging whether the thickness of the biological membrane is abnormal or not, and giving out early warning if the thickness is abnormal; 2, judging whether the growth or shedding rate of the biological membrane is normal or not, and giving out early warning if the growth or shedding rate is abnormal; and the control module combines monitoring data of the monitoring module and an early warning signal of the early warning module to precisely control the opening degree of an automatic control valve of the aeration module in the MBBR pool, so that the thickness of a biological membrane is kept in an optimal range, and efficient and stable operation of a water treatment system is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and particularly to a monitoring and control system for the thickness of the biofilm of MBBR suspended fillers. Background Art

[0002] The moving bed biofilm reactor (MBBR) is an efficient technology for the biological treatment of sewage and low-pollution water (such as polluted river water, the tail water of sewage treatment plants, rainwater runoff, agricultural runoff, and other similar water bodies). It mainly relies on the biofilm attached to the surface of suspended fillers to degrade pollutants, and the pollutants in sewage and low-pollution water are removed through the metabolic action of microorganisms in the biofilm.

[0003] The thickness of the biofilm is crucial in the process of pollutant degradation in the MBBR system, and its dynamic regulation is the key to optimizing the MBBR process. Different treatment objects require different thicknesses of the biofilm enriched on the surface of MBBR suspended fillers. For example, when treating high-concentration sewage, in order to ensure sufficient biomass to degrade pollutants, a relatively thick biofilm is required. However, an overly thick biofilm will expand the inner anaerobic zone, thereby affecting the treatment effect. When treating low-pollution water, in order to ensure mass transfer efficiency and maintain high microbial activity, it is necessary to control the formation of a thin biofilm. When the effluent needs to meet the Class IV standard of the Environmental Quality Standards for Surface Water (GB3838-2002), it is necessary to precisely regulate the biofilm thickness to balance the proportion of nitrification and denitrification bacteria groups, so as to effectively remove nitrogen pollutants. Thus, precisely controlling the biofilm thickness plays a decisive role in the efficient and stable operation of the MBBR process.

[0004] However, the current control methods for the thickness of the biofilm of MBBR suspended fillers are relatively backward and mostly rely on experience. Generally, the aeration intensity is adjusted through experience or historical data to change the hydraulic shear force, or the filler dosage is adjusted to change the growth space of the biofilm. However, these methods have many problems, including: reaction lag, unable to make adjustments in a timely manner according to changes in water quality, and the control accuracy is not high, making it difficult to keep the biofilm thickness in the best state. For example, excessive aeration not only fails to accurately control the biofilm thickness but also significantly increases the system energy consumption, resulting in energy waste. According to statistics, in MBBR systems using traditional empirical regulation methods, the energy consumption increase caused by improper aeration control accounts for about 20%-30% of the total energy consumption. Therefore, it is very necessary to develop a monitoring and control system for the thickness of the biofilm of MBBR suspended fillers that integrates real-time monitoring, intelligent analysis, and precise regulation. This is of great significance for breaking through the technical bottlenecks of traditional methods such as "response lag - rough control - low energy efficiency" and realizing the optimized operation and energy conservation and consumption reduction of the water treatment process. Summary of the Invention

[0005] The purpose of the present invention is to provide a monitoring and control system for the thickness of the biofilm of MBBR suspended fillers to solve the above technical problems.

[0006] The object of the present invention can be achieved by the following technical solutions: An MBBR suspended packing biofilm thickness monitoring and control system, which is configured in an MBBR water tank. The system includes: A suspended packing biofilm thickness monitoring module, including: An image acquisition unit, which obtains biofilm images of suspended packings in real time based on an on-line monitoring device for the thickness of the suspended packing biofilm; An image processing unit, which is used to process the biofilm images of the suspended packings obtained by the image acquisition unit to obtain the thickness of the suspended packing biofilm and use it as monitoring data; A thickness analysis unit, which further analyzes based on the thickness data of the suspended packing biofilm obtained by the image processing unit; A suspended packing biofilm thickness warning module, which is used to send a warning signal when it is determined that the thickness of the suspended packing biofilm is abnormal; it also sends a warning signal according to the judgment result of whether the growth or shedding rate of the suspended packing biofilm is normal; A suspended packing biofilm thickness control module, which controls the opening degree of the automatic control valve of the aeration module in the MBBR water tank according to the monitoring data of the suspended packing biofilm thickness monitoring module and the warning signal of the warning module.

[0007] As a further technical solution, the working process of the thickness analysis unit is as follows: Compare the thickness of the suspended packing biofilm monitored in real time with the optimal thickness of the suspended packing biofilm corresponding to different water quality treatments preset, and calculate the deviation of the thickness of the suspended packing biofilm ; The expression is: ; where is the actually monitored thickness of the suspended packing biofilm, is the optimal thickness of the suspended packing biofilm determined for different treated water qualities; Compare the deviation of the thickness of the suspended packing biofilm with the preset deviation threshold of the thickness of the suspended packing biofilm : If , it is determined that the thickness of the suspended packing biofilm is abnormal, otherwise, it is determined that the thickness of the suspended packing biofilm is normal; Then analyze the change trend of the thickness of the suspended packing biofilm over time to determine whether the growth or shedding rate of the suspended packing biofilm is normal.

[0008] As a further technical solution, the process of analyzing the change trend of the thickness of the suspended packing biofilm over time is as follows: Obtain the thickness data of the suspended packing biofilm from the suspended packing biofilm image processing unit at preset time intervals, and construct a set of time - series data , is the number of times for collecting the thickness of the suspended packing bio - film; Through the formula: ; the cumulative change amount of the thickness of the suspended packing bio - film is calculated ; wherein, is the time period corresponding to the th time - series data, , are respectively the start time point and the end time point of each time period, is the weight coefficient of each time period, is the maximum value of the thickness of the suspended packing bio - film within each time period, is the minimum value of the thickness of the suspended packing bio - film within each time period, is the preset proportionality coefficient corresponding to each time period; is the curve of the thickness of the suspended packing bio - film changing with time fitted based on the time - series data set, is the influent water quality coefficient, and the expression is: , is the effluent water quality coefficient, and the expression is: ; wherein, is the mean value of any influent water quality parameter, is the number of items of water quality parameters, is the reference value of the corresponding influent water quality parameter, is the mean value of any effluent water quality parameter, is the standard value of the corresponding effluent water quality parameter, , are influence coefficients, which are determined based on historical data and experimental data analysis.

[0009] As a further technical solution, the process of judging whether the growth or shedding rate of the suspended packing bio - film is normal is as follows: Substitute the calculated cumulative change amount of the thickness of the suspended packing bio - film into the formula: to calculate the average change rate of the thickness of the suspended packing bio - film ; If , it is judged that the suspended packing bio - film is in a growth state; If , it is judged that the suspended packing bio - film is in a shedding state; The average change rate of the thickness of the suspended packing bio - film Compare with the preset change rate threshold range for comparison; If and , it is determined that the growth of the suspended packing biofilm is abnormal; If and , it is determined that the shedding of the suspended packing biofilm is abnormal; Otherwise, it is determined that the growth or shedding of the suspended packing biofilm is normal.

[0010] As a further technical solution, the working process of the image processing unit is as follows: Screen the images of the suspended packing biofilm at a set angle, and perform preprocessing operations on the screened images of the suspended packing biofilm. The preprocessing operations include image enhancement, denoising, and normalization; Input the preprocessed images of the suspended packing biofilm into a pre-trained biofilm thickness prediction model based on a convolutional neural network. The biofilm thickness prediction model based on a convolutional neural network includes multiple convolutional layers, pooling layers, and fully connected layers; The biofilm thickness prediction model based on a convolutional neural network extracts features from the input images, learns the texture, edges, and color features of the biofilm through the convolutional layers, and the pooling layers downsample the feature maps to reduce the amount of computation and the number of parameters; The features extracted are mapped to the predicted value of the biofilm thickness through the fully connected layer, and finally the thickness of the suspended packing biofilm is output .

[0011] As a further technical solution, the working process of the suspended packing biofilm thickness control module is as follows: According to the deviation of the suspended packing biofilm thickness and the average change rate calculate to obtain the comprehensive deviation index E; Compare the comprehensive deviation index E with the preset comprehensive deviation threshold ER; If E ≤ ER, it is determined that the thickness of the suspended packing biofilm is normal, and the opening degree of the automatic control valve of the aeration module in the MBBR pool remains the current value K0 unchanged, that is, K = K0; K is the adjusted opening degree value of the automatic control valve; If E > ER, adjust the opening degree value of the automatic control valve of the aeration module in the MBBR pool according to the comprehensive deviation index E.

[0012] As a further technical solution, the process of adjusting the opening degree value K of the automatic control valve of the aeration module in the MBBR pool according to the comprehensive deviation index E is as follows: Through the formula: K = K0 + k(E - ER), where k is the proportionality coefficient; When the deviation of the thickness of the suspended packing biofilm and the average change rate of the thickness of the suspended packing biofilm when, k takes a positive value and the aeration intensity is increased; when and when, k takes a negative value and the aeration intensity is decreased; Compare the calculated opening value K of the automatic control valve with the preset lower limit value , upper limit value ; If K < , then let K = ; If K > , then let K = .

[0013] As a further technical solution, the expression of the comprehensive deviation index E is: ; where , are weight coefficients, and .

[0014] Advantages of the present invention: Through the mutual cooperation of the suspended packing biofilm thickness monitoring module, the suspended packing biofilm thickness early warning module and the suspended packing biofilm thickness control module, the present invention realizes the dynamic supervision of the thickness of the suspended packing biofilm. Once abnormal growth or shedding occurs, an early warning is immediately given, and measures are taken in time to control the thickness of the suspended packing biofilm, comprehensively improving the water treatment capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 It is a schematic structural diagram of an MBBR pool and a suspended packing biofilm thickness detection and control system; Figure 2 It is a system structure block diagram of the present invention.

[0017] Reference numerals: 10, water inlet; 20, water outlet; 30, suspended packing interception grid; 40, aeration pipe; 50, automatic control valve; 60, air diffuser; 70, on-line monitoring device for the thickness of the floating packing biofilm. DETAILED DESCRIPTION OF THE INVENTION

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Please refer to Figure 1 - Figure 2 as shown in the figure, the present invention is a monitoring and control system for the thickness of the MBBR suspended packing biofilm. The system is configured in the MBBR water tank, and the system includes: A monitoring module for the thickness of the MBBR suspended packing biofilm, including: An image acquisition unit that obtains biofilm images of the suspended packing in real time based on an on-line monitoring device for the thickness of the MBBR suspended packing biofilm; An image processing unit for processing the biofilm images of the suspended packing obtained by the image acquisition unit to obtain the thickness of the MBBR suspended packing biofilm and using it as monitoring data; A thickness analysis unit that further analyzes the thickness data of the MBBR suspended packing biofilm obtained by the image processing unit; A warning module for the thickness of the MBBR suspended packing biofilm, which issues a warning signal when it judges that the thickness of the MBBR suspended packing biofilm is abnormal; and also issues a warning signal according to the judgment result of whether the growth or shedding rate of the MBBR suspended packing biofilm is normal; A control module for the thickness of the MBBR suspended packing biofilm, which controls the opening of the automatic control valve of the aeration module in the MBBR water tank according to the monitoring data of the monitoring module for the thickness of the MBBR suspended packing biofilm and the warning signal of the warning module.

[0020] It should be noted that: The MBBR water tank includes: an inlet 10, an outlet 20, an aeration module, an on-line monitoring device 70 for the thickness of the MBBR suspended packing biofilm, a central processing unit, and a suspended packing interception grille 30; the inlet 10 is located on the left side of the MBBR water tank, the outlet 20 is located on the right side of the MBBR water tank, the suspended packing interception grille 30 is located on the side wall inside the MBBR water tank close to the outlet 20, the aeration module is located at the bottom of the MBBR water tank, and multiple on-line monitoring devices 70 for the thickness of the MBBR suspended packing biofilm are provided and located inside the MBBR water tank; Among them, the aeration module includes an air distribution pipe 40, an automatic control valve 50, and an air diffuser 60; the central processing unit includes a monitoring module for the thickness of the MBBR suspended packing biofilm, a warning module for the thickness of the MBBR suspended packing biofilm, and a control module for the thickness of the MBBR suspended packing biofilm.

[0021] In this embodiment, the system consists of three modules: monitoring the thickness of the suspended packing biofilm, early warning, and control. Among them, the monitoring module includes three units: obtaining, processing, and analyzing the thickness of the suspended packing biofilm pictures; the unit for obtaining the suspended packing biofilm pictures obtains the biofilm pictures in real time through an online monitoring device; the picture processing unit processes the pictures to obtain the biofilm thickness as monitoring data; the thickness analysis unit further analyzes based on this data; and the early warning module has two early warning bases: one is to judge whether the biofilm thickness is abnormal, and if it is abnormal, an early warning is issued; the other is to judge whether the growth or shedding rate of the biofilm is normal, and if it is abnormal, an early warning is also issued; finally, the control module combines the monitoring data of the monitoring module and the early warning signal of the early warning module to accurately control the opening of the automatic control valve 50 of the aeration module in the MBBR pool to maintain the biofilm thickness within a suitable range, ensure the efficient and stable operation of the water treatment system, and improve the sewage treatment effect; through the cooperation of the above-mentioned multiple modules, the dynamic monitoring and control of the suspended packing biofilm thickness are realized. Once the growth or shedding is abnormal, an early warning is immediately issued, and measures are taken in a timely manner to control the suspended packing biofilm thickness, comprehensively improving the water treatment capacity.

[0022] The working process of the unit for analyzing the thickness of the suspended packing biofilm is as follows: Compare the thickness of the suspended packing biofilm monitored in real time with the optimal thickness of the suspended packing biofilm corresponding to different water quality treatments preset, and calculate the deviation of the thickness of the suspended packing biofilm ; The expression is: ; where is the actually monitored thickness of the suspended packing biofilm, is the optimal thickness of the suspended packing biofilm determined for different treated water qualities, which is determined according to experimental data and actual operation experience; Compare the deviation of the thickness of the suspended packing biofilm with the preset deviation threshold of the thickness of the suspended packing biofilm : If , it is judged that the thickness of the suspended packing biofilm is abnormal, otherwise, it is judged that the thickness of the suspended packing biofilm is normal; Then analyze the change trend of the thickness of the suspended packing biofilm over time to judge whether the growth or shedding rate of the suspended packing biofilm is normal.

[0023] The process of analyzing the change trend of the thickness of the suspended packing biofilm over time is as follows: Obtain the thickness data of the suspended packing biofilm from the unit for processing the suspended packing biofilm pictures at preset time intervals, and construct time series data sets , is the number of times of collecting the thickness of the suspended packing biofilm; Through the formula: Calculate the cumulative change in the thickness of the suspended packing biofilm ; Wherein, is the time period corresponding to the -th time series data, , are respectively the starting time point and the ending time point of each time period, is the weight coefficient of each time period, determined according to experimental data and actual operation experience, is the maximum value of the thickness of the suspended packing biofilm within each time period, is the minimum value of the thickness of the suspended packing biofilm within each time period, is the preset proportionality coefficient corresponding to each time period, determined according to experimental data and actual operation experience; is the curve of the change of the thickness of the suspended packing biofilm with time fitted based on the time series data set, is the influent water quality coefficient, and the expression is: , is the effluent water quality coefficient, and the expression is: ; Wherein, is the mean value of any influent water quality parameter, is the number of items of water quality parameters, is the reference value of the corresponding influent water quality parameter, is the mean value of any effluent water quality parameter, is the standard value of the corresponding effluent water quality parameter, , are influence coefficients, determined based on historical data and experimental data analysis.

[0024] Through the formula: Calculate the cumulative change in the thickness of the suspended packing biofilm ; Thus, by using the integral method, the change in the thickness of the suspended packing biofilm within the time period corresponding to each time series data is calculated to achieve the accurate calculation of the average cumulative change. At the same time, in order to improve the accuracy of the evaluation of the cumulative change, the extreme value difference within each time period is incorporated into the calculation formula in the form of an exponent, and then the change in the thickness of the suspended packing biofilm is accurately evaluated by combining the cumulative change and the extreme value difference; The process of judging whether the growth or shedding rate of the suspended packing biofilm is normal is: Substitute the calculated cumulative change in the thickness of the suspended packing biofilm into the formula: to calculate the average change rate of the thickness of the suspended packing biofilm; If , it is determined that the suspended packing biofilm is in a growth state; If , it is determined that the suspended packing biofilm is in a shedding state; The average change rate of the thickness of the suspended packing biofilm is compared with the preset change rate threshold interval ; If and , it is determined that the growth of the suspended packing biofilm is abnormal; If and , it is determined that the shedding of the suspended packing biofilm is abnormal; Otherwise, it is determined that the growth or shedding of the suspended packing biofilm is normal.

[0025] In this embodiment, a method for analyzing the thickness of the suspended packing biofilm is provided. Specifically, first, the thickness deviation of the suspended packing biofilm is compared with the preset thickness deviation threshold of the suspended packing biofilm to determine whether the current thickness of the suspended packing biofilm is normal. If it is abnormal, a warning signal is issued. If it is normal, then the change trend of the thickness of the suspended packing biofilm over time is analyzed to determine whether the growth or shedding rate of the suspended packing biofilm is normal, so as to realize the monitoring of the growth or shedding rate of the suspended packing biofilm by combining time series, improve the dynamic monitoring ability of the thickness of the suspended packing biofilm, and provide reliable support for timely warning of abnormal changes in the thickness of the suspended packing biofilm in the future.

[0026] The working process of the image processing unit is as follows: Screen the pictures of the suspended packing biofilm at a set angle, and perform preprocessing operations on the screened pictures of the suspended packing biofilm. The preprocessing operations include image enhancement, denoising, and normalization; Input the preprocessed pictures of the suspended packing biofilm into a pre-trained biofilm thickness prediction model based on a convolutional neural network. The biofilm thickness prediction model based on a convolutional neural network includes multiple convolutional layers, pooling layers, and fully connected layers; The biofilm thickness prediction model based on a convolutional neural network extracts features from the input pictures, learns the texture, edges, and color features of the biofilm through convolutional layers, and the pooling layers downsample the feature maps to reduce the amount of calculation and the number of parameters; After passing through the fully connected layer, the extracted features are mapped to the predicted value of the biofilm thickness, and finally the thickness of the suspended packing biofilm is output .

[0027] In this embodiment, by screening pictures at specific angles, the consistency and effectiveness of the input data can be ensured, and the preprocessing operation can improve the picture quality, making it easier for the model to learn key features. CNN model: Convolutional neural network is widely used in the field of image recognition and processing, and can automatically learn discriminative features from images. The combination of multiple convolutional layers and pooling layers can gradually extract different levels of features of the biofilm, and the fully connected layer integrates these features and outputs the final thickness prediction value. By using the trained model, the input pictures are directly processed to output the biofilm thickness, avoiding the complex edge detection and geometric calculation steps in the traditional method.

[0028] The working process of the suspended packing biofilm thickness control module is as follows: According to the deviation of the suspended packing biofilm thickness and the average change rate calculate to obtain the comprehensive deviation index E. The expression of the comprehensive deviation index E is: ; where , are weight coefficients, and ; Compare the comprehensive deviation index E with the preset comprehensive deviation threshold ER; If E ≤ ER, it is judged that the thickness of the suspended packing biofilm is normal, and the opening degree of the automatic control valve of the aeration module in the MBBR water tank remains the current value K0 unchanged, that is, K = K0; K is the adjusted opening degree value of the automatic control valve; If E > ER, adjust the opening degree value of the automatic control valve of the aeration module in the MBBR water tank according to the comprehensive deviation index E.

[0029] The process of adjusting the opening degree value K of the automatic control valve of the aeration module in the MBBR water tank according to the comprehensive deviation index E is as follows: Through the formula: K = K0 + k(E - ER), k is a proportionality coefficient, which is determined according to experimental data and actual operation experience; when the deviation of the suspended packing biofilm thickness and the average change rate of the suspended packing biofilm thickness , k takes a positive value to increase the aeration intensity; when and , k takes a negative value to reduce the aeration intensity; Compare the calculated opening degree value K of the automatic control valve with the preset lower limit value , upper limit value ; if K < , then let K = ; if K > , then let K = .

[0030] In this embodiment, based on the monitoring data of the suspended packing biofilm thickness monitoring module and the warning signal of the warning module, the opening degree of the automatic control valve of the aeration module is precisely controlled, so that the biofilm thickness can be maintained within the optimal biofilm thickness range determined for different treated water qualities. The biofilm with an appropriate thickness can provide a good living environment for microorganisms, enabling the microorganisms to fully play their role in decomposing and transforming pollutants in the water, thereby improving the removal rate of organic matter and effectively reducing indicators such as chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the sewage; When it is monitored that the biofilm thickness exceeds the warning threshold range, or the growth or shedding rate of the biofilm is abnormal, the control module can quickly respond and timely adjust the aeration intensity. For example, when the biofilm is too thick, increasing the aeration intensity can promote the shedding of the biofilm and prevent problems such as internal anaerobic conditions and reduced mass transfer efficiency caused by the too thick biofilm; when the biofilm is too thin, reducing the aeration intensity is beneficial to the growth and recovery of the biofilm and ensures the normal operation of the system; the above timely adjustment mechanism can effectively avoid system failures and fluctuations in treatment effects caused by abnormal biofilm thickness, enhancing the anti-interference ability and stability of the system; Aeration is one of the main energy-consuming links in the operation process of the MBBR system. The control module in the present invention precisely controls the opening degree of the automatic control valve of the aeration module, avoiding unnecessary over-aeration or under-aeration situations, providing an appropriate amount of oxygen according to the actual needs of the biofilm, and being able to minimize the aeration energy consumption on the premise of ensuring the sewage treatment effect, thereby reducing the operating cost of the system.

[0031] It should be noted that: the calculation formulas and each parameter participating in the operation in the present invention are all pre-dimensionless processed, and the process of dimensionless processing is well-known in the industry and will not be described here.

[0032] The above has described a detailed description of an embodiment of the present invention, but the content described is only the preferred embodiment of the present invention and cannot be considered as used to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. An MBBR suspended packing biofilm thickness monitoring and control system, which is configured in an MBBR pool, and is characterized in that, The system includes: A suspended packing biofilm thickness monitoring module, including: An image acquisition unit that acquires biofilm images of the suspended packing in real time based on an on-line monitoring device for the thickness of the suspended packing biofilm; An image processing unit that processes the biofilm images of the suspended packing acquired by the image acquisition unit to obtain the thickness of the suspended packing biofilm and uses it as monitoring data; A thickness analysis unit that further analyzes based on the thickness data of the suspended packing biofilm obtained by the image processing unit; A suspended packing biofilm thickness warning module that issues a warning signal when it determines that the thickness of the suspended packing biofilm is abnormal; and also issues a warning signal according to the judgment result of whether the growth or shedding rate of the suspended packing biofilm is normal; A suspended packing biofilm thickness control module that controls the opening degree of the automatic control valve of the aeration module in the MBBR pool according to the monitoring data of the suspended packing biofilm thickness monitoring module and the warning signal of the warning module.

2. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 1, wherein The working process of the thickness analysis unit is as follows: Compare the thickness of the suspended packing biofilm monitored in real time with the optimal thickness of the suspended packing biofilm corresponding to different water quality treatments preset, and calculate the deviation of the thickness of the suspended packing biofilm ; The expression is: ; where is the actually monitored thickness of the suspended packing biofilm, is the optimal thickness of the suspended packing biofilm determined for different treated water qualities; Compare the deviation of the thickness of the suspended packing biofilm with the preset threshold value of the deviation of the thickness of the suspended packing biofilm : If , it is determined that the thickness of the suspended packing biofilm is abnormal; otherwise, it is determined that the thickness of the suspended packing biofilm is normal; Re-analyze the change trend of the suspended packing biofilm thickness over time to judge whether the growth or shedding rate of the suspended packing biofilm is normal.

3. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 2, characterized in that, The process of analyzing the change trend of the suspended packing biofilm thickness over time is as follows: Obtain the suspended packing biofilm thickness data from the suspended packing biofilm image processing unit at preset time intervals, and construct time series data sets , being the number of times of collecting the suspended packing biofilm thickness; Through the formula: ； Calculate the cumulative change in the thickness of the suspended packing biofilm ; Wherein, is the time period corresponding to the th time series data, and are respectively the start time point and the end time point of each time period, is the weight coefficient of each time period, is the maximum value of the thickness of the suspended packing biofilm within each time period, is the minimum value of the thickness of the suspended packing biofilm within each time period, is the preset proportionality coefficient corresponding to each time period; is the curve of the thickness of the suspended packing biofilm varying with time fitted based on the time series data set, is the influent water quality coefficient, and the expression is: , is the effluent water quality coefficient, and the expression is: ; wherein, is the mean value of any influent water quality parameter, is the number of items of the water quality parameters, is the reference value of the corresponding influent water quality parameter, is the mean value of any effluent water quality parameter, is the standard value of the corresponding effluent water quality parameter, and are influence coefficients.

4. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 3, characterized in that, The process of judging whether the growth or shedding rate of the suspended packing biofilm is normal is as follows: Substitute the calculated cumulative change amount of the suspended packing biofilm thickness into the formula: to calculate the average change rate of the suspended packing biofilm thickness ; If , it is determined that the suspended packing biofilm is in a growth state; If , it is determined that the suspended packing biofilm is in a shedding state; Compare the average change rate of the thickness of the suspended packing biofilm with a preset change rate threshold range for comparison; If and , it is determined that the growth of the suspended packing biofilm is abnormal; If and , it is determined that the suspended packing biofilm shedding is abnormal; Otherwise, it is judged that the growth or shedding of the suspended packing biofilm is normal.

5. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 4, characterized in that The working process of the image processing unit is as follows: Screen the biofilm images of the suspended packing at a set angle and perform preprocessing operations on the screened biofilm images of the suspended packing. The preprocessing operations include image enhancement, denoising, and normalization; Input the preprocessed biofilm images of the suspended packing into a pre-trained biofilm thickness prediction model based on a convolutional neural network. The biofilm thickness prediction model based on a convolutional neural network includes multiple convolutional layers, pooling layers, and fully connected layers; The biofilm thickness prediction model based on a convolutional neural network extracts features from the input images, learns the texture, edges, and color features of the biofilm through the convolutional layers, and the pooling layers downsample the feature maps to reduce the amount of calculation and the number of parameters; The extracted features are mapped to the predicted value of the biofilm thickness through the fully connected layer, and finally the biofilm thickness of the suspended packing is output .

6. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 1 or 4, characterized in that, The working process of the suspended packing biofilm thickness control module is as follows: According to the deviation of the thickness of the suspended packing biofilm and the average change rate Calculate to obtain the comprehensive deviation index E; Compare the comprehensive deviation index E with a preset comprehensive deviation threshold ER; If E ≤ ER, it is judged that the thickness of the suspended packing biofilm is normal, and the opening degree of the automatic control valve of the aeration module in the MBBR pool remains the current value K0 unchanged, that is, K = K0; K is the adjusted opening degree value of the automatic control valve; If E > ER, adjust the opening degree value of the automatic control valve of the aeration module in the MBBR pool according to the comprehensive deviation index E.

7. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 6, wherein The process of adjusting the opening degree value K of the automatic control valve of the aeration module in the MBBR pool according to the comprehensive deviation index E is as follows: Through the formula: K = K0 + k(E - ER), where k is a proportionality coefficient; When the deviation of the thickness of the suspended packing biofilm and the average change rate of the thickness of the suspended packing biofilm then k takes a positive value and the aeration intensity is increased; when and then k takes a negative value and the aeration intensity is decreased; Compare the calculated opening value K of the automatic control valve with the preset lower limit value , upper limit value ; If K < , then set K = ; If K > , then set K = .

8. The MBBR suspended packing biofilm thickness monitoring and control system according to claim 6, characterized in that, The expression of the comprehensive deviation index E is as follows: ; where , are weighting coefficients, and .

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