BioWin-based MABR aeration control system and method

Abstract

The invention provides a BioWin-based MABR aeration control system and a BioWin-based MABR aeration control method. A set of control method suitable for the MABR aeration system is established, water quality indexes and operation parameters which are measured in real time are input into BioWin software, theoretical oxygen demand and actual oxygen transfer rate are obtained through calculation by using a BW controller, regulation and control quantity is obtained through PID control calculation, regulation and control signals are transmitted to a PLC system by the BW controller, and the PLC system is used for controlling the aeration of the MABR aeration system. And the PLC system regulates and controls the regulating valve and the aeration fan and receives a feedback signal, so that accurate control on the aeration system is finally realized. The system has the advantages that real-time data are input into the BW controller through online monitored water quality indexes and operating parameters, theoretical oxygen demand and actual oxygen transfer rate are obtained through calculation, and the aeration air volume is optimized, the denitrification efficiency is improved and the aeration energy consumption is reduced through PID (Proportion Integration Differentiation) control; water quality indexes and operation parameters are changed, the variation trend of theoretical oxygen demand and actual oxygen transfer rate is predicted, the aeration air volume is regulated and controlled, and air volume waste is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and specifically to a BioWin-based MABR aeration control system and method. Background Technique

[0002] As a new sewage treatment technology, the Membrane Aerated Biofilm Reactor (MABR) combines the advantages of the biofilm method and bubbleless aeration, and has characteristics such as high efficiency and energy conservation. However, the MABR process is affected by various factors during actual operation, such as dissolved oxygen concentration, substrate concentration, microbial community structure, etc., resulting in unstable treatment effects and difficulty in achieving the best operating state. Taking aeration control as an example, traditional operation control methods often rely on the empirical range of dissolved oxygen, lacking accuracy and scientificity, and unable to fully exploit the energy-saving and carbon-reducing potential of the MABR process.

[0003] As a widely used simulation software, BioWin can perform real-time simulation analysis and even prediction on sewage treatment systems. However, the current method of combining BioWin with the MABR process for optimized operation is not yet perfect, and there is an urgent need to develop a more effective BioWin-based MABR aeration control system and method. Summary of the Invention

[0004] Aiming at the problems in the prior art that the aeration volume of the MABR process cannot be accurately regulated and the oxygen utilization efficiency needs to be improved, the present invention aims to provide a BioWin-based MABR aeration control system and method, which uses a BW controller to calculate the theoretical oxygen demand and the actual oxygen transfer rate, optimizes the aeration air volume through PID control, improves the denitrification efficiency, and reduces the aeration energy consumption; changes water quality indicators and operation parameters, predicts the change trends of the theoretical oxygen demand and the actual oxygen transfer rate, and regulates the aeration air volume to reduce air volume waste. To achieve the above technical features, the technical solution adopted by the present invention is as follows: A BioWin-based MABR aeration control system is installed in the anoxic section of the sewage treatment system, and includes a monitoring feedforward module, a calculation and control module, and an execution and feedback module.

[0005] The monitoring feedforward module is arranged in the anoxic section and includes a sewage flowmeter, an on-line COD monitor, an on-line TN monitor, an on-line NH3-N monitor, a temperature sensor, an OTE on-line monitor, a DO on-line monitor, and an air flowmeter, which are used to monitor the sewage flow, water quality indicators, sewage temperature, oxygen transfer performance indicators and output feedforward signals; The calculation and control module is arranged in the anoxic section and includes a BW controller and a PLC system. It is connected to the monitoring feedforward module and the execution feedback module. The feedforward signal is input into the BW controller, and through PID control, a regulation signal is output to the PLC system. The PLC system outputs a regulation signal to the execution feedback module and receives the feedback signal from the execution feedback module, and then outputs the feedback signal to the BW controller. The execution feedback module is arranged in the anoxic section and includes a regulating valve and an aeration blower. It is connected to the calculation and control module and is used to receive the regulation signal and output the feedback signal to the calculation and control module.

[0006] Furthermore, the anoxic section includes an anoxic tank, an MABR membrane box, and an aeration pipeline. The MABR membrane box is installed in the anoxic tank, and the aeration pipeline connects the aeration blower to the MABR membrane box.

[0007] Furthermore, the sewage flowmeter is installed at the inlet of the anoxic section. The COD on-line monitor is installed at the inlet and outlet of the anoxic section respectively. The TN on-line monitor is installed at the inlet of the anoxic section. The NH3-N on-line monitor is installed at the outlet of the anoxic section. The temperature sensor, OTE on-line monitor, and DO on-line monitor are installed above the MABR membrane box, and various parameters are input into the BW controller. The regulating valve and the air flowmeter are installed on the aeration pipeline, and the valve opening signal and the air flow in the aeration pipeline are fed back to the PLC system.

[0008] Furthermore, the sewage flowmeter selects at least one of an ultrasonic flowmeter and an electromagnetic flowmeter. The regulating valve selects at least one of a ball valve, a butterfly valve, and a gate valve. The aeration blower selects at least one of a Roots blower, an axial flow blower, a centrifugal blower, or a suspended blower.

[0009] Furthermore, the theoretical oxygen demand calculation formula pre-stored in the BW controller is:

[0010] where ——Theoretical oxygen demand, kg / h; ——Inflow rate of the anoxic tank, m 3 / h; ——COD concentration of the influent of the anoxic tank, mg / L; ——COD concentration of the effluent of the anoxic tank, mg / L; ——TN concentration of the influent of the anoxic tank, mg / L; ——NH3-N concentration in the effluent of the anoxic tank, mg / L.

[0011] Furthermore, the calculation formula of the actual oxygen transfer rate in the BW controller includes the calculation of the standard oxygen transfer efficiency and the oxygen mass transfer rate, specifically: ; wherein, ——Standard oxygen transfer efficiency, %; ——Oxygen transfer efficiency, %; ——Actual water temperature, °C; ——Saturated dissolved oxygen concentration in clear water at 20°C, mg / L; ——Saturated dissolved oxygen concentration in clear water at T°C, mg / L; ——Actual dissolved oxygen concentration, mg / L; ——Ratio of oxygen mass transfer effect between sewage and clear water; ——Ratio of saturated dissolved oxygen concentration between sewage and clear water, taking 1; ; wherein, ——Oxygen mass transfer rate, kg / h; ——Density of oxygen under standard conditions, kg / m 3 ; ——Air flow rate, m 3 / h; ——Ratio of oxygen mass transfer effect between sewage and clear water; ——Standard oxygen transfer efficiency, %.

[0012] A technical solution is also provided, a MABR aeration control method based on BioWin, using the control system as described above, including the following steps: S1. Take the real-time data of the sewage flowmeter, COD on-line monitor, TN on-line monitor, and NH3-N on-line monitor as feedforward parameters, input them into the BW controller, and calculate the theoretical oxygen demand TOD according to the theoretical oxygen demand calculation formula described in claim 5; S2. Take the real-time data of the air flow rate of the aeration pipe, water temperature, DO, and OTE as feedforward parameters, input them into the BW controller, and calculate the actual oxygen transfer rate OTR according to the actual oxygen transfer rate calculation formula described in Claim 6. S3. Establish TOD and OTR variables in the BW controller. Adopt the PID control method to calculate the deviation e(t) = OTR(t) - TOD(t) based on the target value TOD and the actual value OTR, and through the formula: Calculate the control quantity u(t); where, Kp is the proportional coefficient; Ki is the integral coefficient; Kd is the differential coefficient; S4. According to the calculation result of the BW controller, transmit the regulation signal to the PLC system. The PLC system regulates the control valve and the aeration fan, and receives the feedback signals of the opening degree of the control valve and the air flow rate of the aeration pipe to achieve precise control of the aeration system.

[0013] Further, in the step S1, by arranging COD online monitors, TN online monitors, and NH3-N online monitors at the inlet and outlet of the anoxic section, obtain the pollutant concentration difference between the inlet and outlet water, calculate the pollutant reduction amount to determine the theoretical oxygen demand.

[0014] Further, in the step S2, by arranging a temperature sensor, an OTE online monitor, and a DO online monitor above the MABR membrane box, obtain the sewage temperature, oxygen transfer efficiency, and dissolved oxygen concentration, and combine with the real-time data of the air flow meter on the aeration pipeline to calculate the actual oxygen transfer rate.

[0015] Further, in the step S3, the PID control method realizes the dynamic regulation of the control valve and the aeration fan by adjusting the proportional coefficient Kp, the integral coefficient Ki, and the differential coefficient Kd in real time, and predicts the influence of the change of operating parameters on the theoretical oxygen demand and the actual oxygen transfer rate to optimize the aeration air volume.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The system has a simple and clear structure, is convenient to install in the existing anoxic tank without civil engineering; uses general instruments and equipment, is convenient for replacement and maintenance, and is conducive to popularization; 2. Each detection instrument can monitor the changes of parameters such as water volume, water quality, and temperature in real time, so as to control the oxygen demand of MABR in real time and accurately. Through the cooperation of the feedforward - calculation - control - feedback - control of the feedforward module, calculation control module, and execution feedback module, regulate the opening degree of the control valve and the output flow rate of the aeration fan to improve the biological nitrogen removal effect and reduce the waste of air volume. Description of the Drawings

[0017] Figure 1 Schematic diagram of the aeration control system provided by the embodiment of the present invention; Figure 2 Schematic diagram of the principle of the aeration control system of the embodiment of the present invention.

[0018] In the figure: Anoxic section 1, anoxic tank 11, MABR membrane box 12, aeration pipeline 13, regulating valve 14, aeration blower 15; Monitoring feedforward module 2, sewage flowmeter 21, COD on-line monitor 22, TN on-line monitor 23, NH3-N on-line monitor 24, temperature sensor 25, OTE on-line monitor 26, DO on-line monitor 27, air flowmeter 28; BW controller 3, PLC system 4. Specific implementation manner

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1: This embodiment provides a MABR aeration control system based on BioWin, including a monitoring feedforward module 2, a calculation control module, and an execution feedback module.

[0021] The monitoring feedforward module 2 is arranged in the anoxic section 1 and includes a sewage flowmeter 21, a COD on-line monitor 22, a TN on-line monitor 23, an NH3-N on-line monitor 24, a temperature sensor 25, an OTE on-line monitor 26, a DO on-line monitor 27, and an air flowmeter 28, and is used for monitoring sewage flow, water quality indexes, sewage temperature, oxygen transfer performance indexes and outputting a feedforward signal; The calculation control module is arranged in the anoxic section 1 and includes a BW controller and a PLC system 4, is connected to the monitoring feedforward module and the execution feedback module, inputs the feedforward signal into the BW controller, outputs a regulation signal to the PLC system 4 through PID control, the PLC system 4 outputs a regulation signal to the execution feedback module, and receives the feedback signal of the execution feedback module and outputs a feedback signal to the BW controller; The execution feedback module is arranged in the anoxic section 1 and includes a regulating valve 14 and an aeration blower, is connected to the calculation control module, and is used for receiving a regulation signal and outputting a feedback signal to the calculation control module.

[0022] As Figure 1 shown, the COD on-line monitor 22 is respectively installed at the water inlet and outlet of the anoxic section 1, the TN on-line monitor 23 is installed at the water inlet of the anoxic section 1, the NH3-N on-line monitor 24 is installed at the water outlet of the anoxic section 1, and the temperature sensor 25, OTE on-line monitor 26 and DO on-line monitor 27 are installed above the MABR membrane box 12, and various parameters are input into the BW controller; the regulating valve 14 and the air flowmeter 28 are installed on the aeration pipeline 13, and the valve opening signal and the air flow of the aeration pipeline 13 are fed back to the PLC system 4.

[0023] Among them, in this embodiment, the monitoring feedforward module adopts an electromagnetic flowmeter, a redox potential titration method COD on-line monitor 22, an electrochemistry analysis method TN on-line monitor 23, an electrochemistry analysis method NH3-N on-line monitor 24, a thermistor water temperature sensor, an OTE detector based on gas analysis, a polarographic dissolved oxygen meter, a core-type air flowmeter 28, etc., and converts the measured value into an analog signal and transmits it to the BW controller in real time; the PLC system 4 in this embodiment adopts the Siemens S7-300 series, which is composed of a CPU module, a signal module (SM), a function module (FM), etc., supports up to 32 modules at most, can be flexibly configured, and has strong expansion ability; the regulating valve 14 in this embodiment adopts an electric butterfly valve, and the aeration blower adopts a Roots blower, and converts the measured value into an analog signal and transmits it to the BW controller in real time.

[0024] The real-time data of the sewage flowmeter 21, COD on-line monitor 22, TN on-line monitor 23, and NH3-N on-line monitor 24 are used as feedforward parameters and input into the BW simulator for simulation calculation. The calculation formula is:

[0025] Among them, ——Theoretical oxygen demand, kg / h; ——Influent flow rate of the anoxic tank, m 3 / h; ——Influent COD concentration of the anoxic tank, mg / L; ——Effluent COD concentration of the anoxic tank, mg / L; ——Influent TN concentration of the anoxic tank, mg / L; ——Effluent NH3-N concentration of the anoxic tank, mg / L.

[0026] Take the real-time data of the air flow rate of the aeration pipe, water temperature, DO, and OTE as feed-forward parameters and input them into the BW simulator for simulation calculation. The calculation formula is:

[0027] Wherein, —— Standard oxygen transfer efficiency, %; —— Oxygen transfer efficiency, %; —— Actual water temperature, °C; —— Saturated dissolved oxygen concentration of clear water at 20°C, mg / L; —— Saturated dissolved oxygen concentration of clear water at T°C, mg / L; —— Actual dissolved oxygen concentration, mg / L; —— Ratio of oxygen mass transfer effect between sewage and clear water; —— Ratio of saturated dissolved oxygen concentration between sewage and clear water, take 1.

[0028]

[0029] Wherein, —— Oxygen mass transfer rate, kg / h; —— Density of oxygen under standard conditions, kg / m 3 ; —— Air flow rate, m3 / h; —— Ratio of oxygen mass transfer effect between sewage and clear water; —— Standard oxygen transfer efficiency, %.

[0030] Example 2: As Figure 2 shown, this embodiment provides an aeration control method using the MABR aeration control system based on BioWin in Embodiment 1, including the following steps: S1: The sewage flowmeter 21, COD on-line monitor 22, TN on-line monitor 23, and NH3-N on-line monitor 24 take the real-time data of the sewage flow rate and water quality indexes as feed-forward parameters and calculate the theoretical oxygen demand according to formula (1) kg / h; S2: The aeration blower outputs air, which successively passes through the regulating valve 14 and the air flowmeter 28 on the aeration pipeline 13, and the air is transmitted to the bottom of the MABR membrane box 12. The air moves upward through the inner cavity of the membrane filaments and escapes from the top of the MABR membrane box 12. The probes of the temperature sensor 25, the OTE on-line monitor 26, and the DO on-line monitor 27 are inserted into the sewage above the MABR membrane box 12. The air flowmeter 28 is installed on the aeration pipeline 13, and the real-time data of the sewage temperature, oxygen transfer efficiency, dissolved oxygen value, and air flow are used as feed-forward parameters and respectively input into the BW controller, and the actual oxygen transfer rate is calculated according to formulas (2) and (3). kg / h; S3: Two user-defined variables, TOD and OTR, are established in the BW controller, and the results are presented on the BioWin software interface and the display screen of the PLC system 4. The PID control mode is selected to perform PID control operations on the target value TOD and the actual value OTR, and the deviation e(t) and the control quantity u(t) are calculated. Specifically: e(t) is linearly combined according to the proportionality Kp, integral Ti, and derivative Td to form the control quantity u(t). The specific formula is as follows: (4) where e(t) = OTR(t) - TOD(t); S4: According to the calculation result of the BW controller, the regulation signal is transmitted to the PLC system 4, and the PLC system 4 regulates the regulating valve 14 and the aeration blower 15. The opening degree of the regulating valve 14 is maintained at 100%, and the air output of the aeration blower 15 is reduced from 660 m 3 / h to 560 m 3 / h, realizing the precise control of the aeration system, improving the biological nitrogen removal efficiency, and reducing the waste of air volume.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A BioWin-based MABR aeration control system is installed in the anoxic section of the sewage treatment system, characterized in that: It includes a monitoring feedforward module, a calculation control module, and an execution feedback module. The monitoring feedforward module is arranged in the anoxic section and includes a sewage flowmeter, a COD on-line monitor, a TN on-line monitor, an NH3-N on-line monitor, a temperature sensor, an OTE on-line monitor, a DO on-line monitor, and an air flowmeter, which are used to monitor the sewage flow, water quality indicators, sewage temperature, oxygen transfer performance indicators and output feedforward signals. The calculation control module is arranged in the anoxic section and includes a BW controller and a PLC system, which are connected to the monitoring feedforward module and the execution feedback module. The feedforward signal is input into the BW controller, and the regulation signal is output to the PLC system through PID control. The PLC system outputs the regulation signal to the execution feedback module and receives the feedback signal of the execution feedback module, and outputs the feedback signal to the BW controller. The execution feedback module is arranged in the anoxic section and includes a regulating valve and an aeration blower, which are connected to the calculation control module and are used to receive the regulation signal and output the feedback signal to the calculation control module.

2. The MABR aeration control system based on BioWin according to claim 1, characterized in that: The anoxic section includes an anoxic tank, an MABR membrane box, and an aeration pipeline. The MABR membrane box is installed in the anoxic tank, and the aeration pipeline connects the aeration blower with the MABR membrane box.

3. The MABR aeration control system based on BioWin according to claim 1, wherein: The sewage flowmeter is installed at the inlet of the anoxic section. The COD on-line monitor is installed at the inlet and outlet of the anoxic section respectively. The TN on-line monitor is installed at the inlet of the anoxic section. The NH3-N on-line monitor is installed at the outlet of the anoxic section. The temperature sensor, OTE on-line monitor, and DO on-line monitor are installed above the MABR membrane box to input various parameters into the BW controller. The regulating valve and the air flowmeter are installed on the aeration pipeline to feedback the valve opening signal and the air flow of the aeration pipeline to the PLC system.

4. The MABR aeration control system based on BioWin according to claim 3, characterized in that: The sewage flowmeter selects at least one of an ultrasonic flowmeter and an electromagnetic flowmeter. The regulating valve selects at least one of a ball valve, a butterfly valve, and a gate valve. The aeration blower selects at least one of a Roots blower, an axial flow blower, a centrifugal blower, and a suspended blower.

5. The MABR aeration control system based on BioWin according to claim 1, wherein: The theoretical oxygen demand calculation formula pre-stored in the BW controller is: Where, —— Theoretical oxygen demand, kg / h; —— Influent flow rate of anoxic tank, m 3 / h; —— COD concentration of influent water in anoxic tank, mg / L; —— COD concentration of the effluent from the anoxic tank, mg / L; —— TN concentration of influent water in anoxic tank, mg / L; —— NH3-N concentration in the effluent of the anoxic tank, mg / L.

6. The MABR aeration control system based on BioWin according to claim 5, characterized in that: The actual oxygen transfer rate calculation formula in the BW controller includes standard oxygen transfer efficiency calculation and oxygen mass transfer rate calculation, specifically: ； Where, —— Standard oxygen transfer efficiency, %; ——Oxygen transfer efficiency, %; ——Actual water temperature, °C; ——Dissolved oxygen concentration saturated with fresh water at 20 °C, mg / L; ——Saturated dissolved oxygen concentration of clear water at T℃, mg / L; ——Actual dissolved oxygen concentration, mg / L; ——The ratio of the oxygen mass transfer effect between sewage and clean water; —— The ratio of the saturated dissolved oxygen concentration of sewage to that of clean water, taking 1; ； Where, —— Oxygen mass transfer rate, kg / h; —— Density of oxygen under standard conditions, kg / m 3 ; —— Air flow rate, m 3 / h; —— The ratio of the oxygen mass transfer effect between sewage and clean water; —— Standard oxygen transfer efficiency, %.

7. A MABR aeration control method based on BioWin, characterized in that, Using the control system according to any one of claims 1 to 6, it includes the following steps: S1. Take the real-time data of the sewage flowmeter, COD on-line monitor, TN on-line monitor, and NH3-N on-line monitor as feedforward parameters, input them into the BW controller, and calculate the theoretical oxygen demand TOD according to the theoretical oxygen demand calculation formula described in claim 5. S2. Take the real-time data of the air flow of the aeration pipe, water temperature, DO, and OTE as feedforward parameters, input them into the BW controller, and calculate the actual oxygen transfer rate OTR according to the actual oxygen transfer rate calculation formula described in claim 6. S3. Establish TOD and OTR variables in the BW controller. Adopt the PID control method to calculate the deviation e(t) = OTR(t) - TOD(t) according to the target value TOD and the actual value OTR, and through the formula: ; Calculate the control quantity u(t); where Kp is the proportionality coefficient; Ki is the integral coefficient; Kd is the differential coefficient; S4. According to the calculation result of the BW controller, transmit the control signal to the PLC system. The PLC system regulates the control valve and the aeration fan, and receives the feedback signals of the opening degree of the control valve and the air flow rate of the aeration pipe to achieve precise control of the aeration system.

8. A MABR aeration control method based on BioWin according to claim 7, characterized in that: In the step S1, by arranging COD on-line monitors, TN on-line monitors and NH3-N on-line monitors at the inlet and outlet of the anoxic section, obtain the pollutant concentration difference between the influent and the effluent, and calculate the pollutant reduction amount to determine the theoretical oxygen demand.

9. A MABR aeration control method based on BioWin according to claim 7, characterized in that: In the step S2, by arranging a temperature sensor, an OTE on-line monitor and a DO on-line monitor above the MABR membrane box, obtain the sewage temperature, the oxygen transfer efficiency and the dissolved oxygen concentration, and combine the real-time data of the air flow meter on the aeration pipe to calculate the actual oxygen transfer rate.

10. A MABR aeration control method based on BioWin according to claim 7, characterized in that: In the step S3, the PID control method realizes the dynamic regulation of the control valve and the aeration fan by adjusting the proportionality coefficient Kp, the integral coefficient Ki and the differential coefficient Kd in real time, and predicts the influence of the change of operating parameters on the theoretical oxygen demand and the actual oxygen transfer rate, and optimizes the aeration air volume.

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