An intermittent air stripping backflow sewage treatment method, device and system based on ORP feedback

Abstract

The present application relates to sewage treatment technical field, more specifically, the present application provides a kind of intermittent air-lift backflow sewage treatment method, device and system based on ORP feedback.The present application uses air-lift sludge circulation and air-lift digestion liquid circulation to replace traditional circulating pump, uses the pulse generated in air-lifting process to realize the stirring mixing of anaerobic zone and anoxic zone, without separately setting underwater agitator, reduces equipment investment and maintenance cost.At the same time, air-lifting intensity is controlled by ORP feedback, the amount of air brought by backflow can be accurately controlled, anaerobic / anoxic environment is avoided to be destroyed, energy consumption is significantly reduced;and the ORP of each zone is cyclically fluctuated in respective preset range according to preset period, variable growth environment is actively created, the microbial population type of anaerobic zone, anoxic zone and aerobic zone is more, quantity is more extensive, and always in active state.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to a wastewater treatment method, apparatus, and system based on ORP feedback and intermittent airlift reflux. Background Technology

[0002] In the field of industrial wastewater treatment, the A²O process is widely used due to its excellent nitrogen and phosphorus removal effects. Traditional A²O processes require a large reflux system, including sludge reflux (external reflux) and mixed liquor reflux (internal reflux), which is usually achieved using circulating pumps. This results in high energy consumption and complex operation and management, making it difficult to adapt to the variable characteristics of industrial wastewater.

[0003] In existing technologies, anoxic tanks are typically equipped with ORP (oxidation-reduction potential) sensors to detect the oxidation-reduction potential within the tank. However, these ORP sensors only have a detection function and do not form a control loop with the actuators. If significant fluctuations in ORP occur due to changes in water quality or quantity, the system cannot self-regulate, hindering stable operation and accident early warning. Furthermore, a consistently stable ORP value in the anoxic tank only benefits microbial populations adapted to that value, hindering the growth of other populations and resulting in a homogeneous biological population that struggles to adapt to fluctuations in industrial wastewater quality.

[0004] A dissolved oxygen (DO) meter is installed at the end of the aerobic tank to detect and control the dissolved oxygen level, thereby adjusting parameters such as blower flow and pressure. However, because the DO meter is installed at the end of the aerobic tank, it cannot detect and provide timely feedback on changes in water quality and quantity at the inlet, resulting in a control lag. Furthermore, DO meters are expensive, and typically only one is installed, making it difficult to comprehensively reflect the operational status of the aerobic tank.

[0005] The existing reflux system uses a circulation pump to reflux at a fixed flow rate. When the incoming water fluctuates significantly, it cannot adjust the reflux flow rate in a timely manner to reduce the impact on the biological system. The circulation pump has high operating and maintenance costs and requires an underwater agitator to ensure mixing in the tank, further increasing equipment investment and energy consumption.

[0006] In addition, the long-term stable DO value at the end of the aerobic tank also leads to a single biological population in the aerobic tank, which is not conducive to the treatment of industrial wastewater with variable water quality. Summary of the Invention

[0007] This invention aims to provide a wastewater treatment method, apparatus, and system based on ORP feedback for intermittent airlift recirculation, in order to solve the technical problems in the prior art, such as ORP only being detected but not controlled, lack of closed-loop regulation in airlift recirculation, lack of coordinated linkage between various biochemical zones, poor system shock resistance due to a single microbial population, and lagging control and high energy consumption in the aerobic zone, thereby achieving intelligent linkage control between ORP feedback and airlift recirculation.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for treating intermittent airlift reflux wastewater based on ORP feedback, comprising the following steps: Step 1: Set up the first ORP detection instrument in the anaerobic zone to detect the ORP value of the mixed liquor in the anaerobic zone in real time. Use the air-lift sludge circulation rate as the adjustment means, and control the ORP of the anaerobic zone to change periodically within the first preset range through the anaerobic zone ORP adjustment method. Step 2: Set up a second ORP detection instrument in the anoxic zone to detect the ORP value of the mixture in the anoxic zone in real time. Use the circulation volume of the airlift digestion liquid as an adjustment means, and control the ORP of the anoxic zone to change periodically within a second preset range through the ORP adjustment method in the anoxic zone. Step 3: Install a third ORP meter at the inlet of the aerobic zone and a DO meter at the end of the aerobic zone. Use the ORP value at the inlet and the DO value at the end of the aerobic zone as coordinated control parameters, and adjust the aeration rate of the aerobic zone through the aerobic zone coordinated adjustment method to control the ORP of the aerobic zone to change periodically within the third preset range. The airlift sludge circulation and airlift digestion liquid circulation utilize compressed air injected into the riser to generate a gas-liquid density difference, achieving pump-free lifting and reflux.

[0009] A further technical solution of this application: the first preset range is -400mV to -50mV, the second preset range is -150mV to 50mV, and the third preset range is 50mV to 400mV; the ORP of each region fluctuates cyclically within its respective preset range according to a preset period of 0 to 48 hours.

[0010] A further technical solution of this application: the ORP regulation method in the anaerobic zone and / or the ORP regulation method in the anoxic zone specifically includes: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP reaches the current target value and the duration exceeds 40 minutes, the corresponding air lift return flow rate is adjusted in 10% increments to allow the ORP to transition to the next target value. When the ORP deviates from the expected direction, it is judged as an abnormal water inflow and an early warning signal is issued; After completing one preset cycle, repeat the next cycle.

[0011] A further technical solution of this application: the aerobic zone synergistic regulation method specifically includes: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP at the aerobic zone inlet reaches the current target value and lasts for more than 40 minutes, the aeration rate is adjusted in increments of 10% to allow the ORP to transition to the next target value. The DO value at the end of the aerobic zone is used as the calibration parameter for adjusting the aeration volume. When the DO value deviates from the preset range, the aeration volume is adjusted in 10% increments to correct it.

[0012] A further technical solution of this application is to issue an early warning signal when the ORP change value in the anaerobic zone exceeds 150mV, or the ORP change value in the anoxic zone exceeds 100mV, or the ORP change value in the aerobic zone exceeds 150mV.

[0013] An intermittent air-lift reflux wastewater treatment device based on ORP feedback includes: The system includes an anaerobic tank, an anoxic tank, and an aerobic tank, wherein the outlet of the anaerobic tank is connected to the inlet of the anoxic tank, and the outlet of the anoxic tank is connected to the inlet of the aerobic tank. The first ORP detection instrument is installed in the anaerobic tank, the second ORP detection instrument is installed in the anoxic tank, the third ORP detection instrument is installed at the inlet of the aerobic tank, and the DO detection instrument is installed at the upper part of the aerobic tank. An air-lift sludge return device includes a first return pipe and a first air-lift pipe. The inlet of the first return pipe is located in the aerobic tank, and the outlet is located in the anaerobic tank. One end of the first air-lift pipe is connected to a compressed air source, and the other end is inserted into the lower side of the first return pipe. A first flow control valve is also installed on the first air-lift pipe. A fourth flow control valve and a first flow meter are sequentially installed on the first return pipe. The airlift digester reflux device includes a second reflux pipe and a second airlift pipe. The inlet of the second reflux pipe is located in the aerobic tank and the outlet is located in the anoxic tank. One end of the second airlift pipe is connected to a compressed air source, and the other end is inserted obliquely upward into the lower side of the second reflux pipe. A second flow control valve is also installed on the second airlift pipe. A third flow control valve and a second flow meter are also installed sequentially on the second reflux pipe. An aeration device for the aerobic tank is installed at the bottom of the aerobic tank. The controller is connected to the first ORP detector, the second ORP detector, the third ORP detector, the DO detector, the first flow control valve, the second flow control valve, and the aeration device of the aerobic tank, respectively.

[0014] A further technical solution of this application: the anaerobic tank is also provided with an anaerobic tank inlet pipe, and the anaerobic tank is provided with a sludge circulation and sludge discharge distribution pipe, the sludge circulation and sludge discharge distribution pipe being higher than the anaerobic tank inlet pipe, and the first ORP detection instrument being installed at a distance from the bottom of the anaerobic tank. The anoxic tank is connected to an anoxic tank inlet pipe, and the anoxic tank is equipped with a digestive fluid circulation outlet distribution pipe, which is higher than the anoxic tank inlet pipe.

[0015] A further technical solution of this application: the aerobic tank is provided with a sludge circulation inlet distribution pipe and a digester circulation inlet distribution pipe, and the sludge circulation inlet distribution pipe is horizontally installed at the bottom of the aerobic tank; The aeration device for the aerobic tank is installed at a distance from the bottom of the aerobic tank.

[0016] A further technical solution of this application: the angle between the air outlet direction of the first air lift pipe and the vertical direction of the first return pipe is 45 degrees, and the angle between the air outlet direction of the second air lift pipe and the vertical direction of the second return pipe is 45 degrees.

[0017] An intermittent airlift reflux wastewater treatment system based on ORP feedback, characterized in that it includes: The system comprises an anaerobic zone, an anoxic zone, and an aerobic zone. The effluent from the anaerobic zone flows by gravity into the anoxic zone, and the effluent from the anoxic zone flows by gravity into the aerobic zone. The ORP detection unit includes a first ORP detection instrument installed in the anaerobic zone, a second ORP detection instrument installed in the anoxic zone, and a third ORP detection instrument installed at the inlet of the aerobic zone. The DO detection unit includes a DO detection instrument located at the end of the aerobic zone; The airlift reflux unit includes an airlift sludge reflux device and an airlift digester reflux device. The airlift sludge reflux device is used to reflux the mixed liquor from the aerobic zone to the anaerobic zone by airlift, and the airlift digester reflux device is used to reflux the mixed liquor from the aerobic zone to the anoxic zone by airlift. The aeration unit is located at the bottom of the aerobic zone; The control unit is connected to the ORP detection unit, DO detection unit, airlift recirculation unit and aeration unit respectively, and is configured to perform an intermittent airlift recirculation wastewater treatment method based on ORP feedback.

[0018] Compared with the prior art, the technical solution provided by this invention has the following advantages: 1. This invention utilizes airlift sludge circulation and airlift digester circulation to replace traditional circulation pumps. The pulses generated during airlift achieve mixing in the anaerobic and anoxic zones, eliminating the need for a separate underwater mixer and reducing equipment investment and maintenance costs. Simultaneously, ORP feedback control of the airlift intensity precisely controls the amount of air introduced during recirculation, preventing disruption of the anaerobic / anoxic environment and significantly reducing energy consumption. Furthermore, the ORP in each zone circulates and fluctuates within its preset range according to a pre-set cycle, actively creating a dynamic growth environment. This results in a greater variety and quantity of microbial populations in the anaerobic, anoxic, and aerobic zones, all of which remain active. When the influent contains substances requiring specific population treatment, these populations can rapidly multiply, improving the system's adaptability and resilience to varying industrial wastewater conditions.

[0019] 2. This invention utilizes real-time monitoring and closed-loop control of ORP in each zone. When significant fluctuations in water quality or quantity cause substantial changes in ORP, the system automatically adjusts the return flow or aeration rate, providing early warnings to operators, reducing impact, and quickly restoring normal operation. Adding an ORP monitoring instrument at the aerobic zone inlet, in conjunction with the DO monitoring instrument at the aerobic zone's end, allows for proactive detection of water quality and quantity changes at the aerobic zone inlet, eliminating the lag inherent in single DO control and achieving precise aeration control. Precise control of ORP in the anoxic zone accurately determines carbon source requirements, preventing premature or excessive carbon source addition and effectively conserving carbon resources. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Figure 2 This is a graph showing the ORP data of the anaerobic tank in this invention. Figure 3 This is a graph showing the ORP data of the anoxic tank in this invention. Figure 4 This is a graph showing the ORP data of the aerobic tank in this invention.

[0021] Explanation of the labels in the diagram: 1. Anaerobic tank; 2. Anoxic tank; 3. Aerobic tank; 4. First ORP monitoring instrument; 5. Second ORP monitoring instrument; 6. Third ORP monitoring instrument; 7. DO monitoring instrument; 8. First return pipe; 9. First air lift pipe; 10. First flow control valve; 11. Second return pipe; 12. Second air lift pipe; 13. Second flow control valve; 14. Aerobic tank aeration device; 15. Controller; 16. Compressed air source; 17. Anaerobic tank inlet pipe; 18. Sludge circulation outlet distribution pipe; 19. Anoxic tank liquid inlet pipe; 20. Digestering liquid circulation outlet distribution pipe; 21. Sludge circulation inlet distribution pipe; 22. Digestering liquid circulation inlet distribution pipe; 23. Inlet flow meter; 24. First flow meter; 25. Second flow meter; 26. Fourth flow control valve; 27. Third flow control valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention will be further described below with reference to the embodiments.

[0023] Example 1 Please see Figure 1 In one embodiment of this application, the wastewater treatment device of the present invention mainly includes an anaerobic tank 1, an anoxic tank 2 and an aerobic tank 3.

[0024] Anaerobic tank 1 is connected to an anaerobic tank inlet pipe 17, which is installed horizontally at a distance of 0.15±0.05m from the bottom of anaerobic tank 1. An inlet flow meter 23 is installed on the inlet pipe 17. A first ORP (Oxygen Response Rate) meter 4 is installed inside anaerobic tank 1, positioned 1.0±0.10m from the bottom of anaerobic tank 1. A sludge circulation and sludge distribution pipe 18 is also installed inside anaerobic tank 1. This pipe is installed horizontally and is 2.0±0.10m higher than the inlet pipe 17. The vertical distance between the sludge circulation and sludge distribution pipe 18 and the first ORP meter 4 is not less than 1.0±0.10m. The effluent from anaerobic tank 1 flows from the top into the inlet of anoxic tank 2.

[0025] Anoxic tank 2 is connected to an anoxic tank inlet pipe 19. A second ORP (Optical Resource Propagation) meter 5 is installed inside anoxic tank 2. Anoxic tank 2 also has a digester fluid circulation outlet distribution pipe 20, which is installed horizontally and is 1.5 ± 0.10 m higher than the anoxic tank inlet pipe 19. The outlet of the digester fluid circulation outlet distribution pipe 20 is inclined downwards at a 45-degree angle. The horizontal distance between the second ORP meter 5 and the digester fluid circulation outlet distribution pipe 20 is not less than 2.0 ± 0.10 m, and the vertical height difference is less than 0.05 m. The effluent from anoxic tank 2 flows from the bottom into the inlet of aerobic tank 3.

[0026] A third ORP (Optical Reduction) meter 6 is installed at the inlet of the aerobic tank 3, at a distance of 1.0 ± 0.10 m from the bottom of the aerobic tank 3. A DO (Dissolved Oxygen) meter 7 is installed at the upper part of the aerobic tank 3. The aerobic tank 3 contains a sludge circulation inlet distribution pipe 21 and a digestate circulation inlet distribution pipe 22. The sludge circulation inlet distribution pipe 21 is horizontally installed at a distance of 0.15 ± 0.05 m from the bottom of the aerobic tank 3, and the digestate circulation inlet distribution pipe 22 is horizontally installed with a height difference of ± 0.05 m between it and the third ORP meter 6. An aerobic tank aeration device 14 is also installed at the bottom of the aerobic tank 3, at a distance of 0.25 ± 0.05 m from the bottom of the aerobic tank 3. The height difference between the bottom of the aerobic tank aeration device 14 and the bottom of the sludge circulation inlet distribution pipe 21 is 0.10 ± 0.05 m.

[0027] The airlift sludge return device includes a first return pipe 8 and a first airlift pipe 9. The inlet of the first return pipe 8 is located in the aerobic tank 3, and the outlet is located in the anaerobic tank 1. One end of the first airlift pipe 9 is connected to a compressed air source 16, and the other end is inserted into the lower side of the first return pipe 8. A first flow control valve 10 is installed on the first airlift pipe 9, and a fourth flow control valve 26 and a first flow meter 24 are sequentially installed on the first return pipe 8.

[0028] The airlift digester reflux device includes a second reflux pipe 11 and a second airlift pipe 12. The inlet of the second reflux pipe 11 is located in the aerobic tank 3, and the outlet is located in the anoxic tank 2. One end of the second airlift pipe 12 is connected to a compressed air source 16, and the other end is inserted obliquely upwards into the lower side of the second reflux pipe 11. A second flow control valve 13 is installed on the second airlift pipe 12, and a third flow control valve 27 and a second flow meter 25 are sequentially installed on the second reflux pipe 11.

[0029] The controller 15 is connected to the first ORP detector 4, the second ORP detector 5, the third ORP detector 6, the DO detector 7, the first flow control valve 10, the second flow control valve 13, and the aeration device 14 in the aerobic tank. The controller 15 receives the detection signals from each instrument and sends control commands to each actuator according to the preset control logic.

[0030] Preferably, the angle between the outlet direction of the first air-lift pipe 9 and the perpendicular direction of the first return pipe 8 is 45 degrees, and the angle between the outlet direction of the second air-lift pipe 12 and the perpendicular direction of the second return pipe 11 is 45 degrees. This angle is beneficial to the uniform distribution of bubbles and the lifting efficiency during the air-lift process.

[0031] During operation, compressed air supplied by compressed air source 16 enters the bottom of the first return pipe 8 through the first air lift pipe 9, causing the density of the sludge-water mixture in the first return pipe 8 to decrease after mixing with air bubbles. The liquid outside the pipe pushes the mixture inside the pipe upwards along the pipe body, realizing the pump-free return of sludge from the aerobic tank 3 to the anaerobic tank 1. Similarly, compressed air enters the bottom of the second return pipe 11 through the second air lift pipe 12, realizing the pump-free return of digestate from the aerobic tank 3 to the anoxic tank 2.

[0032] Example 2 like Figures 1-4 As shown, the present invention provides an intermittent air-lift reflux wastewater treatment method based on ORP feedback, comprising the following steps: Step 1: Set up the first ORP detection instrument in the anaerobic zone to detect the ORP value of the mixed liquor in the anaerobic zone in real time. Use the air-lift sludge circulation rate as the adjustment means, and control the ORP of the anaerobic zone to change periodically within the first preset range through the anaerobic zone ORP adjustment method. Step 2: Set up a second ORP detection instrument in the anoxic zone to detect the ORP value of the mixture in the anoxic zone in real time. Use the circulation volume of the airlift digestion liquid as an adjustment means, and control the ORP of the anoxic zone to change periodically within a second preset range through the ORP adjustment method in the anoxic zone. Step 3: Install a third ORP meter at the inlet of the aerobic zone and a DO meter at the end of the aerobic zone. Use the ORP value at the inlet and the DO value at the end of the aerobic zone as coordinated control parameters, and adjust the aeration rate of the aerobic zone through the aerobic zone coordinated adjustment method to control the ORP of the aerobic zone to change periodically within the third preset range. The airlift sludge circulation and airlift digestion liquid circulation utilize compressed air injected into the riser to generate a gas-liquid density difference, achieving pump-free lifting and reflux.

[0033] Furthermore, the first preset range is -400mV to -50mV, the second preset range is -150mV to 50mV, and the third preset range is 50mV to 400mV; the ORP of each region fluctuates cyclically within its respective preset range according to a preset period of 0 to 48 hours.

[0034] Furthermore, the ORP regulation method in the anaerobic zone and / or the ORP regulation method in the hypoxic zone specifically includes: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP reaches the current target value and the duration exceeds 40 minutes, the corresponding air lift return flow rate is adjusted in 10% increments to allow the ORP to transition to the next target value. When the ORP deviates from the expected direction, it is judged as an abnormal water inflow and an early warning signal is issued; After completing one preset cycle, repeat the next cycle.

[0035] Furthermore, the aerobic zone coordinated regulation method specifically includes: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP at the aerobic zone inlet reaches the current target value and lasts for more than 40 minutes, the aeration rate is adjusted in increments of 10% to allow the ORP to transition to the next target value. The DO value at the end of the aerobic zone is used as the calibration parameter for adjusting the aeration volume. When the DO value deviates from the preset range, the aeration volume is adjusted in 10% increments to correct it.

[0036] Furthermore, an early warning signal is issued when the ORP change value in the anaerobic zone exceeds 150mV, or the ORP change value in the hypoxic zone exceeds 100mV, or the ORP change value in the aerobic zone exceeds 150mV.

[0037] Specifically, the ORP adjustment method in the anaerobic zone is as follows: the main function of the anaerobic zone is for phosphorus release by polyphosphate-accumulating bacteria. The first preset range is -400mV to -50mV, and the preset cycle is 0 to 48 hours.

[0038] In this embodiment, a preset period of 48 hours is used as an example for explanation. Within each preset period, multiple target ORP values ​​are set in ascending order, with the specific target value sequence being: -200mV→-300mV→-400mV→-300mV→-200mV→-100mV→-50mV→-100mV→-200mV.

[0039] In the first stage, starting from 0 to 6 hours, at the initial stage of the cycle, the target value of ORP in the anaerobic zone is controlled to be -200mV, at which time the air-lift sludge circulation volume is zero or small.

[0040] In the second phase, lasting 7–12 hours, if the measured ORP continues to decrease from -200mV to below -300mV and this decrease persists for more than 40 minutes, the system will make the following judgment: Determine if the ORP in the anaerobic zone has fallen below -300mV in the past 48 hours: If not, then maintain the current airlift sludge circulation volume unchanged; If so, further determine whether the current ORP value in the aerobic zone is greater than -300mV and lasts for more than 40 minutes; If not, increase the air-lift sludge circulation volume by 10%; If so, then maintain the current airlift sludge circulation volume unchanged.

[0041] In the third stage, from 13 to 18 hours, if the measured ORP continues to decrease to -400mV and lasts for more than 40 minutes, increase the air-lift sludge circulation rate by 10%. Afterward, check the ORP every 5 minutes. If the average ORP value after 5 minutes is still below -400mV, continue to increase the air-lift sludge circulation rate by 10%, repeating this process until the average ORP value rises back above -300mV. At this point, maintain the current air-lift sludge circulation rate unchanged.

[0042] In the fourth stage, from 19 to 24 hours, when the measured ORP rises to -300mV and lasts for more than 40 minutes, the air-lift sludge circulation rate is increased by 10%. Afterward, ORP is measured every 5 minutes. If the average ORP value over 5 minutes is higher than -300mV, the air-lift sludge circulation rate is increased by another 10%, and this process is repeated until the average ORP value rises to -200mV.

[0043] In the fifth stage, after 25–28 hours, when the measured ORP rises to -200mV and lasts for more than 40 minutes, the air-lift sludge circulation rate is increased by 10%. Afterward, ORP is measured every 5 minutes. If the average ORP value over 5 minutes is higher than -200mV, the air-lift sludge circulation rate is increased by another 10%, and this process is repeated until the average ORP value rises to -100mV.

[0044] In the sixth stage, from 29 to 36 hours, when the measured ORP rises to -100mV and lasts for more than 40 minutes, the air-lift sludge circulation rate is increased by 10%. Afterward, ORP is measured every 5 minutes. If the average ORP value over 5 minutes is higher than -100mV, the air-lift sludge circulation rate is increased by another 10%, and this process is repeated until the average ORP value rises to -50mV.

[0045] In the seventh stage, 37–42 hours, the measured ORP reaches -50mV. If the duration exceeds 40 minutes, the current air-lift sludge circulation volume remains unchanged; otherwise, reduce the air-lift sludge circulation volume by 10% until the ORP drops to -100mV.

[0046] In the eighth stage, 43-48 hours, the measured ORP reaches -100mV. If the duration exceeds 40 minutes, the current air-lift sludge circulation volume remains unchanged; otherwise, the air-lift sludge circulation volume is reduced by 10% until the ORP drops to -200mV.

[0047] After completing the above eight stages, repeat the adjustment and control process of stage one to achieve periodic fluctuations of ORP in the anaerobic zone within the range of -400mV to -50mV.

[0048] During the entire adjustment process, when the measured ORP deviates from the expected direction (for example, it decreases instead of increasing during the phase that should increase, or increases instead of decreasing during the phase that should decrease), it is judged as an abnormal water intake and an early warning signal is issued.

[0049] Example 3 The ORP adjustment method in the anoxic zone is used because the main function of the anoxic zone is to provide a nitrogen-removing environment for denitrifying bacteria. The second preset range is -150mV to 50mV, and the preset cycle is 0 to 48 hours.

[0050] In this embodiment, a preset period of 48 hours is used as an example for explanation. Within each preset period, multiple progressively increasing target ORP values ​​are set; The specific target value sequence is: -100mV→-150mV→-100mV→-50mV→0mV→50mV→0mV→-50mV→-100mV.

[0051] Phase 1 (0-6 hours): In the initial stage of the cycle, the target value of ORP in the hypoxic zone is controlled to be -100mV, at which time the circulation volume of the airlift digestion liquid is zero or small.

[0052] Phase 2 (7–12 hours): When the measured ORP continues to decrease from -100mV to below -150mV and this decrease lasts for more than 40 minutes, the system makes the following judgment: Determine if the ORP in the hypoxic area has fallen below -150mV within the past 48 hours: If not, then maintain the current airlift digestion fluid circulation volume unchanged; If so, further determine whether the current ORP value in the aerobic zone is greater than -150mV and lasts for more than 40 minutes; If not, increase the circulation volume of the airlift digestion solution by 10%; If so, then maintain the current airlift digestion fluid circulation volume unchanged.

[0053] Phase 3 (13–18 hours): When the measured ORP rises from -150 mV to -100 mV and lasts for more than 40 minutes, the circulation volume of the airlift digestion solution is increased by 10%. ORP is then measured every 5 minutes. If the average ORP value after 5 minutes is still above -100 mV, the circulation volume of the airlift digestion solution is increased by another 10%, and this process is repeated until the average ORP value drops to -50 mV.

[0054] Phase 4 (19–24 hours): When the measured ORP reaches -50 mV and lasts for more than 40 minutes, increase the circulation volume of the airlift digestion solution by 10%. Thereafter, measure the ORP every 5 minutes. If the average ORP value over 5 minutes is higher than -50 mV, continue to increase the circulation volume of the airlift digestion solution by 10%, and repeat this process until the average ORP value rises to 0 mV.

[0055] Phase 5 (25-30 hours): When the measured ORP reaches 0 mV and lasts for more than 40 minutes, increase the circulation volume of the airlift digestion solution by 10%. Thereafter, measure the ORP every 5 minutes. If the average ORP value over 5 minutes is higher than 0 mV, continue to increase the circulation volume of the airlift digestion solution by 10%, and repeat this process until the average ORP value rises to 50 mV.

[0056] Phase 6 (31–36 hours): When the measured ORP reaches 50 mV and lasts for more than 40 minutes, reduce the circulation volume of the airlift digestion solution by 10%. Thereafter, measure the ORP every 5 minutes. If the average ORP value is still higher than 50 mV after 5 minutes, continue to reduce the circulation volume of the airlift digestion solution by 10%, and repeat this process until the average ORP value drops to 0 mV.

[0057] Phase 7 (37-42 hours): The measured ORP reaches 0mV. If the duration exceeds 40 minutes, the current airlift digestion fluid circulation volume remains unchanged; otherwise, reduce the airlift digestion fluid circulation volume by 10% until the ORP drops to -50mV.

[0058] Eighth stage (43-48 hours): The measured ORP reaches -50mV. If the duration exceeds 40 minutes, the current airlift digestion fluid circulation volume remains unchanged; otherwise, reduce the airlift digestion fluid circulation volume by 10% until the ORP drops to -100mV.

[0059] After completing the above eight stages, repeat the adjustment and control process of stage one to achieve periodic fluctuations of ORP in the hypoxic zone within the range of -150mV to 50mV.

[0060] During the entire adjustment process, when the measured ORP deviates from the expected direction, it is judged as an abnormal water intake and an early warning signal is issued.

[0061] Example 4 The aerobic zone is a synergistic regulation method, where the aerobic zone is the main site for nitrogen and phosphorus removal by microorganisms. The third preset range is 50mV~400mV, and the preset cycle is 0~48 hours.

[0062] In this embodiment, a preset period of 48 hours is used as an example for explanation. Within each preset period, multiple progressively increasing target ORP values ​​are set; The specific target value sequence is: 200mV→100mV→50mV→100mV→200mV→300mV→400mV→300mV→200mV.

[0063] The aeration rate of the aeration device 14 in the aerobic tank is adjusted by using the measured value of the third ORP detector 6 at the inlet of the aerobic zone as the main control basis and the measured value of the DO detector 7 at the end of the aerobic zone as the calibration parameter.

[0064] Phase 1 (0-6 hours): At the beginning of the cycle, the target value of ORP in the aerobic zone is controlled at 200mV, and the aeration volume is reduced by 5%.

[0065] Second stage (7-12 hours): When the measured ORP drops from 200mV to below 100mV for more than 40 minutes, the aeration volume decreases by 5%.

[0066] Phase 3 (13-18 hours): If the measured ORP continues to decrease to 50mV and lasts for more than 40 minutes, reduce the aeration rate by 5%. Then, check the ORP every 5 minutes. If the average ORP value is still below 50mV after 5 minutes, continue to reduce the aeration rate by 5%, and repeat this process until the average ORP value rises back to 100mV.

[0067] Phase 4 (19–24 hours): When the measured ORP rises from 50 mV to 100 mV and lasts for more than 40 minutes, increase the aeration rate by 5%. Then, measure the ORP every 5 minutes. If the average ORP value over 5 minutes is higher than 100 mV, continue to increase the aeration rate by 5%, and repeat this process until the average ORP value rises to 200 mV.

[0068] Phase 5 (25-30 hours): When the measured ORP rises from 100mV to 200mV and lasts for more than 40 minutes, increase the aeration rate by 5%. Then, check the ORP every 5 minutes. If the average ORP value over 5 minutes is higher than 200mV, continue to increase the aeration rate by 5%, and repeat this process until the average ORP value rises to 300mV.

[0069] Phase 6 (31–36 hours): When the measured ORP rises from 200 mV to 300 mV and lasts for more than 40 minutes, increase the aeration rate by 5%. Thereafter, measure the ORP every 5 minutes. If the average ORP value over 5 minutes is higher than 300 mV, continue to increase the aeration rate by 5%, and repeat this process until the average ORP value rises to 400 mV.

[0070] Phase 7 (37-42 hours): If the measured ORP reaches 400mV and the duration exceeds 40 minutes, maintain the current aeration rate; otherwise, reduce the aeration rate by 5% until the ORP drops to 300mV.

[0071] Phase 8 (43-48 hours): If the measured ORP reaches 300mV and the duration exceeds 40 minutes, reduce the aeration rate by 5%; otherwise, keep the current aeration rate unchanged until the ORP drops to 200mV.

[0072] After completing the above eight stages, repeat the adjustment and control process of stage one to achieve periodic fluctuations of ORP in the aerobic zone within the range of 50mV to 400mV.

[0073] During the coordinated regulation process in the aerobic zone, the detection value of DO meter 7 at the end of the aerobic zone is used as the calibration parameter for aeration rate adjustment. When the DO value deviates from the preset range, the aeration rate is adjusted in 5% increments to correct the deviation, ensuring that the dissolved oxygen in the aerobic tank always meets the requirements of the biochemical reaction.

[0074] During the entire adjustment process, when the measured ORP deviates from the expected direction, it is judged as an abnormal water intake and an early warning signal is issued.

[0075] Example 5 In the control method of the present invention, the triggering of the warning signal includes, but is not limited to, the following two situations: As described in Examples 2 to 4, when the ORP of each zone deviates from the expected direction (for example, it decreases instead of increasing during the phase that should increase, or increases instead of decreasing during the phase that should decrease), it is judged as an abnormal water intake and an early warning signal is issued.

[0076] If the ORP change value in the anaerobic zone exceeds 150mV, or the ORP change value in the anoxic zone exceeds 100mV, or the ORP change value in the aerobic zone exceeds 150mV, the controller 15 will issue an early warning signal to prompt the operators to check the influent water quality or operating conditions and promptly eliminate any abnormalities.

[0077] The two warning scenarios mentioned above are independent of each other and exist in parallel. A warning will be triggered when either scenario is met.

[0078] Example 6 The present invention also provides an intermittent airlift reflux wastewater treatment system based on ORP feedback, comprising an anaerobic zone, an anoxic zone and an aerobic zone, wherein the effluent from the anaerobic zone flows by gravity into the anoxic zone, and the effluent from the anoxic zone flows by gravity into the aerobic zone.

[0079] The system includes an ORP detection unit, a DO detection unit, an airlift reflux unit, an aeration unit, and a control unit.

[0080] The ORP detection unit includes a first ORP detector 4 located in the anaerobic zone, a second ORP detector 5 located in the anoxic zone, and a third ORP detector 6 located at the inlet of the aerobic zone.

[0081] The DO detection unit includes a DO detection instrument 7 located at the end of the aerobic zone.

[0082] The airlift reflux unit includes an airlift sludge reflux device 8 and an airlift digester reflux device 12. The airlift sludge reflux device is used to reflux the mixed liquor from the aerobic zone to the anaerobic zone by airlift, and the airlift digester reflux device is used to reflux the mixed liquor from the aerobic zone to the anoxic zone by airlift.

[0083] The aeration unit includes an aeration device 14 for the aerobic pool located at the bottom of the aerobic zone.

[0084] The control unit includes a controller 15, which is connected to the ORP detection unit, the DO detection unit, the airlift reflux unit, and the aeration unit via signals. The controller 15 is configured to perform the method described in any one of claims 1 to 5.

[0085] During system operation, the controller 15 receives detection signals from the first ORP detector 4, the second ORP detector 5, the third ORP detector 6, and the DO detector 7 in real time. According to the preset control logic, it sends control commands to the first flow control valve 10, the second flow control valve 13, and the aerobic tank aeration device 14 to adjust the airlift sludge circulation volume, the airlift digester circulation volume, and the aeration volume of the aerobic tank, so as to realize the periodic fluctuation of ORP in each zone within their respective preset ranges.

[0086] When the system detects an abnormal water inflow, the controller 15 issues an early warning signal to prompt operators to intervene in a timely manner.

[0087] This system is suitable for industrial wastewater treatment scenarios with varying water quality. Through the linkage control of ORP feedback and air stripping reflux, it realizes the intelligent operation of the biochemical treatment system.

[0088] In summary, this invention utilizes airlift sludge circulation and airlift digester circulation to replace traditional circulation pumps. The pulses generated during airlift achieve mixing in the anaerobic and anoxic zones, eliminating the need for a separate underwater mixer and reducing equipment investment and maintenance costs. Simultaneously, ORP feedback control of the airlift intensity precisely controls the amount of air introduced during recirculation, preventing disruption of the anaerobic or anoxic environment and significantly reducing energy consumption. Furthermore, the ORP in each zone circulates and fluctuates within its preset range according to a pre-set cycle, actively creating a dynamic growth environment. This results in a greater variety and quantity of microbial populations in the anaerobic, anoxic, and aerobic zones, all of which remain active. When the influent contains substances requiring specific population treatment, these populations can rapidly multiply, enhancing the system's adaptability and resilience to varying industrial wastewater conditions.

[0089] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

[0090] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for treating wastewater by intermittent airlift recirculation based on ORP feedback, characterized in that, Includes the following steps: Step 1: Set up the first ORP detection instrument in the anaerobic zone to detect the ORP value of the mixed liquor in the anaerobic zone in real time. Use the air-lift sludge circulation rate as the adjustment means, and control the ORP of the anaerobic zone to change periodically within the first preset range through the anaerobic zone ORP adjustment method. Step 2: Set up a second ORP detection instrument in the anoxic zone to detect the ORP value of the mixture in the anoxic zone in real time. Use the circulation volume of the airlift digestion liquid as an adjustment means, and control the ORP of the anoxic zone to change periodically within a second preset range through the ORP adjustment method in the anoxic zone. Step 3: Install a third ORP meter at the inlet of the aerobic zone and a DO meter at the end of the aerobic zone. Use the ORP value at the inlet and the DO value at the end of the aerobic zone as coordinated control parameters, and adjust the aeration rate of the aerobic zone through the aerobic zone coordinated adjustment method to control the ORP of the aerobic zone to change periodically within the third preset range. The airlift sludge circulation and airlift digestion liquid circulation utilize compressed air injected into the riser to generate a gas-liquid density difference, achieving pump-free lifting and reflux.

2. The intermittent airlift reflux wastewater treatment method based on ORP feedback according to claim 1, characterized in that, The first preset range is -400mV to -50mV, the second preset range is -150mV to 50mV, and the third preset range is 50mV to 400mV; the ORP of each region fluctuates cyclically within its respective preset range according to a preset period of 0 to 48 hours.

3. The intermittent airlift reflux wastewater treatment method based on ORP feedback according to claim 2, characterized in that, The ORP regulation methods for anaerobic zones and / or hypoxic zones specifically include: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP reaches the current target value and the duration exceeds 40 minutes, the corresponding air lift return flow rate is adjusted in 10% increments to allow the ORP to transition to the next target value. When the ORP deviates from the expected direction, it is judged as an abnormal water inflow and an early warning signal is issued; After completing one preset cycle, repeat the next cycle.

4. The intermittent airlift reflux wastewater treatment method based on ORP feedback according to claim 2, characterized in that, The aerobic zone coordinated regulation method specifically includes: Within each preset cycle, multiple progressively increasing target ORP values ​​are set. When the measured ORP at the aerobic zone inlet reaches the current target value and lasts for more than 40 minutes, the aeration rate is adjusted in increments of 5% to allow the ORP to transition to the next target value. The DO value at the end of the aerobic zone is used as the calibration parameter for adjusting the aeration volume. When the DO value deviates from the preset range, the aeration volume is adjusted in 10% increments to correct it.

5. The intermittent airlift reflux wastewater treatment method based on ORP feedback according to claim 3, characterized in that, An early warning signal is issued when the ORP change value in the anaerobic zone exceeds 150mV, or the ORP change value in the hypoxic zone exceeds 100mV, or the ORP change value in the aerobic zone exceeds 150mV.

6. A wastewater treatment device based on ORP feedback for implementing the method of any one of claims 1 to 5, characterized in that, include: Anaerobic tank (1), anoxic tank (2) and aerobic tank (3), wherein the outlet of the anaerobic tank (1) is connected to the inlet of the anoxic tank (2), and the outlet of the anoxic tank (2) is connected to the inlet of the aerobic tank (3). The first ORP detection instrument (4) is installed in the anaerobic tank (1), the second ORP detection instrument (5) is installed in the anoxic tank (2), and the third ORP detection instrument (6) is installed at the inlet of the aerobic tank (3). and the DO detection instrument (7) installed at the upper end of the aerobic tank (3); The air-lift sludge return device includes a first return pipe (8) and a first air-lift pipe (9). The inlet of the first return pipe (8) is located in the aerobic tank (3), and the outlet is located in the anaerobic tank (1). One end of the first air-lift pipe (9) is connected to a compressed air source (16), and the other end is inserted into the lower side of the first return pipe (8). A first flow control valve (10) is also installed on the first air-lift pipe (9). A fourth flow control valve (26) and a first flow meter (24) are installed sequentially on the first return pipe (8). The airlift digester reflux device includes a second reflux pipe (11) and a second airlift pipe (12). The inlet of the second reflux pipe (11) is located in the aerobic tank (3) and the outlet is located in the anoxic tank (2). One end of the second airlift pipe (12) is connected to a compressed air source (16), and the other end is inserted obliquely upward into the lower side of the second reflux pipe (11). A second flow control valve (13) is also installed on the second airlift pipe (12). A third flow control valve (27) and a second flow meter (25) are also installed sequentially on the second reflux pipe (11). An aeration device (14) for the aerobic tank is installed at the bottom of the aerobic tank (3); The controller (15) is connected to the first ORP detector (4), the second ORP detector (5), the third ORP detector (6), the DO detector (7), the first flow control valve (10), the second flow control valve (13), and the aerobic tank aeration device (14), respectively.

7. The intermittent airlift reflux wastewater treatment device based on ORP feedback according to claim 6, characterized in that, The anaerobic tank (1) is also equipped with an anaerobic tank inlet pipe (17), and the anaerobic tank (1) is equipped with a sludge circulation and sludge discharge distribution pipe (18). The sludge circulation and sludge discharge distribution pipe (18) is higher than the anaerobic tank inlet pipe (17). The first ORP detection instrument (4) is installed at a distance from the bottom of the anaerobic tank (1). The anoxic pool (2) is connected to an anoxic pool inlet pipe (19), and the anoxic pool (2) is provided with a digestive fluid circulation outlet distribution pipe (20), which is higher than the anoxic pool inlet pipe (19).

8. The intermittent airlift reflux wastewater treatment device based on ORP feedback according to claim 6, characterized in that, The aerobic tank (3) is provided with a sludge circulation inlet distribution pipe (21) and a digester circulation inlet distribution pipe (22), and the sludge circulation inlet distribution pipe (21) is installed horizontally at the bottom of the aerobic tank (3); The aeration device (14) of the aerobic pool is installed at a distance from the bottom of the aerobic pool (3).

9. The intermittent airlift reflux wastewater treatment device based on ORP feedback according to claim 6, characterized in that, The air outlet direction of the first air lift pipe (9) forms an angle of 45 degrees with the vertical direction of the first return pipe (8), and the air outlet direction of the second air lift pipe (12) forms an angle of 45 degrees with the vertical direction of the second return pipe (11).

10. An intermittent airlift recirculation wastewater treatment system based on ORP feedback, characterized in that, include: The system comprises an anaerobic zone, an anoxic zone, and an aerobic zone. The effluent from the anaerobic zone flows by gravity into the anoxic zone, and the effluent from the anoxic zone flows by gravity into the aerobic zone. The ORP detection unit includes a first ORP detection instrument installed in the anaerobic zone, a second ORP detection instrument installed in the anoxic zone, and a third ORP detection instrument installed at the inlet of the aerobic zone. The DO detection unit includes a DO detection instrument located at the end of the aerobic zone; The airlift reflux unit includes an airlift sludge reflux device and an airlift digester reflux device. The airlift sludge reflux device is used to reflux the mixed liquor from the aerobic zone to the anaerobic zone by airlift, and the airlift digester reflux device is used to reflux the mixed liquor from the aerobic zone to the anoxic zone by airlift. The aeration unit is located at the bottom of the aerobic zone; The control unit is connected to the ORP detection unit, DO detection unit, airlift reflux unit and aeration unit respectively, and the control unit is configured to perform the method according to any one of claims 1 to 5.

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