Anaerobic-aerobic-anoxic process combined control method and device and storage medium

Abstract

The application provides an anaerobic-aerobic-anoxic process combined control method and device and a storage medium. The method comprises the following steps: estimating the internal carbon source reserve amount by an internal carbon source reserve estimation model according to the platform period length, influent organic matter concentration and water temperature at the end of the anaerobic stage; calculating the denitrification potential index by a denitrification potential prediction model according to the internal carbon source reserve amount, the nitrate nitrogen concentration at the end of the aerobic stage and the influent carbon-nitrogen ratio at the end of the aerobic stage, and generating the target operation length of the anoxic stage; collecting the oxidation-reduction potential and the nitrate nitrogen concentration in real time during the operation of the anoxic stage, and identifying the denitrification endpoint according to the variation characteristics of the two; ending the current anoxic stage as soon as the endpoint is identified, and triggering an alarm, recording the deviation and correcting the parameters of the model if the endpoint is not identified. The application is based on the metabolic mechanism of internal carbon source driven denitrification, and a combined control architecture combining feedforward prediction and real-time closed loop is constructed, which significantly improves the denitrification efficiency and operation stability of the anaerobic-aerobic-anoxic process.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more particularly to a method, apparatus, system, and storage medium for the combined control of anaerobic, aerobic, and anoxic processes. Background Technology

[0002] In recent years, with the continuous improvement of urban sewage discharge standards and the increasingly urgent need for energy conservation and emission reduction in sewage treatment, the anaerobic-aerobic-anoxic (AOA) process has received widespread attention as a novel biological nitrogen removal process. The AOA process achieves deep nitrogen removal without the need for external carbon sources through a metabolic chain: the anaerobic stage stores internal carbon sources, the aerobic stage moderately retains internal carbon sources, and the anoxic stage utilizes internal carbon sources for endogenous denitrification. It is particularly suitable for treating the low carbon-to-nitrogen ratio problem commonly found in urban sewage in my country, and has advantages such as low operating costs and stable nitrogen removal performance.

[0003] However, existing control schemes for anaerobic-aerobic-anoxic processes still have the following technical problems in practical engineering applications: Firstly, the amount of internal carbon source reserves directly determines the denitrification capacity of the anoxic section. However, the internal carbon source cannot be directly measured by existing online sensors. Existing solutions often ignore the dynamic changes of the internal carbon source or make a rough judgment based only on the concentration of organic matter in the influent, resulting in large estimation errors. This leads to excessive consumption or insufficient reserves of internal carbon source in the aerobic section, affecting the denitrification effect in the anoxic section and causing the total nitrogen in the effluent to exceed the standard. Secondly, the current schemes mostly use fixed values ​​for the duration of the anoxic section, without dynamically adjusting it according to the actual denitrification capacity of the system. When the influent water quality, water temperature and other operating conditions fluctuate, incomplete denitrification or redundant operating time may occur, making it difficult to balance the denitrification effect and operating energy consumption. Third, the existing methods for identifying the denitrification endpoint are relatively simple, relying mainly on nitrate nitrogen concentration monitoring. This is easily affected by water quality fluctuations and sensor noise, resulting in delayed identification and failure to end the anoxic phase in a timely manner, further exacerbating energy waste or incomplete denitrification. Fourth, the control logic of existing solutions often simply adopts the control modes of other biological denitrification processes, failing to align with the core mechanism of carbon source-driven denitrification within anaerobic, aerobic, and anoxic processes. Furthermore, they lack the ability to adaptively correct model parameters, resulting in a significant decrease in control accuracy and poor adaptability when operating conditions fluctuate.

[0004] Therefore, a new solution is needed. Summary of the Invention

[0005] This invention provides a method, device, and storage medium for the combined control of anaerobic, aerobic, and anoxic processes, which addresses the shortcomings of existing technologies such as the inability to estimate internal carbon sources online, fixed duration of the anoxic period, delayed identification of the denitrification endpoint, and disconnect between control logic and process mechanism.

[0006] According to a first aspect of the present invention, a method for combined control of anaerobic, aerobic, and hypoxic processes is provided, the method comprising: Step S1: During the operation of the anaerobic section, collect the oxidation-reduction potential signal and determine the duration of the plateau period based on the plateau period formed in the preset negative potential range of the oxidation-reduction potential curve. Step S2: At the end of the anaerobic phase, based on the duration of the plateau period, the concentration of organic matter in the influent, and the water temperature, estimate the amount of carbon source reserves in the system using the internal carbon source reserve estimation model. Step S3: At the end of the aerobic stage, based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, calculate the denitrification potential index using the denitrification potential prediction model, and generate the target operating time of the anoxic stage based on the denitrification potential index. Step S4: During the operation of the anoxic section, collect the redox potential signal and nitrate nitrogen concentration signal in real time, and identify the denitrification endpoint based on the characteristics of the redox potential change and the characteristics of the nitrate nitrogen concentration change. Step S5: When the denitrification endpoint is detected, the current anoxic section operation ends and the next process cycle begins; Step S6: When the anoxic section has run for the target running time and the denitrification endpoint has not been identified, an alarm is triggered and deviation data is recorded. Based on the deviation data, the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model are corrected.

[0007] In a preferred embodiment of the present invention, the plateau period is a stable segment formed by the redox potential curve within a preset negative potential range, and the stable segment satisfies that the redox potential fluctuation does not exceed a preset fluctuation threshold within a preset number of consecutive sampling periods.

[0008] In a preferred embodiment of the present invention, the internal carbon source reserve estimation model is established based on the plateau period duration, influent organic matter concentration, and water temperature, and the internal carbon source reserve is positively correlated with the plateau period duration and the influent organic matter concentration.

[0009] In a preferred embodiment of the present invention, the expression of the denitrification potential prediction model is: Where P is the denitrification potential index, This refers to the nitrate nitrogen concentration at the end of the aerobic section. This is a correction factor for operating conditions that varies with water temperature and influent carbon-nitrogen ratio; This is a correction constant used to compensate for errors in online nitrate nitrogen detection.

[0010] In a preferred embodiment of the present invention, the target running time of the anoxic segment is equal to the product of the baseline anoxic duration and the potential adjustment function, wherein the potential adjustment function is a monotonically decreasing function of the denitrification potential index.

[0011] In a preferred embodiment of the present invention, identifying the denitrification endpoint based on the redox potential change characteristics and the nitrate nitrogen concentration change characteristics includes: determining that the denitrification endpoint has been reached when the redox potential change rate is less than a preset change rate threshold and / or the nitrate nitrogen concentration is lower than a preset concentration threshold within a preset number of consecutive sampling periods.

[0012] In a preferred embodiment of the present invention, when the internal carbon source reserve is lower than a preset reserve threshold or the plateau period duration is less than a first duration threshold, a carbon source reserve warning is triggered and at least one of the following control actions is executed: reducing the aeration intensity of the aerobic section; reducing the dissolved oxygen concentration set value of the aerobic section; adjusting the influent distribution method; and extending the hydraulic retention time of the anaerobic section.

[0013] In a preferred embodiment of the present invention, the method further includes: real-time monitoring of the concentration of suspended solids in the mixed liquor, the sludge settling ratio, and the ammonia nitrogen removal rate; when the concentration of suspended solids in the mixed liquor is higher than a preset upper limit, the sludge settling ratio is higher than a preset upper limit, and the ammonia nitrogen removal rate decreases from the benchmark value by more than a preset range, the sludge discharge action at the end of the aerobic section is triggered, and the sludge discharge time is dynamically adjusted according to the change in sludge concentration.

[0014] According to a second aspect of the present invention, a combined control device for anaerobic-aerobic-anoxic processes is also provided for implementing the method described above, comprising an internal carbon source reserve estimation module, a denitrification potential prediction module, an endpoint identification and correction module, and a control system, wherein the internal carbon source reserve estimation module includes a plateau period identification unit and an internal carbon source estimation unit, and the endpoint identification and correction module includes an endpoint identification unit and a model correction unit. The plateau phase identification unit is used to collect oxidation-reduction potential signals during the operation of the anaerobic section and determine the plateau phase duration based on the plateau phase formed in the preset negative potential range of the oxidation-reduction potential curve. The internal carbon source estimation unit is used to estimate the amount of internal carbon source reserves in the system at the end of the anaerobic phase, based on the duration of the plateau period, the concentration of organic matter in the influent, and the water temperature, using an internal carbon source reserve estimation model. The denitrification potential prediction module is used to calculate the denitrification potential index at the end of the aerobic stage based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, and to generate the target operating time of the anoxic stage based on the denitrification potential index. The endpoint identification unit is used to collect redox potential signals and nitrate nitrogen concentration signals in real time during the anoxic section operation, and to identify the denitrification endpoint based on the characteristics of redox potential changes and nitrate nitrogen concentration changes. The control system is used to terminate the current anoxic section and enter the next process cycle when the denitrification endpoint is detected. The model correction unit is used to trigger an alarm and record deviation data when the denitrification endpoint is not identified after the target running time in the anoxic section, and to correct the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model based on the deviation data.

[0015] According to a third aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, it implements the steps of the combined control method for anaerobic-aerobic-anoxic processes as described above.

[0016] The anaerobic-aerobic-anoxic process joint control method, device, and storage medium of this invention have the following beneficial effects: This invention takes the metabolic chain of storing internal carbon sources in the anaerobic stage, retaining internal carbon sources in the aerobic stage, and endogenous denitrification in the anoxic stage as the main control line. Through an indirect estimation mechanism of internal carbon source reserves based on the redox potential plateau period, a feedforward prediction mechanism of denitrification potential based on internal carbon source reserves and nitrate nitrogen load, a denitrification endpoint identification mechanism based on the dual characteristics of redox potential and nitrate nitrogen, and an adaptive correction mechanism of model parameters based on operating deviation, a joint control architecture combining feedforward prediction and real-time closed-loop is constructed. This scheme solves the problem that internal carbon sources cannot be directly measured online, realizes on-demand dynamic adjustment of the operating time of the anoxic stage, improves the accuracy and timeliness of denitrification endpoint identification, and enables the entire control system to maintain stable control accuracy under different water quality and water temperature conditions, significantly improving the denitrification efficiency, operational stability, and energy-saving effect of the anaerobic-aerobic-anoxic process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort: Figure 1 This is a schematic flowchart of the combined control method for anaerobic, aerobic, and hypoxic processes provided by the present invention. Figure 2 This invention provides a schematic diagram of the oxidation-reduction potential curve and plateau phase of the anaerobic zone. Figure 3 This is a schematic diagram of the denitrification endpoint identification in the anoxic zone provided by the present invention; Figure 4 This is a schematic diagram of the structure of the combined anaerobic-aerobic-anoxic process control device provided by the present invention; Figure 5 This is a schematic diagram of the physical structure of the electronic device provided by the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] Existing control technologies for anaerobic-aerobic-anoxic processes generally suffer from problems such as the inability to measure internal carbon sources online, fixed anoxic phase duration, delayed identification of denitrification endpoints, and a disconnect between control logic and process mechanisms. Internal carbon sources are synthesized and stored by functional microorganisms using influent organic matter in the anaerobic phase, and their reserves directly determine the endogenous denitrification capacity in the anoxic phase. However, limited by online detection methods, existing solutions often ignore their dynamic changes or rely solely on a rough assessment based on influent organic matter concentration, leading to large estimation errors. Furthermore, the anoxic phase duration is often fixed and not dynamically adjusted based on the system's actual denitrification potential. In addition, the denitrification endpoint is often identified solely by nitrate nitrogen concentration, which is easily affected by water quality fluctuations and sensor noise, resulting in delays or misjudgments. These shortcomings are particularly pronounced under complex operating conditions such as low carbon-to-nitrogen ratios and low water temperatures, hindering the application and promotion of anaerobic-aerobic-anoxic processes.

[0020] To address the aforementioned problems, this invention proposes a joint control method for anaerobic, aerobic, and anoxic processes. This method first estimates the carbon source reserve within the system during the plateau period of the redox potential curve in the anaerobic stage; then, at the end of the aerobic stage, it predicts the denitrification potential based on the internal carbon source reserve and nitrate nitrogen load, and generates the target operating time for the anoxic stage accordingly; next, in the anoxic stage, it identifies the denitrification endpoint based on the dual characteristics of redox potential and nitrate nitrogen, and terminates the anoxic stage operation accordingly; finally, it adaptively corrects the model parameters based on the operating deviation.

[0021] The method provided in this invention firstly estimates the internal carbon source reserve through an oxidation-reduction potential platform, solving the problem that the internal carbon source cannot be directly measured online, and providing a key state quantity for subsequent control. Secondly, by using feedforward prediction based on the internal carbon source reserve and nitrate nitrogen load, the duration of the anoxic period is transformed from a fixed setting to dynamic allocation on demand, avoiding energy waste or incomplete denitrification caused by a fixed duration. Thirdly, by jointly identifying the denitrification endpoint using both oxidation-reduction potential and nitrate nitrogen characteristics, the method overcomes the problem of lag and misjudgment caused by single indicators being affected by water quality fluctuations and noise, improving the accuracy and timeliness of endpoint identification. Finally, by adaptively correcting the model parameters through operational deviations, the control system continuously self-calibrates as operating conditions change, ensuring long-term control accuracy.

[0022] In summary, the method provided in this embodiment of the invention significantly improves the denitrification efficiency and operational stability of anaerobic-aerobic-anoxic processes under complex water quality and temperature conditions by integrating indirect estimation of internal carbon sources, feedforward prediction of denitrification potential, dual characteristic endpoint identification, and adaptive correction mechanism of model parameters.

[0023] In the description of the embodiments of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0024] Terminology Explanation To facilitate understanding of this invention, the core terms involved are defined as follows: GAOs: Glycan bacteria, which are the core functional microorganisms responsible for synthesizing and storing internal carbon sources in the AOA process.

[0025] PHA: Polyhydroxyalkanoate, is the core carbon source for the endogenous denitrification process in the AOA process. It is synthesized and stored by GAOs in the anaerobic stage.

[0026] ORP plateau period: refers to the period of time during which the ORP value in the anaerobic stage remains stable after it drops to a preset range (e.g., -200 mV ~ -300 mV). For example, the criterion for determining the stable period is that the ORP fluctuation value is ≤5 mV within 5 consecutive sampling cycles. The sampling cycle can be set according to the actual operating conditions of the wastewater treatment plant, usually 1~5 minutes.

[0027] Nitrate knee point: refers to the oxygen-deficient NO3-dependent region. - When exhausted, the ORP curve changes from a rapidly declining state to a flat state at an inflection point; for example, the inflection point identification algorithm is that the rate of change of ORP is <0.5 mV / min within 3 consecutive sampling periods, and the sampling period is consistent with the sampling period of the ORP plateau period.

[0028] Internal carbon source: refers to PHA synthesized by GAOs in the anaerobic stage using influent carbon source, which serves as an electron donor for the denitrification reaction in the anoxic stage and is the core material basis for endogenous denitrification in the AOA process.

[0029] Figure 1 This is a schematic flowchart of the combined control method for anaerobic, aerobic, and anoxic processes provided by the present invention, as shown below. Figure 1 As shown, the method includes the following steps S1-S6.

[0030] Step S1: During the operation of the anaerobic section, the oxidation-reduction potential signal is collected, and the duration of the plateau period is determined based on the plateau period formed in the preset negative potential range of the oxidation-reduction potential curve.

[0031] Specifically, during the operation of the anaerobic section, functional microorganisms preferentially utilize the organic matter in the influent to synthesize internal carbon sources and store them inside the cells. Accompanying this metabolic process, the redox potential value in the reaction zone continuously decreases and enters the preset negative potential range. Subsequently, when the synthesis of internal carbon sources tends to be sufficient, the redox potential value remains relatively stable, thus forming a plateau period on the redox potential curve.

[0032] In some possible implementations, the plateau period is a stable segment formed by the redox potential curve within a preset negative potential range. This stable segment satisfies the condition that the redox potential fluctuation does not exceed a preset fluctuation threshold within a preset number of consecutive sampling cycles. For example, the preset negative potential range can be set to -200mV to -300mV, and the sampling cycle can be set to 1 minute to 5 minutes based on the on-site operating conditions. When the redox potential fluctuation does not exceed 5mV within 5 consecutive sampling cycles, it is determined to have entered the stable segment, and the duration of this stable segment is recorded as the plateau period duration.

[0033] It is understandable that the formation of the redox potential plateau is closely related to the synthesis and storage process of internal carbon sources. A longer plateau indicates higher functional microbial activity and more complete internal carbon source synthesis, showing a significant positive correlation between the two. By automatically identifying and statistically analyzing the plateau period, key characteristic quantities reflecting the internal carbon source reserve status can be obtained without directly measuring the internal carbon source, providing input for subsequent internal carbon source reserve estimation. For example... Figure 2 As shown, the horizontal axis represents time (min), the vertical axis represents the ORP value (mV), point A is the starting point of the plateau period, point B is the ending point of the plateau period, and segment AB is the plateau period formed by the redox potential curve in the preset negative potential range. Its duration t is the plateau period length.

[0034] Step S2: At the end of the anaerobic phase, based on the plateau duration, influent organic matter concentration, and water temperature, estimate the carbon source reserve in the system using the internal carbon source reserve estimation model.

[0035] Specifically, the internal carbon source reserve estimation model is established based on the plateau period duration, influent organic matter concentration, and water temperature. The internal carbon source reserve is positively correlated with both the plateau period duration and the influent organic matter concentration. The plateau period duration reflects the sufficiency of internal carbon source synthesis, the influent organic matter concentration reflects the raw material basis for internal carbon source synthesis, and water temperature affects the metabolic activity of functional microorganisms.

[0036] In some possible implementations, the internal carbon source reserve estimation model can be expressed as: PHA = f1(t, COD, T) Wherein, PHA represents the internal carbon source reserve, t represents the plateau period duration, COD represents the influent organic matter concentration, and T represents the water temperature. In the above model, the temperature correction term T within parentheses is used to compensate for the influence of water temperature on the metabolic activity of functional microorganisms. That is, when the water temperature drops by a preset threshold, the value of the temperature correction term is adjusted upward accordingly to reflect the characteristics of the internal carbon source synthesis rate changing with temperature. In some implementations, it can be configured such that for every preset temperature difference decrease in water temperature, the internal carbon source synthesis rate decreases by a preset proportion, thereby reducing the internal carbon source reserve by the same proportion. For example, for every 5°C decrease in temperature, the PHA synthesis rate decreases by 15~20%. For example, PHA = k × t × COD × (1 + β × (25-T)), where k is an empirical coefficient, typically ranging from 0.015 to 0.025, which can be fitted and calibrated based on actual wastewater treatment plant operating data; β is the temperature correction coefficient, typically ranging from 0.02 to 0.04, which can be determined by fitting actual wastewater treatment plant operating data and is used to correct the influence of water temperature on GAOs activity.

[0037] Understandably, by integrating the plateau duration, influent organic matter concentration, and water temperature to establish an estimation model, the model utilizes the plateau duration, a characteristic quantity that directly reflects the state of internal carbon source synthesis, while also incorporating the influencing factors of feedstock supply and metabolic activity. This significantly improves the estimation accuracy of internal carbon source reserves. This estimation method does not require the introduction of special detection hardware and can be achieved solely through mature online monitoring methods for oxidation-reduction potential, organic matter concentration, and temperature, making it highly practical for engineering applications.

[0038] Furthermore, in some possible implementations, the method can classify and determine the internal carbon source reserve status based on the plateau period duration: when the plateau period duration is less than a first duration threshold, it is determined to be insufficient reserve; when the plateau period duration is between the first and second duration thresholds, it is determined to be moderate reserve; when the plateau period duration is greater than the second duration threshold, it is determined to be sufficient reserve. Different reserve states can correspond to different subsequent operating strategies. For example, when the reserve is insufficient, carbon source replenishment and protection actions are triggered; when the reserve is sufficient, the operating parameters of the aerobic section are optimized. For example, when t < 20 min, it is determined to be insufficient carbon source reserve, triggering carbon source replenishment and protection actions; when 20 min ≤ t ≤ 40 min, it is determined to be moderate carbon source reserve, maintaining normal operating status; when t > 40 min, it is determined to be sufficient carbon source reserve, and the operating parameters of the aerobic section can be appropriately optimized to improve energy consumption utilization.

[0039] Step S3: At the end of the aerobic stage, based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, calculate the denitrification potential index using the denitrification potential prediction model, and generate the target operating time of the anoxic stage based on the denitrification potential index.

[0040] Specifically, the denitrification potential of the anoxic section is determined by the available internal carbon source and the nitrate nitrogen load to be removed. The higher the internal carbon source reserve and the lower the nitrate nitrogen concentration at the end of the aerobic section, the stronger the denitrification potential and the shorter the required anoxic section operation time.

[0041] In some possible implementations, the expression for the denitrification potential prediction model is: , Where P is the denitrification potential index and PHA is the internal carbon source reserve. This refers to the nitrate nitrogen concentration at the end of the aerobic section. The operating condition correction factor varies with water temperature and influent carbon-nitrogen ratio. This is a correction constant used to compensate for errors in online nitrate nitrogen detection. The operating condition correction coefficient α is used to correct for differences in denitrification rates under different water temperatures and influent C / N ratios. In some implementations, it can be configured to take a larger value under low water temperature and low C / N ratio conditions to reflect the increased demand for denitrification under these conditions. The correction constant ε is used to compensate for errors in online nitrate nitrogen detection, avoiding distortion of the potential index due to an excessively small denominator when the nitrate nitrogen concentration is low. Its value can be increased accordingly as the detection accuracy improves. For example, when the water temperature is 15~25℃ and the C / N ratio is 5~7, the value of α is 0.8~1.0, and α is negatively correlated with both water temperature and C / N ratio; when the water temperature is below 15℃, the value of α is 1.0~1.2, and the lower the water temperature, the closer the value of α is to 1.2; when C / N < 5, the value of α is 1.2~1.4, and the lower the C / N ratio, the closer the value of α is to 1.4; ε is a correction constant, with a value range of 0.5~1.0 mg / L, used to correct NO3. - Online detection error, the NO3 - The online detection error is typically ±0.5 mg / L. The value of ε is positively correlated with the detection accuracy; the higher the detection accuracy, the closer the value of ε is to 1.0 mg / L. Furthermore, in some possible implementations, the target duration of the hypoxic segment is equal to the product of the baseline hypoxic duration and the potential adjustment function, i.e., t 目标 = t 基础 ·g(P), where t 基础The baseline anoxic duration is set between 30 and 60 minutes, with the specific value determined based on the wastewater treatment plant's scale. In the AOA process, the anoxic HRT is typically 3 to 6 hours, therefore the baseline t value can range from 180 to 360 minutes. The potential adjustment function g(P) is a monotonically decreasing function of the denitrification potential index, expressed as g(P) = a - b · P, where a and b are positive constants. Upper and lower limits can be imposed on the value of g(P), and the corresponding boundary value is used when the calculated result exceeds the preset upper and lower limit range. For example, g(P) = 1.2 - 0.03 × P, and the value range of g(P) is 0.7 to 1.1.

[0042] Understandably, by linking the internal carbon source reserves with the nitrate nitrogen load through the denitrification potential index and mapping it to the target operating time of the anoxic section through the potential adjustment function, the operating time of the anoxic section can be dynamically allocated on demand according to the actual denitrification capacity of the system. The larger the denitrification potential index, the stronger the denitrification capacity of the system and the shorter the required operating time of the anoxic section. This effectively avoids the energy waste caused by fixed-duration control while ensuring thorough denitrification.

[0043] Step S4: During the operation of the anoxic section, real-time acquisition of redox potential signals and nitrate nitrogen concentration signals is conducted, and the denitrification endpoint is identified based on the characteristics of redox potential changes and nitrate nitrogen concentration changes.

[0044] Specifically, nitrate nitrogen is the direct substrate of denitrification, and its concentration decreasing to a low level is a direct manifestation of denitrification becoming more complete. At the same time, the change in redox potential is closely related to the concentration of nitrate nitrogen. When nitrate nitrogen tends to be depleted, the rate of decrease of the redox potential curve slows down significantly, forming a characteristic inflection point (i.e., the nitrate knee point).

[0045] In some possible implementations, identifying the denitrification endpoint based on the characteristics of redox potential changes and nitrate nitrogen concentration changes includes: determining that the denitrification endpoint has been reached when the rate of change of redox potential is less than a preset rate of change threshold and / or the nitrate nitrogen concentration is lower than a preset concentration threshold within a preset number of consecutive sampling periods. For example, when the rate of change of redox potential is less than 0.5 mV / min within three consecutive sampling periods, the redox potential is determined to have reached the nitrate knee; and / or when the nitrate nitrogen concentration is lower than a preset concentration threshold (e.g., a value within the range of 1.0 mg / L to 2.0 mg / L) within three consecutive sampling periods, the nitrate nitrogen concentration is determined to be within the target range. Meeting any one of the above conditions or simultaneously meeting the above conditions constitutes a determination that the denitrification endpoint has been reached.

[0046] Understandably, by combining the characteristics of redox potential changes and nitrate nitrogen concentration changes, the identification lag and misjudgment caused by water quality fluctuations or sensor noise, which are common when relying on only a single indicator, are avoided, significantly improving the accuracy and timeliness of denitrification endpoint identification. Figure 3 As shown, point C is the knee point of the redox potential curve for nitrates, and line D is the threshold line for nitrate concentration. When the rate of change of redox potential slows down to the knee point and / or the nitrate concentration drops below the threshold line, the denitrification endpoint is identified.

[0047] Step S5: When the denitrification endpoint is detected, the current anoxic section operation ends and the next process cycle begins.

[0048] Specifically, once the denitrification endpoint is identified during the operation of the anoxic section, the control system immediately terminates the current anoxic section operation to avoid energy waste caused by the ineffective extension of the anoxic section, and allows the process to enter the next operating cycle, thereby achieving real-time closed-loop correction of the actual running time of the anoxic section relative to the target running time.

[0049] Step S6: When the anoxic section has run for the target running time and the denitrification endpoint has not been identified, an alarm is triggered and deviation data is recorded. Based on the deviation data, the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model are corrected.

[0050] Specifically, if the anoxic section has run to the target running time generated in step S3, but the denitrification endpoint has not been identified in step S4, it indicates that the actual denitrification process is slower than predicted. The control system triggers an alarm and records the deviation data between the target running time and the actual denitrification process.

[0051] In some possible implementations, the parameters of the internal carbon source reserve estimation model and / or denitrification potential prediction model can be modified based on the statistical deviation between the target operating time and the actual endpoint time over multiple consecutive operating cycles. For example, when the actual endpoint time is consistently shorter than the target operating time, it indicates that the potential adjustment function overestimates the required anoxic period duration, and the baseline anoxic period can be adjusted accordingly, or the coefficients of the potential adjustment function can be adjusted. When the actual denitrification process is consistently slower than predicted, the empirical coefficients of the internal carbon source reserve estimation model or the operating condition correction coefficients of the denitrification potential prediction model can be modified accordingly.

[0052] Understandably, by using a model parameter adaptive correction mechanism based on operational deviations, the control system can continuously self-calibrate according to actual operating conditions during long-term operation, avoiding the problem of decreased control accuracy caused by operating condition fluctuations due to fixed model parameters, and ensuring long-term stability of control accuracy.

[0053] In some possible implementations, the method further includes a carbon source reserve early warning and protection mechanism: when the internal carbon source reserve is lower than a preset reserve threshold or the plateau period duration is less than a first duration threshold, a carbon source reserve early warning is triggered and at least one of the following control actions is executed: reducing the aeration intensity of the aerobic section; reducing the dissolved oxygen concentration setpoint of the aerobic section; adjusting the influent distribution method; and extending the hydraulic retention time of the anaerobic section. For example, when PHA < 60 mg / L or t < 20 min, a carbon source reserve early warning is triggered, and any of the following control actions are executed to increase the internal carbon source reserve: (a) reducing the aeration intensity of the aerobic section, lowering the DO concentration of the aerobic section from the conventional 1.5~2.5 mg / L to 0.8~1.2 mg / L, thereby reducing the PHA consumption rate; (b) adjusting the influent distribution method, extending the hydraulic retention time of the anaerobic section by 5~10 min, thereby increasing the carbon source supply in the anaerobic section and providing sufficient raw materials for GAOs to synthesize PHA.

[0054] Understandably, reducing the aeration intensity or dissolved oxygen concentration setpoint in the aerobic section can slow down the consumption of internal carbon sources in the aerobic section, allowing more internal carbon sources to be retained in the anoxic section for denitrification. Adjusting the influent distribution method or extending the hydraulic retention time in the anaerobic section can increase the carbon source supply in the anaerobic section, providing more sufficient raw materials for functional microorganisms to synthesize internal carbon sources. Through these carbon source protection measures, timely intervention can be provided when internal carbon source reserves are insufficient, avoiding denitrification failure due to insufficient internal carbon sources and improving the robustness of the process under adverse conditions such as low carbon-to-nitrogen ratios.

[0055] In some possible implementations, the method further includes end-to-end auxiliary monitoring and sludge discharge control: real-time monitoring of mixed liquor suspended solids concentration (MLSS) and sludge settling ratio (SV). 30 The ammonia nitrogen removal rate is also considered. When the suspended solids concentration of the mixed liquor exceeds a preset upper limit, the sludge settling ratio exceeds a preset upper limit, and the ammonia nitrogen removal rate decreases from the benchmark value by more than a preset amount, the aerobic section's end-of-section sludge discharge action is triggered, and the sludge discharge time is dynamically adjusted according to changes in sludge concentration. For example, when MLSS > 4000 mg / L and SV < 4000 mg / L... 30 When the MLSS is greater than 50% and the ammonia nitrogen removal rate decreases by more than 15% from the baseline value, the sludge discharge action at the end of the aerobic section is triggered. The sludge discharge rate is 3.5% of the total sludge volume of the system per day. The sludge discharge time is dynamically adjusted according to the changes in sludge concentration until the MLSS drops to a reasonable range.

[0056] It is understandable that excessively high mixed liquor suspended solids concentration, excessively high sludge settling ratio, and significantly reduced ammonia nitrogen removal rate usually indicate sludge aging and excessively long sludge age, which affect nitrification and internal carbon source synthesis capacity. By triggering sludge discharge at the end of the aerobic stage and dynamically adjusting the sludge discharge time under such circumstances, sludge can be renewed in a timely manner and its activity restored, thereby ensuring nitrification effect and internal carbon source synthesis rate, and indirectly supporting the stable denitrification in the anoxic stage.

[0057] The following describes the combined control device for anaerobic, aerobic, and hypoxic processes provided by the present invention. The device described below and the method described above can be referred to in correspondence.

[0058] Figure 4 This is a schematic diagram of the structure of the combined anaerobic-aerobic-anoxic process control device provided by the present invention, as shown below. Figure 4 As shown, the device includes an internal carbon source reserve estimation module 4, a denitrification potential prediction module 5, an endpoint identification and correction module 6, and a control system 7. The internal carbon source reserve estimation module includes a plateau period identification unit and an internal carbon source estimation unit, and the endpoint identification and correction module includes an endpoint identification unit and a model correction unit. The plateau phase identification unit is used to collect oxidation-reduction potential signals during the operation of the anaerobic section and determine the plateau phase duration based on the plateau phase formed in the preset negative potential range of the oxidation-reduction potential curve. The internal carbon source estimation unit is used to estimate the amount of internal carbon source reserves in the system at the end of the anaerobic phase, based on the duration of the plateau period, the concentration of organic matter in the influent, and the water temperature, using an internal carbon source reserve estimation model. The denitrification potential prediction module is used to calculate the denitrification potential index at the end of the aerobic stage based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, and to generate the target operating time of the anoxic stage based on the denitrification potential index. The endpoint identification unit is used to collect redox potential signals and nitrate nitrogen concentration signals in real time during the anoxic section operation, and to identify the denitrification endpoint based on the characteristics of redox potential changes and nitrate nitrogen concentration changes. The control system is used to terminate the current anoxic section and enter the next process cycle when the denitrification endpoint is detected. The model correction unit is used to trigger an alarm and record deviation data when the denitrification endpoint is not identified after the target running time in the anoxic section, and to correct the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model based on the deviation data.

[0059] Based on the above embodiments, the plateau period identification unit is specifically used to: determine the segment of the redox potential curve that fluctuates within a preset negative potential range for a preset number of consecutive sampling cycles as a plateau period, and count its duration as the plateau period duration.

[0060] Based on the above embodiments, the internal carbon source estimation unit is specifically used to: estimate the internal carbon source reserve based on the positive correlation between the internal carbon source reserve and the plateau period duration and the positive correlation with the influent organic matter concentration, and in combination with water temperature correction.

[0061] Based on the above embodiments, the denitrification potential prediction module is specifically used to: calculate the denitrification potential index according to the denitrification potential prediction model, and generate the target running time of the anoxic segment by multiplying the potential adjustment function, which is a monotonically decreasing function of the denitrification potential index, with the basic anoxic duration.

[0062] Based on the above embodiments, the endpoint identification unit is specifically used to: determine that the denitrification endpoint has been reached when the rate of change of redox potential is less than a preset rate of change threshold for a consecutive preset number of sampling periods and / or the nitrate nitrogen concentration is lower than a preset concentration threshold for a consecutive preset number of sampling periods.

[0063] Based on the above embodiments, the device further includes a carbon source protection module and an auxiliary monitoring module, which are respectively used to perform carbon source protection actions when the internal carbon source reserve is lower than a preset reserve threshold or the plateau period duration is less than a first duration threshold, and to trigger the aerobic section end sludge discharge action when the sludge state indicators meet preset conditions.

[0064] The following are some specific application examples. Example 1: Application under normal operating conditions Operating parameters: An AOA process at a municipal wastewater treatment plant, with a treatment capacity of 50,000 tons / day. Influent COD concentration: 200 mg / L, C / N ratio: approximately 5.7, water temperature: 20℃, MLSS: 3200 mg / L, MLVSS: ≈2500 mg / L. Basic anoxic duration tbasic = 300 min. The operating parameters used in this embodiment are typical of municipal wastewater, fully verifying the versatility and stability of the method of this invention.

[0065] Monitoring equipment configuration: An online COD meter (detection accuracy ±5 mg / L) is installed at the inlet; ORP electrodes (detection range -500~500 mV, accuracy ±2 mV) are installed in the anaerobic and anoxic tanks; an online nitrate meter (detection accuracy ±0.1 mg / L) is installed at the end of the aerobic tank; an online nitrate meter and ORP electrode are installed at the end of the anoxic tank; an online MLSS meter and thermometer are installed throughout the entire process to ensure the accuracy of monitoring data.

[0066] Control process: (1) Anaerobic section reserve assessment: During the operation of the anaerobic section, the ORP curve was monitored to have a plateau period near -250 mV, with a plateau period duration of t=38 min, influent COD=200 mg / L, and water temperature T=20℃. Substituting into the internal carbon source reserve estimation model (k=0.02, β=0.03): PHA = 0.02 × 38 × 200 × (1+0.03×(25-20)) = 0.02 × 38 × 200× 1.15 ≈ 70 mg / L. According to the judgment rule, 38 min is between 20 and 40 min, indicating a moderate carbon source reserve, and the aeration intensity of the conventional aerobic section should be maintained (DO=1.8 mg / L).

[0067] (2) Prediction of aerobic section potential: When the aerobic section ends, NO3 is detected at the end of the aerobic section. - -N=25 mg / L, NH3-N<0.5 mg / L (nitrification complete), influent C / N=5.7, water temperature 20℃. Based on the correction rule, α=0.9 (water temperature 15~25℃, C / N=5~7), correction constant ε=0.8 mg / L. Substituting into the denitrification potential prediction model, the calculation is: P = 0.9 × 70 / (25+0.8) = 63 / 25.8 ≈ 2.44. The potential adjustment function g(P) = 1.2 - 0.03 × 2.44 ≈ 1.127, taking the upper limit of the range as g(P)=1.1. The target anoxic duration ttarget is dynamically set to 300 × 1.1 = 330 min (5.5 hours).

[0068] Data analysis: The P-value of approximately 2.44 indicates that the internal carbon source corresponding to a unit nitrate nitrogen load is not very abundant, therefore the target duration was extended by 10% compared to the baseline duration. At 20°C, the endogenous denitrification rate is approximately 1.9–2.2 mg NO3. - -N / (gVSS·h), when MLVSS=2.5 g / L, the volumetric rate is about 4.8~5.5 mg / (L·h), and the theoretical time to remove 25 mg / L nitrate nitrogen is about 4.5~5.2 hours. The target of 330 min (5.5 hours) leaves a reasonable margin to ensure complete denitrification.

[0069] (3) Endpoint correction in the hypoxic phase: During the hypoxic phase operation, ORP and NO3 are monitored in real time. - -N. At 315 min, the ORP curve showed a clear nitrate knee point (ORP change rate = 0.3 mV / min for 3 consecutive sampling periods, meeting the criterion of <0.5 mV / min), while NO3... -When the -N concentration dropped to 0.8 mg / L (below 1.0 mg / L for three consecutive sampling cycles), both characteristics met the endpoint identification criteria, and the control system immediately ended the hypoxic phase operation and entered the next cycle. The actual operation time was 315 minutes, completing the cycle 15 minutes ahead of the target of 330 minutes.

[0070] (4) Adaptive correction of model parameters: After 30 days of continuous operation, the deviation between the target duration and the actual endpoint duration of the hypoxic period was statistically analyzed. The average actual endpoint duration was 310 min, the average target duration was 328 min, and the average deviation was -18 min (approximately -5.5%). The system automatically adjusted the baseline hypoxic duration tbase from 300 min to 295 min to make the model more closely match the actual working conditions.

[0071] Control effect: Outflow NO3 - -N=0.8 mg / L, effluent TN≤1.5 mg / L, consistently meeting the standard; the actual duration of the anoxic phase is 315 min, which avoids ineffective extension compared to the fixed duration control method; after 30 days of continuous operation, the effluent TN remains stable below 1.5 mg / L, achieving a compliance rate of 99%.

[0072] Example 2: Application Case of Abnormal Operating Conditions (Insufficient Carbon Source Reserves) Operating parameters: Winter operation, water temperature 12℃, influent COD concentration low, fluctuating between 120~150 mg / L, C / N ratio 4.0~4.5, MLSS 3000~3500 mg / L, basic anoxic duration tbasic = 300 min. This operating condition is a typical low C / N ratio and low water temperature abnormal condition, which can verify the robustness of the method of this invention.

[0073] Control process: (1) Anaerobic stage reserve assessment: The monitoring showed that the ORP plateau period in the anaerobic stage lasted for t=16 min, the influent COD was 130 mg / L, and the water temperature was T=12℃. Substituting into the internal carbon source reserve estimation model, the calculation was: PHA = 0.02 × 16 × 130 × (1+0.03×(25-12)) = 0.02 × 16 × 130 × 1.39 ≈ 57.8 mg / L. According to the judgment rule, t=16 min<20 min, indicating insufficient carbon source reserve, triggering a carbon source reserve warning.

[0074] (2) Control actions: The system automatically performs the following two control actions: ① Reduce the aeration intensity of the aerobic section from the conventional 2.0 mg / L to 1.0 mg / L to reduce the PHA consumption rate; ② Adjust the influent distribution method and extend the hydraulic retention time of the anaerobic section by 10 min to increase the carbon source reserve.

[0075] (3) Predicted potential of the aerobic section: Water temperature 12℃, C / N=4.1, α=1.3 (C / N<5, low temperature) and ε=0.8 mg / L are determined according to the correction rule. Under low temperature and low C / N conditions, the effect of SND is further limited, and NO3 at the end of the aerobic section - -N is approximately 24 mg / L. The denitrification potential index is calculated as: P = 1.3 × 57.8 / (24 + 0.8) = 75.1 / 24.8 ≈ 3.03. The potential adjustment function g(P) = 1.2 - 0.03 × 3.03 ≈ 1.109, taking the upper limit of the range as g(P) = 1.1. The target hypoxia duration ttarget = 300 × 1.1 = 330 min.

[0076] (4) End point of hypoxia phase: When running for 330 min, NO3 - -N remained at 6.8 mg / L, ORP did not reach its knee point, and the denitrification endpoint was not detected. An alarm was triggered, and the system recorded the deviation data. Analysis showed that the estimated PHA level was 57.8 mg / L based on COD / NO3. - The -N=4 calculation only removes approximately 14.5 mg / L of nitrate nitrogen, leaving about 9.5 mg / L of nitrate nitrogen, which is within the model error range compared to the actual residual of 6.8 mg / L. This deviation data is fed back into the internal carbon source reserve estimation model, causing the empirical coefficient k to be lowered from 0.02 to 0.018, reflecting the lower-than-expected actual PHA synthesis efficiency at low water temperatures.

[0077] Control effect: Under extreme conditions of severe carbon source deficiency in the influent, although complete denitrification was not achieved through feedforward early warning and parameter adjustment, the NO3 in the effluent was reduced. - -N was approximately 6.8 mg / L, which is better than the condition without regulation; the model parameters were adaptively corrected, accumulating experience for subsequent operations.

[0078] Example 3: Application Case of Sludge Discharge Control Operating parameters: During a certain period, MLSS was monitored at 4300 mg / L, SV30 at 55%, and the NH3-N removal rate decreased from 2.5 mg / (L·h) during normal operation to 1.7 mg / (L·h) (a decrease of 32% from the baseline value, exceeding the 15% trigger threshold). The NH3-N concentration at the end of the aerobic section increased from 0.5 mg / L to 1.0 mg / L, indicating that the nitrifying bacteria were aging and the sludge age was too long.

[0079] Control action: Trigger sludge discharge control to discharge sludge from the end of the aerobic section at a rate of 3.5% of the total sludge volume of the system per day for 6 days, gradually reducing MLSS to 3450 mg / L and SV30 to 46%.

[0080] Control effects: After sludge discharge, the NH3-N removal rate recovered to 2.3 mg / (L·h), the effluent NH3-N concentration decreased to 0.4 mg / L, and the PHA synthesis rate increased from 0.9 mg / (L·h) before sludge discharge to 1.2 mg / (L·h). The subsequent denitrification effect in the anoxic zone also improved, and the effluent NO3... - -N remains stable below 0.8 mg / L.

[0081] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 can call logic instructions in the memory 530 to execute a joint control method for anaerobic-aerobic-anoxic processes, which includes: During the anaerobic stage, oxidation-reduction potential (ORP) signals are collected, and the plateau duration is determined based on the plateau period formed by the ORP curve in the preset negative potential range. At the end of the anaerobic stage, the internal carbon source reserve is estimated using an internal carbon source reserve estimation model based on the plateau duration, influent organic matter concentration, and water temperature. At the end of the aerobic stage, the denitrification potential index is calculated using a denitrification potential prediction model based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-to-nitrogen ratio. The target operating time for the anoxic stage is then generated based on the denitrification potential index. During the anoxic stage, ORP and nitrate nitrogen concentration signals are collected in real time, and the denitrification endpoint is identified based on the ORP and nitrate nitrogen concentration change characteristics. When the denitrification endpoint is identified, the current anoxic stage operation ends, and the next process cycle begins. If the denitrification endpoint is not identified by the target operating time in the anoxic stage, an alarm is triggered, and deviation data is recorded. The parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model are corrected based on the deviation data.

[0082] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0083] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the anaerobic-aerobic-anoxic process combined control method provided by the above methods.

[0084] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the anaerobic-aerobic-anoxic process combined control method provided by the above methods.

[0085] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0086] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for combined control of anaerobic, aerobic, and anoxic processes, characterized in that, The method includes: Step S1: During the operation of the anaerobic section, collect the oxidation-reduction potential signal and determine the duration of the plateau period based on the plateau period formed in the preset negative potential range of the oxidation-reduction potential curve. Step S2: At the end of the anaerobic phase, based on the duration of the plateau period, the concentration of organic matter in the influent, and the water temperature, estimate the amount of carbon source reserves in the system using the internal carbon source reserve estimation model. Step S3: At the end of the aerobic stage, based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, calculate the denitrification potential index using the denitrification potential prediction model, and generate the target operating time of the anoxic stage based on the denitrification potential index. Step S4: During the operation of the anoxic section, collect the redox potential signal and nitrate nitrogen concentration signal in real time, and identify the denitrification endpoint based on the characteristics of the redox potential change and the characteristics of the nitrate nitrogen concentration change. Step S5: When the denitrification endpoint is detected, the current anoxic section operation ends and the next process cycle begins; Step S6: When the anoxic section has run for the target running time and the denitrification endpoint has not been identified, an alarm is triggered and deviation data is recorded. Based on the deviation data, the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model are corrected.

2. The method according to claim 1, characterized in that, The plateau period is a stable segment formed by the redox potential curve within a preset negative potential range. The stable segment satisfies that the redox potential fluctuation does not exceed a preset fluctuation threshold within a preset number of consecutive sampling periods.

3. The method according to claim 1, characterized in that, The internal carbon source reserve estimation model is established based on the plateau period duration, influent organic matter concentration, and water temperature. The internal carbon source reserve is positively correlated with the plateau period duration and the influent organic matter concentration.

4. The method according to claim 1, characterized in that, The expression for the denitrification potential prediction model is: Where P is the denitrification potential index, This refers to the nitrate nitrogen concentration at the end of the aerobic section. This is a correction factor for operating conditions that varies with water temperature and influent carbon-nitrogen ratio; This is a correction constant used to compensate for errors in online nitrate nitrogen detection.

5. The method according to claim 1, characterized in that, In step S2, the target duration of the anoxic period is equal to the product of the baseline anoxic duration and the potential adjustment function, wherein the potential adjustment function is a monotonically decreasing function of the denitrification potential index.

6. The method according to claim 1, characterized in that, Identifying denitrification endpoints based on redox potential and nitrate nitrogen concentration changes includes: When the rate of change of redox potential is less than a preset rate of change threshold and / or the nitrate nitrogen concentration is lower than a preset concentration threshold within a preset number of consecutive sampling periods, the denitrification endpoint is determined to have been reached.

7. The method according to claim 1, characterized in that, When the internal carbon source reserve is lower than the preset reserve threshold or the plateau period duration is less than the first duration threshold, a carbon source reserve warning is triggered and at least one of the following control actions is executed: reducing the aeration intensity of the aerobic section; reducing the dissolved oxygen concentration set value of the aerobic section; adjusting the influent distribution method; and extending the hydraulic retention time of the anaerobic section.

8. The method according to claim 1, characterized in that, The method further includes: Real-time monitoring of mixed liquor suspended solids concentration, sludge settling ratio, and ammonia nitrogen removal rate; When the concentration of suspended solids in the mixed liquor is higher than the preset upper limit, the sludge settling ratio is higher than the preset upper limit, and the ammonia nitrogen removal rate decreases from the benchmark value by more than a preset amount, the sludge discharge action at the end of the aerobic section is triggered, and the sludge discharge time is dynamically adjusted according to the change in sludge concentration.

9. A combined control device for anaerobic-aerobic-anoxic processes, used to implement the method according to any one of claims 1 to 8, characterized in that, The device includes an internal carbon source reserve estimation module, a denitrification potential prediction module, an endpoint identification and correction module, and a control system. The internal carbon source reserve estimation module includes a plateau period identification unit and an internal carbon source estimation unit, and the endpoint identification and correction module includes an endpoint identification unit and a model correction unit. The plateau phase identification unit is used to collect oxidation-reduction potential signals during the operation of the anaerobic section and determine the plateau phase duration based on the plateau phase formed in the preset negative potential range of the oxidation-reduction potential curve. The internal carbon source estimation unit is used to estimate the amount of internal carbon source reserves in the system at the end of the anaerobic phase, based on the duration of the plateau period, the concentration of organic matter in the influent, and the water temperature, using an internal carbon source reserve estimation model. The denitrification potential prediction module is used to calculate the denitrification potential index at the end of the aerobic stage based on the internal carbon source reserve, the nitrate nitrogen concentration at the end of the aerobic stage, and the influent carbon-nitrogen ratio, and to generate the target operating time of the anoxic stage based on the denitrification potential index. The endpoint identification unit is used to collect redox potential signals and nitrate nitrogen concentration signals in real time during the anoxic section operation, and to identify the denitrification endpoint based on the characteristics of redox potential changes and nitrate nitrogen concentration changes. The control system is used to terminate the current anoxic section and enter the next process cycle when the denitrification endpoint is detected. The model correction unit is used to trigger an alarm and record deviation data when the denitrification endpoint is not identified after the target running time in the anoxic section, and to correct the parameters of the internal carbon source reserve estimation model and / or the denitrification potential prediction model based on the deviation data.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the combined control method for anaerobic-aerobic-anoxic processes as described in any one of claims 1 to 8.

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