Food waste water treatment regulation method and system

Abstract

The present application relates to wastewater treatment technical field, especially a kind of food wastewater treatment regulation method and system, the method includes: during the safe mode operation, with preset tentative period, on the basis of fixed low flow dosing, add preset pulse quantity of internal carbon source liquid to the internal reflux path, as tentative pulse;After the tentative pulse is added, the actual drop rate of nitrate concentration in the internal reflux path is obtained as the tentative response rate;The tentative response rate is compared with the preset recovery reference rate, and the comparison result is obtained;By adding tentative pulse under safe mode and monitoring response to judge the recovery of microbial activity, and combined with transition control and upstream load prediction to safely and smoothly exit safe mode, with the advantages of being able to exit safe mode according to the actual activity recovery of microorganism, intelligently judge the timing, avoid blind exit or long time maintaining conservative mode.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a food wastewater treatment control method and system. Background Art

[0002] Wastewater treatment, particularly those utilizing biological denitrification processes (such as anoxic-aerobic, or A / O, processes), is highly dependent on the activity and stability of microorganisms. In A / O processes, the denitrification process in the anoxic section requires a sufficient carbon source as an electron donor to reduce nitrate to nitrogen gas. However, in actual operation, fluctuations in influent quality, particularly changes in carbon source content, often inhibit microbial activity in the anoxic section, reducing denitrification efficiency. This, in turn, impacts the overall denitrification performance of the system and causes excessive total nitrogen in the effluent. When the system detects that microbial activity within the anoxic treatment unit is inhibited, countermeasures, such as entering a safety mode, are typically required to prevent further deterioration of treatment performance or system failure. In safety mode, conservative control strategies may be employed, such as adding a carbon source at a fixed, low flow rate, to maintain basic microbial activity.

[0003] However, determining whether microbial activity has recovered sufficiently to exit safe mode and return to normal control mode presents a challenge for existing technologies. Blindly exiting safe mode could cause the system to crash again, while maintaining the conservative safe mode for an extended period could compromise treatment efficiency and economics. Existing technologies lack an effective method that can intelligently determine the system's recovery status based on the actual microbial response and safely and smoothly exit safe mode.

[0004] In view of the above problems, the existing technology is in urgent need of improvement. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a food wastewater treatment control method and system.

[0006] In a first aspect, the present invention provides a method for controlling food wastewater treatment, which is applied to a wastewater treatment system, wherein the wastewater treatment system includes an anoxic treatment unit for denitrification and an aerobic treatment unit for nitrification, and is provided with an internal reflux path for returning the effluent of the aerobic treatment unit to the anoxic treatment unit. The method comprises:

[0007] During the safe mode operation, a preset pulse amount of internal carbon source liquid is added to the internal reflux path at a preset trial period and at a fixed low flow rate as a trial pulse;

[0008] After the probe pulse is added, obtaining an actual decreasing rate of the nitrate concentration in the internal reflux path as a probe response rate;

[0009] Comparing the trial response rate with a preset recovery reference rate to obtain a comparison result;

[0010] When the comparison result satisfies a preset exit condition, the safety mode is terminated and the normal control mode is restored to control the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path.

[0011] The core innovation of this application is that by introducing periodic trial pulse addition and a response evaluation mechanism based on the nitrate reduction rate in the safety mode, dynamic monitoring and judgment of the recovery of microbial activity in the anoxic treatment unit are achieved, and the timing of exiting the safety mode is intelligently determined according to the actual recovery status, thereby avoiding carbon source waste and promoting stable recovery of the system.

[0012] In a second aspect, a food wastewater treatment control system is provided, the system comprising:

[0013] a trial pulse dosing module, configured to, during operation in the safe mode, dosing a preset pulse amount of the internal carbon source liquid into the internal reflux path at a preset trial period and on the basis of a fixed low flow rate as a trial pulse;

[0014] a probe response rate acquisition module, configured to acquire, after the probe pulse is added, an actual decreasing rate of the nitrate concentration in the internal reflux path as a probe response rate;

[0015] A comparison module, configured to compare the probe response rate with a preset recovery reference rate to obtain a comparison result;

[0016] The mode switching control module is used to terminate the safety mode and restore to the normal control mode of controlling the addition of the internal carbon source liquid according to the real-time detection signal of the nitrate concentration in the internal reflux path when the comparison result meets the preset exit condition.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] By adding a test pulse in the safety mode and monitoring the response to judge the recovery of microbial activity, and combining transition control and upstream load prediction to safely and smoothly exit the safety mode, it has the advantage of being able to intelligently judge the timing of exiting the safety mode based on the actual activity recovery of the microorganisms, avoiding blind exit or maintaining the conservative mode for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1Flow chart of the method of the present invention.

[0020] Figure 2 Schematic diagram of the system structure of the present invention.

[0021] In the figure: 201, a trial pulse addition module; 202, a trial response rate acquisition module; 203, a comparison module; 204, a mode switching control module. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0023] 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 the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0024] When microbial activity in anoxic treatment units is suppressed, conventional wastewater treatment systems enter a safe mode, employing a fixed, low-flow rate to dosing an internal carbon source solution. This approach cannot dynamically adjust the carbon source dosage based on the actual microbial recovery, resulting in a mismatch between the carbon source dosage and microbial demand. This can lead to slow microbial recovery, prolonged safe mode operation, or excessive carbon source dosage, resulting in waste.

[0025] For example, consider a wastewater treatment system whose anoxic treatment unit experiences a significant decrease in microbial activity due to fluctuations in the influent carbon source or the impact of toxic substances. The system recognizes this condition and enters safe mode. In this safe mode, the system injects an internal carbon source liquid into the internal recirculation path at a preset, fixed low flow rate. However, microbial recovery is a dynamic process, and their carbon source demand is not constant. If microbial recovery is slow, a fixed low flow rate may not be sufficient to effectively stimulate activity. If recovery is rapid, a fixed low flow rate may be conservative, failing to fully utilize the carbon source to accelerate recovery. This fixed injection strategy cannot adapt to the dynamic changes in microbial demand during recovery. If these issues are not addressed, the wastewater treatment system will operate inefficiently for extended periods after microbial activity is suppressed. Adding a fixed low flow rate of carbon source may slow microbial recovery, affecting overall denitrification efficiency and increasing treatment costs. Furthermore, since the degree of microbial recovery cannot be accurately determined, the timing of the system's exit from safe mode is difficult to determine. Exiting the system too early could lead to unstable treatment results, or too late could lead to unnecessary carbon source consumption and increased operating costs.

[0026] To this end, this application Figure 1 A food wastewater treatment control method is shown, which is applied to a wastewater treatment system. The wastewater treatment system includes an anoxic treatment unit for denitrification and an aerobic treatment unit for nitrification, and is provided with an internal return path for returning the effluent of the aerobic treatment unit to the anoxic treatment unit. When the wastewater treatment system recognizes that the microbial activity in the anoxic treatment unit is inhibited, it can enter a safety mode. In the safety mode, an internal carbon source liquid is added to the internal return path at a fixed low flow rate. The method includes:

[0027] During the safe mode operation, a preset pulse amount of internal carbon source liquid is added to the internal reflux path at a preset trial period and at a fixed low flow rate as a trial pulse;

[0028] After the trial pulse is added, the actual decreasing rate of the nitrate concentration in the internal reflux path is obtained as the trial response rate;

[0029] Comparing the trial response rate with a preset recovery reference rate to obtain a comparison result;

[0030] When the comparison result meets the preset exit condition, the safety mode is terminated and the normal control mode is restored to control the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path.

[0031] Among them, the safety mode refers to a special operating state entered by the system when it recognizes that the activity of microorganisms in the anoxic treatment unit is suppressed, and its purpose is to protect the stability of the system and avoid further deterioration of the activity of microorganisms; wherein, the preset trial cycle refers to the predetermined time interval for the addition of trial pulses during the operation of the safety mode, which can be set according to the system scale, wastewater characteristics or experience, and its main purpose is to periodically detect the recovery of microorganisms; wherein, the preset pulse amount refers to the predetermined volume or flow of internal carbon source liquid added additionally in each trial cycle, which can be set according to the system capacity and expected response intensity, and its main purpose is to apply a controllable stimulus to the microorganisms; wherein, the trial response rate refers to the actual rate at which the nitrate concentration in the internal reflux path decreases after the trial pulse is added, which reflects the microorganism's response to the additional carbon source. Immediate utilization capability is mainly used to quantitatively evaluate the degree of recovery of microbial activity; wherein, the preset recovery reference rate refers to a predetermined minimum nitrate reduction rate threshold used to judge whether the microbial activity has recovered to a level sufficient to exit the safety mode. It can be set according to system design standards or historical operating data. It is mainly used to provide an objective recovery judgment standard; wherein, the preset exit condition refers to a predetermined logical condition used to judge when to terminate the safety mode and resume normal control. It is usually based on the comparison result of the trial response rate and the recovery reference rate. It is mainly to achieve intelligent exit from the safety mode; wherein, the conventional control mode refers to the system under normal operating conditions, which controls the internal carbon source liquid addition method according to the real-time detection signal of the nitrate concentration in the internal reflux path. Its purpose is to maintain efficient and stable denitrification effect.

[0032] The solution of the present application achieves its function in the following manner: when the wastewater treatment system recognizes that the microbial activity in the anoxic treatment unit is suppressed and enters the safe mode, the system first maintains a fixed low-flow internal carbon source liquid addition to provide a basic carbon source. On this basis, the method adds an additional preset pulse amount of internal carbon source liquid according to a preset trial cycle. This pulse addition serves as a test of microbial activity. After adding the trial pulse, the system obtains the actual rate of decrease of nitrate concentration in the internal reflux path, which characterizes the degree of response of the microorganisms to the additional carbon source, i.e., the trial response rate. Subsequently, the system compares the obtained trial response rate with the preset recovery reference rate. The comparison result is used to determine whether the microbial activity has recovered to a level that can exit the safe mode. When the comparison result meets the preset exit condition, the system terminates the safe mode operation and switches back to the conventional control mode in which the internal carbon source liquid addition is controlled according to the real-time detection signal of the nitrate concentration in the internal reflux path. The entire process forms a closed loop, which dynamically adjusts the duration of the safety mode through periodic probing and response evaluation to ensure timely switching to efficient conventional control after microbial recovery, avoiding unnecessary inefficient operation and carbon source consumption.

[0033] In some preferred embodiments, the present application is implemented as follows: When the system enters safe mode, the internal carbon source liquid is added at a fixed rate per hour. Simultaneously, the system sets a trial cycle, for example, every 30 minutes. At the beginning of each trial cycle, the system adds a preset pulse of internal carbon source liquid on top of the fixed low rate, for example, momentarily increasing the rate of addition and maintaining it for 1 minute. For a period of time after the pulse addition ends, for example, the next 5 minutes, the system continuously monitors changes in nitrate concentration in the internal recirculation path and calculates the average rate of decrease in nitrate concentration during this period as the trial response rate. The system presets a recovery baseline rate, for example, a nitrate concentration decrease of 0.5 mg / L per minute. The system compares the calculated trial response rate with the recovery baseline rate. A preset exit condition can be set such that the trial response rate is greater than or equal to the recovery baseline rate. When this comparison meets this condition, the system determines that microbial activity has recovered, immediately terminates safe mode, and switches to conventional control mode based on real-time nitrate concentration feedback, for example, using a PID controller to adjust the carbon source addition rate based on the deviation of the nitrate concentration from the target value.

[0034] As an embodiment of the present invention, when the comparison result satisfies a preset exit condition, the steps of terminating the safety mode and resuming the normal control mode of controlling the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path include:

[0035] Initiate a transition control phase instead of reverting directly to normal control mode;

[0036] During the transition control phase, a reference injection speed is determined which increases gradually with the time course of the transition control phase;

[0037] In the transient control stage, a feedback injection acceleration is determined according to a deviation between the real-time nitrate concentration in the internal reflux path and a target value;

[0038] Based on the reference dosing speed and the feedback dosing speed, and according to a control weight that increases over time, the dosing speed of the internal carbon source liquid is determined;

[0039] After the preset end condition is met in the transition control phase, the transition control phase is terminated and the control mode is switched to the normal control mode.

[0040] Among them, the transition control stage refers to an intermediate operating state between the safety mode and the conventional control mode. Its purpose is to provide a buffer period so that the system can smoothly recover from the suppressed state to the normal operating state. Its continuous process can be defined by time-based stage division or system state judgment; the baseline addition acceleration refers to a gradually increasing carbon source addition amount or acceleration rate preset according to the process of the transition stage without considering the real-time feedback signal during the transition control stage. Its purpose is to provide a basic, time-increasing carbon source supply for the gradually recovering active microorganisms. It can be determined by linear, exponential or other increasing functions; the feedback addition acceleration refers to the difference between the nitrate concentration in the internal reflux path monitored in real time and the expected target value during the transition control stage. The difference is calculated by the feedback control algorithm to correct the baseline injection acceleration. Its purpose is to fine-tune the carbon source injection according to the actual denitrification demand. It can be achieved by PID control, fuzzy control or other feedback control algorithms; the control weight refers to a parameter used to balance the influence of the baseline injection acceleration and the feedback injection acceleration when determining the final carbon source injection acceleration. The weight increases with time, which means that the influence of feedback control on the total injection acceleration gradually increases in the later stage of the transition stage. It can be determined by a function that increases from a lower value to a higher value over time; the preset end condition refers to a series of pre-set standards used to determine when the transition control stage ends and switches to the conventional control mode. These standards can be based on time, system performance indicators or external events.

[0041] The present invention's solution, after meeting the safety mode exit criteria, does not immediately switch to normal control mode. Instead, it initiates a transition control phase. During this transition control phase, the carbon source dosage consists of two components: a baseline dosage rate that increases over time, providing a baseline carbon source supply for the gradually recovering microbial activity; and a feedback dosage rate calculated based on the deviation of the nitrate concentration in the internal recirculation path from the target value, enabling the system to adjust in real time to meet actual denitrification needs. Over the course of the transition control phase, the influence of the feedback dosage rate on the total dosage rate (reflected by an increasing control weight) gradually increases, meaning the control strategy gradually shifts from a pre-set recovery path to feedback regulation based on real-time performance. Only when the transition control phase meets the pre-set termination criteria, indicating that the system has reached a certain level of stability or recovery, does it finally switch back to normal control mode based entirely on real-time nitrate concentration feedback. This phased, progressive control strategy avoids the system shock and instability that could result from a direct switch, ensuring smooth operation of the wastewater treatment system and stable effluent quality. Combined with a method for determining the degree of recovery of microbial activity based on a trial pulse response, this solution can use a smooth transition method to switch modes when the microbial activity recovers sufficiently to support conventional control. This effectively solves the technical problem of how to determine the appropriate recovery time and achieve smooth control mode switching after microbial activity is suppressed.

[0042] As an embodiment of the present invention, after the transition control phase meets a preset end condition, the step of terminating the transition control phase and switching to the normal control mode includes:

[0043] Obtaining upstream load information representing future production activities of upstream enterprises, including the preset start time of high-load production events;

[0044] Based on the current time and the preset start time of the high-load production event, determine whether the high-load production event falls within a preset review time window, and obtain a determination result;

[0045] When the judgment result is that the high-load production event does not fall within the audit time window, the transition control phase is terminated and switched to the normal control mode;

[0046] When the judgment result is that the high-load production event falls within the audit time window, the operation of the transition control stage is maintained.

[0047] Among them, upstream load information refers to data reflecting the production intensity or wastewater discharge characteristics of upstream enterprises. Specifically, it can be information such as production plans, output forecasts or operating status of key production equipment obtained through data interfaces, manual input or prediction models. Its purpose is to perceive potential wastewater load changes in advance; high-load production events refer to specific production activities or time periods in upstream enterprises that may lead to a significant increase in wastewater discharge or pollutant concentrations, such as centralized slaughtering, large-scale cleaning or peak production of specific products. The preset start time refers to the time point when the event is planned to start; the preset audit time window can be understood as a time range for evaluating the potential impact of high-load production events on system stability. Its duration and starting point can be preset or dynamically adjusted according to factors such as system characteristics and microbial recovery speed. Judging whether the event falls within the time window is to determine whether the system is ready to switch to normal mode in the face of the upcoming high-load impact.

[0048] The solution of this application introduces a mechanism for predicting upstream load information, adding a judgment step based on future risk assessment at the critical moment when the transition control phase is about to end and the system is preparing to switch to conventional control mode. Specifically, the system first obtains information on the upstream enterprise's future production activities, specifically events that may lead to high-load emissions and their preset start times. The system then compares the current time with the preset start time of the high-load event and, based on a preset review time window, determines whether the event is about to occur and may affect the system. This forward-looking judgment enables the system to flexibly adjust subsequent strategies based on the judgment results. If the judgment result indicates that the high-load event will not occur within the review time window, it indicates that the system will not face significant external shocks in the short term. At this time, the system can safely terminate the transition control phase and switch back to conventional control mode, fully utilizing the processing capacity after microbial recovery. Conversely, if the judgment result indicates that the high-load event falls within the review time window, it means that the system is about to face a potential load shock. To avoid switching modes under possible instability, the system will choose to maintain operation in the transition control phase and continue to use a relatively conservative and stable control strategy until the potential risk period has passed. This mechanism, combined with the aforementioned safe mode exit conditions and transition control strategies, forms a more robust system recovery and operation mode. It not only ensures that the system can gradually increase its treatment capacity after microbial activity recovers, but more importantly, it adds a layer of adaptive judgment to external environmental changes at the critical point of complete recovery, avoiding secondary shocks or recovery failures caused by sudden changes in upstream loads, thereby improving the stability and reliability of the entire wastewater treatment system under complex operating conditions.

[0049] As an embodiment of the present invention, the step of determining whether the high-load production event falls within a preset review time window based on the current time and the preset start time of the high-load production event includes:

[0050] During the transition control phase, a recovery rate index is obtained to characterize the recovery rate of microorganisms in the anoxic treatment unit;

[0051] Determine the length of the audit window based on the recovery rate indicator;

[0052] Based on the current time, the preset start time of the high-load production event and the determined duration of the audit time window, it is determined whether the high-load production event falls within the audit time window.

[0053] Among them, the recovery rate index refers to a parameter used to quantify the degree or speed at which microorganisms in the anoxic treatment unit recover their denitrification activity from an inhibited state. It can be obtained by monitoring the changing trend of the nitrate removal efficiency of the anoxic treatment unit over time, or monitoring the activity of specific enzymes, or monitoring changes in the structure of the microbial community; the length of the audit time window refers to the length used to define a specific time interval, which is used to determine whether a high-load production event will overlap with a critical period for microbial recovery. It can be dynamically adjusted according to the actual recovery rate index of the microorganism, rather than being fixed.

[0054] The solution of this application obtains a real-time recovery rate indicator, representing the rate of microbial recovery within the anoxic treatment unit, during the transition control phase, thereby understanding the actual recovery progress of the microorganisms. Based on this recovery rate indicator, the length of the audit window is dynamically determined to match the actual recovery speed of the microorganisms. The faster the recovery, the shorter the window; the slower the recovery, the longer the window. A judgment is then made based on the current time, the preset start time of the high-load production event, and the length of this dynamically determined audit window. This dynamic judgment mechanism, compared to a fixed time window, can more accurately predict whether the microorganisms have recovered sufficiently to cope with the impact of the high-load event. If the high-load event is determined to fall within the dynamically adjusted audit window, it indicates that the microorganisms may not have fully recovered or are recovering slowly. In this case, the transition control phase can be maintained, and a more conservative control strategy can be continued to avoid system crashes caused by premature switching to conventional control. If it is not determined to fall within the audit window, it indicates that the microorganisms have recovered well or the high-load event occurred a long time ago, and it is safe to switch to conventional control mode. This dynamic adjustment of the audit time window, combined with safety modes, transition control, and a preliminary judgment mechanism based on high-load events, creates a more intelligent and adaptive wastewater treatment control strategy. It not only resolves the inaccurate judgment issues associated with fixed time windows, but also enables the entire system to more smoothly and efficiently respond to external disturbances during recovery from abnormal conditions, improving system stability and reliability.

[0055] As an embodiment of the present invention, the step of obtaining a recovery rate index characterizing the recovery rate of microorganisms in the anoxic treatment unit includes:

[0056] Obtaining the nitrate concentrations at the inlet and outlet of the anoxic treatment unit to form inlet concentration time series data and outlet concentration time series data;

[0057] Determining differential concentration time series data representing nitrate removal efficiency of the anoxic treatment unit based on the inlet concentration time series data and the outlet concentration time series data;

[0058] Determine the changing trend of the differential concentration time series data within the preset time window, and use the changing trend as the recovery rate indicator.

[0059] Among them, the inlet concentration time series data and the outlet concentration time series data refer to the series of nitrate concentration values ​​at the inlet and outlet of the anoxic treatment unit obtained at different sampling times, which can be obtained by using an online nitrate sensor or laboratory analysis after regular sampling. The differential concentration time series data refers to a numerical sequence calculated based on the inlet concentration time series data and the outlet concentration time series data, which reflects the nitrate removal capacity of the anoxic treatment unit at different times. Specifically, it can be obtained by subtracting the values ​​of the inlet concentration time series data and the outlet concentration time series data at the corresponding times. The preset time window refers to a continuous time interval used to analyze the changing characteristics of the differential concentration time series data, and its duration can be set based on actual process operation experience or historical data analysis results. The change trend refers to the overall change direction or state of the differential concentration time series data within the preset time window, such as rising, falling or relatively stable. The recovery rate index refers to a parameter or state identifier used to quantify or qualitatively describe the recovery speed of microbial denitrification activity in the anoxic treatment unit.

[0060] This solution monitors the nitrate concentrations of the influent and effluent of the anoxic treatment unit in real-time or near-real-time, generating time-series data on differential concentrations that reflect nitrate removal effectiveness. This differential concentration directly reflects the level of microbial denitrification activity. By analyzing the changing trends of this differential concentration data over a predetermined period, it is possible to determine whether microbial activity is increasing, decreasing, or remaining stable, as well as the rate of recovery. For example, a sustained increase in differential concentration indicates enhanced removal capacity and recovery of microbial activity. Using this trend as a quantitative or qualitative indicator of recovery rate provides a direct and dynamic basis for determining the subsequent audit window. This method of assessing microbial recovery based on the changing trends of actual process parameters (nitrate removal efficiency) is more accurate than relying solely on fixed timeframes or empirical judgment. The acquired recovery rate indicator is used to determine the duration of the audit window, allowing it to be adjusted based on the actual microbial recovery status. When the recovery rate is rapid, the audit window can be shortened; when the recovery rate is slow, the audit window can be extended. In this way, the audit time window determined based on the recovery rate metric can more accurately reflect the time required for microorganisms to reach a stable state, making subsequent determinations of whether high-load production events fall within this time window more reliable. This avoids the problems caused by improperly set audit time windows, such as premature termination of the transition control phase (microorganisms not fully recovered, insufficient capacity to cope with high loads) or late termination (unnecessarily prolonging transition control and affecting efficiency). In this way, this solution provides key technical support for a smooth transition from safe mode to conventional control mode, improving the overall wastewater treatment system's ability to cope with load fluctuations and operational stability.

[0061] As an embodiment of the present invention, the step of determining the change trend of the differential concentration time series data within a preset time window includes:

[0062] Dividing the preset time window into a first sub-window and a second sub-window;

[0063] Determine, based on the differential concentration time series data, a first mean value within the first sub-window and a second mean value within the second sub-window;

[0064] Based on the comparison relationship between the first mean and the second mean, a change trend is determined.

[0065] wherein, the preset time window refers to a specific time period for observing and analyzing the differential concentration time series data; wherein, the first sub-window and the second sub-window refer to two time periods into which the preset time window is divided, which may be continuous or discontinuous; wherein, the differential concentration time series data refers to a data sequence in which the difference in nitrate concentration at the inlet and outlet of the anoxic treatment unit changes with time; wherein, the first mean refers to the average value of the differential concentration time series data in the first sub-window, which may be obtained by summing the data points in the time period and dividing by the number of data points; wherein, the second mean refers to the average value of the differential concentration time series data in the second sub-window, which may be obtained by summing the data points in the time period and dividing by the number of data points; wherein, the comparative relationship refers to the size or relative difference relationship between the first mean and the second mean; wherein, the change trend refers to the overall upward, downward or stable tendency of the differential concentration time series data in the preset time window.

[0066] The solution of the present application is to divide the preset time window into a first sub-window and a second sub-window, thereby dividing the observation time period into two parts, front and back. Based on the differential concentration time series data, the first mean in the first sub-window and the second mean in the second sub-window are calculated respectively. By calculating the mean, the random fluctuations of the data in the short term can be effectively filtered out, and a stable estimate of the data level in each sub-window can be obtained. Based on the comparative relationship between the first mean and the second mean, the trend of change is determined. By comparing the average levels of the two time periods, it can be directly judged whether the differential concentration time series data is rising, falling or remaining stable as a whole within the preset time window. This method provides an objective and quantitative way to evaluate the changes in the nitrate removal efficiency of the anoxic treatment unit over time, so that the recovery rate index that characterizes the microbial recovery rate can be accurately obtained. In this way, the present application can extract key information reflecting microbial activity from the original concentration data, providing a reliable basis for subsequent wastewater treatment regulation.

[0067] As an embodiment of the present invention, the step of determining the change trend based on the comparison relationship between the first mean and the second mean includes:

[0068] Set a preset trend judgment threshold;

[0069] Comparing the difference between the second mean and the first mean with a preset trend judgment threshold to obtain a comparison result;

[0070] According to the comparison result, the change trend is determined, wherein, when the difference between the second mean and the first mean is greater than the preset trend judgment threshold, the change trend is determined to be increasing; when the difference between the second mean and the first mean is less than a negative preset trend judgment threshold, the change trend is determined to be weakening; otherwise, the change trend is determined to be stable.

[0071] Among them, the preset trend judgment threshold refers to a reference value used to distinguish the change amplitude of the difference concentration time series data within the preset time window, which can be set according to historical operation data, expert experience or real-time monitoring of system fluctuations; the comparison result refers to the judgment of the relationship between the difference between the second mean and the first mean relative to the preset trend judgment threshold and its negative value, which can be obtained through numerical comparison operations; the change trend refers to the overall change direction and amplitude judgment of the difference concentration time series data within the preset time window. Enhancement indicates that the nitrate removal efficiency has been significantly improved, weakening indicates that the nitrate removal efficiency has been significantly decreased, and stability indicates that the nitrate removal efficiency has not changed significantly.

[0072] The solution of the present application sets a preset trend judgment threshold through the above steps, and the threshold is used to quantitatively judge whether the change amplitude of the difference concentration time series data within the preset time window is significant. Specifically, on the basis of calculating the first mean and the second mean, the difference between the second mean and the first mean is calculated, and the difference is compared with the preset trend judgment threshold. If the difference is greater than the positive threshold, it indicates that the average removal efficiency in the latter sub-window is significantly improved relative to the previous sub-window, thereby determining that the change trend is enhanced. If the difference is less than the negative threshold, it indicates that the average removal efficiency has decreased significantly, and the change trend is determined to be weakened. If the difference is between the negative threshold and the positive threshold, it is considered that the change is not significant, and the change trend is determined to be stable. This method effectively filters out the common random fluctuations in the wastewater treatment process by introducing a threshold, avoids misjudging the trend due to small fluctuations, and makes the assessment of the recovery rate of microorganisms in the anoxic treatment unit more accurate and robust. This accurate trend judgment, as a recovery rate indicator, can more reliably reflect the actual degree of recovery of microbial activity, provide key information for subsequent judgment on whether the conditions for exiting the safety mode are met, and improve the reliability of the entire wastewater treatment regulation and correction method.

[0073] As an embodiment of the present invention, the step of setting a preset trend determination threshold includes:

[0074] During the transition control phase, the fluctuation index of the difference concentration time series data within the preset time window is obtained;

[0075] Determine the trend judgment threshold based on the volatility index.

[0076] Specifically, the transition control phase refers to an intermediate stage after exiting safety mode, replacing the immediate return to normal control mode. Its purpose is to smoothly transition the system from low-load safety mode to normal control mode based on real-time signals, preventing system instability due to sudden load changes. The differential concentration time series data refers to the time-varying difference in nitrate concentration between the inlet and outlet of the anoxic treatment unit. This data directly reflects the nitrate removal capacity or efficiency of the anoxic treatment unit at different moments. The preset time window refers to a continuous time range used to analyze the trend or degree of fluctuation of the differential concentration time series data. Its length can be set based on the actual system response characteristics and monitoring frequency. The fluctuation index is a numerical value used to quantify the severity of fluctuations in the differential concentration time series data within the preset time window. It can be represented by statistics such as standard deviation, variance, range, and mean absolute deviation. The trend judgment threshold is a critical value used to determine the trend (increasing, weakening, or stabilizing) of the differential concentration time series data within the preset time window. This judgment is made by comparing the data change with the threshold.

[0077] Through the above method, the solution of the present application can realize the following working principle: in the transition control stage, the system obtains the fluctuation index of the differential concentration time series data within the preset time window, and determines the trend judgment threshold based on the fluctuation index. This method no longer uses a fixed threshold, but dynamically adjusts the threshold size according to the fluctuation situation during the actual operation of the system. When the system fluctuation is large, the calculated fluctuation index will be higher, and the trend judgment threshold determined accordingly will also increase accordingly. This can effectively filter out the impact of normal system fluctuations on trend judgment and avoid misjudging non-restorative fluctuations as changes in recovery rate. Conversely, when the system runs smoothly and the fluctuation index is low, the determined trend judgment threshold will also decrease, making the trend judgment more sensitive to subtle changes in the recovery rate of microorganisms. By adaptively adjusting the trend judgment threshold according to real-time fluctuations, the accuracy of trend judgment of differential concentration time series data changes is improved. This accurate trend judgment can more reliably reflect the actual recovery rate of microorganisms in the anoxic treatment unit, providing a more solid foundation for the subsequent determination of the audit time window length based on the recovery rate indicator, so that the duration of the transition control phase can more accurately adapt to the actual recovery process of the microorganisms and external load changes, and ultimately achieve a smooth and efficient switching of the system from safe mode to normal mode, avoiding system instability or recovery delays due to misjudgment.

[0078] As an embodiment of the present invention, the step of determining a trend judgment threshold based on a volatility index includes:

[0079] Obtain the mean value of the difference concentration time series data within the preset time window as the average removal efficiency indicator;

[0080] Get the adjusted volatility sensitivity coefficient;

[0081] Determine the trend judgment threshold based on the adjusted volatility sensitivity coefficient;

[0082] The adjusted volatility sensitivity coefficient is determined according to the following formula:

[0083] k_adj = k_max - (k_max - k_min) * f

[0084] Wherein, k_adj is the adjusted fluctuation sensitivity coefficient, k_max is a preset maximum fluctuation sensitivity coefficient, k_min is a preset minimum fluctuation sensitivity coefficient, and f is an efficiency level factor; the efficiency level factor f is determined according to the ratio of the average removal efficiency index to a preset reference efficiency level, and when the ratio is greater than 1, f takes the value of 1, otherwise f takes the value of the ratio;

[0085] The trend judgment threshold is determined according to the following formula:

[0086] h = k_adj * S + Th_base

[0087] Among them, Th is the trend judgment threshold, S is the volatility index, and Th_base is a preset basic judgment threshold.

[0088] Among them, the average removal efficiency index refers to the average value of the difference concentration time series data within the preset time window, and its purpose is to quantify the average denitrification effect of the anoxic treatment unit over a period of time; the adjusted fluctuation sensitivity coefficient k_adj refers to the coefficient used to adjust the influence of the fluctuation degree S on the trend judgment threshold Th, and its value is dynamically adjusted according to the average removal efficiency index, and its purpose is to make the sensitivity of the threshold to fluctuations adapt to different system efficiency levels; the maximum fluctuation sensitivity coefficient k_max refers to the preset k_adj upper limit value, and its purpose is to limit the maximum possible value of k_adj; the minimum fluctuation sensitivity coefficient k_min refers to the preset k_adj lower limit value, and its purpose is to limit the minimum possible value of k_adj; the efficiency level factor f refers to a factor between 0 and 1, which reflects the current average removal efficiency relative to the reference efficiency The purpose of the reference efficiency level is to map the average removal efficiency to a proportional factor for adjusting the fluctuation sensitivity coefficient; the reference efficiency level refers to a preset benchmark value used to measure the current level of average removal efficiency, and its purpose is to provide a reference for the calculation of the efficiency level factor f; the trend judgment threshold Th refers to the threshold used to judge the trend of changes in the difference concentration time series data, and its value comprehensively considers the degree of fluctuation and the average removal efficiency, and its purpose is to provide a dynamically adjusted judgment standard; the fluctuation degree index S refers to the fluctuation size of the difference concentration time series data within the preset time window, for example, it can be represented by the standard deviation or range, and its purpose is to quantify the degree of discreteness of the data sequence; the basic judgment threshold Th_base refers to a preset constant, and its purpose is to ensure that Th has a minimum benchmark value to avoid the threshold being too low when the fluctuation is extremely small.

[0089] The solution of the present application dynamically adjusts the trend judgment threshold by introducing the average removal efficiency index and combining it with the fluctuation degree index. First, the average removal efficiency over a period of time is calculated, which reflects the overall denitrification capacity of the system. Then, the efficiency level factor f is determined based on the ratio of the average removal efficiency to the reference efficiency level. When the average removal efficiency is high, f approaches 1; when the average removal efficiency is low, f approaches the ratio. Use f to adjust the fluctuation sensitivity coefficient k_adj. The formula k_adj = k_max - (k_max - k_min) * f means that when f is larger (the higher the average efficiency), k_adj is smaller, and the impact of fluctuations on the threshold is weakened; when f is smaller (the lower the average efficiency), k_adj is larger, and the impact of fluctuations on the threshold is enhanced. Finally, the trend judgment threshold is calculated according to Th = k_adj * S + Th_base. In this way, the threshold not only depends on the current fluctuation degree S, but also reflects the current average removal efficiency level through k_adj. This mechanism ensures that when the system recovers well (high average performance), even with some fluctuations, the threshold remains constant, preventing misjudgments. Meanwhile, when the system recovers slowly (low average performance), even with minor fluctuations, the threshold is more sensitive to subtle changes and promptly captures signs of recovery. By introducing average removal efficiency for adjustment, the threshold is more adaptable to varying system states, improving judgment accuracy.

[0090] like Figure 2 A food wastewater treatment control system is shown, the system comprising:

[0091] The trial pulse dosing module 201 is used to add a preset pulse amount of internal carbon source liquid to the internal reflux path as a trial pulse based on a fixed low flow rate dosing at a preset trial period during the safe mode operation;

[0092] A trial response rate acquisition module 202 is configured to acquire an actual decreasing rate of the nitrate concentration in the internal reflux path after the trial pulse is added, as a trial response rate;

[0093] A comparison module 203 is configured to compare the probe response rate with a preset recovery reference rate to obtain a comparison result;

[0094] The mode switching control module 204 is configured to terminate the safety mode and return to the normal control mode of controlling the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path when the comparison result satisfies the preset exit condition.

[0095] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A method for controlling food wastewater treatment, applied to a wastewater treatment system, wherein the wastewater treatment system includes an anoxic treatment unit for denitrification and an aerobic treatment unit for nitrification, and is provided with an internal reflux path for returning the effluent of the aerobic treatment unit to the anoxic treatment unit, characterized in that: The method comprises: During the safe mode operation, a preset pulse amount of internal carbon source liquid is added to the internal reflux path at a preset trial period and at a fixed low flow rate as a trial pulse; After the probe pulse is added, obtaining an actual decreasing rate of the nitrate concentration in the internal reflux path as a probe response rate; Comparing the trial response rate with a preset recovery reference rate to obtain a comparison result; When the comparison result satisfies a preset exit condition, the safety mode is terminated and the normal control mode of controlling the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path is restored; When the comparison result satisfies a preset exit condition, the step of terminating the safety mode and resuming the normal control mode of controlling the internal carbon source liquid addition according to the real-time detection signal of the nitrate concentration in the internal reflux path comprises: Initiating a transition control phase instead of directly reverting to the normal control mode; In the transient control phase, determining a reference injection speed that increases gradually with the time progress of the transient control phase; In the transition control stage, a feedback injection acceleration is determined according to a deviation between the real-time nitrate concentration in the internal reflux path and a target value; Determining the dosing speed of the internal carbon source liquid based on the reference dosing speed and the feedback dosing speed and according to a control weight that increases over time; After the transition control phase meets a preset end condition, the transition control phase is terminated and the control mode is switched to the normal control mode.

2. A food wastewater treatment control method according to claim 1, characterized in that, After the transition control phase meets a preset end condition, the step of terminating the transition control phase and switching to the normal control mode includes: Acquiring upstream load information representing future production activities of upstream enterprises, wherein the upstream load information includes a preset start time of a high-load production event; Based on the current time and the preset start time of the high-load production event, determining whether the high-load production event falls within a preset review time window, and obtaining a determination result; When the judgment result is that the high-load production event does not fall within the review time window, terminating the transition control phase and switching to the normal control mode; When the judgment result is that the high-load production event falls within the audit time window, the operation of the transition control phase is maintained.

3. A food wastewater treatment control method according to claim 2, characterized in that, The step of determining whether the high-load production event falls within a preset review time window based on the current time and the preset start time of the high-load production event includes: During the transition control phase, a recovery rate index is obtained that characterizes the recovery rate of microorganisms in the anoxic treatment unit; Determining the duration of the audit time window based on the recovery rate indicator; Based on the current time, the preset start time of the high-load production event and the determined duration of the audit time window, it is determined whether the high-load production event falls within the audit time window.

4. A food wastewater treatment control method according to claim 3, characterized in that, The step of obtaining a recovery rate index representing the recovery rate of microorganisms in the anoxic treatment unit includes: Acquiring the nitrate concentrations at the inlet and outlet of the anoxic treatment unit to form inlet concentration time series data and outlet concentration time series data; Determining differential concentration time series data characterizing nitrate removal efficiency of the anoxic treatment unit based on the inlet concentration time series data and the outlet concentration time series data; Determine a change trend of the difference concentration time series data within a preset time window, and use the change trend as the recovery rate indicator.

5. A food wastewater treatment and control method according to claim 4, characterized in that, The step of determining the change trend of the differential concentration time series data within a preset time window includes: Dividing the preset time window into a first sub-window and a second sub-window; Determining a first mean value within the first sub-window and a second mean value within the second sub-window based on the differential concentration time series data; The change trend is determined based on a comparison relationship between the first mean and the second mean.

6. A food wastewater treatment and control method according to claim 5, characterized in that: The step of determining the change trend based on the comparison relationship between the first mean and the second mean includes: Set a preset trend judgment threshold; comparing the difference between the second mean and the first mean with the preset trend determination threshold to obtain a comparison result; Based on the comparison result, the change trend is determined, wherein when the difference between the second mean and the first mean is greater than the preset trend judgment threshold, the change trend is determined to be increasing; when the difference between the second mean and the first mean is less than the negative preset trend judgment threshold, the change trend is determined to be weakening; otherwise, the change trend is determined to be stable.

7. A food wastewater treatment and control method according to claim 6, characterized in that: The step of setting a preset trend judgment threshold comprises: In the transition control stage, obtaining a fluctuation index of the difference concentration time series data within a preset time window; Based on the fluctuation degree index, the trend judgment threshold is determined.

8. A food wastewater treatment and control method according to claim 7, characterized in that: The step of determining the trend judgment threshold based on the fluctuation degree index includes: Obtaining the average of the difference concentration time series data within the preset time window as an average removal efficiency indicator; Get the adjusted volatility sensitivity coefficient; The trend judgment threshold is determined based on the adjusted fluctuation sensitivity coefficient.

9. A food wastewater treatment control system, used to implement a food wastewater treatment control method according to any one of claims 1 to 8, characterized in that: The system includes: a trial pulse dosing module, configured to, during operation in the safe mode, dosing a preset pulse amount of the internal carbon source liquid into the internal reflux path at a preset trial period and on the basis of a fixed low flow rate as a trial pulse; a probe response rate acquisition module, configured to acquire, after the probe pulse is added, an actual decreasing rate of the nitrate concentration in the internal reflux path as a probe response rate; A comparison module, configured to compare the probe response rate with a preset recovery reference rate to obtain a comparison result; The mode switching control module is used to terminate the safety mode and restore to the normal control mode of controlling the addition of the internal carbon source liquid according to the real-time detection signal of the nitrate concentration in the internal reflux path when the comparison result meets the preset exit condition.

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