Food wastewater treatment regulation and control method

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a food wastewater treatment regulation and control method which comprises the following steps: during a safe mode operation period, on the basis of fixed low-flow addition, adding internal carbon source liquid with a preset pulse quantity into an internal reflux path as a tentative pulse according to a preset tentative period; after the tentative pulse is added, the actual decreasing rate of the nitrate concentration in the internal backflow path is obtained and serves as the tentative response rate; comparing the tentative response rate with a preset recovery reference rate to obtain a comparison result; the microorganism activity recovery condition is judged by adding the tentative pulse and monitoring the response in the safety mode, the safety mode is safely and stably quitted in combination with transition control and upstream load prediction, and the time for quitting the safety mode can be intelligently judged according to the actual activity recovery condition of microorganisms, so that the safety mode quitting time is shortened. And blind exit or long-time maintenance of a conservative mode is avoided.

Description

[0001] This application is a divisional application of the application with application number 202511109996.4, filed on August 8, 2025, and titled "Food wastewater treatment regulation method and system". TECHNICAL FIELD

[0002] The present application relates to the technical field of wastewater treatment, and in particular to a food wastewater treatment regulation method and system. BACKGROUND

[0003] Wastewater treatment, especially wastewater treatment systems using biological denitrification processes (such as anoxic-oxic, A / O process), highly depends on the activity and stability of microorganisms for its treatment effect. In the A / O process, the denitrification process in the anoxic section requires sufficient carbon source as an electron donor to reduce nitrate to nitrogen gas. However, in actual operation, due to fluctuations in the quality of the influent, especially changes in the carbon source content, the microbial activity in the anoxic section is often inhibited, the denitrification efficiency is reduced, and thus the denitrification effect of the entire system is affected, leading to excessive total nitrogen in the effluent. When the system identifies that the microbial activity in the anoxic treatment unit is inhibited, in order to avoid further deterioration of the treatment effect or system collapse, certain measures need to be taken, such as entering a safety mode. In the safety mode, some conservative control strategies may be taken, such as adding carbon source at a fixed low flow rate, to maintain basic microbial activity.

[0004] However, how to determine whether the microbial activity has recovered enough to exit the safety mode and return to the regular control mode is a challenge faced by the prior art. Blindly exiting the safety mode may lead to system collapse again, while maintaining in the conservative safety mode for a long time may affect the treatment efficiency and economy. The prior art lacks an effective method that can intelligently determine the system recovery state according to the actual response of the microorganisms, and safely and smoothly exit the safety mode.

[0005] In view of the above problems, the prior art needs to be improved. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the prior art and provide a food wastewater treatment regulation method and system.

[0007] In a first aspect, the present application provides a food wastewater treatment regulation method applied to a wastewater treatment system, the wastewater treatment system comprising an anoxic treatment unit for denitrification and an oxic treatment unit for nitrification, and being provided with an internal reflux path for refluxing the effluent of the oxic treatment unit to the anoxic treatment unit, the method comprising: During the safe mode operation, a preset pulse amount of internal carbon source liquid is added to the internal reflux path as a test pulse in a preset test period on the basis of fixed low flow addition; After the test pulse addition, an actual reduction rate of nitrate concentration in the internal reflux path is obtained as a test response rate; The test response rate is compared with a preset recovery reference rate to obtain a comparison result; When the comparison result meets a preset exit condition, the safe mode is terminated, and a normal control mode of controlling the internal carbon source liquid addition according to a real-time detection signal of the nitrate concentration in the internal reflux path is recovered.

[0008] The core innovation of the present application is that the periodic test pulse addition and the response evaluation mechanism based on the nitrate reduction rate are introduced in the safe mode, so that the dynamic monitoring and judgment of the microbial activity recovery in the anoxic treatment unit are realized, the exit time of the safe mode is intelligently determined according to the actual recovery state, the waste of carbon source is avoided, and the effect of promoting the stable recovery of the system is achieved.

[0009] In a second aspect, a food wastewater treatment regulation system is provided, which comprises: A test pulse addition module is configured to add a preset pulse amount of internal carbon source liquid to the internal reflux path as a test pulse in a preset test period on the basis of fixed low flow addition during the safe mode operation; A test response rate acquisition module is configured to obtain an actual reduction rate of nitrate concentration in the internal reflux path as a test response rate after the test pulse addition; A comparison module is configured to compare the test response rate with a preset recovery reference rate to obtain a comparison result; A mode switching control module is configured to terminate the safe mode and recover to a normal control mode of controlling the internal carbon source liquid addition according to a real-time detection signal of the nitrate concentration in the internal reflux path when the comparison result meets a preset exit condition.

[0010] Compared with the prior art, the present application has the following beneficial effects: The microbial activity recovery is judged by adding a test pulse and monitoring the response in the safe mode, and the safe mode is safely and smoothly exited in combination with the transition control and upstream load prediction, which has the advantages of intelligently judging the exit time of the safe mode according to the actual activity recovery of the microorganisms, avoiding blind exit or long-term maintenance of the conservative mode. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The present application is a method flowchart.

[0012] Figure 2 The system structure diagram of the present application.

[0013] In the figure: 201, tentative pulse adding module; 202, tentative response rate acquisition module; 203, comparison module; 204, mode switching control module. DETAILED DESCRIPTION

[0014] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0015] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0016] When the microbial activity in the anoxic treatment unit of the conventional existing wastewater treatment system is inhibited, the system enters the safety mode and uses a fixed low flow rate to add internal carbon source liquid. This method cannot dynamically adjust the carbon source dosage according to the actual recovery of the microorganisms, and there is a problem of mismatch between the carbon source dosage and the microbial demand. This may cause slow recovery of the microorganisms, prolong the running time of the safety mode, or excessive addition of the carbon source, resulting in waste.

[0017] For example, assume a wastewater treatment system whose anoxic treatment unit has a significant decrease in microbial activity due to fluctuations in the carbon source of the influent or toxic substance shocks, and the system identifies this state and enters a safety mode. In this safety mode, the system adds internal carbon source liquid to the internal reflux path at a preset fixed low flow rate. However, the recovery of microorganisms is a dynamic process, and their demand for carbon source is not constant. If the recovery of microorganisms is slow, the fixed low flow rate may not be sufficient to effectively stimulate the increase in activity; if the recovery of microorganisms accelerates, the fixed low flow rate may be conservative and fail to fully utilize the carbon source to accelerate recovery. This fixed addition strategy cannot adapt to the dynamic changes in demand during the recovery process of microorganisms. If the above problems are not solved, the wastewater treatment system will be in a state of low efficiency after the microbial activity is inhibited for a long time. Fixed low flow rate addition of carbon source may cause the recovery process of microorganisms to be slow, affect the overall denitrification efficiency, and increase the treatment cost. At the same time, due to the inability to accurately judge the degree of microbial recovery, the timing of the system exiting the safety mode is difficult to grasp, which may lead to unstable treatment effect if it exits too early, or unnecessary carbon source consumption and increased operating costs if it exits too late.

[0018] To this end, the present application is a food wastewater treatment control method as shown in Figure 1 A food wastewater treatment control method is applied to a wastewater treatment system, which includes an anoxic treatment unit for denitrification and an aerobic treatment unit for nitrification, and is provided with an internal reflux path for refluxing the effluent of the aerobic treatment unit to the anoxic treatment unit. The wastewater treatment system can enter a safety mode when it identifies that the microbial activity in the anoxic treatment unit is inhibited, and in the safety mode, internal carbon source liquid is added to the internal reflux path at a fixed low flow rate. The method comprises: During the operation in the safety mode, a preset trial period is set, and a preset pulse amount of internal carbon source liquid is added to the internal reflux path as a trial pulse on the basis of the fixed low flow rate addition; After the trial pulse addition, the actual reduction rate of nitrate concentration in the internal reflux path is obtained as a trial response rate; The trial response rate is compared with a preset recovery reference rate to obtain a comparison result; When the comparison result meets a preset exit condition, the safety mode is terminated, and the system returns to a normal control mode in which the addition of internal carbon source liquid is controlled according to the real-time detection signal of the nitrate concentration in the internal reflux path.

[0019] The safety mode refers to a special running state of the system when it is identified that the microbial activity in the anoxic treatment unit is inhibited, and the purpose is to protect the system stability and avoid further deterioration of microbial activity. The preset trial period refers to the time interval for trial pulse addition during the safety mode running, which can be set according to the system scale, wastewater characteristics or experience, and is mainly used to periodically detect the recovery of microorganisms. The preset pulse amount refers to the volume or flow rate of the internal carbon source liquid that is additionally added in each trial period, which can be set according to the system capacity and expected response strength, and is mainly used to apply a controllable stimulus to the microorganisms. The trial response rate refers to the actual decrease speed of nitrate concentration in the internal reflux path after the addition of the trial pulse, which reflects the immediate utilization ability of microorganisms to the additional carbon source, and is mainly used to quantitatively evaluate the recovery degree of microbial activity. The preset recovery reference rate refers to the minimum nitrate decrease rate threshold for judging whether the microbial activity has recovered enough to exit the safety mode, which can be set according to the system design standard or historical operation data, and is mainly used to provide an objective recovery judgment standard. The preset exit condition refers to the logical condition for judging when to terminate the safety mode and restore the normal control, which is usually based on the comparison result of the trial response rate and the recovery reference rate, and is mainly used to realize the intelligent exit of the safety mode. The normal control mode refers to the way of controlling the addition of internal carbon source liquid according to the real-time detection signal of nitrate concentration in the internal reflux path when the system is in normal running state, and the purpose is to maintain efficient and stable denitrification effect.

[0020] The solution of the present application realizes its function in the following way: when the wastewater treatment system identifies that the microbial activity in the anoxic treatment unit is inhibited and enters the safety mode, the system first maintains a fixed low flow rate of internal carbon source liquid addition to provide a basic carbon source. On this basis, the method additionally adds a preset pulse amount of internal carbon source liquid according to a preset trial period, and the pulse addition serves as a trial of microbial activity. After the trial pulse is added, the system obtains the actual reduction rate of nitrate concentration in the internal reflux path, which represents 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 a preset recovery reference rate. The comparison result is used to determine whether the microbial activity has recovered to the extent that the safety mode can be exited. When the comparison result meets the preset exit condition, the system terminates the operation of the safety mode and switches back to the regular 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. The whole process forms a closed loop, dynamically adjusts the duration of the safety mode through periodic trial and response evaluation, ensures timely switching to efficient regular control after the microorganisms recover, and avoids unnecessary inefficient operation and carbon source consumption.

[0021] In some preferred embodiments, the present application is implemented as follows: when the system enters the safety mode, the internal carbon source liquid is added at a fixed flow rate per hour. At the same time, the system sets a trial period, for example every 30 minutes. At the beginning of each trial period, the system additionally adds a preset pulse amount of internal carbon source liquid on the basis of the fixed low flow rate, for example, instantaneously increases the flow rate and maintains it for 1 minute. Within a period of time after the pulse addition ends, for example, within the next 5 minutes, the system continuously monitors the change of the nitrate concentration in the internal reflux path and calculates the average reduction rate of the nitrate concentration in this period of time as the trial response rate. The system presets a recovery reference rate, for example, a reduction of 0.5 mg / L of nitrate concentration per minute. The system compares the calculated trial response rate with the recovery reference rate. The preset exit condition can be set as the trial response rate being greater than or equal to the recovery reference rate. When the comparison result meets this condition, the system determines that the microbial activity has recovered, immediately terminates the safety mode, and switches to the regular control mode based on the real-time nitrate concentration feedback, for example, uses a PID controller to adjust the carbon source addition flow rate according to the deviation of the nitrate concentration from the target value.

[0022] As an embodiment of the present application, when the comparison result meets the preset exit condition, the step of terminating the safety mode and recovering to the regular 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 includes: starting a transition control phase to replace the direct recovery to the regular control mode; a reference dosing speed that increases with time during the transition control phase; a feedback dosing speed that is determined based on the deviation of the real-time nitrate concentration in the internal return path from a target value during the transition control phase; a final dosing speed of the internal carbon source liquid is determined based on the reference dosing speed and the feedback dosing speed, and according to a control weight that increases with time; the transition control phase is terminated and the system switches to the regular control mode after the preset ending condition is met.

[0023] The transition control phase refers to an intermediate operating state between the safety mode and the regular control mode, and its purpose is to provide a buffer period to enable the system to smoothly recover from the inhibited state to the normal operating state. Time-based phase division or system state-based judgment can be used to define the duration of the transition control phase. The reference dosing speed refers to a gradually increasing carbon source dosing amount or dosing rate during the transition control phase, which is preset without considering real-time feedback signals. Its purpose is to provide a basic, time-increasing carbon source supply for the recovery of active microorganisms. Linear, exponential, or other increasing functions can be used to determine the reference dosing speed. The feedback dosing speed refers to a quantity calculated by a feedback control algorithm based on the difference between the real-time monitored nitrate concentration in the internal return path and the expected target value during the transition control phase, which is used to correct the reference dosing speed. Its purpose is to finely adjust the carbon source dosing according to the actual denitrification demand. PID control, fuzzy control, or other feedback control algorithms can be used to achieve the feedback dosing speed. The control weight refers to a parameter used to balance the influence of the reference dosing speed and the feedback dosing speed when determining the final carbon source dosing speed. The weight increases with time, meaning that the influence of feedback control on the total dosing speed gradually increases in the later stage of the transition phase. A function that increases from a lower value to a higher value with time can be used to determine the control weight. The preset ending condition refers to a series of pre-set standards used to determine when the transition control phase ends and switches to the regular control mode. These standards can be based on time, system performance indicators, or external events, etc.

[0024] The scheme of the present application does not immediately switch to the normal control mode after meeting the safety mode exit condition, but starts a transition control phase. In the transition control phase, the carbon source dosage consists of two parts: one part is the baseline dosage speed that gradually increases with time, which provides a basic carbon source supply for the gradually recovered active microorganisms; the other part is the feedback dosage speed calculated according to the deviation of the nitrate concentration in the internal reflux path from the target value, which enables the system to make real-time adjustments according to the actual denitrification demand. In the process of the transition control phase, the influence of the feedback dosage speed in the total dosage speed (reflected by the increasing control weight) gradually increases, which means that the control strategy gradually shifts from the preset recovery path to the feedback adjustment based on real-time performance. Only when the transition control phase meets the preset end condition, indicating that the system has reached a certain level of stability or recovery, the final switch to the normal control mode based on real-time nitrate concentration feedback is made. This phased and gradual control strategy avoids the system shock and instability caused by direct switching, ensuring the smooth operation of the wastewater treatment system and the stability of the effluent quality. Combined with the method of judging the recovery degree of microbial activity based on the trial pulse response, the present scheme can switch modes in a smooth transition way when the microbial activity is recovered enough to support the normal control, thereby effectively solving the technical problems of how to judge the appropriate recovery opportunity and realize smooth control mode switching after the microbial activity is inhibited.

[0025] As an embodiment of the present application, after the transition control phase meets the preset end condition, the step of terminating the transition control phase and switching to the normal control mode includes: obtaining upstream load information representing future production activities of an upstream enterprise, the upstream load information including 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, judging whether the high-load production event falls within a preset audit time window to obtain a judgment result; when the judgment result is that the high-load production event does not fall within the audit 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, maintaining the operation of the transition control phase.

[0026] wherein the upstream load information refers to data reflecting the production intensity or wastewater discharge characteristics of the upstream enterprise, which can be production plans, yield forecasts or the operating status of key production equipment obtained through a data interface, manual input or a prediction model, and the purpose is to anticipate potential changes in wastewater load in advance; the high-load production event refers to a specific production activity or period in the upstream enterprise that can cause a significant increase in wastewater discharge or pollutant concentration, such as concentrated slaughtering, large-scale cleaning or a peak production period of a specific product, and the preset start time refers to the time point at which the event is planned to start; the preset audit time window can be understood as a time range for evaluating the potential impact of the high-load production event on system stability, and its length and starting point can be preset or dynamically adjusted according to system characteristics, microbial recovery speed and other factors, and determining whether the event falls within the time window is to determine whether the system is ready to switch to the normal mode in the face of an upcoming high-load impact.

[0027] The scheme of the present application introduces a pre-judgment mechanism for upstream load information, which adds a judgment link based on future risk assessment at the critical moment when the transition control phase is about to end and the system is ready to switch to the normal control mode. Specifically, the system first obtains the future production activity information of the upstream enterprise, especially the event that can cause high-load discharge and its preset start time. Then, the system compares the current time with the preset start time of the high-load event and combines a preset audit time window to determine whether the event is about to occur and can affect the system. It is precisely because of this forward-looking judgment that the system can flexibly adjust the subsequent strategy according to the judgment result: if the judgment result shows that the high-load event will not occur within the audit time window, indicating that the system will not face a significant external impact in the short term, the system can safely terminate the transition control phase and switch back to the normal control mode, making full use of the treatment capacity after the microbial recovery; on the contrary, if the judgment result shows that the high-load event falls within the audit time window, meaning that the system will face a potential load impact, in order to avoid mode switching in a possible unstable state, the system will choose to maintain the operation of the transition control phase and continue to use a relatively conservative and stable control strategy until the potential risk period is over. This mechanism, combined with the aforementioned safety mode exit condition and transition control strategy, forms a more robust system recovery and operation mode. It not only ensures that the system can gradually increase the treatment capacity after the microbial activity is restored, but more importantly, it adds a layer of adaptability judgment for external environmental changes at the critical point of recovery completion, avoiding a secondary impact or recovery failure due to upstream load mutation, thereby improving the stability and reliability of the entire wastewater treatment system under complex working conditions.

[0028] As an embodiment of the present application, the step of judging whether the high-load production event falls into the preset audit time window based on the current time and the preset starting time of the high-load production event comprises: In the transition control phase, a recovery rate index representing the recovery rate of microorganisms in the anoxic treatment unit is obtained; Based on the recovery rate index, the length of the audit time window is determined; Based on the current time, the preset starting time of the high-load production event, and the determined length of the audit time window, it is judged whether the high-load production event falls into the audit time window.

[0029] The recovery rate index refers to a parameter for quantifying the degree or speed of the recovery of microorganisms in the anoxic treatment unit from the inhibited state to their denitrification activity, which can be obtained by monitoring the change trend of the removal efficiency of nitrate in the anoxic treatment unit over time, or by monitoring specific enzyme activity, or by monitoring changes in microbial community structure; the length of the audit time window refers to the length of a specific time interval used to judge whether the high-load production event overlaps with the critical period of microbial recovery, which can be dynamically adjusted according to the actual recovery rate index of the microorganisms, rather than being fixed.

[0030] The scheme of the present application obtains the recovery rate index representing the recovery rate of microorganisms in the anoxic treatment unit in real time during the transition control phase, thereby grasping the actual recovery process of the microorganisms. Based on this recovery rate index, the length of the audit time window is dynamically determined, so that the length of the audit time window can match the actual recovery speed of the microorganisms. The faster the recovery, the shorter the time window; the slower the recovery, the longer the time window. Then, based on the current time, the preset starting time of the high-load production event, and the dynamically determined length of the audit time window, the judgment is made. This dynamic judgment mechanism can more accurately predict whether the microorganisms have recovered to a state sufficient to cope with the impact when the high-load event occurs, compared to a fixed time window. If it is judged that the high-load event falls into the dynamically adjusted audit time window, it indicates that the microorganisms may not have fully recovered or the recovery speed is slow, and at this time the operation of the transition control phase is maintained, and a more conservative control strategy can be continued to be used to avoid the system from collapsing due to premature switching to the regular control. If it is judged that it does not fall into, it indicates that the microorganisms have recovered well or the high-load event occurs far away, and the regular control mode can be safely switched to. This dynamic adjustment of the audit time window, combined with the safety mode, the transition control, and the preliminary judgment mechanism based on the high-load event, forms a more intelligent and adaptive wastewater treatment regulation strategy. It not only solves the problem of inaccurate judgment caused by the fixed time window, but also enables the entire system to more smoothly and efficiently cope with external disturbances during the recovery from abnormal state to normal operation, thereby improving the stability and reliability of the system.

[0031] As an embodiment of the present application, the step of obtaining the recovery rate indicator representing the recovery rate of the microorganisms in the anoxic treatment unit comprises: obtaining the nitrate concentration at the inlet and the outlet of the anoxic treatment unit respectively, to form the inlet concentration time series data and the outlet concentration time series data; based on the inlet concentration time series data and the outlet concentration time series data, determining the difference concentration time series data representing the nitrate removal efficiency of the anoxic treatment unit; determining the change trend of the difference concentration time series data within a preset time window, and taking the change trend as the recovery rate indicator.

[0032] Wherein, the inlet concentration time series data and the outlet concentration time series data refer to the sequence of nitrate concentration values at the inlet and the outlet of the anoxic treatment unit obtained at different sampling times, which can be obtained by online nitrate sensors or laboratory analysis after periodic sampling. The difference concentration time series data refers to the sequence of values reflecting the nitrate removal capacity of the anoxic treatment unit at different times calculated from the inlet concentration time series data and the outlet concentration time series data, which can be obtained by subtracting the values of the inlet concentration time series data and the outlet concentration time series data at the corresponding time. The preset time window refers to a continuous time interval for analyzing the change characteristics of the difference concentration time series data, the length of which can be set according to actual process operation experience or historical data analysis results. The change trend refers to the overall change direction or state of the difference concentration time series data within the preset time window, such as rising, falling or relatively stable. The recovery rate indicator refers to a parameter or state identifier for quantitatively or qualitatively describing the recovery speed of the denitrification activity of the microorganisms in the anoxic treatment unit.

[0033] The scheme obtains the difference concentration time series data reflecting the nitrate removal effect by monitoring the nitrate concentration of the water entering and exiting the anoxic treatment unit in real time or quasi-real time. The difference concentration directly reflects the level of microbial denitrification activity. By analyzing the change trend of this difference concentration data within a predetermined time, it can be determined whether the microbial activity is increasing, decreasing, or remaining stable, as well as the speed of recovery. For example, a continuous rise in difference concentration indicates that the removal capacity is increasing and the microbial activity is recovering. Using this change trend as a quantitative or qualitative indicator of recovery rate provides a direct and dynamic basis for subsequent determination of the audit time window. This method of evaluating the recovery status of microorganisms based on the change trend of actual process parameters (nitrate removal efficiency) is more accurate than simply relying on fixed time or empirical judgment. Applying the obtained recovery rate indicator to determine the length of the audit time window allows the audit time window to be adjusted according to the actual recovery of microorganisms. When the recovery rate is fast, the audit time window can be shortened appropriately; when the recovery rate is slow, the audit time window can be extended appropriately. In this way, the audit time window determined based on the recovery rate indicator can more accurately reflect the time required for microorganisms to reach a stable state, making the subsequent judgment of whether a high-load production event falls within the time window more reliable. This avoids the problem of the transition control phase ending too early (microorganisms have not fully recovered, and the ability to cope with high load is insufficient) or too late (unnecessarily prolonging the transition control, affecting efficiency) due to improper setting of the audit time window. In this way, the scheme provides key technical support for a smooth transition from the safety mode to the regular control mode, improving the ability of the entire wastewater treatment system to cope with load fluctuations and operational stability.

[0034] As an embodiment of the present application, the step of determining the change trend of the difference concentration time series data within the predetermined time window includes: dividing the predetermined time window into a first sub-window and a second sub-window; based on the difference concentration time series data, determining a first mean value within the first sub-window and a second mean value within the second sub-window, respectively; based on the comparison relationship between the first mean value and the second mean value, determining the change trend.

[0035] The preset time window refers to a specific time period for observing and analyzing the difference concentration time series data. The first sub-window and the second sub-window refer to two time periods divided from the preset time window, which can be continuous or discontinuous. The difference concentration time series data refers to a data sequence of the change of the difference between the nitrate concentrations at the inlet and outlet of the anoxic treatment unit over time. The first mean value refers to the average value of the difference concentration time series data in the first sub-window, which can be obtained by summing the data points in the time period and dividing by the number of data points. The second mean value refers to the average value of the difference concentration time series data in the second sub-window, which can be obtained by summing the data points in the time period and dividing by the number of data points. The comparison relationship refers to the size or relative difference relationship between the first mean value and the second mean value. The change trend refers to the overall upward, downward or stable tendency of the difference concentration time series data in the preset time window.

[0036] The scheme of the present application divides the preset time window into a first sub-window and a second sub-window, thereby dividing the observation time period into two parts. Based on the difference concentration time series data, the first mean value in the first sub-window and the second mean value in the second sub-window are calculated. By calculating the mean value, 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 comparison relationship between the first mean value and the second mean value, the change trend is determined. By comparing the average levels of the two time periods, it can be directly judged whether the difference concentration time series data in the preset time window is overall increasing, decreasing or remaining stable. This method provides an objective and quantitative way to evaluate the change of the nitrate removal efficiency of the anoxic treatment unit over time, thereby accurately obtaining the recovery rate index representing the microbial recovery rate. 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.

[0037] As an embodiment of the present application, based on the comparison relationship between the first mean value and the second mean value, the step of determining the change trend comprises: setting a preset trend judgment threshold value; comparing the difference between the second mean value and the first mean value with the preset trend judgment threshold value to obtain a comparison result; determining the change trend according to the comparison result, wherein when the difference between the second mean value and the first mean value is greater than the preset trend judgment threshold value, the change trend is determined to be enhanced; when the difference between the second mean value and the first mean value is less than a negative preset trend judgment threshold value, the change trend is determined to be weakened; otherwise, the change trend is determined to be stable.

[0038] The preset trend judgment threshold refers to a reference value for distinguishing the change range 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 relationship judgment of the difference between the second mean value and the first mean value relative to the preset trend judgment threshold and its negative value, which can be obtained by numerical comparison operation; the change trend refers to the overall change direction and amplitude judgment of the difference concentration time series data within the preset time window, and the enhancement indicates that the nitrate removal efficiency has a significant improvement, the weakening indicates that the nitrate removal efficiency has a significant decrease, and the stability indicates that the nitrate removal efficiency has no significant change.

[0039] The scheme of the present application sets a preset trend judgment threshold through the above steps, which is used to quantitatively judge whether the change range of the difference concentration time series data within the preset time window is significant. Specifically, on the basis of calculating the first mean value and the second mean value, the difference between the second mean value and the first mean value 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 has a significant improvement relative to the former sub-window, so the change trend is determined to be enhanced. If the difference is less than the negative threshold, it indicates that the average removal efficiency has a significant decrease, 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 the random fluctuations commonly seen in wastewater treatment by introducing a threshold, avoids misjudgment of the trend due to minor fluctuations, and makes the evaluation 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 true recovery degree of microbial activity, providing key information for subsequent judgment of whether to meet the exit safety mode condition, and improving the reliability of the entire wastewater treatment regulation correction method.

[0040] As an embodiment of the present application, the step of setting a preset trend judgment threshold comprises: In the transition control phase, the fluctuation degree index of the difference concentration time series data within the preset time window is obtained; Based on the fluctuation degree index, the trend judgment threshold is determined.

[0041] Specifically, the transition control phase refers to an intermediate phase after the safety mode is exited, instead of directly resuming the regular control mode, aiming to smoothly switch the system from the low-load safety mode to the regular control mode according to real-time signal control, avoiding the system instability again due to load mutation. The difference concentration time series data refers to the difference sequence of nitrate concentrations at the inlet and outlet of the anoxic treatment unit over time, which directly reflects the removal capacity or efficiency of the anoxic treatment unit for nitrate at different times. The preset time window refers to a continuous time range used to analyze the change trend or fluctuation degree of the difference concentration time series data, and the length thereof can be set according to the response characteristics and monitoring frequency of the actual system. The fluctuation degree index refers to a value used to quantify the fluctuation degree of the difference concentration time series data within the preset time window, which can be represented by statistical quantities such as standard deviation, variance, range, and mean absolute deviation. The trend judgment threshold refers to a critical value used to judge the change trend (enhancement, weakening, or stability) of the difference concentration time series data within the preset time window, and the judgment is made by comparing the data change with the threshold.

[0042] Through the above method, the scheme of the present application can realize the following working principle: in the transition control phase, the system obtains the fluctuation degree index of the difference concentration time series data within the preset time window, and determines the trend judgment threshold based on the fluctuation degree index. This way no longer uses a fixed threshold, but dynamically adjusts the threshold size according to the actual running fluctuation of the system. When the system fluctuates greatly, the calculated fluctuation degree index will be higher, and the trend judgment threshold determined accordingly will also increase accordingly, which can effectively filter out the influence of normal system fluctuation on trend judgment, and avoid misjudging non-restoration fluctuation as a change in restoration rate. Conversely, when the system runs smoothly and the fluctuation degree index is low, the determined trend judgment threshold will also decrease, making the trend judgment more sensitive to the subtle changes in the microbial restoration rate. Through this way of adaptively adjusting the trend judgment threshold according to the real-time fluctuation, the accuracy of the change trend judgment of the difference concentration time series data is improved. This accurate trend judgment can more reliably reflect the real restoration rate of microorganisms in the anoxic treatment unit, providing a more solid foundation for determining the length of the audit time window based on the restoration rate index, so that the duration of the transition control phase can more accurately adapt to the actual restoration process of microorganisms and external load changes, ultimately realizing the smooth and efficient switching of the system from the safety mode to the regular mode, avoiding the system instability or restoration delay caused by misjudgment.

[0043] As an embodiment of the present application, based on the fluctuation degree index, the step of determining the trend judgment threshold comprises: obtaining the mean value of the difference concentration time series data within the preset time window as the average removal efficiency index; obtaining the adjusted fluctuation sensitivity coefficient; determine a trend judgment threshold based on the adjusted volatility sensitivity coefficient; An adjusted volatility sensitivity coefficient is determined according to the following formula: k_adj = k_max - (k_max - k_min) * f wherein k_adj is the adjusted volatility sensitivity coefficient, k_max is a preset maximum volatility sensitivity coefficient, k_min is a preset minimum volatility 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 indicator to a preset reference efficiency level, and f takes a value of 1 when the ratio is greater than 1, otherwise f takes a value of the ratio; The trend judgment threshold is determined according to the following formula: h = k_adj * S + Th_base wherein Th is the trend judgment threshold, S is the volatility degree indicator, and Th_base is a preset base judgment threshold.

[0044] wherein the average removal efficiency indicator is the mean value of the difference concentration time series data within a preset time window, and its purpose is to quantify the average denitrification effect of the anoxic treatment unit within a period of time; the adjusted volatility sensitivity coefficient k_adj is a coefficient for adjusting the influence of the volatility degree S on the trend judgment threshold Th, and its value is dynamically adjusted according to the average removal efficiency indicator, and its purpose is to make the sensitivity of the threshold to the volatility adapt to different system efficiency levels; the maximum volatility sensitivity coefficient k_max is a preset upper limit value of k_adj, and its purpose is to limit the maximum possible value of k_adj; the minimum volatility sensitivity coefficient k_min is a preset lower limit value of k_adj, and its purpose is to limit the minimum possible value of k_adj; the efficiency level factor f is a factor between 0 and 1, reflecting the level of the current average removal efficiency relative to the reference efficiency level, and its purpose is to map the average removal efficiency to a proportional factor for adjusting the volatility sensitivity coefficient; the reference efficiency level is a preset benchmark value for measuring the level of the current 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 is a threshold for judging the trend of the difference concentration time series data, and its value takes into account the volatility degree and the average removal efficiency, and its purpose is to provide a dynamically adjusted judgment standard; the volatility degree indicator S is the volatility of the difference concentration time series data within a preset time window, which can be represented by standard deviation or range, for example, and its purpose is to quantify the dispersion degree of the data sequence; the base judgment threshold Th_base is a preset constant, and its purpose is to ensure that Th has a minimum benchmark value, avoiding that the threshold is too low when the volatility is extremely small.

[0045] This application's solution dynamically adjusts the trend judgment threshold by introducing an average removal efficiency index and combining it with a fluctuation level index. First, the average removal efficiency over a period of time is calculated, reflecting the system's overall nitrogen removal capacity. Then, an efficiency level factor f is determined based on the ratio of the average removal efficiency to a reference efficiency level. When the average removal efficiency is high, f approaches 1; when the average removal efficiency is low, f approaches the ratio. The fluctuation sensitivity coefficient k_adj is adjusted using f. The formula k_adj = k_max - (k_max - k_min) * f means that when f is larger (higher average efficiency), k_adj is smaller, and the impact of fluctuation on the threshold is weakened; when f is smaller (lower average efficiency), k_adj is larger, and the impact of fluctuation on the threshold is enhanced. Finally, the trend judgment threshold is calculated according to Th = k_adj * S + Th_base. Thus, the threshold depends not only on the current fluctuation level S but also on the current average removal efficiency level reflected by k_adj. This mechanism ensures that when the system recovers well (high average efficiency), the threshold will not be too high even with some fluctuations, avoiding false alarms. Conversely, when the system recovers slowly (low average efficiency), the threshold can more sensitively reflect minute changes and promptly capture signs of recovery, even with small fluctuations. By introducing an average removal efficiency adjustment, the threshold becomes more adaptable to different system states, improving the accuracy of the judgment.

[0046] like Figure 2 The system shown is a food wastewater treatment and control system, which includes: The test pulse dosing module 201 is used to add a preset amount of internal carbon source liquid into the internal reflux path as a test pulse during safe mode operation, based on a fixed low flow rate dosing, at a preset test cycle. The test response rate acquisition module 202 is used to acquire the actual rate of decrease of nitrate concentration in the internal reflux path after the test pulse is applied, as the test response rate. The comparison module 203 is used to compare the trial response rate with the preset recovery baseline rate to obtain the comparison result; The mode switching control module 204 is used to terminate the safety mode and restore the conventional control mode, which controls the addition of internal carbon source liquid based on the real-time detection signal of nitrate concentration in the internal reflux path, when the comparison result meets the preset exit conditions.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for controlling food wastewater treatment, applied to a wastewater treatment system, the wastewater treatment system comprising an anoxic treatment unit for denitrification and an aerobic treatment unit for nitrification, and provided with an internal recirculation path for returning the effluent from the aerobic treatment unit to the anoxic treatment unit, characterized in that, The method includes: During safe mode operation, a preset amount of internal carbon source liquid is added to the internal reflux path at a preset trial cycle, based on a fixed low flow rate, as a trial pulse; After the test pulse is applied, the actual rate of decrease of nitrate concentration in the internal reflux path is obtained as the test response rate. The trial response rate is compared with a preset recovery baseline rate to obtain a comparison result; When the comparison result meets the preset exit condition, the safety mode is terminated and the system is restored to the conventional control mode that controls the addition of internal carbon source liquid based on the real-time detection signal of nitrate concentration in the internal reflux path; a PID controller is used to adjust the carbon source addition flow rate according to the deviation between the nitrate concentration and the target value. The step of terminating the safety mode and reverting to the conventional control mode of controlling the addition of internal carbon source solution based on the real-time detection signal of nitrate concentration in the internal reflux path when the comparison result meets the preset exit condition includes: Initiate a transitional control phase instead of directly reverting to the normal control mode; During the transition control phase, a reference injection rate that increases over time is determined. During the transition control phase, a feedback dosing rate is determined based on the deviation between the real-time nitrate concentration in the internal reflux path and a target value. The dosing rate of the internal carbon source liquid is determined based on the baseline dosing rate and the feedback dosing rate, and according to a control weight that increases over time. After the preset termination condition is met during the transition control phase, the transition control phase is terminated and the system switches to the normal control mode. The step of terminating the transition control phase and switching to the normal control mode after the preset termination condition is met during the transition control phase includes: Acquire upstream load information that characterizes the future production activities of upstream enterprises, including the preset start time of high-load production events; 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 the judgment result; When the judgment result indicates that the high-load production event does not fall within the review time window, the transition control phase is terminated and the system switches to the normal control mode. When the judgment result indicates that the high-load production event falls within the review time window, the operation of the transition control phase is maintained.

2. The method for treating and regulating food wastewater according to claim 1, 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 characterizing the microbial recovery rate within the hypoxia treatment unit is acquired. Based on the recovery rate metric, the duration of the review time window is determined; Based on the current time, the preset start time of the high-load production event, and the duration of the determined review time window, it is determined whether the high-load production event falls within the review time window.

3. The method for regulating and controlling food wastewater treatment according to claim 2, characterized in that, The step of obtaining the recovery rate index characterizing the microbial recovery rate within the hypoxia treatment unit includes: The nitrate concentrations at the inlet and outlet of the hypoxia treatment unit are obtained to form inlet concentration time series data and outlet concentration time series data; Based on the inlet concentration time series data and the outlet concentration time series data, the difference concentration time series data characterizing the nitrate removal efficiency of the anoxic treatment unit is determined. The trend of the difference concentration time series data within a preset time window is determined, and the trend is used as the recovery rate indicator.

4. The method for regulating and controlling food wastewater treatment according to claim 3, characterized in that, The step of determining the changing trend of the time series data of the difference concentration within a preset time window includes: The preset time window is divided into a first sub-window and a second sub-window; Based on the time series data of the difference concentration, the first mean value in the first sub-window and the second mean value in the second sub-window are determined respectively; The trend of change is determined based on the comparison between the first mean and the second mean.

5. The method for regulating and controlling food wastewater treatment according to claim 4, characterized in that, The step of determining the trend of change based on the comparison between the first mean and the second mean includes: Set a preset trend judgment threshold; The difference between the second mean and the first mean is compared with the preset trend judgment threshold to obtain the comparison result; Based on the comparison results, the trend of change is determined, wherein when the difference between the second mean and the first mean is greater than the preset trend judgment threshold, the trend of change is determined to be strengthening; when the difference between the second mean and the first mean is less than a negative preset trend judgment threshold, the trend of change is determined to be weakening; otherwise, the trend of change is determined to be stable.

6. The method for regulating and controlling food wastewater treatment according to claim 5, characterized in that, The step of setting a preset trend judgment threshold includes: During the transition control phase, the fluctuation index of the time series data of the difference concentration within a preset time window is obtained; Based on the volatility index, the trend judgment threshold is determined.

7. The method for treating and regulating food wastewater according to claim 6, characterized in that, The step of determining the trend judgment threshold based on the volatility index includes: The mean value of the time series data of the difference concentration within the preset time window is obtained as the average removal efficiency index. Obtain the adjusted volatility sensitivity coefficient; The trend judgment threshold is determined based on the adjusted fluctuation sensitivity coefficient.

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