A tidal flow control method and device for constructed wetland based on siphon principle

Abstract

The application provides a tidal flow control method and device for constructed wetlands based on the siphon principle, aiming to realize periodic rise and fall of the water level of the wetland by constructing an automatic siphon drainage device, and to create a dry-wet alternating environment similar to biological respiration; a plant root secretion concentration monitoring technology is used to convert the physiological signals of plants into adjustment parameters of the siphon trigger point, so as to realize biological feedback control; a dual-mode operation mechanism of rapid drainage and slow infiltration is designed, and a mode switching strategy is determined by constructing a complementary analysis matrix; vertical activity areas are divided based on the oxygen utilization characteristics of microorganisms, and a gradient filler-plant combination is configured accordingly; an endogenous carbon release regulation method is developed for seasonal temperature changes, and the directional release of organic matter is promoted by optimizing the dry-wet rhythm; and finally, an adaptive control method based on the multi-parameter feedback of water quality-biology-temperature is formed, so that the stable and efficient operation of the constructed wetland under different load and temperature conditions can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of artificial wetland water treatment, in particular to a tidal flow control method and device for artificial wetland based on siphon principle. BACKGROUND

[0002] As an ecological-friendly wastewater treatment technology, artificial wetland plays an important role in nitrogen removal. However, traditional artificial wetlands usually adopt simple operation modes of continuous flow or intermittent flow, which have problems such as uneven distribution of dissolved oxygen, low efficiency of nitrification and denitrification, unstable treatment effect, etc., and are difficult to adapt to dynamic changes of influent water quality and seasonal temperature, resulting in large fluctuations of effluent water quality and lack of intelligent control ability of system operation.

[0003] Existing artificial wetland control technology mainly relies on manual experience or simple time sequence control, and cannot realize adaptive adjustment based on biological feedback, and lacks real-time response mechanism to plant physiological state and microbial metabolic characteristics. Especially under different temperature conditions, the problem of carbon source supply required for denitrification process has always been a key bottleneck restricting the denitrification efficiency of wetland, and an intelligent control method capable of automatically adjusting operation parameters according to system state and realizing stable operation in full temperature range is urgently needed. SUMMARY

[0004] The present application provides a tidal flow control method and device for artificial wetland based on siphon principle, aiming to solve the technical problems of uneven distribution of dissolved oxygen, low treatment efficiency and lack of intelligent control in traditional artificial wetland, realize automatic water level control through siphon principle, dynamically optimize operation parameters combined with biological feedback mechanism, and develop differentiated carbon source supply strategies for different temperature conditions, finally realize intelligent and efficient operation of artificial wetland, and provide a new ecological treatment technology scheme for the field of wastewater treatment.

[0005] The present application provides a tidal flow control method and device for artificial wetland based on siphon principle, aiming to solve the technical problems of uneven distribution of dissolved oxygen, low treatment efficiency and lack of intelligent control in traditional artificial wetland, realize automatic water level control through siphon principle, dynamically optimize operation parameters combined with biological feedback mechanism, and develop differentiated carbon source supply strategies for different temperature conditions, finally realize intelligent and efficient operation of artificial wetland, and provide a new ecological treatment technology scheme for the field of wastewater treatment.

[0006] Selecting suitable siphon device material generating components based on the component list to obtain siphon device layout;

[0007] Conducting continuous drainage test on the siphon device layout to obtain continuous drainage rule, conducting intermittent drainage test on the siphon device layout to obtain intermittent drainage rule, comparing the difference between the continuous drainage rule and the intermittent drainage rule to determine optimal wetland emptying speed, and setting influent control frequency according to the optimal wetland emptying speed;

[0008] Based on the influent control frequency, water quality monitoring is performed to obtain influent ammonia nitrogen concentration data, the dry-wet ratio is dynamically adjusted based on the ammonia nitrogen concentration data to generate dry-wet ratio parameter, and a dissolved oxygen control scheme is developed based on the dry-wet ratio parameter.

[0009] Performing microbial community metabolic response analysis on the dissolved oxygen control scheme to obtain oxygen utilization conditions, determining the distribution of microbial activity regions based on the oxygen utilization conditions, planning vertical layered biological reaction zones based on the distribution of the activity regions to generate a nitrification-denitrification partitioning strategy, and configuring the filler and plant combination according to the nitrification-denitrification partitioning strategy;

[0010] Setting a water quality sensing type siphon trigger point based on the filler and plant combination, monitoring the concentration change of plant root exudates according to the water quality sensing type siphon trigger point, and adaptively adjusting the water quality sensing type siphon trigger point to obtain a biological feedback adjustment parameter based on the concentration change of the root exudates;

[0011] Simultaneously constructing a rapid drainage mode and a slow infiltration mode based on the biological feedback adjustment parameter, performing contradictory synergy analysis on the rapid drainage mode and the slow infiltration mode to generate an intelligent tidal change mode, and determining a dry-wet alternating frequency based on the intelligent tidal change mode;

[0012] Performing water temperature analysis on the dry-wet alternating frequency to obtain a temperature change trend, constructing a water temperature responsive endogenous carbon release method based on the temperature change trend, generating a full-temperature-range denitrification guarantee strategy based on the carbon release method, and completing adaptive control of the artificial wetland tidal flow.

[0013] The second aspect of the present application proposes an artificial wetland tidal flow control device based on the siphon principle, comprising:

[0014] A device construction module for selecting suitable siphon device materials to generate a component list, and obtaining a siphon device layout based on the component list;

[0015] A drainage test module for performing continuous drainage test on the siphon device layout to obtain a continuous drainage rule, performing intermittent drainage test on the siphon device layout to obtain an intermittent drainage rule, comparing the differences between the continuous drainage rule and the intermittent drainage rule to determine an optimal wetland emptying speed, and setting an inflow control frequency according to the optimal wetland emptying speed;

[0016] A water quality regulation module for performing water quality monitoring based on the inflow control frequency to obtain inflow ammonia nitrogen concentration data, dynamically adjusting the dry-wet ratio based on the ammonia nitrogen concentration data to generate a dry-wet ratio parameter, and formulating a dissolved oxygen control scheme based on the dry-wet ratio parameter;

[0017] A partition optimization module for performing microbial community metabolic response analysis on the dissolved oxygen control scheme to obtain oxygen utilization conditions, determining the distribution of microbial activity regions based on the oxygen utilization conditions, planning vertical layered biological reaction zones based on the distribution of the activity regions to generate a nitrification-denitrification partitioning strategy, and configuring the filler and plant combination according to the nitrification-denitrification partitioning strategy;

[0018] a feedback adjustment module configured to set a water quality sensing siphon trigger point based on the filler and the plant combination, monitor a change in root exudate concentration of the plant root system according to the water quality sensing siphon trigger point, and obtain a biological feedback adjustment parameter by adaptively adjusting the water quality sensing siphon trigger point based on the change in root exudate concentration;

[0019] a mode coordination module configured to simultaneously construct a rapid drainage mode and a slow infiltration mode based on the biological feedback adjustment parameter, perform contradictory coordination analysis on the rapid drainage mode and the slow infiltration mode to generate an intelligent tidal change mode, and determine a dry-wet alternating frequency based on the intelligent tidal change mode;

[0020] a temperature guarantee module configured to perform water temperature analysis on the dry-wet alternating frequency to obtain a temperature change trend, construct a water temperature responsive endogenous carbon release method based on the temperature change trend, generate a full-temperature-range denitrification guarantee strategy based on the carbon release method, and complete adaptive control of the artificial wetland tidal flow.

[0021] The beneficial effects of the present application are embodied in the following aspects: first, an artificial wetland operation system simulating biological respiratory rhythm is constructed, periodic "inhaling" (water filling) and "exhaling" (water drainage) of the wetland are realized through the siphon principle, an air-water exchange process similar to lung respiration is formed, the wetland is transformed from a static treatment facility to a dynamic "living system", the "respiration" frequency and depth are automatically adjusted according to the pollution load, and natural coupling between the treatment process and biological metabolic demand is realized. Second, plant root exudates are used as a biological signal source for system control, the plant physiological state is judged by real-time monitoring of the change in exudate concentration, and the siphon trigger water level is automatically adjusted accordingly, a direct dialogue mechanism between "plant language" and hydraulic control is established, the system has intelligent response to plant demand, and truly realizes autonomous regulation and control within the ecological system. Third, a dual-mode contradictory coordination operation mechanism of rapid drainage and slow infiltration is proposed, complementary analysis matrix is constructed to identify the advantage conditions of the two modes, and the operation mode is intelligently switched according to real-time water quality and biological signals, so that the system can cope with sudden high load impact and maintain long-term stable operation, and dynamic balance between treatment efficiency and operation stability is realized.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings herein show specific examples of the technical solutions described in the present application, and constitute part of the specification together with the specific embodiments, for explaining the technical solutions, principles and effects of the present application.

[0024] Unless specifically stated or otherwise as can be apparent from the preceding discussion, it is appreciated that throughout the description, discussion, explanation, and the like, the teachings and descriptions provided throughout this disclosure will be understood to apply to both the method and process steps described therein, as well as the structural elements of the systems, apparatuses, and devices described herein.

[0025] Figure 1 is a flowchart of a tidal flow control method of a constructed wetland based on the siphon principle.

[0026] Figure 2 is a schematic diagram of the overall structure of a constructed wetland tidal flow control system based on the siphon principle.

[0027] Figure 3 is a schematic diagram of the vertical cross-sectional structure of a constructed wetland along the water flow direction.

[0028] Figure 4 is a schematic diagram of the structure of a siphon device and monitoring assembly in a constructed wetland.

[0029] Figure 5 is a structural block diagram of a constructed wetland tidal flow control device based on the siphon principle.

[0030] Legend of reference signs: 1. main water inlet pipe; 2. water inlet control valve; 3. water flow regulating valve; 1A. right water outlet system; 2A. right water outlet control valve; 3A. right water flow regulating valve; 1B. left water inlet system; 2B. left water inlet control valve; 3B. left water flow regulating valve; 4. branch pipe system; 5. wetland filler area; 5A. water distribution layer; 6. water seepage pipe; 7. water collection well; 8. main siphon; 9. auxiliary siphon; 10. communication pipe; 11. water level control point system; 11-1. high water level (H WL); 11-2. high trigger water level (HTL); 11-3. middle stable water level (MSL); 11-4. low cut-off water level (LCL); 12. water collection system; 13. siphon trigger point; 14. siphon elbow; 15. gas-liquid separator; 16. automatic exhaust valve; 17. pressure guide pipe; 18. anti-explosion air hole; 19. check valve; 20. flow control valve; 21. anti-blocking water collection cage; 22. filter screen; 23. horizontal adjusting device; 24. flange; 25. sealing ring; 26. quick connector; 27. fixing support; 28. pressure sensor; 29. electric conductivity sensor; 30. ORP sensor. DETAILED DESCRIPTION

[0031] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular architectures, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application.

[0032] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0033] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0034] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0035] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0037] The technical solutions of the embodiments of this application will be described below.

[0038] like Figure 1 As shown, this embodiment of the invention provides a method for controlling tidal flow in artificial wetlands based on the siphon principle, including the following steps S110-S170:

[0039] Step S110: Select suitable materials for the siphon device to generate a component list, and obtain the layout of the siphon device based on the component list.

[0040] Specifically, suitable materials for the siphon device are selected and a component list is generated. For the automatic control of tidal flow in constructed wetlands, suitable materials for the siphon device are selected by comprehensively considering factors such as corrosion resistance, service life, and economy. For example... Figure 2 As shown, the main inlet pipe (1) is connected to the inlet control valve (2). The inlet control valve (2) distributes the water flow to the branch pipe system (4) through the water flow regulating valve (3). The branch pipe system (4) is arranged in a zigzag pattern, and the water flow is evenly distributed to the wetland filler area (5). The treated water flow is collected in the collection well (7) through the bottom seepage pipe (6), and then discharged by the main siphon (8). The auxiliary siphon (9) is linked with the main system through the connecting pipe (10) to jointly realize the automatic drainage function of the wetland. Figure 3 As shown, the left-side water inlet system (1B) introduces water into the wetland and controls the inlet rate through the left-side water inlet control valve (2B) and the left-side water flow regulating valve (3B). After passing through the wetland, the water flows out through the right-side water outlet system (1A), the right-side water outlet control valve (2A), and the right-side water flow regulating valve (3A). The wetland is vertically arranged with a water distribution layer (5A) and a wetland filling area (5). The water distribution layer (5A) is a special material filling area at the top, using materials with better hydraulic conductivity and dispersion to ensure uniform water flow distribution. The water level control system (11) is arranged from top to bottom as follows: high water level line (11-1), high trigger water level (11-2), intermediate stable water level (11-3), and low cut-off water level (11-4). The water collection system (12) is connected to the siphon trigger point (13) to form a complete automatic water level control system. The main pipelines are made of high-density polyethylene (HDPE); Figure 4 As shown, the siphon bend (14) is connected to the gas-liquid separator (15). An automatic exhaust valve (16) is installed on the top of the gas-liquid separator (15), and a pressure guide pipe (17) is connected to the side. The pressure guide pipe (17) is connected in parallel with the explosion-proof vent (18) to increase safety. A check valve (19) is provided at the outlet of the siphon bend (14) to prevent backflow. A flow control valve (20) precisely adjusts the water flow rate. The inlet of the siphon bend (14) is connected in sequence to the anti-clogging water collection cage (21), the filter screen (22), and the level adjustment device (23). All connection parts are connected by flanges (24). A sealing ring (25) is installed between the flanges to ensure sealing. Quick connectors (26) are set at key nodes for easy maintenance. The entire system is supported and stabilized by a fixed bracket (27). Pressure sensors (28), conductivity sensors (29), and ORP sensors (30) are installed at key positions to monitor the system operation status and water quality changes in real time.

[0041] In some embodiments, obtaining the siphon device layout based on the component list includes: determining siphon start-up conditions based on the component list; establishing water level control parameters based on the siphon start-up conditions; and designing inlet and outlet drainage paths based on the water level control parameters to obtain the siphon device layout.

[0042] According to the siphon device component list, the siphon principle simulation test is carried out to determine the key starting conditions. When the wetland water level rises to the high trigger water level (11-2 / HTL), the siphon trigger point (13) is activated, a 15-20 cm water head difference is formed between the water level and the top of the siphon pipe, the water flow starts to pass through the siphon bend (14), the automatic air vent valve (16) discharges gas, the gas discharge rate exceeds 0.5 L / s, the air in the siphon bend (14) is discharged to form negative pressure, and the siphon phenomenon starts to be stably established, and the water flow is discharged through the check valve (19) and the flow control valve (20). Different specifications of siphon pipes correspond to different starting conditions: for a siphon pipe with a diameter of 50 mm, the starting flow rate needs to reach 0.3-0.4 m / s; for a siphon pipe with a diameter of 80 mm, the starting flow rate is 0.25-0.35 m / s; for a siphon pipe with a diameter of 100 mm, the starting flow rate decreases to 0.2-0.3 m / s. The pressure sensor (28), the conductivity sensor (29) and the ORP sensor (30) respectively monitor the changes of water pressure, water quality and oxidation-reduction potential, when the pressure sensor (28) monitors that the negative pressure in the pipe reaches-5 kPa to-8 kPa, the siphon effect is most stable, at this time the gas-liquid separator (15) effectively separates the gas in the water flow. The minimum water level difference required for stable operation of the siphon device is 1.5-2 times the pipe diameter, for example, a 100 mm pipe diameter requires a minimum water level difference of 150-200 mm.

[0043] Based on the siphon starting conditions, the water level control parameters are established: according to the 15-20 cm water head difference required for siphon starting and the minimum water level difference requirement of 1.5-2 times the pipe diameter, the highest water level line (11-1 / HWL) in the wetland is set to be 10-15 cm below the ground surface, the lowest water level line (11-4 / LWL) is set to be 50-55 cm below the ground surface, forming a 40-45 cm effective water level change interval, which fully meets the 150-200 mm minimum water level difference requirement of the 100 mm pipe diameter siphon device and provides additional operating margin. Between the HWL and the LWL, the high trigger water level (11-2 / HTL) is located 5 cm below the HWL, which ensures that the 15-20 cm water head difference required for siphon starting is met, serving as the trigger point for the siphon device to start; the middle stable water level (11-3 / MSL) is located at the middle position of the HWL and the LWL, which is used to adjust the siphon flow rate change; the low cut-off water level (LCL) is located 5 cm above the LWL, when the water level drops to this position, the anti-explosion air hole (18) introduces air, and the siphon effect is automatically terminated.

[0044] Based on the determined water level control parameters, the spatial layout of the siphon device in the wetland and the water inlet and outlet path are designed. When designing the wetland, the effective change interval of 40-45 cm formed by the HWL and the LWL is considered, and the intermediate diversion structure is set according to the MSL. For a standard rectangular wetland, the water inlet system is divided into multiple branch pipes (4) by the main water inlet pipe (1), the branch pipes are spaced 1.5 m apart, forming a uniform water distribution network, the water flow passes through the wetland filler area (5) for treatment, is collected by multiple seepage pipes (6) with a spacing of 2 m, and is then discharged by the main siphon (8). For irregularly shaped wetlands, the main siphon (8) is arranged at the lowest point, and the auxiliary siphon (9) is distributed in each functional area, and the hydraulic linkage is maintained through the communication pipe (10). The water inlet control valve (2) and the water flow regulating valve (3) work together to adjust the water inlet rate and distribution, the siphon elbow (14) at the water outlet end is connected to the gas-liquid separator (15) and the automatic air vent valve (16), which ensures the stable operation of the siphon effect. The siphon trigger point (13) corresponds to the high trigger water level (11-2 / HTL), when the water level rises to this height, the air is discharged through the automatic air vent valve (16) to start the siphon effect; when the water level drops to the low cut-off water level (LCL), the explosion-proof air hole (18) introduces air to interrupt the siphon effect. The pressure guide pipe (17) connects the gas-liquid separator (15) with the monitoring system to monitor the system operation state in real time. The water inlet assembly includes a anti-blocking water collection cage (21) to prevent large particles from entering, a filter screen (22) for further filtration, and a horizontal adjustment device (23) for controlling the level, and the three components are sequentially connected to ensure the water inlet quality. The entire system is sealed and connected through flanges (24) and sealing rings (25), quick connectors (26) are used at key nodes for easy maintenance, and all components are firmly supported by fixed supports (27). According to the "water level-time" control curve, the water flow distribution is optimized to be synchronized with the water level change, and finally a detailed siphon device layout scheme is formed.

[0045] In step S120, continuous drainage testing is performed on the siphon device layout to obtain the continuous drainage rule, intermittent drainage testing is performed on the siphon device layout to obtain the intermittent drainage rule, the differences between the continuous drainage rule and the intermittent drainage rule are compared to determine the optimal wetland emptying speed, and the water inlet control frequency is set according to the optimal wetland emptying speed.

[0046] Specifically, based on the siphon device layout scheme, the installed siphon system was tested in continuous drainage mode. The wetland water level was raised to the high trigger water level (11-2) at the start of the test, ensuring that the main siphon (8) and the auxiliary siphon (9) reached the starting condition at the same time. During the continuous drainage process, after the siphon trigger point (13) was activated, the automatic exhaust valve (16) continuously discharged air in the pipe, a stable negative pressure was formed in the siphon elbow (14), and the pressure sensor (28) monitored and displayed that the negative pressure value maintained in the range of-5 to-8 kPa. The water flow was continuously discharged through the main siphon (8), and the flow control valve (20) remained in the fully open state to ensure maximum drainage capacity. Process monitoring used multi-parameter synchronous recording, including instantaneous flow, cumulative drainage volume, water level drop rate, and pipe pressure change. The drainage rate curve showed three-stage characteristics: the initial stage was affected by the siphon establishment process, the flow increased rapidly; the stable stage maintained a constant flow, determined by the pipe diameter and water head difference; and the final stage gradually decreased as the water level decreased. The conductivity sensor (29) and ORP sensor (30) monitored the water quality changes simultaneously, and it was found that the conductivity gradually increased during the continuous drainage process, indicating that the high-concentration sewage at the bottom was preferentially discharged. The drainage ended at the low cut-off water level (11-4), and the explosion-proof air hole (18) introduced air to destroy the siphon. Through the duration record of the complete continuous drainage cycle and the analysis of the multi-parameter monitoring data, the continuous drainage law was obtained.

[0047] Under the same siphon device layout conditions, intermittent drainage mode test was conducted to compare the effects of different operation modes. The intermittent mode was realized through the coordinated control of the water inlet control valve (2) and the flow control valve (20), and the cycle period of drainage-stop was set. The water level was also raised to the high trigger water level (11-2) at the start of the test, and the siphon was started and then the flow control valve (20) was closed automatically after a preset time, interrupting the siphon action. During the stop period, the water in the wetland substrate slowly infiltrated under the action of gravity and capillary force, the residual water in the gas-liquid separator (15) was discharged, and the pipeline system returned to the initial state. The intermittent cycle was set considering various time combinations: short cycle mode for 15 minutes of drainage and 30 minutes of stop; medium cycle mode for 30 minutes of drainage and 60 minutes of stop; and long cycle mode for 60 minutes of drainage and 120 minutes of stop. The drainage characteristics in each cycle were similar to those in the continuous mode, but the frequent start-stop resulted in an increase in the siphon establishment time. The advantage of intermittent mode is that the stop period provides a time window for wetland reoxygenation, and the pressure sensor (28) data shows that the pressure in the pipe returns to normal during the stop period, which is beneficial to air entry. Water quality monitoring found that the water quality fluctuated greatly during intermittent drainage, and the water quality was poor at the beginning of each cycle and gradually improved later. The horizontal adjustment device (23) played a more important role in the intermittent mode, ensuring consistent water inlet conditions for each restart. Through statistical analysis and feature extraction of the test data of multiple cycles, the intermittent drainage law was obtained.

[0048] In some embodiments, the determining the optimal wetland emptying speed based on the difference between the continuous drainage pattern and the intermittent drainage pattern comprises: comparing the continuous drainage pattern and the intermittent drainage pattern to identify a drainage rate change feature; analyzing a wetland reoxygenation process based on the drainage rate change feature to obtain reoxygenation efficiency data; determining a suitable emptying time according to the reoxygenation efficiency data; and determining the optimal wetland emptying speed based on the emptying time.

[0049] The test data of continuous drainage and intermittent drainage are compared and analyzed, and the dynamic change features of the drainage rate under the two modes are identified. The drainage rate curve of the continuous mode presents a smooth single-peak feature, the peak value appears after the establishment of the stable siphon, and then slowly decreases until termination; the intermittent mode presents a multi-peak jagged shape, and each cycle experiences rapid rise and sharp decline. The quantitative analysis of the rate change uses the differential method to calculate the instantaneous acceleration dQ / dt. The acceleration change of the continuous mode is gentle, and the acceleration of the intermittent mode appears extreme value at the start-stop moment. The comparison of the cumulative drainage volume shows that the total drainage volume of the continuous mode is greater than that of the intermittent mode in the same time, but the average drainage rate of the latter is higher during the drainage period. The comparison of the water level drop curve reveals different emptying modes. The continuous drainage presents exponential decay, and the intermittent drainage presents stepwise decline. The frequency spectrum analysis of the drainage rate finds that the continuous mode is dominated by low-frequency components, and the intermittent mode contains rich high-frequency components, reflecting the influence of periodic start-stop. The influence of the rate change on the internal flow pattern of the wetland is verified by the tracer test. The continuous mode forms a stable preferential flow path, and the flow path of the intermittent mode is adjusted in each cycle. Through the systematic comparison and difference identification of the drainage characteristics of the two modes, the drainage rate change feature is finally obtained.

[0050] For example, the analyzing a wetland reoxygenation process based on the drainage rate change feature to obtain reoxygenation efficiency data comprises: identifying a rapid drainage stage and a slow drainage stage according to the drainage rate change feature; determining the rate of air entering the wetland substrate based on the rapid drainage stage to obtain initial reoxygenation intensity; monitoring the diffusion depth of oxygen in the substrate based on the slow drainage stage to obtain deep reoxygenation degree; and generating reoxygenation efficiency data by integrating the initial reoxygenation intensity and the deep reoxygenation degree.

[0051] Firstly, the drainage process was divided into fast drainage stage and slow drainage stage according to the slope change of the drainage rate curve. The fast drainage stage corresponds to the period when the siphon effect is fully developed, and the drainage rate is greater than 1.5 times the average value. It mainly occurs when the water level drops from the high trigger water level (11-2) to the intermediate stable water level (11-3). The slow drainage stage occurs near the low cut-off water level (11-4), when the siphon driving force weakens and the drainage rate drops to less than 0.5 times the average value. The transition point between the two stages is determined by the second derivative of the drainage rate, which changes from negative to positive, indicating the start of the slow stage. The fast stage accounts for 30-40% of the total drainage time, but completes 60-70% of the drainage volume. The slow stage takes a long time and mainly serves to slowly dewater the deep layers of the substrate. Then, in the fast drainage stage, the dynamic characteristics of air entering the substrate during the rapid downward movement of the air-water interface are monitored. The air entry rate is determined by measuring the oxygen concentration at different depths when it suddenly changes from near zero to more than 2 mg / L. The air front is marked when the oxygen concentration at a certain depth increases to more than 2 mg / L. The negative pressure effect of fast drainage accelerates the intake of air. According to the Bernoulli equation, the negative pressure generated by high-speed water flow in the pores can reach -2 to -3 kPa, significantly enhancing the permeability of air. The quantitative indicator of initial reoxygenation intensity is represented by the oxygen transfer per unit volume per unit time. The reoxygenation intensity in the fast stage is I_fast = ΔO2 / (V×Δt), where ΔO2 is the oxygen increment, V is the substrate volume, and Δt is the time interval. Reoxygenation in the fast drainage stage mainly occurs in large pores and around water flow channels, forming an uneven oxygen distribution pattern. The turbulent effect is more pronounced during fast drainage, enhancing the mixing of gas and liquid phases. Through the analysis of reoxygenation kinetics and quantitative monitoring in the fast stage, the initial reoxygenation intensity is obtained. Then, the reoxygenation process in the slow drainage stage is dominated by diffusion mechanisms, and the monitoring focus shifts to the penetration depth and distribution uniformity of oxygen in the deep layers of the substrate. Oxygen diffusion follows Fick's law, with the diffusion flux being proportional to the concentration gradient. Since the water flow velocity is low in the slow stage, convective mass transfer is weakened, and molecular diffusion becomes the main mass transfer method. The deep reoxygenation level is evaluated by a multi-point dissolved oxygen monitoring network, with a monitoring point set every 10 cm in the vertical direction to record the oxygen concentration-time curve. The diffusion depth is defined as the maximum depth at which the oxygen concentration reaches 0.5 mg / L, which is considered the minimum requirement for microbial activity. After continuous and stable deep reoxygenation process monitoring and evaluation, the deep reoxygenation level is obtained. Finally, the initial reoxygenation intensity and deep reoxygenation level are analyzed comprehensively to establish a comprehensive evaluation system for reoxygenation efficiency. The calculation formula for reoxygenation efficiency η is η = α×I_fast×t_fast + β×D_slow×U_slow, where I_fast is the initial reoxygenation intensity, t_fast is the duration of the fast stage, D_slow is the deep reoxygenation depth, U_slow is the reoxygenation uniformity index, and α and β are weight coefficients.The determination of the weight coefficient considers the main functional requirements of the wetland. For a system dominated by nitrification, initial reoxygenation is more important, and a is taken as 0.6. For a system requiring deep denitrification, deep reoxygenation is more critical, and b is taken as 0.6. The reoxygenation efficiency also needs to consider the energy consumption factor. Although rapid drainage has high initial reoxygenation intensity, it requires a larger water head difference and relatively high energy consumption. Time efficiency analysis shows that although the intermittent mode has a longer total time, the effective reoxygenation time utilization rate is higher. Finally, the reoxygenation efficiency data is generated by calculating and evaluating the reoxygenation efficiency of multiple dimensions.

[0052] According to the optimal reoxygenation mode revealed in the reoxygenation efficiency data, the appropriate emptying time is determined to meet the full reoxygenation and ensure the treatment efficiency. The determination of the optimal emptying time needs to balance multiple goals: sufficient reoxygenation time to ensure the activity of aerobic microorganisms, moderate wet period to maintain the survival of anaerobic microorganisms, and reasonable cycle length to ensure daily treatment capacity. The reoxygenation efficiency curve shows that when the emptying time is in the interval of 4-6 hours, the reoxygenation efficiency reaches the peak platform, and the marginal contribution of further extending the emptying time to reoxygenation is small. Microbial activity monitoring shows that when the emptying time is less than 3 hours, the activity of nitrifying bacteria does not recover fully, and the nitrification efficiency is less than 70% of the design value; when the emptying time exceeds 8 hours, part of the anaerobic bacteria is inactivated due to excessive drying. Water balance analysis determines the critical emptying time to maintain the appropriate humidity of the substrate, preventing substrate cracking and preferential flow formation caused by excessive drying. The treatment capacity constraint requires that the daily treatment water quantity should not be less than the design scale, limiting the upper limit of the single emptying time. The consideration of seasonal factors is realized by setting two sets of emptying time parameters for summer and winter. In summer, the evaporation amount is large, and the emptying time is shortened accordingly; in winter, the microbial activity is low, and the reoxygenation time needs to be extended. Based on the comprehensive multi-objective optimization and constraint condition analysis, the appropriate emptying time is determined.

[0053] Based on the determined suitable emptying time, the optimal wetland emptying speed is determined through hydraulic calculation. The basic calculation formula of emptying speed is v = H / T, where H is the effective water level change height, that is, the vertical distance from the high trigger water level (11-2) to the low cut-off water level (11-4); T is the suitable emptying time. According to the water level control parameters determined in S110, the effective water level change height is clear; the suitable emptying time is determined by optimizing the reoxygenation efficiency, and a balance needs to be struck between sufficient reoxygenation and treatment efficiency. The actual emptying speed also needs to consider the physical limitations of the siphon system, the pipe diameter of the main siphon (8) determines the maximum flow rate, and too high an emptying speed will exceed the pipe conveying capacity; too low an emptying speed cannot maintain stable siphon action, and is easy to accumulate bubbles in the siphon elbow (14). The adjustment range of the flow control valve (20) provides a controllable interval for the emptying speed, and by changing the valve opening, the actual emptying speed can be adjusted within a certain range. The substrate characteristics also constrain the emptying speed, too fast emptying will cause water flow scouring and carry away fine particles in the substrate; moderate speed can ensure uniform water infiltration and maintain stable substrate structure. Temperature factors indirectly affect the emptying speed by affecting the physical properties of water, the viscosity of water increases at low temperature in winter, and the emptying speed will decrease under the same driving force; the summer is the opposite. By comprehensively considering the water level height, time requirement, system capacity and environmental factors, the optimal wetland emptying speed is determined.

[0054] According to the optimal wetland emptying speed, a reasonable water inflow control frequency is set to realize the automatic control of tidal flow. The water inflow control frequency f = 1 / (T_fill + T_drain + T_rest), where T_fill is the water filling time, T_drain is the water draining time based on the optimal speed, and T_rest is the static reaction time. The determination of the water filling time considers the water inflow and the target water level, and realizes fast water filling through the cooperation control of the main water inflow pipe (1) and the water inflow control valve (2), and the typical water filling time is 1-2 hours. The water draining time is calculated according to the optimal emptying speed, to ensure sufficient reoxygenation effect. The static time provides a stable environment for microbial reaction, and is dynamically adjusted according to the water quality monitoring results, and the static time is appropriately prolonged when the ammonia nitrogen concentration is high. The control system uses a time sequence controller to automatically switch the water filling, static and water draining stages according to the set frequency. The fine adjustment of the frequency is realized through online monitoring of water quality, and the data of the conductivity sensor (29) and the ORP sensor (30) are used to evaluate the treatment effect, and the frequency is automatically reduced and the reaction time is prolonged when the effect is poor. The guarantee of daily treatment capacity is realized through the setting of the lower limit of the frequency, to ensure that the number of daily cycles is not less than the design requirement. The seasonal adjustment strategy adjusts the frequency according to the temperature and water inflow water quality changes, and the frequency is appropriately reduced in winter and increased in summer. Based on the multi-parameter collaborative optimization and automatic control strategy, the setting of the water inflow control frequency is finally completed.

[0055] At step S130, water quality monitoring is performed based on the water inflow control frequency to obtain ammonia-nitrogen concentration data of the water inflow, the dry-wet ratio parameter is dynamically adjusted based on the ammonia-nitrogen concentration data, and a dissolved oxygen control scheme is formulated based on the dry-wet ratio parameter.

[0056] Specifically, according to the water inflow control frequency, water quality monitoring is performed at key time nodes in each water inflow cycle, focusing on the dynamic changes of ammonia-nitrogen concentration. The monitoring point is set at the main water inflow pipe (1), and an online ammonia-nitrogen analyzer is used for continuous monitoring with a sampling interval synchronized with the water inflow control frequency. Each water inflow cycle includes three stages of water filling, standing, and water draining. An initial sample of the water inflow is collected at the beginning of water filling to record the ammonia-nitrogen concentration of the raw water; a sample is collected again at the end of water filling to evaluate the concentration change during water filling; a sample is collected in the middle of the standing stage to monitor the ammonia-nitrogen conversion inside the wetland; and a sample of the effluent is collected in the water draining stage to calculate the ammonia-nitrogen removal efficiency. The monitoring data is automatically recorded by the data acquisition system to form a time series database. The daily variation of ammonia-nitrogen concentration shows obvious characteristics. In the morning, the ammonia-nitrogen concentration reaches a daily peak due to the concentrated discharge of domestic sewage; in the afternoon, the concentration decreases due to dilution; and at night, the concentration may increase again due to the discharge of industrial wastewater. The weekly variation is related to the rhythm of production and life, with higher concentration on weekdays than on weekends. Seasonal variation is mainly affected by temperature and rainfall. In summer, high temperature promotes ammonification, resulting in relatively high concentration; in the rainy season, dilution reduces the concentration. Through multi-time scale water quality monitoring and data accumulation, ammonia-nitrogen concentration data of the water inflow are obtained.

[0057] Based on real-time and historical ammonia nitrogen concentration data, a concentration and dry-wet ratio response relationship is established. The dry-wet ratio is defined as the ratio of dry time to wet time in a complete cycle, which directly affects the nitrification and denitrification efficiency of the wetland. Under high ammonia nitrogen concentration conditions, it is necessary to extend the wet time to provide sufficient nitrification reaction time, while appropriately shortening the dry time to prevent ammonia nitrogen accumulation; under low ammonia nitrogen concentration conditions, the wet time can be shortened and the dry time can be extended to strengthen the reoxygenation effect. The adjustment of the dry-wet ratio is realized by changing the timing of the influent control valve (2) and the flow control valve (20), and under the premise of keeping the total cycle time unchanged, the wet and dry periods are flexibly allocated. The adjustment strategy adopts segmented control, divides the ammonia nitrogen concentration range into low, medium and high three intervals, and corresponds to different dry-wet ratio reference values. The low concentration interval (less than 50% of the design influent concentration) adopts a dry-wet ratio of 2:1, that is, the dry time accounts for 67% of the total cycle, and the wet time accounts for 33%; the medium concentration interval (50%-150% of the design concentration) adopts a standard ratio of 1:1; the high concentration interval (more than 150% of the design concentration) adopts a ratio of 1:2, that is, the dry time accounts for 33% of the total cycle, and the wet time accounts for 67%. The transition interval adopts linear interpolation to avoid sudden changes in the dry-wet ratio. The feedback adjustment mechanism fine-tunes the dry-wet ratio according to the effluent ammonia nitrogen concentration, and increases the wet time ratio when the effluent exceeds the standard. Based on the implementation of the dynamic adjustment strategy based on concentration response, the dry-wet ratio parameters are generated.

[0058] In some embodiments, the method further comprises: determining a dry-wet ratio parameter based on the ammonia nitrogen concentration data; and formulating a dissolved oxygen control scheme based on the dry-wet ratio parameter.

[0059] According to the determined dry-wet ratio parameter, an adaptive operation schedule matching it is formulated. The core of the operation schedule is to convert the abstract dry-wet ratio into specific time nodes and duration. For the standard dry-wet ratio of 1:1, 4 complete cycles are arranged within 24 hours, each cycle being 6 hours, with 3 hours of drying and 3 hours of humidification; for the high ammonia nitrogen ratio of 1:2, the drying time is compressed to 2 hours and the humidification time is extended to 4 hours; for the low ammonia nitrogen ratio of 2:1, the drying time is 4 hours and the humidification time is 2 hours. The time schedule also needs to consider the internal structure of the humidification stage, including three sub-stages of rapid water filling period, full water standing period and slow drainage period. The duration of the water filling period depends on the water inflow and the target water level, which is determined by the flow calculation of the main water inlet pipe (1); the standing period is the main biochemical reaction period, accounting for 50%-60% of the humidification time; the drainage period is calculated according to the optimal emptying speed determined in the foregoing. Although there is no water flow in the drying stage, biochemical reactions are still taking place inside the substrate, and sufficient time is needed to complete the nitrogen transformation. The accuracy of the time schedule is controlled at the minute level, and the precise control is realized through the PLC timer. The time buffer in the transition period prevents the impact load when the stage switches. Through the conversion of dry-wet ratio to specific time parameters, an adaptive operation time schedule is formulated.

[0060] Based on the adaptive operation time schedule, the water quality characteristics and system operation state are comprehensively considered to generate a targeted operation scheme. The design principle of the water quality response type operation scheme is to dynamically adjust the operation details of each stage according to the real-time monitored water quality parameters. In the period of high ammonia nitrogen concentration, multi-point dispersed water filling is adopted in the water filling stage, and uniform water distribution through the branch pipe system (4) reduces local impact; the standing stage appropriately opens the water flow regulating valve (3) to maintain a weak internal circulation to promote mass transfer; the drainage stage controls the opening degree of the flow control valve (20) to adopt a slow drainage mode to extend the hydraulic retention time. Under medium concentration conditions, the standard operation program is executed, and each valve operates according to the preset parameters. In the low concentration period, a fast filling and draining mode can be adopted to shorten the hydraulic retention time and reserve the treatment capacity for the high concentration period. The operation scheme also includes measures to deal with abnormal situations, such as immediately extending the standing time of the current cycle when the ammonia nitrogen in the inflow water suddenly rises; in the case of continuous low concentration, some cycles can be temporarily skipped for system maintenance. The influence of water temperature on the operation scheme is reflected by adjusting the water filling flow rate, which is reduced to reduce the scouring of the biological membrane at low temperature. Real-time data provided by the conductivity sensor (29) and the ORP sensor (30) are used for dynamic optimization of the scheme. Through the establishment of multi-parameter coordination and dynamic response mechanism, a water quality response type operation scheme is formulated.

[0061] The oxygen concentration changes in each stage were recorded continuously by the dissolved oxygen online monitoring system while implementing the water quality response operation scheme, and different trends were identified and marked. The dissolved oxygen monitoring probe was arranged at multiple depths of the wetland, including the surface layer (0-10 cm), the middle layer (20-30 cm), and the bottom layer (40-50 cm), to monitor the spatial and temporal distribution of oxygen comprehensively. The rapid rising trend mainly occurred in the initial drainage stage, when the water level decreased rapidly, air quickly entered the upper layer of the substrate, and the dissolved oxygen concentration increased from nearly 0 mg / L to 6-8 mg / L within 30 minutes, with an upward rate exceeding 0.2 mg / L / min. The slow rising trend occurred in the late drainage stage and the entire drying stage, and oxygen gradually penetrated to the deep layer through diffusion, with an upward rate decreasing to 0.02-0.05 mg / L / min, which could last for several hours. The downward trend occurred during the water filling stage and the standing period, and the dissolved oxygen concentration continued to decrease due to microbial oxygen consumption and water isolation from air, reaching below 0.5 mg / L in the bottom layer, forming an anoxic environment suitable for denitrification. The identification of trend turning points is crucial for developing control strategies, as the transition from rising to plateau indicates that reoxygenation at that depth is basically complete, and the transition from plateau to decline indicates that the oxygen consumption process dominates. The oxygen concentration changes at different depths have a time lag, with the surface layer leading the deep layer, and the lag time reflecting the oxygen transfer rate. After multi-depth monitoring and trend identification, the oxygen concentration change trends were marked.

[0062] According to the marked oxygen concentration change trends, the reoxygenation effect was evaluated from multiple dimensions. The reoxygenation depth was determined by analyzing the time when the dissolved oxygen concentration at different depths reached the 2 mg / L threshold, which was considered the minimum requirement for normal metabolism of aerobic microorganisms. The reoxygenation in the rapid rising trend stage mainly concentrated in the surface and upper-middle layers, with a depth of 40%-50% of the total depth; the reoxygenation in the slow rising stage gradually expanded to the deep layer, eventually reaching a depth of 70%-80%. The reoxygenation rate was obtained by calculating the increment of oxygen concentration per unit time, and the rate difference in different stages reflected the transition of reoxygenation mechanisms. The oxygen distribution uniformity was evaluated using the coefficient of variation method, which calculated the dispersion degree of oxygen concentration at different depths at the same time. A system with good uniformity is conducive to stable biological treatment. The reoxygenation sustainability was evaluated by analyzing the maintenance time of oxygen concentration during the drying stage, and the longer the duration, the more sufficient the time window for aerobic reaction. The reoxygenation effect is also closely related to the wet-dry ratio, as too long wetting time will limit the reoxygenation depth, and too short drying time will affect the sufficiency of reoxygenation. The effect of temperature on reoxygenation is reflected by the change in oxygen saturation, and the oxygen solubility increases at low temperatures, resulting in better reoxygenation effect under the same operating conditions.

[0063] Based on the specific characteristic parameters revealed by the evaluation of reoxygenation effect, a matching oxygenation period control scheme is developed. The reoxygenation depth data shows that the rapid stage only reaches 40-50% depth, while the slow stage can reach 70-80%, according to which the oxygenation process is designed as a two-stage mode: the rapid oxygenation stage uses the high reoxygenation rate characteristics, and the time length is set to 0.5-1 hour, so that the surface and middle layers rapidly reach 6-8 mg / L; the slow oxygenation stage extends to 70-80% depth according to the characteristics, and is extended to 1-2 hours to ensure deep reoxygenation. Variance coefficient analysis shows that uneven oxygen distribution will affect the treatment effect, so a homogenization transition period is added after rapid oxygenation, and the drainage speed is reduced to promote lateral diffusion of oxygen. The reoxygenation persistence evaluation shows that the oxygen concentration can be maintained for 2-3 hours in the dry stage, so the natural deoxygenation stage is set to 0.5-1 hour, which fully utilizes the residual oxygen and creates conditions for subsequent anoxic. Temperature impact analysis shows that at low temperature, the oxygen solubility increases but the microbial activity decreases, so the winter scheme will extend the maintenance oxygenation stage by 30%, and shorten it by 20% in summer to prevent excessive aeration. The wet-dry ratio impact data guides the setting of the wet period, when it is detected that the wet time is too long to limit the reoxygenation depth, the static period is automatically shortened by 10-15 minutes. The abnormal response mechanism adjusts according to the real-time monitoring value of the reoxygenation rate, and when the rate is lower than 60% of the standard value, the drainage speed is immediately increased. Based on the quantitative analysis and optimization configuration of the reoxygenation effect parameters, the dissolved oxygen control scheme is generated.

[0064] In step S140, the oxygen utilization status is obtained by analyzing the metabolic response of the microbial community to the dissolved oxygen control scheme, the microbial activity region distribution is determined based on the oxygen utilization status, the vertical stratified biological reaction zone is planned based on the activity region distribution, and the nitration and denitrification partition strategy is generated. The combination of fillers and plants is configured according to the nitration and denitrification partition strategy.

[0065] Specifically, the metabolic response characteristics of different bacterial communities in each stage were analyzed by using the dissolved oxygen control scheme. The dissolved oxygen control scheme divides the cycle into four stages: rapid oxygenation, maintenance oxygenation, natural oxygen reduction, and anoxic maintenance. The oxygen concentration in each stage directly affects the selection of microbial metabolic pathways. Nitrifying bacteria showed the highest ammonia oxidation activity in the rapid oxygenation stage (dissolved oxygen 6-8 mg / L), and the metabolic intensity was evaluated by detecting the generation rate of nitrite and nitrate; nitrification proceeded stably in the maintenance oxygenation stage, but the rate decreased slightly; the activity of nitrifying bacteria decreased with the decrease of oxygen concentration in the natural oxygen reduction stage; nitrification basically stopped in the anoxic maintenance stage. The metabolic response of denitrifying bacteria showed the opposite trend, and they showed the strongest denitrification capacity in the anoxic maintenance stage, and their activity was evaluated by monitoring the removal rate of nitrate nitrogen and the amount of nitrogen produced. Heterotrophic bacteria maintained a certain activity throughout the cycle, but the metabolic products were different under different oxygen environments. Under aerobic conditions, they mainly carried out mineralization, and under anoxic conditions, they participated in the denitrification process and provided carbon sources. The metabolic rate and dissolved oxygen concentration showed a typical saturation curve relationship. When the dissolved oxygen was higher than 4 mg / L, the nitrification rate tended to be stable, and when it was lower than 1 mg / L, denitrification began to dominate. The spatial and temporal distribution of bacterial community activity was monitored by in-situ fluorescence probe technology, and the response curve of oxygen concentration-bacterial community activity was established. The oxygen penetration law at different depths showed that the oxygen could reach a depth of 15 cm in the oxygenation period, and the anaerobic state was maintained below 35 cm in the anoxic period. Through quantitative analysis of the metabolic characteristics of bacterial communities and determination of the oxygen penetration depth, the oxygen utilization status was obtained.

[0066] Based on the oxygen utilization data, the distribution of microbial activity in the vertical profile of the wetland was determined. The oxygen utilization indicated that the oxygen penetration depth during the aeration period was 15 cm. Combined with the dissolved oxygen requirement of nitrifying bacteria (> 2 mg / L), it was determined that the 0-15 cm zone was the high-activity zone of nitrifying bacteria. The oxygen concentration in the 15-35 cm zone fluctuated between 0.5-2 mg / L, which was suitable for the survival of facultative bacteria, forming a simultaneous nitrification and denitrification zone. Below 35 cm, the oxygen concentration was maintained at <0.5 mg / L for a long time, becoming the dominant area of denitrifying bacteria. The accurate definition of the active area was obtained through continuous monitoring by microelectrodes. The nitrifying bacteria activity in the 0-15 cm depth accounted for more than 65% of the total microbial activity, which was defined as the aerobic zone. The facultative bacteria in the 15-35 cm depth accounted for more than 50%, which was defined as the facultative zone. The anaerobic bacteria in the 35-50 cm depth accounted for more than 70%, which was defined as the anaerobic zone. The transition zone between the zones was about 2-3 cm thick, which was identified by the oxidation-reduction potential (ORP) gradient. The ORP in the aerobic zone was >300 mV, in the facultative zone was between -100 and +100 mV, and in the anaerobic zone was <-200 mV. The horizontal distribution of activity was relatively uniform, but there were local high-activity points in the influent area and the plant root dense area. In the time dimension, the active area migrated periodically with the dry-wet alternation. During the dry period, the active area moved down 3-5 cm, and during the wet period, the active area moved up 2-3 cm. The vertical distribution pattern of functional bacteria was highly consistent with the oxygen gradient, forming a stable layered structure. The vertical stratification of microbial activity and the division of functional zones determined the distribution of microbial activity in the 0-15 cm aerobic zone, 15-35 cm facultative zone, and 35-50 cm anaerobic zone.

[0067] According to the distribution of microbial activity zones, the corresponding biological reaction zone space configuration is planned. The aerobic zone (0-15 cm) undertakes the main nitrification function, and the design focus is to ensure sufficient oxygen supply and nitrifying bacteria attachment space. The hydraulic load of this layer is controlled at 0.8-1.2 m³ / (m²·d) to ensure sufficient contact time. A multi-point water distribution system is set up to avoid local scouring affecting the stability of the biofilm. Air permeable pipe network is set at the bottom to strengthen the natural reoxygenation capacity. The facultative zone (15-35 cm) is the transition zone between nitrification and denitrification, and needs to create an oxygen concentration gradient environment. The upper part (15-25 cm) maintains a micro-aerobic state to support residual nitrification, and the lower part (25-35 cm) creates an anoxic environment to promote denitrification. An internal circulation system is designed to return the nitrification liquid produced in the aerobic zone to the middle of this zone at a ratio of 1:1. A partition structure is added to prolong the water flow path and improve the removal rate of nitrate nitrogen. The anaerobic zone (35-50 cm) is specially designed to strengthen the denitrification and anaerobic ammonia oxidation processes. The dense design prevents the rapid downward infiltration of the oxygen-rich water from the upper layer. A water collection pipe system is set at the bottom to control the effluent flow rate at 0.05-0.1 m / h. The anaerobic stability of this area is maintained, and the ORP is maintained below -200 mV. Transition layers are set between each reaction zone to avoid hydraulic jumps using a gradual change in particle size. The transition layer thickness is 2-3 cm and is consistent with the interface of the active area. The optimization of vertical flow state is achieved by setting guide plates and water distributors to ensure that the residence time of water flow in each reaction zone meets the biochemical reaction requirements. Based on the functional positioning and engineering design of microbial activity partition, a nitrification-denitrification partition strategy is generated.

[0068] Based on the function positioning of the three-layer reaction zone determined by the nitration-denitrification partition strategy, the corresponding filler and plant combination are configured. The filler in the aerobic zone (0-15 cm) is selected as high porosity material to ensure oxygen transmission, and the main part is zeolite with a particle size of 10-12 mm, with a porosity of 45% and a specific surface area of 850 m² / m³, which provides sufficient attachment space for nitrifying bacteria; supplemented with 20% of the ceramic to enhance the structural stability; the surface 3 cm is paved with coarse sand to prevent the loss of filler. The plant is selected as reed with strong oxygen excretion capacity, with a planting density of 30 plants / m², and the root depth is controlled within 12 cm to avoid penetrating into the facultative zone; the radial oxygen excretion of reed root can increase the rhizosphere dissolved oxygen to 4-5 mg / L, and the nitrification effect is strengthened. The filler in the facultative zone (15-35 cm) is designed in double layers to adapt to the oxygen gradient change, the upper layer (15-25 cm) uses volcanic rock with a particle size of 6-8 mm, with a porosity of 35%, to create a micro-aerobic environment; the lower layer (25-35 cm) mixes shale ceramic and 5% iron-carbon filler, and the Fe²⁺ produced by the micro-electrolysis of iron-carbon can be used as the electron donor for denitrification. This zone is planted with canna, with a root depth of 20-30 cm, which is just distributed in the facultative zone, and the root exudate yield reaches 2.5 kg / m² per year, providing carbon source for denitrification. The filler in the anaerobic zone (35-50 cm) focuses on creating a stable anaerobic environment, the bottom layer is paved with gravel with a particle size of 4-5 mm as a support layer; the middle layer is filled with river sand with a particle size of 2-3 mm, which has low permeability to maintain anaerobic state; the upper layer is mixed with 10% broken straw as slow-release carbon source, and the C / N ratio is controlled at 25:1. This zone does not have plants, and maintains a pure anaerobic environment. The filler is filled by layer compaction process, and the compaction degree of each layer is controlled at 85% to ensure that there is no settlement during long-term operation. The precise matching of the partition function demand and the material characteristics finally completes the configuration of the filler and plant combination.

[0069] In step S150, the water quality sensing type siphon trigger point is set based on the filler and plant combination, the plant root exudate concentration change is monitored according to the water quality sensing type siphon trigger point, and the biological feedback regulation parameter is obtained by self-adaptively adjusting the water quality sensing type siphon trigger point based on the root exudate concentration change.

[0070] Specifically, according to the spatial distribution characteristics of the filler and plant combination, water quality sensing siphon trigger points are set at key positions. In the three-layer structure formed by the filler and plant combination, the rhizosphere of the reed in the aerobic zone and the dense root zone of the canna in the facultative zone are the areas with the strongest biological activity. Setting trigger points at these positions can sensitively reflect the biochemical state of the system. The main trigger point is set in the middle of the facultative zone (25 cm deep), where the canna root exudate concentration is the highest, and it is in the sensitive area of the aerobic-anoxic transition; the auxiliary trigger points are set at the bottom of the aerobic zone (15 cm) to monitor the accumulation of nitrification products and at the top of the anaerobic zone (35 cm) to monitor the denitrification process. The sensor combination of the trigger point includes ORP electrode, pH probe, conductivity sensor, and dissolved organic carbon (DOC) detector, among which the DOC detector is specifically used to monitor root exudates. The installation of the sensor takes into account the characteristics of the filler. In the area of large-particle fillers such as zeolite and volcanic rock, a sheath is used to protect against particle wear; in the area of fine fillers such as river sand, a filter screen is set to avoid blockage. The trigger logic design is based on multi-parameter fusion. When the DOC concentration exceeds the set threshold and the ORP is within a certain range, the siphon is triggered, realizing the coupling of biological and hydraulic processes. The data acquisition frequency is set to every 5 minutes to ensure the capture of the dynamic changes of root exudates. Through the optimized arrangement of trigger point position and sensor configuration, the water quality sensing siphon trigger point is set to monitor the changes in plant root exudate concentration.

[0071] In some embodiments, the adaptive adjustment of the water quality sensing siphon trigger point based on the root exudate concentration change obtains a biological feedback regulation parameter, including: monitoring the root exudate concentration change to determine the plant growth state; determining the siphon trigger water level adjustment requirement based on the plant growth state; adjusting the water quality sensing siphon trigger point according to the adjustment requirement to obtain an adjusted siphon trigger point; and generating a biological feedback regulation parameter based on the difference between the adjusted siphon trigger point and the water quality sensing siphon trigger point.

[0072] The concentration of root exudates was monitored continuously by a sensor combination of water quality and siphon trigger point. The main components of reed root exudates were organic acids, sugars and amino acids, and the DOC concentration reached 80-120 mg / L in the growing season and decreased to 20-30 mg / L in the dormant period. The main components of canna root exudates were polysaccharides and proteins, and the concentration ranged from 60 to 150 mg / L. The diurnal variation of exudate concentration showed that the exudation increased during the day when photosynthesis was active and decreased at night, with the peak usually occurring at 14:00-16:00. Seasonal variation was more obvious, with the exudate concentration rapidly increasing in the spring, maintaining a high level in the summer, gradually decreasing in the autumn, and reaching a minimum in the winter. Concentration mutations indicated changes in plant physiological state, such as a sharp increase in specific components in exudates when stressed. Principal component analysis was used to identify changes in exudate composition, with the first principal component usually related to plant growth vigor and the second principal component reflecting stress response. The C / N ratio of exudates from plants in the growing season was maintained at 15-20, increased to more than 25 when nutrients were deficient, and possibly decreased to less than 10 when diseased. Based on the multi-dimensional analysis of root exudates, the growth state of plants was determined.

[0073] Based on the information obtained by monitoring the growth state of plants, the adjustment requirements of the siphon trigger water level were determined. During the growing season, the concentration of root exudates was high, the metabolic activity of microorganisms was active, and the oxygen consumption was increased, so the siphon trigger frequency needed to be increased to strengthen the oxygenation, and therefore the trigger water level should be lowered to start the siphon earlier. During the dormant period, the plant metabolism was slow, the exudates were reduced, and the microbial activity was decreased, so the trigger water level could be appropriately increased to prolong the wetting time. Under nutrient stress, plants would increase the secretion of specific organic acids to activate soil nutrients, and at this time the wetting period needed to be extended to promote nutrient dissolution and absorption, and the trigger water level should be adjusted by 5-8 cm. When diseased, plants would secrete antibacterial substances, and the water body needed to be updated to avoid the accumulation of pathogenic bacteria, and the trigger water level should be adjusted by 3-5 cm. The effect of temperature was reflected by the growth rate of plants, and during the high temperature period, the growth was fast and the exudates were more, so the trigger water level should be lowered accordingly. During the low temperature period, the opposite was true. Water quality factors were also taken into consideration, and when the nitrogen concentration of the incoming water increased, the trigger water level needed to be lowered even if the plant state was normal to increase the nitrification time. The quantification of adjustment requirements used a fuzzy logic method, with input variables including exudate concentration, C / N ratio, temperature, etc., and the output being the trigger water level adjustment amount. The comprehensive evaluation of plant physiological requirements and system operation requirements determined the adjustment requirements of the siphon trigger water level.

[0074] Based on the determined adjustment demand, the water quality sensing siphon trigger point is dynamically adjusted. Step-by-step correction is adopted, with an adjustment amplitude of 2-3 cm each time to avoid impact on the system caused by drastic changes. When it is judged that the trigger water level needs to be lowered, the control system automatically lowers the set value, while monitoring the system response after adjustment; if the plant state improves within 24 hours, the new setting is maintained, otherwise fine-tuning is continued. During the adjustment process, the linkage relationship between the main trigger point (25 cm deep) and the auxiliary trigger points is maintained, and when the main trigger point is lowered, the upper auxiliary trigger point (15 cm) is lowered by 70% of the amplitude, and the lower auxiliary trigger point (35 cm) is lowered by 50%, maintaining the gradient relationship between the trigger points. Limit constraints ensure that the adjustment does not exceed a reasonable range, with the highest trigger water level not exceeding 8 cm below the ground surface and the lowest not lower than 35 cm below the ground surface. The time response characteristics of the adjustment take into account the adaptation process of the plants, with fast adjustment used to respond to sudden stress and a time constant of 2-4 hours; slow adjustment is used for seasonal changes, with a time constant of 3-5 days. The siphon trigger point after adjustment is finally obtained through demand-oriented dynamic adjustment.

[0075] The difference between the adjusted siphon trigger point and the initial set value is analyzed to extract the biological feedback adjustment parameters. The difference analysis includes static offset and dynamic change, with the static offset reflecting the results of long-term adaptation, such as the average trigger water level being 4-6 cm lower than the initial value in summer; the dynamic change embodies the short-term response characteristics, such as the daily trigger water level fluctuation amplitude reaching 3-4 cm. The core of the adjustment parameters is to establish a "biological state-trigger adjustment" mapping relationship, and the parameter set includes: sensitivity coefficient α, representing the amount of trigger water level adjustment caused by unit change in secretion concentration, with a typical value of 0.05 cm / (mg / L); time lag coefficient τ, reflecting the delay time from detection of biological signals to trigger adjustment, generally 15-30 minutes; threshold parameter set {Cmin, Cmax, Ropt}, representing the minimum concentration, maximum concentration and optimal C / N ratio of trigger adjustment, respectively. Seasonal correction factors are obtained by fitting historical adjustment data, with a spring factor of 1.2, a summer factor of 1.0, an autumn factor of 0.9 and a winter factor of 0.7. Adaptive adjustment of feedback gain is achieved by evaluating the adjustment effect, with the gain gradually increasing when the plant state continuously improves, and vice versa. Based on the correlation analysis of biological signals and hydraulic control, the biological feedback adjustment parameters are finally obtained.

[0076] In step S160, based on the biological feedback adjustment parameters, the fast drainage mode and the slow infiltration mode are constructed simultaneously, and the fast drainage mode and the slow infiltration mode are analyzed for contradiction and cooperation to generate an intelligent tidal change mode, and the dry-wet alternation frequency is determined based on the intelligent tidal change mode.

[0077] Specifically, the control framework of the two drainage modes is constructed by using biofeedback regulation parameters. The fast drainage mode design emphasizes timeliness. When the biofeedback parameters indicate that the root exudate concentration is close to Cmax, the system determines that the plant metabolism is active and needs to strengthen oxygenation. The siphon pipe of the fast mode adopts a large pipe diameter design, and the siphon breaking water level is set at a lower position to ensure that the water level drops quickly. The negative pressure formed during the drainage process promotes air entrainment, and the surface filler is quickly exposed to the atmospheric environment. The slow infiltration mode focuses on uniformity and is suitable for the low metabolism period when the exudate concentration is close to Cmin. This mode controls the drainage rate through a flow limiting device, causing the water level to drop slowly and providing sufficient time for deep oxygen diffusion. The siphon pipe adopts a small pipe diameter or is provided with a throttle valve, and the breaking water level is set high to prolong the drainage duration. The triggering logic of the two modes is based on biofeedback but has opposite response characteristics. The fast mode pursues instantaneous response and is executed immediately after triggering. The slow mode introduces a time lag coefficient τ to avoid frequent switching. The calibration of mode parameters considers seasonal correction factors. The triggering threshold of the fast mode is lowered in the growing season, and the duration of the slow mode is extended in the dormant period. The mode recognition function is embedded in the control algorithm to determine whether the current running mode is normal through real-time water level change rate. Through the differential mapping of biological signals and hydraulic parameters, the fast drainage mode and the slow infiltration mode are constructed simultaneously.

[0078] In some embodiments, the contradictory synergy analysis of the fast drainage mode and the slow infiltration mode generates an intelligent tidal change mode, including: comparing the efficiency of the fast drainage mode and the slow infiltration mode to obtain mode advantage and disadvantage characteristics; constructing a complementarity analysis matrix based on the mode advantage and disadvantage characteristics; developing a mode switching strategy according to the complementarity analysis matrix; and generating an intelligent tidal change mode based on the mode switching strategy.

[0079] The advantages of the rapid drainage mode include: rapid surface reoxygenation, suitable for nitrification under high ammonia nitrogen load; complete hydraulic renewal, conducive to the rapid discharge of metabolic products; short response time, which can respond to water quality fluctuations in a timely manner. The disadvantages include: insufficient deep reoxygenation, anaerobic conditions may be maintained at the bottom; strong water flow scouring, which may disturb the stability of the biofilm; frequent use may cause water stress. The advantages of the slow infiltration mode include: good deep reoxygenation effect, sufficient time for oxygen to diffuse downward; uniform water distribution, conducive to plant root absorption; small biofilm disturbance, stable microbial community structure. The disadvantages include: relatively low treatment efficiency, not suitable for high load impact; a reducing environment may form at the surface; slow response, difficult to adjust quickly. The efficiency comparison also considers energy consumption factors. The rapid mode has high energy consumption per time but short operation time, while the slow mode has low energy consumption per time but long total time. The evaluation indicators of treatment effect include nitrogen removal rate, effluent stability, plant growth conditions, etc. The quantitative description of mode characteristics uses the radar chart method to display from multiple dimensions such as reoxygenation depth, treatment rate, energy consumption level, and biological stability. After systematic analysis and quantitative evaluation of the differentiated characteristics, the advantages and disadvantages of the modes are obtained.

[0080] Based on the identified advantages and disadvantages of the modes, a complementary analysis matrix of the two modes is constructed. The rows and columns of the matrix represent different operating conditions and performance indicators, respectively. The matrix elements quantify the applicability of each mode under specific conditions. The operating condition dimensions include: influent ammonia nitrogen concentration (high / medium / low), plant growth stage (flourishing / stable / dormant), seasonal factors (spring / summer / autumn / winter), and previous operation mode. Performance indicators include nitrification efficiency, denitrification efficiency, energy consumption indicators, and system stability. The nitrification efficiency of the rapid mode is highest under the condition of "high ammonia nitrogen + flourishing growth", and the energy consumption of the slow mode is optimal under the condition of "low load + dormant period". Complementarity is reflected by the difference between the matrix elements. A large difference indicates strong complementarity between the two modes, suitable for alternating use; a small difference can maintain a single mode. The non-diagonal elements of the matrix reflect the conversion cost between modes, including hydraulic adjustment time, biological adaptation period, etc. Time series complementary analysis finds that the rapid mode is suitable for daytime to match photosynthesis, and the slow mode is suitable for nighttime to match plant respiration rhythm. Eigenvalue decomposition of the matrix identifies the main complementary modes. The first eigenvector usually corresponds to "load-efficiency" complementarity, and the second eigenvector reflects "energy consumption-stability" balance. Through the structured organization of advantages and disadvantages and the quantification of complementary relationships, the complementary analysis matrix is obtained.

[0081] According to the complementary analysis matrix, the mode switching strategy is formulated, including: identifying the fast drainage advantage condition and the slow infiltration advantage condition based on the complementary analysis matrix; setting the pollutant concentration switching threshold according to the fast drainage advantage condition and the slow infiltration advantage condition; establishing the switching judgment rule based on the pollutant concentration switching threshold; and generating the mode switching strategy according to the switching judgment rule.

[0082] The advantage operation conditions of each mode are extracted by the complementary analysis matrix. The matrix analysis shows that the fast drainage is dominant under the following conditions: the influent ammonia nitrogen concentration exceeds the high threshold of the matrix, the plant root exudate C / N ratio is lower than Ropt, indicating insufficient nitrogen supply, the first sunny day after continuous rain requires fast reoxygenation, and the continuous operation of the slow mode in the early stage leads to enhanced surface reduction. The advantage conditions of slow infiltration include: the ammonia nitrogen concentration is in the low interval of the matrix, the plant enters the dormant period and metabolism slows down, the air temperature is low and the microbial activity is limited, and the previous fast drainage causes water deficit and needs to be supplemented. The boundary conditions are determined by cluster analysis, and the cluster centers of the fast mode and the slow mode are the typical advantage conditions. The cluster boundary is used for subsequent threshold setting. The condition weight is determined by principal component analysis, and the pollutant concentration usually accounts for the first principal component, and the plant state accounts for the second principal component. The identification of the advantage condition also considers dynamic factors, such as the fast mode must be interval a certain time before being used again to avoid excessive drying. After comprehensive analysis of the matrix characteristics and operation data, the fast drainage advantage condition and the slow infiltration advantage condition are obtained.

[0083] According to the identified advantage condition characteristics, the mode switching threshold of the pollutant concentration is set. The determination of the ammonia nitrogen concentration threshold is based on the intersection of the treatment capacity curves of the two modes. When the influent ammonia nitrogen concentration is higher than the intersection value, the fast mode is more efficient, and when it is lower than the intersection value, the slow mode is more economical. The threshold setting adopts a double-layer structure: the first-level threshold is used for mode selection, the fast mode must be enabled when the ammonia nitrogen concentration is higher than NH4-high, the slow mode is preferred when the ammonia nitrogen concentration is lower than NH4-low, and the comprehensive judgment is made according to other conditions when the ammonia nitrogen concentration is between the two. The second-level threshold is used for mode maintenance to avoid frequent switching, and the switching dead zone width is set to ±20% of the first-level threshold. The COD / N ratio is used as an auxiliary switching index. A high ratio indicates that the carbon source is sufficient for denitrification, and the slow mode is preferred. A low ratio needs to be strengthened nitrification, and the fast mode is selected. The cumulative effect of total nitrogen concentration is handled by the moving average algorithm to prevent unnecessary switching triggered by instantaneous fluctuations. The dynamic adjustment mechanism of the threshold is based on the feedback of the treatment effect. If the effluent continues to exceed the standard, the switching threshold is automatically lowered to enable the enhanced mode in advance. The seasonal threshold correction considers the influence of temperature on microbial activity, and the threshold is generally raised in winter and moderately lowered in summer.

[0084] Based on the set concentration thresholds, a complete mode switching judgment rule system was established. The judgment rules adopted IF-THEN structure, and the main rules were based on pollutant concentrations: IF (NH4 > NH4-high AND COD / N < 2) THEN fast mode; IF (NH4 < NH4-low AND COD / N > 4) THEN slow mode. Auxiliary rules considered biological feedback: IF (root exudate concentration > 0.8Cmax AND last fast drainage time > 6h) THEN fast mode. Constraint rules prevented abnormal switching: IF (current mode running time < minimum duration) THEN maintain current mode. Priority rules handled conflict situations: biological stress signals > pollutant concentrations > energy optimization > other factors. The selection of switching timing avoided sensitive periods, such as avoiding starting fast drainage during the peak period of plant transpiration. The verification of rules was through historical data backtesting, checking the rule triggering frequency and switching effect. The handling rules for abnormal situations included: running based on time program when sensor fails; prioritizing system safety during extreme weather.

[0085] According to the established switching judgment rule system, corresponding mode switching strategies were developed. The core of switching strategies was to organize discrete judgment rules into continuous control logic. The main strategy was based on pollutant concentration rules: when "NH4 > NH4-high AND COD / N < 2" was triggered, the strategy was set to switch to fast mode immediately and maintain at least one complete cycle; when "NH4 < NH4-low AND COD / N > 4" was met, switching to slow mode was allowed but the preconditions needed to be checked. Timing strategies handled the transition relationship between modes: at least one slow cycle must be inserted after fast mode to avoid excessive drying; a mandatory slow mode was inserted between two consecutive fast modes to protect system water balance. Combination strategies determined the mode sequence according to the triggering of different rules. When biological feedback rules conflicted with concentration rules, weighted decision was adopted, with biological stress weight 0.6 and pollutant concentration weight 0.4. Switching timing strategies stipulated that mode transition could only be executed at the end of the current cycle, avoiding processing interruptions caused by mid-transition switching. Prevention strategies addressed rule boundary situations: when parameters were close to threshold ±10% range, switching was prepared in advance but not executed until the trend was confirmed. Abnormal handling strategies addressed situations not covered by the rule set, setting the default mode sequence "slow-fast-slow" as the basic rhythm. The expression of strategies used state transition diagrams, with nodes representing running modes and edges representing switching conditions and actions. Through the logical organization and timing arrangement of judgment rules, mode switching strategies were generated.

[0086] The characteristics and switching strategies of the two drainage modes are combined to automatically select and combine the two basic modes according to real-time conditions to form the optimal tidal rhythm. The basic rhythm modes include: the regular mode "fast-slow-slow" cycle, suitable for general operating conditions; the enhanced mode "fast-fast-slow", to cope with high load impact; the energy-saving mode "slow-slow-slow", for low load period; the transition mode "fast-slow" alternation, for conditions of rapid change period. The intelligent scheduling algorithm is based on the load prediction of the next 24 hours, and the mode combination is planned in advance. The prediction model uses historical data and weather forecast information. The intelligent optimization of mode conversion considers the conversion cost. Continuous use of the same mode can reduce switching loss, but too long will reduce the processing flexibility. The intelligent adjustment range of the tidal cycle is set to 4-8 hours. In high load period, the cycle is shortened to increase the processing frequency, and in low load period, the cycle is lengthened to reduce energy consumption. The intelligent response mechanism of abnormal events can identify sudden pollution, heavy rain and other situations, and temporarily adjust to emergency mode. The intelligent learning function continuously optimizes the mode combination rules by analyzing historical optimal operation cases, and finally generates an intelligent tidal variation mode.

[0087] In some embodiments, the determination of the dry-wet alternating frequency based on the intelligent tidal variation mode includes: extracting dry-wet cycle parameters based on the intelligent tidal variation mode; calculating the number of cycles per unit time according to the dry-wet cycle parameters; evaluating the processing effect based on the number of cycles to generate a frequency optimization index; and determining the dry-wet alternating frequency according to the frequency optimization index.

[0088] Key dry-wet cycle parameters are extracted from the operation records of the intelligent tidal variation mode. Cycle parameter extraction is achieved through time series analysis to identify periodic patterns in water level data. Main parameters include: wet duration Tw, from water inflow to drainage start; dry duration Td, from drainage end to next water inflow; complete cycle length Tc = Tw + Td; dry-wet ratio R = Td / Tw. These parameters are dynamically changing in intelligent mode, with relatively longer Td in fast drainage mode and larger Tw proportion in slow infiltration mode. Statistical characteristics of parameters are calculated through sliding window, including mean, standard deviation, coefficient of variation, etc., reflecting the stability of system operation. Daily variation pattern shows frequent dry-wet conversion during the day and relatively longer cycle at night. Weekly variation is related to water inflow load fluctuation, with shorter cycle on weekdays and appropriately longer cycle on weekends. Seasonal variation is obtained through long-term data fitting to establish the temperature-cycle response relationship. Parameter extraction also includes identification and elimination of abnormal cycles to ensure the representativeness of statistical results.

[0089] Based on the extracted cycle parameters, the number of wet-dry cycles at different time scales was calculated. The daily cycle number Nd=24 / Tc, reflecting the daily treatment intensity of the system; the weekly cycle number Nw=168 / Tc, used to evaluate the weekly treatment capacity; the monthly cycle number Nm=∑(24×30 / Tc,i×Pi), where Tc,i is the cycle of the i-th mode, and Pi is the probability of using this mode. The actual value of the cycle number is usually lower than the theoretical calculation value, because mode switching and system maintenance will occupy time. The criteria for effective cycles include: completing a complete filling-reaction-draining process, the wet-dry ratio being within a reasonable range, and the water quality improvement being obvious. Statistical analysis shows that the daily cycle number is 3-6 times when the system runs most stably, too high will cause biological stress, and too low will be insufficient in treatment capacity. The distribution characteristics of the cycle number are shown by a histogram, and the normal distribution indicates the system operation rules, and the skew distribution suggests the need for optimization. The instantaneous cycle frequency is obtained by differential calculation, f=1 / Tc, which is used to monitor the system state in real time. The cycle efficiency η is defined as the ratio of the effective cycle number to the total cycle number, reflecting the actual utilization rate of the system.

[0090] According to the correlation analysis of cycle number and treatment effect, an evaluation system for frequency optimization was established. The treatment effect evaluation is carried out from multiple angles: water quality stability, by calculating the coefficient of variation of water quality indicators at different cycle frequencies; pollutant removal efficiency, by drawing the cycle number-removal rate curve to identify the optimal frequency interval; energy efficiency, by calculating the energy consumption per unit pollutant removal with frequency change. Biological response indicators include: plant growth rate at different frequencies; correlation between microbial activity and cycle frequency; adaptability of root development degree to frequency. System stability evaluation considers: the impact of frequent cycles on the structure of the filler; the stability of biofilm attachment at different frequencies; the disturbance degree of hydraulic conditions to the system. The optimization index adopts a comprehensive scoring method, F=∑(wi×fi), where wi is the weight of each sub-index, and fi is the dimensionless score. The weight setting is determined by the analytic hierarchy process, with the highest weight for treatment effect, followed by energy consumption and stability. Through multi-dimensional effect evaluation and comprehensive optimization analysis, the frequency optimization index is generated.

[0091] The optimal frequency is determined by multi-objective optimization method, which balances the treatment effect, energy consumption and system stability. The reference frequency is set according to the design treatment capacity, and the dry-wet alternating period is generally controlled within 6-8 hours, corresponding to 3-4 times per day. The dynamic adjustment strategy adjusts the frequency according to the real-time optimization indicators: when the treatment effect indicator decreases, the frequency is appropriately increased to increase the treatment opportunity; when the energy consumption indicator exceeds the limit, the frequency is reduced to save energy; when the stability indicator is abnormal, the frequency is temporarily fixed to avoid disturbance. The upper and lower limits of the frequency are based on the physical limitations of the system, with the highest frequency limited by the siphon water filling time and the lowest frequency ensuring basic treatment requirements. The time-of-use frequency strategy takes full advantage of the peak-valley difference, and the frequency can be appropriately increased during the day when the light is sufficient, and reduced at night to synchronize with the plant physiological rhythm. Based on the multi-objective decision-making of the optimization indicators, the dry-wet alternating frequency is finally determined.

[0092] In step S170, the temperature variation trend is obtained by analyzing the dry-wet alternating frequency, and the temperature response type endogenous carbon release method is constructed based on the temperature variation trend. Based on the carbon release method, a full-temperature-range denitrification guarantee strategy is generated, and the self-adaptive control of the tidal flow of the constructed wetland is completed.

[0093] Specifically, under the determined dry-wet alternating frequency operation mode, the variation law of water temperature in different seasons and functional areas is analyzed. In the aerobic zone (0-15 cm), multiple temperature monitoring points are set along the interface between zeolite and ceramic filler layer, and high-precision temperature sensors are used to record in real time. In the facultative zone (15-35 cm), temperature monitoring points are set at the upper part of the volcanic rock layer and the lower part of the shale ceramic mixed layer to capture the temperature gradient change in the transition zone. In the anaerobic zone (35-50 cm), monitoring points are arranged along the interface between gravel and river sand filler layer to focus on the stability of deep layer temperature. Through continuous monitoring, the temperature variation characteristics in four seasons are recorded: in summer, the surface water temperature is significantly higher than the deep layer, the vertical temperature difference reaches the maximum value, and the temperature gradient promotes convection circulation; in winter, temperature inversion occurs, the bottom temperature is slightly higher than the surface, and the vertical temperature difference is significantly reduced; in spring and autumn, the temperature distribution is relatively uniform, and the vertical temperature difference is at an intermediate level. The relationship analysis between microbial activity and water temperature shows that: the nitrifying bacteria in the surface layer have the highest activity within the suitable temperature range, and the nitrification rate reaches the peak value; when the temperature drops below the low temperature threshold, the nitrification rate decreases by more than half; the suitable temperature range of denitrifying bacteria in the middle and bottom layers is slightly lower than that of nitrifying bacteria, and they perform best at moderate temperatures; at very low temperature, the denitrification rate drops to less than one-third of the normal level. The temperature response characteristics under different dry-wet alternating frequencies show that: in the aerobic zone, the surface temperature increases significantly under high-frequency alternating conditions, which is conducive to nitrification; in the anaerobic zone, the bottom temperature fluctuation range is small under low-frequency alternating conditions, maintaining a stable denitrification environment. Through temperature data analysis of each functional area under different dry-wet alternating frequencies, the temperature variation trend is obtained.

[0094] According to the seasonal characteristics and vertical distribution revealed by the temperature change trend, a regulation method for promoting endogenous carbon release was constructed. Temperature monitoring showed that the vertical temperature difference was large in summer, the temperature was inverted in winter, the temperature was uniform in the transition season, and the high-frequency alternating temperature fluctuation was intense, etc. According to this, a differentiated carbon source regulation strategy was designed. In summer, the surface layer high temperature promotes the rapid mineralization of organic matter but is easy to over-consume, and the regulation method adopts the "surface excitation-deep protection" mode: during the daytime high temperature period, start rapid drainage, use the double stress of high temperature and dryness to promote the release of a large amount of organic acid from the root system of reed, but strictly control the dry time to prevent excessive loss; the deep layer maintains a longer wet period, uses the low temperature environment to slow down the straw degradation rate, and makes it as a carbon source reserve to release slowly. The temperature inversion in winter creates conditions for the activation of deep carbon sources, and the regulation is changed to "deep reinforcement-surface supplement": through slow infiltration to prolong the residence of water in the deep layer, combined with relatively high temperature to promote the anaerobic degradation of straw to release small molecular organic acids; the surface layer causes low temperature stress by prolonging the dry period, inducing plants to secrete carbohydrates, amino acids and other antifreeze substances as supplementary carbon sources. In the transition season, the temperature distribution is uniform, and the "full layer pulse regulation" is adopted: use short dryness during the daytime temperature rise period to accelerate the desorption of organic matter and root secretion; quickly fill water at night, and the low temperature environment slows down the consumption rate of newly released carbon sources. The temperature daily fluctuation produced by high-frequency dry-wet alternation is fully utilized through "time optimization": the drainage start is set in the temperature rise period, so that the dry process coincides with the peak temperature, maximizing the instantaneous release amount of carbon source; the water filling time is selected in the temperature drop period to protect the carbon source from rapid consumption. Through systematic analysis, the corresponding relationship between temperature-carbon source-release rate was determined: the carbon source release rate is the fastest under high temperature conditions in summer but needs to control the time length, the release is slow under low temperature in winter but the action time can be prolonged, and the release rate is moderate and stable in the transition season. Based on the precise matching of temperature characteristics and release mechanism, a water temperature responsive endogenous carbon release method was constructed.

[0095] The seasonal carbon source supply pattern determined based on the carbon release method generates a denitrification guarantee strategy covering the whole temperature range throughout the year. The carbon release method reveals the law that carbon source is released quickly but easily exhausted in summer, slowly but continuously in winter, and stably in the transition season, and accordingly corresponding guarantee measures are formulated. The winter cold period strategy aims at the serious decline of denitrification activity caused by low temperature, and adopts the "endogenous activation + exogenous supplement" mode: maximizing the utilization of temperature inversion phenomenon, promoting the accumulation of organic acids generated by anaerobic degradation by prolonging the deep wet period; the position of the pre-buried straw layer is optimized to the deep layer with relatively high temperature to maintain the basic degradation capacity; at the same time, cold-resistant denitrifying strains are introduced to strengthen the low-temperature treatment capacity. In the late winter and early spring, the low-temperature period takes advantage of the temperature rise trend, and the strategy is adjusted to "progressive strengthening": according to the gradual increase of carbon release rate, the drying period is shortened accordingly to balance the supply and consumption of carbon source; the short-term drying during the daily temperature peak period is used to strengthen the desorption of surface carbon source. In the spring and autumn, the carbon source supply and demand reach the best balance, and the strategy focuses on "precise coupling": the high-concentration carbon source release period is accurately matched with the anoxic environment formation period to fully exert the system design capacity. In summer, the high-temperature period faces the challenge of rapid consumption of carbon source, and the guarantee strategy adopts "pulse supply + continuous supplement": through the pulse mode of short-term drying-quick water filling, the release is stimulated while preventing excessive mineralization; the plant planting density is increased to provide continuous carbon source by root exudates. The emergency guarantee of extreme weather includes: heat preservation measures and carbon source pre-reserve during continuous low temperature; cooling protection and release frequency adjustment during continuous high temperature. The strategy implementation optimizes the carbon-nitrogen ratio in real time to ensure the stable progress of the denitrification process under the whole temperature range. The system integration of seasonal guarantee measures and emergency plans completes the adaptive control of the artificial wetland tidal flow.

[0096] In order to implement the artificial wetland tidal flow control method based on the siphon principle corresponding to the above-mentioned method embodiment, the corresponding functions and technical effects are realized. Referring to Figure 5 , Figure 5 A structural block diagram of a wetland tidal flow control device 200 based on the siphon principle is shown. For ease of illustration, only the parts related to the present embodiment are shown. The wetland tidal flow control device 200 based on the siphon principle provided by the present embodiment comprises:

[0097] The device construction module 201 is configured to select a suitable siphon device material to generate a component list, and obtain a siphon device layout based on the component list.

[0098] The drainage test module 202 is configured to perform continuous drainage test on the siphon device layout to obtain a continuous drainage rule, perform intermittent drainage test on the siphon device layout to obtain an intermittent drainage rule, compare the difference between the continuous drainage rule and the intermittent drainage rule to determine an optimal wetland emptying speed, and set an inflow control frequency according to the optimal wetland emptying speed.

[0099] The water quality regulation module 203 is configured to obtain ammonia nitrogen concentration data of the influent water based on water quality monitoring according to the control frequency of the influent water, dynamically adjust the dry-wet ratio parameter based on the ammonia nitrogen concentration data, and formulate a dissolved oxygen control scheme based on the dry-wet ratio parameter;

[0100] The partition optimization module 204 is configured to obtain oxygen utilization conditions by performing metabolic response analysis on the dissolved oxygen control scheme, determine the distribution of the microbial activity region based on the oxygen utilization conditions, plan vertical stratified biological reaction zones based on the distribution of the activity region to generate a nitrification-denitrification partition strategy, and configure the combination of the filler and the plant according to the nitrification-denitrification partition strategy.

[0101] The feedback regulation module 205 is configured to set a water quality sensing type siphon trigger point based on the combination of the filler and the plant, monitor the concentration change of the root exudates according to the water quality sensing type siphon trigger point, and obtain a biological feedback regulation parameter by adaptively adjusting the water quality sensing type siphon trigger point based on the concentration change of the root exudates.

[0102] The mode coordination module 206 is configured to simultaneously construct a rapid drainage mode and a slow infiltration mode based on the biological feedback regulation parameter, perform contradictory coordination analysis on the rapid drainage mode and the slow infiltration mode to generate an intelligent tidal change mode, and determine the dry-wet alternating frequency based on the intelligent tidal change mode.

[0103] The temperature guarantee module 207 is configured to obtain a temperature change trend by performing water temperature analysis on the dry-wet alternating frequency, construct a water temperature responsive endogenous carbon release method based on the temperature change trend, generate a full-temperature-range denitrification guarantee strategy based on the carbon release method, and complete adaptive control of the artificial wetland tidal flow.

[0104] The above-mentioned artificial wetland tidal flow control device 200 based on the siphon principle can implement the artificial wetland tidal flow control method based on the siphon principle of the above-mentioned method embodiment. The optional items in the above-mentioned method embodiment are also applicable to this embodiment, which will not be described in detail here. The remaining contents of the present embodiment can be referred to the contents of the above-mentioned method embodiment, which will not be described in detail in this embodiment.

[0105] The purpose of the above embodiments is to exemplarily reproduce and deduce the technical solutions of the present application, and to completely describe the technical solutions, purposes and effects of the present application. The purpose is to make the public understand the disclosure of the present application more thoroughly and comprehensively, and not to limit the protection scope of the present application.

[0106] The above embodiments are not an exhaustive enumeration based on the present application, and there can be many other unlisted embodiments. Any substitution and improvement made without violating the concept of the present application is within the protection scope of the present application.

Claims

1. A method for tidal flow control in a constructed wetland based on the siphon principle, characterized in that, The method comprises the following steps: selecting a suitable siphon device material to generate a component list, obtaining a siphon device layout based on the component list; performing continuous drainage test on the siphon device layout to obtain a continuous drainage rule, performing intermittent drainage test on the siphon device layout to obtain an intermittent drainage rule, comparing the difference between the continuous drainage rule and the intermittent drainage rule to determine an optimal wetland emptying speed, and setting an inflow control frequency according to the optimal wetland emptying speed; based on the inflow control frequency, water quality monitoring is performed to obtain inflow ammonia nitrogen concentration data, the dry-wet ratio parameter is dynamically adjusted based on the ammonia nitrogen concentration data, and the dissolved oxygen control scheme is formulated based on the dry-wet ratio parameter; performing microbial metabolic response analysis on the dissolved oxygen control scheme to obtain oxygen utilization status, determining the distribution of microbial activity area based on the oxygen utilization status, planning vertical stratified biological reaction zone based on the distribution of active area to generate nitrification and denitrification partitioning strategy, and configuring the combination of filler and plants according to the nitrification and denitrification partitioning strategy; based on the combination of filler and plants, setting a water quality sensing type siphon trigger point, monitoring the concentration change of plant root exudates according to the water quality sensing type siphon trigger point, and obtaining biological feedback adjustment parameters by adaptively adjusting the water quality sensing type siphon trigger point based on the concentration change of root exudates; based on the biological feedback adjustment parameters, simultaneously constructing a rapid drainage mode and a slow infiltration mode, performing contradictory collaborative analysis on the rapid drainage mode and the slow infiltration mode to generate an intelligent tidal change mode, and determining a dry-wet alternating frequency based on the intelligent tidal change mode; the contradictory collaborative analysis on the rapid drainage mode and the slow infiltration mode to generate an intelligent tidal change mode comprises: comparing the efficiency of the rapid drainage mode and the slow infiltration mode to obtain mode superior and inferior characteristics; constructing a complementarity analysis matrix based on the mode superior and inferior characteristics; formulating a mode switching strategy according to the complementarity analysis matrix, including identifying rapid drainage advantage conditions and slow infiltration advantage conditions based on the complementarity analysis matrix, setting pollutant concentration switching thresholds according to the rapid drainage advantage conditions and the slow infiltration advantage conditions, establishing switching judgment rules based on the pollutant concentration switching thresholds, and generating a mode switching strategy according to the switching judgment rules; and generating an intelligent tidal change mode based on the mode switching strategy; performing water temperature analysis on the dry-wet alternating frequency to obtain a temperature change trend, constructing a water temperature responsive endogenous carbon release method based on the temperature change trend, generating a full-temperature-range denitrification guarantee strategy based on the carbon release method, and completing adaptive control of artificial wetland tidal flow.

2. The method of claim 1, wherein, The method comprises the following steps: determining a siphon starting condition according to the component list; establishing a water level control parameter based on the siphon starting condition; designing an inflow and outflow path according to the water level control parameter to obtain a siphon device layout.

3. The method of claim 1, wherein, The method comprises the following steps: formulating an adaptive operation time schedule based on the dry-wet ratio parameter; generating a water quality responsive operation scheme according to the adaptive operation time schedule; monitoring dissolved oxygen and marking oxygen concentration variation trend for the water quality responsive operation scheme, the oxygen concentration variation trend including a rapid rising trend, a slow rising trend and a falling trend; evaluating re-oxygenation effect based on the oxygen concentration variation trend; determining a dissolved oxygen control scheme based on the re-oxygenation effect.

4. The method of claim 1, wherein, The comparison of the continuous drainage rule and the intermittent drainage rule determines the optimal wetland emptying speed, including: Comparing the continuous drainage rule and the intermittent drainage rule to identify the drainage rate variation characteristics; Based on the drainage rate variation characteristics, analyze the wetland re-oxygenation process to obtain re-oxygenation efficiency data; determine the appropriate emptying time according to the re-oxygenation efficiency data; determine the optimal wetland emptying speed based on the emptying time.

5. The method of claim 1, wherein, The adaptive adjustment of the water quality sensing type siphon trigger point based on the root exudate concentration change obtains biological feedback regulation parameters, including: Monitor the root exudate concentration change to determine the plant growth state; determine the siphon trigger water level adjustment requirement based on the plant growth state; adjust the water quality sensing type siphon trigger point according to the adjustment requirement to obtain the adjusted siphon trigger point; Based on the difference between the adjusted siphon trigger point and the water quality sensing type siphon trigger point, generate biological feedback regulation parameters.

6. The method of claim 1, wherein, The determination of the dry-wet alternation frequency based on the intelligent tidal change mode, including: Extract dry-wet cycle parameters based on the intelligent tidal change mode; Calculate the number of cycles per unit time according to the dry-wet cycle parameters; Based on the cycle number, generate a frequency optimization index by evaluating the processing effect; determine the dry-wet alternation frequency according to the frequency optimization index.

7. The method of claim 4, wherein, The analysis of the wetland re-oxygenation process based on the drainage rate variation characteristics to obtain re-oxygenation efficiency data, including: According to the drainage rate variation characteristics, identify the rapid drainage stage and the slow drainage stage; Based on the rapid drainage stage, determine the rate of air entering the wetland substrate to obtain the initial re-oxygenation intensity; Based on the slow drainage stage, monitor the diffusion depth of oxygen in the substrate to obtain the deep re-oxygenation degree; Integrate the initial re-oxygenation intensity and the deep re-oxygenation degree to generate re-oxygenation efficiency data.

8. A tidal flow control device for a constructed wetland based on the siphon principle, characterized in that including: The device construction module is used to select suitable siphon device materials to generate a component list, and to obtain a siphon device layout based on the component list; The drainage test module is used to perform continuous drainage test on the siphon device layout to obtain a continuous drainage rule, perform intermittent drainage test on the siphon device layout to obtain an intermittent drainage rule, compare the difference between the continuous drainage rule and the intermittent drainage rule to determine the optimal wetland emptying speed, and set the water inlet control frequency according to the optimal wetland emptying speed; The water quality regulation module is used to monitor the water quality based on the water inlet control frequency to obtain the water inlet ammonia nitrogen concentration data, dynamically adjust the dry-wet ratio based on the ammonia nitrogen concentration data to generate a dry-wet ratio parameter, and formulate a dissolved oxygen control scheme based on the dry-wet ratio parameter; The partition optimization module is configured to analyze the metabolic response of the bacterial community to the dissolved oxygen control scheme to obtain an oxygen utilization condition, determine a distribution of microbial activity regions based on the oxygen utilization condition, plan vertical layered biological reaction zones based on the distribution of the activity regions to generate a nitrification-denitrification partition strategy, and configure the combination of the filler and the plant according to the nitrification-denitrification partition strategy. The feedback adjustment module is configured to set a water quality sensing type siphon trigger point based on the combination of the filler and the plant, monitor changes in the concentration of root exudates of the plant according to the water quality sensing type siphon trigger point, and adaptively adjust the water quality sensing type siphon trigger point based on the changes in the concentration of the root exudates to obtain a biological feedback adjustment parameter. The mode coordination module is configured to simultaneously construct a rapid drainage mode and a slow permeation mode based on the biological feedback adjustment parameter, perform contradictory coordination analysis on the rapid drainage mode and the slow permeation mode to generate an intelligent tidal change mode, and determine a dry-wet alternating frequency based on the intelligent tidal change mode. The contradictory coordination analysis on the rapid drainage mode and the slow permeation mode to generate the intelligent tidal change mode includes: comparing the efficiency of the rapid drainage mode and the slow permeation mode to obtain mode superior and inferior characteristics; constructing a complementarity analysis matrix based on the mode superior and inferior characteristics; formulating a mode switching strategy according to the complementarity analysis matrix, including identifying rapid drainage advantage conditions and slow permeation advantage conditions based on the complementarity analysis matrix, setting a pollutant concentration switching threshold value according to the rapid drainage advantage conditions and the slow permeation advantage conditions, establishing a switching judgment rule based on the pollutant concentration switching threshold value, the switching judgment rule including a main judgment rule based on the pollutant concentration, an auxiliary judgment rule based on a biological feedback signal, and a constraint judgment rule for preventing abnormal switching, and generating a mode switching strategy according to the switching judgment rule; and generating an intelligent tidal change mode based on the mode switching strategy. The temperature guarantee module is configured to analyze the dry-wet alternating frequency to obtain a temperature change trend, construct a water temperature responsive endogenous carbon release method based on the temperature change trend, generate a full-temperature-range denitrification guarantee strategy based on the carbon release method, and complete adaptive control of the artificial wetland tidal flow.

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