Intelligent control system and method for secondary sedimentation tank

Abstract

The application discloses a kind of secondary sedimentation tank intelligent control systems, the secondary sedimentation tank intelligent control system includes data preparation, for the preliminary setting value of each control parameter of secondary sedimentation tank;Acquisition determination, data acquisition is carried out to control index, and compared with data preparation value, determination result;Regulation and control content, through the determination result of acquisition determination, the intelligent adjustment control of secondary sedimentation tank operation is carried out.The application further discloses a kind of secondary sedimentation tank intelligent control method.The secondary sedimentation tank intelligent control system and method greatly reduce artificial workload, reduce artificial cost, enhance the timeliness of regulation and control, improve the stability of secondary sedimentation tank operation, implement wisdom type water affair construction promotion work.

Description

Technical Field

[0001] This invention relates to secondary sedimentation tanks for wastewater treatment, and more specifically, to an intelligent control system and method for secondary sedimentation tanks. Background Technology

[0002] Secondary sedimentation tanks are an important component of activated sludge systems. Their main functions are to separate sludge, clarify and concentrate the mixed liquor, and return activated sludge. Their performance directly affects the effluent quality and the concentration of returned sludge in the activated sludge system. As a key structure in the activated sludge process for wastewater treatment, the secondary sedimentation tank's operating conditions and effluent quality have a crucial impact on the concentration of activated sludge in the biological system and subsequent effluent indicators. Currently, the sludge scraper operation protection device in the secondary sedimentation tank is relatively mature, but other monitoring systems for the secondary sedimentation tank are still relatively weak, mainly relying on manual inspections. On-site inspections and adjustments such as single-compartment effluent inspections, sludge discharge weir or sludge discharge sleeve valve adjustments, and single-compartment influent adjustments have always consumed a lot of manpower, resulting in a large workload and high labor costs. With the advancement of smart water management, how to effectively optimize, monitor, and coordinate the secondary sedimentation tank process system has become an important development goal. In addition, compared to the periodic adjustments of manual inspections, the continuous control method of the automatic control system can largely avoid various problems caused by untimely control. In view of the above problems, there is an urgent need to design an intelligent control system and method for secondary sedimentation tanks. Summary of the Invention

[0003] The purpose of this invention is to provide an intelligent control system and method for secondary sedimentation tanks, which solves the technical problems of large workload, high labor costs, relatively slow control, and unfavorable conditions for the construction of intelligent water systems in the existing technology. It can intelligently control the secondary sedimentation tank, greatly reduce the workload of manual inspection and control, reduce labor costs, enhance the timeliness of control, improve the operational stability of the secondary sedimentation tank, and promote the construction of intelligent water systems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] As one aspect of the present invention, an intelligent control system for a secondary sedimentation tank is provided, comprising:

[0006] Data formulation is used to initially determine the setpoints for various control parameters of the secondary sedimentation tank; and / or

[0007] Data collection and judgment: Collect data on control indicators, compare them with the proposed values, and judge the results;

[0008] And / or control content, through the collection and judgment results, to intelligently adjust and control the operation of the secondary sedimentation tank.

[0009] As an example of the above-mentioned intelligent control system for a secondary sedimentation tank, the data setting includes setting values ​​for adjustment time intervals, quantity determination, turbidity of the secondary sedimentation tank effluent, sludge concentration of the sludge discharge weir or sludge discharge sleeve valve, number of external return pumps, liquid level in the forepool of the external return pump, sludge concentration in the external return channel, and operating water volume of the biological tank.

[0010] As an example of the above-mentioned intelligent control system for secondary sedimentation tanks, the system collects and determines the following data: operating signal of external return pump, operating signal of sludge scraper, turbidity of secondary sedimentation effluent, sludge concentration of sludge discharge weir or sludge discharge sleeve valve, liquid level of external return pump forepool, sludge concentration of external return channel, and operating water volume of biological tank.

[0011] As an example of the intelligent control system for a secondary sedimentation tank according to the above aspects of the present invention, the control content includes:

[0012] Sludge discharge weirs or sludge discharge sleeve valves are used to regulate sludge concentration when it is within the normal range or when it is abnormal; and / or

[0013] Effluent turbidity control is used to regulate effluent turbidity when it is within the normal turbidity range and when effluent turbidity is abnormal; and / or

[0014] The sludge scraper malfunction control is used to regulate the inlet gate of the secondary sedimentation tank and automatically adjust the sludge concentration.

[0015] As an intelligent control system for a secondary sedimentation tank according to the above aspects of the present invention, it further includes:

[0016] The concept of quantity-based control involves analyzing the causes of abnormalities in the operation of secondary sedimentation tanks—whether these abnormalities are due to overall or individual factors—and formulating control strategies accordingly; and / or

[0017] The concept of real-time monitoring and interval control is used to monitor the control parameters of the secondary sedimentation tank in real time, and to establish the adjustment cycle based on the data change feedback cycle and the actual on-site operation, so as to carry out interval control.

[0018] As another aspect of the present invention, a method for intelligent control of a secondary sedimentation tank is provided, comprising the following steps:

[0019] S1. Intelligent control of the secondary sedimentation tank according to the main control logic process;

[0020] S2. Intelligent control of the secondary sedimentation tank is performed according to the sub-control logic process.

[0021] As an intelligent control method for a secondary sedimentation tank according to the above aspects of the present invention, S1 includes the following steps:

[0022] S11. Manually input the relevant control parameters for the secondary sedimentation tank;

[0023] S12. Sequentially read the sludge concentration and flow rate of the external return channel, read the sludge scraper operation signal, read the external return pump operation signal, and summarize and judge the inlet gate signal of the single compartment of the secondary sedimentation tank;

[0024] S13. Sequentially determine whether the effluent turbidity is greater than the set value, whether the adjustment interval timer is zero, whether the number of high effluent turbidity chambers divided by the number of operating chambers is greater than the set value, and whether the influent flow rate of the biological tank is greater than the set value.

[0025] S14. Sequentially determine whether the concentration of externally returned sludge is lower than the set range and whether the concentration of externally returned sludge is higher than the concentration range.

[0026] As a method for intelligent control of a secondary sedimentation tank according to the above aspects of the present invention, the summarization and judgment of the inlet gate signal of the single compartment of the secondary sedimentation tank in step S12 includes the following steps:

[0027] S121. Determine whether the signals of the single-compartment inlet gate are all fully open;

[0028] S122. Detect whether there is a signal indicating that the inlet gate of the secondary sedimentation tank is partially closed;

[0029] S123. Determine whether the inlet gate of the secondary sedimentation tank has a fully open signal.

[0030] As a method for intelligent control of a secondary sedimentation tank according to the above aspects of the present invention, S2 includes the following steps:

[0031] S21. Sequentially determine whether there is a fully closed signal at the inlet gate of the secondary sedimentation tank and read the turbidity of the effluent from the secondary sedimentation tank;

[0032] S22. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, whether the liquid level in the forebay of the external return pump is higher than the set range, and whether the external return concentration is higher than the set range.

[0033] S23. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forepool of the external return pump is lower than the set range.

[0034] S24. Sequentially determine whether there is a full-close signal at the inlet gate of the secondary sedimentation tank, whether the concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, and whether the liquid level in the forebay of the external return pump is higher than the set range.

[0035] S25. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forebay of the external return pump is lower than the set range.

[0036] By adopting the above technical solution, the present invention has the following advantages:

[0037] This invention provides an intelligent control system and method for secondary sedimentation tanks. It integrates the inspection of secondary sedimentation tank structures in wastewater treatment plants with biological systems, and studies and organizes relevant information such as problems discovered during inspections and key process parameters. From the perspective of process operation control and optimization, the system intelligently controls the secondary sedimentation tank, enabling corresponding adjustments based on various detection data. This significantly reduces manual workload, lowers labor costs, enhances the timeliness of control, and improves the operational stability of the secondary sedimentation tank, thus promoting the construction of smart water systems. Furthermore, it has been widely applied in actual field operations. Attached Figure Description

[0038] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram illustrating the invention concept of the intelligent control system for secondary sedimentation tanks of this invention;

[0040] Figure 2 This is an architecture diagram of the intelligent control system for the secondary sedimentation tank of the present invention;

[0041] Figure 3 This is a flowchart (upper part) of the intelligent control of the secondary sedimentation tank of the present invention;

[0042] Figure 4 This is a flowchart of the intelligent control of the secondary sedimentation tank of the present invention (lower section). Detailed Implementation

[0043] The technical solution of the present invention will be specifically described below with reference to the accompanying drawings. The detailed features and advantages of the present invention are described in detail in the specific embodiments. The content is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly. Based on the specification, claims and drawings disclosed in this specification, those skilled in the art can easily understand the related objects and advantages of the present invention.

[0044] Figure 1 A schematic diagram illustrating the invention concept of the intelligent control system for secondary sedimentation tanks of the present invention is shown; the specific invention concept of the intelligent control system for secondary sedimentation tanks is as follows: Figure 1 As shown, the operation of the secondary sedimentation tank is mainly regulated and controlled through the following three main and two auxiliary principles.

[0045] The three main concepts include the following: first, regulating the sludge concentration at the sludge discharge weir or sludge discharge sleeve valve; second, regulating the turbidity of the effluent; and third, regulating the operation of the sludge scraper in case of malfunction or shutdown.

[0046] The two auxiliary concepts include the following: first, the concept of quantity-based control; and second, the concept of real-time monitoring and interval-based control.

[0047] The normal operation of the external reflux equipment is crucial to the operation of the secondary sedimentation tank. Therefore, it is necessary to include the pre-judgment of operating conditions in the intelligent system for the secondary sedimentation tank.

[0048] Figure 2 This diagram illustrates the architecture of the intelligent control system for secondary sedimentation tanks according to the present invention; Intelligent control system for secondary sedimentation tanks Figure 2 As shown, this includes data formulation, which is used to initially formulate set values ​​for various control parameters of the secondary sedimentation tank; and / or data collection and judgment, which collects data on control indicators and compares them with the formulated data values ​​to determine the results; and / or control content, which uses the judgment results to intelligently adjust and control the operation of the secondary sedimentation tank.

[0049] The data formulation includes setting values ​​for adjustment time intervals, quantity determination, turbidity of secondary sedimentation tank effluent, sludge concentration of sludge discharge weir or sludge discharge sleeve valve, number of external return pumps, liquid level in the forebay of the external return pump, sludge concentration in the external return channel, and operating water volume of the biological tank.

[0050] The data collection and determination include the operation signals of the external return pump, the operation signal of the sludge scraper, the turbidity of the secondary sedimentation effluent, the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve, the liquid level of the external return pump forepool, the sludge concentration of the external return channel, and the operating water volume of the biological tank.

[0051] The control functions include: sludge concentration control via sludge discharge weir or sludge discharge sleeve valve, used to control sludge concentration within the normal range and when sludge concentration is abnormal; and / or effluent turbidity control, used to control effluent turbidity within the normal range and when effluent turbidity is abnormal; and / or sludge scraper malfunction control, used to control the inlet gate of the secondary sedimentation tank and automatically adjust the sludge concentration.

[0052] Among them, the sludge concentration control of the sludge discharge weir or sludge discharge sleeve valve: The sludge concentration of the sludge discharge weir or sludge discharge sleeve valve directly affects the effluent indicators of the secondary sedimentation tank and the amount of sludge returned to the biological system. Therefore, the control of the sludge discharge weir or sludge discharge sleeve valve is one of the essential control measures for the stable operation of the secondary sedimentation tank.

[0053] Excessive sludge concentration may cause the following effects: excessively high concentration of activated sludge in biological systems increases aeration demand, resulting in energy waste; increased activated sludge volume while influent water quality remains relatively stable leads to a lower food-to-microbe ratio, resulting in insufficient nutrients for microbial growth, poor sludge settling performance, and accelerated sludge aging; gradual accumulation of sludge in the secondary sedimentation tank causes sludge runoff or increases the torque of the sludge scraper, affecting its normal operation, etc.

[0054] Low sludge concentration may cause the following problems: high sludge load in biological systems, resulting in substandard treated water quality; excessively high food-to-microbe ratio, leading to rapid sludge growth and high activity, causing poor sludge settling performance, etc. It is necessary to ensure that the sludge concentration at the sludge discharge weir or sludge discharge sleeve valve is within a stable range for stable operation.

[0055] Analysis of the causes of abnormal mud concentration at the mud discharge weir or mud discharge sleeve valve:

[0056] The high sludge concentration is mainly due to overall factors and individual factors. The overall factor is a high concentration of activated sludge, with each secondary sedimentation tank exhibiting a high concentration. In this case, excess sludge discharge control should be implemented (external recirculation aims to ensure the biological system's sludge load meets normal operating requirements. In actual operation, the calculated sludge load will not be low due to low influent flow, thus preventing insufficient sludge concentration and substandard water quality at normal flow rates. Therefore, reducing the sludge inflow to the secondary sedimentation tank under low flow conditions and correspondingly reducing the external recirculation flow rate is a dynamic equilibrium process to maintain concentration. At this low flow rate, the secondary sedimentation tank...) The phenomenon of high sedimentation compressibility and increased concentration due to excessively long retention time in the tank should be included within the concentration variation range, which is the significance of this patent adopting range control instead of constant concentration control. The individual factor is that the sludge return flow rate of a single compartment is less than the sludge inflow rate. Here, the sludge discharge weir or sleeve valve will be adjusted and controlled by PID according to the current concentration. If the conditions are not met, the sludge inflow rate will be controlled by adjusting the inlet gate of the single compartment secondary sedimentation tank according to the relative proportion. The condition judgment is mainly based on the quantity judgment control concept, the liquid level judgment of the external return pump front tank (fall judgment: overall return flow judgment control optimization) and the overall sludge concentration judgment of the external return channel.

[0057] The reasons for low sludge concentration can be divided into overall factors and individual factors. Overall factors refer to the low concentration in each secondary sedimentation tank. The main reasons for this are low overall activated sludge in the system, high water volume in the biological system leading to high load in the secondary sedimentation tank, and changes in sludge properties resulting in poor settling performance. Here, the conditions are mainly determined by judging the sludge concentration in the external return channel and the influent volume of the biological system to eliminate factors. Individual factors include the sludge return flow rate in a single tank being greater than the sludge inflow rate or the influent volume in a single tank being too large, causing the sludge to be unable to settle effectively. Here, the quantitative judgment control concept, the liquid level in the external return pump forebay, the overall sludge concentration in the external return channel, and the turbidity of the effluent in a single tank are used as judgment conditions and the basis for balance control. PID regulation control is applied to the sludge discharge weir or sleeve valve, and the influent gate of the secondary sedimentation tank in a single tank is adjusted according to a relative proportion to achieve steady-state operation.

[0058] Effluent turbidity control: Effluent turbidity is an important indicator of the effluent quality of the secondary sedimentation tank and plays a key indicative role in the operation and management process. Therefore, when there is a problem with the water quality of the secondary sedimentation tank, in order to ensure the smooth operation of subsequent processes or to ensure that the effluent quality meets the standards when the secondary sedimentation tank is used as the final treatment unit, the control command will have a higher priority than the control command based on the sludge concentration of the sludge discharge weir or sleeve valve.

[0059] Analysis of the causes of abnormal effluent turbidity:

[0060] High effluent turbidity can be mainly attributed to two factors: poor treatment efficiency and poor settling efficiency. Poor water treatment efficiency will inevitably lead to an overall increase in turbidity in the secondary sedimentation tank effluent, rather than just a single compartment. This is caused by the sludge load of the biological system being lower than the current water treatment requirements or abnormal operating indicators of each process section of the biological tank. Therefore, it is necessary to reduce the treated water volume or check the operation of the biological tank. Poor settling efficiency includes both overall and individual factors. Overall factors include the inability of the secondary sedimentation tank to effectively settle due to the large volume of biological treatment water and high load, as well as changes in sludge properties leading to reduced settling performance (severe sludge aging can simultaneously lead to poor treatment efficiency and excessive suspended particulate matter), causing sludge particles to be carried out with the effluent. Individual factors mainly include the amount of sludge returned to a single compartment being less than the amount of sludge fed in, uneven water distribution in a single compartment, or the effluent triangular weir plate not being firmly fixed, causing the weir plate to slip and resulting in sludge loss with the water flow.

[0061] The criteria for determining effluent turbidity include quantity determination and control principles, biological influent volume determination, sludge concentration determination at the sludge discharge weir or sleeve valve, liquid level determination in the forebay of the external return pump, and sludge concentration determination in the external return channel.

[0062] Sludge scraper malfunction control: The main function of the sludge scraper is to scrape the sludge from the sedimentation tank to the sludge hopper collection area. Therefore, if the sludge scraper malfunctions and stops operating, the sludge cannot be effectively collected. To prevent the continuous accumulation of sludge in the secondary sedimentation tank and the direct exceedance of the effluent standard, preventive measures need to be taken in advance. Here, the inlet gate of the corresponding secondary sedimentation tank is closed, which can effectively avoid the problem of continuous sludge accumulation and the problem of effluent exceeding the standard. Closing the inlet gate of the secondary sedimentation tank does not affect the sludge concentration control logic of the sludge discharge weir or sludge discharge sleeve valve, so it can continue to operate until the sludge concentration gradually decreases and the sludge discharge weir or sludge discharge sleeve valve is closed. This operation can reduce the amount of sludge in the sludge hopper of the secondary sedimentation tank, and realize the reduction of the current denitrification sludge and anaerobic sludge in the tank when the secondary sedimentation tank malfunctions and stops operating.

[0063] Quantity-based control principles: Quantity-based control methods include, but are not limited to, specific numbers and percentages of operational data, effectively expressing quantities. Introducing quantity-based control can effectively increase the rationality of judgments and the effectiveness of control. Quantity-based control can be used to analyze the causes of problems: In the process of judging the operation and control of secondary sedimentation tanks, it can be found that the causes of anomalies are often divided into overall factors and individual factors. Therefore, quantity-based control can be used to analyze whether the problem is caused by overall factors or individual factors. Quantity-based control can be used to formulate control strategies: During the control process, we need to organize and further summarize the control command quantities. For example, we can avoid controlling the inflow of water simultaneously, as the water volumes may interfere with each other, resulting in meaningless control.

[0064] Real-time monitoring and interval control principles: To achieve timely control, real-time monitoring is necessary during operation to prevent data changes from going undetected. However, since most control measures in wastewater treatment processes have a lag, data feedback cannot be instantaneous. Therefore, establishing appropriate adjustment cycles based on data change feedback periods and actual on-site operating conditions is essential. This effectively avoids redundant adjustments and over-control caused by lag, both of which ensure system stability. The PID control method used in this intelligent control system for the sludge discharge weir or sludge discharge sleeve valve and the proportional control method for the secondary sedimentation tank inlet gate are only used for single-cycle adjustment measurement optimization; the adjustment time still follows the interval control principle.

[0065] Figure 3 A flowchart illustrating the intelligent control of the secondary sedimentation tank according to the present invention is shown. The relevant equipment and instruments in this invention include the following: an external return channel flow meter, an external return channel sludge concentration meter, an external return pump pre-sink level gauge, a single-compartment secondary sedimentation tank effluent turbidity meter, a single-compartment sludge discharge weir or sludge discharge sleeve valve, an electric sludge discharge weir or sludge discharge sleeve valve, an electric inlet gate for the secondary sedimentation tank, a PID control module, and a PLC programmable logic controller.

[0066] The intelligent control method for secondary sedimentation tanks of the present invention is as follows: Figures 3-4 As shown, it includes the following steps:

[0067] S1. Intelligent control of the secondary sedimentation tank according to the main control logic process;

[0068] S1 includes the following steps:

[0069] S11. Manually input the relevant control parameters for the secondary sedimentation tank, including the following:

[0070] 1. External return pump set operating count, used to determine the current external return pump operating status; 2. Secondary sedimentation tank effluent turbidity set value, used to determine the normal operating status of the secondary sedimentation tank; 3. Tank level adjustment judgment count under high effluent turbidity conditions, used to determine the output control strategy based on the overall effluent water quality status of the secondary sedimentation tank, here a percentage is used as a reference; 4. Adjustment cycle timing interval, used to prevent lag from causing repeated adjustments; 5. Sludge concentration range of sludge discharge weir or sludge discharge sleeve valve, used as the basis for automatic control; 6. Liquid level range of the forebay of the external return pump, used for automatic control judgment.

[0071] 7. External return channel sludge concentration range – used to provide control judgment and early warning based on the overall situation, and to calculate the amount of external return sludge; 8. Biological tank effective volume setting – used to calculate the current sludge concentration of the biological system (can be used as a comparison with the biological system sludge concentration instruments to prevent the undetected deviation of instruments in this system from leading to inaccurate adjustment basis); 9. Biological tank influent flow rate setting – used as the basis for alarm judgment in abnormal situations; 10. Secondary sedimentation tank influent gate opening ratio setting – used for secondary sedimentation tank opening degree control (since the water volume is not linearly related to the gate, it is recommended to adjust according to the current ratio, that is, the larger the current opening, the larger the adjustment range, and the smaller the current opening, the smaller the adjustment range, which can effectively avoid the adjustment being too slow, resulting in a long adjustment cycle, or the adjustment being too fast, resulting in frequent system adjustments).

[0072] S12. Sequentially read the sludge concentration and flow rate of the external return channel, read the sludge scraper operation signal, read the external return pump operation signal, and summarize and judge the inlet gate signal of the single compartment of the secondary sedimentation tank;

[0073] Main control logic flow 1: By externally reading the sludge concentration and flow rate through the external return channel, the current activated sludge concentration of the biological system can be calculated based on the effective volume of the biological system. This concentration can be compared with the sludge concentration meters in the biological system to determine the measurement deviation of the sludge concentration meter and flow meter, ensuring the accuracy of subsequent control reference data. After completion, the process transitions to main control logic flow 2.

[0074] Main control logic flow 2: Read the sludge scraper operation signal. If the sludge scraper stops during operation, determine whether the inlet gate has a closure signal. If there is no closure signal, close the inlet gate of the secondary sedimentation tank single compartment to prevent the sludge from being unable to reach the sludge hopper due to the sludge scraper stopping, which would cause continuous sludge intake and sludge accumulation. After the sludge scraper operation and the inlet gate signal are found to be in good condition, proceed to main control logic flow 3.

[0075] Main control logic flow 3: Read the external return pump operation signal and compare it with the set number of external return pumps. If the number is less than the set number, an external return pump has unexpectedly stopped. The external return pump is a key operating device for the secondary sedimentation tank and the entire biological system. If it cannot meet the operating requirements, any adjustments are meaningless to help regulate the normal operation of the secondary sedimentation tank. Therefore, it must be handled promptly. This system will maintain its original state without adjustment, issue a low external return pump operation alarm, and can optionally integrate the current external return pump fault signals, outputting detailed equipment alarm signal content. After the external return pump meets the operating requirements, proceed to main control logic flow 4.

[0076] Main control logic flow 4: Summarize the signals from the single-compartment inlet gate of the secondary sedimentation tank, determine whether there is an adjustment signal for the inlet gate of the secondary sedimentation tank, and if there is an adjustment signal, read the opening degree of the inlet gate of the secondary sedimentation tank and proceed to main control logic flow 5; if there is no adjustment signal, proceed to main control logic flow 8.

[0077] S121. Main control logic flow 5: Determine whether all single-compartment inlet gate signals are open. If all single-compartment inlet gate signals are open, it means that the sludge concentration of all sludge discharge weirs or sludge discharge sleeve valves is low and cannot be adjusted according to the liquid level of the external return forepool. Read the inlet water volume of the biological tank and determine whether it is greater than the set water volume. If it is greater than the set water volume, it means that the secondary sedimentation tank system is overloaded under the current water volume, making it difficult for sludge to settle. Conversely, it means that the overall concentration of activated sludge in the biological system is low or the sludge properties have changed, resulting in poor settling performance. This causes the amount of sludge in the secondary sedimentation tank to be too small, resulting in poor compression and sedimentation effect or poor sludge settling performance, resulting in ineffective settling. At this time, output the corresponding alarm according to the current situation. If not all single-compartment inlet gate signals are open, then proceed to main control logic flow 6.

[0078] S122. Main control logic flow 6: Detect whether there is a signal to close the secondary sedimentation tank inlet gate: If there is a signal to close the secondary sedimentation tank inlet gate, close the secondary sedimentation tank inlet gate according to the current ratio. There are two points to note here: First, since the overall water volume does not change after the inlet gate in the system is closed, the water volume in other secondary sedimentation tanks will increase. Therefore, the tank with the signal to open the gate will no longer open the gate. Second, the signal to close the gate has been avoided in the judgment of this system. There is no need to worry about the accumulation of water in the secondary sedimentation tank. If there is no signal to close the gate, proceed to the main control logic flow 7.

[0079] S123. Main Control Logic Flow 7: Determine if there is a full opening signal for the secondary sedimentation tank inlet gate: If there is no full opening signal, proportionally increase the gate opening of the required chamber; if there is a full opening signal, proportionally decrease the gate opening of the chamber without a full opening signal. At this point, the adjustment process for the secondary sedimentation tank inlet gate and related early warning and alarm output logic are complete. Because all opening and closing signals are determined by the single-chamber program and then output to the main program for single-time control, and the single-chamber program determination in this system is controlled by the adjustment cycle interval, even if the adjustment is completed within the same adjustment cycle and the inlet gate adjustment signal is cleared before entering main control logic flow 8, there will still be a lag in adjustment waiting due to the adjustment cycle not being reached, and there is no repeated adjustment.

[0080] S13.: Sequentially check whether the effluent turbidity is greater than the set value, whether the adjustment interval timer is zero, whether the number of high effluent turbidity chambers divided by the number of operating chambers is greater than the set value, and whether the influent flow rate of the biological tank is greater than the set value.

[0081] Main control logic flow 8: Detect whether there is a high turbidity signal in the effluent. If there is a high turbidity signal in the effluent, proceed to the main control logic flow 9. If not, proceed to the sub-control logic flow 21.

[0082] Main control logic flow 9: Determine whether the adjustment interval timer has returned to zero. If the adjustment time has not been reached, end the operation and return to main control logic flow 1 for re-determination. In the adjustable state, read the number of secondary sedimentation tanks in operation. Use the inlet gate of the secondary sedimentation tank without foot signal chamber as the operation signal. After reading, transfer to main control logic flow 10.

[0083] Main control logic flow 10: Determine if the number of high turbidity chambers divided by the number of operating chambers is greater than the set value. If it is less than or equal to the set value, proceed to sub-control logic flow 28; if it is greater than the set value, proceed to main control logic flow 11. When most chambers in the secondary sedimentation tank simultaneously experience water quality problems, the possible causes include only the following: First, the biological tank is overloaded, leading to poor biological treatment effect and increased turbidity, or the secondary sedimentation tank has a high water load; Second, there is no abnormal water volume problem, but the overall water quality treatment fails to meet standards due to excessively low activated sludge concentration in the biological system; Third, the biological tank concentration is too high, causing the amount of sludge entering the secondary sedimentation tank to exceed the amount of sludge returned from external circulation, resulting in a general increase in turbidity in the secondary sedimentation tank; Fourth, problems with the biological section control result in unsatisfactory water quality treatment effect, or changes in the properties of activated sludge make it difficult for sludge to settle effectively.

[0084] Main control logic flow 11: Determine whether the influent flow to the biological tank is greater than the set value. If it is greater than the set value, issue an overload warning for the current water volume. Otherwise, proceed to main control logic flow 12.

[0085] S14. Sequentially determine whether the concentration of externally returned sludge is lower than the set range and whether the concentration of externally returned sludge is higher than the concentration range.

[0086] Main control logic flow 12: Determine whether the concentration of the external return sludge is lower than the set range. If it is lower than the set range, it means that the concentration of activated sludge in the biological system is low and the water quality treatment does not meet the requirements. Output a warning that the current activated sludge concentration is too low. If it is not lower than the set range, proceed to main control logic flow 13.

[0087] Main control logic flow 13: Determine if the concentration of the externally returned sludge is higher than the set range. If it is, the current high turbidity in the multi-compartment effluent is due to excessively high sludge concentration causing sludge accumulation in the secondary sedimentation tank. An alert for excessively high activated sludge concentration is issued, and discharge of excess sludge is recommended. If the concentration is not higher than the set range, as previously determined, the current externally returned sludge concentration is within the set range. Under conditions where the water volume is not overloaded, the problem is likely due to issues with biological treatment adjustments, substandard water quality, or problems with the properties of the activated sludge causing ineffective settling. In this case, an alert for checking the biological treatment operation and activated sludge properties is issued. This concludes the high turbidity judgment for the effluent from the multi-compartment secondary sedimentation tank.

[0088] S2. Intelligent control of the secondary sedimentation tank is performed according to the sub-control logic process.

[0089] S2 includes the following specific steps:

[0090] S21. Sequentially determine whether there is a fully closed signal at the inlet gate of the secondary sedimentation tank and read the turbidity of the effluent from the secondary sedimentation tank;

[0091] Sub-control logic flow 21: Determine if the secondary sedimentation tank inlet gate has a closed signal: If the secondary sedimentation tank inlet gate has a closed signal, an alarm for stopping operation of the corresponding secondary sedimentation tank is output. It should be noted that this alarm is only for monitoring the operation status of the operators and does not affect the subsequent normal control of the sludge concentration at the sludge discharge weir. At this time, if the scraper is damaged, the inlet gate status has already been closed in the main control flow. If the sludge concentration at the sludge discharge weir or sludge discharge sleeve valve is adjusted to the point where it cannot be adjusted further, the issued inlet gate opening signal will still be overridden by the main control program's closing command through normal operation of the process. There will be no issue of the scraper malfunction triggering the opening of the secondary sedimentation tank inlet gate, causing effluent water quality problems. Therefore, regardless of whether a closed signal exists, the detection of the secondary sedimentation tank inlet gate closed signal will jump to sub-control logic flow 22.

[0092] Sub-control logic flow 22: Read the turbidity of the secondary sedimentation tank effluent: If the turbidity of the secondary sedimentation tank effluent is greater than the set value, a high turbidity warning signal is issued, and the process jumps to the main control logic flow 8. The main control program first performs an overall turbidity judgment. As can be seen from the previous flow, the turbidity monitoring here does not participate in the adjustment cycle time interval limitation. Therefore, the turbidity of the secondary sedimentation tank effluent can be effectively monitored in real time. If the turbidity of the secondary sedimentation tank effluent is less than or equal to the set value, it is determined whether the adjustment interval timer has been reached and whether it has been reset to zero. If the adjustment interval has not been reached, no operation is performed, and the process jumps to the main control logic flow 1. If the adjustment interval has been reached, the process jumps to the sub-control logic flow 23.

[0093] S22. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, whether the liquid level in the forebay of the external return pump is higher than the set range, and whether the external return concentration is higher than the set range.

[0094] Sub-control logic flow 23: Determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range. If it is higher than the set range, jump to sub-control logic flow 24. If it is not higher than the set range, jump to sub-control logic flow 26.

[0095] Sub-control logic flow 24: Determine whether the liquid level in the forebay of the external return pump is greater than the set range. If it is not greater than the set range, it means that there is room for adjustment of the current sludge discharge weir or sleeve valve. At this time, PID mode control can be performed according to the concentration. If it is greater than the set range, it means that although the concentration of the sludge discharge weir or sludge discharge sleeve valve is high, there is no room for adjustment according to the liquid level control. Jump to sub-control logic flow 25.

[0096] Sub-control logic flow 25: Determine if the external return concentration is greater than the set range. If it is greater than the set range, it means that the overall sludge concentration of the secondary sedimentation tank is too high and the output activated sludge concentration is too high. It is recommended to issue a sludge discharge warning. In this case, since the effluent quality is not affected, this problem can be temporarily solved by increasing the external return flow rate. However, firstly, this causes the sludge concentration of the biological system to rise rapidly, leading to an imbalance in the food-to-microbe ratio. Secondly, after adding the external return flow, the secondary sedimentation tank will be in a high external return flow state for a long time. If the equipment fails and there is no backup, the secondary sedimentation tank system will collapse directly. Therefore, this operation is not recommended. If the external return concentration is not greater than the set range, wait for other single compartments to adjust, do not perform any operation, and return to the main control logic flow 1 to run again. It's worth mentioning that no operation is performed here because the initial judgment condition is that the effluent quality is fine, so no operation can be performed temporarily. If the sludge discharge weir or sleeve valve is closed slightly during the operation of other compartments, the liquid level in the forepool of the external return pump will drop, thus freeing up operating space. If the concentration in other compartments does not need to be adjusted or needs to be increased, then the sludge concentration in other compartments is higher than the set range. At this time, the external return sludge concentration will inevitably gradually exceed the set range, and the external return concentration will be judged to be higher than the set range.

[0097] S23. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forepool of the external return pump is lower than the set range.

[0098] Sub-control logic flow 26: Determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range. If it is within the set range, the system will operate normally without any operation and will jump to the main control logic flow 1 to run again. If the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, then jump to the sub-control logic flow 27.

[0099] Sub-control logic flow 27: Is the liquid level in the forebay of the external return pump lower than the set range? If it is not lower than the set range, there is room for the sludge discharge weir or sludge discharge sleeve valve to close. At this time, the sludge discharge weir or sludge discharge sleeve valve is controlled by PID mode to close. If it is lower than the set range, it indicates that the following situations exist: First, uneven water inflow into the secondary sedimentation tank leads to uneven sludge concentration in the secondary sedimentation tank, with lower sludge concentration in the compartments with less water. Second, too much water or poor sludge settling performance leads to ineffective sludge settling in the secondary sedimentation tank. Third, the overall sludge concentration is too low, resulting in an overall low amount of sludge in the secondary sedimentation tank. Therefore, at this time, a signal to open the secondary sedimentation tank inlet gate is issued, and the process is transferred to main control logic flow 4 for judgment and processing.

[0100] S24. Sequentially determine whether there is a full-close signal at the inlet gate of the secondary sedimentation tank, whether the concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, and whether the liquid level in the forebay of the external return pump is higher than the set range.

[0101] Sub-control logic flow 28: Determine whether there is a closing signal at the inlet gate of the secondary sedimentation tank. This function is the same as sub-control logic flow 21, so it will not be described in detail. After the signal detection is completed, it will be transferred to sub-control logic flow 29.

[0102] Sub-control logic flow 29: Determine whether the concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range. If it is higher than the set range, proceed to sub-control logic flow 30. If it is not higher than the set range, proceed to sub-control logic flow 31.

[0103] Sub-control logic flow 30: Determine if the liquid level in the forebay of the external return pump is greater than the set range. If it is not greater than the set range, there is room for adjustment, and the sludge discharge weir or sludge discharge sleeve valve is closed in PID mode. If it is greater than the set range, there is no room for closing the sludge discharge weir or sludge discharge sleeve valve. The reason for this situation is that the sludge concentration is high or the water volume is large, which causes the sludge to be unable to settle in time, resulting in an increase in effluent turbidity. Such phenomena as water quality problems and sludge aging have been eliminated by the number of high turbidity compartments in the pre-test. Therefore, a signal to close the secondary sedimentation tank inlet gate is issued, and the process is transferred to the main control logic flow 4 to summarize and judge the inlet gate adjustment command. After the judgment, a high water load prompt or a secondary sedimentation tank gate closure operation will be performed. Since the pre-judgment condition for issuing the command has been judged by the number of high turbidity compartments, the phenomenon of too many secondary sedimentation tank inlet gate closure commands will not be issued.

[0104] S25. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forebay of the external return pump is lower than the set range.

[0105] Sub-control logic flow 31: Determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range. If it is within the set range, the sludge discharge weir or sludge discharge sleeve valve is not adjustable, indicating a settling problem due to water volume. Therefore, a signal to close the secondary sedimentation tank inlet gate is issued, and the process is transferred to main control logic flow 4 for summarizing and judging the inlet gate adjustment command. If the concentration is lower than the set range, the process is transferred to sub-control logic flow 32.

[0106] Sub-control logic flow 32: Determine whether the liquid level in the forebay of the external return pump is less than the set range. If it is not less than the set range, the sludge discharge weir or sludge discharge sleeve valve has room to close. Perform PID mode closing operation on the sludge discharge weir or sludge discharge sleeve valve. If it is less than the set range, issue a closing signal for the secondary sedimentation tank inlet gate and transfer to the main control logic flow 4 to summarize and judge the inlet gate adjustment command.

[0107] At this point, the main control logic flow and sub-control logic flow of this system have been completed and a closed loop has been formed.

[0108] Finally, it should be noted that although the present invention has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Various equivalent changes or substitutions can be made without departing from the concept of the present invention. Therefore, any changes or modifications to the above embodiments within the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. An intelligent control system for a secondary sedimentation tank, characterized in that, include: Data formulation is used to initially formulate set values ​​for various control parameters of the secondary sedimentation tank. The data formulation includes set values ​​for adjustment time intervals, quantity determination, turbidity of the secondary sedimentation tank effluent, sludge concentration of the sludge discharge weir or sludge discharge sleeve valve, number of external return pumps, liquid level in the forepool of the external return pumps, sludge concentration in the external return channel, and operating water volume of the biological tank. The data collection and judgment process involves collecting data on control indicators and comparing them with predetermined values ​​to determine the results. The data collection and judgment process includes the operation signal of the external return pump, the operation signal of the sludge scraper, the turbidity of the secondary sedimentation effluent, the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve, the liquid level of the external return pump forepool, the sludge concentration of the external return channel, and the operating water volume of the biological tank. The control measures involve intelligently regulating and managing the operation of the secondary sedimentation tank based on the collected judgment results. These control measures include: The sludge discharge weir or sludge discharge sleeve valve is used to regulate the sludge concentration when it is within the normal range and when the sludge concentration is abnormal. Effluent turbidity control is used to regulate effluent turbidity when it is within the normal turbidity range and when effluent turbidity is abnormal. The sludge scraper malfunction control system is used to regulate the inlet gate of the secondary sedimentation tank and automatically adjust the sludge concentration. Also includes: The concept of quantity-based control involves analyzing whether the abnormal operation of the secondary sedimentation tank is caused by overall or individual factors, and then formulating control strategies accordingly. The concept of real-time monitoring and interval control is used to monitor the control parameters of the secondary sedimentation tank in real time, and to establish the adjustment cycle based on the data change feedback cycle and the actual on-site operation, so as to carry out interval control.

2. A method for intelligent control of a secondary sedimentation tank in the intelligent control system for a secondary sedimentation tank as described in claim 1, characterized in that, Includes the following steps: S1. Intelligent control of the secondary sedimentation tank is performed according to the main control logic flow, specifically including the following steps: S11. Manually input the relevant control parameters for the secondary sedimentation tank; S12. Sequentially read the sludge concentration and flow rate of the external return channel, read the sludge scraper operation signal, read the external return pump operation signal, and summarize and judge the inlet gate signal of the single compartment of the secondary sedimentation tank; S13. Sequentially determine whether the effluent turbidity is greater than the set value, whether the adjustment interval timer is zero, whether the number of high effluent turbidity chambers divided by the number of operating chambers is greater than the set value, and whether the influent flow rate of the biological tank is greater than the set value. S14. Sequentially determine whether the concentration of externally returned sludge is lower than the set range and whether the concentration of externally returned sludge is higher than the concentration range; S2. Intelligent control of the secondary sedimentation tank is performed according to the sub-control logic flow, specifically including the following steps: S21. Sequentially determine whether there is a fully closed signal at the inlet gate of the secondary sedimentation tank and read the turbidity of the effluent from the secondary sedimentation tank; S22. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, whether the liquid level in the forebay of the external return pump is higher than the set range, and whether the external return concentration is higher than the set range. S23. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forepool of the external return pump is lower than the set range. S24. Sequentially determine whether there is a full-close signal at the inlet gate of the secondary sedimentation tank, whether the concentration of the sludge discharge weir or sludge discharge sleeve valve is higher than the set range, and whether the liquid level in the forebay of the external return pump is higher than the set range. S25. Sequentially determine whether the sludge concentration of the sludge discharge weir or sludge discharge sleeve valve is lower than the set range, and whether the liquid level in the forebay of the external return pump is lower than the set range.

3. The intelligent control method for a secondary sedimentation tank as described in claim 2, characterized in that, The signal aggregation and judgment of the single-compartment inlet gate of the secondary sedimentation tank in S12 includes the following steps: S121. Determine whether the signals of the single-compartment inlet gate are all fully open; S122. Detect whether there is a signal indicating that the inlet gate of the secondary sedimentation tank is partially closed; S123. Determine whether the inlet gate of the secondary sedimentation tank has a fully open signal.

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