Sewage plant external return sludge measurement and control system based on ultrasonic cross-correlation method

Abstract

The invention relates to the technical field of sludge treatment, and discloses a sewage plant external reflux sludge measurement and control system based on an ultrasonic cross-correlation method, and the system comprises an acquisition module which is used for obtaining the sludge parameters of a sludge external reflux channel and the water inlet flow of a biochemical pool; the opening degree initial setting module is used for calculating the current sludge reflux ratio according to the sludge flow and the water inlet flow of the biochemical pool; controlling the opening degree of a sludge external reflux pump to obtain an initial opening degree; the opening degree adjusting module is used for adjusting the current opening degree of the sludge external reflux pump according to the sludge concentration change conditions of a plurality of time periods after the current time period; and the fault early warning module is used for carrying out pipeline blockage early warning according to the sludge flow and the residual sludge pump well parameters. According to the invention, a complete external return sludge measurement-decision-control closed-loop system is constructed, and the problems of dependence on experience setting, adjustment lag and insufficient control precision in the external return sludge control process of the existing sewage plant are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of sludge treatment technology, and more specifically, to a monitoring and control system for wastewater treatment plant external return sludge based on ultrasonic cross-correlation method. Background Technology

[0002] In wastewater treatment, the operational performance of the activated sludge system directly impacts effluent quality and wastewater treatment efficiency. External sludge return is a common control method in activated sludge systems. By returning a portion of the sludge from the biological treatment tank to the influent area, the concentration of microorganisms in the biological treatment tank can be maintained, the reaction effect can be ensured, and the system load can be regulated. However, existing wastewater treatment plants face numerous problems in controlling external sludge return.

[0003] Traditional control methods often rely on experience-based settings or manual adjustments, maintaining sludge return flow by manually controlling the opening or stopping of the return pump. This approach suffers from significant lag, untimely adjustments, and insufficient precision, making it difficult to meet the demands for refined control of sludge return flow. For example, when influent flow or sludge concentration fluctuates significantly, manual or experience-based control can easily lead to insufficient or excessive external sludge return, resulting in abnormal microbial concentrations in the biochemical tank, decreased treatment efficiency, and even system instability. Furthermore, existing wastewater treatment plants often use a single parameter as the basis for control, such as relying solely on sludge pump opening or sludge flow rate, neglecting the coupling relationship between key operating indicators such as sludge concentration and influent flow rate. This leads to low control precision, delayed system response, and difficulty in achieving continuous, dynamic, and intelligent regulation.

[0004] Therefore, it is necessary to provide a wastewater treatment plant external sludge return monitoring and control system based on ultrasonic cross-correlation method to solve the problems of traditional control methods that rely on manual experience to adjust sludge return flow, which have problems such as strong lag, untimely adjustment, and insufficient accuracy, and the use of a single control parameter can easily lead to system instability. Summary of the Invention

[0005] In view of this, the present invention proposes a wastewater treatment plant external sludge return monitoring and control system based on ultrasonic cross-correlation method, which aims to solve the problems of traditional control methods that rely on manual experience to adjust sludge return flow, resulting in strong lag, untimely adjustment, and insufficient accuracy, and the instability of system operation due to the use of a single control parameter.

[0006] This invention proposes a monitoring and control system for wastewater treatment plant external return sludge based on ultrasonic cross-correlation method, comprising: The data acquisition module is used to acquire sludge parameters and influent flow rate of the biological treatment tank from the sludge external return channel; wherein, the sludge parameters include sludge flow rate and sludge concentration; The initial opening module is used to calculate the current sludge return ratio based on the sludge flow rate and the influent flow rate of the biological treatment tank; compare the current sludge return ratio with the target return ratio to control the opening of the sludge external return pump and obtain the initial opening. The opening adjustment module is used to determine whether to adjust the initial opening of the sludge external return pump based on the sludge concentration in the current time period. If it is determined that adjustment is needed, the initial opening of the sludge external return pump is adjusted according to the sludge concentration in the current time period, and the opening of the sludge external return pump is adjusted according to the sludge concentration changes in the following time periods. The fault early warning module is used to provide early warning of pipeline blockage based on sludge flow rate and residual sludge pump well parameters.

[0007] Furthermore, the initial opening determination module, when calculating the current sludge return ratio based on the sludge flow rate and the influent flow rate of the biological treatment tank, includes: Obtain the average sludge flow rate within a set time window, and the average influent flow rate of the biological treatment tank within the same time window. The current sludge return ratio is the ratio of the average sludge flow rate to the average influent flow rate.

[0008] Furthermore, the initial opening module is used to compare the current sludge return ratio with the target return ratio to control the opening of the sludge external return pump. When obtaining the initial opening, it includes: Set the opening degree of the sludge external return pump to 50%. Calculate the difference between the current sludge return ratio and the target return ratio; If the ratio difference is within the error range, the opening of the sludge external return pump will not be initially corrected, and 50% of the opening will be used as the initial opening. If the ratio difference is not within the error range, the opening of the sludge external return pump will be initially corrected to make the ratio difference within the error range, and the initially corrected opening will be used as the initial opening. The initial opening is at most 100% and at least zero.

[0009] Furthermore, when the opening adjustment module determines whether to adjust the initial opening of the sludge external return pump based on the sludge concentration in the current time period, it includes: Within the current time period, several data collection time points are set to obtain the sludge concentration at each data collection time point and calculate the average sludge concentration. The average sludge concentration is compared with a preset concentration range. If the average sludge concentration is within the preset concentration range, it is determined that the initial opening degree will not be adjusted. If the average sludge concentration is not within the preset concentration range, then it is determined that the initial opening degree should be adjusted.

[0010] Furthermore, when the opening adjustment module adjusts the initial opening of the sludge external return pump according to the sludge concentration in the current time period, it includes: If the average sludge concentration is greater than the maximum value of the preset concentration range, the difference between the average sludge concentration and the maximum value of the preset concentration range is calculated and recorded as the first difference. The initial opening is then adjusted by reducing the value based on the first difference. A first range is set. If the first difference is less than the minimum value of the first range, the initial opening is adjusted by a first adjustment coefficient. If the first difference is within the first range, the initial opening is adjusted by a second adjustment coefficient. If the first difference is greater than the maximum value of the first range, the initial opening is adjusted by a third adjustment coefficient. The adjustment coefficient ranges from 1 to 0.5, where the adjusted opening is the product of the initial opening and the adjustment coefficient.

[0011] Furthermore, when the opening adjustment module is used to adjust the initial opening of the sludge external return pump according to the sludge concentration in the current period, it also includes: If the average sludge concentration is less than the minimum value of the preset concentration range, the difference between the minimum value of the preset concentration range and the average sludge concentration is calculated and recorded as the second difference. The initial opening is then adjusted by increasing the opening based on the second difference. Specifically, a second range is set. If the second difference is less than the minimum value of the second range, the initial opening is adjusted using a fourth adjustment coefficient. If the second difference is within the second range, the initial opening is adjusted using a fifth adjustment coefficient. If the second difference is greater than the maximum value of the second range, the initial opening is adjusted using a sixth adjustment coefficient. The adjustment coefficient ranges from 1 to the fourth adjustment coefficient, which is less than the fifth adjustment coefficient, which is less than the sixth adjustment coefficient, which is less than 1.5. The adjusted opening is the product of the initial opening and the adjustment coefficient, and the maximum adjusted opening is 100%.

[0012] Furthermore, when the opening adjustment module readjusts the opening of the sludge external return pump based on the changes in sludge concentration over several subsequent time periods, it includes: Obtain the average sludge concentration for each time period within a number of time periods, and calculate the mean difference between adjacent average sludge concentrations. If all mean differences are within the preset difference range, the current opening degree of the sludge external return pump will not be adjusted again; otherwise, it is determined that the current opening degree of the sludge external return pump will be adjusted again.

[0013] Furthermore, when the opening adjustment module is used to readjust the opening of the sludge external return pump based on the changes in sludge concentration over several subsequent time periods, it also includes: Calculate the difference between the average sludge concentration of the last time period and the current time period among several time periods, and record it as the third difference; If the third difference is zero, it is determined that the current opening of the sludge external return pump will not be adjusted again. If the third difference is greater than zero, the opening degree of the current sludge external return pump is increased; if the third difference is less than zero, the opening degree of the current sludge external return pump is decreased.

[0014] Furthermore, if the third difference is greater than zero, the opening degree of the current sludge external return pump is increased; if the third difference is less than zero, the opening degree of the current sludge external return pump is decreased, including: When the third difference is greater than zero, a first difference threshold is set. If the third difference is less than the first difference threshold and greater than zero, the opening of the sludge external return pump is increased by a first adjustment coefficient. If the third difference is greater than or equal to the first difference threshold, the opening of the sludge external return pump is increased by a second adjustment coefficient. The adjustment coefficient ranges from 1.5 to 1.5. When the third difference is less than zero, a second difference threshold is set. If the third difference is greater than the second difference threshold but less than zero, the opening of the sludge external return pump is reduced using a third adjustment coefficient. If the third difference is less than or equal to the second difference threshold, the opening of the sludge external return pump is reduced using a fourth adjustment coefficient. The adjustment coefficient ranges from 1 to the third adjustment coefficient to the fourth adjustment coefficient to 0.5. The adjusted opening degree is the product of the adjustment coefficient and the current opening degree of the sludge external return pump; wherein, the maximum opening degree after the adjustment is 100%.

[0015] Furthermore, when the fault early warning module is used to provide early warning of pipeline blockage based on sludge flow rate and residual sludge pump well parameters, it includes: If the sludge flow rate is consistently lower than the preset minimum flow rate for a preset duration, and the sludge depth in the sludge pump well is greater than the preset minimum depth, then it is preliminarily determined that the pipeline is blocked. Once a preliminary diagnosis of pipe blockage is made, the opening of the sludge external return pump is increased to the maximum opening, and the sludge flow rate is continuously monitored. If the sludge flow rate remains unchanged or decreases within a set time, the pipe is determined to be blocked, and a pipe blockage warning is issued.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: By collaboratively collecting and comprehensively analyzing key operating parameters such as sludge flow rate, sludge concentration, and influent flow rate of the biological treatment tank, this invention constructs a complete closed-loop system for external sludge return measurement, decision-making, and control, effectively solving the problems of reliance on experience-based settings, adjustment lag, and insufficient control precision in the control of external sludge return in existing wastewater treatment plants. Firstly, this invention uses an acquisition module to monitor the sludge flow state in the external sludge return channel online using the ultrasonic cross-correlation method. This allows for the simultaneous acquisition of high-precision sludge flow rate and sludge concentration data without contact with the fluid or electromagnetic interference, providing a reliable data foundation for subsequent control. Secondly, the initial opening determination module uses the sludge return ratio as the core control indicator, calculating and comparing the real-time measured sludge flow rate with the influent flow rate of the biological treatment tank. This controls the external sludge return from the perspective of the overall system load, avoiding the problems of insufficient or excessive return caused by controlling based on only a single parameter. Furthermore, the sludge opening adjustment module introduces a multi-period dynamic adjustment mechanism based on sludge concentration. This mechanism not only corrects the initial opening of the external return pump based on the current sludge concentration but also adjusts the pump opening secondary or multiple times based on the sludge concentration trends over subsequent periods. This achieves more stable, continuous, and precise sludge return control, effectively reducing sludge concentration fluctuations in the biological treatment tank and improving system operational stability. In addition, the fault early warning module, through comprehensive analysis of sludge flow rate and residual sludge pump well operating parameters, provides early warnings of abnormal operating conditions such as pipeline blockage, avoiding system operational risks caused by sludge transport obstructions. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a functional block diagram of a wastewater treatment plant external return sludge monitoring and control system based on ultrasonic cross-correlation method, provided in an embodiment of the present invention. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] In some embodiments of this application, see Figure 1 As shown, this embodiment provides a wastewater treatment plant external return sludge monitoring and control system based on ultrasonic cross-correlation method, including: The data acquisition module is used to acquire sludge parameters and influent flow rate of the biological treatment tank from the sludge external return channel; wherein, the sludge parameters include sludge flow rate and sludge concentration; The initial opening module is used to calculate the current sludge return ratio based on the sludge flow rate and the influent flow rate of the biological treatment tank; compare the current sludge return ratio with the target return ratio to control the opening of the sludge external return pump and obtain the initial opening. The opening adjustment module is used to determine whether to adjust the initial opening of the sludge external return pump based on the sludge concentration in the current time period. If it is determined that adjustment is needed, the initial opening of the sludge external return pump is adjusted according to the sludge concentration in the current time period, and the opening of the sludge external return pump is adjusted according to the sludge concentration changes in the following time periods. The fault early warning module is used to provide early warning of pipeline blockage based on sludge flow rate and residual sludge pump well parameters.

[0020] It is understandable that this invention constructs a complete closed-loop system for external sludge return measurement, decision-making, and control by collaboratively collecting and comprehensively analyzing key operating parameters such as sludge flow rate, sludge concentration, and influent flow rate of the biological treatment tank. This effectively solves the problems of relying on experience-based settings, adjustment lag, and insufficient control precision in the existing external sludge return control process of sewage treatment plants.

[0021] Specifically, firstly, this invention utilizes an ultrasonic cross-correlation method in the acquisition module to monitor the sludge flow state within the external sludge return channel online. This allows for the simultaneous acquisition of high-precision sludge flow rate and concentration data without contact with the fluid or electromagnetic interference, providing a reliable data foundation for subsequent control. Secondly, the initial opening module uses the sludge return ratio as the core control indicator. It calculates and compares the real-time measured sludge flow rate with the influent flow rate of the biological treatment tank, controlling the externally returned sludge from the perspective of the overall system load. This avoids the problems of insufficient or excessive return caused by controlling based on a single parameter. Furthermore, the opening adjustment module introduces a multi-period dynamic adjustment mechanism based on sludge concentration. It can not only correct the initial opening of the external return pump based on the current sludge concentration but also adjust the pump opening secondary or multiple times based on the sludge concentration change trend over several subsequent periods. This achieves more stable, continuous, and precise sludge return control, effectively reducing sludge concentration fluctuations in the biological treatment tank and improving system operational stability. In addition, the fault early warning module can provide early warning of abnormal conditions such as pipeline blockage by comprehensively analyzing the sludge flow rate and the operating parameters of the residual sludge pump well, thus avoiding system operation risks caused by sludge transportation obstruction.

[0022] Furthermore, this application focuses on sludge monitoring and control based on the online monitoring device and method for the concentration and flow rate of channel-type external sludge in wastewater treatment plants, as described in application number 202311649028.3. Specifically, an ultrasonic sensor employs a high-frequency continuous pulse ultrasonic cross-correlation measurement method to perform stratified scanning of suspended particles within the external sludge return channel, acquiring real-time sludge flow rate and concentration data, and transmitting the measurement results to the acquisition module. Simultaneously, the influent flow rate of the biological treatment tank is obtained by a flow meter installed at the influent pipe or channel. The central control system calculates the current sludge return ratio based on the acquired parameters, and the start / stop control module generates an initial opening control command for the external sludge return pump. Subsequently, the opening adjustment module dynamically corrects the opening of the external sludge return pump based on real-time and historical sludge concentration changes, thereby achieving refined control of the amount and concentration of externally returned sludge. When abnormal changes in sludge flow rate or abnormalities in the residual sludge pump well level or operating parameters are detected, the fault early warning module triggers a blockage early warning message and uploads it to the central control room, prompting maintenance personnel to handle the situation promptly.

[0023] In some embodiments of this application, the initial opening determination module is used to calculate the current sludge return ratio based on the sludge flow rate and the influent flow rate of the biological treatment tank, including: Obtain the average sludge flow rate within a set time window, and the average influent flow rate of the biological treatment tank within the same time window. The current sludge return ratio is the ratio of the average sludge flow rate to the average influent flow rate.

[0024] Understandably, calculating the current sludge return ratio using the average sludge flow rate and the average influent flow rate within a set time window, compared to calculations based on instantaneous sampling values, effectively suppresses random errors caused by hydraulic fluctuations, pump start-up and shutdown, bubble disturbances, and instantaneous noise from ultrasonic measurements during sludge external return, thus improving the stability and reliability of the sludge return ratio calculation results. Smoothing the data using the time window average method avoids frequent triggering of external return pump opening adjustments or start-up / shutdown controls due to abnormal instantaneous flow fluctuations, thereby reducing mechanical wear and increased energy consumption caused by frequent equipment operation. Simultaneously, this method more realistically reflects the actual operating conditions of the wastewater treatment plant over a period of time, making the sludge return ratio calculation results more representative and facilitating subsequent control module decision-making based on the overall load level. Furthermore, the length of the time window can be flexibly set according to the wastewater treatment plant's scale, process characteristics, and operational stability, balancing response speed and control accuracy, further enhancing the adaptability and engineering practicality of the external return sludge control system.

[0025] In one specific embodiment, a time window is set to 5 minutes. Within this time window, the acquisition module continuously acquires sludge flow data in the sludge external return channel at a fixed sampling period, and performs statistical processing on the acquired sludge flow data to calculate the average sludge flow within the 5 minutes. Simultaneously, within the same 5-minute time window, the influent flow meter of the biological treatment tank acquires influent flow data and calculates the corresponding average influent flow. Subsequently, the initial opening determination module calculates the ratio between the average sludge flow and the average influent flow to obtain the sludge return ratio for the current period, and uses this sludge return ratio as the basis for the initial control of the external return pump opening.

[0026] In some embodiments of this application, the initial opening module is used to compare the current sludge return ratio with the target return ratio to control the opening of the sludge external return pump. When obtaining the initial opening, the module includes: Set the opening degree of the sludge external return pump to 50%. Calculate the difference between the current sludge return ratio and the target return ratio; If the ratio difference is within the error range, the opening of the sludge external return pump will not be initially corrected, and 50% of the opening will be used as the initial opening. If the ratio difference is not within the error range, the opening of the sludge external return pump will be initially corrected to make the ratio difference within the error range, and the initially corrected opening will be used as the initial opening. The initial opening is at most 100% and at least zero.

[0027] Understandably, by setting the opening of the sludge external return pump to 50% as the initial control baseline, and then making initial corrections based on the difference between the current sludge return ratio and the target return ratio, as well as a preset error range, a stable return control state can be quickly established during system startup or operating condition switching. This method avoids the risk of control abrupt changes caused by directly calculating the opening based on the return ratio deviation, allowing the external return pump to smoothly engage and operate under medium load conditions, which helps reduce pump startup shock and pipeline hydraulic fluctuations. When the ratio difference is within the error range, maintaining the opening at 50% can effectively suppress frequent adjustments caused by slight load fluctuations, improving system operational stability. When the ratio difference exceeds the error range, the opening is then specifically corrected to gradually return the return ratio to the target range, thus balancing response speed and control stability. Furthermore, by limiting the upper and lower limits of the initial opening to zero to 100%, it ensures that the control results are always within the safe operating range of the equipment, avoiding overshoot or undershoot that could adversely affect the biological system, and overall improving the reliability and engineering applicability of external return sludge control.

[0028] In one specific embodiment, when the system initiates external sludge return control, the opening degree of the external sludge return pump is initially set to 50%. Subsequently, the initial opening degree setting module calculates the current sludge return ratio based on the average sludge flow rate and the average influent flow rate of the biological treatment tank obtained by the acquisition module. This current sludge return ratio is then compared with a pre-set target return ratio, and the difference between the two is calculated. For example, if the target return ratio is 0.6 and the current sludge return ratio is 0.45, and the calculated difference exceeds a preset error range, the system performs an initial correction to the opening degree of the external return pump. For instance, the opening degree is gradually increased from 50% to 65%, bringing the return ratio closer to the target return ratio. When the current sludge return ratio is 0.58 and within the error range, the opening degree is maintained at 50% as the initial opening degree. Through this method, the opening degree of the external return pump is reasonably initialized, providing a stable control starting point for subsequent fine-tuning based on sludge concentration.

[0029] In some embodiments of this application, when the opening adjustment module is used to determine whether to adjust the initial opening of the sludge external return pump based on the sludge concentration in the current time period, it includes: Within the current time period, several data collection time points are set to obtain the sludge concentration at each data collection time point and calculate the average sludge concentration. The average sludge concentration is compared with a preset concentration range. If the average sludge concentration is within the preset concentration range, it is determined that the initial opening degree will not be adjusted. If the average sludge concentration is not within the preset concentration range, then it is determined that the initial opening degree should be adjusted.

[0030] Understandably, by setting several data collection points within the current time period and calculating the average sludge concentration, then comparing this average concentration with a preset concentration range to determine whether the initial opening of the sludge external return pump needs adjustment, the adverse effects of single-moment measurement errors or instantaneous disturbances on control decisions can be avoided. This method, through multi-point sampling over time, smooths the sludge concentration data, making the judgment results more stable and reliable, thereby reducing frequent opening adjustments caused by short-term concentration fluctuations and helping to maintain the relative stability of the sludge load in the biological treatment tank. Simultaneously, introducing a preset concentration range as a judgment threshold, triggering opening adjustments only when the average sludge concentration significantly deviates from the target operating range, effectively distinguishes between normal operating fluctuations and abnormal operating conditions requiring intervention, improving the targeting and rationality of the control strategy. Furthermore, this judgment method provides clear triggering conditions for the subsequent graded control of the opening adjustment magnitude and method, making the entire external return sludge control process exhibit a coarse-to-fine, step-by-step optimization characteristic, which helps improve the overall system stability and automation level.

[0031] In one specific embodiment, the current time period is set to 10 minutes, and multiple sludge concentration collection time nodes are set at 1-minute intervals within this time period. The collection module acquires sludge concentration data in the external sludge return channel once at each collection time node. The opening adjustment module performs statistical processing on the multiple sets of sludge concentration data collected within the 10 minutes, calculates the average sludge concentration, and compares the average sludge concentration with a preset concentration range. For example, when the preset concentration range is 30 g / L to 40 g / L, and the calculated average sludge concentration is 35 g / L, it is determined that the sludge concentration is within the preset concentration range, and the initial opening of the external sludge return pump is not adjusted; when the average sludge concentration is 46 g / L or 25 g / L, it is determined that the sludge concentration has deviated from the preset concentration range, triggering the adjustment of the initial opening of the external sludge return pump, thereby entering the subsequent opening adjustment steps based on sludge concentration, realizing refined control of the externally returned sludge.

[0032] In some embodiments of this application, when the opening adjustment module is used to adjust the initial opening of the sludge external return pump according to the sludge concentration in the current time period, it includes: If the average sludge concentration is greater than the maximum value of the preset concentration range, the difference between the average sludge concentration and the maximum value of the preset concentration range is calculated and recorded as the first difference. The initial opening is then adjusted by reducing the value based on the first difference. A first range is set. If the first difference is less than the minimum value of the first range, the initial opening is adjusted by a first adjustment coefficient. If the first difference is within the first range, the initial opening is adjusted by a second adjustment coefficient. If the first difference is greater than the maximum value of the first range, the initial opening is adjusted by a third adjustment coefficient. The adjustment coefficient ranges from 1 to 0.5, where the adjusted opening is the product of the initial opening and the adjustment coefficient.

[0033] It is understandable that when the average sludge concentration exceeds the maximum value of the preset concentration range, it indicates that the solid content in the externally returned sludge is too high. If the original opening of the return pump is maintained, it can easily lead to problems such as excessive sludge load in the biological treatment tank, deterioration of mass transfer conditions, and increased operating energy consumption. This invention introduces a first difference to quantify the degree to which the sludge concentration exceeds the preset upper limit, and further combines the first range to classify the difference, so that the adjustment of the external sludge return pump opening can match the degree of sludge concentration excess. For mild over-limit conditions, only a large adjustment coefficient is used to slightly reduce the initial opening to avoid over-control; for moderate or severe over-limit conditions, a smaller adjustment coefficient is used to achieve a more significant opening reduction, thereby effectively reducing the return flow of high-concentration sludge. This graded adjustment method avoids the control abruptness and oscillation problems caused by the traditional single proportional adjustment method, making the externally returned sludge control process smoother and more controllable, which is conducive to maintaining the stability and safety of the biological treatment system, while improving the engineering adaptability of the overall control strategy.

[0034] In one specific embodiment, the preset sludge concentration range is 30 g / L to 40 g / L, the first range is set to 3 g / L to 8 g / L, and the initial opening degree is 60%. When the average sludge concentration calculated in the current time period is 42 g / L, the first difference is 2 g / L, which is less than the minimum value of the first range. The opening degree adjustment module adjusts the initial opening degree using a first adjustment coefficient (preferably 0.95), reducing the opening degree of the external return pump from 60% to 57%. When the average sludge concentration is 45 g / L, the first difference is 5 g / L, which is within the first range. The opening degree adjustment module adjusts the initial opening degree using a second adjustment coefficient (preferably 0.8), reducing the opening degree from 60% to 48%. When the average sludge concentration is 50 g / L, the first difference is 10 g / L, which is greater than the maximum value of the first range. The opening degree adjustment module adjusts the initial opening degree using a third adjustment coefficient (preferably 0.6), reducing the opening degree of the external return pump to 36%. By using the above-mentioned graded reduction and adjustment method, the high concentration of externally returned sludge can be suppressed.

[0035] In some embodiments of this application, when the opening adjustment module is used to adjust the initial opening of the sludge external return pump according to the sludge concentration in the current time period, it further includes: If the average sludge concentration is less than the minimum value of the preset concentration range, the difference between the minimum value of the preset concentration range and the average sludge concentration is calculated and recorded as the second difference. The initial opening is then adjusted by increasing the opening based on the second difference. Specifically, a second range is set. If the second difference is less than the minimum value of the second range, the initial opening is adjusted using a fourth adjustment coefficient. If the second difference is within the second range, the initial opening is adjusted using a fifth adjustment coefficient. If the second difference is greater than the maximum value of the second range, the initial opening is adjusted using a sixth adjustment coefficient. The adjustment coefficient ranges from 1 to the fourth adjustment coefficient, which is less than the fifth adjustment coefficient, which is less than the sixth adjustment coefficient, which is less than 1.5. The adjusted opening is the product of the initial opening and the adjustment coefficient, and the maximum adjusted opening is 100%.

[0036] Understandably, when the average sludge concentration is lower than the minimum value of the preset concentration range, it indicates that the externally returned sludge is diluted. Insufficient returned sludge volume may lead to a decrease in sludge concentration in the biological treatment tank, thereby affecting the treatment efficiency of activated sludge and system stability. This invention quantifies the degree to which the sludge concentration is below the lower limit by calculating a second difference, and further introduces a second range and graded adjustment coefficients (fourth, fifth, and sixth adjustment coefficients) to expand and adjust the initial opening, so that the increase in the opening of the external sludge return pump matches the degree of low sludge concentration. For slightly low concentrations, only a small expansion coefficient is used for moderate increase to avoid excessive pump operation; for moderate or severely low concentrations, a larger expansion coefficient is used to achieve a significant increase in opening, thereby effectively increasing the amount of returned sludge and maintaining the stability of sludge concentration and treatment effect in the biological treatment tank. This graded adjustment strategy makes the control of externally returned sludge more flexible and precise, improves the level of system automation, reduces manual intervention, and optimizes operating energy consumption.

[0037] In one specific embodiment, the preset sludge concentration range is 30 g / L to 40 g / L, the second range is set to 3 g / L to 8 g / L, and the initial opening degree is 50%. When the average sludge concentration calculated in the current time period is 28 g / L, the second difference is 2 g / L, which is less than the minimum value of the second range. The opening degree adjustment module increases the initial opening degree by a fourth adjustment coefficient (preferably 1.05), raising the external return pump opening degree from 50% to 52.5%. When the average sludge concentration is 26 g / L, the second difference is 4 g / L, which is within the second range. The opening degree adjustment module adjusts the initial opening degree by a fifth adjustment coefficient (preferably 1.1), raising the opening degree from 50% to 55%. When the average sludge concentration is 22 g / L, the second difference is 8 g / L, which is greater than the maximum value of the second range. The opening degree adjustment module adjusts the initial opening degree by a sixth adjustment coefficient (preferably 1.3), raising the external return pump opening degree from 50% to 65%. By using the above-mentioned graded expansion and adjustment method, timely compensation for low-concentration externally returned sludge can be achieved, thereby improving the stability of sludge concentration and treatment efficiency in the biological treatment tank.

[0038] In some embodiments of this application, when the opening adjustment module is used to readjust the opening of the sludge external return pump based on the sludge concentration changes over several subsequent time periods, it includes: Obtain the average sludge concentration for each time period within a number of time periods, and calculate the mean difference between adjacent average sludge concentrations. If all mean differences are within the preset difference range, the current opening degree of the sludge external return pump will not be adjusted again; otherwise, it is determined that the current opening degree of the sludge external return pump will be adjusted again.

[0039] It is understandable that sludge concentration may fluctuate in a short period of time. If the pump opening is adjusted solely based on the concentration data of the current period, it is easily affected by instantaneous abnormal data, leading to frequent adjustments of the external return pump opening, thereby increasing pump mechanical wear and energy consumption. This invention obtains the average sludge concentration over several time periods and calculates the difference between the averages of adjacent time periods to determine the concentration change trend. If all the average differences are within a preset range, it indicates that the sludge concentration change is stable, and there is no need to readjust the pump opening. If some average differences exceed the preset range, it is determined that there is a concentration change trend in the system, and the pump opening needs to be readjusted. This method helps to smooth the control signal, avoid frequent operations caused by instantaneous abnormalities, improve the system's operational stability and lifespan, and ensure continuous optimization of the sludge concentration in the biological treatment tank.

[0040] In one specific embodiment, the current time period is set to 10 minutes, and the average sludge concentration within each of the previous three 10-minute periods is obtained, which are 35 g / L, 37 g / L, and 41 g / L, respectively. The difference between adjacent averages is calculated: 37-35=2 g / L, 41-37=4 g / L, with a preset difference range of 0-3 g / L. Since the second average difference of 4 g / L exceeds the preset range, it is determined that the current sludge concentration is trending upward, and the opening of the external return pump needs to be readjusted. The opening adjustment module can appropriately increase the pump opening according to the trend, for example, increasing the current pump opening from 50% to 55%, to increase the amount of externally returned sludge, maintain the sludge concentration in the biological treatment tank within the target range, achieve dynamic and smooth control, and avoid a decrease in treatment efficiency caused by short-term fluctuations.

[0041] In some embodiments of this application, when the opening adjustment module is used to readjust the opening of the sludge external return pump based on the sludge concentration changes over several subsequent time periods, it further includes: Calculate the difference between the average sludge concentration of the last time period and the current time period among several time periods, and record it as the third difference; If the third difference is zero, it is determined that the current opening of the sludge external return pump will not be adjusted again. If the third difference is greater than zero, the opening degree of the current sludge external return pump is increased; if the third difference is less than zero, the opening degree of the current sludge external return pump is decreased.

[0042] In some embodiments of this application, if the third difference is greater than zero, the opening degree of the current sludge external return pump is increased; if the third difference is less than zero, the opening degree of the current sludge external return pump is decreased, including: When the third difference is greater than zero, a first difference threshold is set. If the third difference is less than the first difference threshold and greater than zero, the opening of the sludge external return pump is increased by a first adjustment coefficient. If the third difference is greater than or equal to the first difference threshold, the opening of the sludge external return pump is increased by a second adjustment coefficient. The adjustment coefficient ranges from 1.5 to 1.5. When the third difference is less than zero, a second difference threshold is set. If the third difference is greater than the second difference threshold but less than zero, the opening of the sludge external return pump is reduced using a third adjustment coefficient. If the third difference is less than or equal to the second difference threshold, the opening of the sludge external return pump is reduced using a fourth adjustment coefficient. The adjustment coefficient ranges from 1 to the third adjustment coefficient to the fourth adjustment coefficient to 0.5. The adjusted opening degree is the product of the adjustment coefficient and the current opening degree of the sludge external return pump; wherein, the maximum opening degree after the adjustment is 100%.

[0043] It is understandable that sludge concentration is not only affected by the current time period but also exhibits a certain trend. Ignoring changes in subsequent time periods may lead to delayed or insufficient adjustment of the external return pump's opening. This invention calculates the difference (third difference) between the average sludge concentration of the last time period and the current time period across several time periods to determine the sludge concentration trend, and then adjusts the pump opening accordingly. When the third difference is zero, it indicates that the sludge concentration is stable and no further adjustment is needed; when the third difference is greater than or less than zero, the pump opening is increased or decreased respectively, allowing the external return pump to dynamically respond to concentration changes. Furthermore, by setting a difference threshold and introducing different adjustment coefficients, the pump opening can be finely adjusted according to the concentration change range, avoiding over-adjustment or slow response. This invention facilitates refined and dynamic control of sludge return, improves the operational stability of the biological treatment tank and wastewater treatment efficiency, while reducing pump mechanical wear and energy consumption.

[0044] In one specific embodiment, the average sludge concentration for the current period is set to 38 g / L, and the average concentration for the last period in several subsequent periods is 42 g / L. The third difference is calculated as 42 - 38 = 4 g / L. The first difference threshold is set to 3 g / L, the first adjustment coefficient is 1.05, and the second adjustment coefficient is 1.1. Since the third difference of 4 g / L is greater than the threshold of 3 g / L, the pump opening adjustment module uses the second adjustment coefficient to increase the current pump opening. For example, if the current pump opening is 50%, the adjusted opening will be 50% × 1.1 = 55%, ensuring that the pump opening responds promptly to the rising sludge concentration, increasing the amount of externally returned sludge, achieving dynamic balance control, maintaining the sludge concentration in the biological treatment tank within the target range, and improving the wastewater treatment effect.

[0045] In some embodiments of this application, when the fault early warning module is used to provide early warning of pipeline blockage based on sludge flow rate and residual sludge pump well parameters, it includes: If the sludge flow rate is consistently lower than the preset minimum flow rate for a preset duration, and the sludge depth in the sludge pump well is greater than the preset minimum depth, then it is preliminarily determined that the pipeline is blocked. Once a preliminary diagnosis of pipe blockage is made, the opening of the sludge external return pump is increased to the maximum opening, and the sludge flow rate is continuously monitored. If the sludge flow rate remains unchanged or decreases within a set time, the pipe is determined to be blocked, and a pipe blockage warning is issued.

[0046] Understandably, in wastewater treatment plant sludge return systems, pipe blockage is a significant factor affecting sludge return efficiency and the operational stability of biological treatment tanks. Traditional manual inspection methods suffer from delayed detection and untimely response. This application utilizes a fault early warning module, combining real-time monitoring of sludge flow rate and sludge depth in the pump well, to achieve intelligent prediction of pipe blockage. When the sludge flow rate consistently falls below a set minimum value while the sludge depth in the pump well remains above the set minimum value, a preliminary judgment is made that blockage may exist. Subsequently, by increasing the pump opening to the maximum and continuously monitoring flow changes, the blockage situation is further confirmed, thereby achieving timely early warning.

[0047] In one specific embodiment, the preset minimum flow rate is 10 m³ / h, the minimum sludge depth in the pump well is 1.2 m, and the flow rate is continuously monitored for 5 minutes. When the system detects that the sludge flow rate is below 10 m³ / h for 5 consecutive minutes and the sludge depth in the pump well is greater than 1.2 m, it initially determines that the pipeline may be blocked. Subsequently, the system increases the opening of the external return pump to 100% and continuously monitors the sludge flow rate for the next 5 minutes. If the sludge flow rate does not increase or continues to decrease during this period, the pipeline is determined to be blocked, the system automatically triggers a pipeline blockage warning signal, records the event, and prompts maintenance personnel to handle it in a timely manner, effectively avoiding sludge return interruption and abnormal operation of the biological treatment tank.

[0048] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program goods. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program goods embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0049] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program goods according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0050] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0051] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A sewage plant external return sludge measurement and control system based on ultrasonic cross-correlation method, characterized in that, The method comprises the following steps: The acquisition module is used to acquire sludge parameters of the sludge external reflux channel and the inflow flow rate of the biochemical pool; wherein the sludge parameters include sludge flow rate and sludge concentration; The initial opening setting module is used to calculate the current sludge reflux ratio according to the sludge flow rate and the inflow flow rate of the biochemical pool; the current sludge reflux ratio is compared with the target reflux ratio to control the opening of the sludge external reflux pump, and the initial opening is obtained; The opening adjustment module is used to determine whether to adjust the initial opening of the sludge external reflux pump according to the sludge concentration in the current period; if it is determined that adjustment is needed, the initial opening of the sludge external reflux pump is adjusted according to the sludge concentration in the current period; the current opening of the sludge external reflux pump is adjusted according to the sludge concentration change in the several periods after the current period; The fault early warning module is used to perform pipeline blockage early warning according to the sludge flow rate and the residual sludge pump well parameters.

2. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 1, characterized in that, When the initial opening setting module is used to calculate the current sludge reflux ratio according to the sludge flow rate and the inflow flow rate of the biochemical pool, the following steps are included: The sludge flow rate average value of the sludge flow rate in the set time window and the inflow flow rate average value of the inflow flow rate in the same time window are acquired; The current sludge reflux ratio is the ratio of the sludge flow rate average value to the inflow flow rate average value.

3. The system according to claim 2, wherein, When the initial opening setting module is used to compare the current sludge reflux ratio with the target reflux ratio to control the opening of the sludge external reflux pump and obtain the initial opening, the following steps are included: The opening of the sludge external reflux pump is set to 50% opening; The ratio difference of the current sludge reflux ratio and the target reflux ratio is calculated; An error range is set; if the ratio difference is within the error range, the initial correction of the opening of the sludge external reflux pump is not performed, and the 50% opening is taken as the initial opening; if the ratio difference is not within the error range, the initial correction of the opening of the sludge external reflux pump is performed, so that the ratio difference is within the error range, and the initial corrected opening is taken as the initial opening; Wherein, the initial opening is at most 100% and at least 0.

4. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 3, characterized in that, When the opening adjustment module is used to determine whether to adjust the initial opening of the sludge external reflux pump according to the sludge concentration in the current period, the following steps are included: A plurality of acquisition time nodes are set in the current period, the sludge concentration at each acquisition time node is acquired, and the sludge concentration average value is calculated; The sludge concentration average value is compared with the preset concentration range; if the sludge concentration average value is within the preset concentration range, it is determined that the initial opening is not adjusted; If the sludge concentration average value is not within the preset concentration range, it is determined that the initial opening is adjusted.

5. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 4, characterized in that, When the opening adjustment module is used to adjust the initial opening of the sludge external reflux pump according to the sludge concentration in the current period, the following steps are included: If the sludge concentration average value is greater than the maximum value of the preset concentration range, the difference between the sludge concentration average value and the maximum value of the preset concentration range is calculated, which is recorded as the first difference, and the initial opening is reduced according to the first difference; The first range is set, if the first difference value is less than the minimum value of the first range, the initial opening degree is adjusted by a first adjustment coefficient; if the first difference value is within the first range, the initial opening degree is adjusted by a second adjustment coefficient; if the first difference value is greater than the maximum value of the first range, the initial opening degree is adjusted by a third adjustment coefficient. Wherein, the adjustment coefficient value range is 1> the first adjustment coefficient> the second adjustment coefficient> the third adjustment coefficient> 0.5; wherein, the adjusted opening degree is the product value of the initial opening degree and the adjustment coefficient.

6. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 5, characterized in that, The opening degree adjustment module is used for adjusting the initial opening degree of the sludge external reflux pump according to the sludge concentration of the current period, and further comprises: If the average sludge concentration is less than the minimum value of the preset concentration range, the difference between the minimum value of the preset concentration range and the average sludge concentration is calculated, which is recorded as a second difference value, and the initial opening degree is adjusted according to the second difference value. Wherein, the second range is set, if the second difference value is less than the minimum value of the second range, the initial opening degree is adjusted by a fourth adjustment coefficient; if the second difference value is within the second range, the initial opening degree is adjusted by a fifth adjustment coefficient; if the second difference value is greater than the maximum value of the second range, the initial opening degree is adjusted by a sixth adjustment coefficient. The adjustment coefficient value range is 1< the fourth adjustment coefficient< the fifth adjustment coefficient< the sixth adjustment coefficient< 1.5; wherein, the adjusted opening degree is the product value of the initial opening degree and the adjustment coefficient, and the maximum adjusted opening degree is 100%.

7. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 6, characterized in that, The opening degree adjustment module is used for adjusting the initial opening degree of the sludge external reflux pump according to the sludge concentration of the current period, and further comprises: The average sludge concentration of each period in the several periods is obtained, and the average difference of the adjacent average sludge concentrations is calculated. If all the average differences are within the preset difference value range, the current sludge external reflux pump opening degree is not adjusted again; otherwise, it is judged whether the current sludge external reflux pump opening degree is adjusted again.

8. The sewage plant external return sludge measurement and control system based on the ultrasonic cross-correlation method according to claim 7, characterized in that, The opening degree adjustment module is used for adjusting the initial opening degree of the sludge external reflux pump according to the sludge concentration of the current period, and further comprises: The difference between the average sludge concentration of the last period in the several periods and the current period is calculated, which is recorded as a third difference value. If the third difference value is zero, it is judged that the current sludge external reflux pump opening degree is not adjusted again. If the third difference value is greater than zero, the current sludge external reflux pump opening degree is increased; if the third difference value is less than zero, the current sludge external reflux pump opening degree is decreased.

9. The system according to claim 8, wherein, If the third difference value is greater than zero, the current sludge external reflux pump opening degree is increased; If the third difference value is less than zero, the current sludge external reflux pump opening degree is decreased, comprising: When the third difference value is greater than zero, a first difference value limit is set, if the third difference value is less than the first difference value limit and greater than zero, the current sludge external reflux pump opening is increased by a first adjustment coefficient; if the third difference value is greater than or equal to the first difference value limit, the current sludge external reflux pump opening is increased by a second adjustment coefficient, wherein the adjustment coefficient value range is 1.5>second adjustment coefficient>first adjustment coefficient>1; When the third difference value is less than zero, a second difference value limit is set, if the third difference value is greater than the second difference value limit and less than zero, the current sludge external reflux pump opening is decreased by a third adjustment coefficient; if the third difference value is less than or equal to the second difference value limit, the current sludge external reflux pump opening is decreased by a fourth adjustment coefficient, wherein the adjustment coefficient value range is 1>third adjustment coefficient>fourth adjustment coefficient>0.5; The adjusted opening is the product of the adjustment coefficient and the current sludge external reflux pump opening; wherein the maximum adjusted opening is 100%.

10. The system according to claim 1, wherein the system is characterized by, The fault early warning module is used for pipeline blockage early warning according to sludge flow and residual sludge pump well parameters, comprising: When the sludge flow is continuously less than the pre-set minimum flow for a pre-set time, and the sludge depth in the sludge pump well is greater than the pre-set minimum depth, it is preliminarily judged that the pipeline is blocked; After preliminarily judging that the pipeline is blocked, the opening of the sludge external reflux pump is increased to the maximum opening, and the sludge flow change is continuously monitored, if the sludge flow is unchanged or decreased within the set time, it is determined that the pipeline is blocked, and pipeline blockage early warning is performed.

Images