Sediment thickness detection method and system for sewage sedimentation tank

Abstract

The invention belongs to the technical field of sewage treatment, and discloses a sediment thickness detection method and system for a sewage sedimentation tank, and the method comprises the steps: transmitting a laser beam through a laser transmitter array, collecting the intensity of an optical signal received by each laser receiver, and carrying out the smoothing treatment to obtain the intensity of a smooth signal; according to the smooth signal intensity of a laser receiver located in a clear liquid area of the sedimentation tank, identifying signal attenuation caused by accumulation of a dirt film on the surface of the optical device, and compensating all the smooth signal intensity to obtain compensated smooth signal intensity; according to the compensated smooth signal intensity, determining a scattering ratio and a signal intensity volatility index of each laser receiver; according to the main signal intensity, the scattering ratio and the signal intensity volatility index, the type of a water body medium layer through which each laser beam passes currently is judged; determining the thickness of the sediment according to the judgment result, and performing alarm control according to the thickness of the sediment; therefore, the accuracy of detection results is improved.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and more specifically, to a method and system for detecting sediment thickness in a wastewater sedimentation tank. Background Technology

[0002] During the production of silicon steel strip, a large amount of wastewater is generated in the cleaning and cooling processes. This wastewater needs to be purified before it is discharged. One of the purification processes is sedimentation, which is usually carried out in a wastewater sedimentation tank.

[0003] Wastewater sedimentation tanks are crucial for removing suspended solids and clarifying wastewater. To optimize sedimentation tank operation and ensure effluent quality, real-time and accurate monitoring of sediment thickness at the bottom of the tank is essential. Currently, an optical-based detection method is widely used. This method utilizes the propagation characteristics of laser beams in water by placing laser emitter and receiver arrays opposite each other on both sides of the sedimentation tank to determine the sediment interface. However, in actual operation, especially when the wastewater composition becomes complex, this optical measurement method faces multiple interferences, leading to measurement deviations and consequently affecting the efficiency and stability of wastewater treatment.

[0004] Specifically, the particulate matter in the industrial wastewater generated during silicon steel strip production forms a widely distributed transition zone in the upper and middle parts of the sedimentation tank. This transition zone has a turbidity level between the supernatant and the dense sludge at the bottom. When a laser beam passes through this transition zone, numerous fine particles scatter and partially absorb the laser light, significantly weakening the light signal reaching the receiver. Furthermore, due to water flow disturbances, the signal strength fluctuates irregularly. At this point, the control logic, which previously relied on simple signal presence or threshold judgments, fails. The system incorrectly interprets this attenuated signal as "signal blockage," thus believing that the sludge-water interface has risen to this turbid transition zone. This leads to premature activation of the sludge pump, resulting in wasted energy and an increased burden on subsequent sludge treatment.

[0005] Furthermore, if the particulate matter in industrial wastewater has strong reflective properties, the light scattering effect may cause some light rays that should be directed at one laser receiver to be scattered onto an adjacent, lower laser receiver that should be blocked. This can lead the system to mistakenly believe that the sludge layer below is still transparent, thus severely underestimating the actual sludge deposition thickness. In this situation, the sludge discharge command cannot be issued for a long time, and the dense sludge layer at the bottom will continue to accumulate. Once it exceeds the design capacity of the sedimentation tank, the sludge may be carried out of the sedimentation tank by the water flow and enter the next treatment unit, causing water quality deterioration throughout the entire treatment process, and may even lead to a serious accident where the final effluent quality fails to meet standards.

[0006] Furthermore, the combined action of these fine particles and microorganisms in the wastewater easily forms a biofilm on the surface of the optical lenses (or the light-transmitting areas on the protective housings of laser transmitters and receivers) submerged in water. This biofilm gradually thickens over time, causing a fixed and continuous attenuation of both emitted and incident laser light. This signal attenuation caused by contamination of the equipment itself is very similar in appearance to signal attenuation caused by sludge in the water. The system cannot distinguish the root cause of the signal weakening and may misinterpret lens contamination as an increase in the sludge layer, thus issuing continuous false alarms or providing a measurement reading that is completely deviated from reality and remains persistently high. To solve this problem, maintenance personnel have to frequently remove the equipment from the pool for manual cleaning, which not only increases the workload significantly but also greatly reduces the continuous availability of the system, thus failing to achieve the original intention of automated monitoring.

[0007] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0008] The purpose of this application is to provide a method and system for detecting sediment thickness in sewage sedimentation tanks, aiming to solve the problem that existing methods for detecting sediment thickness in sewage sedimentation tanks are easily affected by factors such as turbidity transition layers, light scattering effects, and the accumulation of dirt films on the surface of optical devices in complex sewage environments, resulting in inaccurate measurement results and thus affecting sewage treatment efficiency and stability.

[0009] In a first aspect, this application provides a method for detecting the sediment thickness in a sewage sedimentation tank, which detects the sediment thickness in the sewage sedimentation tank based on a laser emitter array and a laser receiver array. The laser emitter array includes multiple laser emitters arranged in a vertical direction, and the laser receiver array includes multiple laser receivers arranged in a vertical direction. Each laser receiver includes a main photoelectric detection unit arranged horizontally and coaxially with one of the laser emitters and an auxiliary photoelectric detection unit misaligned with the optical axis of the laser emitter. The method for detecting sediment thickness in the wastewater sedimentation tank includes: A1. A laser beam is emitted using a laser emitter array, and the intensity of the light signal received by each laser receiver is collected. The intensity of the light signal is then smoothed to obtain a smoothed signal intensity. A2. Based on the smoothed signal intensity of the laser receiver located in the clear liquid zone of the sedimentation tank, identify the signal attenuation caused by the accumulation of dirt film on the surface of the optical device, and use this information to compensate for all the smoothed signal intensities to obtain the compensated smoothed signal intensity. A3. Based on the compensated smooth signal intensity, determine the scattering ratio of each laser receiver and the signal intensity fluctuation index; the scattering ratio is the ratio between the main signal intensity and the auxiliary signal intensity, the main signal intensity is the compensated smooth signal intensity of the main photoelectric detection unit, and the auxiliary signal intensity is the compensated smooth signal intensity of the auxiliary photoelectric detection unit. A4. Based on the main signal intensity, the scattering ratio, and the signal intensity fluctuation index, determine the type of water medium layer that each laser beam is currently passing through; the water medium layer types include clear liquid layer, turbid transition layer, and dense sediment layer; A5. Based on the water medium layer type identification results, determine the sediment thickness and implement alarm control based on the sediment thickness.

[0010] Secondly, this application provides a sediment thickness detection system for a sewage sedimentation tank, including a main controller, a laser emitter array, a laser receiver array, and an alarm device, wherein the laser emitter array, the laser receiver array, and the alarm device are all electrically connected to the main controller; The laser emitter array includes multiple laser emitters arranged in a vertical direction, and the laser receiver array includes multiple laser receivers arranged in a vertical direction. Each laser receiver includes a main photoelectric detection unit that is horizontally coaxial with one of the laser emitters and an auxiliary photoelectric detection unit that is misaligned with the optical axis of the laser emitter. The main controller is used to execute the steps of the sediment thickness detection method for the sewage sedimentation tank described above.

[0011] Beneficial effects: The sediment thickness detection method and system provided in this application for sewage sedimentation tank effectively solves the measurement inaccuracies caused by factors such as complex sewage composition, turbidity transition layer, light scattering effect and dirt film accumulation on the surface of optical devices in the prior art through innovative optical device configuration, dirt film accumulation compensation mechanism and multi-dimensional feature discrimination method. It significantly improves the accuracy, reliability and automation level of sediment thickness detection. Attached Figure Description

[0012] Figure 1 A flowchart of a method for detecting sediment thickness in a wastewater sedimentation tank provided in this application.

[0013] Figure 2 This is a schematic diagram of a sediment thickness detection system for a sewage sedimentation tank provided in this application.

[0014] Figure 3 A block diagram of a sediment thickness detection system for a wastewater sedimentation tank provided in this application.

[0015] Labeling Explanation: 1. Main Controller; 2. Laser Emitter Array; 201. Laser Emitter; 3. Laser Receiver Array; 301. Laser Receiver; 302. Main Photoelectric Detection Unit; 303. Auxiliary Photoelectric Detection Unit; 4. Alarm Device; 5. Frame; 6. Light-Transmitting Protective Housing; 7. Drive Unit; 8. Support Frame; 9. Control Box; 90. Sewage Sedimentation Tank. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0017] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] Please refer to Figures 1-3 This application discloses a method for detecting sediment thickness in a wastewater sedimentation tank, which uses a laser emitter array and a laser receiver array to detect sediment thickness. The laser emitter array includes multiple laser emitters arranged vertically, and the laser receiver array includes multiple laser receivers arranged vertically. Each laser receiver includes a main photoelectric detection unit horizontally coaxial with a laser emitter and an auxiliary photoelectric detection unit misaligned with the optical axis of the laser emitter (e.g., horizontally). Figure 2 , Figure 3 (The shown is a sediment thickness detection system for a wastewater sedimentation tank). The methods for detecting sediment thickness in this wastewater sedimentation tank include: A1. A laser beam is emitted using a laser emitter array, and the intensity of the light signal received by each laser receiver is collected. The light signal intensity is then smoothed to obtain a smoothed signal intensity. A2. Based on the smooth signal intensity of the laser receiver located in the clear liquid zone of the sedimentation tank, identify the signal attenuation caused by the accumulation of dirt film on the surface of the optical device, and use it to compensate for all smooth signal intensities to obtain the compensated smooth signal intensity. A3. Based on the compensated smooth signal intensity, determine the scattering ratio of each laser receiver and the signal intensity fluctuation index; the scattering ratio is the ratio between the main signal intensity and the auxiliary signal intensity, the main signal intensity is the compensated smooth signal intensity of the main photoelectric detection unit, and the auxiliary signal intensity is the compensated smooth signal intensity of the auxiliary photoelectric detection unit. A4. Based on the main signal intensity, scattering ratio, and signal intensity fluctuation index, determine the type of water medium layer that each laser beam is currently passing through; the types of water medium layers include clear liquid layer, turbid transition layer, and dense sediment layer; A5. Based on the water medium layer type identification results, determine the sediment thickness and implement alarm control based on the sediment thickness.

[0019] This application, by introducing an auxiliary photoelectric detection unit, fouling film accumulation compensation, scattering ratio and signal intensity fluctuation index, and combining a multi-dimensional discrimination and correction mechanism, can effectively distinguish different water media layers, overcome the limitations of traditional optical detection methods in complex sewage environments, and significantly improve the accuracy and reliability of sediment thickness detection.

[0020] Specifically: In step A1, each laser emitter can periodically emit laser pulses or continuous laser beams. Each laser receiver in the laser receiver array, its main photodetector unit and auxiliary photodetector unit, can employ photoelectric conversion devices such as photodiodes or photomultiplier tubes to convert the received optical signal into an electrical signal. The intensity of these electrical signals represents the strength of the optical signal. To eliminate transient noise and improve signal stability, the intensity of the acquired raw optical signal can be smoothed. Smoothing can be achieved using algorithms such as moving average filtering, exponential smoothing filtering, or Kalman filtering. For example, a sliding window can be used to average multiple continuously acquired optical signal intensity values ​​to obtain the smoothed signal intensity at the current moment.

[0021] In step A2, the laser receiver in the clear liquid zone is typically located at the top of the sedimentation tank, where the water is relatively clear and less affected by sediment. Therefore, a long-term stable decrease in its signal strength is often due to the accumulation of a fouling film on the surface of the optical device. The laser receiver in the clear liquid zone can be pre-specified according to actual needs (e.g., based on the water level in the sewage sedimentation tank). Identifying the signal attenuation caused by fouling film accumulation can be achieved by monitoring the trend of the smoothed signal strength change of the laser receiver in the clear liquid zone over a period of time. For example, a reference signal strength can be set; when the smoothed signal strength of the laser receiver in the clear liquid zone is consistently lower than this reference value and its fluctuation is small, fouling film accumulation is considered to exist. The signal attenuation can be calculated as the difference between the reference signal strength and the current smoothed signal strength. After obtaining the signal attenuation, it is added back to the smoothed signal strength collected by all the laser receivers to compensate for the impact of fouling film accumulation, resulting in a more accurate compensated smoothed signal strength.

[0022] In step A3, the scattering ratio is calculated directly by dividing the compensated smoothed signal intensity received by the main photodetector unit by the compensated smoothed signal intensity received by the auxiliary photodetector unit. The signal intensity fluctuation index is used to quantify signal stability. For example, it can calculate the standard deviation of the main signal intensity within a preset time window, or the instantaneous rate of change of the main signal intensity over a short period, as well as the average duration and frequency of instantaneous events that identify drastic changes in the main signal intensity. These indices can comprehensively reflect the dynamic characteristics of particulate matter and water flow disturbance in the water body.

[0023] In step A4, the discrimination process can be based on preset characteristic patterns. For example, a clear liquid layer typically exhibits high main signal intensity, low scattering ratio, and low volatility; a dense sediment layer exhibits extremely low main signal intensity (even close to zero), a scattering ratio that may be high or low (depending on sediment characteristics), and low volatility; a turbid transition layer may exhibit moderate main signal intensity, high scattering ratio, and high volatility. By matching the measurement data of each laser beam with these preset characteristic patterns, the type of water medium layer to which it belongs can be preliminarily determined. To improve the discrimination accuracy, the discrimination results of adjacent laser beams can be combined for correction, for example, by using majority voting or weighted averaging methods.

[0024] In step A5, once the water medium layer type of all laser beams is accurately identified, the laser emitter corresponding to the first laser beam identified from top to bottom as a dense sediment layer can be identified. The height of this laser emitter is considered the upper surface of the sediment, thereby determining the sediment thickness. For example, the height of each laser emitter relative to the bottom of the sedimentation tank can be pre-calibrated. When the sediment thickness exceeds a preset thickness threshold, the system can issue a warning command, such as through an audible and visual alarm, sending a text message or email, notifying maintenance personnel that sludge removal is required, or automatically starting the sludge removal pump to perform sludge removal.

[0025] The sediment thickness detection method for wastewater sedimentation tanks proposed in this application effectively solves the challenges encountered by existing technologies in complex wastewater environments by introducing multi-dimensional characteristic parameters and a refined discrimination mechanism. Traditional methods often rely solely on a single signal intensity threshold for judgment, making it difficult to distinguish between various interfering factors such as turbidity transition layers, light scattering effects, and the accumulation of dirt films on the surfaces of optical devices. For example, when a turbidity transition layer exists in the wastewater, traditional methods may misjudge it as a rise in the mud-water interface due to signal attenuation, leading to excessive sludge discharge. This application, by introducing the auxiliary photoelectric detection unit and calculating the scattering ratio, can effectively capture the scattering characteristics of particulate matter in the water, thereby distinguishing between the turbidity transition layer and the dense sediment layer. Furthermore, by monitoring and compensating the signal of the laser receiver in the clear liquid zone, this application can accurately identify and eliminate signal attenuation caused by the accumulation of dirt films on the surfaces of optical devices, avoiding misjudgments and frequent manual cleaning due to equipment contamination.

[0026] Compared with existing technologies, the advantages of this application are as follows: First, by combining the main photoelectric detection unit and the auxiliary photoelectric detection unit, more comprehensive information on the propagation of the laser beam in the water body can be obtained, especially the quantification of the scattering effect, making the identification of the turbidity transition layer more accurate. Second, the fouling film accumulation compensation mechanism effectively solves the measurement drift problem caused by optical device contamination during long-term operation, improving the long-term stability and maintenance-free nature of the system. Third, by combining the main signal intensity, the scattering ratio, and the signal intensity fluctuation index for comprehensive discrimination, different water medium layers can be identified more robustly, reducing the false judgment rate. Finally, by alarm control based on the discrimination results, intelligent management of the sedimentation tank operation is realized, avoiding resource waste and environmental risks caused by excessive sediment accumulation or excessive sludge discharge. Therefore, this application has significant technological progress and practical value in the detection of sediment thickness in sewage sedimentation tanks.

[0027] In some implementations, step A2 includes: A201. Within a preset time window, calculate the rate of decrease of the smoothed signal intensity and the fluctuation level of the smoothed signal intensity for the laser receiver located in the clear liquid zone of the sedimentation tank. A202. Based on the descent rate and fluctuation level, determine whether the descent rate is lower than the preset rate threshold and whether the fluctuation level remains within the preset level range; A203. If the descent rate is lower than the preset rate threshold and the fluctuation level remains within the preset level range, it is determined that there is dirt film accumulation on the surface of the optical device, and the current smooth signal intensity of the laser receiver in the sedimentation tank clear liquid area is compared with the preset reference signal intensity to obtain the signal attenuation caused by dirt film accumulation; otherwise, the signal attenuation is set to zero. A204. Based on the signal attenuation, compensate for the strength of all smoothed signals to obtain the compensated smoothed signal strength.

[0028] Specifically, in step A201, the preset time window refers to a continuous time period used to accumulate and analyze signal data to capture the trend and stability of signal changes. The rate of decrease can be understood as the amount of change in signal strength per unit time, reflecting the speed at which the signal strength decreases over time. For example, the rate of decrease can be obtained by dividing the difference between the maximum and minimum signal strength values ​​within the preset time window by the length of the time window. The fluctuation level can be understood as the degree of dispersion or stability of the signal strength within the time window, and can be measured by standard deviation or variance. As a preferred implementation, the calculation can primarily focus on the rate of decrease and fluctuation level corresponding to the main photoelectric detection unit, or it can be calculated by combining the rate of decrease and fluctuation levels of the main photoelectric detection unit and the auxiliary photoelectric detection unit (e.g., taking an average or weighted average) to provide more comprehensive signal characteristic information.

[0029] In step A202, the preset rate threshold is an empirical value or a critical value determined through calibration, used to distinguish between normal signal fluctuations and a slow decline caused by the accumulation of fouling film. The preset level range defines the interval within which signal fluctuations are considered stable; exceeding this range may indicate the presence of other interferences or changes in the water medium.

[0030] Specifically, in step A203, when the signal strength decreases slowly and the fluctuations remain stable, this is typically a characteristic of fouling film accumulation, as fouling film formation is a gradual and relatively stable process. The preset reference signal strength can be the signal strength measured when the optical device is clean, or a reference value set during the initial stage of normal system operation. By comparing the current signal strength with the reference signal strength, the degree of signal attenuation caused by fouling film accumulation can be quantified.

[0031] Therefore, in step A204, by adding the identified signal attenuation back to the smooth signal intensity measured by all laser receivers, the influence of dirt film accumulation on the measurement results can be effectively eliminated, the true signal intensity can be restored, and a more accurate data basis can be provided for subsequent water medium layer type identification.

[0032] This application's solution, by introducing a comprehensive judgment of the rate of decline and fluctuation level of smooth signal intensity, can more accurately identify the accumulation of dirt film on the surface of optical devices. Specifically, the accumulation of dirt film is usually a slow and continuous process, manifested as a gradual decrease in signal intensity at a low rate, while the water medium is relatively stable in the clear liquid zone, keeping the signal fluctuation level within a low preset range. In contrast, if the signal intensity decreases rapidly or the fluctuation level is high, it is more likely due to changes in the turbidity of the water medium itself or other transient interferences. Through this dual judgment mechanism, this application can effectively distinguish between signal attenuation caused by dirt film accumulation and signal changes caused by other factors, thereby avoiding misjudgment and inaccurate compensation.

[0033] Through the above technical solution, this application can more accurately identify the signal attenuation caused by the accumulation of dirt film on the surface of optical devices and perform precise compensation. This significantly improves the reliability and accuracy of signal data and avoids compensation errors caused by misjudging the accumulation of dirt film. Therefore, it provides more realistic and reliable input data for subsequent identification of the water medium layer type, thereby improving the overall accuracy and stability of sediment thickness detection in wastewater sedimentation tanks, ensuring that the system can perform alarm control based on accurate data, and effectively guiding the operation and management of sedimentation tanks.

[0034] In some implementations, step A3 includes steps performed for each laser receiver: A301. Calculate the ratio between the main signal intensity and the auxiliary signal intensity of the laser receiver, and use it as the scattering ratio of the laser receiver; A302. Calculate the standard deviation of the main signal strength within a preset time window; A303. Calculate the instantaneous rate of change of the main signal strength at each moment within a preset time window; A304. Based on the instantaneous rate of change, identify instantaneous events with drastic changes in signal strength, and determine the average duration and frequency of occurrence of the instantaneous events; A305. Standard deviation, instantaneous rate of change, average duration, and frequency of occurrence are used as indicators of signal strength volatility.

[0035] Specifically, in step A301, the scattering ratio refers to the ratio between the main signal intensity and the auxiliary signal intensity. The main signal intensity is the compensated, smoothed signal intensity of the main photodetector unit, and the auxiliary signal intensity is the compensated, smoothed signal intensity of the auxiliary photodetector unit. Calculating this ratio reflects the change in the light signal distribution caused by scattering from particles in the water medium as the laser beam passes through it. For example, when the concentration of particles in the water medium is high, the scattering effect is enhanced, and the intensity of the scattered light signal received by the auxiliary photodetector unit will relatively increase, thus affecting the scattering ratio.

[0036] In step A302, the standard deviation of the main signal strength within a preset time window is calculated. The standard deviation is a statistic that measures the dispersion of data; its purpose is to quantify the fluctuation range of the signal strength received by the main photoelectric detection unit over a period of time. A larger standard deviation usually indicates significant random or periodic fluctuations in the signal strength, which may be related to the random movement of particles or local concentration changes in the water medium.

[0037] In step A303, the instantaneous rate of change of the main signal intensity at various moments within a preset time window is calculated. The instantaneous rate of change reflects how quickly the signal intensity changes over time, and its purpose is to capture rapid increases or decreases in signal intensity. For example, when a laser beam suddenly encounters a high concentration of particulate matter or bubbles, the signal intensity may undergo a drastic instantaneous change. The instantaneous rate of change at a certain moment can be obtained by dividing the difference in main signal intensity between that moment and the previous moment by the data sampling time interval.

[0038] In step A304, based on the instantaneous rate of change, instantaneous events characterized by drastic changes in signal strength are identified, and the average duration and frequency of these events are determined. An instantaneous event refers to a phenomenon where signal strength deviates significantly from normal levels within a short period, such as that caused by bubbles, large particles, or localized turbulence. Whether the signal strength changes drastically can be determined by comparing the instantaneous rate of change with a preset rate of change threshold. By identifying these events and quantifying their duration and frequency, the dynamic characteristics of the aquatic medium can be described more precisely. For example, the duration can be the duration for which the instantaneous rate of change remains above a preset rate of change threshold, and the frequency can be obtained by dividing the number of instantaneous events occurring within a preset time window by the length of the time window.

[0039] In step A305, the standard deviation, the instantaneous rate of change, the average duration, and the frequency of occurrence are used as the signal strength volatility indicators. These indicators comprehensively reflect various fluctuation characteristics of the main signal strength in the time dimension, including overall dispersion, instantaneous rate of change, and characteristics of specific events. By combining this multi-dimensional volatility information, the complex dynamic behavior of the water medium can be more comprehensively and accurately characterized.

[0040] This application's scheme, through detailed quantification of scattering ratio and signal intensity fluctuation indices, can more comprehensively capture the optical characteristics of a laser beam passing through an aquatic medium. The calculation of the scattering ratio utilizes the synergistic effect of the main photodetector unit and the auxiliary photodetector unit. The main photodetector unit primarily receives direct light, while the auxiliary photodetector unit receives more scattered light. The ratio of these two units can effectively distinguish the differences in the scattering effect of particles on the laser in the clear liquid layer, the turbid transition layer, and the dense sediment layer. For example, in the clear liquid layer, the scattering effect is weak, and the scattering ratio may be close to a certain baseline value; while in the turbid transition layer or the dense sediment layer, due to changes in particle concentration and size distribution, the scattering effect is enhanced, and the scattering ratio will change significantly.

[0041] Furthermore, by introducing multi-dimensional signal strength fluctuation indicators, including standard deviation, instantaneous rate of change, average duration of instantaneous events, and frequency of occurrence, this application can deeply analyze the dynamic behavior of signal strength over time. Standard deviation provides a macroscopic view of the overall signal stability; instantaneous rate of change captures the signal's rapid response characteristics; and the identification of instantaneous events and the quantification of their duration and frequency of occurrence can effectively distinguish signal fluctuations caused by different factors such as bubbles, flocs, or local turbulence. For example, the presence of bubbles may cause a rapid decrease and quick recovery of signal strength, characterized by a high instantaneous rate of change, a short average duration, and a relatively high frequency of occurrence; while the passage of flocs may cause a slow decrease in signal strength that persists for a period of time, characterized by a lower instantaneous rate of change, a longer average duration, and a lower frequency of occurrence. These subtle fluctuation characteristics, combined with the scattering ratio, constitute the unique "fingerprint" of the water medium layer, thus providing a solid data foundation for accurately identifying the type of water medium layer in subsequent step A4.

[0042] By employing the aforementioned technical solutions, detailed calculations and comprehensive consideration of scattering ratio and signal intensity fluctuation indices can significantly improve the accuracy and robustness in distinguishing different water media layers (clear liquid layer, turbid transition layer, and dense sediment layer) in wastewater sedimentation tanks. Traditional detection methods may rely solely on signal intensity attenuation, making it difficult to effectively differentiate signal changes caused by fouling film accumulation, bubbles, flocs, or actual sediment layers. This application, by introducing scattering ratio, effectively utilizes scattered light information to enhance sensitivity to changes in particulate matter concentration and distribution. Simultaneously, through multi-dimensional analysis of signal intensity fluctuations, the dynamic characteristics of the water media can be captured more precisely, thus avoiding misjudging temporary local disturbances as sediment layers or confusing different types of media layers. Therefore, this application can provide more accurate and reliable sediment thickness detection results, providing strong support for the optimized control of wastewater treatment processes.

[0043] In some implementations, step A4 includes: A401. Based on the main signal intensity, scattering ratio, and signal intensity fluctuation index, calculate the matching degree between each laser beam and the preset characteristic mode of the clear liquid layer, turbid transition layer, and dense sediment layer. A402. Based on the matching degree, the type of water medium layer that each laser beam is currently passing through can be preliminarily determined; A403. Based on the matching degree, identify the laser beam that simultaneously meets the preset matching degree range of the turbid transition layer and the dense sediment layer as the laser beam in the transition region; A404. The preliminary judgment result is corrected by combining the matching degree of the laser beams adjacent above and below the laser beam in the transition region.

[0044] Specifically, in step A401, the preset feature patterns refer to mathematical models or datasets pre-established to characterize the typical features of the three water media types: clear liquid layer, turbid transition layer, and dense sediment layer. These patterns can be constructed based on historical data, experimental results, or expert experience. For example, they may include characteristic values ​​or distributions of typical main signal intensity ranges, scattering ratio ranges, and signal intensity fluctuation indices for each layer. Calculating the matching degree involves comparing the main signal intensity, scattering ratio, and signal intensity fluctuation indices measured by the current laser beam with each preset feature pattern to quantify their similarity. For example, it involves calculating the distance (such as Euclidean distance or Mahalanobis distance) between the current measurement value (i.e., a multidimensional feature vector composed of main signal intensity, scattering ratio, and signal intensity fluctuation indices) and the preset feature pattern in the multidimensional feature space. The smaller the distance, the higher the similarity. A higher matching degree indicates that the water media type traversed by the current laser beam is closer to the preset pattern.

[0045] In step A402, the preliminary discrimination refers to assigning the most likely water medium layer type to each laser beam based on the calculated matching degree. For example, the water medium layer type with the highest matching degree to a certain laser beam can be selected as its preliminary discrimination result.

[0046] In practical applications, step A403 identifies laser beams located in transition regions to address ambiguous boundaries between layers. When the matching degree of a laser beam simultaneously meets the preset matching degree range of both the turbid transition layer and the dense sediment layer, it indicates that the laser beam may be located in the boundary region between these two layers, and its signal characteristics combine those of both, thus it is identified as a laser beam in the transition region. This facilitates subsequent fine-tuning.

[0047] Furthermore, in step A404, the preliminary discrimination result is corrected. The purpose is to improve the accuracy and robustness of the discrimination by utilizing the spatial correlation between adjacent laser beams. Since the water medium layer in the sewage sedimentation tank is usually continuously distributed, the medium layer types traversed by adjacent laser beams are often the same or gradually changing. Therefore, by combining the matching degree information of adjacent laser beams, misjudgments caused by local anomalies or signal fluctuations of a single laser beam can be effectively corrected, making the final discrimination result more consistent with the actual layered structure.

[0048] This application's solution effectively addresses the potential boundary ambiguity and misjudgment problems in traditional methods for identifying water medium layer types by introducing preset feature pattern matching, preliminary discrimination, transition region identification, and adjacent laser beam information correction. First, by calculating the matching degree between each laser beam and the preset feature patterns of the clear liquid layer, turbid transition layer, and dense sediment layer, the signal characteristics of each laser beam can be quantitatively evaluated, providing a more refined basis for subsequent discrimination. Second, preliminary discrimination based on the matching degree allows for rapid initial classification of each laser beam. More importantly, by identifying laser beams that simultaneously meet the preset matching degree ranges of the turbid transition layer and dense sediment layer as laser beams in the transition region, this application can accurately locate areas with unclear signal characteristics and easy confusion, avoiding the rigid classification errors that may result from simple threshold discrimination. Finally, the preliminary discrimination results are corrected by combining the matching degree of the laser beams adjacent above and below the laser beam in the transition region. By utilizing the spatial continuity of the water medium layer and considering local environmental information, the discrimination results are effectively smoothed and abnormal discrimination that may exist in a single laser beam is corrected, thereby significantly improving the accuracy and robustness of water medium layer type discrimination.

[0049] Through the above technical solution, this application can achieve more accurate and robust identification of the type of water media layer in sewage sedimentation tanks. Compared with methods that rely solely on signal strength, scattering ratio, and signal strength fluctuation indicators for direct identification, this application introduces preset feature pattern matching, making the identification process more quantitative and objective. By identifying transition regions and combining information from adjacent laser beams for correction, it effectively solves the problems of misjudgment caused by blurred interlayer boundaries and local signal fluctuations, significantly improving the accuracy and stability of the identification results. Therefore, it can more accurately determine the location and thickness of the sediment layer, providing reliable data support for the refined control of the sewage treatment process, avoiding excessive or insufficient sediment discharge due to inaccurate identification, thereby improving sewage treatment efficiency and effluent quality.

[0050] Preferably, step A402 may include: For each laser beam, the matching degree between the laser beam and the preset characteristic patterns of the clear liquid layer, the turbid transition layer and the dense sediment layer is compared. The water medium layer type with the highest matching degree is selected as the preliminary judgment result of the water medium layer type that the laser beam is currently passing through.

[0051] This application's solution establishes unique preset characteristic patterns for each type of water medium layer (clear liquid layer, turbid transition layer, and dense sediment layer), and calculates the matching degree between the actual measurement data of each laser beam (main signal intensity, scattering ratio, and signal intensity fluctuation index) and these preset patterns, thereby achieving preliminary identification of the water medium layer type. Because different water medium layers exhibit significant differences in optical properties, such as varying absorption, scattering, and transmission capabilities for laser light, their main signal intensity, scattering ratio, and signal intensity fluctuation index each display their own typical characteristics. By quantitatively comparing the actually observed signal characteristics with these preset typical patterns and selecting the type with the highest matching degree, the type of water medium layer traversed by the current laser beam can be directly and effectively identified. This discrimination mechanism based on maximizing the matching degree allows the system to utilize the inherent optical fingerprints of each medium layer for preliminary, data-driven classification.

[0052] The above technical solution provides a direct and efficient method for preliminary identification of water medium layer types. This method utilizes the unique preset characteristic patterns of different water medium layers (clear liquid layer, turbid transition layer, and dense sediment layer). By quantitatively comparing the matching degree between the actual measurement data of each laser beam and these patterns, the method selects the one with the highest matching degree as the preliminary judgment result. This identification method has the advantages of clear logic and ease of implementation, enabling rapid preliminary classification of water medium layers traversed by each laser beam. This lays a solid foundation for subsequent corrections and final sediment thickness determination, improving the automation and accuracy of the identification process.

[0053] Further, step A404 may include: B1. Each laser beam in the transition region is used as the target laser beam in turn; B2. Based on the self-matching degree of the target laser beam and the matching degree of the laser beams above and below it, calculate the support of the self-matching degree and the matching degree of the laser beams above and below it for the clear liquid layer, the turbid transition layer and the dense sediment layer respectively. B3. Calculate the total support for the clear liquid layer, the turbid transition layer, and the dense sediment layer based on the support. B4. Select the water medium layer type with the highest total support as the preliminary correction result for the water medium layer type currently traversed by the target laser beam; B5. After completing the initial correction of the water medium layer type of all laser beams in the transition zone, identify the laser beam with the highest position and the water medium layer type as a turbid transition layer as the first laser beam, and identify the laser beam with the lowest position and the water medium layer type as a turbid transition layer as the second laser beam. B6. Correct all water media layers currently traversed by laser beams higher than the first laser beam to clear liquid layers, correct all water media layers currently traversed by the first laser beam to turbid transition layers, and correct all water media layers currently traversed by laser beams lower than the second laser beam to dense sediment layers.

[0054] Specifically, in step B1, the system iterates through all laser beams identified as being in the transition region and treats each one as the target laser beam for current processing. Laser beams in the transition region refer to those whose matching degree simultaneously meets the preset matching degree range of the turbid transition layer and the dense sediment layer, indicating that there is ambiguity in the type of water medium layer they pass through.

[0055] In step B2, for each target laser beam, not only its own matching degree is considered, but also the matching degrees of the laser beams immediately above and below it. These matching degrees are used to calculate the support for the clear liquid layer, turbid transition layer, and dense sediment layer, respectively. Support can be understood as the tendency or strength of evidence that the matching degree of a laser beam and its adjacent laser beams indicates for a specific type of aquatic medium.

[0056] In step B3, the total support for each water medium layer type is calculated by aggregating the support of the target laser beam and its adjacent laser beams. The total support reflects the overall probability that the target laser beam belongs to a certain water medium layer type after considering local contextual information.

[0057] In step B4, the water medium layer type with the highest overall support is taken as the initial correction result for the target laser beam. This means that, within a local range, by comprehensively considering information from the target laser beam and its adjacent laser beams, a more reliable determination of the water medium layer type of the laser beam is made.

[0058] In step B5, after all laser beams in the transition region have undergone initial correction, the system performs a global layer boundary identification. Specifically, it scans the initial correction results of all laser beams from top to bottom, identifies the first laser beam corrected to a cloudy transition layer, and marks it as the first laser beam. Simultaneously, it identifies the lowest-positioned laser beam, also corrected to a cloudy transition layer, and marks it as the second laser beam. The first and second laser beams together define the approximate vertical extent of the cloudy transition layer.

[0059] In step B6, a final global correction is performed based on the turbidity transition layer range determined by the first and second laser beams. All laser beams positioned above the first laser beam will have their water medium layer type uniformly corrected to a clear liquid layer. All laser beams positioned between the first and second laser beams (including the first and second laser beams themselves) will have their water medium layer type uniformly corrected to a turbidity transition layer. All laser beams positioned below the second laser beam will have their water medium layer type uniformly corrected to a dense sediment layer. This correction method ensures the continuity and rationality of the water medium layer type determination results in the vertical direction, avoiding local inconsistencies.

[0060] This application's solution effectively addresses the potential local inconsistencies and ambiguities in the initial discrimination results by introducing support calculations based on the matching degree of the target laser beam and its adjacent laser beams, and then performing global corrections accordingly. Specifically, steps B1 to B4 calculate the support degree for different water medium layer types by considering the local contextual information of the target laser beam (i.e., the matching degree of adjacent laser beams), thus making the initial correction results for laser beams in transition regions more reliable. This local correction avoids misjudgments that may arise from relying solely on the matching degree of a single laser beam. Furthermore, after completing all local corrections, steps B5 and B6 perform a global, hierarchical correction of the water medium layer type for all laser beams by identifying the upper and lower boundaries of the turbidity transition layer (the first laser beam and the second laser beam). This global correction mechanism forcibly ensures a reasonable vertical layering structure of the clear liquid layer, the turbidity transition layer, and the dense sediment layer, with the clear liquid layer at the top, the turbidity transition layer in the middle, and the dense sediment layer at the bottom. Therefore, even with slight deviations in local discrimination, the final correction result can still present a clear, continuous, and physically consistent distribution of the water medium layer, thereby improving the accuracy and stability of sediment thickness determination.

[0061] Through the above technical solution, this application overcomes the limitations of traditional methods in handling the ambiguity of laser beam discrimination in transition regions, significantly improving the accuracy and consistency of water medium layer type identification. By introducing support calculation and a global hierarchical correction mechanism, this application can more accurately identify the boundaries between the clear liquid layer, the turbid transition layer, and the dense sediment layer. Especially when the medium distribution inside the sedimentation tank is complex or fluctuates, it can effectively avoid local misjudgments, ensuring the reliability and stability of the final sediment thickness determination. This correction method makes the entire detection process more robust to environmental noise and local anomalies, thus providing more accurate data support for the operation and management of wastewater sedimentation tanks.

[0062] Preferably, step B2 may include: B201. Each water-based medium layer is taken as the target medium layer in turn; B202. Multiply the matching degree between the target laser beam and the target medium layer by the first preset weight to obtain the support degree of the target laser beam for the target medium layer; B203. Multiply the matching degree between the laser beam adjacent above the target laser beam and the target medium layer by the second preset weight to obtain the support degree of the laser beam adjacent above the target laser beam for the target medium layer; B204. Multiply the matching degree between the laser beam adjacent to the target laser beam and the target medium layer by the third preset weight to obtain the support degree of the laser beam adjacent to the target laser beam for the target medium layer.

[0063] Specifically, when calculating the support of a target laser beam for a specific target medium layer, the matching degree of the target laser beam itself, as well as the matching degree of the laser beams adjacent to it above and below, are considered. A first preset weight is used to measure the contribution of the target laser beam's own matching degree to the target medium layer; a second preset weight is used to measure the contribution of the matching degree of the laser beam adjacent to it above; and a third preset weight is used to measure the contribution of the matching degree of the laser beam adjacent to it below. These preset weights are not fixed but dynamically adjusted according to the currently determined type of the target medium layer. For example, when the target medium layer is identified as a clear liquid layer, which is usually located in the upper part of the sedimentation tank, the area above it is more likely to belong to the clear liquid layer. Therefore, the support of the laser beam adjacent to it above should have a higher weight; that is, the second preset weight will be greater than the first preset weight, and the first preset weight will be greater than the third preset weight. When the target medium layer is a turbid transition layer, this layer typically has a certain thickness and its characteristics may be relatively uniform in the vertical direction. Therefore, the matching degree of the target laser beam itself should have the highest weight, while the matching degree of adjacent upper and lower laser beams should have relatively lower and equal weights. When the target medium layer is a dense sediment layer, this layer is usually located below. Therefore, the support of adjacent lower laser beams for the dense sediment layer should have a higher weight, that is, the third preset weight will be greater than the first preset weight, and the first preset weight will be greater than the second preset weight. In this way, the degree of support of laser beams at different locations for a specific water medium layer can be more accurately reflected.

[0064] This application's solution addresses the problem of insufficient correction accuracy caused by failing to fully consider the boundary characteristics of different media layers during the correction process for water media layer types. Specifically, when the target media layer is identified as a clear liquid layer, since the clear liquid layer is usually located at the top of the sedimentation tank, the area above it is more likely to belong to the clear liquid layer. Therefore, a higher second preset weight is assigned to the adjacent upper laser beam, which can more accurately confirm the boundary of the clear liquid layer. Conversely, when the target media layer is identified as a dense sediment layer, since the dense sediment layer is usually located at the bottom of the sedimentation tank, the area below it is more likely to belong to the dense sediment layer. Therefore, a higher third preset weight is assigned to the adjacent lower laser beam, which helps to more accurately identify the top boundary of the dense sediment layer. When the target medium layer is identified as a turbid transition layer, this layer is typically located between the clear liquid layer and the dense sediment layer, with a certain vertical range. In this case, the matching degree of the target laser beam itself has the most direct indicative effect on whether it belongs to the turbid transition layer. Therefore, it is assigned the highest value of the first preset weight. At the same time, the matching degree of the adjacent upper and lower laser beams also provides auxiliary information, but with relatively lower and equal weights to reflect its transitional nature. This mechanism of dynamically adjusting the weight based on the target medium layer type allows the support calculation to better adapt to the actual physical characteristics of water stratification, thereby improving the accuracy and robustness of water medium layer type identification.

[0065] Through the above technical solution, when correcting the water medium layer type of the laser beam in the transition region, the contribution of the matching degree of the target laser beam and its adjacent laser beams to the support can be adaptively adjusted according to the different characteristics of the target medium layer, thereby making the support calculation more refined and reasonable. This differentiated weight allocation mechanism effectively improves the identification accuracy of the boundary between the clear liquid layer, the turbid transition layer, and the dense sediment layer. Especially in the complex sedimentation tank water environment, it can significantly reduce the false judgment rate, improve the accuracy and stability of water medium layer type identification, and thus provide a more reliable basis for the subsequent accurate determination of sediment thickness.

[0066] In some implementations, step A5 includes: A501. Based on the water medium layer type discrimination result, identify the laser receiver corresponding to the first laser beam from top to bottom that is judged to be a dense sediment layer, and record it as the target laser receiver; A502. Obtain the height of the target laser receiver relative to the bottom of the sewage sedimentation tank, as the sediment thickness; A503. Issue a warning command when the sediment thickness exceeds the preset thickness threshold.

[0067] Specifically, in step A501, after obtaining the results of identifying the type of water medium layer currently traversed by each laser beam, it is necessary to identify the specific location of the sediment layer from these results. Here, "the first laser beam identified as a dense sediment layer from top to bottom" means that in the laser receiver array, starting from the topmost laser receiver and checking downwards sequentially, the laser beam corresponding to the first laser receiver detected to pass through the dense sediment layer is identified as the upper boundary of the sediment layer. The laser receiver corresponding to this laser beam is then marked as the target laser receiver. Dense sediment layers typically refer to the highly concentrated solid particle layer at the bottom of the sedimentation tank. Their optical characteristics differ significantly from the clear liquid layer and the turbid transition layer, thus allowing for accurate identification.

[0068] Further, in step A502, once the target laser receiver is identified, its height relative to the bottom of the wastewater sedimentation tank can be obtained. Since the target laser receiver represents the uppermost boundary of the dense sediment layer, this height value can be directly used as the thickness of the sediment in the current wastewater sedimentation tank. This height can be obtained through pre-calibration.

[0069] Furthermore, in step A503, to effectively manage and control the sediment thickness, real-time monitoring of the determined sediment thickness is required. When the acquired sediment thickness exceeds a preset thickness threshold, the system will automatically issue a warning command. This preset thickness threshold can be set according to factors such as the design capacity of the sedimentation tank, operating requirements, and maintenance cycle. The warning command can take various forms, such as audible and visual alarms, sending data signals to the control center, or triggering automatic sludge removal equipment. Its purpose is to remind operators to take timely measures to prevent excessive sediment accumulation from affecting the normal operating efficiency of the sedimentation tank or causing equipment damage.

[0070] This application's solution achieves precise quantification and intelligent alarm of sediment thickness by refining the results of water medium layer type identification. Specifically, by identifying the laser emitter corresponding to the first laser beam identified from top to bottom as a dense sediment layer, the upper surface of the sediment layer can be accurately located. This is because the laser receiver array (and laser emitter array) are arranged vertically, and each laser beam penetrates the water at different depths. When a laser beam first penetrates the dense sediment layer, its position represents the highest point of the sediment layer. Therefore, obtaining the height of the target laser receiver relative to the bottom of the sewage sedimentation tank can directly and accurately reflect the actual thickness of the sediment, avoiding estimation errors that may exist in traditional methods. Furthermore, by comparing the sediment thickness with a preset thickness threshold and issuing warning commands accordingly, the system can promptly detect excessive sediment accumulation, providing timely intervention signals to operators and effectively preventing problems such as decreased operating efficiency, accelerated equipment wear, and even system failure caused by excessive sediment accumulation.

[0071] Through the above technical solution, this application provides a more accurate, reliable, and automated mechanism for determining and controlling sediment thickness. Compared to basic solutions that only vaguely mention "determining sediment thickness and performing alarm control," this application clarifies the specific calculation method for sediment thickness, namely, by identifying the upper boundary of the dense sediment layer and obtaining its height, significantly improving the accuracy and operability of thickness determination. Simultaneously, the introduced preset thickness threshold and warning command mechanism make the management of sedimentation tanks more intelligent and proactive, effectively avoiding the adverse effects of excessive sediment accumulation on sedimentation tank operating efficiency and equipment lifespan, thereby reducing the frequency and labor intensity of manual inspections and improving the overall operating efficiency and safety of the wastewater treatment system.

[0072] refer to Figure 2 , Figure 3 This application provides a sediment thickness detection system for a sewage sedimentation tank, including a main controller 1, a laser emitter array 2, a laser receiver array 3, and an alarm device 4, wherein the laser emitter array 2, the laser receiver array 3, and the alarm device 4 are all electrically connected to the main controller 1. The laser emitter array 2 includes multiple laser emitters 201 arranged in the vertical direction, and the laser receiver array 3 includes multiple laser receivers 301 arranged in the vertical direction. Each laser receiver 301 includes a main photoelectric detection unit 302 arranged horizontally and coaxially with a laser emitter 201 and an auxiliary photoelectric detection unit 303 misaligned with the optical axis of the laser emitter 201. The main controller 1 is used to execute the steps of the sediment thickness detection method in the sewage sedimentation tank described above.

[0073] The main controller 1 is the core processing unit of the entire system. Its function is to receive optical signal data from the laser receiver array 3, execute complex signal processing algorithms, determine the type of water medium layer, and control the alarm device based on the determination result. As one implementation, the main controller 1 can be an industrial-grade programmable logic controller (PLC), which has good stability, anti-interference capability, and real-time performance, making it suitable for industrial environments. Alternatively, the main controller 1 can also be an embedded system, such as a control board based on a high-performance microprocessor (e.g., an ARM processor). This control board integrates data acquisition, processing, and communication modules, providing more flexible algorithm implementation and richer data interfaces. Furthermore, the main controller 1 can also be an industrial personal computer (IPC), which performs the above functions by running specially developed software programs. Its advantages include strong computing power, facilitating complex algorithm iteration and data visualization.

[0074] Alarm device 4 is used to issue warnings or control commands when the detected sediment thickness exceeds a preset threshold. As a simple implementation, alarm device 4 can be an audible and visual alarm, alerting on-site operators with an alarm sound and flashing lights. As a more advanced implementation, alarm device 4 can be a communication module, such as a GPRS / 4G module or an Ethernet module, capable of sending alarm information to a remote monitoring center or maintenance personnel via SMS, email, or network protocols. It can even be linked to actuators such as sludge pumps to achieve automated sludge discharge control.

[0075] The laser emitter array 2 and the laser receiver array 3 can be fixedly installed inside the sewage sedimentation tank 90, but this setup makes it inconvenient to clean the laser emitter array 2 and the laser receiver array 3.

[0076] In some preferred embodiments, the sediment thickness detection system for the sewage sedimentation tank further includes a swing frame 5, two light-transmitting protective shells 6, and a driving device 7. The two light-transmitting protective shells 6 are arranged parallel to each other and spaced apart on the swing frame 5. The driving device 7 is connected to one end of the swing frame 5. The laser emitter array 2 and the laser receiver array 3 are respectively arranged inside the two light-transmitting protective shells 6. The driving device 7 can drive the swing frame 5 to swing until the two light-transmitting protective shells 6 extend vertically into the sewage sedimentation tank 90, and can also drive the swing frame 5 to swing until the two light-transmitting protective shells 6 leave the sewage sedimentation tank 90.

[0077] Specifically, the pendulum frame 5 can be understood as a mechanical support structure designed to support and position the laser emitter array 2 and the laser receiver array 3, allowing them to swing. The two light-transmitting protective housings 6 respectively house the laser emitter array 2 and the laser receiver array 3, providing physical protection against direct impact and corrosion from solid particles in the wastewater. These housings can be made entirely of light-transmitting material or only at locations requiring light transmission (such as the emission position of the laser emitter 201 and the incident position of the laser receiver 301), using materials such as high-strength glass or transparent polymers to ensure the laser beam can penetrate without attenuation. The drive device 7 can be a motor, electric push rod, hydraulic cylinder, or pneumatic actuator, which, through its connection with the pendulum frame 5, provides the power required to swing the pendulum frame 5. When the drive device 7 drives the pendulum frame 5 to swing, the two light-transmitting protective housings 6 can enter or exit the wastewater sedimentation tank 90. ​​For example, Figure 2 During operation, the pendulum 5 swings to the 0° position (i.e., Figure 2 (in the middle position), at this time, the two light-transmitting protective shells 6 extend vertically into the sewage sedimentation tank 90. ​​When too much dirt film accumulates on the surface of the light-transmitting protective shells 6, the swing frame 5 can be driven to swing to a 180° position (for example, from the middle position). Figure 2 The current position is swung clockwise 180°, so that the two light-transmitting protective shells 6 are removed from the sewage sedimentation tank 90, so as to facilitate the cleaning of the light-transmitting protective shells 6.

[0078] This application's solution effectively solves the problems of decreased detection accuracy and maintenance difficulties caused by the accumulation of dirt film on the surface of optical devices by introducing a pendulum frame 5, a light-transmitting protective housing 6, and a driving device 7. Specifically, the laser emitter array 2 and the laser receiver array 3 are respectively installed in two light-transmitting protective housings 6. During normal operation, these housings are driven by the driving device 7 to swing the pendulum frame 5 vertically into the sewage sedimentation tank 90, allowing the laser beam to penetrate the sewage medium for sediment thickness detection. When the system detects severe dirt film accumulation on the surface of the optical device, or when regular maintenance is required, the driving device 7 will drive the pendulum frame 5 to swing, causing the two light-transmitting protective housings 6 to completely leave the sewage sedimentation tank 90 (therefore, after step A2, the above step A6 is also included: if the signal attenuation exceeds a preset attenuation threshold, a cleaning prompt signal is issued, and the driving device 7 is controlled to swing the pendulum frame 5 to the cleaning position). Thus, maintenance personnel can clean the surface of the light-transmitting protective housing 6 from the outside without entering the sewage sedimentation tank 90, thereby removing the dirt film and restoring the light transmission performance of the optical device.

[0079] Through the above technical solution, the sediment thickness detection system for wastewater sedimentation tanks of this application significantly improves the maintainability and operational reliability of the system. This solution avoids the complex and dangerous manual cleaning operations required by traditional detection systems after dirt accumulates on the surface of optical components, thereby reducing maintenance costs and safety risks. Furthermore, the ability to clean quickly and easily ensures that the optical components maintain good light transmission, thus guaranteeing the long-term accuracy and stability of sediment thickness detection and extending the service life of the equipment.

[0080] Furthermore, in actual operation, the pendulum frame 5 can be kept in a non-working position under normal conditions, that is, the position where the light-transmitting protective housing 6 is away from the sewage sedimentation tank 90 (such as the cleaning position), and periodically swing to the working position (that is, the position where the two light-transmitting protective housings 6 extend vertically into the sewage sedimentation tank 90) to detect the sediment thickness. This can reduce the contact time between the light-transmitting protective housing 6 and the sewage, delay the cleaning cycle, and reduce the cleaning frequency. Therefore, step A1 may include: periodically controlling the drive device 7 to swing the pendulum frame 5 to the working position according to a preset cycle, then using the laser emitter array 2 to emit a laser beam, and collecting the light signal intensity received by each laser receiver 301, and smoothing the light signal intensity to obtain a smoothed signal intensity.

[0081] In some embodiments, the sediment thickness detection system for the wastewater sedimentation tank also includes a support frame 8 disposed on the edge or inside the wastewater sedimentation tank 90, the support frame 8 being used to support the swing frame 5 when the swing frame 5 swings to the point where the two light-transmitting protective shells 6 extend vertically into the wastewater sedimentation tank 90.

[0082] This reduces the bending deformation of the pendulum frame 5 under gravity and allows for positioning of the pendulum frame 5, thereby better ensuring that the two light-transmitting protective shells 6 remain vertical and in the accurate working position, thus guaranteeing detection accuracy.

[0083] In some implementations, see Figure 2 The drive unit 7 and the main controller 1 are integrated into a control box 9 to effectively protect the drive unit 7 and the main controller 1.

[0084] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for detecting sediment thickness in a wastewater sedimentation tank, characterized in that, The thickness of sediment in a wastewater sedimentation tank is detected based on a laser emitter array and a laser receiver array. The laser emitter array includes multiple laser emitters arranged in a vertical direction, and the laser receiver array includes multiple laser receivers arranged in a vertical direction. Each laser receiver includes a main photoelectric detection unit that is horizontally coaxial with one of the laser emitters and an auxiliary photoelectric detection unit that is misaligned with the optical axis of the laser emitter. The method for detecting sediment thickness in the wastewater sedimentation tank includes: A1. A laser beam is emitted using a laser emitter array, and the intensity of the light signal received by each laser receiver is collected. The intensity of the light signal is then smoothed to obtain a smoothed signal intensity. A2. Based on the smoothed signal intensity of the laser receiver located in the clear liquid zone of the sedimentation tank, identify the signal attenuation caused by the accumulation of dirt film on the surface of the optical device, and use this information to compensate for all the smoothed signal intensities to obtain the compensated smoothed signal intensity. A3. Based on the compensated smooth signal intensity, determine the scattering ratio of each laser receiver and the signal intensity fluctuation index; the scattering ratio is the ratio between the main signal intensity and the auxiliary signal intensity, the main signal intensity is the compensated smooth signal intensity of the main photoelectric detection unit, and the auxiliary signal intensity is the compensated smooth signal intensity of the auxiliary photoelectric detection unit. A4. Based on the main signal intensity, the scattering ratio, and the signal intensity fluctuation index, determine the type of water medium layer that each laser beam is currently passing through; the water medium layer types include clear liquid layer, turbid transition layer, and dense sediment layer; A5. Based on the water medium layer type identification results, determine the sediment thickness and implement alarm control based on the sediment thickness.

2. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 1, characterized in that, Step A2 includes: A201. Within a preset time window, for the smoothed signal intensity of the laser receiver located in the clear liquid zone of the sedimentation tank, calculate the rate of decrease of the smoothed signal intensity and the fluctuation level of the smoothed signal intensity; A202. Based on the descent rate and the fluctuation level, determine whether the descent rate is lower than a preset rate threshold and whether the fluctuation level remains within a preset level range; A203. If the rate of decrease is lower than a preset rate threshold and the fluctuation level remains within a preset level range, it is determined that there is a dirt film accumulation on the surface of the optical device, and the current smooth signal intensity of the laser receiver in the sedimentation tank clear liquid area is compared with the preset reference signal intensity to obtain the signal attenuation caused by the dirt film accumulation; otherwise, the signal attenuation is set to zero. A204. Based on the signal attenuation amount, compensate for the strength of all the smoothed signals to obtain the compensated smoothed signal strength.

3. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 1, characterized in that, Step A3 includes the steps performed for each of the laser receivers: A301. Calculate the ratio between the main signal intensity and the auxiliary signal intensity of the laser receiver, and use it as the scattering ratio of the laser receiver; A302. Calculate the standard deviation of the main signal strength within a preset time window; A303. Calculate the instantaneous rate of change of the main signal strength at each moment within a preset time window; A304. Based on the instantaneous rate of change, identify instantaneous events with drastic changes in signal strength, and determine the average duration and frequency of occurrence of the instantaneous events; A305. The standard deviation, the instantaneous rate of change, the average duration, and the frequency of occurrence are used as the signal strength volatility indicators.

4. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 1, characterized in that, Step A4 includes: A401. Based on the main signal intensity, the scattering ratio, and the signal intensity fluctuation index, calculate the matching degree between each laser beam and the preset characteristic mode of the clear liquid layer, the turbid transition layer, and the dense sediment layer; A402. Based on the matching degree, the type of water medium layer that each laser beam is currently passing through is initially determined; A403. Based on the matching degree, identify the laser beam that simultaneously meets the preset matching degree range of the turbid transition layer and the dense sediment layer as the laser beam in the transition region; A404. The preliminary judgment result is corrected by combining the matching degree of the laser beams adjacent above and below the laser beam in the transition region.

5. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 4, characterized in that, Step A402 includes: For each laser beam, the matching degree between the laser beam and the preset characteristic patterns of the clear liquid layer, the turbid transition layer and the dense sediment layer is compared. The water medium layer type with the highest matching degree is selected as the preliminary judgment result of the water medium layer type currently being traversed by the laser beam.

6. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 4, characterized in that, Step A404 includes: B1. Each laser beam in the transition region is used as the target laser beam in turn; B2. Based on the self-matching degree of the target laser beam and the matching degree of the laser beams above and below it, calculate the support degree of the self-matching degree and the matching degree of the laser beams above and below it for the clear liquid layer, the turbid transition layer and the dense sediment layer respectively. B3. Based on the aforementioned support, calculate the total support for each of the clear liquid layer, the turbid transition layer, and the dense sediment layer; B4. Select the water medium layer type with the highest total support as the preliminary correction result for the water medium layer type currently traversed by the target laser beam; B5. After completing the initial correction of the water medium layer type of all laser beams in the transition zone, identify the laser beam with the highest position and the water medium layer type as a turbid transition layer as the first laser beam, and identify the laser beam with the lowest position and the water medium layer type as a turbid transition layer as the second laser beam. B6. Correct all water media layers currently traversed by laser beams higher than the first laser beam to clear liquid layers, correct all water media layers currently traversed by the first laser beam to turbid transition layers, and correct all water media layers currently traversed by laser beams lower than the second laser beam to dense sediment layers.

7. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 6, characterized in that, Step B2 includes: B201. Each water-based medium layer is taken as the target medium layer in turn; B202. Multiply the matching degree between the target laser beam and the target medium layer by the first preset weight to obtain the support degree of the target laser beam for the target medium layer; B203. Multiply the matching degree between the laser beam adjacent above the target laser beam and the target medium layer by the second preset weight to obtain the support degree of the laser beam adjacent above the target laser beam for the target medium layer; B204. Multiply the matching degree between the laser beam adjacent to the target laser beam and the target medium layer by the third preset weight to obtain the support degree of the laser beam adjacent to the target laser beam for the target medium layer.

8. The method for detecting sediment thickness in a wastewater sedimentation tank according to claim 1, characterized in that, Step A5 includes: A501. Based on the water medium layer type discrimination result, identify the laser receiver corresponding to the first laser beam from top to bottom that is judged to be a dense sediment layer, and record it as the target laser receiver; A502. Obtain the height of the target laser receiver relative to the bottom of the sewage sedimentation tank, as the sediment thickness; A503. When the thickness of the deposit exceeds a preset thickness threshold, a warning command is issued.

9. A sediment thickness detection system for a sewage sedimentation tank, characterized in that, It includes a main controller, a laser emitter array, a laser receiver array, and an alarm device, wherein the laser emitter array, the laser receiver array, and the alarm device are all electrically connected to the main controller; The laser emitter array includes multiple laser emitters arranged in a vertical direction, and the laser receiver array includes multiple laser receivers arranged in a vertical direction. Each laser receiver includes a main photoelectric detection unit that is horizontally coaxial with one of the laser emitters and an auxiliary photoelectric detection unit that is misaligned with the optical axis of the laser emitter. The main controller is used to execute the steps of the sediment thickness detection method for a sewage sedimentation tank according to any one of claims 1-8.

10. A sediment thickness detection system for a wastewater sedimentation tank according to claim 9, characterized in that, It also includes a pendulum frame, two light-transmitting protective housings, and a driving device. The two light-transmitting protective housings are arranged parallel to each other and spaced apart on the pendulum frame. The driving device is connected to one end of the pendulum frame. The laser emitter array and the laser receiver array are respectively arranged inside the two light-transmitting protective housings. The driving device can drive the pendulum frame to swing until the two light-transmitting protective housings extend vertically into the sewage sedimentation tank, and can also drive the pendulum frame to swing until the two light-transmitting protective housings leave the sewage sedimentation tank.

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