Sludge conditioning chemical dosing automatic control system based on bypass sensing signal feedback accurate execution

Abstract

The invention discloses a sludge conditioning dosing automatic control system based on bypass sensing signal feedback accurate execution, belongs to the technical field of environmental protection, and aims to solve the problems that real-time online monitoring and accurate control of sludge conditioning dosing are difficult, and the existing method is easily restricted by field operation conditions. According to the method, the bypass device is arranged beside the factory sludge main conditioning tank, and the optimal conditioning agent adding amount corresponding to the current sludge is determined and fed back to the factory sludge main conditioning tank according to the electrochemical parameter change of the sludge in the bypass device, so that the parallel development of the optimization process and the sludge feeding process is realized; therefore, on one hand, the sample signal acquisition uniformity is improved, on the other hand, the decision-making waiting time is shortened, and the dose judgment timeliness and accuracy are improved. The device is not influenced by field treatment scale, stirring efficiency and operation conditions, can realize unmanned real-time intelligent regulation and control of accurate dosing of sludge, is simple in equipment maintenance, and can better meet diversified and intelligent industrial production requirements.

Description

Technical Field

[0001] This invention relates to an automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution, belonging to the field of environmental protection technology. Background Technology

[0002] Rapid urban and industrial development has led to an increase in sludge production. Sludge is rich in water and requires dewatering to reduce its volume and meet the requirements of subsequent treatment and disposal. Conditioning is crucial in the sludge dewatering process, aiming to improve its dewatering performance and reduce the difficulty of subsequent treatment and disposal. In current sludge conditioning processes, determining the optimal dosage in real time and applying it intelligently and precisely is a key challenge. Traditional methods mostly rely on manual laboratory experiments, which are not only time-consuming and labor-intensive, but also difficult to accurately match the sludge properties in real time due to their complexity and variability, leading to problems of insufficient or excessive dosage. Insufficient dosage results in poor sludge conditioning and affects dewatering efficiency; excessive dosage increases reagent costs and may also cause subsequent treatment problems, such as filter cloth clogging, affecting the stable operation of the entire dewatering system.

[0003] Some existing dosing control methods attempt to address these issues to some extent. For example, application number 202311463574.8 discloses a sludge intelligent conditioning system with self-optimizing dosage, which uses an electrochemical impedance spectroscopy to perform real-time frequency scanning of the sludge to obtain electrochemical parameters and predicts the optimal dosage based on its changes. However, current methods still have limitations: firstly, the sample signal acquisition is uneven, constrained by the large scale of on-site processing and low stirring efficiency; secondly, the optimization decision requires waiting time, making it difficult to adapt to large-scale applications in actual production. To address this, this invention proposes setting up a bypass device next to the main sludge conditioning tank in the plant. Based on the changes in the electrochemical parameters of the sludge in the bypass device, the optimal conditioner dosage for the current sludge is determined and fed back to the main sludge conditioning tank, enabling the optimization process and the sludge feeding process to proceed in parallel. This improves the uniformity of sample signal acquisition, shortens the waiting time for optimization decisions, and enhances the timeliness and accuracy of dosage judgment, achieving a dual spatial and temporal reconstruction of the intelligent optimization process and overcoming the shortcomings of existing technologies. Summary of the Invention

[0004] This invention aims to provide an automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution. By setting up a bypass device next to the main sludge conditioning tank in the plant, the optimal dosage of conditioning agent for the current sludge is determined based on the changes in the electrochemical parameters of the sludge in the bypass device and fed back to the main sludge conditioning tank in the plant, thereby achieving precise execution of sludge conditioning and dosing.

[0005] This invention mainly includes: a main conditioning vessel, a bypass device, an electrochemical sensing module, a decision control module, and a dose feedback unit.

[0006] The specific steps for accurately executing automatic control of sludge conditioning dosing based on bypass sensing signal feedback are as follows:

[0007] A portion of the raw sludge in the main conditioning tank is introduced into the bypass device;

[0008] An electrochemical sensing probe performs frequency scanning tests on sludge samples in a bypass device while simultaneously adding reagents to the bypass device. During the reagent addition process, the data acquisition unit acquires the electrochemical parameters d of the sludge samples. s / f c Changes;

[0009] The decision control module executes an exploratory dosage intelligent optimization strategy based on changes in electrochemical parameters and the response model to determine the optimal conditioner dosage for the current sludge.

[0010] The dosage feedback unit is connected to the conditioning agent dosing control system of the main conditioning tank. It is used to feed back the optimization results of the bypass device to the main conditioning tank and implement conditioning agent dosing to complete the precise control of sludge dosing.

[0011] The above steps are then repeated cyclically to ensure the long-term operation of the system.

[0012] This invention replaces the traditional method of determining the optimal dosage by testing changes in the electrochemical parameters of sludge in the main conditioning tank in the self-optimization technology of dosage with a method performed in a bypass device. This solves the problems faced by performing the process in the main conditioning tank: (1) if the stirring time is too short, the optimal dosage cannot be accurately determined; if it is too long, the conditioning efficiency will decrease; (2) the operation of the electrochemical sensing module is easily affected by the material and size of the main conditioning tank, which can easily lead to inaccurate testing or even failure. By setting up a bypass device, the optimization process and the sludge feeding process can be carried out in parallel, which is conducive to improving the uniformity of sample signal acquisition, shortening the waiting time for optimization decisions, and improving the timeliness and accuracy of dosage judgment, thereby realizing the spatial and temporal reconstruction of the intelligent optimization process.

[0013] The bypass device includes: (1) a sludge sampling unit, which is connected to the bottom or middle of the main conditioning tank. The flow rate of the sludge sample entering the bypass device is adjusted by a flow control valve. The flow rate range is 0.1-10 L / h to ensure the synchronicity and representativeness of the sludge sample with the sludge in the main conditioning tank; (2) a stirring unit, which adopts magnetic stirring or mechanical stirring with a stirring rate of 50-500 r / min to ensure uniform mixing of the sludge sample in the bypass device and avoid local concentration differences from affecting the detection of electrochemical parameters; (3) a reagent dosing unit, which includes a metering pump and a reagent storage tank, for accurately adding conditioning agent into the bypass device; and (4) a venting unit, which is located at the bottom of the bypass device and controlled by a solenoid valve. After each batch of conditioning is completed, the unit automatically vents and cleans the internal cavity to avoid residual sludge from interfering with the detection of the next batch.

[0014] The electrochemical sensing probe has a time interval of 1s to 30min between two consecutive frequency scans, a sinusoidal voltage range of 1 to 1000mV applied during the frequency scan, and a scan frequency range of 0.1Hz to 10MHz.

[0015] The electrochemical sensing probe is installed inside the bypass device and acquires the electrochemical parameters ds / fc of the sludge sample through real-time scanning. These parameters are collected by the data acquisition unit. The calculation of ds / fc includes the following steps:

[0016] (1) No special treatment is required for the sludge sample during the test. The electrochemical sensing probe is inserted into the sludge to be tested for frequency scanning to obtain the real part, imaginary part and complex impedance modulus of the sludge. The complex impedance modulus is then corrected. The correction method is that the corrected complex impedance modulus is equal to the complex impedance modulus corresponding to each scanning frequency minus the complex impedance modulus at the highest frequency.

[0017] (2) Calculate the critical frequency fc at which the corrected complex impedance modulus changes abruptly. The method is as follows: The critical frequency is the frequency point at which the logarithm of the corrected complex impedance modulus changes from approximately constant to decreasing with increasing logarithm of frequency. The calculation formula is:

[0018]

[0019] In the formula, f c R is the critical frequency at which the complex impedance modulus changes abruptly. t and C p These are the charge transfer resistance and double-layer capacitance at the interface of the sludge flocs, respectively, and their values ​​are represented by R. t and C p The parallel circuit is connected in series with the charge transfer resistance R of the sludge suspension. c Obtaining the real and imaginary parts of the equivalent circuit fitting impedance;

[0020] (3) Using the critical frequency and its corresponding corrected complex impedance modulus as the starting point, perform an inverse Fourier transform on the frequency-corrected complex impedance modulus curve to obtain the transformed time domain and the amplitude of the impedance signal.

[0021] (4) Perform a Fourier transform on the obtained time-domain-impedance signal amplitude curve to obtain the frequency domain and the square of the impedance signal amplitude. The scale-free model of the frequency and the square of the impedance signal amplitude is as follows:

[0022]

[0023] In the formula, P is the square of the impedance signal amplitude, f is the scanning frequency after inverse Fourier transform and Fourier transform, and d s Let be the spectral dimension of the trajectory of the electric charge.

[0024] (5) The spectral dimension d of the charge trajectory is calculated based on the scale-free model of frequency and the square of impedance signal amplitude. s The calculation method is as follows: plot the logarithm of the square of the impedance signal amplitude P on the Y-axis and the logarithm of the scanning frequency f after inverse Fourier transform and Fourier transform on the X-axis. Fit the plot with linear regression analysis, and substitute the obtained slope into the scale-free model between P and f to obtain d. s ;

[0025] (6) Use the obtained d s Divide by the critical frequency f c , to obtain d s / f c .

[0026] The decision control module executes a trial-and-error dosage intelligent optimization strategy based on the changes in the electrochemical parameter ds / fc and the response model to determine the optimal conditioner dosage for the current sludge, including:

[0027] (1) According to d s / f c The dynamic changes are calculated to determine the difference between the administered dosage and the optimal dosage, and the dosage is controlled to gradually bring the administered dosage closer to the optimal dosage. The specific steps are as follows:

[0028] The sludge was subjected to frequency scanning tests using an electrochemical impedance spectroscopy instrument connected to conductivity electrodes to extract d s / f c The value is recorded as P1. After P1 is detected, the control system turns on the dosing pump and adds the first stage dosage a0. The value of a0 is 0.001 mg / g dry mud to 100 mg / g dry mud. After the stage dosage is reached, the dosing pump is turned off.

[0029] The electrochemical impedance spectroscopy performed a second frequency scan to extract d s / fc The value is denoted as P2, and the electrochemical parameter d is calculated. s / f c The slope of the change is calculated using the following formula:

[0030]

[0031] In the formula, Y2′ represents the electrochemical parameter d after the second frequency scan. s / f c The slope of the change is detected. After P2 is detected, the control system turns on the dosing pump to add the second-stage dosage a1, where a1 ranges from 0.001 mg / g dry sludge to 100 mg / g dry sludge. After reaching the second-stage dosage, the dosing pump is turned off, and the cumulative dosage a2 is recorded. The calculation formula is:

[0032] a2=a0+a1

[0033] The electrochemical impedance spectroscopy performed a third frequency scan, extracted the ds / fc value, denoted as P3, and calculated the slope of the change in the electrochemical parameter ds / fc. The calculation formula is as follows:

[0034]

[0035] In the formula, Y3′ represents the electrochemical parameter d after the third frequency scan. s / f c The slope of the change is used to calculate the difference X3 between the current dosage and the optimal dosage based on Y3′. The calculation formula is:

[0036]

[0037] In the formula, B, C, and q are calculation coefficients. The value range of B is -0.05 to 0.1, the value range of C is -0.05 to 0.1, and the value range of q is 0.1 to 5. After X3 is detected, the control system turns on the dosing pump to add the third-stage dosage X3. After reaching the third-stage dosage, the dosing pump is turned off, and the cumulative dosage a3 after the third-stage dosing is completed is recorded.

[0038] a3=x3+a2

[0039] The electrochemical impedance spectroscopy performed a fourth frequency scan to extract d s / f c The value is denoted as P4, and the electrochemical parameter d is calculated. s / f c The slope of the change is calculated using the following formula:

[0040]

[0041] In the formula, Y4′ represents the electrochemical parameter d after the fourth frequency scan. s / fc The slope of the change is used to determine whether the absolute value of Y4′ is within the range of 0.001–0.5.

[0042] ① If so, calculate the difference X4 between the current dosage and the optimal dosage. The formula is:

[0043]

[0044] In the formula, B and C are calculation coefficients. The value range of B is -0.05 to 0.1, and the value range of C is -0.05 to 0.1. After X4 is detected, the control system turns on the dosing pump and adds the fourth stage drug dosage X4. After the fourth stage drug dosage is reached, the dosing pump is turned off and the drug dosing ends.

[0045] ② If not, calculate the difference X4 between the current dosage and the possible optimal dosage. The formula is:

[0046]

[0047] In the formula, B, C, and q are calculation coefficients. The value range of B is -0.05 to 0.1, the value range of C is -0.05 to 0.1, and the value range of q is 0.1 to 5. After X4 is detected, the control system turns on the dosing pump to add the fourth-stage dosage X4. After reaching the fourth-stage dosage, the dosing pump is turned off, and the cumulative dosage a4 after the fourth-stage dosing is completed is recorded.

[0048] a4 = x4 + a3

[0049] Subsequently, the electrochemical impedance spectroscopy continued frequency scanning, extracted the ds / fc value, and further calculated the slope of the change in the electrochemical parameter ds / fc. The calculation formula is as follows:

[0050]

[0051] In the formula, Y′ n and Y′ n-1 Electrochemical parameters d after the nth and (n-1)th frequency scans, respectively. s / f c The slope of change, P n and P n-1 d were obtained from the nth and (n-1)th frequency scans of the electrochemical impedance spectroscopy, respectively. s / f c Value, a n-1 and a n- 2 represents the cumulative dosage after the completion of the (n-1)th and (n-2)th stages of drug administration, respectively. If Y′ n If the absolute value is in the range of 0.001–0.5, calculate the difference X between the current dosage and the possible optimal dosage. nThe calculation formula is:

[0052]

[0053] In the formula, B and C are calculation coefficients, with B ranging from -0.05 to 0.1 and C ranging from -0.05 to 0.1. After detecting Xn, the control system turns on the dosing pump to add the nth stage dosage Xn. After reaching the nth stage dosage, the dosing pump is turned off, and the dosing ends. If the absolute value of Y′n is not within the range of 0.001 to 0.5, the difference Xn between the dosage already added and the optimal dosage is calculated using the following formula:

[0054]

[0055] In the formula, B, C, and q are calculation coefficients, with B ranging from -0.05 to 0.1, C ranging from -0.05 to 0.1, and q ranging from 0.1 to 5. X is detected. n Then, the control system activates the dosing pump to administer the dosage X for the nth stage of the drug. n After reaching the dosage for stage n, turn off the dosing pump and record the cumulative dosage a after completing stage n. n :

[0056] a n =x n +a n-1

[0057] Subsequently, the electrochemical impedance spectroscopy continued frequency scanning until the electrochemical parameter d was obtained after the nth frequency scan. s / f c The absolute value of the slope of change is in the range of 0.001–0.5;

[0058] (2) Predicting drug dosage based on mathematical regression models. The mathematical regression models used include multinomial regression, linear regression, and logistic regression. The steps for predicting the optimal drug dosage based on the multinomial regression model are as follows:

[0059] The electrochemical sensing probe was used to perform frequency scanning tests on the sludge, and d was extracted. s / f c The value is recorded as W1. After W1 is detected, the control system turns on the dosing pump to add 1-10 mg / g of agent to the dry mud, and then turns off the dosing pump.

[0060] Repeat the above operation n times, where n should be greater than 3, to obtain W1, W2, W3, W4, ..., W n Local multinomial regression (Lowess method) is used to smooth the data. The calculation formula is as follows:

[0061]

[0062] In the formula, y i ' is the smoothed value of the i-th data point; x i and y i These are the independent and dependent variable values ​​for the i-th data point, respectively; n is the total number of data points; K is the kernel function; b n It is the bandwidth, usually chosen as a certain proportion of the data range, which controls the smoothness of the local polynomial regression.

[0063] Perform polynomial fitting on the smoothed data, and calculate the derivative of the polynomial within a certain range. Based on the derivative value falling within a certain interval, find the derivative value and its corresponding coordinates that first appear within that interval.

[0064] ①If the derivative value is in the range of -0.001 to 0.001, the optimal amount of coagulant to be added is the coordinate value corresponding to the derivative value that first appears in this range;

[0065] ② If the derivative value is not in the range of -0.001 to 0.001, then continue to find the corresponding coordinate value of the derivative value that first appears in the range of -0.05 to 0.05. The corresponding coordinate value at this time is the optimal amount of coagulant to be added.

[0066] (3) Automatic optimization of dosing rate based on Ardunio development board control, according to sludge electrochemical parameters d during the dosing process. s / f c The dynamic changes in the drug dosage are monitored, and it is determined in real time whether the dosage is at the optimal level. The steps are as follows:

[0067] The sludge was subjected to frequency scanning tests using an electrochemical impedance spectroscopy instrument connected to a conductivity electrode probe, and d was extracted. s / f c The value is recorded as X1. After X1 is detected, the control system turns on the dosing pump and adds a certain dosage of medicine a0. The value of a0 is 1mg / g dry mud to 5mg / g dry mud. The dosing is set to end within 10 seconds and then the dosing pump is turned off.

[0068] The above operation was repeated six times to obtain X1, X2, X3, X4, X5, and X6. The data were smoothed using a Savitzky-Golay filter, and then the electrochemical parameter d was calculated. s / f c The rate of change is calculated using the following formula:

[0069]

[0070] In the formula, The smoothing coefficients are obtained by fitting the polynomial using the least squares method.

[0071] The formula for calculating the slope is:

[0072]

[0073] In the formula, h is the interval between adjacent points;

[0074] Using the method described above, the slope Y1' of X6 is calculated. It is then determined whether the value of Y1' falls within the range of -0.001 to 0.001.

[0075] ①If it is in the state, stop the drug administration, record the number of times the drug was administered at this time as n1, and the total amount of drug administered as a0n1 mg / g dry mud;

[0076] ② If not, continue adding a certain dosage of drug a0, and finish the dosing within 10 seconds. Then turn off the dosing pump, and use the electrochemical impedance spectroscopy of the conductivity electrode probe to perform the seventh frequency scan test on the sludge, extracting d. s / f c The value was denoted as X7, and the data was further smoothed using a Savitzky-Golay filter before calculating the electrochemical parameter d. s / f c The rate of change;

[0077] If the slopes obtained in the first n-1 scans are not within the range of -0.001 to 0.001, repeat the above operation until the electrochemical parameter d is obtained after the nth frequency scan. s / f c The absolute value of the slope of change is less than 0.001, and the cumulative dosage is finally obtained, which is calculated as follows:

[0078] a n =na0 mg / g dry mud

[0079] Among them, a n This represents the cumulative amount added.

[0080] The dosage feedback unit is connected to the conditioning agent dosing control system of the main conditioning tank, receives the optimal conditioning agent dosing command signal output by the decision control module, and feeds back the optimization results of the bypass device to the main conditioning tank and implements conditioning agent dosing. The transmission of the command signal adopts a hybrid transmission architecture combining wired and wireless transmission, which can synchronize the optimization results of the bypass device to the dosing control system of the main conditioning tank in a dynamic correction manner, realize the millisecond-level response adjustment of the agent dosing in the main conditioning tank, and ensure that the spatiotemporal matching degree between the bypass optimization results and the actual dosing in the main tank is ≥95%, thereby supporting the accurate execution of the system when the sludge feeding process and the optimization process are carried out in parallel.

[0081] The types of sludge include municipal waste sludge, digested sludge, industrial wastewater sludge, river and lake sediment, pipeline sediment, fecal sludge, organic biogas residue, and pharmaceutical residue. Preferably, the sludge concentration ranges from 1 to 100 g / L.

[0082] The reagents include, but are not limited to, polyaluminum chloride, aluminum chloride and its hydrates, aluminum salts and their hydrates, polyacrylamide, Fenton's reagent, ferric salts and their hydrates, ferrous salts and their hydrates, polyferric sulfate, manganese salts and their hydrates, titanium salts and their hydrates, magnesium salts and their hydrates, calcium salts and their hydrates, etc.

[0083] The beneficial effects of this invention are as follows:

[0084] Precise control of dosage. The optimal dosage is measured in real time by a bypass device and fed back to the main conditioning tank, which can precisely control the dosage, avoid underdosing or overdosing, and improve the sludge conditioning effect.

[0085] Highly adaptable. It can track changes in sludge properties in real time through a bypass device, and adjust the dosage according to the dynamic optimal dosing point to adapt to the needs of different sludge types, production scales, and operating conditions.

[0086] High cost-effectiveness. Precise dosing reduces pesticide waste and costs, while improving the operational stability of the dehydration system and reducing equipment failures and maintenance costs caused by improper dosing. Attached Figure Description

[0087] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0088] Appendix Figure 1 This is a schematic diagram of the process described in this invention. Detailed Implementation

[0089] Exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention. The following embodiments are only some embodiments of the present invention. Any simple modifications and improvements based on the technical concept of the present invention, without departing from the core technical solution of the present invention, should fall within the protection scope of the present invention.

[0090] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0091] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0092] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0093] The use of a sludge dosing precision control system based on bypass monitoring for conditioning dosing includes the following aspects and steps:

[0094] A portion of the raw sludge from the main conditioning tank is introduced into the bypass device; an electrochemical sensing probe performs frequency scanning tests on the sludge sample in the bypass device, while reagents are simultaneously added to the bypass device. During the reagent addition process, the data acquisition unit acquires the electrochemical parameters d of the sludge sample. s / f c The decision control module executes an exploratory dosage intelligent optimization strategy based on the changes in electrochemical parameters and the response model to determine the optimal conditioner dosage for the current sludge. The dosage feedback unit is connected to the conditioner dosing control system of the main conditioner tank and is used to feed back the optimization results of the bypass device to the main conditioner tank and implement conditioner dosing, thus completing the precise control of sludge dosing. The above steps are then repeated cyclically to achieve long-term operation of the system.

[0095] The present invention will be further illustrated by the following embodiments:

[0096] Example 1:

[0097] The residual sludge used in this embodiment of the invention is sludge from a wastewater treatment plant 1 in Beijing, with a sludge concentration of 11 g / L. The sludge conditioning process in this procedure runs continuously. The scanning parameters of the electrochemical impedance spectroscopy were set as follows: sinusoidal voltage range of 1–1000 mV, scanning frequency range of 1 Hz–10 MHz, and a time interval of 1 minute between two adjacent frequency scans. The flocculant used in the bypass device was polyaluminum chloride with a concentration of 10 g / L, consistent with the type and concentration of the agent used in the main conditioning tank. The sludge dewatering performance conditioned using the bypass monitoring-based precise sludge dosing control system of this invention is almost identical to that of manual dosing. The optimal dosing amount determined by this system is 5.18–5.26 g / gTSS, less than the fixed manual dosing amount of 6 g / gTSS. After one week of operation and monitoring, it was found that the reagent cost was reduced by 15%, the operational stability of the dewatering system was significantly improved, and the frequency of problems such as filter cloth clogging was greatly reduced, effectively improving the overall effect and economic benefits of sludge treatment.

[0098] Example 2:

[0099] In this embodiment of the invention, the residual sludge used was from a wastewater treatment plant 2 in Beijing, with a sludge concentration of 12.56 g / L. The sludge conditioning program was run continuously. In this embodiment, the scanning parameters of the electrochemical impedance spectroscopy were set to a sinusoidal voltage range of 1–1000 mV, a scanning frequency range of 1 Hz–10 MHz, and a time interval of 1 min between two adjacent frequency scans. The flocculant used in the bypass device was an organic flocculant from the same source as that used in the main process, a 5% polyacrylamide working solution. The sludge dosing precision control system based on bypass monitoring of this invention was used to control the sludge dewatering performance at the level of manual dosing. The optimal dosage determined by this system was 0.1 ± 0.02 g / gTSS, while the fixed manual dosage was 0.1 g / gTSS. After 30 days of operation and monitoring, it was found that the reagent cost was reduced by 10%, the operational stability of the dewatering system was significantly improved, and the entire process required no human intervention, indicating that this system can intelligently condition the sludge to its optimal dewatering state.

[0100] Example 3:

[0101] This embodiment of the invention uses dredged river sediment from a certain city, with chemicals added to the sludge conditioning tank, and the program runs continuously. In this embodiment, the scanning parameters of the electrochemical impedance spectroscopy are set as follows: sinusoidal voltage range of 1-1000mV, scanning frequency range of 1Hz-10MHz, and a time interval of 5 minutes between two adjacent frequency scans. The flocculants used in the bypass device are organic and inorganic flocculants from the same source as those in the main process, consisting of a 5% polyacrylamide working solution and a 20g / L polyaluminum chloride solution. Using the bypass monitoring-based sludge dosing precision control system of this invention, the sludge dewatering performance is controlled at the level of manual dosing. The optimal dosage determined by this system is 0.05±0.01g / gTSS polyacrylamide and 5±0.5g / gTSS polyaluminum chloride, respectively, while the fixed manual dosing amounts are 0.05g / gTSS polyacrylamide and 5g / gTSS polyaluminum chloride. After 30 days of operation and monitoring, it was found that the cost of the reagents was reduced by 12%, the system operated stably without human intervention, indicating that the system can intelligently adjust the sludge to the optimal state of dewatering.

Claims

1. An automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution, characterized in that, include: (1) Main conditioning tank, used to receive raw sludge and mix and condition it; (2) A bypass device is connected to the main conditioning tank to form a communicating vessel structure, used to synchronously introduce a portion of the sludge sample. The bypass device has a closed or semi-closed structure and its internal space is smaller than that of the main conditioning tank. (3) An electrochemical sensing module, including an electrochemical sensing probe and a data acquisition unit, wherein the electrochemical sensing probe is installed inside the bypass device and is used to acquire the electrochemical parameters of the sludge sample in real time. (4) Decision control module, connected to the electrochemical sensing module, is used to execute a trial dosage intelligent optimization strategy based on the changes in the electrochemical parameters and the response model to determine the optimal conditioner dosage for the current sludge. (5) Dosage feedback unit, connected to the conditioning agent dosing control system of the main conditioning tank, used to feed back to the main conditioning tank based on the optimization results of the bypass device and implement conditioning agent dosing; The sludge conditioning and dosing automatic control system based on bypass sensing signal feedback can perform intelligent probing and dosing optimization in the bypass device before the sludge feeding into the main conditioning tank is completed. This allows the optimization process and the sludge feeding process to be carried out in parallel, thereby improving the uniformity of sample signal acquisition, shortening the waiting time for optimization decisions, and improving the timeliness and accuracy of dosage judgment. This achieves a dual spatial and temporal reconstruction of the intelligent optimization process.

2. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The bypass device includes: (1) Sludge sampling unit, connected to the bottom or middle of the main conditioning tank, the flow rate of sludge sample entering the bypass device is adjusted by the flow control valve, the flow rate range is 0.1-10L / h, to ensure the synchronicity and representativeness of sludge sample with sludge in the main conditioning tank; (2) Stirring unit, using magnetic stirring or mechanical stirring, with a stirring rate of 50-500 r / min, to ensure uniform mixing of sludge samples in the bypass device and avoid local concentration differences affecting the detection of electrochemical parameters; (3) A dosing unit, including a metering pump and a dosing tank, is used to precisely add conditioning agent into the bypass device; (4) Venting unit, located at the bottom of the bypass device, is controlled by a solenoid valve. After each batch of conditioning is completed, it automatically vents and cleans the internal cavity to avoid residual sludge interfering with the testing of the next batch.

3. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The sinusoidal voltage applied during the frequency scanning process of the electrochemical sensing probe ranges from 1 to 1000 mV, and the scanning frequency ranges from 0.1 Hz to 10 MHz.

4. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The time interval between two consecutive frequency scans performed by the electrochemical sensing probe is 1 second to 30 minutes.

5. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The electrochemical sensing probe is installed inside the bypass device and acquires the electrochemical parameters ds / fc of the sludge sample through real-time scanning. These parameters are collected by the data acquisition unit. The calculation of ds / fc includes the following steps: (1) No special treatment is required for the sludge sample during the test. The electrochemical sensing probe is inserted into the sludge to be tested for frequency scanning to obtain the real part, imaginary part and complex impedance modulus of the sludge. The complex impedance modulus is then corrected. The correction method is that the corrected complex impedance modulus is equal to the complex impedance modulus corresponding to each scanning frequency minus the complex impedance modulus at the highest frequency. (2) Calculate the critical frequency fc at which the corrected complex impedance modulus changes abruptly. The method is as follows: The critical frequency is the frequency point at which the logarithm of the corrected complex impedance modulus changes from approximately constant to decreasing with increasing logarithm of frequency. The calculation formula is: In the formula, f c R is the critical frequency at which the complex impedance modulus changes abruptly. t and C p These are the charge transfer resistance and double-layer capacitance at the interface of the sludge flocs, respectively, and their values ​​are represented by R. t and C p The parallel circuit is connected in series with the charge transfer resistance R of the sludge suspension. c Obtaining the real and imaginary parts of the equivalent circuit fitting impedance; (3) Using the critical frequency and its corresponding corrected complex impedance modulus as the starting point, perform an inverse Fourier transform on the frequency-corrected complex impedance modulus curve to obtain the transformed time domain and the amplitude of the impedance signal. (4) Perform a Fourier transform on the obtained time-domain-impedance signal amplitude curve to obtain the frequency domain and the square of the impedance signal amplitude. The scale-free model of the frequency and the square of the impedance signal amplitude is as follows: In the formula, P is the square of the impedance signal amplitude, f is the scanning frequency after inverse Fourier transform and Fourier transform, and d s Let be the spectral dimension of the trajectory of the charge. (5) The spectral dimension d of the charge trajectory is calculated based on the scale-free model of frequency and the square of impedance signal amplitude. s The calculation method is as follows: plot the logarithm of the square of the impedance signal amplitude P on the Y-axis and the logarithm of the scanning frequency f after inverse Fourier transform and Fourier transform on the X-axis. Fit the plot with linear regression analysis, and substitute the obtained slope into the scale-free model between P and f to obtain d. s ; (6) Use the obtained d s Divide by the critical frequency f c , to obtain d s / f c .

6. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The decision control module executes a trial-and-error dosage intelligent optimization strategy based on the changes in the electrochemical parameter ds / fc and the response model to determine the optimal conditioner dosage for the current sludge, including: (1) According to d s / f c The dynamic changes are calculated to determine the difference between the administered dosage and the optimal dosage, and the dosage is controlled to gradually bring the administered dosage closer to the optimal dosage. The specific steps are as follows: The sludge was subjected to frequency scanning tests using an electrochemical impedance spectroscopy instrument connected to conductivity electrodes to extract d s / f c The value is recorded as P1. After P1 is detected, the control system turns on the dosing pump and adds the first stage dosage a0. The value of a0 is 0.001 mg / g dry mud to 100 mg / g dry mud. After the stage dosage is reached, the dosing pump is turned off. The electrochemical impedance spectroscopy performed a second frequency scan to extract d s / f c The value is denoted as P2, and the electrochemical parameter d is calculated. s / f c The slope of the change is calculated using the following formula: In the formula, Y2′ represents the electrochemical parameter d after the second frequency scan. s / f c The slope of the change is detected. After P2 is detected, the control system turns on the dosing pump to add the second-stage dosage a1, where a1 ranges from 0.001 mg / g dry sludge to 100 mg / g dry sludge. After reaching the second-stage dosage, the dosing pump is turned off, and the cumulative dosage a2 is recorded. The calculation formula is: a2=a0+a1 The electrochemical impedance spectroscopy performed a third frequency scan, extracted the ds / fc value, denoted as P3, and calculated the slope of the change in the electrochemical parameter ds / fc. The calculation formula is as follows: In the formula, Y3′ represents the electrochemical parameter d after the third frequency scan. s / f c The slope of the change is used to calculate the difference X3 between the current dosage and the optimal dosage based on Y3′. The calculation formula is: In the formula, B, C, and q are calculation coefficients. The value range of B is -0.05 to 0.1, the value range of C is -0.05 to 0.1, and the value range of q is 0.1 to 5. After X3 is detected, the control system turns on the dosing pump to add the third-stage dosage X3. After reaching the third-stage dosage, the dosing pump is turned off, and the cumulative dosage a3 after the third-stage dosing is completed is recorded. a3=x3+a2 The electrochemical impedance spectroscopy performed a fourth frequency scan to extract d s / f c The value is denoted as P4, and the electrochemical parameter d is calculated. s / f c The slope of the change is calculated using the following formula: In the formula, Y4′ represents the electrochemical parameter d after the fourth frequency scan. s / f c The slope of the change is used to determine whether the absolute value of Y4′ is within the range of 0.001–0.

5. ① If so, calculate the difference X4 between the current dosage and the optimal dosage. The formula is: In the formula, B and C are calculation coefficients. The value range of B is -0.05 to 0.1, and the value range of C is -0.05 to 0.

1. After X4 is detected, the control system turns on the dosing pump and adds the fourth stage drug dosage X4. After the fourth stage drug dosage is reached, the dosing pump is turned off and the drug dosing ends. ② If not, calculate the difference X4 between the current dosage and the possible optimal dosage. The formula is: In the formula, B, C, and q are calculation coefficients. The value range of B is -0.05 to 0.1, the value range of C is -0.05 to 0.1, and the value range of q is 0.1 to 5. After X4 is detected, the control system turns on the dosing pump to add the fourth-stage dosage X4. After reaching the fourth-stage dosage, the dosing pump is turned off, and the cumulative dosage a4 after the fourth-stage dosing is completed is recorded. a4 = x4 + a3 Subsequently, the electrochemical impedance spectroscopy continued frequency scanning, extracted the ds / fc value, and further calculated the slope of the change in the electrochemical parameter ds / fc. The calculation formula is as follows: In the formula, Y′ n and Y′ n-1 Electrochemical parameters d after the nth and (n-1)th frequency scans, respectively. s / f c The slope of change, P n and P n-1 d were obtained from the nth and (n-1)th frequency scans of the electrochemical impedance spectroscopy, respectively. s / f c Value, a n-1 and a n- 2 represents the cumulative dosage after the completion of the (n-1)th and (n-2)th stages of drug administration, respectively. If Y′ n If the absolute value is in the range of 0.001–0.5, calculate the difference X between the current dosage and the possible optimal dosage. n The calculation formula is: In the formula, B and C are calculation coefficients, with B ranging from -0.05 to 0.1 and C ranging from -0.05 to 0.

1. After detecting Xn, the control system turns on the dosing pump to add the nth stage dosage Xn. After reaching the nth stage dosage, the dosing pump is turned off, and the dosing ends. If the absolute value of Y′n is not within the range of 0.001 to 0.5, the difference Xn between the dosage already added and the optimal dosage is calculated using the following formula: In the formula, B, C, and q are calculation coefficients, with B ranging from -0.05 to 0.1, C ranging from -0.05 to 0.1, and q ranging from 0.1 to 5. X is detected. n Then, the control system activates the dosing pump to administer the dosage X for the nth stage of the drug. n After reaching the dosage for stage n, turn off the dosing pump and record the cumulative dosage a after completing stage n. n : a n =x n +a n-1 Subsequently, the electrochemical impedance spectroscopy continued frequency scanning until the electrochemical parameter d was obtained after the nth frequency scan. s / f c The absolute value of the slope of change is in the range of 0.001–0.5; (2) Predicting drug dosage based on mathematical regression models. The mathematical regression models used include multinomial regression, linear regression, and logistic regression. The steps for predicting the optimal drug dosage based on the multinomial regression model are as follows: The electrochemical sensing probe was used to perform frequency scanning tests on the sludge, and d was extracted. s / f c The value is recorded as W1. After W1 is detected, the control system turns on the dosing pump to add 1-10 mg / g of agent to the dry mud, and then turns off the dosing pump. Repeat the above operation n times, where n should be greater than 3, to obtain W1, W2, W3, W4, ..., W n Local multinomial regression (Lowess method) is used to smooth the data. The calculation formula is as follows: In the formula, y i ' is the smoothed value of the i-th data point; x i and y i These are the independent and dependent variable values ​​for the i-th data point, respectively; n is the total number of data points; K is the kernel function; b n It is the bandwidth, usually chosen as a certain proportion of the data range, which controls the smoothness of the local polynomial regression. Perform polynomial fitting on the smoothed data, and calculate the derivative of the polynomial within a certain range. Based on the derivative value falling within a certain interval, find the derivative value and its corresponding coordinates that first appear within that interval. ①If the derivative value is in the range of -0.001 to 0.001, the optimal amount of coagulant to be added is the coordinate value corresponding to the derivative value that first appears in this range; ② If the derivative value is not in the range of -0.001 to 0.001, then continue to find the corresponding coordinate value of the derivative value that first appears in the range of -0.05 to 0.

05. The corresponding coordinate value at this time is the optimal amount of coagulant to be added. (3) Automatic optimization of dosing rate based on Ardunio development board control, according to sludge electrochemical parameters d during the dosing process. s / f c The dynamic changes in the drug dosage are monitored, and it is determined in real time whether the dosage is at the optimal level. The steps are as follows: The sludge was subjected to frequency scanning tests using an electrochemical impedance spectroscopy instrument connected to a conductivity electrode probe, and d was extracted. s / f c The value is recorded as X1. After X1 is detected, the control system turns on the dosing pump and adds a certain dosage of medicine a0. The value of a0 is 1mg / g dry mud to 5mg / g dry mud. The dosing is set to end within 10 seconds and then the dosing pump is turned off. The above operation was repeated six times to obtain X1, X2, X3, X4, X5, and X6. The data were smoothed using a Savitzky-Golay filter, and then the electrochemical parameter d was calculated. s / f c The rate of change is calculated using the following formula: In the formula, The smoothing coefficients are obtained by fitting the polynomial using the least squares method. The formula for calculating the slope is: In the formula, h is the interval between adjacent points; Using the method described above, the slope Y1' of X6 is calculated. It is then determined whether the value of Y1' falls within the range of -0.001 to 0.

001. ①If it is in the state, stop the drug administration, record the number of times the drug was administered at this time as n1, and the total amount of drug administered as a0n1 mg / g dry mud; ② If not, continue adding a certain dosage of drug a0, and finish the dosing within 10 seconds. Then turn off the dosing pump, and use the electrochemical impedance spectroscopy of the conductivity electrode probe to perform the seventh frequency scan test on the sludge, extracting d. s / f c The value was denoted as X7, and the data was further smoothed using a Savitzky-Golay filter before calculating the electrochemical parameter d. s / f c The rate of change; If the slopes obtained in the first n-1 scans are not within the range of -0.001 to 0.001, repeat the above operation until the electrochemical parameter d is obtained after the nth frequency scan. s / f c The absolute value of the slope of change is less than 0.001, and the cumulative dosage is finally obtained, which is calculated as follows: a n =na0 mg / g dry mud Among them, a n This represents the cumulative amount added.

7. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The dosage feedback unit is connected to the conditioning agent dosing control system of the main conditioning tank, receives the optimal conditioning agent dosing instruction signal output by the decision control module, and feeds back the optimization result of the bypass device to the main conditioning tank and implements conditioning agent dosing. The transmission of the command signal adopts a hybrid transmission architecture that combines wired and wireless transmission. This allows the optimization results of the bypass device to be synchronized to the reagent dosing control system of the main conditioning tank in a dynamic correction manner. This enables millisecond-level response adjustment of the reagent dosage in the main conditioning tank, ensuring that the spatiotemporal matching degree between the bypass optimization results and the actual dosage in the main tank is ≥95%. This supports the accurate execution of the system when the sludge feeding process and the optimization process are carried out in parallel.

8. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The types of sludge include municipal waste sludge, digested sludge, industrial wastewater sludge, river and lake sediment, pipeline sediment, fecal sludge, organic biogas residue, and pharmaceutical residue. Preferably, the sludge concentration ranges from 1 to 100 g / L.

9. The automatic control system for sludge conditioning and dosing based on bypass sensing signal feedback for precise execution as described in claim 1, characterized in that, The reagents include, but are not limited to, polyaluminum chloride, aluminum chloride and its hydrates, aluminum salts and their hydrates, polyacrylamide, Fenton's reagent, ferric salts and their hydrates, ferrous salts and their hydrates, polyferric sulfate, manganese salts and their hydrates, titanium salts and their hydrates, magnesium salts and their hydrates, calcium salts and their hydrates, etc.

Images