A method for detecting concentration of suspended particles in water body and a water pollution detector

Abstract

The application provides a water body suspended particle concentration detection method and a water pollution detector. The frequency response signals of each detection point are collected, a plurality of characteristic frequencies when the polarization of the suspended particles is delayed by the excitation electric field are identified from the frequency response signals, the dielectric properties of the suspended particles in the water body to be measured at each characteristic frequency are determined, the concentration profile of the suspended particles is determined based on all the dielectric properties, the cumulative settlement amount when the concentration reaches a steady state is determined through the concentration profile and the temperature change characteristics of the water body to be measured, the water body to be measured is extracted and flows through the detection area of the microfluidic chip, and the concentration of the suspended particles in the water body to be measured is determined according to the pulse signal of the water body to be measured and a preset concentration calibration curve. The application can improve the accuracy of the concentration detection of the water body to be measured by combining the dielectric properties of the suspended particles and the real-time settlement characteristics in the water body to be measured.

Description

Technical Field

[0001] This application relates to the field of concentration detection technology, and more specifically, to a method for detecting the concentration of suspended particulate matter in water and a water pollution detector. Background Technology

[0002] Rapid and accurate detection of suspended particulate matter (such as silt, microplastics, colloidal pollutants, etc.) in water bodies has become a core requirement for environmental monitoring and water quality management. Traditional concentration detection methods include turbidity method, gravimetric method, laser scattering method, etc.

[0003] In the field of suspended particulate matter detection in water, traditional methods face a contradiction between accuracy and efficiency. For example, high-precision detection (such as gravimetric methods) requires waiting for the particles to settle completely, which takes several hours to several days and cannot meet the needs of emergency monitoring. In recent years, dielectric spectroscopy (analyzing particle polarization characteristics through electric field excitation) and microfluidic chip detection technology have attracted attention due to their advantages such as high sensitivity and strong anti-interference. Existing dielectric spectroscopy methods mostly focus on static suspension analysis and have not solved the signal drift problem in the dynamic sedimentation process. Microfluidic detection usually relies on offline preprocessing, which is difficult to link and optimize with the sedimentation process. It only analyzes fixed suspensions and ignores the dynamic changes in concentration distribution during sedimentation. It lacks real-time judgment of sedimentation steady state, resulting in sampling too early or too late, poor data representativeness, and data that is out of touch with the real scene. Therefore, how to combine the dielectric properties of suspended particulate matter with the real-time sedimentation characteristics in the water body to improve the accuracy of concentration detection in the water body to be tested has become a problem facing the industry. Summary of the Invention

[0004] This application provides a method for detecting the concentration of suspended particulate matter in water and a water pollution detector, which can improve the accuracy of concentration detection in the water body by combining the dielectric properties of suspended particulate matter and its real-time sedimentation characteristics in the water body to be tested.

[0005] In a first aspect, this application provides a method for detecting the concentration of suspended particulate matter in water, wherein an intelligent sensor array is pre-set and the water to be tested is introduced into a detection chamber with multiple detection points for sedimentation. The method includes the following steps:

[0006] During the settling process, excitation electric fields of different frequencies are applied to the water body to be tested, and the frequency response signals of each detection point are collected through the intelligent sensor array.

[0007] From all the frequency response signals collected by the intelligent sensor array, multiple characteristic frequencies at which the polarization of suspended particles by the excitation electric field is delayed are identified, and then the dielectric properties of suspended particles in the water body under test are determined at each characteristic frequency. Based on all the dielectric properties, the concentration profile of the suspended particles during sedimentation is determined.

[0008] The cumulative sedimentation amount of suspended particulate matter when the concentration reaches a steady state during sedimentation is determined by the concentration profile and the temperature change characteristics of the water body under electric field excitation.

[0009] When the number of suspended particles settled reaches the cumulative settling amount, it is determined that the concentration of suspended particles has reached a steady state during the settling process. The water body to be tested is extracted by the intelligent sensor array and flows through the detection area of ​​the microfluidic chip. The concentration of suspended particles in the water body to be tested is determined based on the pulse signal when the water body passes through the detection area and the preset concentration calibration curve.

[0010] In some embodiments, identifying multiple characteristic frequencies from all frequency response signals acquired by the intelligent sensing array that indicate a delay in the polarization of suspended particulate matter by the excitation electric field specifically includes:

[0011] Select one frequency response signal from all the frequency response signals collected by the intelligent sensing array as the selected frequency response signal;

[0012] Determine the frequency response curve of the selected frequency response signal;

[0013] Based on the frequency response curve, determine several characteristic frequencies at which the polarization of suspended particulate matter is delayed by the excitation electric field.

[0014] Continue to determine multiple characteristic frequencies of the remaining frequency response signal.

[0015] In some embodiments, determining the dielectric properties of suspended particulate matter in the water body under test at various characteristic frequencies specifically includes:

[0016] Obtain the complex permittivity of pure water from a standard database;

[0017] Select a detection point as the selected detection point, and determine multiple effective complex permittivity of the selected detection point;

[0018] Based on all characteristic frequencies, all effective complex dielectric constants, and the complex dielectric constant of the pure water at the selected detection point, determine multiple volume fractions of suspended particulate matter and multiple complex dielectric constants of suspended particulate matter at the selected detection point;

[0019] Based on all complex permittivity, determine multiple conductivity values ​​of suspended particulate matter at selected detection points;

[0020] The set of all conductivity, all volume fraction, and all complex permittivity of suspended particulate matter is taken as the dielectric properties of suspended particulate matter at each characteristic frequency of the selected detection point.

[0021] Continue to determine the dielectric properties of suspended particulate matter at each characteristic frequency of the remaining detection points.

[0022] In some embodiments, determining the concentration profile of the suspended particulate matter during sedimentation based on all dielectric properties specifically includes:

[0023] Determine the location coordinates of each detection point;

[0024] The contrast factor of the suspended particulate matter at each detection point is determined based on all dielectric properties;

[0025] The average volume fraction of the suspended particulate matter at each detection point is determined based on all dielectric properties;

[0026] The concentration profile of the suspended particulate matter during sedimentation was determined based on all average volume fractions, all contrast factors, and all location coordinates.

[0027] In some embodiments, determining the cumulative sedimentation amount of suspended particulate matter when the concentration reaches a steady state during sedimentation, based on the concentration profile and the temperature change characteristics of the water body under electric field excitation, specifically includes:

[0028] Determine the temperature change characteristics of the water body under electric field excitation;

[0029] Based on the concentration profile, multiple concentration gradients of the suspended particulate matter during the sedimentation process are determined;

[0030] The cumulative sedimentation amount of the suspended particulate matter when its concentration reaches a steady state during the sedimentation process is determined based on the temperature change characteristics and all concentration gradients.

[0031] In some embodiments, determining the suspended particulate matter concentration of the water body to be tested based on the pulse signal when the water body passes through the detection zone and a preset concentration calibration curve specifically includes:

[0032] Obtain the preset concentration calibration curve;

[0033] Determine the total pulse amplitude integral of the pulse signal;

[0034] The total pulse amplitude integral is substituted into the preset concentration calibration curve to obtain the suspended particulate matter concentration of the water body to be tested.

[0035] In some embodiments, a frequency-converting excitation signal is continuously applied to the water body to be tested in the detection chamber via a signal generator to generate an excitation electric field of different frequencies.

[0036] In some embodiments, a portion of the water to be tested is drawn from any location within the detection chamber using a syringe and placed into the microfluidic chip, allowing the drawn water to flow through the detection area of ​​the microfluidic chip.

[0037] In some embodiments, piezoelectric sensors in a smart sensor array are used to acquire frequency response signals at each detection point.

[0038] Secondly, this application provides a water pollution detector, which includes a suspended particulate matter concentration detection unit, the suspended particulate matter concentration detection unit comprising:

[0039] The acquisition module is used to apply excitation electric fields of different frequencies to the water body to be tested during the sedimentation process, and to acquire the frequency response signals of each detection point through the intelligent sensor array.

[0040] The processing module is used to identify multiple characteristic frequencies from all frequency response signals collected by the intelligent sensor array when the polarization of suspended particles by the excitation electric field is delayed, and then determine the dielectric properties of suspended particles in the water body under test at each characteristic frequency, and determine the concentration profile of the suspended particles during sedimentation based on all dielectric properties.

[0041] The processing module is also used to determine the cumulative sedimentation amount of the suspended particulate matter when the concentration reaches a steady state during the sedimentation process by using the concentration profile and the temperature change characteristics of the water body under electric field excitation.

[0042] The execution module is used to determine that the concentration of suspended particulate matter has reached a steady state during the sedimentation process when the number of sedimented suspended particulate matter reaches the cumulative sedimentation amount, and to extract the water body to be tested through the intelligent sensor array and make the water body to be tested flow through the detection area of ​​the microfluidic chip, and to determine the concentration of suspended particulate matter in the water body to be tested based on the pulse signal when the water body to be tested passes through the detection area and the preset concentration calibration curve.

[0043] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects:

[0044] The method and water pollution detector for detecting suspended particulate matter concentration in water provided in this application firstly apply excitation electric fields of different frequencies to the water body to be tested during the sedimentation process, and collect frequency response signals at each detection point through the intelligent sensor array; identify multiple characteristic frequencies from all frequency response signals collected by the intelligent sensor array when the polarization of suspended particulate matter by the excitation electric field is delayed, and then determine the dielectric properties of suspended particulate matter in the water body to be tested at each characteristic frequency, and determine the concentration profile of suspended particulate matter during sedimentation based on all dielectric properties; determine the cumulative sedimentation amount when the concentration of suspended particulate matter reaches a steady state during sedimentation by using the concentration profile and the temperature change characteristics of the water body to be tested under electric field excitation; when the sedimentation amount of suspended particulate matter reaches the cumulative sedimentation amount, it is determined that the concentration of suspended particulate matter has reached a steady state during sedimentation, and the water body to be tested is extracted by the intelligent sensor array and flows through the detection area of ​​the microfluidic chip, and the concentration of suspended particulate matter in the water body to be tested is determined according to the pulse signal when the water body to be tested passes through the detection area and the preset concentration calibration curve.

[0045] Therefore, in the method for detecting suspended particulate matter concentration in water, this application first applies excitation electric fields of different frequencies to the water body during sedimentation, and collects frequency response signals at each detection point through the intelligent sensor array. From all the frequency response signals collected by the intelligent sensor array, multiple characteristic frequencies at which the polarization of suspended particulate matter by the excitation electric field is delayed are identified, thereby determining the dielectric properties of the suspended particulate matter in the water body at each characteristic frequency. Based on all the dielectric properties, the concentration profile of the suspended particulate matter during sedimentation is determined. This concentration profile describes the concentration of suspended particulate matter at each detection point within the spatial dimension of the detection chamber in the water body. The concentration distribution is used to demonstrate the sedimentation behavior and concentration distribution patterns of suspended particulate matter at different times and locations. Secondly, the cumulative sedimentation amount of suspended particulate matter at a steady state during sedimentation is determined by the concentration profile and the temperature change characteristics of the water body under electric field excitation. When the number of sedimented suspended particulate matter reaches the cumulative sedimentation amount, it is determined that the concentration of suspended particulate matter has reached a steady state during sedimentation. The water body to be tested is extracted by the intelligent sensor array and flows through the detection area of ​​the microfluidic chip. The concentration of suspended particulate matter in the water body is determined based on the pulse signal when the water body passes through the detection area and a preset concentration calibration curve. This scheme can improve the accuracy of concentration detection in the water body by combining the dielectric properties of suspended particulate matter and its real-time sedimentation characteristics. Attached Figure Description

[0046] Figure 1 This is an exemplary flowchart of a method for detecting suspended particulate matter concentration in water according to some embodiments of this application;

[0047] Figure 2 This is an exemplary flowchart illustrating the determination of concentration profiles according to some embodiments of this application;

[0048] Figure 3 These are example graphs of concentration calibration curves shown in some embodiments of this application;

[0049] Figure 4 This is a schematic diagram of the structure of a suspended particulate matter concentration detection unit according to some embodiments of this application;

[0050] Figure 5 This is a schematic diagram of the structure of a computer device for implementing a method for detecting the concentration of suspended particulate matter in water, according to some embodiments of this application. Detailed Implementation

[0051] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0052] refer to Figure 1 This figure is an exemplary flowchart of a method for detecting the concentration of suspended particulate matter in water according to some embodiments of this application. Before implementing the method, an intelligent sensor array is pre-set, and the water to be tested is introduced into a detection chamber with multiple detection points for sedimentation. The intelligent sensor array consists of a piezoelectric sensor and an intelligent fluid control module. The method for detecting the concentration of suspended particulate matter in water mainly includes the following steps:

[0053] In step 101, excitation electric fields of different frequencies are applied to the water body to be tested during the settling process, and frequency response signals of each detection point are collected through the intelligent sensor array.

[0054] In practice, a frequency-modulated excitation signal is continuously applied to the water body under test in the detection chamber through a signal generator (such as the 1451 series agile signal generator) to generate excitation electric fields of different frequencies.

[0055] The applied excitation signal is a linear frequency sweep, with a sweep range of 1Hz to 1MHz, meaning the frequency of the excitation signal changes linearly within the sweep range. A piezoelectric sensor in the intelligent sensor array is used to collect the frequency response signal at each detection point. The frequency response signal is the response signal at each detection point after the excitation signal passes through the water body under test. The frequency response signal includes the frequency and amplitude of the signal. The collected frequency is 2kHz, and the collection time for each frequency is recorded. One collection time corresponds to the frequency and amplitude of one frequency response signal, and one collection time corresponds to one frequency, phase, and amplitude of the excitation signal. Other methods can be used in other embodiments, which will not be elaborated here.

[0056] In step 102, multiple characteristic frequencies at which the polarization of suspended particles is delayed by the excitation electric field are identified from all frequency response signals collected by the intelligent sensing array, thereby determining the dielectric properties of suspended particles in the water body under test at each characteristic frequency, and determining the concentration profile of the suspended particles during sedimentation based on all dielectric properties.

[0057] In some embodiments, identifying multiple characteristic frequencies from all frequency response signals acquired by the smart sensing array at which the polarization of suspended particulate matter by the excitation electric field is delayed can be achieved by the following steps:

[0058] Select one frequency response signal from all the frequency response signals collected by the intelligent sensing array as the selected frequency response signal;

[0059] Determine the frequency response curve of the selected frequency response signal;

[0060] Based on the frequency response curve, determine several characteristic frequencies at which the polarization of suspended particulate matter is delayed by the excitation electric field.

[0061] Continue to determine multiple characteristic frequencies of the remaining frequency response signal.

[0062] In specific implementation, the frequency response curve of the selected frequency response signal can be determined in the following way: the acquisition time of the selected frequency response signal is used as the horizontal axis, and the amplitude of the selected frequency response signal is used as the vertical axis. The frequency response curve of the selected frequency response signal is obtained by combining the above horizontal and vertical axes through Matrix Laboratory (MATLAB). The frequency response curve is a curve describing the change of amplitude and phase of the detected frequency response signal with frequency, including the amplitude, phase and acquisition time of the selected frequency response signal. One acquisition time corresponds to one phase of the frequency response curve. Other methods can also be used to determine the frequency response curve in other embodiments, which are not limited here.

[0063] In specific implementation, determining the multiple characteristic frequencies at which the polarization of suspended particles is delayed by the excitation electric field based on the frequency response curve can be achieved in the following way: Phase extraction is performed on both the excitation signal applied to the water body and the frequency response curve using discrete Fourier transform, resulting in multiple phases of the excitation signal applied to the water body and multiple phases of the frequency response curve. Each phase of the excitation signal corresponds to a phase of the frequency response curve. A selection time is chosen as the selected acquisition time. The phase difference of the frequency response curve at the selected acquisition time is obtained by comparing the phase of the frequency response curve at the selected acquisition time with the phase of the excitation signal at the selected acquisition time. This process is then repeated to determine the phase difference of the frequency response curve during the remaining acquisition time. The phase difference is used as the average of all phase differences to judge all acquisition times. The frequency corresponding to the acquisition time with a phase difference greater than the average of all phase differences is taken as the characteristic frequency when the polarization of suspended particles by the excitation electric field is delayed. When the frequency of the excitation electric field is close to the relaxation frequency of the suspended particles, the polarization process of the suspended particles cannot be completed in time, and the phase of the frequency response signal will lag significantly behind the excitation signal, forming a detectable phase difference. Therefore, the magnitude of the phase difference directly reflects the degree of polarization delay, and the frequency points where the phase difference changes can be taken as the characteristic frequency of the suspended particles. Other methods can also be used to determine the phase difference in other embodiments, which are not limited here.

[0064] It should be noted that the characteristic frequencies in this application refer to the frequencies at which the phase response undergoes a delayed change in the frequency response curve of suspended particulate matter. These frequencies correspond to the polarization relaxation time of suspended particulate matter under electric field excitation, and are used to reflect the degree of influence of the excitation electric field on the suspended particulate matter in the water body under test, which facilitates the subsequent analysis of the dielectric properties of the suspended particulate matter in the water body under test.

[0065] In some embodiments, determining the dielectric properties of suspended particulate matter in the water body under test at various characteristic frequencies can be achieved by the following steps:

[0066] Obtain the complex permittivity of pure water from a standard database;

[0067] Select a detection point as the selected detection point, and determine multiple effective complex permittivity of the selected detection point;

[0068] Based on all characteristic frequencies, all effective complex dielectric constants, and the complex dielectric constant of the pure water at the selected detection point, determine multiple volume fractions of suspended particulate matter and multiple complex dielectric constants of suspended particulate matter at the selected detection point;

[0069] Based on all complex permittivity, determine multiple conductivity values ​​of suspended particulate matter at selected detection points;

[0070] The set of all conductivity, all volume fraction, and all complex permittivity of suspended particulate matter is taken as the dielectric properties of suspended particulate matter at each characteristic frequency of the selected detection point.

[0071] Continue to determine the dielectric properties of suspended particulate matter at each characteristic frequency of the remaining detection points.

[0072] In practice, determining the multiple effective complex permittivity of selected detection points can be achieved in the following way: using a time-domain reflectometer (TDAR). TDR (Transient Reflectometry) measures the high-frequency limiting dielectric constant and the static dielectric constant of the water sample at the highest and lowest frequencies of the excitation electric field. A characteristic frequency is selected from all characteristic frequencies corresponding to a selected detection point. The phase delay at the selected detection point at the selected characteristic frequency is obtained by combining the frequency response curve corresponding to the selected detection point with the selected characteristic frequency using a signal conversion algorithm (such as Fourier transform). The phase delay, selected characteristic frequency, static dielectric constant, and high-frequency limiting dielectric constant are then substituted into the formula for the effective complex dielectric constant to obtain the effective complex dielectric constant at the selected detection point at the selected characteristic frequency. This process is repeated to determine the effective complex dielectric constant at the selected detection points at the remaining characteristic frequencies. The effective complex dielectric constant is a complex parameter describing the dielectric properties of the mixture of pure water and suspended particulate matter in the excitation electric field. The phase delay is a parameter describing the difference in propagation time of the excitation electric field signal at the selected detection point. Other methods can be used in other embodiments, which are not limited here.

[0073] It should be noted that the dielectric properties of the water body under test in this application are affected by pure water, suspended particulate matter, and the frequency of the excitation electric field. The dielectric properties of the water body under test are different at different frequencies. The phase change of the excitation signal when it is transmitted in the water body under test is related to the frequency of the excitation electric field and the dielectric properties of the water body under test. Therefore, the effective complex dielectric constant of the water body under test can be obtained by the dielectric constant and phase change of the water body under the excitation electric field. The dielectric properties refer to the physical characteristics such as polarization, conductivity, and loss exhibited by the water body under the action of the excitation electric field.

[0074] In specific implementation, determining multiple volume fractions and multiple complex permittivity of suspended particles at a selected detection point based on all characteristic frequencies, all effective complex permittivity, and the complex permittivity of pure water can be achieved in the following way: The effective complex permittivity at each characteristic frequency is used as a known result variable of the dielectric mixing model (such as the Bruggeman model); the complex permittivity of pure water is used as a known operation variable of the aforementioned dielectric mixing model; and the complex permittivity and volume fraction of suspended particles are used as unknown variables of the aforementioned dielectric mixing model. Then, a relational equation is constructed at different characteristic frequencies using the aforementioned dielectric mixing model. Finally, data fitting and inversion are performed on all relational equations to obtain the multiple complex permittivity and volume fraction of suspended particles at the selected detection point. The complex permittivity is a complex parameter describing the dielectric properties of suspended particles in the water body under test in the excitation electric field. One characteristic frequency of the selected detection point corresponds to one complex permittivity and one volume fraction of suspended particles. Other methods can also be used in other embodiments, which are not limited here.

[0075] It should be noted that the dielectric properties of the water body to be tested in this application satisfy the dielectric mixing model (such as the Bruggeman model), and the effective complex dielectric constant of the water body to be tested is jointly determined by pure water and suspended particulate matter. Therefore, the effective complex dielectric constant can be obtained by combining the complex dielectric constant of suspended particulate matter, the complex dielectric constant of pure water, and the volume fraction of suspended particulate matter at the selected detection point with the above dielectric mixing model. Since the volume ratio of suspended particulate matter at the detection point has a direct impact on the dielectric properties of the mixture of the water body to be tested, the volume fraction of suspended particulate matter at the selected detection point and the complex dielectric constant of suspended particulate matter can be obtained by inversion based on the above dielectric mixing model, the effective complex dielectric constant, and the complex dielectric constant of pure water.

[0076] In specific implementation, determining multiple conductivities of suspended particles at a selected detection point based on all complex permittivity can be achieved in the following way: Select one complex permittivity as the selected complex permittivity; combine the imaginary part of the selected complex permittivity with the characteristic frequency corresponding to the selected complex permittivity to obtain the conductivity of the suspended particles at the selected detection point at the characteristic frequency corresponding to the selected complex permittivity; continue to determine the conductivity of the remaining complex permittivity. Here, conductivity is a parameter describing the ability of suspended particles to conduct current in the water body under test. One conductivity corresponds to one characteristic frequency. Since the complex permittivity is a complex number composed of a real part and an imaginary part, the imaginary part of the complex permittivity describes the energy loss of suspended particles under an excitation electric field, while conductivity describes the dielectric loss of suspended particles in the water body under an excitation electric field. Therefore, the conductivity of the suspended particles at the selected detection point can be determined by the imaginary part of the complex permittivity of the suspended particles. Other methods can also be used in other embodiments, which are not limited here.

[0077] It should be noted that the dielectric properties in this application refer to the dielectric properties exhibited by suspended particulate matter under the action of an excitation electric field. It is the part of dielectric properties that focuses on the dielectric constant and dielectric loss. The dielectric properties include the aforementioned complex dielectric constant and conductivity, which are used to analyze the polarization and energy loss of the water body under the action of an electric field, so as to facilitate the subsequent analysis of the concentration of suspended particulate matter.

[0078] In some embodiments, reference Figure 2 As shown in the figure, this is a schematic flowchart of the process for determining the concentration profile in some embodiments of this application. In this embodiment, the determination of the concentration profile of the suspended particulate matter during sedimentation based on all dielectric properties can be achieved by the following steps:

[0079] First, in step 1021, the position coordinates of each detection point are determined;

[0080] Secondly, in step 1022, the contrast factor of the suspended particulate matter at each detection point is determined based on all dielectric properties;

[0081] Then, in step 1023, the average volume fraction of the suspended particulate matter at each detection point is determined based on all dielectric properties;

[0082] Finally, in step 1024, the concentration profile of the suspended particulate matter during sedimentation is determined based on all average volume fractions, all contrast factors, and all location coordinates.

[0083] In specific implementation, the position coordinates of each detection point can be determined in the following way: the horizontal plane of the water body to be tested in the detection chamber is used as the reference coordinate plane, the center point of the horizontal plane is used as the origin, the width of the detection chamber is used as the horizontal axis, and the height of the detection chamber is used as the vertical axis. The position coordinates of each detection point are obtained by combining the above horizontal axis, vertical axis and origin. The position coordinates are the coordinates describing the position of each detection point in the detection chamber. Other methods can also be used to determine the position in other embodiments, which are not limited here.

[0084] In specific implementation, determining the contrast factor of the suspended particulate matter at each detection point based on all dielectric properties can be achieved in the following way: Select a dielectric property as the selected dielectric property; select a complex dielectric constant from all complex dielectric constants corresponding to the selected dielectric property as the selected complex dielectric constant; substitute the selected complex dielectric constant and the dielectric constant of pure water into the formula for calculating the contrast factor to obtain the contrast factor of the suspended particulate matter under the selected complex dielectric constant; continue to determine the contrast factor of the suspended particulate matter under the remaining complex dielectric constants of the selected dielectric property; and take the mean of all obtained contrast factors as the contrast factor of the suspended particulate matter. The contrast factor of the particulate matter at the selected dielectric property detection point is used to further determine the contrast factor of the suspended particulate matter at the remaining dielectric property detection points. The contrast factor is a parameter value describing the relationship between the polarizability of the suspended particulate matter in the excitation electric field and the dielectric properties of the surrounding pure water. The complex dielectric constant of the suspended particulate matter varies with frequency, and the characteristic frequency corresponds to a frequency point with significant polarization delay. At these frequencies, the polarization difference between the suspended particulate matter and pure water is most obvious, and the contrast factor can more sensitively reflect the presence and concentration of particles. In other embodiments, other methods can also be used to determine the contrast factor, which is not limited here.

[0085] In specific implementation, the average volume fraction of suspended particulate matter at each detection point can be determined based on all dielectric properties in the following way: select one dielectric property as the selected dielectric property, take the average of all volume fractions in the selected dielectric property as the average volume fraction of the detection point corresponding to the selected dielectric property, and continue to determine the average volume fraction of the detection points corresponding to the remaining dielectric properties; other methods can also be used in other embodiments, which are not limited here.

[0086] In specific implementation, the concentration profile of suspended particulate matter during sedimentation can be determined based on all average volume fractions, all contrast factors, and all location coordinates in the following manner: Using mathematical modeling tools (such as MATLAB), combined with all average volume fractions, all contrast factors, the acquisition time corresponding to all characteristic frequencies, and the location coordinates of each detection point, the concentration change of suspended particulate matter during sedimentation is analyzed using a spatiotemporal evolution model (such as a long short-term memory network). This yields a three-dimensional contour map showing the volume fraction of suspended particulate matter changing with time and location. In this map, time is used as the horizontal axis, location coordinates as the vertical axis, and volume fraction as the vertical axis. The height of the contour lines represents the volume fraction. The spatiotemporal evolution refers to analyzing the dynamic changes of suspended particulate matter in the sedimentation time and spatial dimensions of the detection chamber, using the aforementioned three-dimensional contour map as the concentration profile of suspended particulate matter during sedimentation. Other methods can also be used in other embodiments, which are not limited here.

[0087] It should be noted that the concentration profile in this application describes the distribution of the concentration of suspended particulate matter in the water body under test at various detection points within the spatial dimension of the detection chamber. The concentration profile is usually presented in the form of a curve or image to show the sedimentation behavior and concentration distribution of suspended particulate matter at different times and locations (i.e., changes with time and space), which facilitates subsequent analysis of the steady-state concentration of suspended particulate matter in the water body under test.

[0088] In step 103, the cumulative sedimentation amount of the suspended particulate matter when the concentration reaches a steady state during the sedimentation process is determined by the concentration profile and the temperature change characteristics of the water body under electric field excitation.

[0089] In some embodiments, determining the cumulative sedimentation amount of suspended particulate matter when the concentration reaches a steady state during sedimentation, based on the concentration profile and the temperature change characteristics of the water body under electric field excitation, can be achieved through the following steps:

[0090] Determine the temperature change characteristics of the water body under electric field excitation;

[0091] Based on the concentration profile, multiple concentration gradients of the suspended particulate matter during the sedimentation process are determined;

[0092] The cumulative sedimentation amount of the suspended particulate matter when its concentration reaches a steady state during the sedimentation process is determined based on the temperature change characteristics and all concentration gradients.

[0093] In specific implementation, determining the temperature change characteristics of the water body under electric field excitation can be achieved as follows: A detection point is selected as the chosen detection point. A temperature sensor (such as a thermocouple) is used to collect the temperature of the water body at the chosen detection point under a swept-frequency excitation electric field. All collected temperatures are sorted according to the time points of collection, and the sorted sequence is used as the temperature value sequence of the chosen detection point. The temperature collection frequency is 2kHz, and the overall temperature collection time is the same as the time the excitation electric field is applied. Each time point corresponds to one temperature value. All collected temperature values ​​at the chosen detection point are plotted into a temperature curve using a mathematical modeling tool (such as MATLAB). This temperature curve describes the temperature change of the water body at the chosen detection point over time, with the horizontal axis representing time. The vertical axis represents temperature values. The rate of temperature change for each temperature value in the temperature curve is calculated using the function calculation module of the mathematical modeling tool. The set of all temperature peaks, all rates of temperature change, and temperature stabilization times in the temperature curve is taken as the temperature feature of the selected detection point. Here, the temperature stabilization time refers to the time when the rate of temperature change stabilizes, and the temperature feature refers to the temperature characteristic of the selected detection point. The temperature features of the remaining detection points are then determined, and the set of all obtained temperature features is taken as the temperature change feature of the water body under electric field excitation. Here, the temperature change feature describes the regularity of the temperature of the water body under test as a function of settling time, spatial location, and electric field parameters (such as frequency). In other embodiments, other methods can also be used to determine the temperature, which are not limited here.

[0094] In specific implementation, determining multiple concentration gradients of suspended particulate matter during sedimentation based on the concentration profile can be achieved in the following way: The concentration profile is differentiated using numerical differentiation methods (such as higher-order finite difference methods) to obtain the gradients of the concentration profile in each detection point direction and the gradients of the concentration profile at all time points where the frequency of the excitation electric field changes. The conductivity of pure water is obtained from a standard database (such as the International Standard Atmosphere). Any two detection points are selected as the two designated detection points. All conductivity values ​​corresponding to the two designated detection points are normalized (such as by averaging) to obtain the conductivity gradient between the two designated detection points. The conductivity gradient between the two designated detection points is normalized and corrected using the conductivity and temperature change characteristics of pure water to obtain the concentration gradient of suspended particulate matter at the selected detection points during sedimentation. The concentration gradient of suspended particulate matter at the remaining two arbitrary detection points is then determined. Other methods can also be used in other embodiments, which are not limited here.

[0095] It should be noted that the conductivity gradient in this application is a parameter value describing the change in conductivity between two selected detection points, while the concentration gradient is a parameter value describing the difference in concentration of suspended particulate matter in the water body under test at each detection point. The conductivity and dielectric constant of suspended particulate matter are related to its concentration. For example, conductive particles (such as metal oxides) will directly increase the conductivity of the system, while insulating particles will indirectly affect the conductivity by adsorbing ions or changing the fluidity of the medium. The conductivity of pure water will change with temperature. In order to eliminate the influence of the conductivity of pure water changing with temperature, the temperature change characteristics are corrected for the conductivity of suspended particulate matter, thereby obtaining the concentration gradient.

[0096] In specific implementation, the cumulative sedimentation amount of suspended particulate matter when the concentration reaches steady state during sedimentation can be determined based on the temperature change characteristics and all concentration gradients using the following method: Initialize a cumulative sedimentation amount model, using the temperature change characteristics as the constraint parameters of the model, and then using all concentration gradients as the initialization parameters of the model. The cumulative sedimentation amount when the concentration of suspended particulate matter reaches steady state during sedimentation can then be obtained through the model. It should be noted that the cumulative sedimentation amount model is established using machine learning algorithms (such as regression algorithms or neural networks). For example, the cumulative sedimentation amount when the concentration of suspended particulate matter reaches steady state during sedimentation = A * all concentration gradients (i.e., initialization parameters) + B * temperature change characteristics (i.e., constraint parameters), where A and B are weighting coefficients. A and B can be determined by fitting the historical dataset of the cumulative sedimentation amount training using a multiple linear regression method (such as least squares). Other methods can also be used in other embodiments, which are not limited here.

[0097] It should be noted that the cumulative settling amount in this application is a parameter value describing the total settling amount of suspended particulate matter in the water body to be tested during settling. It is used to assess the settling situation of suspended particulate matter in the water body to be tested, so as to facilitate the extraction of the water body to be tested when the concentration of suspended particulate matter in the water body to be tested is stable after settling.

[0098] In step 104, when the number of suspended particles settled reaches the cumulative settling amount, it is determined that the concentration of suspended particles has reached a steady state during the settling process. The water body to be tested is extracted by the intelligent sensor array and flows through the detection area of ​​the microfluidic chip. The concentration of suspended particles in the water body to be tested is determined based on the pulse signal when the water body passes through the detection area and the preset concentration calibration curve.

[0099] In specific implementation, a variable frequency excitation signal is continuously applied to the water body to generate excitation electric fields of different frequencies, and the volume fraction of suspended particulate matter at each detection point of the water body is continuously monitored. When the concentration profile formed by the volume fraction of suspended particulate matter at each detection point reaches the cumulative sedimentation amount, the excitation signal is stopped. A portion of the water body to be tested is extracted from any position in the detection chamber through an intelligent sensor array and placed into a microfluidic chip, so that the extracted water body flows through the detection area of ​​the microfluidic chip. The microfluidic chip has detection electrodes (such as AgCl electrodes), which continuously send electric fields to the detection area. The signal acquisition module of the microfluidic chip (such as a resistance pulse detection system) collects the pulse signal caused by the flow of suspended particulate matter in the extracted water body through the detection area. The acquisition frequency is 2kHz, and the pulse signal contains multiple signal amplitudes, with one signal amplitude corresponding to one acquisition time point. Other methods can also be used in other embodiments, which will not be elaborated here.

[0100] In some embodiments, the concentration of suspended particulate matter in the water to be tested can be determined based on the pulse signal when the water body passes through the detection zone and a preset concentration calibration curve by the following steps:

[0101] Obtain the preset concentration calibration curve;

[0102] Determine the total pulse amplitude integral of the pulse signal;

[0103] The total pulse amplitude integral is substituted into the preset concentration calibration curve to obtain the suspended particulate matter concentration of the water body to be tested.

[0104] In practice, a suspension of known concentration (such as a polystyrene particle suspension) is flowed through the detection area of ​​a microfluidic chip. A signal acquisition device (such as a high-speed data acquisition card) collects the pulse signal and pulse duration as the suspension passes through the detection area. The pulse signal includes multiple amplitude values. All amplitude values ​​and pulse durations of the suspension's pulse signal are substituted into a pulse amplitude integration formula to obtain the multiple pulse amplitude integrals of the suspension. (Refer to...) Figure 3 As shown, this figure is an example of a concentration calibration curve in some embodiments of this application. The concentration of the suspension is used as the horizontal axis, and the integral of all pulse amplitudes corresponding to the suspension is used as the vertical axis. The concentration calibration curve of the suspension is plotted by combining the above-mentioned horizontal and vertical axes using mathematical modeling tools (such as MATLAB). Other methods can also be used to determine the concentration in other embodiments, which are not limited here.

[0105] In specific implementation, the pulse amplitude integral of the pulse signal can be determined in the following way: select a signal amplitude from the pulse signal as the selected signal amplitude, substitute the selected signal amplitude and the sampling frequency into the pulse amplitude integral formula to obtain the pulse amplitude integral of the selected signal amplitude, and continue to determine the pulse amplitude integral of the remaining signal amplitudes in the pulse signal. Here, the pulse amplitude integral is a parameter value describing the energy of a single pulse signal. The sum of all obtained pulse amplitude integrals is taken as the total pulse amplitude integral of the pulse signal. Here, the total pulse amplitude integral is a parameter value describing the overall intensity of the pulse signal. When suspended particulate matter passes through the detection area of ​​the microfluidic chip, it causes a change in the signal intensity of the electric field applied in the microfluidic chip, thereby generating a pulse signal. Therefore, the concentration of suspended particulate matter has a direct impact on the signal intensity of the pulse signal. The signal intensity of the pulse signal can be represented by the cumulative change in the signal amplitude of the pulse signal during the sampling time. In other embodiments, other methods can also be used to determine this, which are not limited here.

[0106] It should be noted that the preset concentration calibration curve in this application is a curve that describes the quantitative relationship between the concentration of a suspension with a known concentration (such as a polystyrene particle suspension) and the pulse amplitude integral of the pulse signal. Through the concentration calibration curve, the signal value (such as the pulse amplitude integral) of the water body to be tested can be converted into the corresponding concentration value of the water body to be tested, thereby realizing the quantitative analysis of the concentration of suspended particulate matter in the water body to be tested, that is, determining the concentration of suspended particulate matter in the water body to be tested.

[0107] Furthermore, in another aspect of this application, in some embodiments, this application provides a water pollution detector that can be used to detect the concentration of suspended particulate matter in water. This water pollution detector includes a suspended particulate matter concentration detection unit. (Refer to...) Figure 4 The figure is a schematic diagram of the structure of a suspended particulate matter concentration detection unit according to some embodiments of this application. The suspended particulate matter concentration detection unit includes: a data acquisition module 401, a processing module 402, and an execution module 403, which are described below:

[0108] The acquisition module 401 in this application is mainly used to apply excitation electric fields of different frequencies to the water body to be tested during the sedimentation process, and to acquire the frequency response signals of each detection point through the intelligent sensor array.

[0109] Processing module 402, in this application, is used to identify multiple characteristic frequencies from all frequency response signals collected by the intelligent sensing array when the polarization of suspended particles by the excitation electric field is delayed, thereby determining the dielectric properties of suspended particles in the water body under test at each characteristic frequency, and determining the concentration profile of the suspended particles during sedimentation based on all dielectric properties.

[0110] It should be noted that the processing module 402 in this application is also used to determine the cumulative sedimentation amount of the suspended particulate matter when the concentration reaches a steady state during the sedimentation process by using the concentration profile and the temperature change characteristics of the water body under electric field excitation.

[0111] The execution module 403 in this application is mainly used to determine that the concentration of suspended particulate matter has reached a steady state during the sedimentation process when the amount of sedimentation of the suspended particulate matter reaches the cumulative sedimentation amount, and to extract the water body to be tested through the intelligent sensor array and make the water body to be tested flow through the detection area of ​​the microfluidic chip, and to determine the concentration of suspended particulate matter in the water body to be tested based on the pulse signal when the water body to be tested passes through the detection area and the preset concentration calibration curve.

[0112] In addition, this application also provides a computer device, the computer device including a memory and a processor, the memory storing code, and the processor being configured to acquire the code and execute the above-described method for detecting the concentration of suspended particulate matter in water.

[0113] In some embodiments, reference Figure 5 The figure is a schematic diagram of the structure of a computer device for implementing a method for detecting the concentration of suspended particulate matter in water, according to some embodiments of this application. The method for detecting the concentration of suspended particulate matter in water in the above embodiments can be implemented through... Figure 5 The computer device shown is used to implement this, and the computer device includes at least one processor 501, a communication bus 502, a memory 503, and at least one communication interface 504.

[0114] Processor 501 can be a general-purpose central processing unit (CPU) or an application-specific integrated circuit (ASIC).

[0115] The communication bus 502 can be used to transmit information between the aforementioned components.

[0116] Memory 503 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CDROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.), magnetic disks or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. Memory 503 may exist independently and be connected to processor 501 via communication bus 502. Memory 503 may also be integrated with processor 501.

[0117] The memory 503 stores program code for executing the scheme of this application, and its execution is controlled by the processor 501. The processor 501 executes the program code stored in the memory 503. The program code may include one or more software modules. The method used in the above embodiments can be implemented by the processor 501 and one or more software modules in the program code in the memory 503.

[0118] Communication interface 504 uses any transceiver-like device to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.

[0119] In a specific implementation, as one example, a computer device may include multiple processors, each of which may be a single-core (single CPU) processor or a multi-core (multi CPU) processor. Here, a processor may refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0120] The aforementioned computer device can be a general-purpose computer device or a special-purpose computer device. In specific implementations, the computer device can be a desktop computer, a portable computer, a network server, a handheld digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, a communication device, or an embedded device. This application does not limit the type of computer device.

[0121] In addition, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for detecting suspended particulate matter concentration in water.

[0122] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0123] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for detecting concentration of suspended particles in a body of water, wherein, The method comprises the following steps: During the sedimentation process, different frequency excitation electric fields are applied to the water body to be measured, and the frequency response signals of each detection point are collected by the intelligent sensing array; From all the frequency response signals collected by the intelligent sensing array, multiple characteristic frequencies are identified when the polarization of suspended particles is delayed by the excitation electric field, and the dielectric properties of the suspended particles in the water body to be measured at each characteristic frequency are determined, and the concentration profile of the suspended particles during the sedimentation process is determined based on all the dielectric properties; The cumulative sedimentation amount of the suspended particles when the concentration reaches a steady state during the sedimentation process is determined by the concentration profile and the temperature change characteristics of the water body to be measured under the excitation of the electric field; When the sedimentation amount of the suspended particles reaches the cumulative sedimentation amount, it is determined that the concentration of the suspended particles reaches a steady state during the sedimentation process, and the water body to be measured is extracted by the intelligent sensing array and flows through the detection area of the microfluidic chip, and the concentration of the suspended particles in the water body to be measured is determined according to the pulse signal when the water body to be measured passes through the detection area and the preset concentration calibration curve; The method comprises the following steps: The complex dielectric constant of pure water is obtained from a standard database; A detection point is selected as a selected detection point, and multiple effective complex dielectric constants of the selected detection point are determined; The multiple volume fractions and multiple complex dielectric constants of the suspended particles of the selected detection point are determined according to all the characteristic frequencies, all the effective complex dielectric constants, and the complex dielectric constant of the pure water; The multiple conductivities of the suspended particles of the selected detection point are determined based on all the complex dielectric constants; The set of all conductivities, all volume fractions, and all complex dielectric constants of the suspended particles are taken as the dielectric properties of the suspended particles at each characteristic frequency of the selected detection point; The dielectric properties of the suspended particles at each characteristic frequency of the remaining detection points are determined.

2. The method of claim 1, wherein, The method comprises the following steps: A frequency response signal is selected from all the frequency response signals collected by the intelligent sensing array as a selected frequency response signal; The frequency response curve of the selected frequency response signal is determined; The multiple characteristic frequencies when the polarization of the suspended particles is delayed by the excitation electric field are determined according to the frequency response curve; The multiple characteristic frequencies of the remaining frequency response signals are determined.

3. The method of claim 1, wherein, The method comprises the following steps: The position coordinates of each detection point are determined; The contrast factors of the suspended particles at each detection point are determined according to all the dielectric properties; The average volume fractions of the suspended particles at each detection point are determined according to all the dielectric properties; The concentration profile of the suspended particles during the sedimentation process is determined according to all the average volume fractions, all the contrast factors, and all the position coordinates.

4. The method of claim 1, wherein, The cumulative settling amount of the suspended particles when the concentration reaches a steady state during the settling process is determined based on the concentration profile and the temperature variation characteristic of the water body under the excitation of the electric field, and specifically includes: determining the temperature variation characteristic of the water body under the excitation of the electric field; determining a plurality of concentration gradients of the suspended particles during the settling process based on the concentration profile; determining the cumulative settling amount of the suspended particles when the concentration reaches a steady state during the settling process according to the temperature variation characteristic and all the concentration gradients.

5. The method of claim 1, wherein, The concentration of the suspended particles in the water body to be measured is determined according to the pulse signal of the water body to be measured when passing through the detection area and a preset concentration calibration curve, and specifically includes: obtaining a preset concentration calibration curve; determining the total pulse amplitude integral of the pulse signal; obtaining the concentration of the suspended particles in the water body to be measured by bringing the total pulse amplitude integral into the preset concentration calibration curve.

6. The method of claim 1, wherein, The signal generator continuously applies a variable-frequency excitation signal to the water body to be measured in the detection chamber to generate excitation electric fields of different frequencies.

7. The method of claim 1, wherein, The syringe extracts part of the water body to be measured at any position in the detection chamber and puts it into the microfluidic chip, so that the extracted water body to be measured flows through the detection area of the microfluidic chip.

8. The method of claim 1, wherein, The frequency response signals of each detection point are collected by using the piezoelectric sensors in the intelligent sensing array.

9. A water pollution detector for detecting the concentration of suspended particles in a water body using the method according to any one of claims 1 to 8, the water pollution detector comprising a suspended particle concentration detecting unit, characterized in that, The suspended particle concentration detection unit includes: The collection module is used to apply excitation electric fields of different frequencies to the water body to be measured during the settling process, and collect the frequency response signals of each detection point by using the intelligent sensing array; The processing module is used to identify a plurality of characteristic frequencies when the polarization of the suspended particles under the excitation of the electric field is delayed from all the frequency response signals collected by the intelligent sensing array, and then determine the dielectric properties of the suspended particles in the water body to be measured under each characteristic frequency, and determine the concentration profile of the suspended particles during the settling process based on all the dielectric properties; The processing module is also used to determine the cumulative settling amount of the suspended particles when the concentration reaches a steady state during the settling process based on the concentration profile and the temperature variation characteristic of the water body under the excitation of the electric field; The execution module is used to determine that the concentration of the suspended particles reaches a steady state during the settling process when the settling amount of the suspended particles reaches the cumulative settling amount, extract the water body to be measured by the intelligent sensing array and make the water body to be measured flow through the detection area of the microfluidic chip, and determine the concentration of the suspended particles in the water body to be measured according to the pulse signal of the water body to be measured when passing through the detection area and the preset concentration calibration curve.

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