JP7395414B2 - Electrophoresis speed measurement method, electrophoresis speed measurement device, aggregation control device, program and agglutination control system - Google Patents

Description

Embodiments of the present invention relate to an electrophoretic velocity measuring method, an electrophoretic velocity measuring device, an aggregation control device, a program, and an aggregation control system.

Conventionally, as a method for treating water to be treated such as river water, rainwater, sewage, and industrial wastewater, there has been a method in which the impurities contained in the water to be treated are made into flocs using a flocculant, and then the flocs are precipitated and removed. be. In this method, the floc flocculation state affects the quality of the treated water. The flocculation state changes depending on the amount of flocculant injected into the water to be treated. However, the amount of flocculant to be injected to achieve a good floc flocculation state changes with changes in the quality of raw water. For this reason, methods have been studied to appropriately control the amount of coagulant injected so as to improve the floc flocculation state in response to changes in the quality of the water to be treated.

Until now, methods for observing the flocculation state had not been put to practical use, and the amount of coagulant injected was controlled according to fluctuations in the quality of raw water. Normally, in order to control the amount of flocculant injected into the water to be treated so that the floc flocculation state is good, the floc flocculation state should be evaluated and the results should be used to inject the optimal flocculant. It is necessary to calculate the amount.

The charge state of impurities (including flocs) is used as an index for evaluating the floc agglomeration state.

It has been proposed that the charge state of impurities is measured by image processing of the electrophoretic speed of impurities contained in water to be treated to which a voltage is applied.

Patent No. 6270655 JP 2017-56418 Publication Japanese Patent Application Publication No. 2018-143937

The problem to be solved by the present invention is to provide a method for measuring the speed of electrophoresis that can continuously, stably, and accurately measure the speed of electrophoresis of impurities.

In order to achieve the above object, an electrophoresis speed measurement method according to an embodiment includes a movement speed measurement step and an electrophoresis speed measurement step. The movement speed measuring step measures the movement speed of impurities contained in the water to be treated. In the electrophoresis speed measuring step, when the magnitude of the movement speed is smaller than a first set value, a measurement voltage is applied to the water to be treated to measure the electrophoresis speed of the impurity. In the movement speed measuring step, if the magnitude of the movement speed to be measured does not become smaller than the first set value even after a permissible time has elapsed, the step of acquiring treated water different from the treated water is performed. have

FIG. 1 is a diagram showing the configuration of a water treatment plant according to a first embodiment. FIG. 3 is a diagram showing a cell containing a suspension according to the first embodiment. FIG. 3 is a diagram showing the state of the suspension in the cell according to the first embodiment. FIG. 3 is a diagram showing an upward flow of a suspension in a cell according to the first embodiment. FIG. 3 is a diagram showing the operation of the aggregation control device according to the first embodiment. FIG. 2 is a diagram schematically showing the operation of the aggregation control device according to the first embodiment. FIG. 7 is a diagram showing the operation of the aggregation control device according to the second embodiment. FIG. 7 is a diagram schematically showing the operation of the aggregation control device according to the second embodiment. FIG. 7 is a diagram showing a modification of the operation of the aggregation control device according to the second embodiment. FIG. 7 is a diagram showing the operation of the aggregation control device according to the third embodiment. FIG. 7 is a diagram showing the operation of the aggregation control device according to the fourth embodiment. FIG. 7 is a diagram schematically showing the operation of the aggregation control device according to the fourth embodiment.

Embodiments for carrying out the invention will be described below.

(First embodiment)
An electrophoretic velocity measuring method, an electrophoretic velocity measuring device, an aggregation control device, a program, and an aggregation control system according to a first embodiment will be described with reference to FIGS. 1 to 6.

FIG. 1 is a diagram showing the configuration of a water treatment plant 1 according to the first embodiment. The water treatment plant 1 includes a solid-liquid separation process. The solid-liquid separation process is a process in which solids (impurities) such as suspended solids contained in a liquid are separated from the liquid using a flocculant, but the process is not limited to specific equipment. The water treatment plant 1 is, for example, a water purification plant, a sewage treatment plant, an industrial wastewater treatment facility, or the like. When the water treatment plant 1 is a water purification plant, the raw water is, for example, river water, dam lake water, groundwater, rainwater, or sewage. Hereinafter, the water treatment plant 1 will be described as a water purification plant as an example. The water treatment plant 1 is not limited to a water purification plant, and may be a sewage treatment plant, an industrial wastewater treatment facility, or the like.

For example, a water treatment plant 1 shown in FIG. 1 includes a flocculation control system 2 and each water storage section as equipment for realizing a solid-liquid separation function. For example, each water storage section is a landing well 10, a mixing basin 20 (rapid mixing basin), floc formation basins 30-1 to 30-3, a settling basin 40, and a filtration basin 50. Among each water storage section, the landing well 10 is located at the most upstream position with respect to the flow of the water to be treated. Among the water storage units, the filter 50 is located at the most downstream position with respect to the flow of the water to be treated.

The receiving well 10 is a facility that stores the raw water sent to the water treatment plant 1, separates impurities with a relatively large specific gravity such as plants and earth and sand from the raw water, and sends the water to a subsequent water storage section. The raw water here refers to water to be treated, and is sent to the receiving well 10 from inside and outside the water treatment plant 1. “Water to be treated” is water that is being treated by the water treatment plant 1 and that contains target substances that are to be separated by treatment. Further, the water to be treated is a part of the water being treated by the water treatment plant 1, and includes water collected from the water treatment plant 1. Water that has been treated and can be released or reused is referred to as "treated water." That is, raw water can be said to be treated water in an initial state. The water to be treated also includes water that is not returned to the water treatment plant 1 after being collected from the water treatment plant 1 . Furthermore, the term "impurities" as used herein refers to target substances that are to be separated through treatment by the water treatment plant 1. "Impurities" also include those in a state where impurities are aggregated together by a flocculant (to be described later) (floc).

The water landing well 10 is equipped with a water quality meter 11. The water quality meter 11 measures the quality of the water to be treated in the receiving well 10 . For example, water quality is expressed by various quantities such as turbidity, chromaticity, water temperature, electrical conductivity, pH (hydrogen ion concentration index), and alkalinity (acid consumption). The water quality meter 11 transmits information representing water quality obtained by measuring these various quantities to the flocculation control system 2. In the water receiving well 10, relatively large impurities such as plants and earth and sand are separated from the water to be treated by precipitation. The supernatant water from which these impurities have been separated (hereinafter referred to as "supernatant water") is sent to the subsequent mixing tank 20 in a state containing impurities that remained without being separated by precipitation.

A flow meter 12 is provided in the piping between the landing well 10 and the mixing pond 20. The flow meter 12 measures the flow rate of supernatant water sent from the landing well 10 to the mixing pond 20. The flow meter 12 transmits information representing the flow rate of supernatant water sent from the landing well 10 to the mixing pond 20 to the flocculation control system 2.

Supernatant water is sent to the mixing pond 20 from the landing well 10. The flocculation control system 2 injects a flocculant into the water (mixing water) in the mixing pond 20. For example, the flocculant includes aluminum-based inorganic flocculants such as polyaluminum chloride (PAC) and aluminum sulfate (sulfuric acid band). Among these, PAC is mainly used in water treatment plants.

The mixing pond 20 is equipped with a stirring device 21 and a pH meter 22. The stirring device 21 (rapid stirring device) stirs the water in the mixing pond 20. For example, stirring device 21 is a flash mixer. A motor is connected to the stirring device 21, and the stirring speed may be variable. The pH meter 22 continuously measures the pH of the water in the mixing pond 20. The pH meter 22 may measure the pH of the water in the mixing pond 20 intermittently at predetermined intervals. For example, the pH meter 22 measures pH every 10 minutes. The pH meter 22 transmits information representing the pH value of the water in the mixing pond 20 to the flocculation control system 2. The pH meter 22 may be provided in the piping between the mixing pond 20 and the floc formation ponds 30-1 to 30-3. When the flocculant is injected into the mixing pond 20, suspended matter (impurities) contained in the water to be treated coagulates to form flocs. In the mixing pond 20, mixing of the raw water and the flocculant is promoted by the stirring device 21. Impurities in the raw water are coagulated and flocs are formed by promoting the mixing of the raw water and the flocculant. The mixing pond 20 sends the water to be treated in which the raw water and the flocculant are mixed together with the formed flocs to the flocculation ponds 30-1 to 30-3.

The floc formation ponds 30-1 to 30-3 aggregate the flocs formed in the mixing pond 20 to form larger flocs. The floc formation ponds 30-1 to 30-3 have slow stirring devices 31-1 to 31-3 that slowly stir the treated water.

The slow stirring devices 31-1 to 31-3 are set so that the stirring intensity decreases in stages toward the downstream. In other words, the rotational speed of the slow stirring devices 31-1 to 31-3 is highest in the slow stirring device 31-1, and decreases in the order of the slow stirring device 31-2 and the slow stirring device 31-3. As a result, the flocs repeatedly collide with other flocs in the water to be treated, becoming large and prone to settling. The floc formation ponds 30-1 to 30-3 send treated water containing flocs to the settling basin 40.

The sedimentation tank 40 allows the treated water supplied from the floc formation ponds 30-1 to 30-3 to stay there for a predetermined period of time or more, thereby precipitating flocs contained in the treated water. The predetermined time is, for example, about 3 hours. The sedimentation tank 40 sends the water to be treated that has been retained for a predetermined period of time or longer to the filtration tank 50 .

The filtration basin 50 removes minute flocs that were not precipitated and removed in the settling basin 40, for example, by sand filtration. The clean water from which flocs have been removed by the filtration basin 50 is sterilized with chlorine in a water purification basin (not shown), and then distributed to the water pipes. Note that the treated water may be appropriately subjected to ozone treatment or biological activated carbon treatment before being passed through sand filtration in the filter basin 50. Furthermore, the treated water may be subjected to similar treatment after being passed through sand filtration.

The flocculation control device 80 includes a movement speed measuring device 90, a flocculant injection control section 83, and a charging state target value calculation section 84. Some or all of the moving speed measurement device 90, the flocculant injection control section 83, and the charge state target value calculation section 84 are hardware functional sections such as LSI (Large Scale Integration) and ASIC (Application Specific Integrated Circuit). There may be. By executing the program, the flocculating control device 80 calculates the flocculant injection rate setting value calculated according to the charge state of impurities (including flocs) by combining electrophoresis and image processing, and the target flow rate measured by the flow meter 12. The amount of flocculant to be injected is determined based on the flow rate of treated water. The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, magneto-optical disk, ROM, or CD-ROM, or a storage device such as a hard disk built into a computer system. The diagnostic device program may be transmitted via a telecommunications line.

The moving speed measuring device 90 includes a moving speed measuring section 81 and an output section 82.

The moving speed measurement unit 81 is a device that analyzes a portion of the sampled water to be treated and measures a flocculation state index value. In the water treatment plant 1 shown in FIG. 1, a part of the water to be treated is collected from the mixing pond 20. However, this configuration is just an example, and the water to be treated does not necessarily need to be collected from the mixing pond 20. For example, the water to be treated may be collected from a water pipe between the mixing pond 20 and the flocculation ponds 30-1 to 30-3, or may be collected from the flocculation ponds 30-1 to 30-3. Good too. Furthermore, water may be supplied to the moving speed measurement unit 81 by mechanical sampling using a pump or the like, or by an operator of the water treatment plant 1 instead of using a pump.

The collected water to be treated is stored in a predetermined measurement container (hereinafter referred to as "cell 200"). The water to be treated contains impurities and fine flocs. Below, the water to be treated is referred to as a suspension 300 as necessary. The water to be treated is also referred to as test water or sample as necessary.

The moving speed measuring section 81 includes a light source section 810, an imaging section 811, and a speed measuring section 812 as a configuration for measuring the aggregation state index value. The light source section 810 irradiates the cell 200 with light. The light source unit 810 is a light source that emits, for example, laser light or visible light. The light source section 810 may be configured to be able to change the intensity and wavelength of the emitted light.

The imaging unit 811 is configured using an imaging device such as a camera. The imaging unit 811 has an optical system that receives scattered light emitted from the light source unit 810 and reflected by the surface of the floc in the water to be treated. The imaging unit 811 is arranged at a position where it can image the water to be treated within the cell 200. For example, the imaging unit 811 is installed on the side of the cell 200 so that the suspension 300 can be imaged through the transparent side of the cell 200. The imaging unit 811 images the suspension 300 at predetermined intervals, as shown in FIG. 2 . The predetermined period is, for example, a period of 1/3 second to 1 second. When the predetermined period is a 1/3 second period, the imaging unit 811 generates three frames of image data per second. Fine flocs with neutralized surface charges move not only in the direction of the electric field but also in two-dimensional directions. The imaging unit 811 outputs the generated image data to the speed measuring unit 812 at each imaging time.

The speed measuring unit 812 performs image analysis processing using software on the image data output from the imaging unit 811, and measures the moving speed of the flocs in the water to be treated. Specifically, the speed measurement unit 812 measures the position of each floc in the suspension 300 in the image data output from the imaging unit 811. The speed measurement unit 812 measures the position of each floc at different imaging times. Here, an arbitrary imaging time is defined as a first imaging time, and an imaging time after a predetermined period is defined as a second imaging time. The interval between the first imaging time and the second imaging time is, for example, a 1 second interval or a ⅓ second interval. The velocity measuring unit 812 measures the electrophoretic velocity of the flocs based on the position of the flocs at the first imaging time and the position of the flocs at the second imaging time. Further, the speed measuring unit 812 may measure the average speed of electrophoresis of the flocs based on the positions of the flocs at two or more imaging times. The velocity measurement unit 812 outputs measurement data of the electrophoretic velocity of each measured floc to the output unit 82 .

The output unit 82 acquires measurement data of the electrophoretic velocity of each floc outputted by the velocity measuring unit 812. The output unit 82 calculates the average value of the electrophoretic velocity of each floc based on the measurement data of the electrophoretic velocity of each floc. The measurement data used to calculate the average value is the measurement data captured over a period of 1 to 5 minutes. During this 1 to 5 minutes, several tens to several hundred flocs are observed. The output unit 82 calculates the average value of the electrophoretic speed in one measurement by statistically processing the electrophoretic speed of each floc. The output unit 82 outputs information representing the average value of the electrophoresis velocity to the flocculant injection control unit 83.

The charging state target value calculation unit 84 calculates a control target value when determining the flocculant injection rate of the flocculant injection device 70 using a feedback control method. Feedback control is a control method that causes the controlled amount to follow the control target value by varying the manipulated variable based on the deviation between the controlled amount and the control target value. The charging state target value calculation unit 84 includes a water quality meter 11 that measures the water quality of the landing well 10 , a pH meter 22 that measures the water quality of the mixing basin 20 , a sedimentation basin water quality meter 41 that measures the water quality of the settling basin 40 , and a filtration basin 50 . A target value of the charging state is calculated based on information from the filter water level meter 51 that measures the water level of the filter. Note that the target value may be manually input by the operator, or may be calculated from information on the raw water quality of the receiving well 10, the treated water quality of the settling tank 40, and the speed of clogging of the filtration tank 50. . When the operator manually inputs the target value, the operator inputs it from the target value manual input section 60. The target value manual input unit 60 is, for example, a keyboard, a mouse, a touch panel, or the like. The charging state target value calculation unit 84 outputs the calculated target value to the flocculant injection control unit 83.

The flocculant injection control section 83 controls the flocculant injection device based on the target value calculated by the charge state target value calculation section 84 and the information representing the average value of the electrophoresis velocity calculated by the flocculant injection control section 83. A flocculant injection amount of 70 is determined as the manipulated variable. For example, the flocculant injection control unit 83 executes feedback control such as P control (Proportional Controller), PI control (Proportional-Integral Controller), and PID control (Proportional-Integral-Differential Controller). . The flocculant injection control unit 83 outputs the determined flocculant injection amount to the flocculant injection device 70. The flocculant injection amount may be a flocculant injection rate, which is the amount of flocculant injected per unit time.

The flocculant injection device 70 injects the flocculant into the mixing pond 20 under control from the flocculation control device 80 .

Next, the floc agglomeration state will be explained.

The floc flocculation state differs depending on the amount of flocculant injected into the water to be treated. The surface of a suspended object is normally negatively charged in water. On the other hand, as the flocculant, one that is positively charged in water is used. Therefore, the flocculant adheres to the suspended matter (impurities). The flocculant attached to the suspension cancels out the negative charge of the suspension, thereby bringing the surface potential of the suspension close to 0 [mV]. Therefore, the flocculant has the effect of weakening the repulsion between suspended objects and increasing the number of collisions. Due to the action of this coagulant, the flocs that collide with each other gradually become agglomerated, promoting the formation of larger flocs.

If the amount of coagulant to be injected is insufficient, the average value of the surface potential of the suspended matter will remain negative and the suspended matter will repel each other. Therefore, if the amount of coagulant injected is insufficient, the formation of flocs will not proceed sufficiently. On the other hand, if the amount of coagulant injected is excessive, the average value of the surface potential of the suspended matter becomes positive and the suspended matter repel each other. Therefore, even in a situation where the amount of coagulant injected is excessive, the formation of flocs does not proceed sufficiently. On the other hand, when the amount of flocculant injected is appropriate, the surface charge of the suspended matter is neutralized and the suspended matter is attracted to each other by the action of intermolecular forces. Therefore, under conditions where the amount of coagulant injected is appropriate, floc formation progresses. Therefore, it is desirable that the amount of coagulant injected is controlled to an appropriate amount that neutralizes the surface charge of the suspension (brings the surface potential close to about 0 [mV]).

FIG. 2 is a diagram showing a cell 200 containing a suspension 300 according to the first embodiment. The material of the cell 200 is, for example, a transparent material such as glass or acrylic. The cell 200 includes an electrode 210 at an end in the positive direction of the x-axis in the figure, and an electrode 220 at an end in the negative direction of the x-axis. That is, the cell 200 has a pair of electrodes 210 and 220. Further, the electrode 210 and the electrode 220 are arranged to face each other in the x-axis direction. Electrode 210 and electrode 220 are connected to voltage application section 230. The voltage application unit 230 applies a voltage between the electrode 210 and the electrode 220. In FIG. 2, the negative electrode of the voltage application section 230 is connected to the electrode 210. Hereinafter, the electrode connected to the negative electrode of the voltage application section 230 will be referred to as a cathode as necessary. Further, the positive electrode of the voltage application section 230 is connected to the electrode 220. Hereinafter, the electrode connected to the positive electrode of the voltage application section 230 will be referred to as an anode as necessary. In FIG. 2, the voltage application unit 230 applies a negative potential to the electrode 210 and a positive potential to the electrode 220. The measurement voltage when measuring the moving speed of the flocs is, for example, 10 to 40V. The voltage application time is, for example, 3 to 5 minutes. After applying the voltage for 3 to 5 minutes, the suspension 300 is replaced. By applying this voltage, the positively or negatively charged flocs in the suspension 300 move in the direction of the electrode 210 or the electrode 220 (in the direction of the electric field). Hereinafter, it is assumed that the moving speed in the positive direction of the x-axis is represented by a positive value, and the moving speed in the negative direction of the x-axis is represented by a negative value. Similarly, the moving speed in the positive direction of the y-axis is represented by a positive value, and the moving speed in the negative direction of the y-axis is represented by a negative value. Here, the depth (thickness) of the measurement container (cell) in the Z-axis direction is, for example, 1 mm to 3 mm. When a voltage is applied to the suspension 300, fine flocs having a negative surface charge electrophores in the negative direction of the x-axis toward the electrode 220 to which a positive potential is applied. Therefore, the average velocity of electrophoresis of flocs in suspension 300 with a negative surface charge is a negative value.

Since the direction of the electric field due to the measurement voltage is approximately the direction of the x-axis, the direction of the electric field will be hereinafter referred to as the x-axis direction as necessary. Furthermore, since the y-axis direction is included in the direction intersecting the direction of the electric field due to the measurement voltage, hereinafter, the direction intersecting the direction of the electric field due to the measurement voltage will be referred to as the y-axis direction as needed.

When a voltage is applied to the suspension 300, fine flocs with a positive surface charge electrophores in the positive direction of the x-axis toward the electrode 210 to which a negative potential is applied. Therefore, the average velocity of electrophoresis of flocs in suspension 300 with a positive surface charge is a positive value.

Fine flocs with neutralized surface charges float within the suspension 300 even when a voltage is applied. Therefore, the direction of electrophoresis of fine flocs with neutralized surface charges is not constant even when a voltage is applied between the electrodes 210 and 220. Therefore, the variation in the moving speed of each individual floc becomes large, and the dispersion of the moving speed becomes large. The dispersion value of the electrophoretic velocity of fine flocs whose surface charges are neutralized becomes a predetermined value or more. That is, by setting this predetermined value as a threshold value and comparing the dispersion value when a voltage is applied with the threshold value, it is possible to grasp whether or not the surface charge is neutralized.

As described above, by measuring the speed of electrophoresis of the flocs within the suspension 300, the surface charge state (charged state) of the flocs can be obtained. However, in the cell 200 that continuously measures the charge state of the flocs, a phenomenon occurs in which the flocs move immediately after the suspension 300 is sealed in the cell 200 even though no voltage is applied. .

This is due to the generation of a flow due to the impact of closing the containment valve being transmitted to the suspension 300 in the cell 200, and the flow caused by the temperature difference between the water temperature of the suspension 300 and the air temperature around the cell 200. Possible causes include the occurrence of convection, and the occurrence of convection of the suspension 300 due to a change in the volume inside the cell 200 due to the accumulation of deposits such as flocs on the glass inner wall of the cell 200.

FIG. 3 is a diagram showing the state of the suspension 300 in the cell 200 according to the first embodiment. Normally, immediately after the suspension 300 is sealed in the cell 200 and before the measurement voltage is applied, the floc should be almost stationary. However, as shown in FIG. 3, a phenomenon in which the flocs move in a certain direction may be observed immediately after encapsulation. If such movement is observed, it is impossible to accurately measure the electrophoretic velocity in the electrode direction depending on the charge state of the flocs that is originally intended to be measured.

Furthermore, the convection generated by the temperature difference between the water temperature of the suspension 300 and the air temperature around the cell 200 has an upward flow within the cell 200 as described above.

FIG. 4 is a diagram showing the appearance of flocs affected by the upward flow of the suspension 300 in the cell 200 according to the first embodiment. As shown in FIG. 4, the greater the temperature difference between the water temperature of the suspension 300 and the air temperature around the cell 200, the greater the upward flow. For example, the colder the water temperature of the suspension 300 and the higher the temperature around the cell 200, the greater the upward flow will occur. This increases the movement of the flocs in the y-axis direction.

When measuring the movement speed, if only the electrophoretic velocity of the flocs in the x-axis direction is used when the measurement voltage is applied, if the movement in the y-axis direction due to the upward flow becomes too large, the original x-axis direction Electrophoresis speed may decrease. Therefore, a method for measuring the speed of electrophoresis described below is carried out.

FIG. 5 is a flowchart showing the operation of the aggregation control device 80 according to the first embodiment.

FIG. 6 is a diagram schematically showing the operation of the aggregation control device 80 according to the first embodiment.

As shown in FIG. 5, the operation of the aggregation control device 80 is a processing flow related to outputting the speed of electrophoresis of impurities. As explained above, after the suspension 300 is enclosed in the cell 200, the movement of the flocs should be almost stationary, but due to convection of the suspension 300 inside the cell 200, the flocs move. may be seen. This convection will slow down after a while. Therefore, in this embodiment, after the water to be treated (suspension 300) is enclosed, the movement speed of impurities (including flocs) starts to be quantified, and the size of the movement speed in the x-axis direction (electric field direction) is The measurement voltage is applied from the time when the voltage becomes smaller than the separately set setting value (first setting value), and the electrophoresis of impurities (including flocs) is performed based on the information acquired in the time period after starting the application of the measurement voltage. The purpose is to find the speed of

In step S101, water to be treated (suspension 300) is passed into the cell 200, and valves before and after the cell 200 are closed. The suspension 300 is part of the water to be treated collected from the mixing pond 20. A suspension 300 is collected from the mixing pond 20 and passed through the cell 200. Next, the valves before and after the cell 200 are closed. The work of closing the valves before and after the cell 200 may be performed mechanically using an electric switch or the like, or may be performed manually by an operator of the water treatment plant 1.

In step S102, the movement speed measurement unit 81 continuously images impurities (including flocs) in the suspension 300 as shown in FIG. The moving speed in the x-axis direction and the y-axis direction is measured. This moving speed is the moving speed of impurities in a state where no measurement voltage is applied. This moving speed may be the moving speed of impurities along a certain direction, or may be the magnitude of the moving speed. Further, when there are a plurality of impurities, the moving speed may be an average value of the moving speeds of each impurity, or may be a median value or a maximum value of the moving speeds of the plurality of impurities. In this embodiment, step S102 is called a moving speed measuring step.

In step S103, the moving speed measuring unit 81 determines whether the magnitude of the moving speed measured in step S102 is smaller than the first set value. The first set value is a threshold value of the movement speed of impurities to such an extent that it is impossible to correctly measure the electrophoretic speed in the direction of the electric field according to the charge state of the impurities (including flocs) to be measured. The first set value may be arbitrarily set by the operator or administrator. In step S103, if the average value of the moving speeds in the x-axis direction among the moving speeds of individual impurities is smaller than the first set value, the process proceeds to S104. In step S103, if the average value of the moving speeds in the x-axis direction among the moving speeds of individual impurities is greater than or equal to the first set value, the process proceeds to step S102. In this embodiment, the determination is made based on the average value of the moving speed in the x-axis direction of the moving speed of each impurity, but it is not limited to the moving speed in the x-axis direction. The determination may be made based on the value.

In step S104, the movement speed measurement unit 81 applies a measurement voltage to the suspension 300, as shown in FIG. 6(b).

In step S105, as shown in FIG. 6(c), the moving speed measurement unit 81 continuously images impurities (including flocs) in the suspension 300 to which the measurement voltage is applied, and performs image processing to The speed of electrophoresis of individual impurities in the x-axis direction and the y-axis direction in the suspension 300 while a measurement voltage is being applied is measured. The speed of electrophoresis in this embodiment is a measured value of the moving speed of impurities contained in the suspension 300 to which a measurement voltage is applied.

In step S106, the output unit 82 calculates a temporal average value of the moving speed of impurities (including flocs) in the x-axis direction after a predetermined measurement time has elapsed. The predetermined measurement time is, for example, 3 to 5 minutes, which is the application time of the measurement voltage. In this embodiment, S104 to S106 are referred to as an electrophoresis velocity measurement step.

Steps S100 to S107 in FIG. 5 are repeatedly executed, for example, at predetermined time intervals. Alternatively, the process proceeds to step S100 immediately after step S107 ends.

In this embodiment, data on the movement speed from immediately after the sample (suspension 300) is enclosed until it becomes equal to or less than the threshold value (first set value) is excluded, and when there is no movement in the x-axis direction, By applying a measurement voltage and using subsequent data, it is possible to accurately quantify the original speed of electrophoresis of flocs.

In addition, even if the time it takes for the movement to decrease immediately after the sample (suspension 300) is encapsulated varies depending on the water quality, water temperature, or water treatment plant, this function can be used to universally calculate the original electrophoresis speed numerically. It becomes possible to convert into

(Second embodiment)
In addition to the processing of the first embodiment, the second embodiment employs only the data of flocs whose moving speed in the y-axis direction is less than or equal to a threshold value (second set value), and This outputs the migration speed.

An electrophoretic velocity measuring method, an electrophoretic velocity measuring device, an aggregation control device, a program, and an aggregation control system according to a second embodiment will be described with reference to FIGS. 7 and 8. The configurations of the electrophoresis velocity measurement method, electrophoresis velocity measurement device, aggregation control device, program, and aggregation control system are the same as those in the first embodiment, so the same reference numerals are given and explanations are omitted. .

FIG. 7 is a diagram showing the operation of the aggregation control device 80 according to the second embodiment.

FIG. 8 is a diagram schematically showing the operation of the aggregation control device 80 according to the second embodiment. 8(a) to 8(c) are similar to FIGS. 6(a) to 6(c).

As shown in FIG. 7, S200 to S205 are the same as S100 to S105 according to the first embodiment, so a description thereof will be omitted.

In step S206, the movement speed measurement unit 81 measures the movement speed of each impurity (including flocs) in the x-axis direction and the electrophoresis in the y-axis direction after a predetermined measurement time has elapsed, as shown in FIG. 8(d). In a pair of speeds, only data in which the magnitude of the electrophoresis speed in the y-axis direction is equal to or less than the second set value are adopted, and an average value is calculated. The predetermined measurement time is, for example, 3 to 5 minutes, which is the application time of the measurement voltage, as in the first embodiment. The second set value is a threshold value for the electrophoresis speed in the y-axis direction of the flocs, which is such that it is impossible to correctly measure the electrophoresis speed in the electrode direction according to the charge state of the flocs to be measured. . The second set value may be arbitrarily set by the operator or administrator.

After the measurement voltage is applied, the electrophoresis speed of each impurity (including flocs) is calculated as a pair of electrophoresis speed in the x-axis direction and electrophoresis speed in the y-axis direction. Here, there are cases where impurities appear that increase the electrophoresis speed in the y-axis direction due to upward flow within the cell 200 or the like. This phenomenon becomes more likely to occur as the measurement time becomes later.

Therefore, in the second embodiment, in a pair of electrophoretic velocity in the x-axis direction and electrophoretic velocity in the y-axis direction of individual impurities (including flocs), the magnitude of the electrophoretic velocity in the y-axis direction is Only the data of impurities for which is less than the threshold (second set value) are adopted, and the average value of the electrophoresis velocity in the x-axis direction is calculated. Impurities that move significantly in the positive direction of the y-axis due to upward flow or the like such that the electrophoresis velocity in the y-axis direction exceeds a threshold value (second set value) are excluded from the calculation of the average value of the electrophoresis velocity.

Steps S200 to S207 in FIG. 7 are repeatedly executed at predetermined time intervals or immediately after step S207 ends.

FIG. 9 is a diagram showing a modification of the operation of the aggregation control device according to the second embodiment. 9(a) to 9(d) are similar to FIGS. 8(a) to 8(d).

As shown in FIG. 9(e), rather than excluding using a threshold value (second set value) in the y-axis direction, Based on the ratio, the electrophoretic velocity of impurities (including flocs) that are significantly affected by upward flow is excluded. In this embodiment, the magnitude of the electrophoretic velocity of the impurity in the electric field direction (x-axis direction) and the direction of the electric field are such that it is impossible to accurately measure the electrophoretic velocity depending on the charge state of the impurity to be measured. The threshold value of the ratio to the magnitude of the electrophoretic velocity in the intersecting direction (y-axis direction) is called an "acceptable ratio." For example, when the ratio of the y-axis electrophoresis velocity to the x-axis electrophoresis velocity is large, the angle between the actual impurity movement direction and the y-axis direction becomes small. Such a state is determined based on the ratio of the magnitude of the y-axis electrophoresis velocity to the magnitude of the x-axis electrophoresis velocity, and the data is excluded. Furthermore, if extremely heavy impurities are mixed in and the sedimentation speed is high, the angle between the movement direction and the y-axis direction will be small, so the data will be excluded.

In this embodiment, by the method described above, the electrophoresis speed can be quantified only from impurities (including flocs) that mainly electrophores in the horizontal direction (x-axis direction).

(Third embodiment)
In the third embodiment, an allowable waiting time (allowable time) until the moving speed in the x-axis direction becomes equal to or less than a threshold value (first set value) is set, and when the allowable time is exceeded, The measurement is completed, and the sample (suspension 300) in the cell 200 is forcibly replaced.

An electrophoretic velocity measuring method, an electrophoretic velocity measuring device, an aggregation control device, a program, and an aggregation control system according to the third embodiment will be described with reference to FIG. 10. The configurations of the electrophoresis velocity measurement method, electrophoresis velocity measurement device, aggregation control device, program, and aggregation control system are the same as those in the first embodiment, so the same reference numerals are given and explanations are omitted. .

FIG. 10 is a diagram showing the operation of the aggregation control device 80 according to the third embodiment.

As shown in FIG. 10, S300 to S307 are similar to S100 to S107 according to the first embodiment. If the determination in step S303 is NO, the process advances to step S308.

In step S308, it is determined whether the time is within the allowable time. In step S308, if the time is within the allowable time, the process advances to step S302. In step S308, if the moving speed does not become smaller than the first set value even if the allowable time is exceeded, the process advances to step S309.

In step S309, the water (suspension 300) in the cell 200 is replaced. Specifically, the suspension in the cell 200 is drained, and the next suspension is sampled. That is, if the magnitude of the moving speed does not become smaller than the first set value even after the permissible time has elapsed, the water to be treated is drained and another water to be treated is obtained. The other treated water is a portion of water that is being treated by the same water treatment plant 1 as the discharged treated water, which is different from the discharged treated water.

As shown in FIG. 10, before applying the measurement voltage, the measurement of the electrophoresis speed is waited until the magnitude of the movement speed in the x-axis direction becomes smaller than a threshold value (first set value). , even if you wait for a long time, the value may not fall below the threshold (first set value). This is the case, for example, when small air bubbles are mixed into the cell 200 and the water (suspension 300) in the cell 200 is vibrating. In this embodiment, an allowable waiting time (allowable time) until the magnitude of the movement speed in the x-axis direction becomes smaller than a threshold value (first set value) is set, and when the predetermined time is exceeded, In this case, the measurement ends and the sample (suspension 300) in the cell 200 is forcibly replaced.

In this embodiment, by the method described above, it is possible to quickly proceed to the next step, and the time for updating the electrophoresis speed can be accelerated.

(Fourth embodiment)
In the fourth embodiment, immediately after the water to be treated (suspension 300) is sealed, the movement in the x-axis direction is forcibly reduced, instead of applying a measurement voltage and waiting until the movement in the x-axis direction becomes small. Thus, a deceleration voltage is applied in the opposite direction to the movement of the impurities so as to cancel out the movement of the impurities.

An electrophoretic velocity measuring method, an electrophoretic velocity measuring device, an aggregation control device, a program, and an aggregation control system according to the fourth embodiment will be described with reference to FIGS. 11 and 12. The configurations of the electrophoresis velocity measurement method, electrophoresis velocity measurement device, aggregation control device, program, and aggregation control system are the same as those in the first embodiment, so the same reference numerals are given and explanations are omitted. .

FIG. 11 is a diagram showing the operation of the aggregation control device 80 according to the fourth embodiment.

FIG. 12 is a diagram schematically showing the operation of the aggregation control device 80 according to the fourth embodiment.

As shown in FIG. 11, S400 to S402 are similar to S100 to S102 according to the first embodiment. Further, as shown in FIG. 12, FIG. 12(a) is similar to FIG. 6(a). Further, FIG. 12(c) is similar to FIG. 6(b).

In step S403, a deceleration voltage is applied in a direction to cancel the movement of impurities (including flocs) in the x-axis direction. Step S403 is referred to as a "deceleration step" in this embodiment.

In this embodiment, immediately after filling the water to be treated (suspension 300) in the cell 200, without applying a measurement voltage and waiting until the movement in the x-axis direction becomes small, the cell 200 is forced to move in the x-axis direction. It is characterized by applying a deceleration voltage in the opposite direction to the movement of impurities (including flocs) so that the magnitude of the velocity is reduced. Here, it also has the function of changing the polarity of the voltage depending on the direction in which the impurity moves in the x-axis direction. Specifically, impurities are often negatively charged, and if this impurity is migrating toward the cathode, applying a deceleration voltage in this state will reduce the force of the impurity moving toward the anode in the opposite direction. , the initial movement becomes smaller. On the other hand, if negatively charged impurities are migrating toward the anode, applying a deceleration voltage in that state will cause them to migrate further toward the anode, so the polarities of the anode and cathode should be swapped. All that is required is to apply a deceleration voltage.

If the deceleration voltage is applied for too long, electrophoresis will start depending on the deceleration voltage, so it is best to repeat the application in pulses for short periods of time, as shown in the upper part of FIG. 12(d). Furthermore, as shown in the lower part of Fig. 12(d), the magnitude of the deceleration voltage applied here may be constant, or a large deceleration voltage may be applied in a pulsed manner at first, and then the deceleration voltage may be gradually increased in steps. A method of lowering it may also be adopted. When applying a constant deceleration voltage, the magnitude of the deceleration voltage is, for example, 20 to 30V. When a large deceleration voltage is initially applied in a pulsed manner and the deceleration voltage is gradually lowered in steps, the magnitude of the initial large deceleration voltage is, for example, 40 to 60V. It is also conceivable to measure the moving speed when no voltage is applied and set the deceleration voltage value according to the moving speed. Furthermore, when applying pulses, it is also possible to measure the moving speed between pulses and change the voltage value of the next pulse.

In step S404, the movement speed measurement unit 81 determines whether the magnitude of the movement speed after step S403 is smaller than the first set value. In step S404, if the magnitude (for example, average value) of the moving speed in the x-axis direction among the moving speeds of individual impurities (including flocs) is smaller than the first set value, the process advances to S405. In step S404, if the moving speed of each impurity in the x-axis direction is equal to or higher than the first set value, the process proceeds to step S403.

Steps S405 to S408 are the same as steps S104 to S107 in FIG. 5, so their explanation will be omitted.

This embodiment uses the method described above to reduce the initial movement (moving speed) in a short time, then applies a deceleration voltage for measuring the electrophoresis speed, and after applying the measurement voltage, By determining the average value of the electrophoretic velocity in the x-axis direction from only the electrophoretic velocity, the electrophoretic velocity of the flocs can be accurately quantified in a short time.

As described above, according to the first to fourth embodiments, an electrophoresis speed measuring method that can continuously, stably, and accurately measure the electrophoresis speed of impurities in water to which a voltage is applied; We can provide electrophoresis rate measuring devices, aggregation control devices, programs, and aggregation control systems.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

1... Water treatment plant 2... Coagulation control system 10... Water landing well 11... Water quality meter 12... Flow meter 20... Mixing pond 21... Stirring device 22... pH meter 30-1, 30-2, 30-3...Floc formation pond 31-1, 31-2, 31-3...Slow stirring device 40...Sedimentation basin 41...Settlement basin water quality meter 50 ...filtration basin 51...filtration basin water level gauge 60...target value manual input section 70...flocculant injection device 80...coagulation control device 81...movement speed measuring section 82...output Section 83... Coagulant injection control section 84... Charge state target value calculation section 90... Movement speed measuring device 200... Cells 210, 220... Electrodes 230 at both ends of the cell... Voltage application Section 300...Suspension 810...Light source section 811...Imaging section 812...Speed measurement section

Claims (19)

a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
has
In the movement speed measuring step, if the magnitude of the movement speed to be measured does not become smaller than the first set value even after a permissible time has elapsed, the step of acquiring treated water different from the treated water. has,
Method for measuring the rate of electrophoresis of impurities. a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
a deceleration step of applying a deceleration voltage to the water to be treated to reduce the moving speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
A method for measuring the speed of electrophoresis of impurities. The deceleration step applies a stepwise lower deceleration voltage from a high deceleration voltage.
The method for measuring the speed of electrophoresis of impurities according to claim 2 . In the electrophoresis velocity measuring step, an average value of velocity components in the electric field direction due to the measurement voltage is output for the measured electrophoresis velocity of a plurality of impurities.
The method for measuring the rate of electrophoresis of impurities according to any one of claims 1 to 3 . In the electrophoretic velocity measuring step, the electrophoretic velocity of the plurality of impurities is separated into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction intersecting the direction of the electric field, and
outputting an average value of the velocity component in the direction of the electric field for impurities whose magnitude of the velocity component in the direction intersecting the direction of the electric field is equal to or less than a second set value;
The method for measuring the speed of electrophoresis of impurities according to claim 4 . In the electrophoretic velocity measuring step, the electrophoretic velocity of the plurality of impurities is separated into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction intersecting the direction of the electric field, and
outputting an average value of velocity components in the direction of the electric field for impurities where the magnitude of the velocity component in the direction intersecting the direction of the electric field with respect to the magnitude of the velocity component in the direction of the electric field is equal to or less than a permissible ratio;
The method for measuring the speed of electrophoresis of impurities according to claim 4 . a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
has
In the electrophoresis velocity measuring step, outputting an average value of velocity components in the electric field direction due to the measurement voltage for the measured electrophoresis velocity of a plurality of impurities;
In the electrophoretic velocity measuring step, the electrophoretic velocity of the plurality of impurities is separated into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction intersecting the direction of the electric field, and
outputting an average value of velocity components in the direction of the electric field for impurities where the magnitude of the velocity component in the direction intersecting the direction of the electric field with respect to the magnitude of the velocity component in the direction of the electric field is equal to or less than a permissible ratio;
Method for measuring the rate of electrophoresis of impurities. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; Measuring the speed of electrophoresis of impurities contained in the water to be treated to which a voltage has been applied , and if the measured movement speed does not become smaller than the first set value even after a permissible time elapses, a speed measurement unit that acquires water to be treated that is different from the water to be treated ;
An apparatus for measuring the rate of electrophoresis of impurities. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and reducing the moving speed of the impurities contained in the water to be treated; Applying a deceleration voltage to the water to be treated, and measuring the speed of electrophoresis of impurities contained in the water to be treated to which the measurement voltage is applied when the magnitude of the movement speed becomes smaller than a first set value. a speed measurement unit,
An apparatus for measuring the rate of electrophoresis of impurities. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; a speed measuring unit that measures the speed of electrophoresis of impurities contained in the water to be treated to which a voltage is applied;
Equipped with
The velocity measurement unit outputs an average value of velocity components in the electric field direction due to the measurement voltage regarding the measured electrophoresis velocity of a plurality of impurities,
measuring the electrophoretic velocity of the plurality of impurities by decomposing it into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction crossing the direction of the electric field,
outputting an average value of velocity components in the direction of the electric field for impurities where the magnitude of the velocity component in the direction intersecting the direction of the electric field with respect to the magnitude of the velocity component in the direction of the electric field is equal to or less than a permissible ratio;
Impurity electrophoresis rate measuring device. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; Measuring the speed of electrophoresis of impurities contained in the water to be treated to which a voltage has been applied , and if the measured movement speed does not become smaller than the first set value even after a permissible time elapses, a speed measurement unit that acquires water to be treated that is different from the water to be treated ;
a flocculant injection control section that determines the amount of flocculant to be injected by the flocculant injection device based on the electrophoresis speed of impurities measured by the speed measuring section;
A coagulation control device comprising: an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and reducing the moving speed of the impurities contained in the water to be treated; Applying a deceleration voltage to the water to be treated, and measuring the speed of electrophoresis of impurities contained in the water to be treated to which the measurement voltage is applied when the magnitude of the movement speed becomes smaller than a first set value. a speed measurement unit,
a flocculant injection control section that determines the amount of flocculant to be injected by the flocculant injection device based on the electrophoresis speed of impurities measured by the speed measuring section;
A coagulation control device comprising: an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; a speed measuring unit that measures the speed of electrophoresis of impurities contained in the water to be treated to which a voltage is applied;
a flocculant injection control section that determines the amount of flocculant to be injected by the flocculant injection device based on the electrophoresis speed of impurities measured by the speed measuring section;
Equipped with
The velocity measurement unit outputs an average value of velocity components in the electric field direction due to the measurement voltage regarding the measured electrophoresis velocity of a plurality of impurities,
measuring the electrophoretic velocity of the plurality of impurities by decomposing it into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction crossing the direction of the electric field,
outputting an average value of velocity components in the direction of the electric field for impurities where the magnitude of the velocity component in the direction intersecting the direction of the electric field with respect to the magnitude of the velocity component in the direction of the electric field is equal to or less than a permissible ratio;
Coagulation control device. to the computer,
a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
run the
In the movement speed measuring step, if the magnitude of the movement speed to be measured does not become smaller than the first set value even after a permissible time has elapsed, the step of acquiring treated water different from the treated water. A program to run . to the computer,
a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
a deceleration step of applying a deceleration voltage to the water to be treated to reduce the moving speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
A program to run. to the computer,
a movement speed measurement step of measuring the movement speed of impurities contained in the water to be treated;
an electrophoresis speed measuring step of applying a measurement voltage to the water to be treated to measure the speed of electrophoresis of the impurities when the magnitude of the movement speed is smaller than a first set value;
run the
In the electrophoresis velocity measuring step, outputting an average value of velocity components in the electric field direction due to the measurement voltage for the measured electrophoresis velocity of a plurality of impurities;
In the electrophoretic velocity measuring step, the electrophoretic velocity of the plurality of impurities is separated into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction intersecting the direction of the electric field, and
A program for outputting an average value of velocity components in the electric field direction for impurities for which the magnitude of the velocity component in a direction crossing the electric field direction with respect to the magnitude of the velocity component in the electric field direction is less than or equal to a permissible ratio . an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; Measuring the speed of electrophoresis of impurities contained in the water to be treated to which a voltage has been applied , and if the measured movement speed does not become smaller than the first set value even after a permissible time elapses, a speed measurement unit that acquires water to be treated that is different from the water to be treated ;
a flocculant injection device that injects a flocculant in an amount determined based on the electrophoresis speed of impurities measured by the speed measurement unit;
Agglomeration control system with. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and reducing the moving speed of the impurities contained in the water to be treated; Applying a deceleration voltage to the water to be treated, and measuring the speed of electrophoresis of impurities contained in the water to be treated to which the measurement voltage is applied when the magnitude of the movement speed becomes smaller than a first set value. a speed measurement unit,
a flocculant injection device that injects a flocculant in an amount determined based on the electrophoresis speed of impurities measured by the speed measurement unit;
Agglomeration control system with. an imaging unit that images the water to be treated;
measuring the moving speed of impurities contained in the water to be treated based on at least two images captured by the imaging unit, and measuring when the moving speed becomes smaller than a first set value; a speed measuring unit that measures the speed of electrophoresis of impurities contained in the water to be treated to which a voltage is applied;
a flocculant injection device that injects a flocculant in an amount determined based on the electrophoresis speed of impurities measured by the speed measurement unit;
has
The velocity measurement unit outputs an average value of velocity components in the electric field direction due to the measurement voltage regarding the measured electrophoresis velocity of a plurality of impurities,
measuring the electrophoretic velocity of the plurality of impurities by decomposing it into a velocity component in the direction of the electric field due to the measurement voltage and a velocity component in a direction crossing the direction of the electric field,
outputting an average value of velocity components in the direction of the electric field for impurities where the magnitude of the velocity component in the direction intersecting the direction of the electric field with respect to the magnitude of the velocity component in the direction of the electric field is equal to or less than a permissible ratio;
Coagulation control system.

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