Aggregation state determination method and aggregation processing method

Abstract

The aggregation state determination method according to the present invention is a method for irradiating a liquid containing particles with laser light and determining the aggregation state of the particles on the basis of the amplitude of change in the light reception intensity of scattered light obtained by scattering the laser light by the particles, and comprises: a correlation acquisition step for acquiring a correlation between the particles and the laser light; obtaining the correlation between the particle size of the particles and the change amplitude of the light receiving intensity; and a determination step for determining the aggregation state of the particles on the basis of the correlation.

Description

Technical Field

[0001] The present invention relates to a method for determining a clustering state and a method for processing a clustering state. This application claims priority based on Japanese Patent Application No. 2022-116997 filed in Japan on July 22, 2022, and the contents thereof are hereby cited. Background Art

[0002] When agglomeration treatment is performed to remove impurities and organic matter from various wastewater or water, inorganic agglomerating agents such as ferric chloride or polyaluminium chloride and polymer agglomerating agents are sometimes used together. As a result, particles in the treated liquid aggregate, making the solid-liquid separation operation in the later stage easier. Furthermore, the amount of sludge generated can be reduced by suppressing the amount of inorganic agglomerating agents added.

[0003] Furthermore, when dehydrating the sludge generated by biological treatment of drainage, there is also a case where an inorganic coagulant and a polymer coagulant are used for aggregation treatment before dehydration. This can effectively neutralize the charge of the sludge, improve the floc strength, and significantly reduce the water content of the sludge (dehydrated cake) after dehydration.

[0004] The appropriate amount of flocculant needs to be added according to the water quality of the treated liquid or the properties of the treated sludge. In the aggregation treatment of drainage and water, if the amount of flocculant added (dosage) is insufficient, the removal of impurities or organic matter contained in the treated liquid becomes insufficient, and the water quality of the treated liquid deteriorates. On the other hand, if the dosage is excessive, there is a possibility that the flocculant leaks to the subsequent stage and causes an increase in the load in the subsequent stage treatment or contamination of the subsequent stage treatment equipment.

[0005] Furthermore, in the sludge treatment, if the dosage is insufficient, the charge neutralization of the sludge becomes insufficient, and there is a case where the floc strength decreases and the moisture content of the dehydrated cake increases, or the sludge leaks into the dehydrated separation liquid. Moreover, if the dosage becomes excessive, the floc strength also decreases, and there is a case where the moisture content of the dehydrated cake increases, or the sludge leaks into the dehydrated separation liquid.

[0006] In order to determine the most preferred dosage, a beaker test (jar test) or a table test such as agglomeration, filtration, and squeezing test (Buchner funnel test) is basically performed. In addition, in the operation management of the dehydrator, the factors and operation amounts to be operated when a problem occurs are determined based on the judgment made by the operator's operating experience or the confirmation results of the dehydration effect (filterability or floc strength, dehydrated cake moisture content, etc.) obtained by the above-mentioned table test.

[0007] However, the judgment based on the operator's experience is qualitative, so it may take more time than expected to improve the situation, or the dehydration effect may be reduced due to incorrect operation. In addition, although the judgment based on the table test is quantitative, it is difficult to evaluate continuously, so it takes time before the operating conditions are changed to reflect the results of the table test.

[0008] As a method for solving the above-mentioned problem, Patent Document 1 describes irradiating a liquid to be processed with laser light and controlling the addition of an aggregating agent using an aggregation state monitoring sensor that receives scattered light scattered by particles in the liquid to measure the aggregation state of the particles.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2017-26438 Summary of the invention

[0012] Problems to be solved by the invention

[0013] According to the technology described in Patent Document 1, it is believed that the particle size distribution state of aggregated particles can be estimated by generating an aggregation index based on the amplitude (variation amplitude) of the received signal intensity of scattered light obtained by an aggregation monitoring device using scattered light in the treated liquid. Moreover, according to the technology described in Patent Document 1, it is believed that the excess or deficiency of the amount of aggregating agent added can be evaluated and the amount of aggregating agent added can be continuously adjusted. However, the inventors and others conducted research and found that when the particle size of the particles in the treated liquid is smaller than and larger than the diameter of the measurement area for measuring the particle size, the correlation between the particle size and the aggregation-related index generated by the amplitude of the received signal intensity of the scattered light is reversed in positive and negative. The phenomenon results in a situation where it is impossible to distinguish between particles with a smaller diameter than the diameter of the measurement area and particles with a larger diameter than the measurement area.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aggregation state determination method and an aggregation treatment method capable of more accurately determining the aggregation state of particles in a liquid to be processed.

[0015] Technical means of solving problems

[0016] The gist of the present invention is as follows.

[0017] [1] A method for determining an aggregation state in one form of the present invention is a method for irradiating laser light into a liquid containing particles and determining the aggregation state of the particles based on the amplitude of the change in light receiving intensity of scattered light formed by scattering the laser light by the particles, and includes: a correlation acquisition step of acquiring the correlation between the particle size of the particles and the amplitude of the change in light receiving intensity; and a determination step of determining the aggregation state of the particles based on the correlation.

[0018] [2] In the aggregation state determination method described in [1], in the correlation acquisition step, the relationship between the amount of aggregating agent added and the amplitude of the change in the light receiving intensity can be obtained, and the correlation between the particle size and the amplitude of the change in the light receiving intensity can be obtained from the relationship.

[0019] [3] In the aggregation state determination method described in [1] or [2], the correlation between the particle size and the amplitude of the light receiving intensity change can be determined by the relationship between the particle size and the beam diameter of the laser light.

[0020] [4] In the aggregation state determination method described in [1], the correlation may show a positive correlation when the particle size is less than the beam diameter, and a negative correlation when the particle size is greater than the beam diameter.

[0021] [5] Furthermore, another form of the aggregation processing method of the present invention is an aggregation processing method for adding an aggregating agent to a liquid containing particles to aggregate the particles, and includes: a determination step of irradiating laser light into the liquid and determining the aggregation state of the particles based on the amplitude of the light receiving intensity change of the scattered light formed by scattering the laser light by the particles; and an aggregating agent adding step of adding the aggregating agent in an amount based on the aggregation state of the particles determined in the determination step, and the determination step includes: a correlation acquisition step of acquiring the correlation between the particle size of the particles and the amplitude of the light receiving intensity change; and a determination step of determining the aggregation state of the particles based on the correlation.

[0022] Effects of the Invention

[0023] According to the above aspect of the present invention, the aggregation state of particles in the liquid to be processed can be determined more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] [ Figure 1 ] is a structural diagram showing an example of the structure of an aggregation processing device to which the aggregation state determination method of the first embodiment of the present invention can be applied.

[0025] [ Figure 2 ] is a structural diagram showing an example of the structure of a probe included in an aggregation state monitoring sensor.

[0026] [ Figure 3 ] is a flowchart showing the process of the aggregation state determination method of the first embodiment of the present invention.

[0027] [ Figure 4 ] is a schematic diagram of the measurement area of ​​the aggregation status monitoring sensor.

[0028] [ Figure 5A ] is a diagram showing an example of a detection waveform obtained using an aggregation state monitoring sensor.

[0029] [ Figure 5B ] is a diagram showing an example of a detection waveform obtained using an aggregation state monitoring sensor.

[0030] [ Figure 6 ] is a diagram illustrating an apparatus used to study the relationship between particle size and the amplitude of change in received light intensity.

[0031] [ Figure 7 ] is a curve graph showing the relationship between particle size and large peak appearance rate.

[0032] [ Figure 8 ] is a diagram used to illustrate the research conducted by the inventors of the present invention.

[0033] [ Fig. 9 ] is a diagram used to illustrate the research conducted by the inventors of the present invention.

[0034] [ Fig.10 ] is a graph showing an example of the cumulative degree of change in the light receiving intensity.

[0035] [ Fig.11 ] is a diagram used to illustrate the area of ​​the detection waveform diagram representing the temporal variation of the light receiving intensity.

[0036] [ Fig.12 ] is a curve graph showing the correlation equation.

[0037] [ Fig.13 ] is a graph showing an example of the variation amplitude of light receiving intensity and the cumulative generation frequency.

[0038] [ Fig.14 ] is a flowchart showing the process of the aggregation processing method of the second embodiment of the present invention.

[0039] [ Fig.15 ] is a flow chart showing the process of the first aggregating agent adding step in the same embodiment.

[0040] [ Fig.16 ] is a flow chart showing the process of the second aggregating agent adding step in the same embodiment. DETAILED DESCRIPTION

[0041] <<Configuration example of aggregation processing device>>

[0042] First, an example of a clustering processing device to which the clustering state determination method according to one embodiment of the present invention can be applied will be described. Figure 1 This is a structural diagram showing an example of an aggregation processing device to which the aggregation state determination method of this embodiment can be applied.

[0043] like Figure 1 As shown, in the aggregation treatment device, the treated liquid is introduced into the treatment tank 3 via the inflow pipe 1 including the flow meter 2, and the aggregation agent is added to the treatment tank 3 by the dosing device 4. The treatment tank 3 is provided with a stirrer 3a and an aggregation state monitoring sensor 10, and the detection signal generated by the aggregation state monitoring sensor 10 is input to the controller 8. The controller 8 controls the dosing device 4 based on the detection signal.

[0044] The aggregating agent may be an inorganic aggregating agent or an organic aggregating agent, or these may be used in combination.

[0045] The aggregation state monitoring sensor 10 is preferably the one described in Patent Document 1. The aggregation state monitoring sensor 10 includes a probe 100 . Figure 2 The structure of the probe 100 included in the aggregation state monitoring sensor 10 is shown. The probe 100 includes: a block 101, including mutually orthogonal surfaces 101a, surface 101b and a top 101c where these intersect; a light emitting unit 102, which is arranged along the surface 101a and irradiates laser light to the treated liquid; and a light receiving unit 103, which is arranged along the surface 101b and sets the light receiving optical axis to a direction orthogonal to the light emitting optical axis of the light emitting unit 102. In addition, the aggregation state monitoring sensor 10 includes a light emitting circuit, a detection circuit and a measuring circuit (not shown) in order to analyze the light emitting action of the light emitting unit 102 and the light receiving signal of the light receiving unit 103. The measuring circuit includes a timing circuit, an analog to digital (A / D) conversion unit, a calculation unit, etc.

[0046] Similar to Patent Document 1, in the probe 100, the laser light irradiated from the light-emitting section 102 to the measuring area A near the top 101c is scattered by the particles in the measuring area A. The scattered light is received by the light receiving section 103, and the aggregation state is measured based on the time-dependent change in the intensity of the scattered light received by the light receiving section 103. In addition, the block 101 includes an opaque material. The diameter of the measuring area A in the cross section perpendicular to the optical axis of the laser light L, in other words, the diameter of the laser light L is, for example, 1 mm. As described below, the diameter of the measuring area A is a threshold value for the reversal of the correlation between the particle size and the intensity of the scattered light received by the light receiving section 103, that is, the amplitude of the change in the light receiving intensity. Therefore, in order to appropriately determine the required aggregation state, the diameter of the measuring area A can be appropriately changed.

[0047] The light-emitting circuit sends an electrical signal having a certain modulation frequency relative to the light-emitting unit to the light-emitting unit 102 according to the signal from the timing circuit. The light-emitting unit 102 emits laser light according to the signal from the light-emitting circuit. The light-receiving unit 103 receives scattered light generated by the collision of the laser light with the particles contained in the treated water, and converts the scattered light into an electrical signal. The detection circuit removes the modulation component contained in the electrical signal from the light-receiving unit 103, and outputs a light-receiving voltage corresponding to the light-receiving intensity.

[0048] The measuring circuit transmits a signal for emitting light (a specific frequency modulated wave) to the light emitting circuit, converts the signal from the detection circuit into a digital signal, performs a logical operation, and outputs information related to the collection.

[0049] As the aggregation state monitoring sensor 10, the monitoring device of Patent Document 1, in particular, the monitoring device described in Japanese Patent No. 6281534 to which the patent is granted, can be preferably used, but the present invention is not limited thereto.

[0050] In addition, the aggregation monitoring device of Japanese Patent No. 6281534 is

[0051] “An aggregation monitoring device monitors the processing state of a liquid being subjected to aggregation treatment, characterized by comprising:

[0052] a measuring light irradiation unit for irradiating a measuring light to a measuring area of ​​the liquid to be processed;

[0053] a scattered light receiving unit for receiving scattered light generated by particles of the liquid to be processed in the measurement area; and

[0054] a measured value calculation unit, comprising an amplitude measuring mechanism for measuring the amplitude of the light receiving signal obtained by the scattered light receiving unit, monitoring and totaling the occurrence of the measured amplitude, calculating the generation rate or generation frequency of a specific amplitude, and calculating an index related to the aggregation of the treated liquid and indicating the particle size of flocs in the treated liquid,

[0055] The amplitude measuring mechanism detects a first inflection point where the light receiving signal changes from rising to falling and a second inflection point where the light receiving signal changes from falling to rising, and measures the amplitude based on a level difference between the first inflection point and the second inflection point.

[0056] An example of an aggregation processing device to which the aggregation state determination method according to the present embodiment can be applied has been described above.

[0057] <<Method for determining aggregation status>>

[0058] Next, the aggregation state determination method of the first embodiment of the present invention is described. The aggregation state determination method of this embodiment irradiates laser light into a liquid containing particles, and determines the aggregation state of the particles based on the light reception intensity of scattered light formed by the laser light being scattered by the particles, and as shown in FIG. Figure 3 As shown, it includes: a correlation acquisition step (step S11), acquiring the correlation between the particle size and the light receiving intensity change amplitude of the particles; and a determination step (step S12), determining the aggregation state of the particles based on the correlation.

[0059] The aggregation state determination method of this embodiment irradiates laser light into a liquid containing particles, and determines the aggregation state of the particles based on the light reception intensity of scattered light formed by the laser light being scattered by the particles. The irradiation of laser light, the reception of scattered light, and the calculation of the light reception intensity can be performed using known methods, for example, the aggregation state monitoring sensor 10 provided in the aggregation processing device can be used. The following describes the aggregation state determination method by taking the case of using the aggregation state monitoring sensor 10 as an example.

[0060] <Related acquisition step (step S11)>

[0061] In the correlation acquisition step, the correlation between the particle size and the magnitude of the change in the light receiving intensity is acquired. Figure 4 As shown in FIG. 1 , at a certain point in time, for example, there are five particles in the measurement area A. Figure 2 As shown, the laser light L irradiated to the measurement area A at the above time e Scattered by each particle, the scattered light L s The light is incident on the light receiving unit 103. At a time point after a predetermined time Δt has passed since the time point, the number of particles present in the measurement area A changes. Theoretically, there is a case where the number of particles does not change, but the particles perform Brownian motion and the treated liquid in the treatment tank 3 is stirred, so the number of particles usually changes. The predetermined time Δt is preferably a time selected from 0.1mSec to 10mSec, for example, about 1mSec.

[0062] When the number of particles changes, the intensity of scattered light changes in conjunction with the change, and the light receiving intensity of the scattered light at the light receiving unit 103 changes.

[0063] When the particle size is less than the diameter of the measurement area A, the larger the particle size, the greater the change in the light receiving intensity when a particle enters and leaves the measurement area A. Therefore, the size of the particle size entering and leaving the measurement area A can be detected based on the change in the light receiving intensity. That is, at any time t k The light receiving intensity and the time t after Δt k+1 The difference in the light receiving intensity becomes a value proportional to the surface area of ​​the particles entering and exiting the measurement area A during the above Δt period.

[0064] Figure 5A An example of the change in received light intensity over time is shown. Figure 5A The output signal in is the light receiving intensity of the light receiving unit 103, and the unit is, for example, mV.

[0065] Figure 5A It is drawn at time t1, time t2, ... time t z The light receiving intensity curve diagram measured at each time, the interval Δt (i.e. t k -t k-1 ) As described above, it is preferably 0.1mSec to 10mSec, for example 1mSec.

[0066] Figure 5B is Figure 5A The explanatory diagram includes the minimum points P1, P2, ... and the maximum points Q1, Q2, ... and the light receiving intensity variation range, that is, the difference h1, h2 between the minimum point and the maximum point. In the following, the number of maximum points may be referred to as the peak number.

[0067] As mentioned above, at any time t k-1 The light receiving intensity and time t k The difference in light receiving intensity h k is the same as at time t k-1 ~ time t k A value that is proportional to the surface area of ​​particles that enter and exit measurement area A during this period.

[0068] From time t1 to time t z The total light receiving intensity change amplitude h1, light receiving intensity change amplitude h2, and light receiving intensity change amplitude h of Δt×z seconds n In the detection at time t1 to time t z The particle size distribution of particles present in the vicinity of the measurement area A during this period. When z is set to 200, for example, and Δt=1 mSec, Δt×z becomes 0.2 seconds. However, this is just an example, and Δt×z may be about 0.01 seconds to 900 seconds.

[0069] Here, refer to Figure 6 to Figure 9 The relationship between the particle size and the variation range of the received light intensity will be described. The present inventors have studied the relationship between the particle size and the variation range of the received light intensity. Figure 6 This is a diagram for explaining the device used in the study of the relationship between the particle size and the variation range of the received light intensity. Figure 7 This is a graph showing the relationship between particle size and large peak occurrence rate obtained by studying the relationship between particle size and light receiving intensity variation range. The so-called large peak occurrence rate refers to the occurrence rate of peaks with a light receiving intensity variation range of 4000mV or more relative to the total number of peaks. Figure 8 , Fig. 9 This is a diagram for explaining the research conducted by the present inventors.

[0070] A treated liquid is prepared by adding black artificial particles to water in a concentration of 1.0% by weight on a dry weight basis. The artificial particles are prepared by adding a sodium alginate aqueous solution containing 1% by weight of a coating to a 1% by weight calcium chloride aqueous solution through a tube provided with a syringe at the front end and gelling. The addition rate of the sodium alginate aqueous solution is adjusted using a pulsation-free pump manufactured by TACMINA Co., Ltd. Artificial particles of 0.5 μm to 3.0 μm are prepared by changing the concentration of the sodium alginate aqueous solution, the addition rate, and the shape of the syringe.

[0071] like Figure 6 As shown, the treatment tank uses an inner diameter R of 154 mm and a bottom including a cone with an angle of θ=90° when viewed from the front. The treated liquid is stirred using a folding paddle type stirring blade including 4 blades inclined 45° relative to the horizontal plane. The diameter r of the stirring blade (the distance r between the front ends of the blades passing through the center of rotation) is 75 mm, and the distance between the upper end and the lower end of each blade is 10 mm. The stirring blade is arranged at the center of the treatment tank and the distance d from the upper end of the cone to the upper end of each blade is 45 mm.

[0072] A clustering state monitoring sensor (S.sensing CS-P manufactured by Kurita Industry Co., Ltd.) was placed on the top of the stirring blade, and 3 L of the treated liquid was supplied to the treatment tank. The diameter of the measuring area of ​​the probe included in the clustering state monitoring sensor is 1 mm. In addition, the stirring speed was set to 300 rpm, the analysis time was set to 3 minutes, the light receiving intensity was measured, and the large peak occurrence rate of each particle size of the artificial particles was calculated. In addition, the working ratio of the irradiated laser light was set to 10% (luminescence time 200 mSec, interruption time 1800 mSec). The results are shown in Figure 7 .

[0073] like Figure 7As shown, it can be seen that when the particle size is smaller than the diameter of the measurement area, the large peak appearance rate increases with the increase of the particle size, and when the particle size is larger than the diameter of the measurement area, the large peak appearance rate decreases with the increase of the particle size.

[0074] The present inventors and others explored the above research results in the following manner. Figure 8 As shown in FIG. 1 , when the particle size passing through the measurement area A is smaller than the diameter of the measurement area A, the larger the particle size, the larger the projection area of ​​the laser light, thus causing a large change in the amount of scattered light. As a result, the change in the amount of light received as the amount of scattered light received by the light receiving unit 103 also becomes larger. That is, there is a positive correlation between the particle size and the amplitude of the change in the light receiving intensity. On the other hand, Fig. 9 As shown, when the particle size of the particles passing through the measuring area A is larger than the diameter of the measuring area, the larger the particle size, the smaller the curvature of the particle surface, so that the scattering angle of the scattered light becomes smaller, and the scattered light reaching the light receiving unit 103 is reduced, thereby causing a small change in the amount of scattered light. As a result, the change in the amount of light received becomes smaller. That is, a negative correlation is shown between the particle size and the amplitude of the change in the light receiving intensity. Therefore, the correlation between the amplitude of the change in the light receiving intensity and the particle size of the particles passing through the measuring area A is reversed with the diameter of the measuring area as the boundary. Moreover, as described above, the correlation between the particle size and the amplitude of the change in the light receiving intensity can be determined by the relationship between the particle size and the beam diameter of the laser light. Moreover, the correlation shows a positive correlation when the particle size is less than the beam diameter, and a negative correlation when the particle size is greater than the beam diameter.

[0075] Specifically, when the particle size is less than the diameter of the measurement area A, Figure 5B In the figure, the light receiving intensity variation amplitude h1 indicates that a small-diameter particle is detected, the light receiving intensity variation amplitude h2 indicates that a large-diameter particle is detected, and the light receiving intensity variation amplitude h3 indicates that a particle with a diameter between these is detected. n This indicates that a particle that is somewhat larger than the particle h1 has been detected.

[0076] On the other hand, the case where the particle size is larger than the diameter of the measurement area A is opposite to the case where the particle size is smaller than the diameter of the measurement area A. Figure 5B In the figure, the received light intensity variation amplitude h1 indicates that a large-diameter particle is detected, the received light intensity variation amplitude h2 indicates that a small-diameter particle is detected, and the received light intensity variation amplitude h3 indicates that a particle with a diameter between these is detected. n This indicates that particles slightly smaller than the particles h1 have been detected.

[0077] Usually, before a certain dosage is reached, the more the dosage of the aggregating agent is added, the more aggregation proceeds and the larger the particle size. Therefore, in the relevant acquisition step, the amount of aggregating agent added to the treated liquid (dosage) is increased to obtain the change in the light receiving intensity. In the case where the amplitude of the light receiving intensity change increases with the increase in the dosage, the particle size is determined to be less than the diameter of the measuring area A, and it is determined that there is a positive correlation between the particle size in the treated liquid and the amplitude of the light receiving intensity change. On the other hand, in the case where the amplitude of the light receiving intensity change decreases with the increase in the dosage, the particle size is determined to be greater than the diameter of the measuring area A, and it is determined that there is a negative correlation between the particle size in the treated liquid and the amplitude of the light receiving intensity change. As described above, as long as the relationship between the dosage and the light receiving intensity is obtained, the correlation between the particle size and the amplitude of the light receiving intensity change can be obtained from the relationship.

[0078] <Determination step (step S12)>

[0079] In the determination step, the aggregation state of the particles is determined based on the correlation between the particle diameter and the width of the change in the received light intensity.

[0080] When there is a positive correlation between the particle size of the particles in the treated liquid and the amplitude of the change in the received light intensity, the measurement time range t1 to t z The amplitude of the light receiving intensity change of the aggregation state monitoring sensor is classified into levels in the order of small → large. By counting the number of peaks belonging to each level, the relative degree, that is, the degree (number of peaks) of each level in the total number of peaks, can be obtained, and the cumulative relative degree of the number of peaks can be obtained. At this time, as shown in Table 1, the larger the amplitude of the light receiving intensity change, the larger the particle size. On the other hand, in the case where there is a negative correlation between the particle size in the treated liquid and the amplitude of the light receiving intensity change, the measurement time range t1~t z The light receiving intensity variation amplitude of the aggregation state monitoring sensor in the image is classified into levels in the order of large → small. By counting the number of peaks belonging to each level, the relative degree, that is, the degree (peak number) of each level in the total number of peaks, can be obtained, and the cumulative relative degree of the peak number can be obtained. At this time, the smaller the light receiving intensity variation amplitude, the larger the particle size. In addition, the number of levels is preferably 2 or more, particularly preferably 3 or more, for example, 10 to 100.

[0081] [Table 1]

[0082]

[0083] As described above, the aggregation state of particles can be determined based on the correlation between the particle diameter and the amplitude of the change in the received light intensity. An example of the aggregation state determination method is described in further detail below.

[0084] (There is a positive correlation between the particle size in the treated liquid and the amplitude of the change in the light receiving intensity)

[0085] [Determination of the aggregation state based on the frequency of occurrence of the number of peaks exceeding a predetermined received light intensity variation width and the average received light intensity]

[0086] The aggregation state can be determined, for example, by the following method. In the case where there is a positive correlation between the particle size in the treated liquid and the light receiving intensity variation range, for example, if the frequency of the number of peaks above the prescribed light receiving intensity variation range (i.e., the relative degree) is above a preset threshold value (e.g., above 20%, or below 80% if converted to cumulative relative degree), the aggregation state is determined to be good. A specific example is described below.

[0087] Process 1

[0088] On the day when the aggregation condition is judged to be good by visual judgment, etc., the light receiving intensity change width h at the 80th percentile of the cumulative relative degree of the peak number is calculated. 80％ (Refer to Fig.10 ), and the average light receiving intensity. The average light receiving intensity is Fig.11 The area S of the region marked with diagonal lines (time-integrated value of light receiving intensity) is divided by the measurement time (t z -t1) obtained.

[0089] On multiple days when the gathering condition is good, perform step 1 and calculate the variation range h of the light receiving intensity on each day. 80％ value and average light receiving intensity.

[0090] Process 2

[0091] By calculating the light receiving intensity variation width h of each day in step 1 80％ The value and the average light receiving intensity are plotted as a curve, and the Fig.12 The amplitude of the received light intensity change h 80％ The correlation diagram between the average light receiving intensity and the average light receiving intensity is also determined. 80％ value) (y=ax+b).

[0092] Process 3

[0093] Substituting x in the relational expression y=ax+b determined in the above manner into the measured value of the average light receiving intensity at the time point of the dosage control, y, that is, h, is calculated. 80％ value, the calculated h 80％ The value is set as the “target light reception intensity variation width.” If the frequency of occurrence of the number of peaks greater than the “target light reception intensity variation width” is 20% or more (80% or less in terms of cumulative occurrence frequency), the focusing state is determined to be good.

[0094] In the above description, the preset threshold is set to 20% and the cumulative frequency of occurrence is set to 80%, but the above values ​​can be changed. For example, with respect to the threshold of 20%, the cumulative frequency of occurrence can be set to 70% or 50%, etc. These values ​​can be appropriately set within the range of finding the correlation. However, the threshold X% and the cumulative frequency of occurrence Y% are preferably values ​​close to 100 for X+Y.

[0095] Moreover, in Fig.12 In the example, the relational expression is a linear expression, but it can be a quadratic expression or other expressions as long as there is a correlation. Furthermore, a curve graph can be made and the result can be obtained based on the curve graph.

[0096] In the above description, the light reception intensity variation range information (light reception intensity variation range or a value corresponding thereto) is set to the light reception intensity variation range when the cumulative generation frequency is a predetermined value, but it is not limited thereto, and may be, for example, an average value, a central value, a first quartile, a third quartile, etc. of the light reception intensity variation range. When the light reception intensity variation range to be the average value or the central value is set as the “light reception intensity variation range information”, the target average light reception intensity range may be set based on the correlation between this information and the average light reception intensity.

[0097] In addition, an example of the relationship between the median value, the first quartile, the third quartile and the cumulative occurrence frequency of the light receiving intensity variation range is shown in Fig.13 .

[0098] In the description, the average light reception intensity is used as the light reception intensity information (light reception signal intensity or its corresponding value), but it is not limited to the average light reception intensity, and can also be the first quartile, median, third quartile, maximum value, or any other percentile.

[0099] When the peak height value (light reception intensity variation width) is correlated with the light reception intensity, the value corrected by the relational expression between the peak height value and the light reception signal intensity becomes constant regardless of the color or density of the measurement target sample.

[0100] [Other forms of determining the aggregation state]

[0101] In other forms of determining the aggregation state, the aggregation state can be determined based on the [average light receiving intensity change range] / [average light receiving intensity] obtained from the light receiving intensity of the aggregation state monitoring sensor. In the case, a first threshold value of [average light receiving intensity change range] / [average light receiving intensity] is set to avoid a particle size that is too small, and a second threshold value of [average light receiving intensity change range] / [average light receiving intensity] is set to avoid a particle size that is too large.

[0102] In order to obtain a curve diagram showing the relationship between [average light receiving intensity variation range] and [average light receiving intensity], as well as a first threshold and a second threshold, for example, an aggregation treatment device is set at a site, and an operator operates the aggregation treatment device for a specified period (for example, about 1 week to 1 month), and the actual drainage at the site is subjected to aggregation treatment. In the case, the operator observes the aggregation status while controlling the dosage based on experience, and records the time-dependent change of the signal intensity of the aggregation status monitoring sensor during this period. Furthermore, during the period, the [average light receiving intensity variation range] / [average light receiving intensity] when the aggregation state (particle size) becomes the lower limit of the appropriate range is obtained as the first threshold. Furthermore, during the period, the [average light receiving intensity variation range] / [average light receiving intensity] when the aggregation state (floc diameter) becomes the upper limit of the appropriate range is obtained as the second threshold.

[0103] If the aggregation state is determined based on [average light reception intensity change width] / [average light reception intensity], the aggregation state can be appropriately determined based on the light reception signal intensity of the aggregation state monitoring sensor even when the color and concentration of the particles are different.

[0104] (There is a negative correlation between the particle size in the treated liquid and the amplitude of the change in the light receiving intensity)

[0105] When there is a negative correlation between the particle size in the treated liquid and the amplitude of the light receiving intensity change, for example, if the frequency of the number of peaks above the specified amplitude of the light receiving intensity change (i.e., the relative degree) is below a predetermined threshold, the aggregation state is judged to be good.

[0106] Furthermore, when there is a negative correlation between the particle size in the liquid to be processed and the width of change in received light intensity, the aggregation state can also be determined by [average width of change in received light intensity] / [average received light intensity].

[0107] <<Aggregation processing method>>

[0108] Then, refer to Fig.14 , the aggregation processing method of the second embodiment of the present invention is described. Fig.14It is a flowchart showing the process of the aggregation processing method of the present embodiment. The aggregation processing method of the present embodiment is an aggregation processing method for adding an aggregating agent to a liquid containing particles to aggregate the particles, and includes: a determination process (step S1), irradiating laser light into the liquid containing particles, and determining the aggregation state of the particles based on the amplitude of the light receiving intensity change of the scattered light formed by the laser light being scattered by the particles; and an aggregating agent adding process (step S2), adding the aggregating agent in an amount based on the aggregation state of the particles determined in the determination process, and the determination process includes: a correlation acquisition step (step S11), acquiring the correlation between the particle size of the particles and the amplitude of the light receiving intensity change; and a determination step (step S12), determining the aggregation state of the particles based on the correlation. In the determination process in the aggregation processing method of the present embodiment, determination is performed by the aggregation state determination method of the first embodiment. Therefore, the description of the determination process is omitted here, and reference is made to Fig.15 , Fig.16 An example of the aggregating agent adding step will be described in detail. Fig.15 : is a flowchart showing the flow of the first aggregating agent adding step in this embodiment. Fig.16 : is a flowchart showing the flow of the second aggregating agent adding step in this embodiment.

[0109] <Aggregating agent adding step (step S2)>

[0110] (First aggregating agent adding step)

[0111] The first aggregating agent adding step is a step for adding an aggregating agent when the aggregation state is determined based on the frequency of the number of peaks with a predetermined light receiving intensity variation range and the average light receiving intensity in the determination step. In the first aggregating agent adding step, the aggregating agent is added until the frequency of the number of peaks with a predetermined light receiving intensity variation range becomes greater than the threshold. For example, h calculated from x in the above relationship y=ax+b is set to 80％ The value is taken as the “target light reception variation width”, and the amount of the aggregating agent added is controlled so that the frequency of occurrence of the number of peaks exceeding the “target light reception variation width” becomes 20% or more (80% or less in terms of cumulative occurrence frequency).

[0112] In detail, first, Fig.15As shown, an aggregating agent is added to the treatment tank in which the treated liquid is being stirred (step S21). The aggregating agent may be added continuously in small amounts, or the required additive amount may be added once or in several times. Subsequently, it is determined whether the frequency of the number of peaks above the target light receiving intensity variation amplitude is above a specified threshold. The determination is performed, for example, by the controller 8. When the frequency of the number of peaks above the target light receiving intensity variation amplitude is above a specified threshold (step S22 / yes (YES)), stirring is stopped, the treated liquid is discharged from the treatment tank and the aggregation treatment process is terminated. On the other hand, when the frequency of the number of peaks above the target light receiving intensity variation amplitude is less than the specified threshold (step S22 / no (NO)), the addition of the aggregating agent is continued, and when the aggregating agent is insufficient, the output of the dosing device (pump stroke, pump pulse, rotation speed, etc.) is increased, and when the aggregating agent is excessive, the output of the dosing device is reduced.

[0113] As described above, the amount of the aggregating agent added can be controlled so that the particle size falls within an appropriate range.

[0114] (Second Aggregating Agent Adding Step)

[0115] The second aggregating agent adding step is a step for determining the aggregation state based on [average light receiving intensity variation range] / [average light receiving intensity]. In the second aggregating agent adding step, the aggregating agent is added in such a way that [average light receiving intensity variation range] / [average light receiving intensity] is greater than the first threshold value, and in order to prevent the aggregated particles from becoming too large, the aggregating agent is added in such a way that [light receiving intensity variation range] / [average light receiving intensity] becomes less than the second threshold value (greater than the first threshold value).

[0116] In detail, first, Fig.16 As shown, an aggregating agent is added to the treatment tank where the treated liquid is being stirred (step S23). The aggregating agent is preferably added continuously in small amounts. Then, it is determined whether the [average light receiving intensity variation range] / [average light receiving intensity] value is above the first threshold value (step S24). The determination is performed, for example, by the controller 8. When the [average light receiving intensity variation range] / [average light receiving intensity] value is above the first threshold value (step S24 / yes), stirring is stopped, the treated liquid is discharged from the treatment tank and the aggregation treatment process is terminated. On the other hand, when the [average light receiving intensity variation range] / [average light receiving intensity] value is less than the first threshold value (step S24 / no), the addition of the aggregating agent continues, and when the aggregating agent is insufficient, the output (pump stroke, pump pulse, rotation speed, etc.) of the dosing device is increased, and when the aggregating agent is excessive, the output of the dosing device is reduced. In addition, when the [average light receiving intensity variation range] / [average light receiving intensity] value exceeds the second threshold value, the aggregating agent addition process is also terminated in the above case because the particle size is too large.

[0117] By controlling the addition of aggregating agents based on [average light receiving intensity change range] / [average light receiving intensity], even when the color and concentration of the particles are different, the addition of aggregating agents can be appropriately controlled based on the light receiving signal intensity of the aggregation state monitoring sensor (which can be considered as a particle size measurement value corrected based on the color and concentration of the particles).

[0118] (There is a negative correlation between the particle size in the treated liquid and the amplitude of the change in the light receiving intensity)

[0119] In the case where there is a negative correlation between the particle size in the treated liquid and the light receiving intensity variation range, for example, if the frequency of the number of peaks above the prescribed light receiving intensity variation range (i.e., the relative degree) is below a preset threshold value, it is determined that the aggregation state is good. And, the amount of the aggregating agent added can be controlled in such a way that the frequency of the number of peaks above the prescribed light receiving intensity variation range becomes below the threshold value.

[0120] Furthermore, when there is a negative correlation between the particle size in the liquid to be processed and the width of change in received light intensity, the amount of aggregating agent added can also be controlled by [width of change in average received light intensity] / [average received light intensity].

[0121] The present invention has been described above based on the embodiments of the present invention, but the present invention is not limited thereto. The above is ultimately an example, and those having substantially the same structure and exerting the same effects as the technical ideas described in the claims of the present invention are all included in the technical scope of the present invention.

[0122] For example, the above-mentioned aggregation processing device is only an example. Figure 1 In the embodiment, the controller 8 and the aggregation state monitoring sensor 10 are separately provided, but the control program of the controller 8 may be loaded into the signal processing unit of the aggregation state monitoring sensor 10, so that the aggregation state monitoring sensor 10 provides a control signal to the dosing device 4.

[0123] Furthermore, the aggregation state monitoring sensor 10 may be provided in the aggregation liquid outflow pipe from the treatment tank 3. Furthermore, a measurement tank for the liquid introduced into the treatment tank 3 may be provided, and the aggregation state monitoring sensor 10 may be provided in the measurement tank.

[0124] Moreover, in the above probe, the light emitting unit 102 and the light receiving unit 103 are orthogonal to each other, but the present invention is not limited thereto, and the light emitting unit 102 and the light receiving unit 103 may also be arranged to form other angles. The angle formed by the light emitting unit 102 and the light receiving unit 103 may be set to be greater than 10° and less than 170°, for example.

[0125] Furthermore, the use time of the light emitting component can be extended by repeating the light emission and non-light emission at a predetermined time interval. For example, when the light emission time is set to 0.2 seconds / time and the light emission interval is set to 2 seconds, the use time (lifespan) of the light emitting component can be extended to 10 times compared to the case of continuous light emission.

[0126] Furthermore, the above-mentioned example of the aggregating agent adding step is merely an example, and the aggregating agent may be added based on the aggregation state determined by the aggregation state determination method of the present invention.

[0127] [Explanation of Symbols]

[0128] 3: Processing tank

[0129] 4: Dosing device

[0130] 8: Controller

[0131] 10: Aggregation status monitoring sensor

Claims

1. A method for determining an aggregation state, comprising irradiating a laser light into a liquid containing particles, and determining the aggregation state of the particles based on a variation amplitude of a light receiving intensity of scattered light formed by scattering the laser light by the particles, and comprising: A correlation acquisition step, acquiring the correlation between the particle size of the particles and the amplitude of the change in the light receiving intensity; and A determination step is performed to determine the aggregation state of the particles based on the correlation.

2. The aggregation state determination method according to claim 1, wherein in the correlation acquisition step, the relationship between the amount of aggregating agent added and the amplitude of the light receiving intensity change is acquired, and the correlation between the particle size and the amplitude of the light receiving intensity change is acquired from the relationship.

3. The aggregation state determination method according to claim 1 or 2, wherein the correlation between the particle diameter and the light receiving intensity variation amplitude is determined by the relationship between the particle diameter and the beam diameter of the laser light. 4 . The aggregation state determination method according to claim 3 , wherein the correlation shows a positive correlation when the particle size is less than the beam diameter, and shows a negative correlation when the particle size is greater than the beam diameter.

5. An aggregation treatment method, which is an aggregation treatment method for adding an aggregating agent to a liquid containing particles to aggregate the particles, and comprises: a determination step of irradiating laser light into the liquid and determining the aggregation state of the particles based on a variation amplitude of a light reception intensity of scattered light resulting from scattering of the laser light by the particles; and an aggregating agent adding step of adding the aggregating agent in an amount based on the aggregation state of the particles determined in the determining step, The determination process includes: a correlation acquisition step of acquiring a correlation between the particle size of the particles and the light receiving intensity change range; and a determination step of determining the aggregation state of the particles based on the correlation.

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