Aggregation state determination method and aggregation processing method

Abstract

This aggregation state determination method is a method in which laser light is irradiated into a liquid containing particles, and the aggregation state of the particles is determined on the basis of the light reception intensity of scattered light obtained by scattering the laser light by the particles. And determines the aggregation state of the particles on the basis of the value of a variation index indicating the variation in the light reception intensity.

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. 2022-116996 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 aggregation index can be generated based on the amplitude (variation amplitude) of the received signal intensity of scattered light obtained by the aggregation monitoring device using the scattered light in the treated liquid, and the particle size distribution state of the aggregated particles can be estimated. Moreover, according to the technology described in Patent Document 1, it is believed that the excess or insufficiency 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 the correlation between the particle size of aggregated flocs and the aggregation index generated by the amplitude of the light receiving signal intensity is the relationship with the physical measurement area of ​​the aggregation monitoring device using scattered light in water, and there is a situation where the aggregation index changes. That is, the relationship between the required dosage and the aggregation index is not the same, and there is a situation where the dosage is judged to be insufficient even if the dosage is excessive. In other words, there is a situation where the actual particle size is large but the particle size is judged to be small. As a result, the control of the dosage is unstable, and there is a situation where excessive aggregating agent is continuously added.

[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 determining the aggregation state of particles in a treatment liquid in a wide range of particle diameters.

[0015] [Technical means to solve the problem]

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

[0017] [1] A first form of a method for determining an aggregation state of the present invention is to irradiate laser light into a liquid containing particles, determine the aggregation state of the particles based on the light reception intensity of scattered light resulting from scattering of the laser light by the particles, and determine the aggregation state of the particles based on a variation index indicating a variation in the light reception intensity.

[0018] [2] In the focusing state determination method described in [1], the variation index may be a light receiving amount variation index CI represented by equation (1).

[0019] [Number 1]

[0020]

[0021] In the formula (1),

[0022] S i : The integral value of the light receiving intensity in the i-th floc formation state measurement time domain

[0023] S ave : an average value of the integrated value of the light reception intensity in the floc formation state measurement time domain when the light reception intensity is acquired n times in the floc formation state measurement time domain.

[0024] [3] In the aggregation state determination method described in [1] or [2], when the variation index is above a first threshold value and below a second threshold value which is a value larger than the first threshold value, the aggregation state can be determined to be good.

[0025] [4] In the aggregation state determination method described in any one of [1] to [3], the aggregation state of the particles can be determined based on the relationship between the particle size of the particles and the variation range of the light receiving intensity in addition to the variation index.

[0026] [5] In the aggregation state determination method described in any one of [1] to [4], the relationship between the variation index and the particle size can be acquired in advance, and the determination based on the variation index can be performed within the particle size range determined based on the relationship.

[0027] [6] Furthermore, another form of the aggregation processing method of the present invention is an aggregation processing method in which an aggregating agent is added 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 a variation index representing a variation in the light receiving 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 determination step.

[0028] [7] In the focusing processing method described in [6], the variation index may be a light receiving amount variation index value CI expressed by equation (2).

[0029] [Number 2]

[0030]

[0031] In the formula (2),

[0032] S i : The integral value of the light receiving intensity in the i-th floc formation state measurement time domain

[0033] S ave : an average value of the integrated value of the light reception intensity in the floc formation state measurement time domain when the light reception intensity is acquired n times in the floc formation state measurement time domain.

[0034] [8] In the aggregation processing method described in [6] or [7], when the change index is less than a first threshold, the amount of the aggregating agent added can be increased, and when the change index exceeds a second threshold that is a value larger than the first threshold, the amount of the aggregating agent added can be reduced.

[0035] [9] In the aggregation processing method described in [8], after the change index exceeds the second threshold, when a third threshold is reached that is a value greater than the first threshold and smaller than the second threshold, the reduction in the amount of the aggregating agent added can be stopped.

[0036] Effects of the Invention

[0037] According to the above aspect of the present invention, the aggregation state of particles in the liquid to be processed can be determined in a wide range of particle diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] [ 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.

[0039] [ Figure 2 ] is a structural diagram showing an example of the structure of a probe included in an aggregation state monitoring sensor.

[0040] [ Figure 3 ] is a schematic diagram of the measurement area of ​​the aggregation status monitoring sensor.

[0041] [ Figure 4A ] is a diagram showing an example of a detection waveform obtained using an aggregation state monitoring sensor.

[0042] [ Figure 4B] is a diagram showing an example of a detection waveform obtained using an aggregation state monitoring sensor.

[0043] [ Figure 5 ] is a diagram illustrating an apparatus used to study the relationship between particle size and the amplitude of change in received light intensity.

[0044] [ Figure 6 ] is a curve graph showing the relationship between particle size and large peak appearance rate.

[0045] [ Figure 7 ] is a diagram used to illustrate the research conducted by the inventors of the present invention.

[0046] [ Figure 8 ] is a diagram used to illustrate the research conducted by the inventors of the present invention.

[0047] [ Fig. 9 ] is a diagram used to illustrate the passage pattern and scattering direction of scattered light when particles having a particle size larger than the diameter of the measuring area A pass through the measuring area A.

[0048] [ Fig.10 ] is a diagram used to illustrate the area of ​​the detection waveform diagram representing the temporal variation of the light receiving intensity.

[0049] [ Fig.11 ] is the index of particle size and light receiving amount variation CI (3) A graph showing an example of the relationship between .

[0050] [ Fig.12 ] is a flowchart showing the process of the aggregation processing method of the second embodiment of the present invention.

[0051] [ Fig.13A ] is a graph showing the temporal change in the output of the polymer aggregating agent in the example.

[0052] [ Fig. 13B ] is the light receiving amount variation index CI (3) A graph showing the time-varying changes of . DETAILED DESCRIPTION

[0053] <<Configuration example of aggregation processing device>>

[0054] 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.

[0055] like Figure 1As 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.

[0056] The aggregating agent may be an inorganic aggregating agent or an organic aggregating agent, or these may be used in combination.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In addition, the aggregation monitoring device of Japanese Patent No. 6281534 is

[0063] “An aggregation monitoring device monitors the processing state of a liquid being subjected to aggregation treatment, characterized by comprising:

[0064] a measuring light irradiation unit for irradiating a measuring light to a measuring area of ​​the liquid to be processed;

[0065] a scattered light receiving unit for receiving scattered light generated by particles of the liquid to be processed in the measurement area; and

[0066] 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,

[0067] 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.

[0068] 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.

[0069] <<Method for determining aggregation status>>

[0070] 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, 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 determines the aggregation state of the particles based on the value of a variation index indicating the variation of the light reception intensity.

[0071] 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 the laser light, the reception of the scattered light, and the calculation of the light reception intensity can be performed using a known method, 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.

[0072] In this embodiment, the light receiving intensity is acquired by the aggregation state monitoring sensor 10. Figure 3 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.

[0073] 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 by the light receiving unit 103 changes.

[0074] 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.

[0075] Figure 4A An example of the change in received light intensity over time is shown. Figure 4A The output signal in is the light receiving intensity of the light receiving unit 103, and the unit is, for example, mV.

[0076] Figure 4A 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.

[0077] Figure 4B is Figure 4A 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.

[0078] 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.

[0079] 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.

[0080] Here, refer to Figures 5 to 8 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 5 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 6 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 7 , 8 This is a diagram for explaining the research conducted by the present inventors.

[0081] A simulated treated liquid was prepared by dispersing black artificial particles in water at a concentration of 1.0 wt% on a dry weight basis. The artificial particles were prepared by adding a sodium alginate aqueous solution containing 1 wt% of a coating to a 1 wt% 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 was adjusted using a pulsation-free pump manufactured by TACMINA Co., Ltd. Artificial particles of 0.5 μm to 3.0 μm were manufactured by changing the concentration of the sodium alginate aqueous solution, the addition rate, and the shape of the syringe.

[0082] like Figure 5 As shown, the treatment tank uses an inner diameter R of 154mm and a bottom including a cone with an angle of θ=90° in front view. The stirring of the simulated treated liquid uses 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 75mm, and the distance between the upper end and the lower end of each blade is 10mm. 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 45mm.

[0083] 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 6 .

[0084] like Figure 6 As 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.

[0085] The present inventors and others explored the above research results in the following manner. Figure 7 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. On the other hand, Figure 8As shown, when the particle size of the particles passing through the measurement area A is larger than the diameter of the measurement 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. As a result, the correlation between the amplitude of the change in the light receiving intensity and the particle size of the particles passing through the measurement area A is reversed with the diameter of the measurement area as the boundary.

[0086] and, Fig. 9 FIG. 1 is a diagram for explaining the passing pattern and the scattering direction of scattered light when a particle having a particle diameter larger than the diameter of the measurement area A passes through the measurement area A. Fig. 9 In the case of the portion on the opposite side of the light receiving unit 103 in the measurement area A shown in (A), the angle formed by the direction of the laser light irradiated from the light emitting unit 102 and the scattering direction of the scattered light is small, so the amount of scattered light received by the light receiving unit 103 is reduced. As a result, the light reception intensity generated by the light receiving unit 103 becomes smaller. In other words, the peak height of the detection waveform becomes lower.

[0087] When the particles pass through Fig. 9 In the case of the entire measurement area A shown in (B), scattered light tends to flow toward the light receiving unit 103, so the amount of scattered light received by the light receiving unit 103 increases. As a result, the light reception intensity generated by the light receiving unit 103 increases. In other words, the peak height of the detection waveform increases.

[0088] In a part of the particle, Fig. 9 In the case of the portion on the light receiving unit 103 side in the measurement area A shown in (C), the scattered light is directed in the opposite direction to the light receiving unit 103, and therefore the light receiving unit 103 does not receive the scattered light. As a result, the detection waveform does not show a peak.

[0089] As described above, the passing pattern of particles when passing through the measurement region A changes the projection area of ​​laser light or the scattering direction of scattered light, and therefore it is considered that the detection waveform is non-uniform.

[0090] The inventors of the present invention have conducted further research and found that the light receiving amount variation index CI is an index that can be used to determine the size of the particle size even if the particle size changes before and after the diameter of the measurement area. (3) "Light reception variation index CI (3) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by S1~S n The average value S ave The obtained statistics are expressed as the following formula (3). The integral value of the light receiving intensity corresponds to Fig.10The area represented by the shaded area of ​​? The floc formation state measurement time domain is the time when the laser light is irradiated to the measurement area A each time (the light emission time of one pulse).

[0091] [Number 3]

[0092]

[0093] Will be obtained through Figure 6 The light receiving amount variation index CI is calculated based on the data obtained from the research results. (3) The relationship between the particle size and Fig.11 . Fig.11 CI is an index that indicates the change in particle size and light reception (3) The following is a graph showing an example of the relationship between Fig.11 As shown in the figure, it can be seen that the larger the particle size, the greater the light receiving amount variation index CI (3) The higher it goes.

[0094] Therefore, by using the light receiving amount variation index CI (3) , it is possible to determine the aggregation state in the treated liquid. Specifically, as shown in Table 1, it is determined as the light receiving amount variation index CI (3) The larger the particle size, the larger the particle size.

[0095] [Table 1]

[0096]

[0097] 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.

[0098] The determination of the focusing state can be performed, for example, by the following method. (3) If the light receiving amount variation index CI is greater than a preset first threshold value and less than a second threshold value which is greater than the first threshold value, the focusing state is determined to be good. (3) If the first threshold is not reached, it can be judged that the aggregation is insufficient and the particle size is too small. (3) If the particle size exceeds the second threshold, it can be determined that the particle size is too large.

[0099] In order to obtain the first threshold value and the second threshold value, for example, the liquid to be treated is subjected to aggregation treatment for a predetermined period (e.g., about 1 week to 1 month) by means of an aggregation treatment device. At this time, the dosage is adjusted while observing the aggregation state, and the time-dependent change of the light receiving intensity of the aggregation state monitoring sensor is recorded. In addition, the light receiving intensity change index CI when the particle size reaches the lower limit of the appropriate range during the period is calculated. (3) The light receiving amount variation index CI when the particle size is at the upper limit of the appropriate range is set as the first threshold value.(3) Set as the second threshold.

[0100] <<First Modification of Aggregation State Determination Method>>

[0101] The above-mentioned focusing state determination method includes the following steps: (3) The clustering processing method of the present embodiment is preferably a method for determining the light receiving amount variation index CI. (3) In addition to the light reception intensity variation index CI, the light reception intensity variation index CI is used to determine the variation of the particle size. (3) In addition, the determination based on the variation range of the light receiving intensity of scattered light can more accurately determine the aggregation state. In addition, the determination based on the variation range of the light receiving intensity of scattered light is, for example, the determination of the aggregation state using the relationship between the particle size and the variation range of the light receiving intensity.

[0102] <<Second Modification of Aggregation State Determination Method>>

[0103] In addition, the light receiving amount variation index CI can be acquired in advance (3) The relationship with the particle size is used to perform CI based on the light receiving amount variation index within the particle size range determined based on the relationship. (3) Thus, the determination within the determined particle size range will not be complicated, and the aggregation state can be accurately grasped.

[0104] <<Third Modification of Aggregation State Determination Method>>

[0105] The above-mentioned focusing state determination method is a focusing processing method in which the first threshold value and the second threshold value are set, but the focusing processing method of the present embodiment may also be a focusing processing method in which only either the first threshold value or the second threshold value is set. In this case, in addition to performing the light reception amount variation index CI (3) In addition to the above-mentioned determination based on the amplitude of the change in the light receiving intensity of scattered light, the determination can also be performed.

[0106] Normally, the particle concentration of the treated liquid supplied during the aggregation process does not change significantly, but there are cases where the particle concentration changes temporarily. For example, when the particle concentration of the treated liquid decreases temporarily, the aggregation dose per unit particle concentration will increase. At this time, the particle size tends to increase before the particle concentration decreases. In the case of making a judgment based on the amplitude of the light receiving intensity change of the scattered light, if the particle size is larger than the diameter of the measuring area, the amplitude of the light receiving intensity change becomes smaller, so in the judgment based only on the amplitude of the light receiving intensity change, there is a case where the accurate judgment of the aggregation state becomes insufficient. However, since the particle size and the coefficient of variation of the light receiving amount are positively correlated within a large range, in addition to making a judgment based on the amplitude of the light receiving intensity change, a light receiving amount change index CI based on a second threshold value is also made. (3) The determination of the aggregation state can be accurately made.

[0107] In the aggregation process, if the particle size is not assumed to be larger than the diameter of the measurement area, the light receiving amount variation index CI is calculated based on the first threshold value. (3) The judgment can prevent the aggregation from becoming insufficient.

[0108] <<Aggregation processing method>>

[0109] Next, the aggregation processing method of the second embodiment of the present invention is described. The aggregation processing method of this embodiment is an aggregation processing method for adding an aggregation agent to a liquid containing particles to aggregate the particles, and includes: a determination step of irradiating laser light into the liquid, and calculating a light reception amount variation index CI based on the light reception intensity of scattered light formed by the laser light being scattered by the particles and calculated by formula (3) (3) Determining the aggregation state of the particles; and adding an aggregating agent in an amount based on the aggregation state of the particles determined in the determining step. Fig.12 An example of a specific flow of the clustering processing method according to this embodiment will be described. Fig.12 This is a flowchart showing the flow of the clustering processing method according to this embodiment.

[0110] First, the supply of the aggregating agent to the treatment tank in which the treated liquid is being stirred is started (step S1). At this time, the treated liquid is continuously supplied to the treatment tank.

[0111] Then, the light reception intensity is continuously calculated, and the light reception amount variation index CI is calculated from the calculated light reception intensity. (3) , determine the light reception variation index CI (3) Is it greater than the first threshold (step S2).

[0112] CI of the light receiving amount variation index (3)If the first threshold value is not reached (step S2 / NO), the dosage (dosing speed) is increased (step S3). When the dosage is increased, the output (pump stroke, pump pulse, rotation speed, etc.) of the dosing device is increased. Thereafter, the addition of the aggregating agent is continued with the increased dosage. In other words, the steps after step S1 are implemented. On the other hand, when the light receiving amount variation index CI (3) When the light receiving amount variation index CI is equal to or greater than the first threshold value (step S2 / yes), the light receiving amount variation index CI is determined. (3) Is it below the second threshold (step S4).

[0113] CI of the light receiving amount variation index (3) When the second threshold value is exceeded (step S4 / No), the dosing device 4 reduces the dosing amount (dosing speed) (step S5). When the dosing amount is reduced, the output of the dosing device is reduced. Thereafter, the addition of the aggregating agent is continued at the reduced dosing amount. In other words, the steps after step S1 are implemented.

[0114] CI of the light receiving amount variation index (3) When the temperature is below the second threshold value (step S4 / yes), it is determined whether to end the addition of the treated liquid (step S6). When the addition of the treated liquid is ended (step S6 / yes), the addition of the aggregating agent is ended, and the aggregation process is ended. On the other hand, when the addition of the treated liquid is continued (step S6 / no), the addition of the aggregating agent is continued without changing the agent addition speed, and the steps after step S1 are repeated in sequence.

[0115] <<Modification of the aggregation processing method>>

[0116] In the focusing processing method of this embodiment, the light receiving amount variation index CI (3) After exceeding the second threshold, when reaching a third threshold which is a value larger than the first threshold and smaller than the second threshold, it is preferable to stop reducing the dosage. (3) If the reduction of the dosage is stopped at the stage where the second threshold value decreases to the first threshold value, the dosage may become too small and the aggregation of particles may become insufficient. (3) When the second threshold is exceeded and the third threshold value, which is a value larger than the first threshold value and smaller than the second threshold value, is reached, the reduction of the amount of the added drug is stopped, and the amount of the added drug does not become too small, and the aggregation can continue.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] Furthermore, the use time of the light emitting element 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 element can be extended to 10 times compared to the case of continuous light emission.

[0122] 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.

[0123] <<Other Modifications>>

[0124] In the above-mentioned focusing state determination method and focusing processing method, the variation index uses the light receiving amount variation index CI represented by the above-mentioned formula (3): (3) However, the light receiving amount variation index CI expressed by the following equations (4) to (8) can also be used: (4) ~CI (8) .

[0125] Light receiving amount variation index CI (4) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by the unbiased standard deviation of S1~S n The average value S ave The obtained statistics are expressed as the following formula (4).

[0126] [Number 4]

[0127]

[0128] Light receiving amount variation index CI (5) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by the absolute deviation of S1~S n The average value S ave The obtained statistics are expressed as the following formula (5).

[0129] [Number 5]

[0130]

[0131] Light receiving amount variation index CI (6) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by the standard deviation of S1 to S n The average value S ave The obtained statistics are expressed as the following formula (6).

[0132] [Number 6]

[0133]

[0134] In the above formulas (4) to (6),

[0135] S i : The integral value of the light receiving intensity in the time domain of the i-th floc formation state measurement

[0136] S ave : The average value of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is acquired n times in the floc formation state measurement time domain.

[0137] Light receiving amount variation index CI (7) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by the central absolute deviation of the 50百分点 The obtained statistics are expressed as the following formula (7).

[0138] [Number 7]

[0139]

[0140] Light receiving amount variation index CI (8) is the integrated value of the light receiving intensity when n times are taken in the floc formation state measurement time domain (area S i ) divided by the central standard deviation of the median value S 50百分点 The obtained statistics are expressed as the following formula (8).

[0141] [Number 8]

[0142]

[0143] In the above formulas (7) to (8),

[0144] S i : The integral value of the light receiving intensity in the time domain of the i-th floc formation state measurement

[0145] S 50百分点 : The central value (50 percentile value) of the integrated value of the light reception intensity in the floc formation state measurement time domain when the light reception intensity is acquired n times in the floc formation state measurement time domain.

[0146] Furthermore, as long as the variation index can be correlated with the particle size, the reference point (S ave , S 50百分点 ) can be changed to the first quartile, the median, the third quartile, the maximum value, or any other percentile. In addition, it is also possible to use a statistic obtained by multiplying the above-mentioned formulas (3) to (8) by an arbitrary coefficient, a statistic calculated without dividing by the mean value or the median, or a statistic obtained by multiplying at least one of the numerator and the denominator by the above value.

[0147] Example

[0148] The following are examples of the present invention, but the conditions in the examples are examples of conditions used to confirm the feasibility and effect of the present invention, and the present invention is not limited to the conditions used in the following examples. As long as the purpose of the present invention is achieved without departing from the gist of the present invention, the present invention can adopt various conditions.

[0149] <Example 1>

[0150] Comparison of the correlations between a plurality of variation indices and particle sizes was performed.

[0151] A simulated treated liquid was prepared in which black artificial particles were dispersed in water in a concentration of 1.0% by weight on a dry weight basis. The artificial particles were prepared by adding an aqueous sodium alginate solution containing 1% by weight of a coating to a 1% by weight calcium chloride aqueous solution through a tube having a syringe at the front end and gelling the solution. The rate of addition of the aqueous sodium alginate solution was adjusted using a pulsation-free pump manufactured by TACMINA Co., Ltd. Artificial particles having an average particle size and a weight ratio at each particle size as shown in Table 2 were manufactured by changing the concentration of the aqueous sodium alginate solution, the rate of addition, and the shape of the syringe. Thus, the simulated treated liquid containing each artificial particle was adjusted for the artificial particles of conditions No. 1 to No. 8.

[0152] [Table 2]

[0153]

[0154] like Figure 5 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.

[0155] A aggregation state monitoring sensor (S.sensing CS-P manufactured by Kurita Industry Co., Ltd.) is arranged on the upper part of the stirring blade, and 3L of the treated liquid is supplied to the treatment tank. The diameter of the measuring area of ​​the probe included in the aggregation state monitoring sensor is 1mm. In addition, the stirring speed is set to 300rpm, the analysis time is set to 3 minutes, the light receiving intensity is measured, and the large peak occurrence rate of each particle size of the artificial particles is calculated. In addition, the working ratio of the irradiated laser light is set to 10% (luminescence time 200mSec, interruption time 1800mSec). The above test was carried out for the simulated treated liquids of conditions No. 1 to No. 8 respectively.

[0156] The statistical quantities represented by the calculation formulas [1] to [6] shown in Table 3 were used as the variation index, and the determination coefficient R representing the correlation between each variation index and the particle size was calculated. 2 In the calculation formulas shown in Table 3, for S i Substitute the integrated value of the light receiving intensity in the time domain of the i-th floc formation state measurement into S. α It is the reference point for calculating each change index. α Substitute the average value of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain, the minimum value of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain, each percentile of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain, or the maximum value of the integrated value of the light receiving intensity in the floc formation state measurement time domain. Substitute different S in each calculation formula [1] to [6] α The calculated coefficient of determination R 2 Shown in Table 3.

[0157]

[0158] Under the test conditions in Example 1, as shown in Table 3, in the calculation formula [3], S α Substitute the minimum value S of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain. min In the case of (min in Table 4), the determination coefficient R 2 Less than 0.80, the correlation is low compared to other cases. α Substitute the 95th percentile S of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain. 95百分点 In the case of 2 Less than 0.80, the correlation is low compared to other cases. α Substitute the maximum value S of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain. max In the case of 2 Less than 0.80, the correlation is low compared to other cases. α Substitute the maximum value S of the integrated value of the light receiving intensity in the floc formation state measurement time domain when the light receiving intensity is obtained n times in the floc formation state measurement time domain. max In the case of 2 If the correlation is less than 0.80, it is lower than that in other cases. However, in other cases, the calculation formulas [1] to [6] have a generally good relationship (R 2 ≧0.80). That is, by appropriately selecting the variation index and the reference point S for calculating the variation index, α , which can determine the aggregation state of particles in the treated liquid over a wide range of particle sizes.

[0159] In terms of analyzing sample data by intermittent measurement using a focusing sensor, and in terms of easy-to-understand calculation using arithmetic mean without using percentage points, it is preferable to use the reference point S in calculation formula [2] and calculation formula [5] in Table 3. α Application ave In the calculation formula [2] and [5] in Table 3, the reference point S α Application ave In the change index, the reference point S in the calculation formula [2] is α Application ave Therefore, it is more preferable to use the reference point S in the calculation formula [2]α Application ave However, if the determination coefficient R 2 If the determination coefficient R is 0.80 or more, the aggregation state of particles in the treated liquid can be determined in a wide range of particle sizes using any of the statistics shown in Table 3. 2 If the value is greater than 0.80, the calculation formulas [1] to [6] may use a statistic obtained by multiplying an arbitrary coefficient, a statistic calculated without dividing by the mean value or median value, or a statistic obtained by multiplying at least one of the numerator and denominator by the above value.

[0160] <Example 2>

[0161] The treated liquid with a suspended solids (SS) content of 0.8% was fed at a speed of 23 m / s. 3 / h is supplied to the treatment tank, and the aggregating agent is continuously added to the treated liquid in the treatment tank. The aggregating agent uses both an inorganic aggregating agent and a polymer aggregating agent. The inorganic aggregating agent uses polyferric sulfate, and its concentration is set to 1432 mg / L, and the addition rate relative to the amount of suspended matter is set to 18.2% / SS. The addition rate of the inorganic aggregating agent is set to the ratio of the dry weight of the inorganic aggregating agent to the weight of the suspended matter (unit % / SS). The polymer aggregating agent uses a copolymer with 2-(methacryloyloxy)ethyl (trimethyl) ammonium chloride, 2-(acryloyloxy)ethyl (trimethyl) ammonium chloride, acrylic acid, and acrylamide as structural units as an amphoteric polymer aggregating agent. In addition, 2-(methacryloyloxy)ethyl (trimethyl) ammonium chloride and 2-(acryloyloxy)ethyl (trimethyl) ammonium chloride are cationic monomers, acrylic acid is an anionic monomer, and acrylamide is a non-ionic monomer. The dosing output of the polymer aggregating agent is intentionally changed.

[0162] The light receiving intensity was continuously measured using a focusing state monitoring sensor (S.sensing CS-P manufactured by Kurita Industry Co., Ltd.) and the light receiving amount variation index CI was calculated. (3) .

[0163] Fig.13A The time-dependent changes in the output of the polymer aggregating agent are shown in FIG. Fig. 13B The light receiving amount variation index CI is shown in (3) changes over time.

[0164] From time T0 to time T1, if Fig. 13B As shown in the figure, the light receiving amount variation index CI (3) At time T1 and time T2, the polymer aggregating agent dosing output is set to 26% and 30%, respectively. Fig.13AAs shown, there is a time lag between the time T1 and time T2 when the dosing output is changed and the actual dosing change. (3) When the concentration reaches 25%, the polymer aggregating agent output is reduced by proportional-integral-differential (PID) control. Fig. 13B As shown in the light receiving amount variation index CI (3) After reaching 20% ​​at time T3, the light receiving amount variation index CI (3) The output of the polymer aggregating agent is controlled in such a way that it becomes 15%. CI, the index of light receiving amount variation (3) 25% corresponds to the upper limit of the appropriate range of particle size, which is equivalent to the second threshold value. (3) 20% corresponds to the above-mentioned third threshold value.

[0165] Moreover, in Fig.13A , 13B The treated liquid was fractionated 3 minutes after each of the time points T0, T2, T2', and T4 shown, and the fractionated liquid was used to perform a Buchner funnel test to measure the particle size. Furthermore, the treated liquid was dehydrated 15 minutes after each of the time points T0, T2, and T4 using a dehydrator, and the suspended matter concentration in the dehydrated filtrate and the water content of the dehydrated cake were measured.

[0166] The particle size was measured visually. Specifically, the particle size was measured by comparing a plurality of graphs showing particles having different particle sizes shown in a standard graph showing particle sizes with particles obtained by a Buchner funnel test.

[0167] The suspended matter concentration in the filtrate is measured in accordance with "14.2 Suspended matter" in JIS K 0102:2021.

[0168] The moisture content of the dehydrated cake is determined by the method described in Section 6 of Chapter 1 of Part 5 of the Water Test Method (2012 Edition).

[0169] like Fig.13A , Fig. 13B As shown in the figure, the light receiving amount variation index CI (3) Ability to control the dosing output of polymer aggregating agents.

[0170] Table 4 shows the particle size, the concentration of suspended matter in the filtrate, and the water content of the dehydrated cake. The particle size at T0, T2, T2', and T4 in Table 4 represents the particle size of the particles in the treatment liquid 3 minutes after each of the time points T0, T2, T2', and T4. In addition, the concentration of suspended matter in the filtrate and the water content of the dehydrated cake at T0, T2, T2', and T4 in Table 2 represent the results of measuring the specimen 15 minutes after each of the time points T0, T2, T2', and T4.

[0171] [Table 4]

[0172]

[0173] At time T0, time T2, and time T4, the light reception amount variation index CI (3) is below the second threshold value of 25%, as shown in Table 4, if the light reception amount variation index CI (3) If the particle size is below the second threshold, the particle size is below 1.00 mm, which can reduce the concentration of suspended matter contained in the dehydrated filtrate and also make the water content of the dehydrated cake low. (3) The desired particle size can be adjusted by controlling the amount of aggregating agent added. (3) , which can prevent the water content of the dehydrated cake from increasing and inhibit the leakage of particles into the filtrate.

[0174] Furthermore, by using the third threshold value (the light receiving amount variation index CI (3) PID control is disabled by setting the amount of the additive to 20% so that the amount of the additive does not become too small and the addition of the aggregating agent is continued at an addition rate that results in an appropriate particle size.

[0175] In the above-described embodiment, an embodiment has been described in which the second threshold value is set as the upper limit of the appropriate range of particle size, but it can be seen that when the first threshold value is set as the lower limit of the appropriate range of particle size, the particle size can be prevented from becoming too small, and the water content of the dehydrated cake can be prevented from increasing, and the leakage of particles into the filtrate can be suppressed.

[0176] Explanation of symbols

[0177] 3: Processing tank

[0178] 4: Dosing device

[0179] 8: Controller

[0180] 10: Aggregation status monitoring sensor

Claims

1. A method for determining an aggregation state, comprising irradiating a liquid containing particles with laser light, and determining the aggregation state of the particles based on the light reception intensity of scattered light resulting from the laser light being scattered by the particles, and The aggregation state of the particles is determined based on a variation index indicating variation in the received light intensity.

2. The focusing state determination method according to claim 1, wherein the variation index is a light receiving amount variation index CI expressed by formula (1): [Number 1] In the formula (1), S i : The integral value of the light receiving intensity in the i-th floc formation state measurement time domain S ave : an average value of the integrated value of the light reception intensity in the floc formation state measurement time domain when the light reception intensity is acquired n times in the floc formation state measurement time domain.

3. The aggregation state determination method according to claim 1 or 2, wherein the aggregation state is determined to be good when the variation index is above a first threshold value and below a second threshold value which is a value larger than the first threshold value. 4 . The aggregation state determination method according to claim 1 , wherein the aggregation state of the particles is determined based on a relationship between a particle size of the particles and a variation range of the light receiving intensity in addition to the variation index.

5. The aggregation state determination method according to claim 1 or 2, wherein the relationship between the variation index and the particle size is acquired in advance, and determination based on the variation index is performed within a particle size range determined based on the relationship.

6. 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 index indicating variation in light reception intensity of scattered light resulting from scattering of the laser light by the particles; and The aggregating agent adding step is to add the aggregating agent in an amount based on the aggregation state of the particles determined in the determining step.

7. The focusing processing method according to claim 6, wherein the variation index is a light receiving amount variation index value CI expressed by formula (2): [Number 2] In the formula (2), S i : The integral value of the light receiving intensity in the i-th floc formation state measurement time domain S ave : an average value of the integrated value of the light reception intensity in the floc formation state measurement time domain when the light reception intensity is acquired n times in the floc formation state measurement time domain.

8. The aggregation processing method according to claim 6 or 7, wherein when the change index is less than a first threshold, the amount of the aggregating agent added is increased, and when the change index exceeds a second threshold which is a value larger than the first threshold, the amount of the aggregating agent added is reduced.

9. The aggregation processing method according to claim 8, wherein after the variation index exceeds the second threshold, when a third threshold value that is a value larger than the first threshold value and smaller than the second threshold value is reached, the reduction of the amount of addition of the aggregating agent is stopped.

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