Sludge treatment system, control device, sludge treatment method, and program

Abstract

To easily add an optimum amount of flocculant.SOLUTION: A sludge treatment system includes: a water tank 100 into which sludge to be treated flows; an addition device 200 that adds a coagulant to the sludge stored in the water tank 100; a sensor 400 that acquires a state of aggregates in the sludge to which the coagulant has been added from the addition device 200; and a control device 500 that calculates an aggregation index indicating a state of the aggregate acquired by the sensor 400 and controls an addition amount of the coagulant added by the addition device 200 based on an amount of change in the aggregation index when the addition amount of the coagulant added by the addition device 200 is changed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sludge treatment system, a control device, a sludge treatment method, and a program.

Background Art

[0002] As one method of treating sludge, a method is exemplified in which a predetermined flocculant is added to the sludge stored in a water tank, and solid-liquid separation is performed using a dehydrator to remove moisture from the sludge to which the flocculant has been added, thereby obtaining dehydrated sludge and filtrate. When using such a method, it is necessary to control the addition amount of the flocculant added to the sludge. For example, a technique is considered in which aggregates in the sludge are imaged, and the addition amount of the flocculant is controlled based on the result of comparing the area of the imaged aggregates on the image with a preset reference area (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique as described in Patent Document 1, a reference area must be determined in advance. Further, since a preset reference is used to control the addition amount, it becomes difficult to easily calculate an addition amount suitable for the changed situation when the situation of the sludge changes. Therefore, there is a risk that a flocculant with an optimal addition amount cannot be added.

[0005] An object of the present invention is to provide a sludge treatment system, a control device, a sludge treatment method, and a program that can easily add a flocculant with an optimal addition amount.

Means for Solving the Problems

[0006] The sludge treatment system of the present invention comprises a water tank into which sludge to be treated flows in, an adding device for adding a flocculant to the sludge stored in the water tank, a sensor for acquiring the state of aggregates in the sludge to which the flocculant has been added from the adding device, a control device that calculates a flocculation index indicating the state of the aggregates acquired by the sensor, and controls the addition amount of the flocculant added by the adding device based on the change amount of the flocculation index when the addition amount of the flocculant added by the adding device is changed.

[0007] In addition, the control device of the present invention comprises an index calculation unit that calculates a flocculation index indicating the state of the aggregates acquired by a sensor that acquires the state of the aggregates in the sludge to which a flocculant has been added by an adding device in a water tank into which sludge to be treated flows in, and an addition amount control unit that controls the addition amount of the flocculant added by the adding device based on the change amount of the flocculation index when the addition amount of the flocculant added by the adding device is changed.

[0008] In addition, the sludge treatment method of the present invention comprises a process of calculating a flocculation index indicating the state of the aggregates acquired by a sensor that acquires the state of the aggregates in the sludge to which a flocculant has been added by an adding device in a water tank into which sludge to be treated flows in, and a process of controlling the addition amount of the flocculant added by the adding device based on the change amount of the flocculation index when the addition amount of the flocculant added by the adding device is changed.

[0009] In addition, the program of the present invention is a program for causing a computer to execute, comprising a procedure of calculating a flocculation index indicating the state of the aggregates acquired by a sensor that acquires the state of the aggregates in the sludge to which a flocculant has been added by an adding device in a water tank into which sludge to be treated flows in, Based on the change amount of the aggregation index when the addition amount of the flocculant added by the addition device is changed, execute the procedure for controlling the addition amount of the flocculant added by the addition device.

Advantages of the Invention

[0010] In the present invention, it is possible to easily add an optimal addition amount of the flocculant.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a diagram showing an embodiment of the sludge treatment system of the present invention. As shown in FIG. 1, the sludge treatment system in this embodiment includes a water tank 100, an addition device 200, a flocculant storage tank 210, a densitometer 300, a sensor 400, and a control device 500.

[0014] The water tank 100 is a storage tank into which the sludge to be treated flows and stores the inflowing sludge to be treated. The sludge to be treated contains a sludge-like substance formed by the aggregation of the final products of organic and inorganic substances generated in the treatment process of a sewage treatment plant or the waste liquid treatment process of a factory. Also, since the sludge to be treated is waste, it cannot be used as it is. Therefore, for the sludge to be treated, for example, coagulation treatment by adding a coagulant or dehydration treatment such as pressing or centrifugation using a dehydrator is performed to remove the dehydrated sludge from the sludge to be treated and obtain a reusable liquid. The dehydrated sludge preferably has a lower water content and is treated as waste or reused as fertilizer or the like. The water tank 100 has a predetermined capacity. The adding device 200 adds the coagulant stored in the coagulant storage tank 210 to the sludge stored in the water tank 100. The adding device 200 adds the coagulant in an amount based on an instruction from the control device 500 from the coagulant storage tank 210 to the sludge stored in the water tank 100. The densitometer 300 measures the sludge concentration of the sludge to be treated flowing into the water tank. The densitometer 300 is not particularly limited as long as it can measure the sludge concentration of the sludge to be treated, but is preferably an SS (Suspended Solids) meter. The densitometer 300 outputs the measured value to the control device 500. The sensor 400 acquires the state of the aggregates (flocs) in the sludge to which the coagulant has been added from the adding device 200 in the sludge stored in the water tank 100. The sensor 400 may be, for example, a non-contact image sensor (camera) that captures an image of the sludge. The sensor 400 is preferably an infrared sensor. The sensor 400 may be a camera (for example, a video camera that continuously captures images) that captures an image of the sludge in the water tank 100 at a time interval equal to or less than a preset time interval. The sensor 400 outputs the image data indicating the acquired (captured) image to the control device 500. The control device 500 controls the amount of coagulant added by the adding device 200 from the coagulant storage tank 210 based on the concentration value output from the densitometer 300 and the state of the aggregates acquired (captured) by the sensor 400. Note that a stirring member for stirring the treated sludge may be provided in the water tank 100.

[0015] FIG. 2 is a diagram showing an example of the internal configuration of the control device 500 shown in FIG. 1. As shown in FIG. 2, the control device 500 shown in FIG. 1 includes an index calculation unit 510 and an addition amount control unit 520. Note that FIG. 2 shows only the main components related to this embodiment among the components included in the control device 500 shown in FIG. 1.

[0016] The index calculation unit 510 calculates an aggregation index indicating the state of the aggregates acquired by the sensor 400. When the sensor 400 is an image sensor, the index calculation unit 510 calculates, as the aggregation index, the feature amount of the aggregates in the sludge in the water tank 100 from the image captured by the image sensor. Here, the index calculation unit 510 calculates, as the feature amount, the number, particle diameter, or displacement amount of the suspended substances contained in the sludge in the water tank 100 from the image captured by the image sensor. For example, the index calculation unit 510 may color the portions with differences between frames white using an image processing technique such as Motion History Image for the image (video) captured by the image sensor, and calculate the count number (displacement amount) of the colored white dots as the feature amount. Further, the index calculation unit 510 may visualize the flow of the flocs in the sludge in the water tank 100 using an image processing technique such as Optical flow, measure the width of the flow, and calculate the particle diameter as the feature amount. Alternatively, when the sensor 400 is an image sensor, the index calculation unit 510 may calculate, as the aggregation index, the number of edges of the aggregates in the sludge in the water tank 100 from the image captured by the image sensor. Here, the index calculation unit 510 may detect, as the edges of the aggregates, the pixels whose color difference (for example, the difference in RGB values) between adjacent pixels in the image captured by the image sensor is equal to or greater than the threshold value, and calculate the number (number of pixels) of the detected edges as the aggregation index. Alternatively, when the sensor 400 is an image sensor, the index calculation unit 510 may calculate, as the aggregation index, the area of the aggregates in the sludge in the water tank 100 from the image captured by the image sensor. Alternatively, when the sensor 400 is an image sensor, the index calculation unit 510 may calculate, as the aggregation index, the number of the aggregates in the sludge in the water tank 100 from the image captured by the image sensor. Further, when the sensor 400 is an image sensor, the index calculation unit 510 may calculate, as the aggregation index, any combination of the number of edges, area, and number of the aggregates in the sludge in the water tank 100 from the image captured by the image sensor.

[0017] The addition amount control unit 520 controls the addition amount of the flocculant added by the addition device 200 based on the change amount of the flocculation index calculated by the index calculation unit 510 when the addition amount of the flocculant added by the addition device 200 is changed. Specifically, the addition amount control unit 520 controls the addition amount of the flocculant added by the addition device 200 based on the change amount of the flocculation index when the addition amount of the flocculant added by the addition device 200 is changed and the change amount of the addition amount of the flocculant added by the addition device 200. More specifically, the addition amount control unit 520 calculates the flocculation change amount, which is the ratio of the change amount of the flocculation index to the change amount of the addition amount of the flocculant added by the addition device 200, and compares it with a preset threshold value (the 1 first threshold value). Then, the addition amount control unit 520 controls the addition amount of the flocculant added by the addition device 200 based on the result of the comparison. The flocculation change amount V n is calculated by the following (Equation 1).

[0018] [Number]

[0019] In (Equation 1), C n is the flocculation index. C n-1 is the flocculation index before the change in the addition amount of the flocculant. Also, P n is the addition amount of the flocculant. P n-1 is the addition amount of the flocculant before the change in the addition amount of the flocculant.

[0020] When the flocculation change amount V n is less than or equal to the preset threshold value, the addition amount control unit 520 controls to reduce the addition amount of the flocculant added by the addition device 200. On the other hand, when the flocculation change amount V n exceeds the preset threshold value, the addition amount control unit 520 controls to increase the addition amount of the flocculant added by the addition device 200.

[0021] Further, the addition amount control unit 520 controls the addition amount of the flocculant added by the addition device 200 based on the change amount per unit time of the sludge concentration, which is the value output from the densitometer 300, and the change amount of the calculated flocculation index. Specifically, the addition amount control unit 520 calculates the concentration change amount, which is the change amount per unit time of the sludge concentration, which is the value output from the densitometer 300. When the concentration change amount exceeds a preset threshold value (the 2 first threshold value), if the concentration is changing in the direction of increasing, the addition amount control unit 520 performs control to increase the addition amount of the flocculant added by the addition device 200. On the other hand, when the concentration change amount exceeds a preset threshold value, if the concentration is changing in the direction of decreasing, the addition amount control unit 520 performs control to reduce the addition amount of the flocculant added by the addition device 200. Further, when the concentration change amount is equal to or less than a preset threshold value, the addition amount control unit 520 performs control of the addition amount based on the above-described flocculation index.

[0022] Hereinafter, the sludge treatment method in the sludge treatment system shown in FIG. 1 will be described. FIGS. 3A and 3B are flowcharts for explaining an example of a method for controlling the addition amount based on the flocculation index among the sludge treatment methods in the sludge treatment system shown in FIG. 1.

[0023] First, the addition device 200 adds a flocculant from the flocculant storage tank 210 to the water tank 100 in an addition amount P n-1 . After a preset time has elapsed (step S2), the index calculation unit 510 of the control device 500 calculates the flocculation index C n-1 from the state of the flocs in the sludge in the water tank 100 acquired by the sensor 400 (step S3). Thereafter, the addition device 200 adds a flocculant from the flocculant storage tank 210 to the water tank 100 in an addition amount P n . After a preset time has elapsed (step S5), the index calculation unit 510 of the control device 500 calculates the flocculation index C n from the state of the flocs in the sludge in the water tank 100 measured by the sensor 400 (step S6). Then, the index calculation unit 510 of the control device 500 uses (Equation 1) to calculate the flocculation change amount Vn Calculate it (step S7). Note that the amount of flocculation change V n may be calculated by the addition amount control unit 520 instead of the index calculation unit 510.

[0024] The addition amount control unit 520 of the control device 500 determines whether the calculated amount of flocculation change V n exceeds a preset threshold value (step S8). If the amount of flocculation change V n is a value exceeding the preset threshold value, the addition amount control unit 520 increases the amount of the flocculant added from the addition device 200 (step S9). The addition amount control unit 520 controls the addition device 200 to add the flocculant with the increased addition amount P n+1 from the flocculant storage tank 210 (step S10). On the other hand, in step S8, if the amount of flocculation change V n is equal to or less than the preset threshold value, the addition amount control unit 520 reduces the amount of the flocculant added from the addition device 200 (step S11). The addition amount control unit 520 controls the addition device 200 to add the flocculant with the reduced addition amount P n+1 from the flocculant storage tank 210 (step S12). Then, the process of step S5 is performed. Note that the amount of increase and decrease of the flocculant may be a preset amount or an amount calculated according to the amount of flocculation change.

[0025] FIG. 4 is a flowchart for explaining an example of a control method for the addition amount based on the sludge concentration in the sludge treatment method in the sludge treatment system shown in FIG. 1.

[0026] The addition amount control unit 520 calculates the concentration change amount, which is the change amount per unit time of the sludge concentration and is the value output from the concentration meter 300 (step S21). The addition amount control unit 520 determines whether the calculated concentration change amount exceeds a preset threshold value (step S22). When the concentration change amount exceeds the preset threshold value, the addition amount control unit 520 determines whether the sludge concentration is changing in the direction of increasing (step S23). When the sludge concentration is changing in the direction of increasing, the addition amount control unit 520 increases the addition amount of the flocculant added by the addition device 200 from the flocculant storage tank 210 (step S24). Then, the addition amount control unit 520 controls the addition device 200 to add the increased addition amount of the flocculant from the flocculant storage tank 210 (step S25). The amount by which the addition amount is increased may be a preset amount or an amount calculated according to the change amount of the sludge concentration.

[0027] On the other hand, in step S23, when the sludge concentration is changing in the direction of decreasing, the addition amount control unit 520 reduces the addition amount of the flocculant added by the addition device 200 from the flocculant storage tank 210 (step S26). Then, the addition amount control unit 520 controls the addition device 200 to add the reduced addition amount of the flocculant from the flocculant storage tank 210 (step S27). The amount by which the addition amount is reduced may be a preset amount or an amount calculated according to the change amount of the sludge concentration.

[0028] Also, in step S22, when the concentration change amount is less than or equal to the preset threshold value, the addition amount control unit 520 performs control of the addition amount based on the flocculation index described using the flowcharts shown in FIGS. 3A and 3B (step S28).

[0029] Note that even while the control of the addition amount based on the flocculation index described using the flowcharts shown in FIGS. 3A and 3B is being performed, the processes of steps S21 and S22 are being carried out. When the concentration change amount exceeds the threshold value, the processes of steps S23 to S27 are performed with priority over the control of the addition amount based on the flocculation index described using the flowcharts shown in FIGS. 3A and 3B.

[0030] Thus, in this embodiment, the control device 500 controls the addition amount of the flocculant to be added based on the change amount of the flocculation index before and after changing the addition amount of the flocculant added to the sludge in the water tank 100. Therefore, it is not necessary to perform operations such as data collection for providing a reference value or a reference range of the addition amount, and it is possible to quickly respond to changes in sludge properties. Also, if the aggregates in the existing mixing tank are imaged, the addition amount can be controlled, and no additional cost or space is required. That is, it is possible to easily control the addition amount of the flocculant suitable for the change in the state of the aggregates when the flocculant is added. Further, the control device 500 controls the addition amount of the flocculant based on the sludge concentration and the flocculation index according to the change amount of the sludge concentration. Thereby, when the sludge concentration changes rapidly, it is possible to quickly respond to the change. Note that, as control based on the sludge concentration, a method of changing the flocculant addition amount to a specified value according to the sludge concentration may be applied. When the change amount of the sludge concentration exceeds the specified value, it is preferable to change the flocculant addition amount by only the specified value. Thereby, when the sludge concentration changes, instead of resetting the flocculant addition amount, the addition amount is changed based on the previous flocculant addition amount, so that it is possible to respond more appropriately and quickly to the change in the sludge concentration. (Application Example)

[0031] FIG. 5 is a diagram showing an application example of the sludge treatment system of the present invention. As shown in FIG. 5, this application example includes a reaction tank 110, addition devices 201 and 202, a cationic polymer flocculant storage tank 211, an anionic polymer flocculant storage tank 212, a densitometer 300, a sensor 400, a control device 500, and a dehydrator 600. Each of the densitometer 300, the sensor 400, and the control device 500 is the same as that in the embodiment shown in FIG. 1.

[0032] The reaction tank 110 corresponds to the water tank 100 in the form shown in FIG. 1. The reaction tank 110 stores the sludge to be treated. The addition device 201 adds a flocculant from the cationic polymer flocculant storage tank 211 to the sludge stored in the reaction tank 110 based on an instruction from the control device 500. The addition device 202 adds a flocculant from the anionic polymer flocculant storage tank 212 to the sludge stored in the reaction tank 110 based on an instruction from the control device 500. The dehydrator 600 dehydrates the sludge treated in the reaction tank 110 and separates it into filtrate and dehydrated sludge for discharge. Note that the reaction tank 110 and the dehydrator 600 may be integrated. There are many types of dehydrators 600, such as screw press type and multi-disc type, but it is not particularly limited.

[0033] The results when the present invention was implemented are described below. (Example 1)

[0034] ·Test method In the sludge treatment device, simulated sludge, a cationic polymer flocculant, and an anionic polymer flocculant were supplied to the reaction tank, and based on the change amount of the number of edges of the aggregates acquired by the image sensor installed in the reaction tank, a cationic polymer flocculant and an anionic polymer flocculant with automatically controlled addition amounts were added to measure the concentration of the cationic polymer flocculant and the moisture content of the dehydrated sludge. The ratio of the addition concentrations of the cationic polymer flocculant and the anionic polymer flocculant was kept constant at 5 to 1. ·Test conditions Simulated sludge (sludge concentration 1%): Dried okara (Kobe Food Industry) 8.2 g / L, pure koji miso (Marusan Eye Co., Ltd.) 24.1 g / L Sludge treatment device: Valute dehydrator ES-051 (Amcon Co., Ltd.) Sludge supply rate: 5.5 L / min Cationic polymer flocculant: Orfloc OX-307 (Organo Co., Ltd.) Anionic polymer flocculant: Orfloc OA-12H (Organo Co., Ltd.) Moisture content measuring device for dehydrated sludge: Heating drying type moisture meter MX-50 (A&D Co., Ltd.) ·Test results The test results are shown in Table 1. As shown in Table 1, the concentration of the cationic polymer flocculant changed according to the change in the sludge concentration, and the water content also stabilized at around 80%. That is, by using automatic control based on the change amount of the flocculation index with the number of edges of the floc as the flocculation index, the addition amount of the flocculant could be increased or decreased according to the change in the sludge concentration.

Table 1

[0035] ·Test method In the sludge treatment device, simulated sludge, a cationic polymer flocculant, and an anionic polymer flocculant were supplied to the reaction tank, and based on the change amount of the area of the flocs acquired by the image sensor installed in the reaction tank, a cationic polymer flocculant and an anionic polymer flocculant with automatically controlled addition amounts were added to measure the concentration of the cationic polymer flocculant and the water content of the dewatered sludge. The ratio of the addition concentrations of the cationic polymer flocculant and the anionic polymer flocculant was kept constant at 5 to 1. ·Test conditions The same as in Example 1. ·Test results The test results are shown in Table 2. As shown in Table 2, the concentration of the cationic polymer flocculant changed according to the change in the sludge concentration, and the water content also stabilized at around 80%. That is, by using automatic control based on the change amount of the flocculation index with the area of the flocs as the flocculation index, the addition amount of the flocculant could be increased or decreased according to the change in the sludge concentration.

Table 2

[0036] ·Test method In a sludge treatment apparatus, sludge, a cationic polymer flocculant, and an anionic polymer flocculant were supplied to a reaction tank. Based on the change amount of the number of edges of the aggregates obtained by an image sensor installed in the reaction tank, a cationic polymer flocculant with an automatically controlled addition amount and an anionic polymer flocculant with a specified addition amount were added to measure the concentration of the cationic polymer flocculant and the moisture content of the dewatered sludge. In Comparative Example 1, a cationic polymer flocculant with an addition amount determined to be appropriately treatable was added based on sludge concentration, floc appearance, moisture content, etc. The addition amount of the anionic polymer flocculant with respect to the sludge concentration was the same in the Examples and the Comparative Example. · Test conditions Sludge: Biological treatment excess sludge Sludge treatment apparatus: Helios dehydrator SK-1000UP (Helios Co., Ltd.) Sludge supply amount: 6.0 - 8.0 m 3 / h Cationic polymer flocculant: Orfloc EC-559K (Organo Corporation) Anionic polymer flocculant: Orfloc M-4414 (Organo Corporation) Dewatered sludge moisture content measuring instrument: Heating drying type moisture meter MX-50 (A&D Company, Ltd.) · Test results The test results are shown in Table 3. As shown in Table 3, the concentration of the cationic polymer flocculant changed at 440 ppm in Comparative Example 1, while it changed between 390 - 460 ppm in Example 3. By using automatic control based on the change amount of the number of edges of the aggregates, the usage amount of the cationic polymer flocculant could be reduced by about 9%. When comparing the moisture content, Example 3 increased by a maximum of 3% compared to Comparative Example 1, suggesting that in the automatic control operation based on the change amount of the number of edges of the aggregates, it may not be possible to fully respond to fluctuations in sludge concentration.

Table 3

[0037] · Test method In a sludge treatment apparatus, sludge, a cationic polymer flocculant, and an anionic polymer flocculant were supplied to a reaction tank. Based on the change amount of the number of edges of the aggregates obtained by an image sensor installed in the reaction tank and the change amount of the sludge concentration, a cationic polymer flocculant with an automatically controlled addition amount and an anionic polymer flocculant with a specified addition amount were added to measure the concentration of the cationic polymer flocculant and the water content of the dewatered sludge. In Comparative Example 2, a cationic polymer flocculant with an addition amount determined to be appropriately treatable based on the sludge concentration, the appearance of the flocs, the water content, etc. was added. The addition amount of the anionic polymer flocculant with respect to the sludge concentration was the same in the Example and the Comparative Example. ·Test conditions Same as Example 3. ·Test results The test results are shown in Table 4. As shown in Table 4, in Comparative Example 2, the cationic polymer flocculant concentration changed from 550 to 570 ppm, whereas in Example 4, it changed from 460 to 540 ppm. By using an automatic control operation based on the change amount of the number of edges of the aggregates and the change amount of the sludge concentration, the usage amount of the cationic polymer flocculant could be reduced by approximately 11%. Regarding the water content, Example 4 and Comparative Example 2 were equivalent to each other. Thus, by using an automatic control operation based on the change amount of the number of edges of the aggregates and the change amount of the sludge concentration, it is possible to cope with fluctuations in the sludge concentration and reduce the usage amount of the cationic polymer flocculant.

Table 4

[0038] As described above, each component has been described with each function (process) being shared, but this assignment is not limited to the above-described one. Also, regarding the configuration of the components, the above-described form is merely an example and is not limited thereto.

[0039] The processes performed by the above-described control device 500 may be performed by logic circuits respectively fabricated according to the purpose. Alternatively, a computer program (hereinafter referred to as a program) that describes the processing content as procedures may be recorded on a recording medium readable by the control device 500, and the program recorded on this recording medium may be read by the control device 500 and executed. The recording medium readable by the control device 500 refers to removable recording media such as a floppy (registered trademark) disk, a magneto-optical disk, a DVD (Digital Versatile Disc), a CD (Compact Disc), a Blu-ray (registered trademark) Disc, a USB (Universal Serial Bus) memory, etc., and also refers to memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory) built in the control device 500, and an HDD (Hard Disc Drive), etc. The program recorded on this recording medium is read by a CPU provided in the control device 500, and under the control of the CPU, the same processes as those described above are performed. Here, the CPU operates as a computer that executes the program read from the recording medium on which the program is recorded.

Explanation of Signs

[0040] 100 Water tank 110 Reaction tank 200~202 Adding device 210 Coagulant storage tank 211 Cationic polymer coagulant storage tank 212 Anionic polymer coagulant storage tank 300 Concentration meter 400 Sensor 500 Control device 510 Index calculation unit 520 Addition amount control unit 600 Dehydrator

Claims

1. A water tank into which the sludge to be treated flows, An adding device for adding a flocculant to the sludge stored in the water tank, A sensor for acquiring the state of flocs in the sludge to which the flocculant has been added from the adding device, A control device that calculates a flocculation index indicating the number, particle size, displacement amount, number of edges, or area of the flocs acquired by the sensor, and controls the addition amount of the flocculant added by the adding device based on the change amount of the flocculation index when the addition amount of the flocculant added by the adding device is changed. The control device compares a flocculation change amount, which is the ratio of the change amount of the flocculation index to the change amount of the addition amount when the addition amount of the flocculant is changed, with a predetermined first threshold value. When the flocculation change amount exceeds the first threshold value, the control device increases the addition amount of the flocculant added by the adding device. When the flocculation change amount is less than or equal to the first threshold value, the control device decreases the addition amount of the flocculant added by the adding device. A sludge treatment system.

2. In the sludge treatment system according to Claim 1, It has a densitometer for measuring the sludge concentration of the sludge to be treated flowing into the water tank, The control device controls the addition amount of the flocculant added by the adding device based on the change amount per unit time of the sludge concentration measured by the densitometer and the change amount of the flocculation index. A sludge treatment system.

3. In the sludge treatment system according to Claim 2, When the change amount per unit time of the sludge concentration measured by the densitometer exceeds a predetermined second threshold value, the control device controls the addition amount of the flocculant added by the adding device based on the change in the sludge concentration measured by the densitometer. A sludge treatment system.

4. In the sludge treatment system according to any one of Claims 1 to 3, The sensor is an image sensor that captures an image of the sludge, The control device is a sludge treatment system that calculates, as the aggregation index, the feature amount of the aggregates in the sludge from the image captured by the image sensor.

5. An index calculation unit that calculates an aggregation index indicating the number, particle diameter, displacement amount, number of edges, or area of the aggregates obtained by a sensor that acquires the state of the aggregates in the sludge to which a flocculant is added by an adding device in a water tank into which the sludge to be treated flows; An addition amount control unit that controls the addition amount of the flocculant added by the adding device based on the change amount of the aggregation index when the addition amount of the flocculant added by the adding device is changed, The addition amount control unit compares the aggregation change amount, which is the ratio of the change amount of the aggregation index to the change amount of the addition amount when the addition amount of the flocculant is changed, with a predetermined first threshold value. When the aggregation change amount exceeds the first threshold value, the addition amount of the flocculant added by the adding device is increased. When the aggregation change amount is less than or equal to the first threshold value, the addition amount of the flocculant added by the adding device is decreased. A control device.

6. In the control device according to claim 5, The addition amount control unit controls the addition amount of the flocculant added by the adding device based on the change amount per unit time of the sludge concentration of the sludge to be treated flowing into the water tank and the change amount of the aggregation index. A control device.

7. In the control device according to claim 6, When the change amount per unit time of the sludge concentration exceeds a predetermined second threshold value, the addition amount control unit controls the addition amount of the flocculant added by the adding device based on the change in the sludge concentration. A control device.

8. In the control device according to any one of claims 5 to 7, The index calculation unit is an image sensor that captures an image of the sludge, and calculates, as the aggregation index, the feature amount of the aggregates in the sludge from the image captured by the image sensor. A control device.

9. A process of calculating an aggregation index indicating the number, particle size, displacement amount, number of edges, or area of aggregates in sludge obtained by a sensor that acquires the state of aggregates in sludge to which a flocculant is added by an adding device in a water tank into which sludge to be treated flows, A process of controlling the addition amount of the flocculant added by the adding device based on the change amount of the aggregation index when the addition amount of the flocculant added by the adding device is changed, A process of comparing an aggregation change amount, which is the ratio of the change amount of the aggregation index to the change amount of the addition amount when the addition amount of the flocculant is changed, with a predetermined first threshold value, When the aggregation change amount exceeds the first threshold value, a process of increasing the addition amount of the flocculant added by the adding device, A sludge treatment method that performs a process of decreasing the addition amount of the flocculant added by the adding device when the aggregation change amount is less than or equal to the first threshold value.

10. On a computer, A procedure for calculating an aggregation index indicating the number, particle size, displacement amount, number of edges, or area of aggregates in sludge obtained by a sensor that acquires the state of aggregates in sludge to which a flocculant is added by an adding device in a water tank into which sludge to be treated flows, A procedure for controlling the addition amount of the flocculant added by the adding device based on the change amount of the aggregation index when the addition amount of the flocculant added by the adding device is changed, A procedure for comparing an aggregation change amount, which is the ratio of the change amount of the aggregation index to the change amount of the addition amount when the addition amount of the flocculant is changed, with a predetermined first threshold value, When the aggregation change amount exceeds the first threshold value, a procedure for increasing the addition amount of the flocculant added by the adding device, A program for causing the computer to execute a procedure for decreasing the addition amount of the flocculant added by the adding device when the aggregation change amount is less than or equal to the first threshold value.

Images