Information processing apparatus, water treatment system, and chemical-feeding rate determination method

Abstract

To grasp the excess and deficiency of a chemical feed rate from a floc image to properly adjust the chemical feed rate.SOLUTION: An information processing device (1) includes a sludge image acquisition unit (101) configured to acquire a sludge image of flocculated sludge in which a plurality of flocs overlap, the sludge image being captured by an imaging device, a luminance histogram creation unit (102) configured to create a luminance histogram for the sludge image, and a determination unit (103) configured to determine excess or deficiency of a chemical injection rate with respect to the flocculated sludge by using the luminance histogram.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an information processing device, a water treatment system, a chemical injection rate determination method, and a chemical injection rate determination program. [Background technology]

[0002] A conventional technique involves adding a chemical such as a flocculant to a liquid to be treated, such as sewage sludge, and stirring the mixture to aggregate suspended solids to form flocs, and then subjecting the aggregate of flocs, or flocculated sludge, to solid-liquid separation to obtain dewatered suspended solids. In a plant that performs the above-described treatment, in order to stably perform solid-liquid separation, it is necessary to properly grasp the state of floc formation from photographed images of the flocs and to appropriately adjust the amount of chemical agent added (chemical dosing rate) in response to changes in the state of formation. Techniques for this purpose include those described, for example, in Patent Documents 1 to 3 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-081640 A [Patent Document 2] Patent No. 7339105 [Patent Document 3] JP 2023-173197 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the course of developing a technology for grasping the state of flocs from images of the flocs, the inventors discovered that if it were possible to determine the chemical feeding rate not only by grasping the state of floc formation from images of the flocs but also by calculating backward whether the chemical feeding rate was excessive or insufficient from images of floc formation, then it would be possible to adjust the chemical feeding rate more appropriately.

[0005] An object of one aspect of the present invention is to grasp whether a chemical injection rate is excessive or insufficient from a floc image and to adjust the chemical injection rate appropriately. [Means for solving the problem]

[0006] In order to solve the above problems, an information processing device according to one embodiment of the present invention includes a sludge image acquisition unit that acquires sludge images captured by an imaging device of flocculated sludge, which is formed by aggregating solid floating matter in sludge and consisting of multiple overlapping flocs; a brightness histogram creation unit that creates a brightness histogram for the sludge image, which shows the number of pixels in the same brightness range for each brightness range; and a determination unit that uses the brightness histogram to determine whether the chemical dosing rate for the flocculated sludge is excessive or insufficient.

[0007] Furthermore, a chemical dosing rate determination method according to one embodiment of the present invention is a chemical dosing rate determination method executed by one or more information processing devices, and includes a sludge image acquisition step of acquiring an image of flocculated sludge, which is formed by aggregating solid floating matter in the sludge and consisting of multiple overlapping flocs, as a sludge image; a brightness histogram creation step of creating a brightness histogram for the sludge image, which shows the number of pixels in the same brightness range for each brightness range; and a determination step of using the brightness histogram to determine whether the chemical dosing rate for the flocculated sludge is excessive or insufficient. [Effects of the Invention]

[0008] According to one aspect of the present invention, whether the chemical injection rate is excessive or insufficient can be determined from a floc image, and the chemical injection rate can be appropriately adjusted. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of the configuration of a water treatment system according to an embodiment of the present invention. [Figure 2] 2 is a block diagram showing an example of the configuration of an information processing device included in the water treatment system shown in FIG. 1. FIG. [Figure 3] 3 is a flowchart showing an example of processing performed by the information processing device shown in FIG. 2. [Figure 4]3 is a diagram showing an example of a sludge image acquired by a sludge image acquisition unit included in the information processing device shown in FIG. 2. FIG. [Figure 5] 3 is a diagram showing an example of a luminance histogram created by a luminance histogram creating unit included in the information processing device shown in FIG. 2. FIG. [Figure 6] 6 is a diagram showing the number of pixels with a luminance value less than 66 in an example of a luminance histogram similar to the luminance histogram shown in FIG. 5. FIG. [Figure 7] FIG. 6 is a diagram showing the numbers of pixels included in a first luminance range and a second luminance range in an example of a luminance histogram similar to the luminance histogram shown in FIG. 5. [Figure 8] FIG. 4 is a diagram showing an example of a sludge image and the number of pixels included in a first brightness range and a second brightness range. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Configuration of water treatment system 100> 1 is a diagram showing an example of the configuration of a water treatment system 100 according to an embodiment of the present invention. The water treatment system 100 is a system used in a plant that adds a chemical agent that coagulates suspended solids to the liquid to be treated in a coagulation tank 51 to form flocs, and then performs solid-liquid separation of the flocculated sludge. In the following, an example will be described in which the liquid to be treated is sludge produced in the biological treatment of sewage or the like.

[0011] Sludge is a liquid containing fine solids generated during wastewater treatment and the like, and is also called slurry. The sludge may be, for example, primary sludge or final sludge (excess sludge) generated in a sewage treatment plant, or a mixed raw sludge that combines both. Furthermore, flocculated sludge is formed by flocculating suspended solids in sludge, resulting in overlapping flocs. As shown in FIG. 2, the water treatment system 100 includes an information processing device 1, a control device 2, an addition device 3, an illumination device 41, a photographing device 42, a flocculator 5, a presentation device 6, and a dehydrator 7.

[0012] <Configuration of information processing device 1> Fig. 2 is a block diagram showing an example of the configuration of the information processing device 1 included in the water treatment system 100 shown in Fig. 1. The information processing device 1 determines whether the chemical feeding rate is excessive or insufficient from a sludge image of the flocculated sludge captured by the imaging device 42. As shown in Fig. 2, the information processing device 1 includes a control unit 10, a communication unit 11, an input unit 12, and a memory unit 13.

[0013] The control unit 10 controls each unit of the information processing device 1 in an integrated manner. The control unit 10 includes a sludge image acquisition unit 101, a brightness histogram creation unit 102, and a determination unit 103. Details of each unit included in the control unit 10 will be described later. The communication unit 11 is a communication interface that enables the information processing device 1 to communicate with other devices. The input unit 12 accepts input of various data to the information processing device 1. The memory unit 13 stores various data used by the information processing device 1.

[0014] <Configuration of the control device 2 and the addition device 3> The control device 2 controls the addition device 3, the lighting device 41, the photographing device 42, the motor 53, the presentation device 6, and the dehydrator 7. The control device 2 is, for example, a PLC (Programmable Logic Controller).

[0015] The control device 2 determines the state of floc formation by evaluating the color tone of the flocculated sludge and the size of the flocs based on the sludge image captured by the imaging device 42. At this time, in the information processing device 1, a communication processing unit (not shown) included in the control unit 10 reads the sludge image from the memory unit 13 and transmits the sludge image to the control device 2 via the communication unit 11. The control device 2 automatically performs appropriate operation of the flocculator 5 by controlling the rotation speed of the motor 53 based on the determined state of floc formation.

[0016] The control device 2 controls the chemical feeding rate for the flocculated sludge by controlling the operation of the addition device 3. The chemical feeding rate is expressed by the following formula (1). In the following formula (1), CFD is the chemical feeding rate [%], AD is the dissolved concentration [%] of the chemical supplied to the flocculation tank 51, and AF is the amount [m 3 ]. MD is the concentration [%] of suspended solids in the sludge supplied to the coagulation tank 51, and MF is the amount [m 3 ].

[0017] CFD=(AD×AF×100) / (MD×MF)...(1)

[0018] The adding device 3 adds a chemical agent for flocculating suspended solids to the sludge in the coagulation tank 51 through the chemical agent addition port 56 based on instructions from the control device 2. The chemical agent includes at least a flocculant. The adding device 3 has a chemical agent injection pump for adding the chemical agent.

[0019] <Configuration of the lighting device 41 and the imaging device 42> An illumination device 41 and a photographing device 42 are attached to an inspection window 54 provided in the coagulation tank 51. The illumination device 41 irradiates light onto the coagulated sludge in the coagulation tank 51 through the inspection window 54. The photographing device 42 photographs the coagulated sludge in the coagulation tank 51 through the inspection window 54. The photographing device 42 may be capable of at least taking still images. It is preferable that the coagulation tank 51 is opaque so that the way light hits the flocs does not change during operation of the water treatment system 100. Furthermore, it is preferable that the illumination device 41 and the photographing device 42 are housed in a light-blocking dark box that is open on the inspection window 54 side.

[0020] <Configuration of Flocculator 5> The flocculator 5 is a device that forms flocs by agitating sludge in a coagulation tank 51. Specifically, the flocculator 5 coagulates suspended solids in the sludge to form flocs, thereby producing coagulated sludge. The flocculator 5 includes a coagulation tank 51, an agitator blade 52, a motor 53, and an inspection window 54. The flocculator 5 also has a sludge inlet 55, a chemical addition inlet 56, and a discharge outlet 57.

[0021] The sludge to be treated is continuously or intermittently supplied into the coagulation tank 51 from a sludge inlet 55 by a supply device (not shown) provided in the water treatment system 100. The supply rate of the sludge may be automatically controlled by the supply device or the control device 2 according to the treatment rate of the sludge by the flocculator 5 and the dehydrator 7.

[0022] With the chemicals added to the sludge, the motor 53 rotates the agitator blade 52 to agitate the sludge and chemicals, forming flocs. The flocculated sludge, which is a mixture of the formed flocs and the water contained in the sludge, is discharged from the discharge port 57.

[0023] <Configuration of presentation device 6> The presentation device 6 presents an increase or decrease in the drug injection rate in accordance with the determination result of the determination unit 103 regarding whether the drug injection rate is excessive or insufficient, based on an instruction from the control device 2. The presentation device 6 is, for example, a display device that displays an increase or decrease in the drug injection rate. The determination regarding whether the drug injection rate is excessive or insufficient by the determination unit 103 will be described in detail later.

[0024] <Configuration of dehydrator 7> The dehydrator 7 is a device that separates solids and liquids from the flocculated sludge in which flocs have formed. Specifically, the dehydrator 7 is disposed downstream of the flocculator 5, and dehydrates the flocculated sludge discharged from the flocculator 5 to separate it into solids and liquids. The dehydrator 7 is a screw press type dehydrator that includes an outer screen 71 and a screw 72.

[0025] The dehydrator 7 is formed with a sludge inlet 73, a filtrate outlet 74, and a dehydrated cake outlet 75. The dehydrator 7 also includes a motor (not shown) for rotating the screw 72. The dehydrator 7 is not limited to a screw press type dehydrator as long as it can dehydrate the flocculated sludge. For example, the dehydrator 7 may be a centrifugal dehydrator, a filter press type dehydrator, a belt press dehydrator, or the like.

[0026] The flocculated sludge is supplied into the outer screen 71 from a sludge inlet 73 of the dehydrator 7. In the dehydrator 7, the flocculated sludge is dehydrated under pressure by a screw 72, and the filtrate is discharged from a filtrate outlet 74. After the flocculated sludge is dehydrated, the dehydrated cake is discharged from a dehydrated cake outlet 75.

[0027] <Processing of information processing device 1> Fig. 3 is a flowchart showing an example of processing by the information processing device 1 shown in Fig. 2. The following describes the processing by the information processing device 1, but also serves as a description of a drug injection rate determination method. The drug injection rate determination method includes the steps shown in Fig. 3. Each step shown in Fig. 3 is executed by one or more information processing devices.

[0028] As shown in FIG. 3, in the control unit 10, the sludge image acquisition unit 101 acquires a sludge image of the flocculated sludge taken by the photographing device 42 (S1: sludge image acquisition step). At this time, the sludge image acquisition unit 101 acquires an image of the flocculated sludge as a sludge image from the photographing device 42 via the communication unit 11. Note that the sludge image acquisition unit 101 may acquire the sludge image by inputting a sludge image accepted by the input unit 12. The sludge image acquisition unit 101 stores the acquired sludge image in the memory unit 13. For example, the sludge image acquisition unit 101 acquires the sludge image shown in FIG. 4.

[0029] <Sludge image> Fig. 4 is a diagram showing an example of a sludge image acquired by the sludge image acquisition unit 101 included in the information processing device 1 shown in Fig. 2. Reference numeral 401 in Fig. 4 indicates a sludge image when the flocs are in good condition, and reference numeral 402 in Fig. 4 indicates a sludge image when the flocs are small in size. Reference numeral 403 in Fig. 4 indicates a sludge image when the chemical feeding rate relative to the flocculated sludge is insufficient, and reference numeral 404 in Fig. 4 indicates a sludge image when the chemical feeding rate relative to the flocculated sludge is excessive.

[0030] <Brightness histogram> After the sludge image acquisition unit 101 acquires the sludge image, the brightness histogram creation unit 102 creates a brightness histogram for the sludge image, which indicates the number of pixels in the same brightness range for each brightness range (S2: brightness histogram creation step). The brightness histogram creation unit 102 references the sludge image stored in the memory unit 13 and creates a brightness histogram for the entire sludge image.

[0031] Specifically, the luminance histogram creation unit 102 creates a luminance histogram by binarization processing. For example, the luminance histogram creation unit 102 converts pixels whose luminance values ​​are equal to or greater than a first luminance threshold and less than a second luminance threshold to white, and converts pixels whose luminance values ​​are less than the first luminance threshold or equal to or greater than the second luminance threshold to black. Here, consider the case where a set of the first luminance threshold and the second luminance threshold is represented by (first luminance threshold, second luminance threshold).

[0032] In this case, the brightness histogram creation unit 102 performs binarization processing using 32 pairs of first brightness thresholds and second brightness thresholds, for example, (0,6), (6,12), . . . , (180,186), and (186,192).The brightness histogram creation unit 102 then calculates the number of white pixels in the binarization processing for each pair and plots the calculated number of white pixels to create a brightness histogram, for example, as shown in FIG.

[0033] Fig. 5 is a diagram showing an example of a brightness histogram created by the brightness histogram creation unit 102 included in the information processing device 1 shown in Fig. 2. The brightness histogram shown in Fig. 5 shows the number of pixels in the same brightness range for each brightness range for one sludge image. Here, the same brightness range refers to, for example, the same set of brightness ranges for the brightness range (class) equal to or greater than the first brightness threshold and less than the second brightness threshold in each of the 32 sets. In the reference numerals 501 to 504 in Fig. 5, the horizontal axis indicates the brightness range of each of the 32 sets, and the vertical axis indicates the number of white pixels (pixels).

[0034] Reference numeral 501 in Fig. 5 indicates a brightness histogram corresponding to the sludge image indicated by reference numeral 401 in Fig. 4, and reference numeral 502 in Fig. 5 indicates a brightness histogram corresponding to the sludge image indicated by reference numeral 402 in Fig. 4. Reference numeral 503 in Fig. 5 indicates a brightness histogram corresponding to the sludge image indicated by reference numeral 403 in Fig. 4, and reference numeral 504 in Fig. 5 indicates a brightness histogram corresponding to the sludge image indicated by reference numeral 404 in Fig. 4.

[0035] Fig. 6 is a diagram showing the number of pixels having a brightness value of less than 66 in an example of a brightness histogram similar to the brightness histogram shown in Fig. 5. Fig. 7 is a diagram showing the number of pixels included in a first brightness range (a brightness range showing the maximum number of pixels) and a second brightness range (a brightness range near or adjacent to the first brightness range) in an example of a brightness histogram similar to the brightness histogram shown in Fig. 5. In Figs. 6 and 7, the vertical axis represents the number of pixels (pixels), and the number of pixels in each sludge image is shown aligned horizontally.

[0036] 6 and 7, the portions indicated by A1 and B1 are the number of pixels in each sludge image when the floc condition is good, the portions indicated by A2 and B2 are the number of pixels in each sludge image when the floc size is small, the portions indicated by A3 and B3 are the number of pixels in each sludge image when the chemical feeding rate relative to the flocculated sludge is insufficient, and the portions indicated by A4 and B4 are the number of pixels in each sludge image when the chemical feeding rate relative to the flocculated sludge is excessive.

[0037] When comparing the brightness histograms created by the brightness histogram creation unit 102, variations may occur even when the floc conditions are similar. However, even after subtracting such individual variations, it was found that the following characteristics exist in both the case where the chemical feeding rate relative to the flocculated sludge is insufficient and the case where the chemical feeding rate relative to the flocculated sludge is excessive.

[0038] As shown by dashed lines LA1, LA2, LA3, and LA4 in Figure 5, when the chemical feeding rate was insufficient (as indicated by reference numeral 503 in Figure 5), the number of pixels with low brightness values ​​was significantly smaller than in other cases. This is thought to be because sludge particles that could not be captured by the coagulant remain in the gaps between the flocs.

[0039] <Judging whether the drug injection rate is excessive or insufficient> After the brightness histogram creation unit 102 creates the brightness histogram, the determination unit 103 uses the brightness histogram to determine whether the chemical feeding rate for the flocculated sludge is insufficient (S3). As described above, when the chemical feeding rate is insufficient (as shown by reference numeral 503 in FIG. 5), the number of pixels with low brightness values ​​becomes significantly smaller than in other cases.

[0040] Therefore, it is preferable that the determination unit 103 determines that the drug injection rate is insufficient when the number of pixels in a predetermined brightness range in the brightness histogram is less than a predetermined first threshold. The predetermined brightness range and the predetermined first threshold are preset values. The predetermined brightness range is, for example, less than 66. The predetermined first threshold is, for example, 3000 pixels, as shown in FIG. 6.

[0041] To further improve the accuracy of the determination of whether the chemical injection rate is insufficient, the determination unit 103 may perform the determination as follows. Specifically, the determination unit 103 determines that the chemical injection rate is insufficient when, among a predetermined first number of recent sludge images, there are a predetermined second number or more sludge images in which the number of pixels in a predetermined brightness range is less than a predetermined first threshold. The predetermined first number is, for example, 10, and the predetermined second number is, for example, 7.

[0042] The inventors have found that when the drug injection rate is insufficient, the luminance histogram shows a tendency for the number of pixels in a predetermined luminance range to decrease. According to the information processing device 1 having the above configuration, the judgment unit 103 grasps such a tendency of the luminance histogram and then judges whether the drug injection rate is insufficient, so that the drug injection rate can be accurately judged.

[0043] Furthermore, in step S3, the predetermined brightness range is preferably a low brightness range below a predetermined brightness value. The predetermined brightness value is, for example, 66. As described above, when the drug injection rate is insufficient, the number of pixels in the predetermined brightness range in the brightness histogram decreases, and the inventors have found that such a predetermined brightness range tends to be a low brightness range. Therefore, the information processing device 1 configured as described above can more accurately determine whether the drug injection rate is insufficient.

[0044] When the determination unit 103 determines that the chemical feeding rate for the flocculated sludge is insufficient (YES in S3), it instructs the control device 2 to increase the chemical feeding rate (S4). The control device 2 increases the chemical feeding rate for the flocculated sludge by controlling the operation of the addition device 3. Then, the information processing device 1 ends the series of processes shown in Fig. 3. The chemical feeding rate may be increased by a predetermined amount, or the amount to be increased may be adjusted based on the degree of insufficiency of the chemical feeding rate.

[0045] This allows for easy adjustment of the chemical feeding rate. Also, the state of the flocculated sludge can be changed from an insufficient chemical feeding rate to an appropriate chemical feeding rate, thereby improving the efficiency of dewatering the flocculated sludge by the dehydrator 7.

[0046] When it is determined that the chemical feeding rate for the flocculated sludge is not insufficient (NO in S3), the determination unit 103 uses the brightness histogram to determine whether the chemical feeding rate for the flocculated sludge is excessive (S5). Here, consider the case where the chemical feeding rate for the flocculated sludge is excessive (the case shown by reference numeral 504 in FIG. 5). In this case, as shown by dashed lines L1 to L4 in FIG. 5, in the brightness range showing the maximum number of pixels, the number of pixels increases more rapidly as the brightness value increases, compared to other cases.

[0047] Furthermore, when the chemical feeding rate relative to the flocculated sludge is excessive, the shape of the brightness histogram is very close to a normal distribution. In particular, the shape of the left half of the brightness histogram is close to a normal distribution. In this regard, we consider what state the flocs are in when the chemical feeding rate is excessive.

[0048] When the chemical dosing rate is appropriate, the flocs are solid particles, like stones or potatoes. The particles have surfaces at various angles, and the way light hits each surface is different, so each surface is represented by pixels with different brightness values. In contrast, when the chemical dosing rate is too high, the entire floc is one soft mass, like rice cake, and is not separated into fine particles. Such flocs are pressed against the inspection window 54.

[0049] The surface of the flock pressed against the inspection window 54 is deformed to the inner shape (flat surface) of the inspection window 54, resulting in a uniform surface in terms of how light hits it, and is therefore represented by pixels with little variation in brightness values. For this reason, it is preferable that the determination unit 103 determines that the chemical injection rate is excessive when the number of pixels included in the first brightness range (the brightness range showing the maximum number of pixels) and / or the second brightness range (the brightness range near or adjacent to the first brightness range) in the brightness histogram exceeds a predetermined second threshold. In this case, the determination unit 103 determines that the chemical injection rate is excessive.

[0050] In other words, it is preferable that the determination unit 103 determine that the drug injection rate is excessive when the number of pixels included in at least one of the first and second luminance ranges exceeds a predetermined second threshold. The first luminance range is a luminance range showing the maximum number of pixels, for example, a range showing six luminance values ​​adjacent to each other in order of luminance value height. The second luminance range is a range including, for example, a range adjacent to the first luminance range in order of luminance value height and having a luminance value higher than the first luminance range, and a range adjacent to the first luminance range and having a luminance value lower than the first luminance range.

[0051] The combined range of the first and second luminance ranges is a range indicating three luminance ranges (=18 luminance values) adjacent to each other in descending order of luminance value. The predetermined second threshold is a preset value, and is, for example, 85,000 pixels as shown in Fig. 7. 85,000 pixels is the number of pixels that accounts for approximately one-third of the number of pixels of 260,130 pixels or less that are the subject of judgment by judgment unit 103.

[0052] 7, when the injection rate is excessive (as in the case of the portion shown in B4), the number of pixels included in the first luminance range and the second luminance range is the largest. However, even when the injection rate is insufficient (as in the case of the portion shown in B3), the number of pixels included in the first luminance range and the second luminance range is large.

[0053] When the drug injection rate is insufficient, the gaps may become brighter due to the uncaptured turbidity, and the color tone of the gaps may become closer to the color tone of the flocs, in which case the number of pixels included in the first brightness range and the second brightness range increases. However, because the determination of an insufficient drug injection rate can be easily performed using the predetermined brightness range in step S3, the determination in step S5 is performed excluding cases where the drug injection rate is insufficient.

[0054] The inventors have found that when the drug injection rate is excessive, the luminance histogram tends to show a rapid rise near the luminance range showing the maximum number of pixels. According to the information processing device 1 configured as described above, the determination unit 103 grasps such a tendency of the luminance histogram and then determines whether the drug injection rate is excessive, so that it is possible to accurately determine whether the drug injection rate is excessive.

[0055] When the determination unit 103 determines that the chemical feeding rate relative to the flocculated sludge is excessive (YES in S5), it instructs the control device 2 to reduce the chemical feeding rate (S6). The control device 2 reduces the chemical feeding rate relative to the flocculated sludge by controlling the operation of the addition device 3. Then, the information processing device 1 ends the series of processes shown in Fig. 3. The amount by which the chemical feeding rate is reduced may be a predetermined amount that has been set in advance, or the amount by which the chemical feeding rate is reduced may be adjusted based on the degree of excess.

[0056] This allows for easy adjustment of the chemical feeding rate. Also, since the state of the flocculated sludge can be changed from an excessive chemical feeding rate to an appropriate chemical feeding rate, the flocculator 5 can sufficiently agitate the sludge in the flocculation tank 51.

[0057] When the determination unit 103 determines that the chemical feeding rate relative to the flocculated sludge is not excessive (NO in S5), it determines that the state of the flocs is good (S7). Then, the information processing device 1 ends the series of processes shown in Fig. 3. In steps S3 to S7, the determination unit 103 determines whether the chemical feeding rate relative to the flocculated sludge is excessive or insufficient using the brightness histogram (determination step).

[0058] After excluding cases where the chemical feeding rate was insufficient in step S3 and then excluding cases where the chemical feeding rate was excessive in step S5, the number of pixels contained in the first and second brightness ranges was small in most of the remaining sludge images. However, when the floc condition was good (as in the case of the portion shown in B1), two sludge images were confirmed in which the number of pixels contained in the first and second brightness ranges exceeded 85,000 pixels, as shown in P1 and P2. The sludge image corresponding to P1 is shown as reference numeral 801 in Figure 8, and the sludge image corresponding to P2 is shown as reference numeral 802 in Figure 8.

[0059] Fig. 8 is a diagram showing an example of a sludge image and the number of pixels included in the first brightness range and the second brightness range. The sludge images indicated by reference numerals 801 and 802 in Fig. 8 are sludge images in which the gaps between flocs are small. The sludge image in which the gaps are small is an image in which flocs are momentarily pressed against the inspection window 54 due to the influence of the flow in the coagulation tank 51. Such an image does not show any undulations, so it has little variation in brightness values ​​and is thought to be similar to an image in which the chemical feeding rate is excessive.

[0060] In other words, a sludge image in which the number of pixels included in the first brightness range and the second brightness range is 85,000 or more is an image in which the chemical injection rate is excessive or the gap is small. Note that the detection frequency of the image can be used to distinguish between these two states.

[0061] When the chemical injection rate is excessive, sludge images with a pixel count of 85,000 or more pixels included in the first and second brightness ranges are frequently detected. In contrast, when the gap is small, sludge images with a pixel count of 85,000 or more pixels included in the first and second brightness ranges are less frequently detected.

[0062] Therefore, in step S5, the determination unit 103 executes the following determination. Specifically, the determination unit 103 determines that the chemical injection rate is excessive if, among a predetermined first number of recent sludge images, the number of sludge images having a pixel count of 85,000 or more in the first brightness range and / or the second brightness range is a predetermined second number or more. The predetermined first number is, for example, 10 images, and the predetermined second number is, for example, 7 images.

[0063] On the other hand, in step S5, if the number of sludge images with a pixel count of 85,000 or more included in the first brightness range and / or the second brightness range is less than the predetermined second number, the determination unit 103 determines in step S7 that the condition of the flocks is good.

[0064] Furthermore, reference numeral 803 in Fig. 8 indicates the number of pixels included in the first brightness range and the second brightness range. In reference numeral 803 in Fig. 8, the vertical axis indicates the number of pixels (pixels), and the number of pixels of each sludge image is shown aligned horizontally. The portion indicated by C1 is the number of pixels of each sludge image when the liquid portion of the flocculated sludge excluding flocs is cloudy, and the portion indicated by C2 is the number of pixels of each sludge image when the chemical feeding rate is excessive.

[0065] As shown by reference numeral 803 in Fig. 8, even in a sludge image where the liquid is cloudy, the number of pixels falling within the first and second brightness ranges tends to be large. This is because the color tone of the cloudy part may be very close to the color tone of the flocs, and in such cases, the number of pixels falling within the first and second brightness ranges increases.

[0066] However, such cases (where the color tones of the turbidity and the flocs are very similar) occur infrequently. Therefore, if a plurality of sludge images are used for the judgment, the judgment unit 103 can accurately judge whether the chemical injection rate is excessive even for sludge images that include turbidity.

[0067] In the above judgment, if the number of pixels in a predetermined brightness range (for example, less than 66) is less than the first threshold value (3,000 pixels), it is judged that the drug injection rate is insufficient, and if the number of pixels in the first brightness range and the second brightness range is greater than or equal to the second threshold value (85,000 pixels), it is judged that the drug injection rate is excessive.

[0068] The predetermined brightness range, the first threshold value, and the second threshold value may be set by an operator from an actual sludge image, or an algorithm may be created and used to automatically set the predetermined brightness range, the first threshold value, and the second threshold value so that (1) to (3) can be most appropriately identified by providing an image of (1) good flocs, (2) an image of flocs with an insufficient chemical feed rate, and (3) an image of flocs with an excessive chemical feed rate.

[0069] Through extensive research, the inventors have found that a tendency corresponding to the excess or deficiency of the chemical feeding rate appears in the brightness histogram. According to the information processing device 1 configured as described above, excess or deficiency of the chemical feeding rate can be determined from the brightness histogram, and the chemical feeding rate can be appropriately adjusted. Furthermore, an inappropriate sludge aggregation state, such as excess or deficiency of the chemical feeding rate, can be detected.

[0070] Furthermore, a device external to the information processing device 1 may automatically set the predetermined brightness range, the predetermined first threshold value, and the predetermined second threshold value based on the brightness histogram created by the brightness histogram creation unit 102. Furthermore, these setting processes performed by a device external to the information processing device 1 may be executed by a setting unit (not shown) included in the control unit 10 of the information processing device 1.

[0071] If the chemical feeding rate deviates significantly from the appropriate value, not only can obvious changes occur, such as flocs becoming larger when the chemical feeding rate is too high, or flocs becoming smaller when the chemical feeding rate is insufficient, but other changes can also occur. In this case, the following problems arise when the sludge image changes due to these other changes.

[0072] Specifically, the problem arises that evaluation of the color tone and floc size of the flocculated sludge by the control device 2 alone may not allow the flocculator 5 to sufficiently agitate the sludge in the coagulation tank 51, and the dehydrator 7 may not be able to sufficiently maintain the dehydration efficiency of the flocculated sludge. Even in such a case, the information processing device 1 configured as described above allows the flocculator 5 to sufficiently agitate the sludge in the coagulation tank 51, and the dehydrator 7 to sufficiently maintain the dehydration efficiency of the flocculated sludge.

[0073] Such effects will also contribute to achieving, for example, Goal 6 of the United Nations' Sustainable Development Goals (SDGs), which is to "Ensure availability and sustainable management of water and sanitation for all."

[0074] In addition, in the above embodiment, an example has been described in which the information processing device 1 and the control device 2 are independent devices, but these may be combined into one or two devices. Furthermore, some of the processes executed by these devices may be executed by other information processing devices. In this way, the entity that executes each process described in the above embodiment can be changed as appropriate, and the water treatment system 100 can be realized with various system configurations. For example, each process shown in FIG. 3 can be executed by sharing the work among multiple information processing devices.

[0075] 〔summary〕 The information processing device according to aspect 1 of the present invention includes a sludge image acquisition unit that acquires a sludge image captured by an imaging device of flocculated sludge, which is formed by aggregating solid suspended matter in the sludge and consists of multiple overlapping flocs; a brightness histogram creation unit that creates a brightness histogram for the sludge image, which shows the number of pixels in the same brightness range for each brightness range; and a determination unit that uses the brightness histogram to determine whether the chemical dosing rate for the flocculated sludge is excessive or insufficient.

[0076] In the information processing device according to aspect 2 of the present invention, in the above aspect 1, the judgment unit may determine that the drug injection rate is insufficient if the number of pixels in a predetermined brightness range in the brightness histogram is less than a predetermined first threshold.

[0077] In the information processing device according to aspect 3 of the present invention, in the above aspect 2, the predetermined luminance range may be a low luminance range.

[0078] In the information processing device according to aspect 4 of the present invention, in aspect 2 or 3 above, the judgment unit may instruct a control device that controls the drug injection rate to increase the drug injection rate when it determines that the drug injection rate is insufficient.

[0079] In an information processing device according to aspect 5 of the present invention, in any of aspects 1 to 4 above, the judgment unit may determine that the drug injection rate is excessive if the number of pixels included in a first brightness range indicating the maximum number of pixels and / or a second brightness range near the first brightness range in the brightness histogram exceeds a predetermined second threshold.

[0080] In an information processing device according to aspect 6 of the present invention, in the above-mentioned aspect 5, the judgment unit may instruct a control device that controls the drug injection rate to reduce the drug injection rate when it determines that the drug injection rate is excessive.

[0081] A water treatment system according to aspect 7 of the present invention may be any of aspects 1 to 6 above, and may include an addition device that adds an agent that coagulates suspended solids to sludge in a coagulation tank, an imaging device that photographs the coagulated sludge in the coagulation tank, an information processing device that determines whether the chemical dosing rate is excessive or insufficient from the image taken by the imaging device, and a presentation device that presents an increase or decrease in the chemical dosing rate depending on the determination result regarding the excess or deficiency of the chemical dosing rate.

[0082] A chemical feeding rate determination method according to aspect 8 of the present invention is a chemical feeding rate determination method executed by one or more information processing devices, and includes a sludge image acquisition step of acquiring, as a sludge image, an image of flocculated sludge formed by aggregating solid floating matter in the sludge and consisting of multiple overlapping flocs; a brightness histogram creation step of creating, for the sludge image, a brightness histogram showing the number of pixels in the same brightness range for each brightness range; and a determination step of using the brightness histogram to determine whether the chemical feeding rate for the flocculated sludge is excessive or insufficient.

[0083] The information processing device according to any one of aspects 1 to 6 of the present invention may be realized by a computer. In this case, the drug injection rate determination program of the information processing device that causes the computer to operate as each part (software element) of the information processing device, thereby realizing the information processing device on the computer, and the computer-readable recording medium on which the program is recorded, also fall within the scope of the present invention.

[0084] [Software implementation example] The functions of the information processing device 1 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly each part included in the control unit 10).

[0085] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing each function described in the above embodiment.

[0086] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0087] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0088] Furthermore, each process described in the above embodiment may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0089] <Additional Notes> The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0090] 1. Information processing equipment 2. Control device 3 Addition device 6 Presentation device 42 Imaging equipment 100 Water Treatment Systems 101 Sludge image acquisition unit 102 Brightness histogram creation section 103 Judgment section

Claims

1. a sludge image acquisition unit that acquires a sludge image taken by an image capture device of flocculated sludge, which is formed by flocculating solid suspended matter in the sludge and overlapping multiple flocs; a brightness histogram creation unit that creates a brightness histogram for the sludge image, the brightness histogram indicating the number of pixels in the same brightness range for each brightness range; a determination unit that determines whether a chemical feeding rate for the flocculated sludge is excessive or insufficient using the brightness histogram.

2. The information processing device according to claim 1 , wherein the determining unit determines that the drug injection rate is insufficient when the number of pixels in a predetermined brightness range in the brightness histogram is less than a predetermined first threshold value.

3. The information processing device according to claim 2 , wherein the predetermined luminance range is a low luminance range.

4. The information processing device according to claim 2 , wherein the determining unit, when determining that the drug injection rate is insufficient, instructs a control device that controls the drug injection rate to increase the drug injection rate.

5. 2. The information processing device according to claim 1, wherein the determination unit determines that the drug injection rate is excessive when the number of pixels included in a first brightness range indicating the maximum number of pixels and / or a second brightness range near the first brightness range in the brightness histogram exceeds a predetermined second threshold.

6. The information processing device according to claim 5 , wherein the determining unit instructs a control device that controls the drug injection rate to reduce the drug injection rate when the determining unit determines that the drug injection rate is excessive.

7. an adding device that adds an agent that coagulates suspended solids to the liquid to be treated in the coagulation tank; an imaging device for imaging the flocculated sludge in the flocculation tank; an information processing device according to any one of claims 1 to 6, which determines whether a drug injection rate is excessive or insufficient from an image captured by the imaging device; a presentation device that presents an increase or decrease in the chemical feeding rate depending on the determination result regarding an excess or deficiency of the chemical feeding rate.

8. A drug injection rate determination method executed by one or more information processing devices, a sludge image acquisition step of acquiring, as a sludge image, an image of flocculated sludge formed by flocculating solid suspended matter in the sludge and overlapping a plurality of flocs; a brightness histogram creation step of creating a brightness histogram for the sludge image, the brightness histogram indicating the number of pixels in the same brightness range for each brightness range; a determining step of determining whether the chemical feeding rate for the flocculated sludge is excessive or insufficient using the brightness histogram.

9. 2. A chemical injection rate determination program for causing a computer to function as the information processing device according to claim 1, the chemical injection rate determination program causing a computer to function as the sludge image acquisition unit, the brightness histogram creation unit, and the determination unit.

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