Solid-liquid separation device, solid-liquid separation liquid monitoring device

Abstract

To provide a solid-liquid separator capable of automatically determining whether or not a coagulant chemical injection condition is appropriate, and a monitoring device for the separated liquid of the solid-liquid separator.SOLUTION: A solid-liquid separator of the present invention includes a chemical injection device for adding a coagulant to a process liquid containing solids, a separator for separating the process liquid from solid-liquid, a monitoring unit for acquiring image data of bubbles of separate liquid discharged from the separator, a separate liquid monitor including a judgment unit that judges the chemical injection condition of the coagulant from at least the amount of bubbles in the separate liquid.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a solid-liquid separator for separating a treatment liquid containing solids into solid and liquid, and a separated liquid monitoring device for the solid-liquid separator. [Background technology]

[0002] A centrifugal separator known as a decanter is known as a device for performing solid-liquid separation of a treated liquid containing solids. Decanters are installed, for example, in sewage treatment facilities, and perform solid-liquid separation of treated liquid derived from sewage containing sludge into dehydrated cake and separated liquid. Figure 12 shows a schematic diagram of the basic structure of a decanter. A horizontal decanter 1 includes a bowl 11 and a screw conveyor 12 that rotate around a horizontal axis. Although not shown, a vertical decanter in which the bowl 11 and screw conveyor 12 rotate around a vertical axis is also known.

[0003] The bowl 11 is a cylindrical body with one or both ends formed into a conical shape. The screw conveyor 12 is equipped with screw blades 12a that transport the solids resulting from solid-liquid separation in the bowl 11. The screw conveyor 12 is hollow along its central axis of rotation, and a supply nozzle 13 for the treated liquid to be centrifuged is inserted with a slight clearance so as not to come into contact with the screw conveyor 12. After a flocculant is added to the centrifuged treated liquid, the treated liquid is supplied to the decanter 1 through the supply nozzle 13. The treated liquid discharged from the tip of the supply nozzle 13 is supplied to a treated liquid chamber in the screw conveyor 12, and is then discharged by centrifugal force from a supply port 14 formed on the outer periphery and supplied into the bowl 11.

[0004] In this configuration, treated sewage-derived liquid that has been treated in a settling tank or the like within a sewage treatment facility is continuously supplied into bowl 11, and when bowl 11 is rotated at a predetermined rotation speed, the treated liquid is separated into a solid phase and a liquid phase within bowl 11 by the action of centrifugal force. The solids are transported toward one end of bowl 11 by screw conveyor 12, separate from the liquid in the conical portion, and are discharged as dehydrated cake through solids outlet 15. Meanwhile, the liquid phase (separated liquid) overflows and is discharged from separated liquid outlet 16 on the opposite side.

[0005] The control factors for obtaining dehydrated cake with the desired moisture content in the decanter 1 described above include the centrifugal force set by the rotational speed of the bowl 11, the differential speed between the bowl 11 and the screw conveyor 12, the torque value of the screw conveyor 12, and the amount of flocculant added as a chemical. In recent years, control technologies that use artificial intelligence (AI) to adjust these control factors to appropriate values ​​have been developed. Therefore, there is a need for a method that can automatically determine whether the flocculant dosing conditions are appropriate, for example, using a computer that constitutes the control unit. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6938159 [Patent Document 2] Patent No. 7236190 [Patent Document 3] Japanese Patent Application Publication No. 5-177153 [Patent Document 4] Patent No. 6701251 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made based on these circumstances, and its purpose is to provide a solid-liquid separation device that can automatically determine the flocculant dosing conditions, and a separated liquid monitoring device for the solid-liquid separation device. [Means for solving the problem]

[0008] The gist of the present invention is as follows. (1) The solid-liquid separation device of the present invention is characterized by comprising: a chemical injection device that adds a flocculant to a treatment liquid containing solids; a separation device that separates the treatment liquid into solids and liquids; a monitoring unit that acquires image data of bubbles in the separation liquid discharged from the separation device; and a separation liquid monitoring device that includes a judgment unit that judges the chemical injection conditions for the flocculant from at least the amount of bubbles in the separation liquid in the image data acquired by the monitoring unit. (2) The separation liquid monitoring device is equipped with a monitoring unit that acquires image data of the solid content remaining in the separation liquid, and determines the flocculant dosing conditions based on at least the amount of bubbles in the separation liquid, the amount of solid content in the separation liquid, and / or the size of the flocculant particles. (3) The judgment result output by the separation liquid monitoring device includes any one of the following: appropriate chemical supply amount, excessive chemical supply amount, insufficient chemical supply amount, appropriate chemical supply amount but poor agglutination reaction state. (4) The monitoring unit for acquiring image data of bubbles in the separated liquid is disposed in a liquid receiving box that discharges the separated liquid, and acquires image data of the separated liquid discharged into the liquid receiving box. (5) The monitoring unit that acquires image data of the solid content remaining in the separated liquid acquires the image data of the separated liquid through a transparent member that constitutes a part of the flow path through which the separated liquid flows. (6) The monitoring unit that acquires image data of the solid content remaining in the separated liquid further includes a pump that samples the separated liquid and a back pressure valve provided on the discharge side of the pump, and acquires image data of the separated liquid between the pump and the back pressure valve through the transparent member. (7) The separated liquid monitoring device for a solid-liquid separation device of the present invention is characterized by comprising a monitoring unit that acquires image data of the separated liquid discharged from a separation device that separates a treatment liquid containing solids into solids and liquids, and an output unit that analyzes the image data acquired by the monitoring unit and outputs information on the amount of bubbles in the separated liquid. [Effects of the Invention]

[0009] According to the present invention, by using image data of bubbles in the separated liquid discharged from the solid-liquid separator as the judgment material, it is possible to analyze the image data using, for example, a computer and judge whether the flocculant injection conditions are appropriate. Therefore, this can contribute to the realization of automatic control of solid-liquid separators using artificial intelligence (AI), which has been developed in recent years.

[0010] Furthermore, according to the present invention, by focusing on the amount of bubbles in the separated liquid, it becomes possible to accurately determine whether the current chemical supply conditions for the flocculant are appropriate. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a sewage treatment facility in which a decanter according to a first embodiment of the present invention is arranged. [Figure 2] FIG. 2 is a vertical cross-sectional view of the decanter. [Figure 3] FIG. 2 is a diagram showing the configuration of a monitoring device for the separated liquid discharged from the decanter. [Figure 4] 10A and 10B are images of solid content in the separated liquid discharged from the decanter, images of bubbles in the separated liquid, and a list of the determination results of the chemical injection conditions. [Figure 5] FIG. 10 is a photograph of bubbles in the separated liquid discharged from the decanter. [Figure 6] This is a diagram of the separated liquid flowing through the flow path, captured through a sight glass. [Figure 7] FIG. 10 is a photograph of bubbles in the separated liquid discharged from the decanter. [Figure 8]10 is a list of the determination results of the chemical injection conditions and the decanter operating conditions. [Figure 9] FIG. 10 is a configuration diagram of a separated liquid monitoring device according to a second embodiment. [Figure 10] FIG. 10 is a decision flow chart of a separated liquid monitoring device according to a third embodiment. [Figure 11] FIG. 10 is a diagram illustrating a determination flow of a separated liquid monitoring device according to a fourth embodiment. [Figure 12] FIG. 1 is a diagram showing the configuration of a conventional centrifugal separator. DETAILED DESCRIPTION OF THE INVENTION

[0012] A solid-liquid separator and a separated liquid monitoring device for a solid-liquid separator according to preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the technical scope of the present invention should not be construed as being limited by the embodiments described below.

[0013] [First embodiment] (Overall configuration) FIG. 1 is a schematic diagram of a sewage treatment facility 3 equipped with a decanter 2, a preferred example of a solid-liquid separation device. The sewage treatment facility 3 can be broadly divided into a water treatment facility and a sludge treatment facility. The water treatment facility is composed of equipment such as a primary settling tank 31, an aeration tank, and a final settling tank. For ease of illustration, the aeration tank and final settling tank are shown as the "downstream process." Sewage collected from sewage collection areas, such as municipalities, is supplied to the primary settling tank 31 for solid-liquid separation into supernatant and primary sludge. The supernatant is transferred to an aeration tank, and the primary sludge is sent to a sludge treatment facility. The supernatant from the primary settling tank 31 is supplied to the aeration tank, where it is biologically treated by activated sludge. A portion of the activated sludge produced is supplied to the final settling tank for solid-liquid separation into supernatant and primary sludge. The supernatant is further detoxified before being discharged, and part of the settled sludge is returned to the aeration tank, while the rest is sent to a sludge treatment facility as excess sludge.

[0014] A sludge treatment facility treats sludge generated in the aforementioned water treatment facility and is composed of thickening equipment, digestion equipment, dewatering equipment, etc. Figure 1 shows an example of a separation and thickening system. In this case, primary sludge from the primary settling tank 31 is gravity thickened in a gravity thickening tank 32, and excess sludge from the final settling tank is mechanically thickened in a mechanical thickener 33. The mechanical thickener 33 is typically a belt-type filter thickener, but a decanter-type centrifugal thickener may also be used. The sludge thickened in the gravity thickener 32 and mechanical thickener 33 (thickened sludge) is supplied from the thickened sludge tank 34 via a supply pump 35 to a decanter 2, which serves as a dewatering machine, or is supplied to the decanter 2 after digestion.

[0015] Decanter 2 separates sludge (thickened sludge), an example of a treatment liquid, into a dehydrated cake and a separated liquid. The dehydrated cake discharged from decanter 2 is then supplied to incinerator 37 via transfer equipment 36, such as a pressure pump or a transport conveyor, and incinerated. Treatment other than incineration may also be used. Meanwhile, the separated liquid discharged from decanter 2 is collected in separated liquid collection tank 38 via separated liquid monitoring device 4, which will be described in detail later. The clear separated liquid is detoxified, if necessary, and then released.

[0016] The operation of each piece of equipment in the sewage treatment facility 3 is centrally controlled, for example, by a computer in a central control room 39. An operator can communicate with the central control room 39 using, for example, a terminal 30. However, the overall configuration of the sewage treatment facility 3 shown in Figure 1 is just one example, and the equipment configuration and treatment method are not limited thereto.

[0017] As shown in Figure 2, decanter 2 includes a casing 2a having a solids outlet 20 and a separated liquid outlet 21 on its underside, a bowl 5 disposed within the casing 2a, a screw conveyor 6 for transporting the solids centrifuged within the rotating bowl 5, and a pipe-like feed tube 7 for supplying the centrifuged treated liquid into bowl 5. Both shafts of bowl 5 are supported by a bearing mechanism 22 such as a bearing disposed outside the casing 2a. Furthermore, both shafts of screw conveyor 6 are supported by a bearing mechanism 23 such as a conveyor bearing. Reference numeral 24 denotes a partition wall that divides the space within the casing 2a.

[0018] When the power of the main motor 25, which is a driving device, is transmitted to the pulley 25b on the bowl 5 side via the rotating belt 25a, the bowl 5 rotates, and the rotational power is further transmitted to the screw conveyor 6 via the gear box 26 and spline shaft 26a, which are differential speed generating devices, so that the bowl 5 and the screw conveyor 6 rotate at a relative differential speed. This can be adjusted as appropriate depending on the type and concentration of the processing liquid, but as an example of normal operation, it is set to 500 to 8000 min -1 The bowl 5 is rotated at a predetermined rotation speed selected within the range of 0.5 to 50 min -1 By rotating the screw conveyor 6 at a relative speed difference of 2 to 25 m, the treated liquid is separated into solids and separated liquid. 3 / Hr into the bowl 5.

[0019] A motor called a backdrive motor 27 is connected to the gearbox 26 via a rotating belt 27a and a pulley 27b. The backdrive motor 27 applies a brake so that the screw conveyor 6 rotates slower than the bowl 5. Regenerative power generated in the backdrive motor 27 by applying the brake can be supplied to the main motor 25. However, the backdrive motor 27 is not necessarily provided. Reference numeral 28 denotes a support frame for the decanter 2, and reference numeral 29 denotes a support member for supporting the feed tube 7.

[0020] Bowl 5 has a conical portion 51 at one end of its cylindrical body, and a disk-shaped member called a front hub 52 at the other end. The body of bowl 5 forms a pool (liquid reservoir) for the treatment liquid supplied into bowl 5. Meanwhile, conical portion 51 forms a beach portion where solids transported by screw conveyor 6 separate from the liquid phase, and is provided with a solids discharge port 53 at its end. Front hub 52 is provided with a separated liquid discharge port 54 through which the separated liquid overflows and is discharged. Separated liquid discharge port 54 is, for example, a circular opening that penetrates front hub 52.

[0021] A spiral screw blade 61 for transporting solid content is provided on the outer peripheral surface of the screw conveyor 6. Furthermore, a treatment liquid supply port 62 is provided on the outer peripheral surface of the screw conveyor 6. The treatment liquid supply port 62 communicates with a treatment liquid supply chamber 63 formed inside the screw conveyor 6.

[0022] The feed tube 7 approaches or is inserted into the processing liquid supply chamber 63 without coming into contact with the rotating bowl 5 and screw conveyor 6. At the entrance of the processing liquid supply chamber 63, an upright wall 64 is formed along the circumferential direction to act as a liquid barrier to prevent the supplied processing liquid from flowing back out. Meanwhile, the base end of the feed tube 7 is connected to the supply pump 35 (see FIG. 1) via a flow path 71. The processing liquid sent from the supply pump 35 is discharged from the tip of the feed tube 7 into the processing liquid supply chamber 63. The processing liquid supplied into the processing liquid supply chamber 63 is discharged from the processing liquid supply port 62 and supplied into the bowl 5 by the action of the centrifugal force of the rotating screw conveyor 6.

[0023] Next, we will explain the chemical injection device 8 that adds a liquid flocculant, which is an example of a chemical solution, to the treatment liquid. The decanter 2 of this embodiment is configured to be able to add the flocculant by either external or internal chemical injection. A preferred example of external chemical injection is line chemical injection. Specifically, chemical injection nozzles 80A, 80B, and 80C are arranged in the treatment liquid flow path 71 (e.g., piping). A plurality of chemical injection nozzles 80A, 80B, and 80C are provided so that the flocculation reaction time (i.e., the time until the treatment liquid with added flocculant is supplied to the decanter 2) can be changed.

[0024] Although three chemical injection nozzles 80A, 80B, and 80C are provided in FIG. 2, the number of nozzles may be changed as needed. The chemical injection nozzle 80A, 80B, or 80C from which the flocculant is added is switched by opening or closing valves 81A, 81B, and 81C. However, it is not necessary to select only one; two or more of the chemical injection nozzles 80A, 80B, and 80C may be used for addition. In this case, the ratio of the amounts added may be adjusted by adjusting the valve opening. The opening and closing or opening adjustment of valves 81A, 81B, and 81C may be performed automatically by the control unit 9 of the decanter 2 or manually by an operator. However, whether or not to switch the chemical injection position, etc., is determined based on the chemical injection conditions, such as the chemical injection position, determined based on information from the separated liquid monitoring device 4.

[0025] The distance from decanter 2 to the addition position of chemical injection nozzle 80A (i.e., the length of flow path 71) is, for example, 10 m. The distance from decanter 2 to the addition position of chemical injection nozzle 80B (i.e., the length of flow path 71) is, for example, 3 to 5 m. The distance from decanter 2 to the addition position of chemical injection nozzle 80C (i.e., the length of flow path 71) is, for example, 1 m. The aggregation reaction time is determined by the respective distances and the flow rate of the treatment liquid (= flow rate × distance). In other words, chemical injection nozzles 80A, 80B, and 80C and valves 81A, 81B, and 81C are one example of means for adjusting the addition position of the flocculant. A means for enhancing the stirring effect, such as a line mixer or a mixing valve, may be provided downstream of the addition position of the flocculant.

[0026] On the other hand, in-machine chemical feeding is performed, for example, using a feed tube 7. The feed tube 7 has a double-pipe structure in which a flow path 72 through which the treatment liquid flows is formed in the center and a flow path 73 through which the flocculant flows, surrounding the outer periphery of the flow path 72. A flocculant flow path 82 (e.g., a pipe) is connected to the flow path 73 so as to communicate with the flow path 73, and a valve 81D is further provided in the flow path 82. Therefore, by opening and closing the valves 81A, 81B, 81C, and 81D, it is possible to switch between in-machine chemical feeding and external chemical feeding. The flocculant may be added by both in-machine chemical feeding and external chemical feeding by adjusting the valve opening.

[0027] A flocculant outlet is formed at the tip of the feed tube 7, separate from the central treatment liquid outlet. The flocculant outlets are, for example, circular openings formed radially through the peripheral surface of the tip of the feed tube 7. Meanwhile, the interior of the screw conveyor 6 is divided into a treatment liquid supply chamber 63 and a flocculant supply chamber 65 via a partition wall 64. The flocculant supply chamber 65 is a supply chamber with a groove-shaped cross section formed around the entire inner peripheral surface of the hollow of the screw conveyor 6, and can receive the flocculant discharged radially from the feed tube 7. Furthermore, a flocculant outlet 66 is formed at the bottom of the flocculant supply chamber 65. The flocculant outlet 66 is, for example, a circular opening radially through the screw conveyor 6. That is, like the treatment liquid, the flocculant can be supplied into the bowl 5 by utilizing the centrifugal force of the rotating screw conveyor 6.

[0028] A flow meter 83 is provided in the flocculant flow path 82 so that the flow rate of the flocculant delivered by the flocculant supply pump 84 can be measured. A flow rate control unit 85 adjusts the discharge flow rate of the flocculant supply pump 84, for example, by feedback control, so that the flow rate measured by the flow meter 83 becomes the target flow rate. The flocculant supply pump 84 is, for example, a metering pump or a pump with variable output using an inverter. In other words, the flow meter 83 and the flocculant supply pump 84 are one example of a means for adjusting the chemical injection amount. However, the flow rate adjustment using the flow meter 83 and the flocculant supply pump 84 is one example, and other configurations may be used as long as the flow rate can be adjusted. One example of another configuration is to provide a flow rate adjustment valve in the flow path 82.

[0029] The base end of the flocculant flow path 82 is connected via a flocculant supply pump 84 to a tank 86 storing a flocculant solution. The flocculant is, for example, a polymer-based flocculant. The polymer-based flocculant can be an amphoteric polymer, an anionic polymer, or a cationic polymer, or a combination thereof. Preferred examples of polymer-based flocculants include one or more of dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and polyvinylamidine. The polymer-based flocculant solution can be generated, for example, using a dissolution device that dissolves a solid polymer-based flocculant in a solvent (e.g., water) to generate a solution. The polymer-based flocculant for on-board and off-board chemical injection may be the same type, or different types may be supplied from separate sources. A configuration for adding an inorganic flocculant to the treatment liquid may also be added.

[0030] 3, the separated liquid monitoring device 4 is provided midway along a flow path 21a (e.g., a pipe) for the separated liquid discharged from the separated liquid outlet 21 of the decanter 2. When multiple decanters 2 are provided within the sewage treatment facility 3, a separated liquid monitoring device 4 may be provided for each decanter 2, or a separated liquid monitoring device 4 may be provided at a location where the separated liquids discharged from multiple decanters 2 join together.

[0031] As a preferred example, the separated liquid monitoring device 4 includes a monitoring unit 40 that monitors the state of the separated liquid flowing in the flow path 21 a and a monitoring unit 42 that monitors the state of the separated liquid discharged into the liquid receiving box 41 .

[0032] In a preferred example, the monitoring unit 40 determines the presence or absence of solids remaining in the separated liquid, the amount of solids, and the size of aggregated particles. Specifically, sight glasses 43A and 43B are arranged in the flow path 21a, and monitoring cameras 44A and 44B are installed at positions facing the glass windows of the sight glasses 43A and 43B, respectively. The monitoring cameras 44A and 44B capture images of the separated liquid flowing through the flow path 21a to obtain image data. The monitoring cameras 44A and 44B are, for example, CCD cameras. In the example of FIG. 3, two sets of sight glasses 43A and 43B and monitoring cameras 44A and 44B are provided, and either one can be switched by opening or closing valves 45A and 45B. The image data obtained by the monitoring cameras 44A and 44B is transmitted to, for example, the control unit 9 of the decanter 2 (see FIG. 2). The sight glasses 43A and 43B are an example of a transparent member that constitutes part of the flow path.

[0033] The monitoring unit 42 determines the state of foam in the separated liquid discharged into the liquid receiving box 41, which is an example of a monitoring box. It may also determine the color of the foam. Specifically, the end of the flow path 21a is connected to the box-shaped liquid receiving box 41, allowing the separated liquid to be discharged into the liquid receiving box 41. The monitoring cameras 46A and 46B located above capture images of the separated liquid, such as foam on the liquid surface. However, this is not limited to foam on the liquid surface. For example, the monitoring cameras 46A and 46B may capture images of the line where the valves 45A and 45B are open. The monitoring cameras 46A and 46B may be, for example, CCD cameras. Foam is generated due to residual flocculant in the separated liquid. This is particularly likely to occur with polymer-based flocculants. The amount of foam is roughly proportional to the concentration of the remaining flocculant. However, experiments have confirmed that the amount of foam no longer changes once a certain concentration is exceeded.

[0034] Image data acquired by monitoring cameras 46A and 46B is sent to, for example, the control unit 9 of decanter 2 (see FIG. 2). Meanwhile, the separated liquid discharged into liquid receiving box 41 is discharged from outlet 47 provided on the bottom side of the box and collected in separated liquid tank 38 or the like (see FIG. 1). If the amount of treated liquid in decanter 2 is large, flow path 21a may be branched to sample a portion of the separated liquid and introduce it into separated liquid monitoring device 4. In the example of FIG. 3, monitoring unit 40 and monitoring unit 42 are configured with two sets of monitoring lines (sight glass 43A-monitoring camera 44A-monitoring camera 46A, and sight glass 43B-monitoring camera 44B-monitoring camera 46B), but either one may be used. Monitoring cameras 44A and 44B and monitoring cameras 46A and 46B may be equipped with flash functions, or separate lights that are turned on when capturing images may be provided.

[0035] Based on the image data sent from the monitoring cameras 44A, 44B and 46A, 46B, the control unit 9 outputs at least one of the following judgment results: appropriate drug injection amount, excessive drug injection amount, insufficient drug injection amount, or appropriate drug injection amount but poor agglutination reaction state. In the example shown below, the judgment results are output in more detail: "appropriate drug injection amount and appropriate agglutination reaction state," "appropriate drug injection amount and inappropriate agglutination reaction state," "excessive drug injection amount and appropriate agglutination reaction state," "excessive drug injection amount and inappropriate agglutination reaction state," and "insufficient drug injection amount." Of course, the types of judgment results can be changed or added as appropriate. To make such judgments, a computer equipped with AI functions is required to load more image data and perform deep learning, etc., but the judgment system is as follows. The control unit 9 that executes these judgments is preferably a computer in the central control room 39, for example. Alternatively, it may be a dedicated computer, the control panel of the decanter 2, or the control panel of the separated liquid monitoring device 4.

[0036] The monitoring cameras 44A and 44B capture images of the separated liquid to obtain image data of the solid content in the separated liquid. The state of the solid content remaining in the separated liquid varies depending on its concentration and the quality of the agglutination reaction. FIG. 4 shows examples of image data of each separated liquid prepared by changing the solid content concentration and the amount of flocculant added. FIG. 4 shows the state of the separated liquid in each case (Cases A1 to A6), which will be described in detail later. Meanwhile, the monitoring cameras 46A and 46B capture images of the separated liquid being discharged into the liquid receiving box 41 to obtain image data of, for example, bubbles in the separated liquid in the liquid receiving box 41. FIG. 5 shows image data with a small amount of bubbles, an appropriate amount of bubbles, and a large amount of bubbles. FIG. 4 also shows image data of bubbles corresponding to each case. FIG. 6 shows image data of the separated liquid actually flowing through the flow path 21a, captured through a sight glass. As shown in FIG. 6, it was confirmed that image data capable of identifying the solid content and size in the separated liquid flowing through the flow path 21a could be obtained. As described above, image data of bubbles in the separated liquid may be obtained by capturing images of bubbles on the surface of the separated liquid in the liquid receiving box 41, or by capturing images of bubbles in the separated liquid flowing down into the liquid receiving box 41. Figure 7 shows an example in which images of the separated liquid flowing down into the liquid receiving box 41 are continuously captured and analyzed by a computer. As an example, a graphic display such as that shown in Figure 7 may be output so that an operator can check it. The amount of foam is determined to be low, appropriate, or high, for example, based on the area of ​​the bubbles in the separated liquid flowing down. If the amount of foam changes over time, the amount of foam may be determined, for example, by using a moving average.

[0037] As shown in Figure 4, when the state of the separated liquid is examined, for example, at a solids concentration of 400 mg / L, in the case of no chemical injection, the solids are dispersed in a sol-like state in the liquid. In contrast, in the case of separated liquid that has been centrifuged after chemical injection, the solids are aggregated. However, the size of the aggregated particles (e.g., aggregated particle diameter) increases in the order of insufficient chemical injection, appropriate chemical injection, and excessive chemical injection. When the chemical injection amount is appropriate, it can be further subdivided into cases where the amount of foam is appropriate but the aggregated particle diameter is large, and cases where the aggregated particle diameter is small. When the chemical injection amount is excessive, it can be further subdivided into cases where the amount of foam is large but the aggregated particle diameter is small, and cases where the amount of foam is large and the aggregated particle diameter is large. The same is true for other concentrations (100 mg / L, 2000 mg / L).

[0038] The control unit 9, which has AI capabilities, determines which of the cases shown in FIG. 4 applies based on the acquired image data and outputs the result. To do this, the control unit 9 first determines whether the agglomerated particles are small or large based on the image data sent from the monitoring cameras 44A and 44B. This determination, for example, is made by determining whether a predetermined size threshold is set and whether the agglomerated particles in the acquired image data are larger than this threshold. The size of the agglomerated particles may be determined, for example, by the agglomerated particle diameter. In this case, the average particle diameter of a portion of the agglomerated particles sampled from the image may be used instead of the average particle diameter of all the agglomerated particles captured in the image. Furthermore, it is sufficient to be able to determine / compare the size of the agglomerated particles from the image data; it is not necessary to determine the particle diameter. The same applies to the determination flow described below. Furthermore, the control unit 9 determines whether the amount of foam is low, the amount of foam is appropriate, or the amount of foam is high based on the image data sent from the monitoring cameras 46A and 46B. For example, this determination is made by setting a predetermined appropriate range for the area of ​​bubbles captured within the imaging range of the monitoring cameras 46A and 46B, and determining that the amount of bubbles is appropriate if the area of ​​bubbles in the acquired image data is within this range, that the amount of bubbles is small if it is below this range, and that the amount of bubbles is large if it is above this range. An appropriate range may also be set for the agglomerate particle size.

[0039] Then, in case A1, the control unit 9 determines that chemical injection needs to be started. In case A2, where the agglutinant particle size is small and the amount of foam is small, the control unit 9 determines that the chemical injection amount is insufficient. In case A3, where the agglutinant particle size is small but the amount of foam is appropriate, the control unit 9 determines that the chemical injection amount is appropriate and the agglutination reaction state is inappropriate. In case A4, where the agglutinant particle size is large and the amount of foam is appropriate, the control unit 9 determines that the chemical injection amount is appropriate and the agglutination reaction state is appropriate. In case A5, where the agglutinant particle size is small and the amount of foam is excessive, the control unit 9 determines that the chemical injection amount is excessive and the agglutination reaction state is inappropriate. In case A6, where the agglutinant particle size is large and the amount of foam is excessive, the control unit 9 determines that the chemical injection amount of the agglutinant is appropriate and the agglutination reaction state is appropriate. That is, the control unit 9 functions as a determination unit that determines whether the chemical injection amount of the agglutinant and / or the agglutination reaction state is appropriate based on the monitoring information from monitoring units 40 and 42.

[0040] Of course, cases A1 to A6 in Figure 4 are just examples, and by loading more image data into a computer equipped with AI functions, it is possible to subdivide the cases into many more cases. This also makes it possible to quantitatively determine whether the amount of drug injection is insufficient or excessive.

[0041] Furthermore, the control unit 9 may automatically take appropriate action for each of the cases A1-A6 or issue a command to the operator's terminal 30 to take appropriate action. That is, the control unit 9 functions as an operation control unit. For example, in case A1, the chemical injection device 8 is activated. For example, in case A2, the flow rate of the coagulant controlled by the flow rate control unit 85 is increased. For example, in case A3, the flow rate of the coagulant controlled by the flow rate control unit 85 is maintained, and the valves 81A-81D are switched to change the coagulant addition position. The coagulation reaction state is not necessarily improved simply by a longer reaction time. For example, the properties of the sewage collected in the sewage treatment facility 3 vary from day to day, and the properties of the treated sludge are also not constant. In addition, in the case of the decanter 2, if the coagulated particle size becomes too large, the coagulated particles may be broken by hitting the rotating screw blades 61 under high-speed rotation conditions with high centrifugal force. Furthermore, whether external or internal chemical injection is appropriate varies from day to day. In other words, which chemical injection position is optimal may vary depending on the properties of the sludge, etc. In case A3, instead of changing the coagulant injection position, the operating conditions of the decanter 2 may be changed, or both may be changed. Also, changing the coagulant injection position may include changing the flow rate ratio between multiple injection positions.

[0042] For example, in case 4, both the chemical injection amount and chemical injection position are appropriate, so the operating conditions are maintained. However, if the solid concentration is high (e.g., 400 mg / L or higher in Figure 4), the operating conditions of decanter 2 may be changed to reduce the solid concentration. For example, in case 5, there is a possibility that flocculated particles are being destroyed or the chemical injection position is incorrect, so the flow rate of the flocculant controlled by flow rate control unit 85 is reduced and the valves 81A to 81D are switched to change the flocculant injection position. For example, in case 6, there is a possibility that the chemical injection position is maintained and the flow rate of the flocculant controlled by flow rate control unit 85 is reduced. In this case, if the solid concentration is high (e.g., 400 mg / L or higher in Figure 4), the operating conditions of decanter 2 may be changed. The control unit 9 will make a second assessment after a time (e.g., one hour) when the change in conditions has had an effect, and if there is no improvement, further measures will be taken.

[0043] As described above, monitoring the separated liquid and setting appropriate chemical feeding conditions leads to the achievement of a desirable moisture content (e.g., a moisture content of 60 to 80%) for the dehydrated cake, which is the solid content. Other operating conditions of the decanter 2 may be further adjusted to achieve a more optimal moisture content. Examples of operating conditions of the decanter 2 include the centrifugal force set by the rotation speed of the bowl 5, the differential speed between the bowl 5 and the screw conveyor 6, the torque value of the screw conveyor 6, and the supply flow rate of the sludge (the treated liquid). Other conditions may also be used. Furthermore, both the amount and color of the foam may be monitored. For example, a high amount of foam and dark colored foam may indicate a poor reaction state, while a large diameter of the flocculant particles and dark colored foam may indicate the possibility of excessive flocculant addition. Furthermore, the solid concentration of the separated liquid may be determined from image data from the monitoring cameras 44A and 44B.

[0044] In addition to the above-described adjustments to the chemical injection conditions, the control unit 9 may also determine and execute adjustments to the operating conditions of the decanter 2. FIG. 8 is one example. As shown in FIG. 8, cases B1 to B3 are cases in which no solids are present in the image data from the monitoring cameras 44A and 44B, or the solids are so small that they can be considered to be absent. Among cases B1 to B3, case B1 is a case in which the amount of foam is determined to be small based on the image data from the monitoring cameras 46A and 46B, case B2 is a case in which the amount of foam is determined to be appropriate, and case B3 is a case in which the amount of foam is determined to be large. In cases B1 to B3, in which no solids are present in the separated liquid, or are so small that they can be considered to be absent, the chemical injection conditions and decanter operating conditions are determined to be appropriate and are maintained.

[0045] 8 are cases in which it was determined that solids remained in the separated liquid based on image data from the monitoring cameras 44A and 44B. Of these, cases B4 to B6 are cases in which it was determined that the aggregate particle diameter of the solids was small. Cases B4 to B6 are further divided into case B4 in which it was determined that the amount of foam was small based on image data from the monitoring cameras 46A and 46B, case B5 in which it was determined that the amount of foam was appropriate, and case B6 in which it was determined that the amount of foam was large.

[0046] For example, in case B4, it is determined that the amount of chemical injection is insufficient, and measures are taken to increase the flow rate of the coagulant controlled by the flow rate control unit 85. For example, in case B5, it is determined that the amount of chemical injection is slightly insufficient and the coagulation reaction is sufficient, and the flow rate of the coagulant controlled by the flow rate control unit 85 is slightly increased and the coagulant addition position is changed, for example, closer. For example, in case B6, it is determined that the coagulation reaction is insufficient, and the coagulant addition position is changed, for example, farther away.

[0047] Cases B7 to B9 are cases in which the agglomerated particle diameter of the solid content is determined to be appropriate. Cases B7 to B9 are further divided into case B7 in which the amount of foam is determined to be small based on image data from monitoring cameras 46A and 46B, case B8 in which the amount of foam is determined to be appropriate, and case B9 in which the amount of foam is determined to be large.

[0048] Cases B7 to B9 are determined to be caused by the operating conditions of decanter 2 rather than the chemical feeding conditions, and are addressed by changing the operating conditions of decanter 2. For example, in cases B7 and B8, the operating conditions of decanter 2 are changed by, for example, increasing the differential speed between bowl 5 and screw conveyor 6. For example, in case B9, the operating conditions of decanter 2 are changed by, for example, increasing the differential speed between bowl 5 and screw conveyor 6, while it is determined that the chemical feeding amount can be reduced. If the chemical feeding amount can be reduced, operating costs can be reduced.

[0049] Cases B10 to B12 are cases in which the aggregate particle diameter of the solid content is determined to be large. Cases B10 to B12 are further divided into case B10 in which the amount of foam is determined to be small based on image data from monitoring cameras 46A and 46B, case B11 in which the amount of foam is determined to be appropriate, and case B12 in which the amount of foam is determined to be large.

[0050] Cases B10 to B12 are also determined to be caused by the operating conditions of decanter 2 rather than the chemical feeding conditions, and are addressed by changing the operating conditions of decanter 2. For example, in cases B10 and B11, the operating conditions of decanter 2 are changed, such as by increasing the differential speed between bowl 5 and screw conveyor 6. For example, in case B12, the operating conditions of decanter 2 are changed, such as by increasing the differential speed between bowl 5 and screw conveyor 6, while it is determined that the chemical feeding amount can be reduced.

[0051] [Second embodiment] Next, the separated liquid monitoring device 4 of the decanter 2 according to the second embodiment will be described in detail with reference to Figure 9. In the separated liquid monitoring device 4 of this embodiment, one of the two sets of monitoring lines in the first embodiment (Figure 3) is used as a line for a monitoring unit 40 that monitors the state of the separated liquid flowing in the flow path 21a, and the other is used as a line for a monitoring unit 42 that monitors the state of the separated liquid discharged into the liquid receiving box 41.

[0052] The line for the monitoring unit 40 is provided with a diaphragm pump 48, a sight glass 43B, a monitoring camera 44B, and a back-pressure valve 49. The diaphragm pump 48 sends the separation liquid toward the sight glass 43B. The sight glass 43B is vertically oriented so that the separation liquid flows vertically from bottom to top. The back-pressure valve 49 is located downstream of the sight glass 43B. Flexible piping materials or joints, such as hose 21b, are preferably provided in the flow path from the valve 45B to the suction port of the diaphragm pump 48 and in the flow path from the discharge port of the diaphragm pump 48 to the sight glass 43B. Similarly, flexible piping materials or joints, such as hose 21b, are preferably provided in the flow path from the sight glass 43B to the back-pressure valve 49 and in the flow path from the back-pressure valve 49 to the liquid receiving box 41.

[0053] The diaphragm pump 48 sends the separated liquid toward the sight glass 43B. That is, the separated liquid is sampled quantitatively and sent to the sight glass 43B. The flow rate of the separated liquid flowing through the sight glass 43B is set to, for example, 50 to 500 L / h. The diaphragm pump 48 is an example of a pump preferable for sampling the separated liquid monitored by the monitoring unit 40. However, there is no restriction on using a pump other than a diaphragm pump as long as it is a positive displacement reciprocating pump. Examples of other pumps include a plunger pump and a piston pump. A positive displacement reciprocating pump is designed to easily generate pulsation in the discharged fluid. For this reason, a back pressure valve 49 is often provided on the discharge side to suppress pulsation.

[0054] In the above configuration, the separated liquid flowing quantitatively through the sight glass 43B is imaged by the monitoring camera 44B, and image data of the solid content in the separated liquid is obtained. In this embodiment, a positive displacement reciprocating pump is used, and the sight glass 43B is positioned between the pump 48 and the back pressure valve 49, thereby utilizing the pulsating action to facilitate acquisition of image data of the solid content remaining in the separated liquid. In other words, by applying pulsation to the separated liquid flowing through the sight glass 43B, image data can be acquired that shows the solid content dispersed evenly throughout the liquid without breaking down the agglomerated particles. This enables the control unit 9 to determine with increased accuracy the presence or absence of solid content remaining in the separated liquid and the size of the agglomerated particles.

[0055] Actual testing has confirmed that stable determination results can be obtained by placing sight glass 43B between diaphragm pump 48 and back pressure valve 49, and by placing sight glass 43B vertically so that the separated liquid flows from bottom to top. Quantitative sampling using diaphragm pump 48 has the advantage of being less susceptible to disturbances such as changes in the processing flow rate of decanter 2. Furthermore, it has also been confirmed that it is preferable to provide an elbow 21c at the end of the piping on the secondary side (liquid discharge side) of sight glass 43B, bend the flow path 90 degrees, and then connect back pressure valve 49 via hose 21b.

[0056] Meanwhile, the line for the monitoring unit 42, which in the first embodiment (FIG. 3) was provided with a sight glass 43A and a monitoring camera 44A, is omitted in this embodiment, and a flow path is directly connected from the valve 45A to the liquid receiving box 41. Then, as in the first embodiment, an image of bubbles on the surface of the separation liquid in the liquid receiving box 41 is taken using a monitoring camera 46A.

[0057] Image data of the solid content in the separated liquid acquired by the monitoring camera 44B and image data of bubbles in the separated liquid acquired by the monitoring camera 46A are used for determination by the control unit 9. Details are the same as in the first embodiment.

[0058] [Third embodiment] Next, with reference to FIG. 10 , a separated liquid monitoring device 4 for a decanter 2 according to a third embodiment will be described in detail. The separated liquid monitoring device 4 of this embodiment determines chemical dosing conditions and the like according to the flow shown in FIG. 10 . The first and second embodiments described above are not particularly limited, but for convenience of explanation, we have used an example in which determination is made in the order of the presence or absence of solids, etc., and then the amount of foam. In this embodiment, as shown in FIG. 10 , the amount of foam in the separated liquid is first determined. The determination of the amount of foam is based on the area of ​​the foam in the acquired separated liquid image data, as in the first embodiment. The determination result is, for example, "low (including none)," "medium," or "high." For example, the determination of whether the amount of foam is "low (including none)," "medium," or "high" is made by pre-setting ranges for the area of ​​foam for each of "low (including none)," "medium," and "high," and determining which range the area of ​​the foam in the acquired separated liquid image data falls within.

[0059] The separated liquid monitoring device 4 may be configured to output the numerical value of the bubble area in the acquired separated liquid image data. The numerical value of the bubble area is preferably a value calculated by continuously acquiring separated liquid image data and taking a moving average. In other words, information on the amount of foam is output from the output unit of the separated liquid monitoring device 4. The output information on the amount of foam is displayed on a monitor screen so that it can be confirmed by an operator, for example. In this way, the separated liquid monitoring device 4 can also be used to monitor and confirm the current state of chemical injection conditions without making a judgment.

[0060] Furthermore, the separated liquid monitoring device 4 determines the amount of solids in the separated liquid. The determination of the amount of solids is based on image data of the solids in the separated liquid. As an example, image data of the separated liquid associated with the solid concentration is used. That is, as shown in an example in Figure 4, the state of the separated liquid as it appears in the image data varies depending on the solid concentration. Therefore, many pieces of image data of the separated liquid associated with the solid concentration are pre-loaded into a computer such as the control unit 9 for machine learning, and the amount of solids is determined from the image data of the actual separated liquid using this. The determination result is, for example, "low (including none)," "medium," or "high." Alternatively, the value of the solid concentration may be calculated.

[0061] The separated liquid monitoring device 4 may be configured to output the calculated concentration value. The concentration value is preferably a value calculated by continuously acquiring image data of the separated liquid and taking a moving average. In other words, information on the solid concentration is output from the output unit of the separated liquid monitoring device 4. The output information on the solid concentration is displayed on a monitor screen so that it can be confirmed by an operator, for example.

[0062] Furthermore, the separated liquid monitoring device 4 determines the size of agglomerated particles in the solid content. The determination of the size of agglomerated particles in the solid content is based on the size of agglomerated particles in the acquired separated liquid image data, as in the first embodiment. The determination result is, for example, "small," "medium," or "large."

[0063] The separated liquid monitoring device 4 may be configured to output the calculated value of the agglomerated particle diameter. The value of the agglomerated particle diameter is preferably a value calculated by continuously acquiring image data of the separated liquid and taking a moving average. That is, information on the agglomerated particle diameter of the solid content is output from the output unit of the separated liquid monitoring device 4. The output information on the agglomerated particle diameter of the solid content is displayed on a monitor screen so that it can be confirmed by an operator, for example.

[0064] As shown in Figure 10, each judgment result is assigned a corresponding chemical injection condition and / or an adjustment of the operating conditions of the decanter 2, as exemplified in the first and second embodiments described above, and the corresponding control is executed.

[0065] [Fourth embodiment] The chemical supply conditions may be determined taking into consideration costs. As a preferred example, chemical supply conditions that reduce the total cost of sludge treatment are determined based on the amount of bubbles in the separated liquid. As mentioned above, the amount of foam in the separated liquid increases as the concentration of coagulant in the separated liquid increases. Therefore, as shown schematically in Figure 11(a), increasing the chemical dosing rate (= chemical dosing amount / sludge treatment amount x 100) also increases the amount of foam. On the other hand, as shown schematically in Figure 11(a), once the chemical dosing rate reaches a certain level, the moisture content of the dehydrated cake will not decrease any further.

[0066] Furthermore, as mentioned above, the dehydrated cake discharged from the decanter 2 is supplied to the incinerator 37 for incineration. Alternatively, a process other than incineration may be used. The cost of disposing of the dehydrated cake varies depending on the moisture content of the dehydrated cake. However, since the chemical dosing rate and the moisture content have a relationship that reaches a plateau as shown in Figure 11(a), increasing the chemical dosing rate will not result in any further cost reduction, as shown schematically in Figure 11(b). On the other hand, the cost of the flocculant (chemical cost) increases in proportion to the chemical dosing rate, as shown schematically in Figure 11(b).

[0067] Therefore, the total cost of sludge treatment (= dewatered cake disposal cost + chemical cost) roughly takes on a U-shape, as shown schematically in Figure 11(b), and there are chemical dosing conditions that reduce the total cost. Therefore, the control unit 9 with AI functionality determines whether the chemical dosing conditions are set to reduce the total cost based on the amount of foam in the separated liquid. Furthermore, the control unit 9 may control the chemical dosing device 8 and / or the decanter 2 so that the chemical dosing conditions reduce the total cost. As a specific example, the amount of foam corresponding to the chemical dosing conditions that reduce the total cost is preset, for example, as a foam area ratio (see Figure 7), and the foam area ratio of the separated liquid in the acquired image data is controlled to approach the set value.

[0068] The relationship between the amount of foam and the chemical dosing conditions that reduce total costs is confirmed in advance through tests or the like for each type of flocculant and the operating conditions of the decanter 2, and each test data is read into a computer such as the control unit 9 for machine learning. Then, the information on the relationship between the amount of foam and the chemical dosing conditions that reduce total costs is stored in the control unit 9.

[0069] As described above, the decanter 2 of the first to fourth embodiments uses image data of the solids remaining in the separated liquid and image data of bubbles in the separated liquid as criteria for judgment. For example, by analyzing the image data using a computer, it becomes possible to determine the flocculant dosing conditions. As a preferred example, it becomes possible to determine the appropriateness of the flocculant dosing amount and / or the appropriateness of the flocculation reaction state. This contributes to the realization of automatic control of solid separation devices using artificial intelligence (AI), which has been developed in recent years. The solid-liquid separation device is not limited to the decanter 2 and may be other solid-liquid separation devices. Furthermore, the monitoring unit 40 and the monitoring unit 42 may determine the appropriateness of either the flocculant dosing amount or the appropriateness of the flocculation reaction state based on image data acquired by each of them. Furthermore, the judgment may be made based on either image data of the solids remaining in the separated liquid or image data of bubbles in the separated liquid. Furthermore, it is not necessary to use all of the amount of bubbles in the separated liquid, the amount of solids, and the size of the flocculated particles; at least one of these may be used. Furthermore, the separated liquid monitoring device 4 does not need to go so far as to determine the chemical injection conditions, and may simply output any one of the values ​​of the amount of foam, the concentration of solids, and the aggregate particle diameter.

[0070] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various substitutions, modifications, changes, etc. in form and detail can be made therein without departing from the spirit and scope of the invention as defined by the appended claims. [Explanation of symbols]

[0071] 2 decanters 3. Sewage treatment facilities 4 Separated liquid monitoring device 5 bowls 6. Screw conveyor 8 Chemical dosing device 9 Control Unit

Claims

1. a chemical injection device that adds a flocculant to the treatment liquid containing solids; a separation device for performing solid-liquid separation of the treatment liquid; A solid-liquid separation device comprising: a monitoring unit that acquires image data of the separation liquid as it is discharged, released and flowing down from the separation device; and a separation liquid monitoring device including a judgment unit that judges the chemical injection conditions of the flocculant from at least the amount of bubbles in the separation liquid in the image data acquired by the monitoring unit.

2. The solid-liquid separation apparatus according to claim 1, characterized in that the separated liquid monitoring device further comprises a monitoring unit that acquires image data of the solid content remaining in the separated liquid, and determines the chemical injection conditions of the flocculant from at least the amount of bubbles in the separated liquid and the amount of solid content and / or the size of the flocculated particles in the separated liquid.

3. The solid-liquid separator according to claim 1 or 2, characterized in that the judgment result output by the separated liquid monitoring device includes any one of an appropriate chemical injection amount, an excessive chemical injection amount, an insufficient chemical injection amount, and an appropriate chemical injection amount but a poor flocculation reaction state.

4. 2. The solid-liquid separation device according to claim 1, wherein the monitoring unit for acquiring image data of the separated liquid is disposed in a liquid receiving box that discharges the separated liquid, and acquires image data of the separated liquid being discharged into the liquid receiving box.

5. 3. The solid-liquid separator according to claim 2, wherein the monitoring unit that acquires image data of the solid content remaining in the separation liquid acquires the image data of the separation liquid through a transparent member that constitutes a part of the flow path through which the separation liquid flows.

6. the monitoring unit that acquires image data of the solid content remaining in the separated liquid further includes a pump that samples the separated liquid and a back pressure valve provided on the discharge side of the pump; 6. The solid-liquid separator according to claim 5, wherein image data of the separated liquid is acquired through the transparent member between the pump and the back pressure valve.

7. A monitoring unit that acquires image data of a separated liquid that is discharged from a separation device that separates a solid-liquid separation of a treated liquid containing a solid content to which a flocculant has been added, and is released and flowing down; an output unit that analyzes image data acquired by the monitoring unit and outputs information about the amount of bubbles in the separated liquid.

Images