Agitation granulation unit, water treatment apparatus and water treatment method

Abstract

To provide an agitation granulation unit which can inhibit, without interrupting water treatment, coarsened floc from being discharged from the agitation granulation unit.SOLUTION: The agitation granulation unit according to an embodiment comprises an agitation module and a direction switching part. The agitation module performs, by an agitation member, agitation and granulation on treatment target water in an extension installation flow path installed extending from a first extension installation end to a second extension installation end. The direction switching part is configured to: when being in a first operation state, cause the treatment target water to flow from the first extension installation end to the second extension installation end in the extension installation flow path, while causing granulated wastewater to flow downstream from the second extension installation end; and meanwhile, when being in a second operation state, cause the treatment target water to flow from the second extension installation end to the first extension installation end in the extension installation flow path, while causing the granulated wastewater to flow downstream from the first extension installation end.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to an agitation granulation unit, a water treatment device, and a water treatment method. [Background technology]

[0002] In water purification plants, industrial wastewater facilities, power plants, and the like, solid-liquid separation units are used to separate suspended matter such as metal ions, organic matter, and inorganic salts from water to be treated, and the suspended matter is removed from the water to be treated. The solid-liquid separation unit separates suspended matter using, for example, a centrifugal separation technique. In this case, suspended matter (solid matter) contained in the water to be treated is flocculated as a pretreatment for the separation treatment by the solid-liquid separation unit. The water to be treated in which flocs have been formed by the pretreatment is then fed into a centrifuge in the solid-liquid separation unit, and flocs of a predetermined size or larger are separated from the water to be treated by utilizing the centrifugal force of the centrifuge.

[0003] Also, from the viewpoint of preventing the breakup of flocs due to the centrifugal force in the centrifuge, a water treatment device has been developed in which an agitation granulation unit is provided upstream of a solid-liquid separation unit. In such a water treatment device, the agitation granulation unit agitates the water to be treated while adding chemicals including a pH adjuster and multiple types of flocculants to the water to be treated, thereby forming flocs. Then, the solid-liquid separation unit performs the above-mentioned separation process on the granulated wastewater that has been agitated and granulated in the agitation granulation unit. As the agitation granulation unit, for example, a piping-type agitation granulation unit that agitates and granulates the water to be treated inside a pipe is used. By using a piping-type agitation granulation unit as the agitation granulation unit, the overall configuration of the water treatment device can be made compact.

[0004] In a water treatment device equipped with an agitation granulation unit and a solid-liquid separation unit as described above, flocs formed in the water to be treated (chemical-added wastewater) to which chemicals have been added in the agitation granulation unit adhere to the inner wall of the pipe and to the agitation members and the like disposed inside the pipe. When the operation of the water treatment device is continued, the flocs adhering to the inside of the pipe in the agitation granulation unit become coarse, and the coarse flocs may be discharged downstream from the agitation granulation unit because they cannot resist the flow rate of the water to be treated flowing inside the pipe. In a water treatment device, it is required to suppress the discharge of coarse flocs from the agitation granulation unit to the solid-liquid separation unit from the viewpoint of preventing the destruction of flocs during the process in which the granulated wastewater flows into the centrifuge.

[0005] It is possible to peel off and collect flocs that have adhered to the inside of the piping in the agitation granulation unit by flowing water from downstream to upstream, i.e., in the opposite direction to the flow of the water to be treated in the water treatment, while the water treatment is suspended. However, from the viewpoint of ensuring the treatment capacity of the water treatment and from the viewpoint of eliminating the trouble of separately installing equipment for flowing water in the opposite direction, it is required to suppress the discharge of coarse flocs from the agitation granulation unit without interrupting the water treatment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2023-88689 A [Patent Document 2] JP 2017-47368 A [Patent Document 3] JP 2019-34288 A [Patent Document 4] International Publication No. 2018 / 179511 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an agitation granulation unit, a water treatment device, and a water treatment method that can suppress the discharge of coarse flocs from the agitation granulation unit without interrupting water treatment. [Means for solving the problem]

[0008] According to an embodiment, the stirring and granulation unit includes a stirring module and a direction switching unit. The stirring module includes an extension flow path extending from a first extension end to a second extension end, and a stirring member disposed in the extension flow path. In the stirring module, water to be treated to which a chemical has been added flows into the extension flow path, and the water to be treated is stirred and granulated by the stirring member in the extension flow path. The direction switching unit can be switched between a first operating state and a second operating state, and in the first operating state of the direction switching unit, the water to be treated flows from the first extension end to the second extension end in the extension flow path, and the granulated wastewater that has been granulated flows out from the second extension end to the downstream side. In the second operating state of the direction switching unit, the water to be treated flows from the second extension end to the first extension end in the extension flow path, and the granulated wastewater flows out from the first extension end to the downstream side. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a water treatment device according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing an example of the configuration of a solid-liquid separation unit in the water treatment device according to the first embodiment. [Diagram 3] FIG. 3 is a schematic diagram mainly showing the configuration of the granulation region in the agitation granulation unit of the water treatment device according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a flow path through which the water to be treated flows in the granulation region of the agitation granulation unit of the water treatment device according to the first embodiment. [Diagram 5]FIG. 5 is a schematic diagram showing an example of a cross section perpendicular or substantially perpendicular to the axial direction of an agitation module arranged in a granulation region in the agitation granulation unit of the water treatment device according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a flow of the water to be treated in the granulation region in the agitation granulation unit of the water treatment device according to the first embodiment when the direction switching section is in the first operating state. [Figure 7] FIG. 7 is a schematic diagram showing the flow of the water to be treated in the granulation region in the stirring and granulation unit of the water treatment device according to the first embodiment when the direction switching section is in the second operating state. [Figure 8] FIG. 8 is a flowchart illustrating an example of operation control of the direction switching unit performed by the controller in the water treatment device according to the first embodiment. [Figure 9] FIG. 9 is a flowchart that illustrates an example of operational control of a direction switching unit performed by a controller in a water treatment device according to a first modified example. [Figure 10] FIG. 10 is a schematic diagram showing the configuration of a flow path through which the water to be treated flows in the granulation region of an agitation granulation unit of a water treatment device according to a second modified example. [Figure 11] FIG. 11 is a schematic diagram showing an example of a cross section perpendicular or substantially perpendicular to the axial direction of an agitation module disposed in a granulation region in an agitation granulation unit of a water treatment device according to a second modified example. [Figure 12] FIG. 12 is a schematic diagram showing the flow of the water to be treated in the granulation region in the agitation granulation unit of the water treatment device according to the second modified example when the direction switching section is in the first operating state. [Figure 13] FIG. 13 is a schematic diagram showing the flow of the water to be treated in the granulation region in the agitation granulation unit of the water treatment device according to the second modified example when the direction switching section is in the second operating state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments will be described with reference to the drawings.

[0011] (First embodiment) First, as an example of the embodiment, the first embodiment will be described. FIG. 1 shows an example of a water treatment device 1 according to the first embodiment. The water treatment device 1 includes an agitation granulation unit 2, a solid-liquid separation unit 3, and a controller 4. In the water treatment device 1, raw water W0 to be treated water flows into the agitation granulation unit 2, and the water to be treated is agitated and granulated in the agitation granulation unit 2. Then, in the solid-liquid separation unit 3, separation processing is performed on the granulated wastewater (agitated wastewater) W1 flowing in from the agitation granulation unit 2. Therefore, the water treatment device 1 functions as an agitation granulation solid-liquid separation device. In addition, the agitation granulation unit 2 is a piping type agitation granulation unit that agitates and granulates the water to be treated inside the piping 10. Therefore, the water treatment device 1 functions as a piping type agitation granulation solid-liquid separation device.

[0012] The controller 4 constitutes a control device that controls the entire system in which water treatment is performed by the water treatment device 1. The controller 4 includes a processor or integrated circuit, and a storage medium such as a memory. The processor or integrated circuit includes any of a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a microcomputer, an FPGA (Field Programmable Gate Array), and a DSP (Digital Signal processor). The controller 4 may include only one processor or multiple processors. In the controller 4, the processor performs the processing described below. Note that the processing of the controller 4 described below may be performed by a virtual processor in a cloud environment instead of a processor.

[0013] In the water treatment device 1, raw water W0, which is the water to be treated, flows from the upstream side into the inside of the piping 10 of the agitation and granulation unit 2. In one example, a pump (not shown) is disposed upstream of the agitation and granulation unit 2, and the raw water W0 discharged from the pump flows into the inside of the piping 10.

[0014] The agitation granulation unit 2 includes one or more agitation modules 11. In the example shown in FIG. 1, three agitation modules 11 are provided in the agitation granulation unit 2, and the three agitation modules 11 are arranged in series from the upstream side to the downstream side. Each of the agitation modules 11 is formed in a hollow tubular shape, and the three agitation modules 11 are connected in series to form a pipe 10. Each of the agitation modules 11 agitates the water to be treated that has flowed into it from the upstream side. The number of agitation modules 11 is not particularly limited, and may be one or more.

[0015] The stirring and granulation unit 2 includes a chemical additive section 12. The chemical additive section 12 adds one or more types of chemicals to the water to be treated flowing downstream. In one example shown in FIG. 1, four types of chemicals α1 to α4 are added to the water to be treated in the order of chemicals α1, α2, α3, and α4 from the upstream side. Chemical α1 is added to the water to be treated on the upstream side with respect to the upstream end of the pipe 10, and chemical α2 is added to the water to be treated at the upstream end of the most upstream stirring module 11. Chemical α3 is added to the water to be treated at the connection between the most upstream stirring module 11 and the second most downstream (second most upstream) stirring module 11 (11B), and chemical α4 is added to the water to be treated at the connection between the second most downstream stirring module 11 (11B) and the most downstream stirring module 11 (11A).

[0016] In addition, in the example of FIG. 1, a pH adjuster, an inorganic flocculant, a cationic polymer flocculant, and an anionic polymer flocculant are used as the chemicals α1, α2, α3, and α4, respectively, and a pH adjuster and three types of flocculants are added. However, in the stirring and granulation unit 2, the type and number of chemicals to be added are not particularly limited as long as flocs are appropriately formed in the water to be treated by adding the chemicals and stirring. Therefore, the type and number of chemicals to be added are appropriately determined according to the properties of the water to be treated. In addition, the chemical adding section 12 is provided with pumps 13 equal to the number (number of types) of chemicals to be added, and in the example of FIG. 1, four pumps 13 are provided. Each of the pumps 13 discharges a corresponding one of the chemicals α1 to α4 toward the flow path through which the water to be treated (raw water W0) flows.

[0017] In the example of FIG. 1, the chemicals α1 to α4 are added to the water to be treated as described above. Therefore, in the flow path in the stirring and granulation unit 2 through which the water to be treated flows, the area between the position where the chemical α1 is added and the position where the chemical α4 is added is the chemical addition area R1 in which the chemicals α1 to α4 are added to the water to be treated. In the example of FIG. 1, the two upstream of the three stirring modules 11 are located in the chemical addition area R1. In addition, in the flow path through which the water to be treated flows in the stirring and granulation unit 2, the downstream side of the position where the chemical α4 is added is the granulation area R2 in which granulation is performed on the water to be treated. In the example of FIG. 1, the stirring module 11A, which is the most downstream one of the three stirring modules 11, is located in the granulation area R2. Chemical-added wastewater W2, which is the water to be treated to which the chemicals α1 to α4 have been added, flows from the upstream side into the stirring module 11A located in the granulation area R2.

[0018] Each of the agitation modules 11 includes a plurality of agitation members 15. Inside each of the agitation modules 11, the plurality of agitation members 15 are arranged overlapping one another in a direction intersecting the direction in which the water to be treated flows, and are bundled together. Therefore, in each of the agitation modules 11, the plurality of agitation members 15 are bundled together in parallel in the tubular hollow portion.

[0019] Each of the multiple stirring members 15 includes a tubular member 16 and an element 17. In each of the stirring members 15, a flow path is formed inside the tubular member 16, and an element 17 is disposed in the flow path of the tubular member 16. In each of the stirring members 15, the element 17 is fixed to the tubular member 16 and extends in a spiral shape centered on the central axis of the tubular member 16 in the flow path of the tubular member 16. Inside each of the stirring modules 11, in the portion where the multiple stirring members 15 (multiple tubular members 16) are bundled in parallel with each other, the water to be treated flows through the flow path formed by each tubular member 16 of the stirring members 15.

[0020] Each of the stirring members 15 functions as a so-called line mixer (static mixer) through cooperation between the tubular member 16 and the elements 17, and functions as a static mixer without a driven part. Therefore, in each of the stirring members 15, when the water to be treated passes through the flow path of the tubular member 16, a swirling flow is generated in the water to be treated by the action of the spirally arranged elements 17, and a strong shear force is applied to the water to be treated. Therefore, in each of the stirring members 15, when the water to be treated flows through the flow path of the tubular member 16, the water to be treated is stirred.

[0021] In each of the agitation modules 11 located in the chemical addition region R1, the agitation members 15 agitate the water to be treated (raw water W0), thereby mixing the water to be treated with chemicals such as a flocculant and a pH adjuster added by the chemical addition unit 12. In the agitation module 11A located in the granulation region R2, the agitation members 15 agitate the wastewater W2 to which chemicals have been added, thereby causing granulation and aggregation in the water to be treated, and forming flocs in the water to be treated. In each of the agitation modules 11, the number of agitation members 15 to be used and the diameter of the tubular members 16 in each of the agitation members 15 are appropriately determined in advance in accordance with the amount of the water to be treated, the properties of the water to be treated, etc.

[0022] Fig. 2 shows an example of the configuration of the solid-liquid separation unit 3. As shown in Figs. 1 and 2, the solid-liquid separation unit 3 includes one or more solid-liquid separation modules 20, and in the example shown in Figs. 1 and 2, a plurality of solid-liquid separation modules 20 are provided in parallel to each other in the solid-liquid separation unit 3. In the example shown in Fig. 2, each of the solid-liquid separation modules 20 is built into a housing 21. Each of the solid-liquid separation modules 20 is capable of performing a separation process on the granulated wastewater W1 flowing in from the agitation and granulation unit 2.

[0023] In the solid-liquid separation unit 3, the suspended matter (solid matter) flocculated in the agitation and granulation unit 2 is removed from the granulated wastewater W1 by a separation process performed in the solid-liquid separation module 20. As a result, the granulated wastewater W1 is separated into clear treated water W3 and sludge W4 other than the treated water W3. In the example shown in Figs. 1 and 2, five solid-liquid separation modules 20 are provided, but the number of solid-liquid separation modules 20 is not particularly limited. The number of solid-liquid separation modules 20 is appropriately determined in advance depending on the treatment amount, properties, etc. of the water to be treated.

[0024] Each of the solid-liquid separation modules 20 includes one or more centrifuges 22. When separation processing is performed in each of the solid-liquid separation modules 20, each of the centrifuges 22 generates centrifugal force on the granulated wastewater (stirred wastewater) W1 containing flocs in the same manner as a so-called liquid cyclone. As a result, in each of the centrifuges 22, the granulated wastewater W1 is separated into clear treated water W3 and sludge W4, which is a liquid mainly composed of flocs, due to the difference in specific gravity between the liquid and the flocs. In the example of FIG. 2, each of the solid-liquid separation modules 20 is provided with a plurality of centrifuges 22, but the number of centrifuges 22 provided in each of the solid-liquid separation modules 20 may be one. The number of centrifuges 22 in each of the solid-liquid separation modules 20 is appropriately determined in advance depending on the amount of treatment, properties, etc. of the water to be treated to be treated.

[0025] 2, a substantially cylindrical shape is formed inside the housing 21 by the centrifuges 22 of the multiple solid-liquid separation modules 20. When separation processing is performed in each of the solid-liquid separation modules 20, each of the centrifuges 22 causes treated water W3 to flow out to the outer periphery side of the housing 21, and causes sludge W4 to flow out to the inner periphery side of the housing 21. In the solid-liquid separation unit 3, a sludge pod 23 is formed inside the housing 21. The sludge W4 flowing out from each of the solid-liquid separation modules 20 is stored in the sludge pod 23.

[0026] In the solid-liquid separation unit 3, a part of the sludge W4 stored in the sludge pod 23 is extracted as blow water W5, and the solid-liquid separation unit 3 discharges the extracted blow water W5. By discharging a part of the sludge W4 as the blow water W5 in the solid-liquid separation unit 3, the separation efficiency of the granulated wastewater W1 using the centrifuge 22 is improved in each of the solid-liquid separation modules 20. The blow water W5 discharged from the solid-liquid separation unit 3 merges with the raw water W0, which becomes the water to be treated, on the upstream side of the agitation and granulation unit 2.

[0027] 1, the solid-liquid separation unit 3 includes the same number of on-off valves 25 as the solid-liquid separation modules 20, and one on-off valve 25 is provided as an input valve corresponding to each of the solid-liquid separation modules 20. In each solid-liquid separation module 20, the on-off state of the corresponding one of the on-off valves 25 is switched to switch whether or not the granulated wastewater W1 flows in from the stirring and granulation unit 2.

[0028] 1, the solid-liquid separation unit 3 is provided with a flow rate regulating valve 26 serving as a blow water volume regulating valve, and an on-off valve 27 serving as a discharge valve. The amount of blow water W5 flowing out from the solid-liquid separation unit 3 changes as the valve opening degree of the flow rate regulating valve 26 changes. In the solid-liquid separation unit 3, a portion of the sludge W4 that is not extracted as the blow water W5 is discharged from the sludge pod 23 as the on-off valve 27 is opened.

[0029] As shown in FIG. 1 etc., the water treatment device 1 includes a flowmeter 6 and a pressure gauge 7. The flowmeter 6 and the pressure gauge 7 are disposed upstream of the agitation and granulation unit 2. The flowmeter 6 measures the flow rate of the raw water W0 discharged from the pump, i.e., the flow rate of the water to be treated flowing toward the agitation and granulation unit 2 including the agitation module 11A. The pressure gauge 7 measures the water pressure of the water to be treated flowing toward the agitation and granulation unit 2. The flowmeter 6 measures the flow rate and the pressure gauge 7 measures the water pressure periodically. The controller 4 acquires the measurement results of the flowmeter 6 and the pressure gauge 7. For this reason, the controller 4 acquires the time changes of the flow rate and water pressure of the water to be treated (raw water W0) flowing toward the agitation and granulation unit 2.

[0030] The water treatment device 1 also includes a detector (inspector) 8. The detector 8 detects the water quality of the treated water W3 separated from the granulated wastewater W1 by the separation process as described above. That is, the detector 8 is disposed downstream of the solid-liquid separation unit 3 and detects the water quality of the treated water W3 flowing out from the solid-liquid separation unit 3. The water quality index detected by the detector 8 is appropriately determined in accordance with the type and properties of the raw water W0 to be treated. The detector 8 detects, as water quality indexes, one or more of the following, for example, suspended solids (SS (suspended solids) amount), turbidity, floc amount, floc particle size, metal ion concentration, and pH, although the water quality indexes are not limited to these. The detector 8 periodically detects the water quality of the treated water W3.

[0031] The controller 4 acquires the detection results of the detector 8 for the treated water W3. The controller 4 then calculates the change over time in the water quality of the treated water W3 based on the detection results of the detector 8. In one example, the detector 8 is equipped with a camera that captures images of the treated water W3 flowing out from the solid-liquid separation unit 3. In this case, the controller 4 acquires the image of the treated water W3 captured by the camera. The controller 4 then calculates the water quality index of the treated water W3 by AI-analyzing the image of the treated water W3 in real time using data accumulated in a database, etc.

[0032] In the example of FIG. 1, a measuring instrument 5 is disposed between the stirring and granulation unit 2 and the solid-liquid separation unit 3. The measuring instrument 5 measures the particle size of flocs contained in the granulated wastewater W1. The measuring instrument 5 acquires an image of the granulated wastewater W1 by taking a picture with a camera or the like. Then, the image of the granulated wastewater W1 is analyzed or the like to calculate the particle size of the flocs shown in the image. The measuring instrument 5 periodically measures the particle size of the flocs contained in the granulated wastewater W1. The controller 4 acquires the measurement result of the measuring instrument 5 regarding the particle size of the flocs contained in the granulated wastewater W1. Then, the controller 4 calculates the time change in the state of the flocs contained in the granulated wastewater W1 based on the measurement result of the measuring instrument 5.

[0033] As shown in Fig. 1, in addition to the most downstream agitation module 11A, a direction switching unit 30 is provided in the granulation region R2 of the agitation granulation unit 2. In the example of Fig. 1, the direction switching unit 30 is disposed at a connection portion between the second most downstream agitation module 11B and the most downstream agitation module 11A. In the water treatment device 1, the controller 4 controls the operation of the direction switching unit 30.

[0034] FIG. 3 is a schematic diagram of the agitation granulation unit 2, mainly showing the configuration of the granulation region R2, and FIG. 4 is a schematic diagram of the agitation granulation unit 2, mainly showing the configuration of the flow path through which the water to be treated flows in the granulation region R2. As shown in FIG. 3, the agitation module 11A has a central axis C that is coaxial or approximately coaxial with the central axis of the pipe 10, and the axial direction along the central axis C is defined in the agitation module 11A. The central axis C is coaxial or approximately coaxial with the central axis of the pipe 10. In the agitation module 11A, the side on which the agitation module 11B is located in the axial direction is defined as the base end side (arrow A1 side), and the side opposite the base end side in the axial direction is defined as the tip side (arrow A2 side).

[0035] 3 and 4, an extended flow path 31 and a relay flow path 32 are formed inside the agitation module 11A. In the flow path through which the water to be treated (chemical-added wastewater W2) flows, the relay flow path 32 is located downstream of the extended flow path 31, and relays between the extended flow path 31 and the outside of the agitation module 11A (the outside of the agitation granulation unit 2) by the relay flow path 32. In addition, in the flow path through which the water to be treated flows, the flow path inside the agitation module 11B is located upstream of the extended flow path 31.

[0036] The extended flow passage 31 has extended ends E1 and E2, and is extended from the extended end (first extended end) E1 to the extended end (second extended end) E2. In the extended flow passage 31, a turn-back portion 33 where the extended flow passage 31 is turned back is formed between the extended ends E1 and E2. The extended flow passage 31 has an extended region (first extended region) 35 between the extended end E1 and the turn-back portion 33, and an extended region (second extended region) 36 between the extended end E2 and the turn-back portion 33. In the extended region 35, the extended flow passage 31 is extended from the extended end E1 to the turn-back portion 33 toward the tip side of the mixing module 11A. In the extended region 36, the extended flow passage 31 is extended from the turn-back portion 33 to the extended end E2 toward the base end side of the mixing module 11A.

[0037] A bundle of members 37, in which the above-mentioned multiple stirring members 15 are bundled, is disposed in the extended flow passage 31. In this embodiment, the bundle of members 37A is disposed in the extended region 35 between the extended end E1 and the folded back portion 33, and the bundle of members 37B is disposed in the extended region 36 between the extended end E2 and the folded back portion 33. Therefore, in the extended flow passage 31, the bundle of members 37 is disposed in both the extended regions 35 and 36, and the stirring members 15 are disposed therein. Inside the stirring module 11A, the relay flow passage 32 is extended along the axial direction of the stirring module 11A.

[0038] Fig. 5 is a schematic diagram showing an example of a cross section perpendicular or substantially perpendicular to the axial direction of the agitation module 11A arranged in the granulation region R2. Fig. 5 shows a cross section passing through a position away from the base end side of the agitation module 11A with respect to the turn-back portion 33 of the extension flow path 31. As shown in Fig. 5, in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the tubular hollow portion is partitioned by a partition wall 38 into three areas: the extension regions 35, 36 and the relay flow path 32.

[0039] In one example of FIG. 5, in a cross section of the stirring module 11A perpendicular or substantially perpendicular to the axial direction, the area occupied by the extension region 35 is the same or substantially the same as the area occupied by the extension region 36. In a cross section of the stirring module 11A perpendicular or substantially perpendicular to the axial direction, the area occupied by the relay flow path 32 is smaller than the areas occupied by the extension regions 35 and 36. In the cross section shown in FIG. 5, the entire or substantially the entire area occupied by the extension region 35 is occupied by the component bundle 37A, and the entire or substantially the entire area occupied by the extension region 36 is occupied by the component bundle 37B. For this reason, in one example of FIG. 5, in a cross section of the stirring module 11A perpendicular or substantially perpendicular to the axial direction, the area occupied by the component bundle 37A is the same or substantially the same as the area occupied by the component bundle 37B.

[0040] 3 and 4, in the extension region 35, the bundle of members 37A is arranged over a dimension L1 in the axial direction of the agitation module 11A, and in the extension region 36, the bundle of members 37B is arranged over a dimension L2 in the axial direction of the agitation module 11A. In one example of FIGS. 3 and 4, the dimension L2 is the same or approximately the same as the dimension L1.

[0041] In addition, the areas occupied by the extension regions 35, 36 and the relay flow path 32 in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the number of agitation members 15 arranged in each of the extension regions 35, 36, and the aforementioned dimensions L1, L2, etc. are not limited to the above-mentioned examples. The areas occupied by the extension regions 35, 36 and the relay flow path 32 in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the number of agitation members 15 arranged in each of the extension regions 35, 36, and the aforementioned dimensions L1, L2, etc. are appropriately determined in accordance with the properties and treatment amount of the water to be treated, the reaction time required for granulation, and the installation space, etc.

[0042] 3 and 4, the direction switching unit 30 includes two valves 41 and 42. Each of the valves 41 and 42 is a three-way valve. The valve (first valve) 41 has three ports Pa1 to Pa3, and the valve (second valve) 42 has three ports Pb1 to Pb3. In the direction switching unit 30, the valve 41 switches the communication state of the extended end E1 of the extended flow passage 31, and the valve 42 switches the communication state of the extended end E2 of the extended flow passage 31.

[0043] In the valve 41, the upstream flow path, i.e., the flow path inside the mixing module 11B, is connected to the port Pa1, and the extended end (first extended end) E1 of the extended flow path 31 is connected to the port Pa2. In the valve 41, the downstream flow path, i.e., the relay flow path 32 is connected to the port Pa3. In the valve 42, the upstream flow path, i.e., the flow path inside the mixing module 11B, is connected to the port Pb1, and the extended end (second extended end) E2 of the extended flow path 31 is connected to the port Pb2. In the valve 42, the downstream flow path, i.e., the relay flow path 32 is connected to the port Pb3.

[0044] The direction switching unit 30 can be switched between a first operating state and a second operating state by the operation being controlled by the controller 4. FIG. 6 shows a schematic diagram of the flow of the water to be treated in the granulation region R2 in the first operating state of the direction switching unit 30 for the agitation and granulation unit 2. FIG. 7 shows a schematic diagram of the flow of the water to be treated in the granulation region R2 in the second operating state of the direction switching unit 30 for the agitation and granulation unit 2. In FIG. 4, FIG. 6, and FIG. 7, the open ports of the ports Pa1 to Pa3 of the valve 41 and the ports Pb1 to Pb3 of the valve 42 are shown in black, and the closed ports are shown in white.

[0045] As shown in FIG. 3, FIG. 4, FIG. 6, etc., in the first operating state of the direction switching unit 30, in the valve 41, the ports Pa1 and Pa2 are opened and the port Pa3 is closed. Therefore, in the valve 41, the extension end E1 of the extension flow passage 31 communicates with the upstream flow passage, i.e., the flow passage inside the mixing module 11B. Also, in the first operating state of the direction switching unit 30, in the valve 42, the ports Pb2 and Pb3 are opened and the port Pb1 is closed. Therefore, in the valve 42, the extension end E2 of the extension flow passage 31 communicates with the downstream flow passage, i.e., the relay flow passage 32.

[0046] Since the communication state of each of the valves 41 and 42 is as described above, in the first operating state of the direction switching unit 30, the water to be treated (chemical-added wastewater W2) flows from the upstream side into the extended flow passage 31 through the extended end E1. Then, in the extended flow passage 31, the water to be treated flows from the extended end E1 to the extended end E2. That is, in the extended flow passage 31, the water to be treated passes through the extended region 35 (member bundle 37A), the turning back portion 33, and the extended region 36 (member bundle 37B) in this order. Then, the granulated wastewater W1 granulated in the extended flow passage 31 flows out from the extended end E2 to the downstream side. The granulated wastewater W1 flowing out from the extended end E2 flows into the solid-liquid separation unit 3 through the relay flow passage 32. The flow of the water to be treated in the first operating state of the direction switching unit 30 is indicated by the arrow B1 in FIG. 3 and the arrow F1 in FIG. 6.

[0047] 3 and 7, in the second operating state of the direction switching unit 30, in the valve 41, the ports Pa2 and Pa3 are opened and the port Pa1 is closed. Therefore, in the valve 41, the extension end E1 of the extension flow passage 31 communicates with the downstream flow passage, i.e., the relay flow passage 32. Also, in the second operating state of the direction switching unit 30, in the valve 42, the ports Pb1 and Pb2 are opened and the port Pb3 is closed. Therefore, in the valve 42, the extension end E2 of the extension flow passage 31 communicates with the upstream flow passage, i.e., the flow passage inside the mixing module 11B.

[0048] Since the communication state of each of the valves 41 and 42 is as described above, in the second operating state of the direction switching unit 30, the water to be treated (chemical-added wastewater W2) flows from the upstream side into the extended flow passage 31 through the extended end E2. Then, in the extended flow passage 31, the water to be treated flows from the extended end E2 to the extended end E1. That is, in the extended flow passage 31, the water to be treated passes through the extended region 36 (member bundle 37B), the turning back portion 33, and the extended region 35 (member bundle 37A) in this order, and flows in the opposite direction to the flow direction in the first operating state of the direction switching unit 30. Then, the granulated wastewater W1 that has been granulated in the extended flow passage 31 flows out from the extended end E1 to the downstream side. The granulated wastewater W1 that flows out from the extended end E1 flows into the solid-liquid separation unit 3 through the relay flow passage 32. The flow of the water to be treated in the first operating state of the direction switching unit 30 is indicated by arrow B2 in FIG. 3 and arrow F2 in FIG.

[0049] The controller 4 switches the direction switching unit 30 between a first operating state and a second operating state by controlling the operation of the direction switching unit 30. By switching the direction switching unit 30 between the first operating state and the second operating state, the flow direction of the water to be treated in the extended flow path 31 is switched as described above.

[0050] Fig. 8 is a flowchart showing an example of the operation control of the direction switching unit 30 performed by the controller 4. The process of the example of Fig. 8 is repeatedly performed when water treatment of the water to be treated is being performed using the water treatment device 1. The process of the example of Fig. 8 is repeatedly performed when the direction switching unit 30 is in the first operating state and when the direction switching unit 30 is in the second operating state.

[0051] When the process of the example of FIG. 8 is started, the controller 4 calculates the elapsed time from the previous switching of the operation of the direction switching unit 30 (S101). Then, the controller 4 judges whether the calculated elapsed time is longer than a reference time (S102). If the elapsed time is equal to or shorter than the reference time (S102-No), the controller 4 maintains the operating state of the direction switching unit 30 (S103). Therefore, when the direction switching unit 30 is operating in the first operating state, the controller 4 maintains the direction switching unit 30 in the first operating state, and when the direction switching unit 30 is operating in the second operating state, the controller 4 maintains the direction switching unit 30 in the second operating state.

[0052] On the other hand, if the elapsed time is longer than the reference time (S102-Yes), the controller 4 switches the operation state of the direction switching unit 30 (S104). Therefore, when the direction switching unit 30 is operating in the first operation state, the controller 4 switches the direction switching unit 30 to the second operation state, and when the direction switching unit 30 is operating in the second operation state, the controller 4 switches the direction switching unit 30 to the first operation state. As described above, in the example of FIG. 8, the controller 4 switches the operation state of the direction switching unit 30 in response to the elapse of the reference time from the previous switching, and switches the direction in which the treated water flows in the extension flow path 31.

[0053] In the state where water treatment is performed using the water treatment device 1 as described above, flocs formed in the water to be treated (chemical-added wastewater W2) adhere to the inner wall, the stirring member 15, etc. in the extended flow passage 31 located in the granulation region R2 of the agitation and granulation unit 2. In this embodiment, the direction in which the water to be treated flows in the extended flow passage 31 is switched by switching the operation of the direction switching unit 30. Therefore, even if flocs adhere to the inner wall, the stirring member 15, etc. in the extended flow passage 31, the flow direction of the water to be treated is switched in the extended flow passage 31, so that the flocs are peeled off before they become coarse. Therefore, the outflow of coarse flocs from the extended flow passage 31 to the downstream side is suppressed, and the discharge of coarse flocs from the agitation and granulation unit (pipe-type agitation and granulation unit) 2 to the solid-liquid separation unit 3 is suppressed.

[0054] By suppressing the discharge of coarsened flocs into the solid-liquid separation unit 3, it is possible to effectively prevent, for example, flocs larger than the diameter of the inlet to the centrifuge 22 from flowing into the solid-liquid separation unit 3. This effectively prevents the destruction of flocs in the process in which the granulated wastewater W1 flows into the centrifuge 22 in the solid-liquid separation unit 3. Therefore, it is possible to prevent the flocs from being broken down into fine particles in the process in which the granulated wastewater W1 flows into the centrifuge 22, and it is possible to effectively prevent the treated water W3 separated from the granulated wastewater W1 from containing flocs that have been broken down into fine particles upon flowing into the centrifuge 22. This allows the treated water W3 to be maintained at an appropriate water quality.

[0055] In this embodiment, in both a state where the water to be treated flows from the extension end E1 to the extension end E2 and a state where the water to be treated flows from the extension end E2 to the extension end E1, the granulated wastewater W1, which is the water to be treated that has been granulated, flows out downstream from the extension flow path 31. Therefore, regardless of the direction in which the water to be treated flows in the extension flow path 31, the granulated wastewater W1 is discharged from the extension flow path 31 to the solid-liquid separation unit 3. Therefore, flocs attached to the inner wall and the like are peeled off in the extension flow path 31 without interrupting the water treatment. This suppresses the discharge of coarsened flocs from the stirring and granulation unit 2 without interrupting the water treatment.

[0056] Since the water treatment is not interrupted, the water treatment capacity of the water treatment device 1 is appropriately ensured. Furthermore, in this embodiment, flocs attached to the inner wall, etc., of the extended flow path 31 are peeled off without causing the water to flow backward toward the upstream side. This saves the effort and cost of separately providing equipment for causing the water to flow backward toward the upstream side.

[0057] In this embodiment, in both a state where the water to be treated flows from the extension end E1 to the extension end E2 and a state where the water to be treated flows from the extension end E2 to the extension end E1, the water to be treated (chemical-added wastewater W2) passes through the member bundle 37 which is a bundle of the stirring members 15. Therefore, regardless of the direction in which the water to be treated flows in the extension flow path 31, the water to be treated is appropriately stirred by the stirring members 15 in the extension flow path 31, and the water to be treated is appropriately granulated.

[0058] 8, the operating state of the direction switching unit 30 is switched in response to the lapse of a reference time from the previous switching, and the direction in which the water to be treated flows in the extended flow passage 31 is switched periodically. This allows the discharge of coarse flocs from the stirring and granulation unit 2 to be more appropriately suppressed.

[0059] (Modification) In a modified example, the controller 4 controls the operation of the direction switching unit 30 based on one or more of the measurement results from the measuring instrument 5, the measurement results from the flowmeter 6, the measurement results from the pressure gauge 7, and the detection results from the detector 8. FIG. 9 is a flowchart showing an example of the operation control of the direction switching unit 30 performed by the controller 4 in the first modified example. The process of the example of FIG. 9 is repeatedly performed when water treatment of the water to be treated is being performed using the water treatment device 1. The process of the example of FIG. 9 is repeatedly performed when the direction switching unit 30 is in the first operating state and when the direction switching unit 30 is in the second operating state.

[0060] When the process of the example of FIG. 9 is started, the controller 4 acquires the measurement result of the pressure gauge 7, that is, the measurement result of the water pressure of the water to be treated flowing toward the extended flow path 31 (S111). Then, the controller 4 judges whether the measured water pressure of the water to be treated is higher than the reference pressure (S112). If the water pressure is equal to or lower than the reference pressure (S112-No), the controller 4 maintains the operating state of the direction switching unit 30 (S113). On the other hand, if the water pressure is higher than the reference pressure (S112-Yes), the controller 4 switches the operating state of the direction switching unit 30 (S114). Since the process as described above is performed, in this modification, the controller 4 switches the operating state of the direction switching unit 30 in response to the water pressure of the water to be treated flowing toward the extended flow path 31 being higher than the reference pressure, and switches the flow direction of the water to be treated in the extended flow path 31.

[0061] Here, when the flocs adhering to the inner wall of the extended flow passage 31 and the like grow to a certain size, the pressure loss in the entire agitation and granulation unit 2 increases, and the water pressure of the water to be treated flowing toward the extended flow passage 31 increases. In this modification, the flow direction of the water to be treated in the extended flow passage 31 is switched in response to the water pressure measured by the pressure gauge 7 being higher than the reference pressure, so that the flow direction in the extended flow passage 31 is switched before the flocs adhering to the inner wall of the extended flow passage 31 and the like grow coarse. Therefore, the discharge of coarse flocs from the agitation and granulation unit 2 is more appropriately suppressed.

[0062] Furthermore, in one modified example, the controller 4 controls the operation of the direction switching unit 30 based on the measurement result of the flowmeter 6, i.e., the measurement result of the flow rate of the water to be treated flowing toward the extended flow path 31. In this case, the controller 4 switches the operation state of the direction switching unit 30 in response to the flow rate of the water to be treated flowing toward the extended flow path 31 being smaller than the reference flow rate, thereby switching the flow direction of the water to be treated in the extended flow path 31.

[0063] Here, when the flocs adhering to the inner wall of the extension flow passage 31 grow to a certain size, the flow rate of the water to be treated flowing toward the extension flow passage 31 decreases. In this modification, the flow direction of the water to be treated in the extension flow passage 31 is switched in response to the flow rate measured by the flowmeter 6 being smaller than the reference flow rate, so that the flow direction in the extension flow passage 31 is switched before the flocs adhering to the inner wall of the extension flow passage 31 grow coarse. Therefore, the discharge of coarse flocs from the stirring and granulation unit 2 is more appropriately suppressed.

[0064] In a modified example, the controller 4 controls the operation of the direction switching unit 30 based on the measurement result by the measuring device 5, i.e., the measurement result of the particle size of the flocs contained in the granulated wastewater W1. In this case, the controller 4 switches the operation state of the direction switching unit 30 in response to the particle size of the flocs measured by the measuring device 5 being larger than the reference level, and switches the direction in which the water to be treated flows in the extended flow path 31. In one example, the controller 4 determines that the particle size of the flocs is larger than the reference level based on the fact that at least one floc with a particle size larger than the reference particle size is confirmed in the granulated wastewater W1. In another example, the controller 4 determines that the particle size of the flocs is larger than the reference level based on the fact that a predetermined number or more of flocs with a particle size larger than the reference particle size are confirmed in the granulated wastewater W1. In this case, the predetermined number is set to an integer of 2 or more.

[0065] In this modification, the flow direction of the water to be treated is switched in the extended flow path 31 in response to the fact that flocs of a certain size are confirmed in the granulated wastewater W1 discharged from the agitation and granulation unit 2. This effectively prevents flocs of a certain size from being continuously discharged to the solid-liquid separation unit 3. This further appropriately suppresses the discharge of coarse flocs from the agitation and granulation unit 2.

[0066] In a modified example, the controller 4 controls the operation of the direction switching unit 30 based on the detection result by the detector 8, i.e., the detection result regarding the water quality of the treated water W3. In this case, the controller 4 switches the operation state of the direction switching unit 30 in response to the water quality detected by the detector 8 being out of the standard range, and switches the direction in which the water to be treated flows in the extended flow path 31. In one example, the amount of suspended matter or turbidity is detected as a water quality index of the treated water W3. Then, the controller 4 determines that the water quality of the treated water W3 is out of the standard range based on the amount of suspended matter or turbidity in the treated water W3 being greater than a standard value.

[0067] Here, when flocs are broken down during the process in which the granulated wastewater W1 flows into the centrifuge 22, and the flocs that have been refined by the flow into the centrifuge 22 are contained in the treated water W3, the water quality of the treated water W3 may deviate from the standard range. In this modification, the flow direction of the water to be treated in the extended flow path 31 is switched in response to the water quality of the treated water W3 from the solid-liquid separation unit 3 being deviated from the standard range. This effectively prevents flocs that are large enough to be broken by the flow into the centrifuge 22 from being continuously discharged to the solid-liquid separation unit 3. This further appropriately suppresses the discharge of coarse flocs from the stirring and granulation unit 2.

[0068] Furthermore, in controlling the operation of direction switching unit 30, controller 4 may make more than one of the above-mentioned five determinations, which are a determination based on the time elapsed since the previous switching, a determination based on the measurement result by measuring instrument 5, a determination based on the measurement result by flowmeter 6, a determination based on the measurement result by pressure gauge 7, and a determination based on the detection result by detector 8. In one modified example, in controlling the operation of direction switching unit 30, controller 4 makes a determination based on the time elapsed since the previous switching, a determination based on the measurement result by measuring instrument 5, and a determination based on the measurement result by pressure gauge 7.

[0069] In this modification, when a reference time has elapsed since the previous switching, when the particle size of flocs measured by the measuring instrument 5 is greater than the reference level, and when the water pressure measured by the pressure gauge 7 is greater than the reference pressure, the controller 4 switches the operating state of the direction switching unit 30 and switches the direction in which the water to be treated flows in the extended flow path 31. On the other hand, when the reference time has not elapsed since the previous switching, when the measured particle size of flocs falls within the reference level, and when the measured water pressure is equal to or lower than the reference pressure, the controller 4 maintains the operating state of the direction switching unit 30.

[0070] Fig. 10 shows a schematic configuration of the flow path through which the water to be treated flows in the granulation region R2 of the stirring and granulation unit 2 according to the second modification. As shown in Fig. 10, in this modification, an extension flow path 31 and a relay flow path 32 are formed inside the stirring module 11A located in the granulation region R2. The extension flow path 31 extends from an extension end (first extension end) E1 to an extension end (second extension end) E2, and a turn-back portion 33 at which the extension flow path 31 turns back is formed between the extension ends E1 and E2.

[0071] However, in this modification, a member bundle 37 in which a plurality of stirring members 15 are bundled is disposed only in an extended region (first extended region) 35 between the extended end E1 and the folded back portion 33, and is not disposed in an extended region (second extended region) 36 between the extended end E2 and the folded back portion 33. That is, in the extended flow passage 31, the stirring members 15 are disposed only between the extended end E1 and the folded back portion 33, and are not disposed between the extended end E2 and the folded back portion 33.

[0072] Fig. 11 is a schematic diagram showing an example of a cross section perpendicular or substantially perpendicular to the axial direction in the agitation module 11A arranged in the granulation region R2 in this modified example. Fig. 11 shows a cross section passing through a position away from the base end side of the agitation module 11A with respect to the turn-back portion 33 of the extension flow path 31. As shown in Fig. 11, in this modified example as well, in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the tubular hollow portion is partitioned by a partition wall 38 into three areas: the extension regions 35, 36 and the relay flow path 32.

[0073] However, in this modified example, the bundle of components 37 is not arranged in the extended region 36. Therefore, in a cross section of the stirring module 11A perpendicular or substantially perpendicular to the axial direction, the areas occupied by the extended region 36 and the relay flow path 32 are smaller than the area occupied by the extended region 35. Also, in the cross section shown in FIG. 11, the entire or substantially the entire area occupied by the extended region 35 is occupied by the bundle of components 37. Therefore, in the example of FIG. 11, in a cross section of the stirring module 11A perpendicular or substantially perpendicular to the axial direction, the area occupied by the extended region 36 is smaller than the area occupied by the bundle of components 37 in the extended region 35.

[0074] 10 and the like, in the extension region 35, the bundle of members 37 is arranged over a dimension L0 in the axial direction of the mixing module 11A. In this modification, the bundle of members 37 is not arranged in the extension region 36. For this reason, from the viewpoint of ensuring the mixing performance and granulation performance in the extension flow passage 31, it is necessary to make the dimension L0 along the axial direction of the range in which the bundle of members 37 is arranged in the extension region 35 somewhat large. For example, the dimension L0 is larger than the dimensions L1 and L2 in the embodiment of FIG. 3 and FIG. 4 and the like, and in one example, is about twice the dimensions L1 and L2.

[0075] The areas occupied by the extension regions 35, 36 and the relay flow path 32 in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the number of agitation members 15 arranged in the extension region 35, and the aforementioned dimension L0, etc. are not limited to the above-mentioned examples. The areas occupied by the extension regions 35, 36 and the relay flow path 32 in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction, the number of agitation members 15 arranged in the extension region 35, and the aforementioned dimension L0, etc. are appropriately determined in accordance with the properties and treatment amount of the water to be treated, the reaction time required for granulation, the installation space, etc.

[0076] As shown in FIG. 10 and other figures, the direction switching unit 30 also includes two valves 41 and 42 in this modified example. As in the above-described embodiment, the valve 41 switches the communication state of the extension end E1 of the extension flow path 31, and the valve 42 switches the communication state of the extension end E2 of the extension flow path 31. FIG. 12 shows the flow of the water to be treated in the granulation region R2 in the first operating state of the direction switching unit 30 for the stirring and granulation unit 2. FIG. 13 shows the flow of the water to be treated in the granulation region R2 in the second operating state of the direction switching unit 30 for the stirring and granulation unit 2. In FIG. 10, FIG. 12, and FIG. 13, the open ports of the ports Pa1 to Pa3 of the valve 41 and the ports Pb1 to Pb3 of the valve 42 are shown in black, and the closed ports are shown in white.

[0077] As shown in Figs. 10 and 12 etc., in this modified example, in the first operating state of the direction switching unit 30, the water to be treated (chemical-added wastewater W2) flows from the upstream side into the extended flow passage 31 via the extended end (first extended end) E1. Then, in the extended flow passage 31, the water to be treated flows from the extended end E1 to the extended end (second extended end) E2. Then, the granulated wastewater W1 that has been granulated in the extended flow passage 31 flows out downstream from the extended end E2. The flow of the water to be treated in the first operating state of the direction switching unit 30 is indicated by the arrow F3 etc. in Fig. 12.

[0078] As shown in FIG. 13 and other figures, in this modified example, in the second operating state of the direction switching unit 30, the water to be treated (chemical-added wastewater W2) flows from the upstream side into the extended flow passage 31 via the extended end (second extended end) E2. Then, in the extended flow passage 31, the water to be treated flows from the extended end E2 to the extended end (first extended end) E1. That is, the water to be treated flows in the opposite direction to the flow direction in the first operating state of the direction switching unit 30. Then, the granulated wastewater W1 that has been granulated in the extended flow passage 31 flows out from the extended end E1 to the downstream side. The flow of the water to be treated in the first operating state of the direction switching unit 30 is indicated by arrow F4 and other figures in FIG. 13.

[0079] This modification also provides the same functions and effects as the above-described embodiment, etc. That is, this modification also suppresses the discharge of coarse flocs from the stirring and granulation unit 2 without interrupting water treatment.

[0080] In addition, in this modification, since the member bundle 37 is not arranged in the extension region 36 of the extension flow path 31, it is possible to reduce the area occupied by the extension region 36 in the cross section of the agitation module 11A perpendicular or substantially perpendicular to the axial direction. The area occupied by the extension region 36 in the cross section of the agitation module 11A is reduced, so that the dimensions of the agitation module 11A in the radial direction are reduced. Therefore, in this modification shown in FIG. 10 and the like, it is possible to reduce the dimensions of the agitation module 11A in the radial direction compared to the embodiments shown in FIG. 3 and FIG. 4 and the like. That is, by adopting the configuration of this modification shown in FIG. 10 and the like, it is possible to reduce the dimensions of the piping 10 in the radial direction in the granulation region R2 compared to the configuration of the embodiments shown in FIG. 3 and FIG. 4 and the like.

[0081] On the other hand, in the configuration of the embodiment of Figures 3 and 4, etc., the member bundles 37 are arranged in both the extension regions 35, 36, so that each of the above-mentioned dimensions L1 and L2 can be made smaller than the dimension L0 of the modified example of Figure 10, etc. For this reason, by adopting the configuration of the embodiment of Figures 3 and 4, etc., it is possible to reduce the dimension of the mixing module 11A in the axial direction compared to the configuration of the modified example of Figure 10, etc. In other words, by adopting the configuration of the embodiment of Figures 3 and 4, etc., it is possible to reduce the dimension of the pipe 10 in the axial direction in the granulation region R2 compared to the configuration of the modified example of Figure 10, etc.

[0082] As described above, if the number of stirring modules 11 arranged in the granulation region R2 is the same, the size of the granulation region R2 in the radial direction is larger and the size of the granulation region R2 in the axial direction is smaller in the configuration of Figures 3 and 4, etc., than in the configuration of Figure 10, etc. If the number of stirring modules 11 arranged in the granulation region R2 is the same, the size of the granulation region R2 in the axial direction is larger and the size of the granulation region R2 in the radial direction is smaller in the configuration of Figures 10, etc., than in the configuration of Figures 3 and 4, etc. For this reason, it is possible to use the configuration of Figures 3 and 4, etc. and the configuration of Figure 10, etc., depending on the situation of the space in which the stirring and granulation unit 2 is installed, etc.

[0083] According to at least one of these embodiments or examples, in the first operating state of the direction switching unit, the water to be treated flows from the first extension end to the second extension end in the extended flow path, and the granulated wastewater that has been granulated flows out from the second extension end to the downstream side. In the second operating state of the direction switching unit, the water to be treated flows from the second extension end to the first extension end in the extended flow path, and the granulated wastewater flows out from the first extension end to the downstream side. This makes it possible to provide an agitation and granulation unit, a water treatment device, and a water treatment method that can suppress the discharge of coarse flocs from the agitation and granulation unit without interrupting treatment.

[0084] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0085] 1...water treatment device, 2...mixing and granulating unit, 3...solid-liquid separation unit, 4...controller, 5...measuring instrument, 6...flow meter, 7...pressure gauge, 8...detector, 10...piping, 11 (11A, 11B)...mixing module, 12...chemical addition section, 15...mixing member, 30...direction switching section, 31...extended flow path, 33...turn section, 37 (37A, 37B)...component bundle, 41...valve (first valve), 42...valve (second valve), E1...extended end (first extended end), E2...extended end (second extended end), W0...raw water, W1...granulated wastewater (mixed wastewater), W2...chemical-added wastewater, W3...treated water, W4...sludge, W5...blow water, R1...chemical addition area, R2...granulation area.

Claims

1. a mixing module including an extension flow path extending from a first extension end to a second extension end and a mixing member disposed in the extension flow path, in which water to be treated to which a chemical has been added flows into the extension flow path, and the water to be treated is mixed and granulated by the mixing member in the extension flow path; a flow switching unit switchable between a first operating state and a second operating state, in which in the first operating state, the water to be treated flows from the first extension end to the second extension end in the extension flow path, and the granulated wastewater that has been granulated flows out from the second extension end to the downstream side, and in the second operating state, the water to be treated flows from the second extension end to the first extension end in the extension flow path, and the granulated wastewater flows out from the first extension end to the downstream side; The agitation granulation unit comprises:

2. The direction switching unit includes a first valve that switches a communication state of the first extension end of the extension flow path, and a second valve that switches a communication state of the second extension end of the extension flow path, In the first operating state of the direction switching unit, the first extension end is connected to the upstream side by the first valve, and the second extension end is connected to the downstream side by the second valve, In the second operating state of the direction switching unit, the first extension end is connected to the downstream side by the first valve, and the second extension end is connected to the upstream side by the second valve. The agitation granulation unit according to claim 1.

3. In the extension flow path, a folded portion at which the extension flow path is folded is formed between the first extension end and the second extension end, In the extension flow path, the stirring member is disposed both between the first extension end and the turned-back portion and between the second extension end and the turned-back portion. The agitation granulation unit according to claim 1.

4. In the extension flow path, a folded portion at which the extension flow path is folded is formed between the first extension end and the second extension end, In the extension flow path, the stirring member is disposed only between the first extension end and the turn-back portion, and is not disposed between the second extension end and the turn-back portion. The agitation granulation unit according to claim 1.

5. The stirring and granulation unit according to any one of claims 1 to 4, A solid-liquid separation unit that includes a centrifuge and performs a separation process on the granulated wastewater that flows in from the agitation granulation unit using the centrifuge; A controller that controls the operation of the direction switching unit and switches the direction switching unit between the first operating state and the second operating state to switch the direction in which the treated water flows in the extension flow path; A water treatment device comprising:

6. The water treatment device of claim 5 , wherein the controller switches the flow direction of the water to be treated in the extension flow path in response to a reference time having elapsed since a previous switching.

7. Further comprising a pressure gauge for measuring the water pressure of the water to be treated flowing toward the extension flow path of the mixing module, The controller switches the direction in which the water to be treated flows in the extension flow path in response to the water pressure measured by the pressure gauge being higher than a reference pressure. The water treatment device according to claim 5.

8. A measuring device is further provided between the extension flow path of the mixing module and the solid-liquid separation unit to measure the particle size of flocs contained in the granulated wastewater, the controller switches a flow direction of the water to be treated in the extension flow path in response to the particle size of the flocs measured by the measuring device being larger than a reference level. The water treatment device according to claim 5.

9. Further comprising a flow meter for measuring a flow rate of the water to be treated flowing toward the extension flow path of the mixing module, The controller switches the flow direction of the water to be treated in the extension flow path in response to the flow rate measured by the flow meter being smaller than a reference flow rate. The water treatment device according to claim 5.

10. The solid-liquid separation unit further includes a detector for detecting the water quality of the treated water separated from the granulated wastewater by the separation treatment in the solid-liquid separation unit. The controller switches the flow direction of the water to be treated in the extension flow path in response to the water quality detected by the detector being out of the standard range. The water treatment device according to claim 5.

11. The water treatment device of claim 10 , wherein the controller determines that the water quality is outside the reference range based on an amount of suspended matter or turbidity in the treated water being greater than a reference value.

12. The water to be treated, to which a chemical has been added, is introduced into an extension flow path that extends from a first extension end to a second extension end and in which a stirring member is disposed, and the water to be treated is stirred and granulated by the stirring member in the extension flow path. By switching the direction switching unit to a first operating state, the water to be treated is caused to flow from the first extension end to the second extension end in the extension flow path, and the granulated wastewater that has been granulated is caused to flow downstream from the second extension end. By switching the direction switching unit to a second operating state different from the first operating state, the water to be treated is caused to flow from the second extension end to the first extension end in the extension flow path, and the granulated wastewater is caused to flow out from the first extension end to the downstream side. A water treatment method comprising:

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