Precipitation treatment apparatus, precipitation treatment method

Abstract

To provide a sedimentation treatment device, etc., that can improve the settling properties of solids in water to be treated. [Solution] A sedimentation apparatus comprising a first rotating shaft for rotating a discharge unit that discharges water to be treated into a sedimentation tank, and a second rotating shaft for rotating a scraping unit that scrapes up solid matter settled in the sedimentation tank, wherein the rotational speed of the first rotating shaft is smaller than the rotational speed of the second rotating shaft.

Description

Technical Field

[0001] The present invention relates to a precipitation treatment apparatus and a precipitation treatment method.

Background Art

[0002] In the precipitation treatment apparatus described in Patent Document 1, a feed supply pipe is vertically installed inside a sedimentation tank, and a blow-out pipe having a plurality of blow-out holes is provided at the tip of the feed supply pipe. Further, in the precipitation treatment apparatus described in Patent Document 1, a sludge scraping machine is provided below the feed supply pipe. The feed supply pipe and the sludge scraping machine are rotated by the same drive unit. In the precipitation treatment apparatus described in Patent Document 1, the feed formed in the feed supply pipe flows out from the plurality of blow-out holes provided in the blow-out pipe into the sedimentation tank, and the initial flocs in the feed are captured by the aggregated floc layer formed by a uniform upward flow and become coarse flocs. A part of the aggregated floc layer settles to the lower part of the sedimentation tank to become concentrated sludge, and the sludge scraping machine is rotated to further concentrate the sludge to form a concentrated sludge layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to improve the sedimentation performance, it is desirable to reduce the upward flow velocity of the water to be treated generated in the sedimentation space of the sedimentation tank. This is because when the upward flow velocity of the water to be treated is large, it is difficult for solids to settle. In the precipitation treatment apparatus described in Patent Document 1, there was room for improvement in terms of sedimentation performance. In order to sufficiently concentrate and discharge the sludge by rotating the sludge scraping machine, it is necessary to increase the rotation speed of the sludge scraping machine. However, when the rotation speed of the sludge scraping machine is increased, the rotation speed of the blow-out pipe also increases, the flow in the sedimentation space is disturbed, and the upward flow velocity of the water to be treated increases. The present invention aims to provide a sedimentation treatment device, etc., that can improve the settling properties of solids in water to be treated. [Means for solving the problem]

[0005] The present invention, completed with this objective in mind, is a sedimentation apparatus comprising a first rotating shaft for rotating a discharge unit that discharges water to be treated into a sedimentation tank, and a second rotating shaft for rotating a scraping unit that scrapes up solid matter settled in the sedimentation tank, wherein the rotational speed of the first rotating shaft is smaller than the rotational speed of the second rotating shaft. Here, the first rotation axis may be located outside the second rotation axis. Furthermore, the drive source that rotates the first rotating shaft and the drive source that rotates the second rotating shaft may be different. Furthermore, the scraping section may be located below the discharge section and may also include a cleaning section provided above the scraping section, which rotates together with the scraping section to clean the discharge holes formed in the discharge section. Furthermore, the discharge holes are formed in a plurality of locations aligned in the extending direction of the discharge section, and the cleaning section may have a single brush for cleaning the plurality of discharge holes. Furthermore, from another perspective, the present invention is a sedimentation treatment method in which water to be treated is discharged from a discharge section into a sedimentation tank and solid matter settled in the sedimentation tank is scraped up by a scraping section, wherein the rotational speed of the first rotating shaft for rotating the discharge section is made smaller than the rotational speed of the second rotating shaft for rotating the scraping section. In this case, the discharge hole formed in the discharge section may be cleaned by a cleaning section that is fixed to the scraping section and rotates together with the scraping section. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a sedimentation treatment device, etc., that can improve the settling properties of solids in water to be treated. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a schematic configuration of the precipitation treatment apparatus according to the first embodiment. [Figure 2] This figure shows an example of a schematic configuration of a mechanism for rotating the distribution rotation axis. [Figure 3] This figure shows an example of a schematic configuration of the precipitation treatment apparatus according to the second embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings. <First Embodiment> Figure 1 shows an example of a schematic configuration of the precipitation treatment apparatus 1 according to the first embodiment. Figure 2 shows an example of a schematic configuration of the mechanism for rotating the distribution rotation shaft 80. The sedimentation treatment apparatus 1 is used for solid-liquid separation treatment, which separates water to be treated, containing solid matter (in other words, suspended matter), into treated water and solid matter. The water to be treated in the sedimentation treatment apparatus 1 can be any water containing the solid matter to be separated, and the source of the water to be treated and the type of solid matter are not particularly limited. Examples of water to be treated include factory wastewater, domestic wastewater, and river water. Furthermore, the water to be treated may be factory wastewater or domestic wastewater that has been treated using a reaction tank with mechanical aeration (in other words, an oxidation ditch) (in other words, using the OD method).

[0009] The sedimentation treatment apparatus 1 comprises a sedimentation tank 10 for settling solid matter in the water to be treated, a supply member 20 provided cylindrically inside the sedimentation tank 10 for supplying the water to be treated to the sedimentation tank 10, and a supply pipe 30 for supplying the water to be treated from outside the sedimentation tank 10 to the inside of the supply member 20. In the sedimentation treatment apparatus 1, the sludge formed by the settling of solid matter in the water to be treated is concentrated. The sedimentation treatment apparatus 1 also comprises a scraping unit 40 for scraping the concentrated sludge that has settled on the bottom surface of the sedimentation tank 10, and a scraping rotation shaft 50 for rotating the scraping unit 40. Furthermore, the sedimentation treatment apparatus 1 comprises a plurality (for example, 4) of distributors 60 located above the scraping unit 40 and below the supply member 20 for distributing the water to be treated supplied to the inside of the supply member 20 into the sedimentation tank 10. Furthermore, the sedimentation apparatus 1 includes a chamber 70 that holds a plurality of distributors 60 and stores the water to be treated before it is supplied to the distributors 60, and a distribution rotating shaft 80 that rotates the chamber 70. The sedimentation apparatus 1 also includes a cleaning unit 90 that cleans the distributors 60, and a control device 100 that controls the rotational drive of the scraping rotating shaft 50 and the distribution rotating shaft 80.

[0010] The sedimentation tank 10 is for settling solid matter in the water to be treated. The sedimentation tank 10 is cylindrical with a bottom 11. The sedimentation tank 10 is installed so that the direction of its centerline CL is vertical. In the following description, the side with the centerline CL may be referred to as the "inside," and the side away from the centerline CL may be referred to as the "outside." A recess 12 for sludge extraction is formed in the inner part of the bottom 11 (in other words, the central part). An extraction pipe 13 for extracting sludge to the outside of the sedimentation tank 10 is connected to the recess 12, and a pump (not shown) is connected to the extraction pipe 13. By driving the pump, the sludge settled in the recess 12 of the bottom 11 can be extracted to the outside of the sedimentation tank 10 via the extraction pipe 13. All of the upper openings of the sedimentation tank 10 are covered by a top 15. However, the top 15 does not have to cover all of the openings of the sedimentation tank 10, and may cover only a part of the openings.

[0011] The supply member 20 is for supplying water to be treated into the sedimentation tank 10. The supply member 20 is a cylindrical member. The center line of the supply member 20 is located in the center of the sedimentation tank 10 so as to coincide with the center line CL of the sedimentation tank 10. The upper part of the supply member 20 is fixed to the top part 15. An opening 21 is formed in the vertical center of the supply member 20, allowing the inside and outside to pass through. When viewed horizontally, the shape of the opening 21 can be exemplified as being circular. Note that the upper part of the supply member 20 does not necessarily have to be fixed to the top part 15; for example, it may be fixed to a beam spanning the top of the sedimentation tank 10.

[0012] The supply pipe 30 is for supplying water to be treated from outside the sedimentation tank 10 to inside the supply member 20. The inner end of the supply pipe 30 is fixed, for example, by welding around the opening 21 in the supply member 20, and the outer end is exposed to the outside of the sedimentation tank 10. The supply pipe 30 is cylindrical, and its inner diameter is the same as the diameter of the opening 21. It can also be exemplified that the supply pipe 30 is arranged so that the direction of its centerline is horizontal. The supply pipe 30 may be composed of multiple pipes connected together.

[0013] The scraping section 40 is for scraping up sludge accumulated in the sedimentation tank 10. The scraping section 40 has a plurality of scraping members 41 (for example, two or three) for scraping up sludge, and a plurality of support members 42 (for example, four) for supporting the plurality of scraping members 41. The support members 42 are cylindrical tubes, with their inner ends fixed to the scraping rotation shaft 50, for example by welding, and their outer ends extending to the inner circumferential surface 17 of the sedimentation tank 10. The scraping members 41 are fixed to the lower part of the support members 42, for example by welding. The scraping section 40 rotates together with the scraping rotation shaft 50. The support members 42 may also be composed of multiple tubes connected together.

[0014] The scraping rotation shaft 50 is for rotating the scraping section 40. The scraping rotation shaft 50 is positioned vertically such that its centerline CL coincides with the axis of rotation. The upper end of the scraping rotation shaft 50 is connected to a scraping motor 51 fixed to the top section 15, and the lower end extends to a recess 12 in the bottom section 11 of the sedimentation tank 10. The scraping rotation shaft 50 may be hollow or solid. The scraping motor 51 can be exemplified as a motor whose output shaft is positioned perpendicular to the scraping rotation shaft 50. However, the scraping motor 51 may also be a motor whose output shaft is positioned parallel to the scraping rotation shaft 50.

[0015] Chamber 70 holds multiple distributors 60 and stores the water to be treated before it is supplied to the distributors 60. Chamber 70 has a cylindrical portion 71 and a bottom portion 72 provided to cover the lower opening of the cylindrical portion 71. A vertical through hole (not shown) is formed in the center of the bottom portion 72. Chamber 70 is fixed to the distribution rotation shaft 80 by welding, for example, with the distribution rotation shaft 80 passing through the through hole. The outer circumferential surface of the upper end of the cylindrical portion 71 is positioned to face the lower end and inner circumferential surface of the supply member 20. Chamber 70 rotates relative to the supply member 20 together with the distribution rotation shaft 80. At the lower end of the cylindrical portion 71, a horizontal through-hole (not shown) is formed, allowing passage between the inside and the outside. Multiple horizontal through-holes (for example, four) are formed at equal intervals in the circumferential direction. The horizontal through-holes can be exemplified by having a circular shape when viewed horizontally.

[0016] The distributor 60 is for distributing the water to be treated supplied inside the supply member 20 into the sedimentation tank 10. The distributor 60 is a cylindrical pipe, and the inner end is fixed, for example, by welding around the horizontal through-hole in the cylindrical portion 71 of the chamber 70. And the distributor 60 extends outward so that the outer end is located near the inner peripheral surface 17 of the sedimentation tank 10. The plurality of distributors 60 are respectively arranged at positions corresponding to the plurality of horizontal through-holes formed in the chamber 70. It can be exemplified that the inner diameter of the distributor 60 is the same as the diameter of the horizontal through-hole. Also, it can be exemplified that the distributor 60 is arranged so that the direction of the center line is horizontal. Incidentally, the distributor 60 may be constituted by connecting a plurality of pipes. A vertical through-hole 61 is formed in the lower end portion of the distributor 60. A plurality (for example, 20) of through-holes 61 are formed at equal intervals in the horizontal direction.

[0017] The distribution rotating shaft 80 is for rotating the distributor 60. The distribution rotating shaft 80 is arranged vertically so that the center line CL coincides with the rotation axis. The distribution rotating shaft 80 is hollow (in other words, cylindrical). And the distribution rotating shaft 80 is arranged outside the scraping rotating shaft 50. A worm wheel 81 is fitted into the upper end portion of the distribution rotating shaft 80. The worm wheel 81 constitutes a worm gear with a worm 83 fitted into the distribution motor 82. The distribution motor 82 is fixed to the top portion 15 and the output shaft is arranged at a right angle to the distribution rotating shaft 80. The chamber 70 is welded to the lower end portion of the distribution rotating shaft 80. When the distribution motor 82 rotates, the distribution rotating shaft 80 rotates, and when the distribution rotating shaft 80 rotates, the chamber 70 and the distributor 60 rotate.

[0018] The cleaning unit 90 cleans the distributor 60. The cleaning unit 90 is fixed to the support member 42 of the scraping unit 40 and rotates together with the scraping rotation shaft 50. The cleaning unit 90 includes a brush 91 that is disposed to be in contact with a plurality of through-holes 61 formed in the distributor 60 to clean the through-holes 61, and a fixing member 95 that fixes the brush 91 to the support member 42 of the scraping unit 40. The brush 91 has a base 92 that extends in the radial direction of rotation, and bristles 93 that are implanted upward at a constant interval with respect to the base 92. Examples of the material of the base 92 can include metal and synthetic resin. The material of the bristles 93 is metal or synthetic fiber, and a plurality of bristles 93 are bundled and implanted in the base 92. The fixing member 95 is a cylindrical tube. The lower end portion is fixed to the support member 42 of the scraping unit 40, for example, by welding, and the upper end portion is fixed to the base 92 of the brush 91, for example, by welding. Note that the cleaning unit 90 may be provided for each of the plurality of support members 42 of the scraping unit 40, that is, the same number as the support members 42, or may be provided only for any one of the plurality of support members 42.

[0019] The control device 100 controls the rotational drive of the scraping rotation shaft 50 and the distribution rotation shaft 80. The control device 100 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) (not shown) that is a storage area for storing programs, and a RAM (Random Access Memory) (not shown) that is an execution area for programs. The control device 100 controls the driving of the scraping motor 51 and the distribution motor 82 by causing the CPU to execute a program stored in the ROM or a storage device such as an HDD (Hard Disk Drive) or a semiconductor memory.

[0020] In the sedimentation treatment apparatus 1 configured as described above, water to be treated containing solid matter is supplied into the supply member 20 via the supply pipe 30. The water to be treated containing solid matter reaches the distributor 60 via the horizontal through-hole of the chamber 70 and is discharged into the sedimentation tank 10 from the through-hole 61 of the distributor 60. The solid matter settles at the bottom of the sedimentation tank 10, while a clear layer, which is the supernatant, forms at the top of the sedimentation tank 10. The cleared treated water W1 is discharged through the discharge section 16 located at the top of the sedimentation tank 10. At the bottom 11 of the sedimentation tank 10, the sludge formed from the settled solid matter is concentrated and scraped towards the center by the scraping section 40 which rotates around the center line CL. When the pump is driven, the sludge settled in the recess 12 of the bottom 11 is drawn out of the sedimentation tank 10 via the extraction pipe 13.

[0021] In the sedimentation apparatus 1 configured as described above, the rotational speed of the distributor 60 is less than the rotational speed of the scraping section 40. When the scraping motor 51 rotates, the scraping rotating shaft 50 rotates. Since the scraping part 40 is fixed to the scraping rotating shaft 50, when the scraping motor 51 rotates, the scraping part 40 rotates with the center line CL as its axis of rotation. When the distribution motor 82 rotates, the worm 83 fitted into the distribution motor 82 and the worm wheel 81 fitted into the distribution rotation shaft 80 rotate the distribution rotation shaft 80. Since the chamber 70 is fixed to the distribution rotation shaft 80 and the distributor 60 is fixed to the chamber 70, when the distribution motor 82 rotates, the distributor 60 rotates with the center line CL as its axis of rotation.

[0022] The control device 100 then controls the driving of the scraping motor 51 and the distribution motor 82 so that the rotational speed of the distributor 60 is less than the rotational speed of the scraping unit 40. This is for the following reasons. In order to sufficiently concentrate the sludge by rotating the scraping unit 40, the rotation speed of the scraping unit 40 must be set to a predetermined speed or higher. On the other hand, if the rotation speed of the distributor 60 is increased, the flow in the sedimentation space within the sedimentation tank 10 (in other words, the space within the sedimentation tank 10 excluding the supply member 20, distributor 60, and chamber 70) becomes more turbulent, and the upward flow velocity of the treated water increases. When the upward flow velocity increases, it becomes more difficult for solid matter to settle. Therefore, in the sedimentation treatment apparatus 1, the rotation speed of the scraping unit 40 is set to a predetermined speed or higher, while the rotation speed of the distributor 60 is set to a predetermined speed or lower in order to reduce the upward flow velocity of the treated water in the sedimentation space. Furthermore, in order to achieve different rotation speeds for the scraping unit 40 and the distributor 60, the scraping rotation shaft 50 and the distribution rotation shaft 80 are made to be different. Furthermore, the scraping motor 51, which is the drive source for the scraping rotation shaft 50, and the distribution motor 82, which is the drive source for the distribution rotation shaft 80, are different.

[0023] As described above, the sedimentation apparatus 1 includes a distributor 60 (an example of a discharge unit) that extends from the centerline CL side toward the inner circumferential surface 17 side of a cylindrical sedimentation tank 10 having a bottom 11 for settling solids in the water to be treated, and rotates with the centerline CL as its axis of rotation. The distributor 60 discharges the water to be treated into the sedimentation space in the sedimentation tank 10. The sedimentation apparatus 1 also includes a scraping unit 40 that rotates with the centerline CL as its axis of rotation to scrape up the solids settled at the bottom 11. The rotational speed of the distributor 60 is smaller than the rotational speed of the scraping unit 40. With the sedimentation apparatus 1, the upward flow velocity of the water to be treated in the sedimentation tank 10 can be reduced compared to the case where the rotational speed of the distributor 60 is greater than or equal to the rotational speed of the scraping unit 40, thereby improving the settling performance. Therefore, with the sedimentation apparatus 1, it is possible to increase the amount of water to be treated while keeping the size of the sedimentation tank 10 the same.

[0024] The distribution rotation shaft 80 (an example of a first rotation shaft) that rotates the distributor 60 is located outside the scraping rotation shaft 50 (an example of a second rotation shaft) that rotates the scraping section 40. This makes it possible to make the rotation speed of the scraping section 40 and the rotation speed of the distributor 60 different with a simple configuration. In other words, the drive sources for the scraping rotation shaft 50 and the distribution rotation shaft 80 are fixed to the top section 15, and since the distributor 60 is above the scraping section 40, the distribution rotation shaft 80 is located outside the scraping rotation shaft 50, resulting in a simple configuration.

[0025] Furthermore, the distribution motor 82, which is an example of a drive source that rotates the distribution rotation shaft 80, is different from the scraping motor 51, which is an example of a drive source that rotates the scraping rotation shaft 50. This makes it possible to reliably achieve different rotation speeds for the scraping section 40 and the distributor 60.

[0026] Furthermore, the scraping section 40 is located below the distributor 60. The sedimentation apparatus 1 also includes a cleaning section 90, which is located above the scraping section 40 and rotates with the scraping section 40 to clean the through-holes 61 (an example of discharge holes) formed in the distributor 60. Specifically, the cleaning section 90 has a brush 91 positioned to contact the through-holes 61 of the distributor 60, and a fixing member 95 that fixes the brush 91 to the support member 42 of the scraping section 40. The cleaning section 90 rotates with the scraping section 40, which rotates at a different rotational speed than the distributor 60. Therefore, the brush 91 contacts the through-holes 61 of the distributor 60 when the rotational angle of the brush 91 matches the rotational angle of the distributor 60. The brush 91 then removes any solid matter adhering to the through-holes 61 of the distributor 60. As a result, in the sedimentation treatment apparatus 1, clogging of the through-hole 61 of the distributor 60 is suppressed, and the water to be treated is distributed into the sedimentation tank 10 with high accuracy, thereby improving sedimentation performance.

[0027] Furthermore, multiple through-holes 61 are formed so as to be aligned in the extending direction of the distributor 60, and the cleaning unit 90 has a single brush 91 for cleaning the multiple through-holes 61. As a result, the sedimentation apparatus 1 has a simpler configuration compared to, for example, a configuration having multiple brushes that can contact each of the multiple through-holes 61. Furthermore, the sedimentation treatment apparatus 1 does not necessarily need to be equipped with a cleaning unit 90.

[0028] Furthermore, the sedimentation treatment method performed by the sedimentation treatment apparatus 1 involves discharging the water to be treated from the distributor 60 and scraping the solid matter settled at the bottom 11 with the scraping unit 40, wherein the rotation speed of the distributor 60 is set lower than the rotation speed of the scraping unit 40. With this sedimentation treatment method, the upward flow velocity of the water to be treated in the sedimentation tank 10 can be reduced compared to the case where the rotation speed of the distributor 60 is equal to or greater than the rotation speed of the scraping unit 40, thereby improving the settling performance.

[0029] Furthermore, in the sedimentation treatment method performed by the sedimentation treatment apparatus 1, the cleaning unit 90, which is fixed to the scraping unit 40 and rotates together with the scraping unit 40, cleans the through-holes 61 formed in the distributor 60. As a result, clogging of the through-holes 61 in the distributor 60 is suppressed, and the water to be treated is distributed into the sedimentation tank 10 with high accuracy, thereby improving sedimentation performance.

[0030] Furthermore, a configuration in which the rotation speed of the distributor 60 is made smaller than the rotation speed of the scraping section 40 may be applied to a device that rapidly coagulates solid matter in the water to be treated by adding a nozzle for adding chemicals and a mixer for mixing and stirring the water to be treated with chemicals inside the supply member 20 and chamber 70, in addition to the components of the sedimentation treatment device 1. The means of adding the coagulant to the water to be treated supplied into the supply member 20 are not particularly limited. For example, the coagulant may be added to the water to be treated in the supply member 20 and chamber 70 by a nozzle (not shown) provided inside the supply member 20, or the coagulant may be added upstream of the supply pipe 30. Examples of coagulants include inorganic coagulants and polymer coagulants. The coagulant may be an inorganic coagulant or a polymer coagulant only, or an inorganic coagulant and a polymer coagulant may be used in combination.

[0031] <Second Embodiment> Figure 3 shows an example of a schematic configuration of the precipitation treatment apparatus 2 according to the second embodiment. The sedimentation apparatus 2 according to the second embodiment differs from the sedimentation apparatus 1 according to the first embodiment in that it rotates a distribution rotating shaft 280, which corresponds to the distribution rotating shaft 80. The differences from the first embodiment will be described below. The same reference numerals are used for the same components in the first and second embodiments, and their detailed descriptions will be omitted.

[0032] A spur gear 52 is fitted onto the scraping rotation shaft 50. An internal gear 281 that meshes with the spur gear 52 is fitted onto the distribution rotating shaft 280. The number of teeth on the internal gear 281 is greater than the number of teeth on the spur gear 52. Furthermore, the sedimentation processing apparatus 2 according to the second embodiment does not include a worm wheel 81, a distribution motor 82, or a worm 83.

[0033] In the sedimentation apparatus 2 according to the second embodiment configured as described above, when the scraping motor 51 rotates, the scraping rotating shaft 50 rotates, and when the scraping rotating shaft 50 rotates, the distribution rotating shaft 280 rotates. In other words, since the spur gear 52 fitted to the scraping rotating shaft 50 and the internal gear 281 fitted to the distribution rotating shaft 280 mesh, when the scraping rotating shaft 50 rotates, the distribution rotating shaft 280 rotates. Furthermore, since the number of teeth of the internal gear 281 is greater than the number of teeth of the spur gear 52, the rotational speed of the distribution rotating shaft 280 is smaller than the rotational speed of the scraping rotating shaft 50. In other words, the rotational speed of the distributor 60 is smaller than the rotational speed of the scraping section 40.

[0034] In the sedimentation apparatus 2, the rotation axis of the distribution rotation shaft 280 is set to be different from the rotation axis of the scraping rotation shaft 50, so that some of the teeth of the spur gear 52 fitted to the scraping rotation shaft 50 mesh with some of the teeth of the internal gear 281 fitted to the distribution rotation shaft 280. Also, the rotation axes of the chamber 70 and distributor 60 fixed to the distribution rotation shaft 280 are different from the rotation axis of the scraping rotation shaft 50. In other words, the rotation axes of the distribution rotation shaft 280, the chamber 70 and the distributor 60 are lines CL2 parallel to the center line CL, but line CL2 is different from the center line CL. Furthermore, the centerline of the supply member 20 that rotatably supports the chamber 70 is positioned differently from the centerline CL. For example, in the second embodiment, the centerline of the supply member 20 coincides with line CL2.

[0035] In the sedimentation apparatus 2, the distribution rotating shaft 280 rotates when the scraping rotating shaft 50 rotates, so there is only one drive source for the distributor 60 and the scraping unit 40, and the scraping motor 51 is the drive source. The control device 100 controls the drive of the scraping motor 51 so that the rotational speed of the scraping unit 40 is at a predetermined speed. As a result, the rotational speed of the distributor 60 becomes less than the predetermined speed. Therefore, the sedimentation treatment device 2 can reduce the upward flow velocity of the water to be treated in the sedimentation tank 10 compared to the case where the rotational speed of the distributor 60 is equal to or greater than the rotational speed of the scraping unit 40, thereby improving the settling performance. [Explanation of Symbols]

[0036] 1,2...Sedimentation processing device, 10...Sedimentation tank, 11...Bottom, 20...Supply member, 40...Scraping section, 50...Scraping rotating shaft (example of second rotating shaft), 51...Scraping motor, 60...Distributor, 61...Through hole, 70...Chamber, 80,280...Distribution rotating shaft (example of first rotating shaft), 82...Distribution motor, 90...Cleaning section, 91...Brush

Claims

1. A first rotating shaft for rotating the discharge section that discharges the treated water into the sedimentation tank, A second rotating shaft for rotating the scraping unit that scrapes the solid material settled in the sedimentation tank, Equipped with, The rotational speed of the first rotating shaft is less than the rotational speed of the second rotating shaft. Precipitation treatment device.

2. The first rotation axis is located outside the second rotation axis. The precipitation apparatus according to claim 1.

3. The drive source that rotates the first rotating shaft and the drive source that rotates the second rotating shaft are different, The precipitation apparatus according to claim 2.

4. The scraping portion is located below the discharge portion, The system further includes a cleaning unit provided at the upper part of the scraping unit, which rotates together with the scraping unit to clean the discharge holes formed in the discharge unit. The precipitation apparatus according to claim 1.

5. Multiple discharge holes are formed so as to be aligned in the extending direction of the discharge portion. The cleaning unit has a single brush for cleaning the multiple discharge holes. The precipitation apparatus according to claim 4.

6. A sedimentation treatment method comprising discharging water to be treated from a discharge section into a sedimentation tank and scraping the solid material settled in the sedimentation tank with a scraping section, The rotational speed of the first rotating shaft for rotating the discharge section is made smaller than the rotational speed of the second rotating shaft for rotating the scraping section. Precipitation treatment method.

7. A cleaning unit, fixed to the scraping unit and rotating together with the scraping unit, cleans the discharge hole formed in the discharge unit. The precipitation treatment method according to claim 6.

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