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 sedimentation tank for settling solid matter in water to be treated, and a discharge pipe for discharging the water to be treated into the sedimentation tank while rotating, wherein the discharge pipe has a plurality of discharge holes, and the plurality of discharge holes are arranged such that the position in the direction of the rotation axis of the outer discharge holes provided on the outside of the rotation axis of the discharge pipe is lower than the position in the direction of the rotation axis of the inner discharge holes provided on the inside of the rotation axis of the discharge pipe.

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 precipitation tank, and a blowing pipe having a plurality of blowing holes is provided at the tip of the feed supply pipe. In the precipitation treatment apparatus described in Patent Document 1, the treated water having flocs in the feed supply pipe is distributed and supplied to the precipitation space of the precipitation tank by the blowing pipe.

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 that the upward flow generated in the precipitation space of the precipitation tank is uniform throughout the entire area. If the discharge amount from each discharge hole (blowing hole in Patent Document 1) of the discharge pipe (blowing pipe in Patent Document 1) is not an appropriate discharge amount according to the position of the discharge hole, it becomes difficult for the upward flow generated in the precipitation space to be uniform throughout the entire area. On the other hand, when a plurality of discharge holes in the discharge pipe, such as the precipitation treatment apparatus described in Patent Document 1, are formed with the same size and at equal intervals, the discharge amount discharged from the outer discharge holes of the discharge pipe is more likely to be larger than that from the inner discharge holes. When the discharge amount discharged from the outer discharge holes is more than an appropriate discharge amount, a strong upward flow occurs around the inner peripheral part of the precipitation tank, and the upward flow generated in the precipitation space does not become uniform. Therefore, it is desirable to adjust the discharge amount of each discharge hole so that the upward flow generated in the precipitation space is uniform throughout the entire area. 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 sedimentation tank for settling solid matter in water to be treated, and a discharge pipe for discharging the water to be treated into the sedimentation tank while rotating, wherein the discharge pipe has a plurality of discharge holes, and the plurality of discharge holes are arranged such that the position in the direction of the rotation axis of the outer discharge holes, which are provided on the outside of the rotation axis of the discharge pipe, is lower than the position in the direction of the rotation axis of the inner discharge holes, which are provided on the inside of the rotation axis of the discharge pipe. Here, the discharge pipe may be designed such that the discharge volume from the outer discharge hole is greater than the discharge volume from the inner discharge hole. Furthermore, the discharge volume from the plurality of discharge holes may be designed to increase in proportion to the distance from the discharge hole to the rotation axis. Furthermore, the discharge pipe may be designed such that the ratio of the discharge volume from the inner discharge port to the annular region to which the treated water discharged from the inner discharge port is distributed is equal to the ratio of the discharge volume from the outer discharge port to the annular region to which the treated water discharged from the outer discharge port is distributed. Furthermore, the discharge pipe may extend in a straight line, and the direction of extension of the discharge pipe may be inclined with respect to the direction of rotational radius of the discharge pipe. Furthermore, a suppression member may be provided below the discharge hole to prevent the treated water discharged from the discharge hole from moving in a direction other than the vertical. Furthermore, from another perspective, the present invention is a sedimentation treatment method for which solid matter in water to be treated is settled by discharging the water to be treated into a sedimentation tank while rotating, wherein the discharge position in the direction of the rotation axis of the outer discharge holes, which are located outside the rotation axis among the plurality of discharge holes from which the water to be treated is discharged, is lower than the discharge position in the direction of the rotation axis of the inner discharge holes, which are located inside the rotation axis among the plurality of discharge holes from which the water to be treated is discharged. In this case, the discharge amount from the outer discharge hole may be greater than the discharge amount from the inner discharge hole. Furthermore, the discharge may be configured such that the ratio of the discharge volume from the inner discharge port to the annular region to which the treated water discharged from the inner discharge port is distributed is equal to the ratio of the discharge volume from the outer discharge port to the annular region to which the treated water discharged from the outer discharge port is distributed. [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 distributor's general configuration. [Figure 3] This figure shows an example of a cross-section of section III-III in Figure 1. [Figure 4] This figure shows an example of a schematic configuration of a distributor related to the comparative configuration. [Figure 5] This figure shows an example of a schematic configuration of a distributor related to a modified example. [Figure 6] 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. 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 rake 40 for scraping the concentrated sludge that has settled at the bottom of the sedimentation tank 10, and a shaft 50 for rotating the rake 40. The sedimentation treatment apparatus 1 also comprises a plurality (e.g., four) of distributors 60 located above the rake 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. The sedimentation treatment apparatus 1 also comprises a chamber 70 that holds the plurality of distributors 60 and stores the water to be treated until it is supplied to the distributors 60.

[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 rake 40 is for scraping and collecting the sludge that has settled and concentrated on the bottom surface in the sedimentation tank 10. The rake 40 is fixed to the shaft 50 and rotates together with the shaft 50. The shaft 50 is for rotating the rake 40. The shaft 50 is arranged vertically so that the center line CL coincides with the rotation axis. The upper end of the shaft 50 is connected to a drive source (for example, a motor) fixed to the top portion 15, and the lower end extends to the recess 12 at the bottom 11 of the sedimentation tank 10.

[0014] The chamber 70 holds a plurality of distributors 60 and stores the water to be treated until it is supplied to the distributor 60. The chamber 70 has a cylindrical cylindrical portion 71 and a bottom portion 72 provided so as to cover the lower opening in the cylindrical portion 71. A vertical through hole (not shown) is formed in the central portion of the bottom portion 72. The chamber 70 is fixed to the shaft 50, for example, by welding with the shaft 50 passed through the through hole. The outer peripheral surface of the upper end portion of the cylindrical portion 71 is arranged to face the inner peripheral surface of the lower end portion of the supply member 20. The chamber 70 rotates relative to the supply member 20 together with the shaft 50. A horizontal through hole (not shown) for allowing the inside and the outside to communicate with each other is formed at the lower end portion of the cylindrical portion 71. A plurality (for example, four) of horizontal through holes are formed at equal intervals in the circumferential direction. It can be exemplified that the shape of the horizontal through hole is circular when viewed in the horizontal direction.

[0015] 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 has a discharge portion 61 for discharging the water to be treated into the sedimentation tank 10, a connection portion 65 connecting the discharge portion 61 and the chamber 70, and a suppressing member 68 for suppressing the water to be treated discharged from the discharge portion 61 from heading in a direction other than the vertical direction. The distributor 60 will be described in detail later.

[0016] In the sedimentation treatment apparatus 1 configured as described above, the 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 a horizontal through-hole in the chamber 70 and is discharged into the sedimentation tank 10 from the discharge section 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 then discharged through a 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 raked towards the center by a rake 40 that 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 a draw pipe 13.

[0017] The following provides a detailed description of Distributor 60. Figure 2 shows an example of the schematic configuration of the distributor 60. The discharge section 61 of the distributor 60 has a cylindrical discharge pipe 62 and an annular flange section 63 provided at the inner end of the discharge pipe 62. The discharge pipe 62 extends from the centerline CL (see Figure 1) side of the sedimentation tank 10 towards the inner circumferential surface 17 side of the sedimentation tank 10, and has multiple (for example, 5 to 30; 10 in Figure 2) discharge holes 64 formed at its lower end. The multiple discharge holes 64 are formed to be arranged at equal intervals in the direction of extension, and the size of the discharge holes 64 is the same. The outer opening of the discharge pipe 62 is closed. The outer diameter of the flange portion 63 is larger than the outer diameter of the discharge pipe 62, and the flange portion 63 protrudes from the outer surface of the discharge pipe 62. Multiple through holes are formed around the discharge pipe 62 in the flange portion 63 through which the shaft portion of the bolt 69 passes. The flange portion 63 can be joined to the discharge pipe 62 by welding, for example.

[0018] The connecting portion 65 has a cylindrical connecting pipe 66 and an annular flange portion 67 provided at the outer end of the connecting pipe 66. The outer diameter of the flange portion 67 is larger than the outer diameter of the connecting pipe 66, and the flange portion 67 protrudes from the outer surface of the connecting pipe 66. Multiple through holes are formed around the connecting pipe 66 in the flange portion 67, through which the shaft portion of the bolt 69 passes. For example, the flange portion 67 can be joined to the connecting pipe 66 by welding.

[0019] The connecting pipes 66 are fixed, for example by welding, at their inner ends around the horizontal through-holes in the cylindrical portion 71 of the chamber 70. The connecting pipes 66 are welded to the chamber 70 such that their centerlines are inclined with respect to the rotational axis of the chamber 70. In other words, the connecting pipes 66 are welded to the chamber 70 such that their centerlines are inclined with respect to the horizontal direction. Multiple connecting pipes 66 are positioned to correspond to multiple horizontal through-holes formed in the chamber 70.

[0020] The discharge section 61 is fixed to the connecting section 65 by a bolt 69 and nut that passes through a through hole formed in the flange section 63 and a through hole formed in the flange section 67 of the connecting section 65. The mating surfaces of the flange section 63 of the discharge section 61 and the flange section 67 of the connecting section 65 are oriented perpendicular to the centerline direction of the connecting pipe 66. Therefore, the extension direction of the discharge pipe 62 is inclined with respect to the horizontal direction. Furthermore, the discharge pipe 62 is inclined such that the position of the outer discharge hole 642, which is on the inner circumferential surface 17 side (in other words, the outside) of the multiple discharge holes 64, is lower than the position of the inner discharge hole 641, which is on the centerline CL side (in other words, the inside) of the multiple discharge holes 64.

[0021] The suppression member 68 is a cylindrical tube, welded to the lower end of the discharge pipe 62 such that its centerline is vertical. Each suppression member 68 is welded around each discharge hole 64, and the inner diameter of the suppression member 68 is larger than the diameter of the discharge hole 64. The suppression member 68 then supplies all of the treated water discharged from the discharge hole 64 into the sedimentation tank 10. The multiple restraining members 68 are all positioned at the same vertical location at their lower ends. In other words, the restraining member 68 located at the position corresponding to the inner discharge hole 641 is the longest, and the restraining member 68 located at the position corresponding to the outer discharge hole 642 is the shortest, with the length gradually decreasing from the inside to the outside.

[0022] Next, we will elaborate on the fact that the extension direction of the discharge pipe 62 is inclined with respect to the horizontal direction. Figure 3 shows an example of a cross-section of section III-III in Figure 1. As shown in Figure 2, since the multiple discharge holes 64 of the discharge section 61 are formed at equal intervals in the extending direction, the multiple suppression members 68 are provided at equal intervals in the rotational radius direction of the shaft 50. When viewed in the vertical direction, the centers of the discharge holes 64 and the centers of the suppression members 68 are the same. When n suppression members 68 are provided, in other words, when n discharge holes 64 are formed, the area A(k) of the annular region to which the treated water discharged from the k-th (where k is an integer less than or equal to n) suppression member 68 (discharge hole 64) is distributed is given by the following equation (1). A(k) = π × (D(k)) 2 -D(k-1) 2 ) / 4···(1) Here, as shown in Figure 3, D(k) is the diameter at the midpoint between H(k) and H(k+1), where H(k) is the kth suppression member 68 (in other words, the discharge hole 64). Also, D(k-1) is the diameter at the midpoint between H(k) and H(k-1).

[0023] Then, if we let L (a constant) be the radial length between H(k) and H(k-1), then D(k-1) is given by equation (2) below. D(k-1) = D(k) - 2 × L···(2) Substituting equation (2) into equation (1) yields equation (3). A(k) = π × L × (D(k) - L) ... (3) Since L is a constant value, by equation (3), A(k) is proportional to D(k). Since D(k) is a value proportional to the radius of rotation, A(k) increases in proportion to the distance from the center line CL.

[0024] Furthermore, if Q(k) is the discharge volume of the treated water discharged from H(k), and the ratio V(k) of Q(k) to A(k) is constant at any discharge port 64 of the distributor 60 (Q(k) / A(k) = constant), then the upward flow generated within the sedimentation space in the sedimentation tank 10 becomes uniform throughout the entire sedimentation tank 10, and the sedimentation performance is considered to be high. Since A(k) increases in proportion to the distance from the center line CL, it is desirable that Q(k) also increases in proportion to the distance from the center line CL. The "sedimentation space" of the sedimentation apparatus 1 refers to the space within the sedimentation tank 10 excluding the supply member 20, the distributor 60, and the chamber 70.

[0025] Figure 4 shows an example of the schematic configuration of distributor 560 related to the comparative configuration. The distributor 560 in the comparative configuration differs from the distributor 60 in that the extension direction of the discharge section 561, which corresponds to the discharge section 61, and the connection section 565, which corresponds to the connection section 65, is horizontal.

[0026] In the distributor 560 of the comparative configuration, the discharge pipe 562, which corresponds to the discharge pipe 62, extends horizontally. Therefore, in the distributor 560, the vertical position of the innermost discharge hole 5641, which is formed in the discharge pipe 562, and the vertical position of the outermost discharge hole 5642, which is formed in the outermost part, are the same.

[0027] As a result of diligent research by the inventors, it was found that in the distributor 560 of the comparative configuration, the ratio V(n) at the outer discharge port 5642 is greater than the ratio V(1) at the inner discharge port 5641. That is, the ratio V(n) of the discharge volume Q(n) and A(n) of the treated water discharged from the outer discharge port 5642 is greater than the ratio V(1) of the discharge volume Q(1) and A(1) of the treated water discharged from the inner discharge port 5641 (Q(n) / A(n)>Q(1) / A(1)).

[0028] This is because the pressure at the outer discharge port 5642 inside the discharge pipe 562 is higher than the pressure at the inner discharge port 5641 inside the discharge pipe 562, so the discharge volume Q(n) of the treated water discharged from the outer discharge port 5642 becomes too large compared to the discharge volume Q(1) discharged from the inner discharge port 5641. In other words, according to equation (3) above, A(k) is proportional to D(k), or in other words, the distance from the center line CL, so it is preferable that the discharge volume discharged from the discharge port 564 increases in proportion to the distance from the center line CL, but it becomes greater than the appropriate discharge volume according to the position of the discharge port 564. According to the results of the inventors' diligent studies, the discharge volume discharged from the discharge port 564 increases approximately in proportion to the square of the distance from the center line CL. Therefore, in the distributor 560 of the comparative configuration, the ratio V(n) at the outer discharge port 5642 becomes larger than the ratio V(1) at the inner discharge port 5641.

[0029] In contrast, in the sedimentation apparatus 1 according to the first embodiment, the extension direction of the discharge pipe 62 is inclined with respect to the horizontal direction such that the position of the outer discharge hole 642 is lower than the position of the inner discharge hole 641, so the ratio V(k) of Q(k) to A(k) tends to remain constant. That is, the lower the position of the discharge hole 64, the higher the hydrostatic pressure generated at the discharge hole 64, so the further out the discharge hole 64 is located, the smaller the discharge volume compared to the distributor 560 in the comparative configuration. In other words, the difference between the discharge volume from the inner discharge hole 64 and the discharge volume from the outer discharge hole 64 in the discharge pipe 562 of the distributor 560 in the comparative configuration is smaller than the difference between the discharge volume from the inner discharge hole 564 and the discharge volume from the outer discharge hole 564 in the discharge pipe 562 of the distributor 560 in the comparative configuration. Therefore, in the distributor 560 of the comparative configuration, the ratio V(n) at the outer discharge port 5642 is larger than the ratio V(1) at the inner discharge port 5641 and is not constant. However, in the distributor 60 of this embodiment, the ratio V(n) at the outer discharge port 642 and the ratio V(1) at the inner discharge port 641 tend to be the same. As a result, in the distributor 60 of this embodiment, the ratio V(k) of Q(k) and A(k) tends to be more constant than in the distributor 560 of the comparative configuration.

[0030] As described above, the sedimentation apparatus 1 comprises a cylindrical sedimentation tank 10 having a bottom 11 for settling solids in the water to be treated, and a discharge pipe 62 that extends from the centerline CL side of the sedimentation tank 10 toward the inner circumferential surface 17 side and rotates with the centerline CL as the axis of rotation, and discharges the water to be treated into the sedimentation tank 10 from a plurality of discharge holes 64 that are arranged in the direction of extension. The discharge pipe 62 is positioned such that the position of the outer discharge hole 642, which is on the inner circumferential surface 17 side (in other words, outside the axis of rotation) of the plurality of discharge holes 64, is lower than the position of the inner discharge hole 641, which is on the axis of rotation side (in other words, inside the axis of rotation) of the plurality of discharge holes 64.

[0031] According to the sedimentation apparatus 1, the ratio V(1) of the discharge volume Q(1) of the treated water discharged from the inner discharge hole 641 to A(1) is more likely to match the ratio V(n) of the discharge volume Q(n) of the treated water discharged from the outer discharge hole 642 to A(n). In other words, according to the sedimentation apparatus 1, although the discharge volume Q(n) discharged from the outer discharge hole 642 is set to be greater than the discharge volume Q(1) discharged from the inner discharge hole 641, the discharge volume Q(n) does not become excessively greater than the discharge volume Q(1). Therefore, compared to the apparatus equipped with the distributor 560 in the comparative configuration, the sedimentation apparatus 1 is more likely to have equal upward flow generated in the sedimentation space within the sedimentation tank 10 in the annular region corresponding to the inner discharge hole 641 and the annular region corresponding to the outer discharge hole 642. As a result, the sedimentation apparatus 1 has improved sedimentation performance compared to the apparatus equipped with the distributor 560 in the comparative configuration. Therefore, the sedimentation treatment device 1 can increase the amount of water to be treated while keeping the size of the sedimentation tank 10 the same.

[0032] In the sedimentation apparatus 1 according to the first embodiment, the discharge pipe 62 extends linearly, and the direction of extension of the discharge pipe 62 is inclined with respect to the radial direction of rotation of the discharge pipe 62 (in other words, the horizontal direction). As a result, the amount of discharged material ejected from the discharge hole 64 tends to increase in proportion to the distance from the center line CL, so that the above ratio V(k) tends to remain constant. The inclination angle of the extension direction of the discharge pipe 62 with respect to the horizontal direction should be set appropriately according to the specifications of the sedimentation apparatus 1 so that the above ratio V(k) remains constant.

[0033] Furthermore, the sedimentation apparatus 1 has a suppression member 68 below the discharge hole 64 that prevents the treated water discharged from the discharge hole 64 from moving in directions other than the vertical. If the suppression member 68 is not provided below the discharge hole 64, the treated water discharged from the discharge pipe 62 tends to move inward due to the extension direction of the discharge pipe 62 being inclined with respect to the horizontal. In contrast, since the sedimentation apparatus 1 is provided with a suppression member 68, the treated water discharged from the discharge hole 64 tends to move downward. As a result, with the sedimentation apparatus 1, the upward flow generated in the sedimentation space within the sedimentation tank 10 tends to become uniform throughout the entire sedimentation tank 10, thus improving sedimentation. However, the sedimentation apparatus 1 does not necessarily have to be equipped with a suppression member 68.

[0034] Furthermore, the sedimentation method performed by the sedimentation apparatus 1 involves extending from the centerline CL side to the inner circumferential surface 17 side and rotating with the centerline CL as the axis of rotation, while discharging the water to be treated into the sedimentation tank 10 from a plurality of discharge holes 64 that are arranged in the direction of extension, thereby settling the solid matter in the water to be treated. In the sedimentation method performed by the sedimentation apparatus 1, the discharge position from the outer discharge hole 642, which is on the inner circumferential surface 17 side of the plurality of discharge holes 64, is lower than the discharge position from the inner discharge hole 641, which is on the axis of rotation side of the plurality of discharge holes 64. The sedimentation method performed by the sedimentation apparatus 1 improves sedimentation performance compared to the sedimentation method performed by an apparatus equipped with a distributor 560 in the comparative configuration. Therefore, the sedimentation method performed by the sedimentation apparatus 1 makes it possible to increase the amount of water to be treated while keeping the size of the sedimentation tank 10 the same.

[0035] Furthermore, the sedimentation treatment method performed by the sedimentation treatment apparatus 1 is such that the discharge volume from the outer discharge port 642 is greater than the discharge volume from the inner discharge port 641. Furthermore, the sedimentation treatment method performed by the sedimentation treatment apparatus 1 is such that the ratio V(1) of the discharge volume from the inner discharge port 641 to the annular region to which the treated water discharged from the inner discharge port 641 is distributed is equal to the ratio V(n) of the discharge volume from the outer discharge port 642 to the annular region to which the treated water discharged from the outer discharge port 642 is distributed.

[0036] Furthermore, the distributor 60 may be applied to a device that rapidly coagulates solids by further equipping the supply member 20 and chamber 70 with nozzles for adding chemicals and a mixer for mixing and stirring the water to be treated with the chemicals, 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.

[0037] Furthermore, in the above-described embodiment, the configuration in which the extension direction of the discharge pipe 62 is inclined with respect to the horizontal direction is achieved by welding the connecting pipe 66 to the chamber 70 such that the centerline direction of the connecting pipe 66 is inclined with respect to the rotation axis direction of the chamber 70. However, the method for achieving the configuration in which the extension direction of the discharge pipe 62 is inclined with respect to the horizontal direction is not particularly limited.

[0038] (A modified version of Distributor 60) Figure 5 shows an example of a schematic configuration of a modified distributor 160. The modified distributor 160 differs from the distributor 60 in that it has a discharge section 161 corresponding to the discharge section 61 and a connection section 165 corresponding to the connection section 65. The differences from the distributor 60 will be explained below. The same reference numerals are used for parts that are the same in the distributor 60 and the distributor 160, and their detailed explanations will be omitted.

[0039] Unlike the connection part 65, the modified connection part 165 is joined to the chamber 70 such that the centerline direction of the connecting pipe 66 is horizontal. Also, the mating surface between the flange part 63 and the flange part 63 of the flange part 67 of the connection part 65 is perpendicular to the centerline direction of the connecting pipe 66, in other words, perpendicular to the horizontal direction.

[0040] In the modified discharge section 161, unlike the discharge section 61, the mating surface between the flange section 63 and the flange section 67 is oriented perpendicular to the horizontal direction. The discharge pipe 62 is joined to the flange section 63 such that the centerline direction of the discharge pipe 62 is inclined with respect to the horizontal direction. Even with the above configuration, the extension direction of the discharge pipe 62 can be tilted with respect to the horizontal direction.

[0041] Unlike the modified distributor 160, the flange portion 67 of the connecting portion 65 may be joined to the connecting pipe 66 such that the mating surface between the flange portion 63 and the flange portion 67 of the connecting portion 65 is inclined with respect to a direction perpendicular to the centerline direction of the connecting pipe 66. In this configuration, the extension direction of the discharge pipe 62 can be inclined with respect to the horizontal direction by connecting the discharge portion 61 to the flange portion 67, similar to the embodiment shown in Figure 1.

[0042] <Second Embodiment> Figure 6 shows an example of a schematic configuration of the precipitation treatment apparatus 2 according to the second embodiment. The precipitation apparatus 2 differs from the precipitation apparatus 1 according to the first embodiment in that it has a distributor 260 that corresponds to the distributor 60. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and second embodiments, and their detailed descriptions will be omitted.

[0043] The distributor 260 differs from the distributor 60 according to the first embodiment in that it has a discharge section 261 corresponding to the discharge section 61 and a connection section 265 corresponding to the connection section 65. Unlike connection part 65, connection part 265 is joined to the chamber 70 such that the centerline direction of the connecting pipe 66 is horizontal. Also, the mating surface between the flange portion 63 and the flange portion 67 of connection part 65 is perpendicular to the centerline direction of the connecting pipe 66. In other words, connection part 265 is the same as connection part 165 in the modified example described with reference to Figure 5.

[0044] Unlike the discharge section 61, the mating surface between the flange section 63 and the flange section 67 of the discharge section 261 is oriented perpendicular to the horizontal direction. Furthermore, the discharge section 261 has a discharge pipe 262 instead of the discharge pipe 62 according to the first embodiment. Unlike the discharge pipe 62, the discharge pipe 262 is curved so that the inner circumferential surface 17 side of the sedimentation tank 10 is located lower than the centerline CL side. And, among the multiple discharge holes 264 formed in the discharge pipe 262, the position of the outer discharge hole 2642, which is on the inner circumferential surface 17 side, is located lower than the position of the inner discharge hole 2641, which is on the centerline CL side.

[0045] The discharge pipe 262 has an inner end that is horizontal, and the center line of the inner end is perpendicular to the mating surface with the flange portion 67 in the flange portion 63. Furthermore, the discharge pipe 262 may have an outer end that is inclined to the horizontal and has an arc shape between the inner and outer ends. Alternatively, the discharge pipe 262 may have an inner end that is horizontal and an overall arc shape from the inner end to the outer end.

[0046] Even with the above configuration of the distributor 260, the position of the outer discharge hole 2642, which is on the inner circumferential surface 17 side of the multiple discharge holes 264, can be positioned lower than the position of the inner discharge hole 2641 in the discharge pipe 262. As a result, the settling performance of the sedimentation treatment device 2 is improved compared to a device equipped with the distributor 260 according to the comparative configuration. Therefore, the settling treatment device 2 can increase the amount of water to be treated while keeping the size of the settling tank 10 the same. [Explanation of symbols]

[0047] 1,2...Sedimentation apparatus, 10...Sedimentation tank, 20...Supply member, 21...Opening, 30...Supply pipe, 40...Rake, 50...Shaft, 60...Distributor, 61...Discharge section, 62...Discharge pipe, 63,67...Flange section, 64...Discharge hole, 65...Connection section, 66...Connection pipe, 68...Suppression member, 70...Chamber, 641...Inner discharge hole, 642...Outer discharge hole

Claims

1. A sedimentation tank for settling solid matter in the water to be treated, A discharge pipe that discharges the water to be treated into the sedimentation tank while rotating, Equipped with, The discharge pipe has a plurality of discharge holes, The plurality of discharge holes are arranged such that the position in the direction of the rotation axis of the outer discharge holes, which are located outside the rotation axis of the discharge pipe, is lower than the position in the direction of the rotation axis of the inner discharge holes, which are located inside the rotation axis of the discharge pipe. Precipitation treatment device.

2. The discharge pipe is designed such that the discharge volume from the outer discharge port is greater than the discharge volume from the inner discharge port. The precipitation apparatus according to claim 1.

3. The discharge volume from the plurality of discharge holes is designed to increase in proportion to the distance from the discharge hole to the rotation axis. The precipitation apparatus according to claim 1.

4. The discharge pipe is designed such that the ratio of the discharge volume from the inner discharge port to the annular region to which the treated water discharged from the inner discharge port is distributed is equal to the ratio of the discharge volume from the outer discharge port to the annular region to which the treated water discharged from the outer discharge port is distributed. The precipitation apparatus according to claim 1.

5. The discharge pipe extends linearly, and the direction of extension of the discharge pipe is inclined with respect to the direction of rotational radius of the discharge pipe. The precipitation apparatus according to claim 1.

6. Below the discharge hole, there is a suppression member that prevents the treated water discharged from the discharge hole from moving in a direction other than the vertical. The precipitation apparatus according to claim 5.

7. A sedimentation treatment method in which solid matter in the water to be treated is settled by discharging the water to be treated into a sedimentation tank while rotating it, The discharge position in the direction of the rotation axis of the outer discharge hole, which is located outside the rotation axis of the plurality of discharge holes for discharging the treated water, is lower than the discharge position in the direction of the rotation axis of the inner discharge hole, which is located inside the rotation axis of the plurality of discharge holes for discharging the treated water. Precipitation treatment method.

8. Discharge is performed such that the discharge amount from the outer discharge hole is greater than the discharge amount from the inner discharge hole. The precipitation treatment method according to claim 7.

9. The discharge is performed such that the ratio of the discharge volume from the inner discharge port to the annular region to which the treated water discharged from the inner discharge port is distributed is equal to the ratio of the discharge volume from the outer discharge port to the annular region to which the treated water discharged from the outer discharge port is distributed. The precipitation treatment method according to claim 7.

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