Precipitation treatment equipment

Abstract

The present invention provides a sedimentation apparatus that can improve the settling properties of solids in water to be treated. [Solution] A sedimentation apparatus comprising: a sedimentation tank for separating solid and liquid water to be treated; a supply member provided inside the sedimentation tank for receiving water to be treated through an opening formed on its side and supplying water to be treated downward to the sedimentation tank; a supply pipe for supplying water to be treated to the supply member in a direction intersecting a first direction which is the direction of the centerline of the supply member; and a flow straightening member provided inside the supply member for changing the flow of water to be treated supplied from the supply pipe through an opening, wherein the flow straightening member has at least an opposing portion having an opposing surface facing the opening so as to intersect a second direction which is the direction of the centerline of the supply pipe, and a bottom portion provided below the opening so as to connect the opposing portion and the supply member, and the opposing portion and the bottom portion extend along the inner surface of the supply member in directions intersecting the first and second directions on both sides of the opposing surface.

Description

Technical Field

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

Background Art

[0002] The precipitation treatment apparatus described in Patent Document 1 includes a feed well which is a cylindrical body arranged upright in the center of a sedimentation tank. This feed well introduces the liquid to be treated from its side through an inflow pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the precipitation treatment apparatus described in Patent Document 1, there was room for improvement in terms of sedimentation performance. Since the diameter of the inflow pipe is smaller than the diameter of the feed well, the water to be treated flowing into the feed well is directly supplied to the inside of the sedimentation tank, and also because the supply speed is high, there is a risk that the sedimentation speed of solids inside the sedimentation tank will decrease. An object of the present invention is to provide a precipitation treatment apparatus capable of improving the sedimentation performance of solids in the liquid to be treated.

Means for Solving the Problems

[0005] The present invention, completed with this objective in mind, is a sedimentation apparatus comprising: a sedimentation tank for separating solid and liquid water to be treated; a supply member provided inside the sedimentation tank for receiving the water to be treated through an opening formed on its side and supplying the water to be treated downward to the sedimentation tank; a supply pipe for supplying the water to be treated to the supply member in a direction intersecting a first direction which is the direction of the centerline of the supply member; and a flow straightening member provided inside the supply member for changing the flow of the water to be treated supplied from the supply pipe through the opening, wherein the flow straightening member has at least an opposing portion having an opposing surface facing the opening so as to intersect a second direction which is the direction of the centerline of the supply pipe, and a bottom portion provided below the opening so as to connect the opposing portion and the supply member, and the opposing portion and the bottom portion extend along the inner surface of the supply member in directions intersecting the first and second directions on both sides of the opposing surface. Here, the rectifying member may have an arc shape when viewed in the first direction. Furthermore, the rectifying member may have a circular shape when viewed in the first direction. Furthermore, a through hole in the vertical direction may be formed in the bottom portion. Furthermore, the rectifying member may have a cover portion provided above the opening. Furthermore, the supply member may also be further equipped with an additive section for adding chemicals inside. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a sedimentation treatment apparatus 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 cross-section of section II-II in Figure 1. [Figure 3] This figure shows an example of a cross-section of section III-III in Figure 1. [Figure 4]This is an example of a diagram showing the rectifying member according to the first modified example, viewed vertically downward. [Figure 5] This is an example of a diagram showing the rectifying member according to the second modified example, viewed vertically downward. [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 the water to be treated to 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 used to scrape up the sludge that has settled and concentrated at the bottom of 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 positioned vertically such that its centerline CL coincides with the axis of rotation. The upper end of the shaft 50 is connected to a drive source (e.g., a motor) fixed to the top 15, and the lower end extends to a recess 12 in the bottom 11 of the sedimentation tank 10.

[0014] The chamber 70 holds a plurality of distributors 60 and is for storing 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 by welding, for example, 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 is formed in 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 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 wall 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. Note that 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, twenty) of through-holes 61 are formed at equal intervals in the horizontal direction.

[0016] In the precipitation treatment apparatus 1 configured as described above, the water to be treated containing solids is supplied into the supply member 20 through the supply pipe 30. The water to be treated containing solids reaches the distributor 60 through 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. Then, while the solids settle to the lower part of the sedimentation tank 10, a clarified layer, which is the supernatant, is formed in the upper part of the sedimentation tank 10, and the clarified treated water W1 is discharged by the discharge part 16 provided in the upper part of the sedimentation tank 10. Also, at the bottom 11 of the sedimentation tank 10, the sludge formed by the settled solids is concentrated by the rake 40 rotating around the center line CL and scraped towards the central part. When the pump is driven, the sludge settled in the recess 12 of the bottom 11 is drawn out of the sedimentation tank 10 through the draw-out pipe 13.

[0017] The precipitation treatment apparatus 1 configured as described above further includes a rectifying member 100 provided inside the supply member 20 for changing the flow of the water to be treated supplied from the supply pipe 30 through the opening 21. FIG. 2 is a diagram showing an example of a cross-section of part II-II in FIG. 1. FIG. 2 is also an example of a diagram of the rectifying member 100 viewed from above. FIG. 3 is a diagram showing an example of a cross-section of part III-III in FIG. 1. Hereinafter, the rectifying member 100 will be described in detail using FIGS. 1, FIG. 2 and FIG. 3.

[0018] The rectifying member 100 is for changing the flow of the water to be treated supplied from the supply pipe 30. The rectifying member 100 has a cylindrical cylindrical part 110 and a bottom part 120 that protrudes outward from the lower end of the cylindrical part 110 and is connected to the inner peripheral surface 22 of the supply member 20. The bottom part 120 is a part parallel to the horizontal direction and is provided over the entire circumference. That is, the shape of the rectifying member 100 is circular when viewed in the vertical direction. And the rectifying member 100 is fixed to the supply member 20 by joining the outer end of the bottom part 120 to the inner peripheral surface 22 of the supply member 20 by, for example, welding.

[0019] The cylindrical portion 110 is positioned so that its vertical position overlaps with the opening 21 of the supply member 20. Since the cylindrical portion 110 is cylindrical, it has a facing surface 111 that faces the opening 21 of the supply member 20. The outer diameter of the cylindrical portion 110 can be exemplified as 60% to 90% of the diameter of the inner circumferential surface 22 of the supply member 20.

[0020] The rectifying member 100 has a cover portion 130 provided above the opening 21. The cover portion 130 is a portion parallel to the horizontal direction and protrudes outward from the upper end of the cylindrical portion 110 to the inner circumferential surface 22 of the supply member 20. The outer end of the cover portion 130 may be fixed to the supply member 20 by joining it to the inner circumferential surface 22 of the supply member 20, for example by welding.

[0021] As the lid portion 130 extends from the cylindrical portion 110 to the inner circumferential surface 22 of the supply member 20, the lid portion 130 closes the gap between the cylindrical portion 110 and the inner circumferential surface 22 of the supply member 20 above the opening 21. On the other hand, in the areas where the lid portion 130 is not provided in the circumferential direction, the gap between the upper part of the cylindrical portion 110 and the inner circumferential surface 22 of the supply member 20 is not closed, and the area above the rectifying member 100 is open.

[0022] Vertical through-holes 121 are formed in the bottom portion 120. The through-holes 121 are formed over a predetermined angle (for example, from 15 to 35 degrees) in the circumferential direction. Multiple through-holes 121 (four in Figure 2) are formed at equal intervals in the circumferential direction. The through-holes 121 are formed over the entire area between the cylindrical portion 110 and the inner circumferential surface 22 of the supply member 20. The area in which the multiple through-holes 121 are formed relative to the area of ​​the bottom portion 120 (in other words, the total area of ​​the gap between the cylindrical portion 110 and the inner circumferential surface 22 of the supply member 20 when viewed in the vertical direction) can be exemplified as 30%. Note that the through-holes 121 are not formed below the opening 21. Furthermore, the through-holes 121 do not necessarily have to be formed over the entire area between the cylindrical portion 110 and the inner circumferential surface 22 of the supply member 20.

[0023] The flow straightening member 100 configured as described above prevents the treated water flowing into the supply member 20 from the opening 21 via the supply pipe 30 from flowing directly downwards (in other words, from creating a short path). In other words, the treated water flowing into the supply member 20 from the opening 21 hits the opposing surface 111 of the cylindrical portion 110 and flows circumferentially through the space S surrounded by the cylindrical portion 110, the bottom portion 120, and the inner circumferential surface 22 of the supply member 20. In addition, some of the treated water that hits the opposing surface 111 of the cylindrical portion 110 flows upwards, but since a lid portion 130 is provided above the opening 21, the treated water that hits the opposing surface 111 is prevented from flying out of the flow straightening member 100 over the top of the cylindrical portion 110 without flowing circumferentially. The treated water that flows circumferentially through the space S then flows downwards through the multiple through holes 121 formed in the bottom portion 120, or flows downwards over the top of the cylindrical portion 110.

[0024] As described above, the water to be treated that flows into the supply member 20 via the supply pipe 30 disperses into the multiple through holes 121 formed in the bottom 120 and flows downward. Furthermore, the multiple through holes 121 are formed evenly in the circumferential direction. Therefore, the water to be treated disperses easily in the circumferential direction within the chamber 70, and solid matter is more easily dispersed and formed in the circumferential direction. In other words, the flow velocity distribution inside the supply member 20 becomes more even in the circumferential direction, and the flow velocity decreases. Then, the water to be treated containing solid matter is more easily dispersed and flows into the multiple distributors 60, and is more easily supplied evenly from the multiple distributors 60 into the sedimentation tank 10. Therefore, the solid matter is more easily settled evenly in the sedimentation tank 10, and the settling velocity increases. That is, since the sedimentation treatment device 1 is equipped with a flow straightening member 100, the settling performance is improved compared to a configuration without a flow straightening member 100.

[0025] As described above, the sedimentation apparatus 1 comprises a sedimentation tank 10 for settling solid matter in the water to be treated, and a supply member 20 provided cylindrically inside the sedimentation tank 10, which receives the water to be treated through an opening 21 formed on its side and supplies the water to be treated downward from its lower end. The sedimentation apparatus 1 also comprises a supply pipe 30 that supplies the water to be treated from outside the sedimentation tank 10 to the supply member 20 in a direction intersecting the vertical direction (an example of a first direction) which is the centerline direction of the supply member 20. The sedimentation apparatus 1 also comprises a flow straightening member 100 provided inside the supply member 20 that changes the flow of the water to be treated supplied from the supply pipe 30 through the opening 21. The flow straightening member 100 has a cylindrical portion 110 (an example of an opposing portion) having at least an opposing surface 111 that faces the opening 21 so as to intersect with the horizontal direction (an example of a second direction) which is the centerline direction of the supply pipe 30. The flow straightening member 100 also has a bottom portion 120 provided below the opening 21 so as to connect the cylindrical portion 110 and the supply member 20. Furthermore, the rectifying member 100 has a circular shape when viewed in the vertical direction. That is, the cylindrical portion 110 and the bottom portion 120 are provided around the entire circumference of the supply member 20. In other words, the cylindrical portion 110 and the bottom portion 120 extend on both sides of the opposing surface 111 in a circumferential direction that intersects the vertical and horizontal directions along the inner circumferential surface 22 (an example of the inner surface) of the supply member 20. Therefore, the sedimentation treatment device 1 can suppress the occurrence of short paths and improve sedimentation. As a result, with the sedimentation treatment device 1, it is possible to increase the amount of water to be treated without changing the size of the sedimentation tank 10.

[0026] Furthermore, the rectifying member 100 has a cover portion 130 provided above the opening 21. This prevents the water to be treated, which strikes the opposing surface 111 of the cylindrical portion 110, from flying out of the rectifying member 100 beyond the portion of the cylindrical portion 110 above the opposing surface 111. For example, the circumferential size of the cover portion 130 can be said to be greater than or equal to the circumferential size of the opening 21 (for example, the diameter of the opening 21). For example, the cover portion 130 may be formed over a range of 10 to 20 degrees in the circumferential direction.

[0027] Furthermore, through holes 121 are formed in the bottom portion 120. As a result, the water to be treated flows downward through the through holes 121, preventing all of the water that flows circumferentially along the bottom portion 120 from flowing downward beyond the top of the cylindrical portion 110. Note that the number of through holes 121 is not limited to four. Also, the opening ratio is not limited to 30%.

[0028] In the embodiment described above, the flow straightening member 100 is applied to a sedimentation apparatus 1 in which a distributor 60 and a chamber 70 are provided below the supply member 20. However, the flow straightening member 100 may also be applied to a sedimentation apparatus in which a distributor 60 and a chamber 70 are not provided below the supply member 20, and the water to be treated containing solid matter is supplied directly from the lower end of the supply member 20 to the sedimentation tank 10.

[0029] (First modified example of the rectifier member 100) The shape of the through hole 121 formed in the bottom portion 120 of the rectifier member 100 is not limited to a shape formed over a predetermined angle. Figure 4 is an example of a view of the rectifying member 200 according to the first modified example, viewed vertically downward. The rectifier member 200 according to the first modified example differs from the rectifier member 100 in that its bottom portion 220 corresponds to the bottom portion 120. The differences from the rectifier member 100 will be explained below. The same reference numerals are used for parts that are the same in the rectifier member 100 and the rectifier member 200, and their detailed explanations will be omitted.

[0030] The flow straightening member 200 differs from the flow straightening member 100 in that it has through holes 221 corresponding to the through holes 121. The through holes 221 are circular in shape when viewed vertically and are smaller than the through holes 121, and multiple through holes are formed throughout the entire bottom portion 120. The opening ratio is not particularly limited, but for example, it can be exemplified as 30%. Because multiple through holes 221 are formed in the bottom portion 220, the water to be treated is more easily dispersed circumferentially within the chamber 70, and solid matter is more easily dispersed and formed circumferentially. As a result, even with the flow straightening member 200, the settling properties can be improved. Furthermore, the through-hole 221 does not necessarily have to be formed in the region below the opening 21.

[0031] (Second modified example of the rectifier member 100) The shape of the rectifier member 100 when viewed in the vertical direction is not limited to a circle. Figure 5 is an example of a view of the rectifier member 300 according to the second modified example, viewed vertically downward. The rectifier member 300 according to the second modified example differs from the rectifier member 100 in that the cylindrical portion 310 and the bottom portion 320, which correspond to the cylindrical portion 110 and bottom portion 120, respectively, are different. The differences from the rectifier member 100 will be explained below. The same reference numerals are used for parts that are the same in the rectifier member 100 and the rectifier member 300, and their detailed explanations will be omitted.

[0032] The rectifier member 300 has an arc shape when viewed in the vertical direction. That is, the cylindrical portion 310 and the bottom portion 320 are not provided around the entire circumference of the supply member 20, but are formed along the inner circumferential surface 22 of the supply member 20 at an angle of, for example, 45 degrees, and extend to both sides of the opposing surface 111.

[0033] Even with the flow straightening member 300 configured as described above, the water to be treated that flows into the supply member 20 from the opening 21 of the supply member 20 via the supply pipe 30 is prevented from going directly downward (in other words, from creating a short path). Specifically, the water to be treated that hits the opposing surface 111 of the cylindrical portion 310 goes to both sides in the circumferential direction and then downward from both ends of the cylindrical portion 310 and the bottom portion 320. In addition, some of the water to be treated that goes downward from the ends of the cylindrical portion 310 and the bottom portion 320 goes downward in a spiral along the inner circumferential surface 22 of the supply member 20. As a result, even with the flow straightening member 200, the settling properties can be improved. Furthermore, a through hole 221 may be formed in the bottom portion 320.

[0034] <Second Embodiment> Figure 6 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 mainly in that it is equipped with a nozzle 80 for adding chemicals and a mixer 90 for mixing and stirring the water to be treated with the chemicals. 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.

[0035] The nozzle 80 is an example of an additive section for adding chemicals to the inside of the supply member 20. The nozzle 80 is provided so as to extend from the outside to the inside of the supply member 20. The sedimentation treatment device 2 is provided with a plurality of nozzles 80 so as to be able to add chemicals above and below the opening 21 of the supply member 20. Examples of chemicals include flocculants, pH adjusters such as caustic soda, and disinfectants such as chlorine, which will be described in detail later.

[0036] The mixer 90 has a cylindrical rotating member 91 positioned on the outside of the shaft 50 and a protruding portion 92 that protrudes outward from the outer circumferential surface of the rotating member 91. The mixer 90 is provided inside the cylindrical portion 110 of the rectifier member 100. The rotating member 91 is positioned vertically such that its centerline CL coincides with the axis of rotation. The rotating member 91 is connected to a different drive source (e.g., a motor) than the drive source of the shaft 50. The rotating member 91 rotates at a rotational speed greater than the rotational speed of the shaft 50. The protruding portion 92 is a rectangular, flat plate-like part, and it can be exemplified that there are multiple protruding portions 92 in the circumferential direction at multiple locations (for example, 3 locations) in the vertical direction, and at each of these locations, there are multiple protruding portions 92 (for example, 4).

[0037] In the sedimentation apparatus 2, when the water to be treated is introduced into the supply member 20 and a coagulant is added as a chemical from the nozzle 80, stirring occurs by the rotation of the mixer 90, causing the solid matter in the water to be treated to rapidly coagulate and form flocs. Furthermore, because the sedimentation apparatus 2 is equipped with a flow straightening member 100, the water to be treated is more easily supplied evenly into the supply member 20 via the flow straightening member 100, making it easier for flocs to be dispersed and formed within the supply member 20 and the chamber 70. The water to be treated, containing the flocs, is then more easily dispersed and flows into the multiple distributors 60, and is more easily supplied evenly from the multiple distributors 60 into the sedimentation tank 10. Therefore, the flocs are more easily settled evenly in the sedimentation tank 10, and the settling velocity increases. In other words, because the sedimentation apparatus 2 is equipped with a flow straightening member 100, the settling performance is improved compared to a configuration without a flow straightening member 100.

[0038] Examples of flocculants include inorganic flocculants and polymer flocculants. The flocculant may consist of only an inorganic flocculant or a polymer flocculant, or a combination of both. When using both inorganic and polymer flocculants, it is preferable to add the inorganic flocculant and then the polymer flocculant to the water to be treated. This enables stable floc formation.

[0039] Inorganic flocculants are flocculants based on inorganic substances such as metal salts. Specific examples of inorganic flocculants include Al-based inorganic flocculants such as aluminum sulfate and PAC, and Fe-based inorganic flocculants such as polyferrous sulfate and ferric chloride. Polymer flocculants are flocculants based on organic polymer compounds. Specific examples of polymer flocculants include cationic polymer flocculants such as polyaminoalkyl methacrylate, polyethyleneimine, halide polydiallylammonium, chitosan, and urea-formaldehyde resin; anionic polymer flocculants such as sodium polyacrylate, partially hydrolyzed polyacrylamide, partially sulfomethylated polyacrylamide, and poly(2-acrylamide)-2-methylpropane sulfate; nonionic polymer flocculants such as polyacrylamide and polyethylene oxide; and amphoteric polymer flocculants such as copolymers of acrylamide, aminoalkyl methacrylate, and sodium acrylate.

[0040] Furthermore, the means by which the coagulant is added to the water to be treated supplied into the supply member 20 are not particularly limited. For example, the coagulant may be added upstream of the supply pipe 30. Furthermore, the sedimentation apparatus 2 may be equipped with a flow straightening member 200 according to the first modified example or a flow straightening member 300 according to the second modified example instead of the flow straightening member 100. [Explanation of Symbols]

[0041] 1,2...Sedimentation apparatus, 10...Sedimentation tank, 20...Supply member, 21...Opening, 30...Supply pipe, 40...Rake, 50...Shaft, 60...Distributor, 70...Chamber, 80...Nozzle (example of additive part), 90...Mixer, 100,200,300...Flow straightening member, 110...Cylindrical part, 111...Opposite surface, 120...Bottom, 121,221...Through hole, 130...Lid

Claims

1. A sedimentation tank for separating the solid and liquid components of the water to be treated, A supply member provided inside the sedimentation tank, which receives the water to be treated through an opening formed on its side and supplies the water to be treated to the sedimentation tank downwards, A supply pipe that supplies the water to be treated to the supply member in a direction intersecting the first direction, which is the direction of the center line of the supply member, A flow straightening member provided inside the supply member, which changes the flow of the water to be treated supplied from the supply pipe through the opening, Equipped with, The rectifying member has at least an opposing surface facing the opening so as to intersect with a second direction which is the centerline direction of the supply pipe, and a bottom portion provided below the opening so as to connect the opposing portion and the supply member, wherein the opposing portion and the bottom portion extend on both sides of the opposing surface in directions intersecting the first and second directions along the inner surface of the supply member. Precipitation treatment device.

2. The rectifying member has an arc shape when viewed in the first direction. The precipitation apparatus according to claim 1.

3. The rectifying member has a circular shape when viewed in the first direction. The precipitation apparatus according to claim 1.

4. The bottom portion has a through hole formed in the vertical direction. The precipitation apparatus according to claim 1.

5. The rectifying member has a cover portion provided above the opening. The precipitation apparatus according to claim 1.

6. The supply member further includes an additive section for adding chemicals inside the supply member. The precipitation apparatus according to claim 1.

Images