Scum peeling device, water conduit, and sedimentation pond

Abstract

Provided is a scum peeling device comprising: a pair of pipes that extend along a flow direction of raw water inside two side walls of a water conduit, have a plurality of openings at intervals in a length direction, and are provided so as to be positioned below scum; and a plurality of pressure fluid supply units that supply a pressure fluid from a pressure fluid supply source to the pipes, wherein the pipes are divided into a plurality of regions having a predetermined length along the flow direction of the raw water, the pressure fluid supply units are respectively connected to divided regions, and, by jetting the pressure fluid from the openings of the pipes, the scum is smoothly peeled off from the entire inner wall of the water conduit.

Description

Scum remover, conduit and settling tank

[0001] The present invention relates to a scum removal device installed in a conduit and a sedimentation basin of a sewage treatment plant, and a conduit and a sedimentation basin equipped with a scum removal device. This application claims priority based on Japanese Patent Application No. 2023-122979, filed on July 28, 2023, the contents of which are incorporated herein by reference.

[0002] A sewage treatment plant is equipped with a primary sedimentation tank, sometimes called a first sedimentation tank, which separates sedimentary substances in the sewage received at the plant by settling, and a final sedimentation tank, sometimes called a second sedimentation tank, which receives raw water that has been biologically treated from the primary sedimentation tank and separates activated sludge by settling. These sedimentation tanks are made up of multiple tanks lined up side by side. Raw water is distributed and supplied to each sedimentation tank from a single water conveyance conduit (sometimes called an "inlet conduit").

[0003] The raw water flowing through the conduit contains floating substances in addition to sedimentary substances due to its nature as sewage. As a result, scum, a collection of floating substances, forms on the water surface of the conduit. In the case of a conduit for a primary sedimentation basin, the scum is removed when the thickness of the formed scum layer reaches a predetermined thickness or when a predetermined treatment time has elapsed.

[0004] Scum is removed by discharging it into a scum pit (sometimes called a "drainage pit") located on the opposite side of the conduit from where raw water is supplied. This scum is discharged by opening a movable gate located between the conduit and the scum pit and pouring surface water containing the scum layer into the scum pit, but if the scum has solidified or is attached to the inner wall of the conduit, the scum cannot be discharged smoothly by the flow of surface water alone.

[0005] Therefore, the present applicant has previously proposed a water conduit that can efficiently discharge scum into a scum pit in Patent Document 1. The proposed water conduit is equipped with water injection nozzles that are provided above the scum and that spray pressurized water to push the scum toward the scum pit, injection nozzles that are provided in the water below the scum and that spray pressurized water to push the scum toward the scum pit, and a compressed air injection mechanism that is provided on the inner wall of the water conduit and that sprays compressed air along the inner wall to remove the scum from the inner wall.

[0006] The proposed conduit has the advantage that pressurized water is sprayed from above and below the scum to push the scum toward the scum pit, and the scum is peeled off from the inner wall, allowing the scum to be smoothly discharged into the scum pit.

[0007] International Publication No. 2022 / 123652

[0008] In the water conveyance conduit disclosed in Patent Document 1, scum is removed by entraining it with the flow of surface water and discharging it into a scum pit, so the shorter the entrainment time, the less water is required for entrainment. This reduction in entrained water directly leads to a reduction in the subsequent entrained water treatment costs, including electricity costs, so there has been a demand for a further reduction in the entrainment time.

[0009] In order to meet the above demand, the inventors have closely observed the movement of scum and found that if scum adheres to even a part of the inner wall of the main body of a water conduit, which is several tens of meters long, or if there are parts where the scum is not peeling off properly, the time required for the entire scum to be discharged will be longer.

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a scum removal device that can smoothly remove scum from the entire inner walls of a water conduit or a settling basin.

[0011] In order to achieve the above object, the scum removal device of the present invention is a scum removal device that removes scum adhering to the inner surface of the side wall of a conduit through which raw water flows, and comprises: a pair of pipes that extend inside the side wall of the conduit body in the direction of flow of the raw water, have a plurality of openings spaced apart in the lengthwise direction, and are located so as to be positioned below the scum; and a plurality of pressurized fluid supply units that supply pressurized fluid from a pressurized fluid supply source to the pipes, the pipes being divided into a plurality of regions of predetermined lengths along the direction of flow of the raw water, and a pressurized fluid supply unit is connected to each of the divided regions, and the pressurized fluid is sprayed from the openings of the pipes.

[0012] The pipe is divided into multiple regions of a predetermined length, and pressure fluid is supplied to each region, so that pressure fluid can be supplied evenly along the entire length of the pipe, and scum can be removed smoothly and reliably by the pressure fluid being ejected from the openings. It is also possible to supply the required pressure fluid to the pipe within the required divided region.

[0013] The pressure fluid is either compressed air, pressure water, or gas-liquid mixture pressure water.

[0014] In the scum removal device of the present invention, the pressurized fluid supply section preferably includes a pair of long pipe sections arranged parallel to and facing the pipe, and a plurality of connecting pipes spaced apart in the longitudinal direction and connecting the long pipe sections.

[0015] Since the pressurized fluid is supplied to the pipe through the long pipe section, the long pipe section functions as a header, and the pressurized fluid fills the long pipe section and is supplied to the pipe. This allows the pressurized fluid to be supplied evenly from each part of the long pipe section to the pipe. And because this long pipe section is provided at each pressurized fluid supply section, it becomes possible to supply the pressurized fluid evenly along the entire length of the pipe.

[0016] In the scum removal device of the present invention, a pair of short pipe sections may be provided at both ends of the long pipe section, connecting the ends of both the long pipe sections, and the long pipe section and the short pipe section may be connected in a loop shape in the pressure fluid supply section.

[0017] By supplying pressurized fluid to at least one point in the looped portion, the pressurized fluid can be supplied evenly to both pipes via the connecting pipe.

[0018] The scum remover of the present invention may further comprise a central connecting pipe that interconnects the long pipe portions at intermediate positions in the longitudinal direction, and the central connecting pipe is supplied with pressurized fluid from the pressurized fluid supply source.

[0019] Since the pressurized fluid is supplied to a midpoint in the longitudinal direction of the long pipe portion, the pressurized fluid can be supplied to the pipe evenly over the entire length of the long pipe portion.

[0020] In the scum remover of the present invention, the midpoint in the lengthwise direction of the long tubular portion may be a midpoint in the lengthwise direction of the long tubular portion, which allows for more uniform supply of scum.

[0021] The conduit of the present invention comprises the above-mentioned scum remover and a conduit body, the side walls being the side walls of the conduit body, and the conduit body being provided with a plurality of at least one of above-water nozzles that spray pressurized water from above the water surface to promote the flow of scum generated on the surface of the raw water downstream, and underwater nozzles that spray pressurized water from underwater to promote the flow of the scum downstream.

[0022] By injecting pressurized water from an above-water nozzle onto the scum floating and gathering on the water surface, if the scum has solidified on the water surface, it is broken down to make it easier to flow, and the scum is swept downstream as a whole, making it easy to discharge, and in combination with the action of the scum peeling device, the scum can be discharged reliably and smoothly.

[0023] In addition, pressurized water can be sprayed from underwater nozzles to flush scum floating on the water surface downstream from below the surface, making it easier to remove the scum.

[0024] In the conduit of the present invention, the conduit body is provided with a scum pit for discharging the scum on the water surface at the end position of the raw water flow direction, and an openable gate at a position on the side wall below the scum for supplying raw water to a settling tank.

[0025] Since most of the scum floating on the water surface can be discharged into a scum pit, the raw water from which the scum has been removed can be supplied to a settling tank, facilitating subsequent treatment.

[0026] The scum remover of the present invention ejects pressurized fluid from multiple openings of a pair of pipes to remove scum adhering to the inner walls, and supplies the pressurized fluid to each section of the pipe that is divided into predetermined lengths, thereby enabling the pressurized fluid to be supplied uniformly along the length of the pipes. It is also possible to supply the required pressurized fluid to the pipes in the required section.

[0027] Therefore, the entire scum is effectively removed, and the scum can be discharged smoothly into the scum pit in a short time, which contributes greatly to improving water quality and reduces the amount of water required to entrain the scum. This reduces the cost of treating the treated water associated with scum discharge, and also allows for a significant reduction in the amount of electricity used.

[0028] 4 is a plan view showing a conduit equipped with a scum removal device according to a first embodiment of the present invention and a part of a sedimentation basin connected to the conduit. FIG. 1 is a cross-sectional view taken along line A-A in FIG. 1, showing a state in which a movable gate is closed. FIG. 2 is a partial cross-sectional view taken along line A-A in FIG. 1, showing a state in which a movable gate is open. The pressurized fluid supply unit is omitted. FIG. 4 is an enlarged plan view of a portion of the scum removal device according to the first embodiment of the present invention. FIG. 5 is a partial enlarged view of a pipe and a discharge port member taken along line B-B in FIG. 4. FIG. 5 is an enlarged plan view similar to FIG. 4, showing a second embodiment of a pressurized fluid supply unit of a scum removal device according to the present invention. FIG. 6 is an enlarged plan view similar to FIG. 4, showing a third embodiment of a pressurized fluid supply unit of a scum removal device according to the present invention.

[0029] Hereinafter, embodiments of the present invention will be described. A conduit 1 in the first embodiment is used for a primary sedimentation basin and includes a conduit main body 2 and a scum pit 3 connected to the conduit main body 2. The conduit main body 2 is a long waterway with an open top, and is configured so that raw water consisting of sewage is supplied from one end (the right end in the example shown in Figure 1) in the longitudinal direction (the direction of raw water flow) (see arrow a).

[0030] The scum pit 3 is provided at the terminal end (the left end in the example shown in Figure 1) of the raw water flow direction (longitudinal direction of the conduit body 2) of the conduit body 2. A part of the wall X forming the scum pit 3 is shared with the wall forming the terminal end of the conduit body 2. The height of the upper wall surface 3a of this shared wall X is set to be lower than the water surface in the conduit body 2 (see Figure 2).

[0031] A movable gate 4 is provided on the side of the wall X facing the main conduit body 2, and is configured to control the flow of raw water and scum S from the main conduit body 2 into the scum pit 3. For ease of explanation, scum S that has grown to a certain thickness on the water surface is sometimes referred to as a "scum layer S."

[0032] The movable gate 4 includes a gate plate 4a and a drive mechanism 4b, and is closed as shown in Figure 2 when scum S is not being discharged from the main body 2 into the scum pit 3, and is open as shown in Figure 3 when scum S is being discharged from the conduit main body 2 into the scum pit 3. When the movable gate 4 is opened as shown in Figure 3, the surface water of the conduit main body 2, i.e., the raw water containing scum S, can be discharged into the scum pit 3.

[0033] The width of the gate plate 4a is slightly smaller than the width of the waterway of the water conduit main body 2, and its height is sufficiently greater than the difference between the position of the upper wall surface 3a and the water surface position within the water conduit main body 2. The drive mechanism 4b employs a well-known vertical movement mechanism such as a system consisting of a screw rod and a rotating nut, a rack and pinion system, or a hydraulic system so as to be able to move the gate plate 4a up and down.

[0034] When raw water (scum S) is not being discharged, the drive mechanism 4b raises the gate plate 4a so that the upper end of the gate plate 4a is sufficiently higher than the water surface in the conduit main body 2, thereby blocking communication between the scum pit 3 and the conduit main body 2, as shown in Fig. 2. When scum S is being discharged, the drive mechanism 4b lowers the gate plate 4a so that the upper end of the gate plate 4a is below the water surface in the conduit main body 2 and slightly below the bottom of the scum layer S formed in the conduit main body 2, as shown in Fig. 3, thereby establishing communication between the scum pit 3 and the conduit main body 2.

[0035] The scum pit 3 is provided with a scum discharge device 10 for discharging the accumulated scum S from the scum pit 3.

[0036] A plurality of settling tanks 6, which correspond to the primary settling tanks of a sewage treatment plant, are arranged side by side on the outside of one of a pair of side walls 5 in the longitudinal direction of the long channel that forms the main body 2 of the water conduit (the upper side wall in Figure 1).

[0037] A portion of the peripheral wall of each settling basin 6 is shared with the side wall 5 of the conduit main body 2, and an inlet 7 and an opening / closing gate 8 leading to each settling basin 6 are provided midway along the depth of the wall. The inside of the conduit main body 2 and each settling basin 6 are connected via each inlet 7.

[0038] When the opening / closing gate 8 of the inlet 7 is open, the raw water in the water conduit body 2 flows into the sedimentation basin 6 and can flow through the sedimentation basin 6 in a direction away from the side wall 5 (see arrow b in Figure 1). In the example shown in Figure 1, the sedimentation basin 6 is provided adjacent to the outside of one of the side walls 5 of the water conduit body 2, but it may also be provided adjacent to the outside of both side walls 5.

[0039] A pair of pipes 9, which constitute part of the scum remover 20, are installed inside both side walls 5 of the water conduit body 2, parallel to each side wall 5 and extend in the direction of the raw water flow. Each pipe 9 is made of a well-known pipe material such as steel or synthetic resin, and as shown in Figure 5, a number of discharge outlet members 21 are installed in a row at predetermined intervals along its length. The discharge outlet members 21 are made of synthetic resin such as fluororesin, and have a cup-like (bowl-like, bell-like, etc.) outer shape with an opening 22 at the bottom. The discharge outlet members 21 are fixed to the pipe 9 with their internal space communicating with the inside of the pipe 9, and the opening 22 is positioned vertically downward.

[0040] These pipes 9 are installed so as to be located below the scum layer S that forms within the conduit body 2. For example, if the conduit body 2 is set up so that scum S is discharged into the scum pit 3 from the conduit body 2 when it accumulates and grows to a certain thickness due to operation of the conduit 1, the pipes 9 are installed so as to be slightly below 10 cm from the water surface. The installation position of the pipes 9 varies depending on the sewage treatment plant in which the conduit body 2 is installed, but in any case, they are determined to be below the scum S that is formed.

[0041] The scum remover 20 includes the above-mentioned pipes 9 and a plurality of pressurized fluid supply units 23 that supply pressurized fluid such as compressed air, pressurized water, or gas-liquid mixed pressurized water to each pipe 9. Here, compressed air is used as an example of the pressurized fluid.

[0042] Each pipe 9 is installed along the length of the conduit main body 2 (along the direction of flow of raw water). The interior of the conduit main body 2 is divided into a plurality of regions (regions S1 to S3 in Figure 1) of predetermined lengths along the length. A pressurized fluid supply unit 23 is installed for each of the divided regions S1 to S3. Therefore, a plurality of pressurized fluid supply units 23 are installed within one conduit main body 2.

[0043] In the example shown in Figure 1, the interior of the water conduit body 2 is divided into three regions S1 to S3, and therefore three pressurized fluid supply units 23 are provided, respectively (however, the pressurized fluid supply units 23 are not shown in Figure 3). Each pressurized fluid supply unit 23 is connected to a pressurized fluid pipe 24 that supplies pressurized fluid from a pressure supply source (not shown) via a branch pipe 25. Each branch pipe 25 is provided with a flow rate adjustment valve 26 for controlling the flow rate to the respective pressurized fluid supply unit 23.

[0044] As shown in FIG. 4, each pressure fluid supply section 23 is configured to form a loop in plan view, with a pair of long pipe sections 27, 27 arranged parallel to each of a pair of pipes 9, 9, and a pair of short pipe sections 28, 28 connected to both ends of the pair of long pipe sections 27, 27.

[0045] At approximately the central positions of each of the pair of long pipe portions 27, 27, a central connecting pipe 29 that connects the two long pipe portions 27, 27 is connected. Therefore, the planar shape of each pressure fluid supply portion 23 assumes the shape of the Chinese character "日" (sun), θ (Greek letter), or a 7-segment display shape. At the central position in the length direction of the central connecting pipe 29, a branch pipe 25 from the pressure fluid pipe 24 is connected.

[0046] A plurality of connecting pipes 30 that connect between each of the pair of long pipe portions 27, 27 of the pressure fluid supply portion 23 and the pipes 9, 9 are provided at predetermined intervals from each other. Therefore, the pressure fluid from the pressure fluid source is supplied to each pressure fluid supply portion 23 through each branch pipe 25 from the pressure fluid pipe 24, and in each pressure fluid supply portion 23, it is supplied from the long pipe portion 27 to each pipe 9 through the connecting pipe 30.

[0047] Each pressure fluid supply portion 23, the pressure fluid pipe 24, and the branch pipe 25 are provided at a position above the water surface of the aqueduct main body 2. Although it is also possible to arrange these underwater, since it would obstruct the flow of raw water, it is preferable to arrange them above the water surface. In the figure, pipes 9 etc. indicated by broken lines show that they are provided underwater.

[0048] When pressure fluid (compressed air) is supplied into the pipes 9, 9, it is discharged as bubbles into the raw water from the downward opening 22 of the discharge port member 21. Then, the discharged bubbles rise along the inner surface of the side wall 5 and can peel off the scum adhering to the side wall 5.

[0049] Instead of the pipes 9 and the discharge port member 21, it is also possible to employ a pipe made of an elastic material such as natural rubber or synthetic rubber provided with a number of slits (openings) at intervals in the length direction, a steel pipe provided with a number of holes (openings) at intervals in the length direction, etc.

[0050] Furthermore, a plurality of water injection nozzles (above-water nozzles) 11 are provided in the aqueduct main body 2. The water injection nozzles 11 are provided at a plurality of locations slightly above the water surface in the aqueduct main body 2 so as to divide the length of the water flow direction in the aqueduct main body 2 at predetermined intervals, and a plurality of them are provided in the width direction of the aqueduct main body 2.

[0051] The water injection nozzles 11 may be omitted if the conduit 1 is used as a final settling basin. Whether or not to install the water injection nozzles 11 is determined by the properties of the scum generated in the conduit 1, and they may be omitted if the scum can be moved without water injection from the water injection nozzles 11 or if water injection would have a negative effect on the scum.

[0052] Water at a predetermined pressure is supplied to each water injection nozzle 11 via a pressurized water supply pipe 12. Treated water from a sewage treatment plant can be used as the water supplied to the water injection nozzles 11.

[0053] The water injection nozzles 11 are provided with their tip openings facing downstream of the water flow in the water conduit body 2, and also obliquely downward. Therefore, when pressurized water is injected from the water injection nozzles 11, the jetted water is supplied downstream against the scum S (scum layer S) that has formed in a layer on the water surface of the water conduit body 2, and promotes the flow of scum S toward the scum pit 3 (see Figure 3).

[0054] Furthermore, the conduit main body 2 is provided with a plurality of water injection nozzles (submerged nozzles) 13 that are disposed underwater. These water injection nozzles 13 are disposed slightly below the water surface in the conduit main body 2, and at predetermined intervals in the direction of water flow within the conduit main body 2. Furthermore, a plurality of water injection nozzles 13 (two in the example shown in Figure 1) are also provided at predetermined intervals from one another in the direction perpendicular to the direction of water flow within the conduit main body 2, i.e., across the width of the waterway.

[0055] Water at a predetermined pressure is also supplied to this water injection nozzle 13 through a pressurized water supply pipe 14. When pressurized water is supplied to the water injection nozzle 13 from the pressurized water supply pipe 14, the pressurized water is sprayed from an opening facing the scum pit 3, thereby promoting the flow of scum S that is trying to flow toward the scum pit 3 (see Figure 3). The water supplied to this water injection nozzle 13 can also be treated water from a sewage treatment plant.

[0056] In the following description, the water jet nozzle 11 installed above water will be referred to as an above-water nozzle, and the water jet nozzle 13 installed underwater will be referred to as an underwater nozzle.

[0057] A sewage treatment method including the scum discharge operation from the conduit 1 having the above-mentioned configuration will now be described.

[0058] When raw water (sewage) is supplied to the conduit main body 2, the raw water is distributed from the conduit main body 2 to each of the settling basins 6 through the inlets 7 provided corresponding to each of the settling basins 6. As the settling process takes place in each of the settling basins 6, scum S gradually forms on the water surface of the conduit main body 2. Figure 2 shows this state.

[0059] When the formation of scum S progresses to a certain extent in the water conduit body 2 and forms a layer, and the layer reaches a certain thickness, pressurized water is supplied to the submerged nozzle 13 and the above-water nozzle 11, which breaks up part of the scum layer S and pushes it downstream, and compressed air is supplied to the pipe 9. This starts the discharge of the scum S into the scum pit 3.

[0060] When pressurized water is supplied to the submerged nozzle 13, the pressurized water is sprayed from the submerged nozzle 13 so that the scum S flows toward the scum pit 3. The tip of the submerged nozzle 13 is formed slightly upward, which acts to lift the scum S slightly out of the water, causing the scum S to move. At the same time, pressurized water is also sprayed from the above-water nozzle 11 so that the scum S flows toward the scum pit 3.

[0061] When the scum discharge operation starts, compressed air is also ejected from the pipe 9, and the compressed air peels off the scum S adhering to the side wall 5. This allows the scum S to be discharged more smoothly and quickly into the scum pit 3. Figure 3 shows this state.

[0062] The ejection of compressed air from the pipe 9 will now be further explained.

[0063] Compressed air (pressurized fluid) is supplied to each pipe 9 provided along each side wall 5 from a pressurized fluid supply unit 23 via a connecting pipe 30. In this pressurized fluid supply unit 23, the pressurized fluid supplied from the branch pipes 25 to a central connecting pipe 29 is sent to each of the long pipe sections 27, 27. Since these long pipe sections 27, 27 are formed in a loop together with the short pipe sections 28, 28, the pressure inside the pressurized fluid supply unit 23 is maintained at a substantially uniform level. Therefore, compressed air at a substantially uniform pressure can be supplied to each of the pipes 9 connected to the pressurized fluid supply unit 23.

[0064] As a result, compressed air is ejected at a substantially uniform rate from the openings 22 of all of the discharge outlet members 21 provided near each side wall 5. Therefore, the scum S adhering to each side wall 5 can be effectively removed.

[0065] Furthermore, there are provided flow rate adjustment valves 26 that can individually adjust the amount of compressed air supplied to each pressurized fluid supply section 23. Therefore, for a portion of the conduit body 2 where scum S is likely to accumulate and has a strong adhesive force, such as the pressurized fluid supply section 23 provided at the end of the flow in the conduit body 2, the amount of compressed air supplied to the pressurized fluid supply section 23 can be increased by the flow rate adjustment valve 26, thereby enabling more effective removal of scum S from that portion.

[0066] Therefore, the supply flow rate of the pressurized fluid to each pressurized fluid supply section 23 can be individually controlled by the flow control valve 26, and the pressurized fluid can be appropriately supplied depending on the adhesion state of scum S, etc., and the scum S can be effectively removed.

[0067] When most of the scum S has been discharged from the water conduit body 2, the supply of pressurized water to the submerged nozzles 13 and the above-water nozzles 11 is stopped, and the supply of compressed air to the pipe 9 is also stopped. This completes the operation of discharging the scum S into the scum pit 3.

[0068] Although the above-mentioned operation of discharging the scum S into the scum pit 3 uses the submerged nozzle 13 and the above-water nozzle 11, it is also possible to use either one of them. For example, if the water conduit 1 is for a final settling tank, the above-water nozzle 11 may be omitted. Whether to use either one or both of them is determined depending on the properties and amount of the scum S to be generated.

[0069] 6 shows another embodiment (second embodiment) of the pressure fluid supply unit of the scum remover. This pressure fluid supply unit 41 has a different planar shape from the pressure fluid supply unit 23. In the pressure fluid supply unit 41, the same components as those in the pressure fluid supply unit 23 are designated by the same reference numerals.

[0070] This pressurized fluid supply unit 41 does not have the central connecting pipe 29 provided in the first embodiment, and is configured in a rectangular loop shape with a pair of long pipe sections 27 and a pair of short pipe sections 28. A branch pipe 25 from a pressurized fluid piping 24 (see FIG. 1, etc.) connected to a pressurized fluid supply source (not shown) is connected to one of the short pipe sections 28 (the short pipe section 28 on the right side in FIG. 6).

[0071] Therefore, in this embodiment, the pressurized fluid is supplied from the branch pipe 25 to the short pipe section 28, fills the loop-shaped pressurized fluid supply section 41 consisting of the short pipe section 28 and the long pipe section 27, is sent to the pipe 9 via each connecting pipe 30 of the long pipe section 27, and is discharged from the discharge port member 21 of each pipe 9.

[0072] This pressurized fluid supply part 41 is also formed in a loop shape and the pressure inside is kept approximately uniform, so that approximately uniform compressed air is ejected from all openings 22 of each pipe 9 connected to the pressurized fluid supply part 41. Therefore, scum S can be effectively removed from each side wall 5 corresponding to the long tube part 27 of the pressurized fluid supply part 41 (where each pipe is provided adjacent to it).

[0073] 7 shows yet another embodiment (third embodiment) of the pressurized fluid supply unit of the scum remover. This pressurized fluid supply unit 45 does not have a loop shape. That is, the pressurized fluid supply unit 45 does not have the short pipe sections 28, 28 of the first embodiment, but has a pair of long pipe sections 27, 27 and a central connecting pipe 29 connecting the long pipe sections 27, 27 at their longitudinal midpoints, with both ends of the long pipe sections 27, 27 closed. A branch pipe 25 is connected to the central connecting pipe 29 from a pressurized fluid piping 24 (see FIG. 1, etc.) that leads to a pressurized fluid supply source (not shown).

[0074] Therefore, in this embodiment, the pressurized fluid is supplied from the branch pipe 25 to the central connecting pipe 29, sent from the central connecting pipe 29 to each long pipe section 27, 27, sent from each long pipe section 27, 27 through the multiple connecting pipes 30 to each pipe 9, and discharged from the discharge member 21 of each pipe 9.

[0075] In addition, in the pressure fluid supply unit 45, the same components as those in the pressure fluid supply units 23 and 41 are given the same reference numerals.

[0076] The water conduit equipped with the scum removing device according to the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to the above-described embodiment, and design changes and the like are possible within the scope of the gist of the present invention.

[0077] For example, in the above example, the scum remover was applied to the water conduit of the primary sedimentation tank of a sewage treatment plant, but it can also be applied to the primary sedimentation tank or the final sedimentation tank of a sewage treatment plant. When applied to these sedimentation tanks, the pipes of the scum remover can be installed on the inner surface of both side walls of the sedimentation tank. Furthermore, these sedimentation tanks can also be equipped with either or both of the water injection nozzles (above-water nozzles) 11 and the water injection nozzles (under-water nozzles) 13.

[0078] Furthermore, although the example in which compressed air is used as the pressure fluid has been shown, it is also possible to use pressurized water or pressurized gas-liquid mixture water.

[0079] The pressure fluid supply unit may also have a planar shape other than that of the first embodiment (FIG. 4), the second embodiment (FIG. 6), or the third embodiment (FIG. 7). For example, one of the short pipe sections 28 in the pressure fluid supply unit 23 shown in FIG. 4 may be omitted, and the pressure fluid supply unit 23 may have a planar shape consisting of a pair of long pipe sections 27 and a short pipe section connecting the ends of the long pipe sections 27. In this case, one end of each of the long pipe sections 27 is closed, and the branch pipe is connected to the short pipe section.

[0080] The scum remover of the present invention can be suitably used in the water conveyance conduit, primary sedimentation tank, and final sedimentation tank of a sewage treatment plant.

[0081] REFERENCE SIGNS LIST 1 Conduit 2 Conduit body 3 Scum bit 4 Movable gate 6 Sedimentation basin 7 Inlet 8 Opening / closing gate 9 Pipe 10 Scum discharge device 11 Water injection nozzle (above water nozzle) 12 Pressurized water supply pipe 13 Water injection nozzle (underwater nozzle) 14 Pressurized water supply pipe 20 Scum remover 21 Discharge outlet member 22 Opening 23 Pressurized fluid supply section 24 Pressurized fluid piping 25 Branch pipe 26 Flow rate adjustment valve 27 Long pipe section 28 Short pipe section 29 Central connecting pipe 30 Connecting pipe 41 Pressurized fluid supply section 45 Pressurized fluid supply section

Claims

1. A scum removal device for removing scum adhering to the inner surface of a side wall of a conduit through which raw water flows, comprising: a pair of pipes extending inside the side wall of the conduit body in the direction of flow of the raw water, having a plurality of openings spaced apart in the length direction, and positioned so as to be located below the scum; and a plurality of pressurized fluid supply units for supplying pressurized fluid from a pressurized fluid supply source to the pipes, the pipes being divided into a plurality of regions of predetermined lengths along the direction of flow of the raw water, each of which is connected to a pressurized fluid supply unit, and the pressurized fluid is sprayed from the openings of the pipes.

2. A scum removal device as described in claim 1, characterized in that the pressurized fluid supply section comprises a pair of long tube sections arranged parallel to and facing the pipe, and a plurality of connecting tubes spaced apart in the longitudinal direction and connecting the long tube sections.

3. A scum remover as claimed in claim 2, characterized in that a pair of short pipe sections are provided at both ends of the long pipe section, connecting the ends of both the long pipe sections, and the long pipe section and the short pipe section are connected in a loop shape in the pressurized fluid supply section.

4. A scum removal device as described in claim 2, further comprising a central connecting pipe which connects the long tubular sections at intermediate positions in the longitudinal direction, and wherein the pressurized fluid from the pressurized fluid supply source is supplied to the central connecting pipe.

5. A scum remover according to claim 4, characterized in that the midway position in the longitudinal direction of the long tubular portion is a middle position in the longitudinal direction of the long tubular portion.

6. A conduit comprising a scum remover according to any one of claims 1 to 5 and a conduit body, characterized in that the side wall is a side wall of the conduit body, and the conduit body is provided with at least one of above-water nozzles which spray pressurized water from above the water to promote the flow of scum generated on the surface of the raw water downstream, and underwater nozzles which spray pressurized water from underwater to promote the flow of the scum downstream.

7. A water conduit as claimed in claim 6, characterized in that the water conduit body is provided with a scum pit for discharging scum on the water surface at the end position of the raw water flow direction, and an openable gate for supplying raw water to a settling tank at a position below the scum on the side wall.

8. A sedimentation basin equipped with a scum remover according to any one of claims 1 to 5, characterized in that the side wall is the side wall of a water conveyance conduit body.

Images