Method for removing fibrous impurities

Abstract

To easily capture fibrous impurities contained in sludge and easily remove the captured fibrous impurities.SOLUTION: There is provided a method for removing fibrous impurities in which sludge generated in a water treatment process of a sewage treatment plant is transported to a water channel 21 provided at least before a dewatering process and discharged into the water channel 21, and a plurality of capture rods 22 provided in the water channel 21 selectively captures fibrous impurities contained in the sludge that are to be removed, and removes an object that has been captured by the capture rods 22. The plurality of capture rods 22 extend upward from a bottom 210 of the water channel 21 and are arranged along a second direction A2 that intersects with a first direction A1 along a direction of travel of a fluid flowing through the water channel 21.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for removing fibrous impurities.

Background Art

[0002] In the field of sewage treatment, generally, various screens are used to remove impurities. In sludge pumps, underwater stirrers, piping of sludge dehydrators, etc. used in at least one of the digestion process and the dehydration process for treating sludge generated in the water treatment system, operational failures and malfunctions of equipment clogged by entanglement of hair, etc. frequently occur.

[0003] Hair, etc. can be separated by reducing the mesh width of the screen or using a special screen such as a mesh shape. However, impurities other than hair, particularly cellulose-based impurities that contribute to an increase in the amount of digestion gas generated in the digestion process and an improvement in dewaterability in the dehydration process, are also captured in large quantities by the screen.

[0004] Patent Document 1 discloses a rotary brush provided on the outlet side of a sludge supply pipe in a digestion tank using sewage treatment sludge as a fermentation liquid. The brush part of this rotary brush is arranged at a position where it comes into contact with the sludge supplied from the sludge supply pipe into the digestion tank. The brush part of the rotary brush is rotated by a driving device, and scum such as hair contained in the sludge is captured and removed by the rotary brush.

[0005] Patent Document 2 discloses a method for producing sludge compost from sludge generated in the activated sludge treatment of organic wastewater. In Patent Document 2, a step of concentrating sludge containing fibrous impurities such as hair, a step of removing the fibrous impurities from the concentrated sludge using a removing device, and a step of composting the sludge from which the fibrous impurities have been removed are obtained, and sludge compost is produced. The removing device is a device in which a filter through which fibrous impurities hardly permeate from the concentrated sludge and an impeller that rotates immediately before the filter are combined.

[0006] Patent Document 3 discloses a cord for capturing fibrous substances such as hair contained in sewage flowing through a circulation water channel such as an oxidation ditch. Part of this cord circulates while being immersed in the circulation water channel. The fibrous substances such as hair caught by the cord are decomposed and removed by being immersed in a decomposition liquid disposed outside the water channel.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] In Patent Document 1, when removing slag from the brush part of a rotating brush, a complicated operation of separating the drive device from the brush part and pulling up the brush part is required. For this reason, not only is the device itself expensive, but it also leads to an increase in management costs.

[0009] In Patent Document 2, in addition to the impeller rotating in the sludge where hair and the like are present, entanglement of fibrous contaminants such as hair also occurs in the filter. For this reason, in addition to regularly removing fibrous contaminants, depending on the entanglement situation, it is also necessary to disassemble the device for maintenance. Therefore, not only is the device itself expensive, but it also leads to an increase in maintenance costs. In Patent Document 3, although the cord captures fibrous contaminants such as hair, it cannot be applied to the removal of fibrous contaminants such as hair in a water channel without circulation.

[0010] An object of the present invention is to easily capture fibrous contaminants contained in sludge and easily remove the captured fibrous contaminants.

Means for Solving the Problems

[0011] In a method for removing fibrous contaminants according to an embodiment, sludge generated in a water treatment process of a sewage treatment plant is transferred to a water channel provided at least upstream of a dehydration process and flowed into the water channel. A plurality of capture rods provided in the water channel selectively capture objects to be removed among the fibrous contaminants contained in the sludge, and the objects to be removed captured by the plurality of capture rods are removed. The plurality of capture rods extend upward from the bottom of the water channel and are arranged along a second direction intersecting a first direction along the traveling direction of the fluid flowing through the water channel.

Advantages of the Invention

[0012] According to the present invention, it is possible to selectively capture and remove objects to be removed among the fibrous contaminants contained in sludge using capture rods.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] <Embodiment> Hereinafter, with reference to the drawings, a method for removing fibrous contaminants according to an embodiment will be described. In all the drawings for explaining the embodiment, the same or substantially the same configurations and elements are denoted by the same reference numerals. In addition, for the configurations and elements once described, repeated explanations will not be made in principle.

[0015] The method for removing fibrous contaminants according to this embodiment selectively removes contaminants to be removed having a predetermined size and shape from among fibrous contaminants such as hair and stringy substances contained in sludge generated from the water treatment system of a sewage treatment plant. According to a document (Proceedings of the 36th Sewage Research Presentation Meeting, pages 442 to 444, Morisawa et al. (1990)), as a result of examining the length of hair entangled in a sludge pump or an underwater agitator, it has been confirmed that hair having a length of 70 mm or more forms the core. Therefore, in this embodiment, the contaminants to be removed include at least one of hair and stringy substances having an elongated string shape with a length of 50 mm or more, preferably 70 mm or more, and a diameter of 30 μm or more.

[0016] <Overall configuration of the sludge treatment system> FIG. 1 is a schematic diagram showing the configuration of a sludge treatment system 100 to which the method for removing fibrous contaminants according to the embodiment is applied. The sludge treatment system 100 includes a removal water channel 2 in which a removal process is performed, a coagulation mixing tank 3 in which a coagulation process is performed, a concentration device 4 in which a concentration process is performed, a digestion tank 5 in which a digestion process is performed, and a dehydrator 6 in which a dehydration process is performed.

[0017] The sludge treatment system 100 is a system for treating sludge C. The sludge C treated by the sludge treatment system 100 is discharged from a water treatment system 1 provided in a sewage treatment facility or an industrial wastewater treatment facility. In the water treatment system 1, the pollutant components contained in the influent sewage A are converted into sludge C by microorganisms. That is, the pollutant components contained in the influent sewage A are removed. As a result, water (treated water) B from which the pollutant components have been removed and sludge C are discharged from the water treatment system 1.

[0018] The influent sewage A contains fibrous contaminants such as hair and stringy substances. Therefore, the sludge C discharged from the water treatment system 1 contains the above-mentioned fibrous contaminants. When the sludge treatment system 100 concentrates the sludge C discharged from the water treatment system 1 by the method described later, the fibrous contaminants contained in the sludge C are removed by the removal method described later. Note that the water treatment system 1 is not limited to those provided in a sewage treatment facility or an industrial wastewater treatment facility.

[0019] Figures 2(A) and 2(B) are diagrams schematically showing the removal channel 2, the coagulation mixing tank 3, and the concentration device 4 in the sludge treatment system 100 described above. Note that Figure 2(A) is a plan view of the device, and Figure 2(B) is a cross-sectional view of the device.

[0020] <Removal Channel / Removal Process> The removal channel 2 is connected to the water treatment system 1, and the above-mentioned object D to be removed among the fibrous impurities contained in the sludge C discharged from the water treatment system 1 is selectively removed and disposed of. On the other hand, the sludge E from which the object D to be removed has been removed from the sludge C is transferred to the coagulation mixing tank 3. Note that the details of the removal channel 2 will be described later.

[0021] <Coagulation Mixing Tank / Coagulation Process> The coagulation mixing tank 3 is connected to the removal channel 2, and the sludge E transferred (flowed in) from the removal channel 2 flows in. In the coagulation mixing tank 3, a coagulant F is added to the inflowing sludge E. The coagulant F is stored in a coagulant tank (not shown). A supply path for the coagulant F is formed by a pipe between the coagulant tank and the coagulation mixing tank 3, and a pump is provided on the supply path. However, the method and equipment for supplying the coagulant F to the coagulation mixing tank 3 are not limited to specific methods and equipment.

[0022] The coagulation mixing tank 3 has a drive device 31, a stirring shaft 32, stirring blades 33, and a coagulation mixing water tank 34. The drive device 31 drives the stirring blades 33 provided in the coagulation mixing water tank 34 by rotationally driving the stirring shaft 32. The sludge E to which the coagulant F has been added is stirred in the coagulation mixing water tank 34, and the solid components in the sludge E aggregate to form coagulation flocs G. Note that there are various products with different tank shapes, stirring blade shapes, etc. in the coagulation mixing tank 3, but as long as the desired coagulation flocs G are formed, the method and shape are not particularly limited. The formed coagulation flocs G are supplied to the concentration device 4.

[0023] <Concentration Device / Concentration Process> The thickening device 4 thickens the supplied agglomerated flocs G to the target concentration and separates them into thickened sludge I and thickened filtrate H. Note that there are various thickening methods by the thickening device 4, such as a screw method, a belt method, a drum method, etc. As long as the agglomerated flocs G can be thickened to the target concentration, the method is not particularly limited. The thickened sludge I is transferred to the digestion tank 5, and the thickened filtrate H is refluxed to the water treatment system 1.

[0024] <Digestion tank / Digestion process> The thickened sludge I separated by the thickening device 4 is transferred to the digestion tank 5 and stored. The digestion tank 5 is, for example, a metal tank having airtightness and corrosion resistance. Viewed from another perspective, in the digestion tank 5, a digestion process is performed in which the thickened sludge I separated by the thickening device 4 is digested in an anaerobic state with air and light blocked. In the digestion process, the thickened sludge I is heated, stirred, and circulated to a required temperature. The thickened sludge I is digested for 20 to 30 days under the above conditions. However, the digestion treatment is appropriately changed according to temperature conditions and the like.

[0025] Here, the thickened sludge I stored in the digestion tank 5 has been thickened by removing a certain amount of moisture by the thickening device 4. As a result, the higher the concentration of the thickened sludge I transferred to the digestion tank 5, the smaller the volume of the digestion tank 5 can be made, and the initial cost (construction cost) can be reduced. In addition, since the thickened sludge I in the digestion tank 5 can be heated, stirred, and circulated with less energy, the power of the stirrer, circulation pump, etc. is also reduced, and the running cost can also be reduced.

[0026] In the digestion process, digestion gas J is generated. More specifically, a part of the thickened sludge I stored in the digestion tank 5 is converted into methane gas, carbon dioxide, etc. The digestion gas J is used for power generation or for heating the thickened sludge I supplied into the digestion tank 5.

[0027] <Dehydrator / Dehydration process> When the digestion process is completed, the thickened sludge I is sent to the dehydrator 6 as digested sludge K. The dehydrator 6 removes moisture from the digested sludge K to form a dehydrated cake L. The dehydrated cake L is taken out of the dehydrator 6 and finally disposed of. In other words, the dehydrator 6 performs a dehydration process of removing moisture from the digested digested sludge K to form a dehydrated cake L.

[0028] Note that the digestion process may not be provided. In this case, the thickened sludge I thickened by the thickening device 4 is sent to the dehydrator 6 for dehydration without passing through the digestion tank 5. Even in such a case, an improvement in dehydration performance (for example, improvement in the water content of the dehydrated cake L, increase in the sludge treatment amount per unit time, etc.) can be expected compared to the case of dehydrating unthickened sludge.

[0029] As described above, the sludge C generated in the water treatment system 1 is transferred to the digestion tank 5 and the dehydrator 6, and the digestion process and the dehydration process are performed. Also, when the digestion process is not provided, the sludge C generated in the water treatment system 1 is transferred to the dehydrator 6 and the dehydration process is performed. In any of the processes, in the piping of the sludge pump, the underwater agitator, the sludge dehydrator, etc., operational failures or malfunctions of the equipment may occur due to entanglement and blockage of fibrous impurities such as hair. For this reason, in the present embodiment, the removal process performed in the removal water channel 2 is performed as a process prior to the digestion process. When the digestion process is not provided, the removal process is performed as a process prior to the dehydration process. In other words, the removal process performed in the removal water channel 2 is performed as a process at least prior to the dehydration process.

[0030] <Removal water channel> Details of the removal water channel 2 used in the removal process will be described. The removal water channel 2 includes a water channel 21, a capture rod 22, a removal plate 23, a rectifying plate 24, and a sludge supply pipe 25. The sludge C generated in the water treatment system 1 is supplied to the water channel 21 through the sludge supply pipe 25. The supplied sludge C flows in the water channel 21 along the traveling direction of the fluid (hereinafter referred to as the first direction) indicated by the arrow A1 in FIGS. 2(A) and 2(B) in a state where the generation of turbulent flow is suppressed by the rectifying plate 24.

[0031] When the flow velocity of the sludge C flowing through the water channel 21 is too high, the object D to be removed is less likely to get entangled with the capture rod 22 described later. Therefore, the flow velocity is set based on the results of experiments or the like to a velocity at which the object D to be removed is likely to get entangled with the capture rod 22 described later. Specifically, the flow velocity is set to 1 m / second or less, more preferably 0.6 m / second or less.

[0032] As described above, the removal step is performed at least in the stage before the dehydration step. Therefore, it can be said that the water channel 21 is a water channel provided at least in the stage before the dehydration step performed in the digestion tank 5.

[0033] The capture rod 22 and the removal plate 23 are arranged at the rear stage (downstream side) of the flow rectifying plate 24. The capture rod 22 is a member that captures the object D to be removed by entangling the object D to be removed among the fibrous impurities contained in the sludge C. The removal plate 23 is a member that removes the object D to be removed captured by entangling with the capture rod 22 to the outside of the water channel 21. Hereinafter, the capture rod 22 and the removal plate 23 will be described in detail.

[0034] <Capture rod> FIG. 3(A) is a plan view showing an enlarged view of the region R surrounded by the broken line shown in FIG. 2(A). FIG. 3(B) is a cross-sectional view taken along the line A-A shown in FIG. 3(A). The capture rod 22 is fixed to the bottom 210 of the water channel 21 and is formed in a columnar shape extending upward from the bottom 210. The diameter of the capture rod 22 is set to a size at which the object D to be removed is likely to get entangled based on the results of experiments or the like. Specifically, the diameter of the capture rod 22 is 1 mm or more and 10 mm or less, more preferably 3 mm or more and 7 mm or less. Note that the capture rod 22 is not limited to being formed in a columnar shape and may be formed in a prismatic shape. Also, the material of the capture rod 22 is not particularly limited.

[0035] A plurality of the capture rods 22 having the above-described shape are provided in the water channel 21. That is, the plurality of capture rods 22 are arranged in a direction along the first direction A1 in which the sludge C flows and in a direction along the second direction A2 that intersects the first direction A1. Specifically, a plurality of capture rod rows 220 each having a plurality of capture rods 22 along the second direction A2 are arranged along the first direction A1.

[0036] As shown in FIG. 3(A), the first capture rod row 221 has six capture rods 22, and the second capture rod row 222 has five capture rods 22. In each capture rod row 220, the interval between adjacent capture rods 22 along the second direction A2 is, for example, 5 mm or more and 100 mm or less, more preferably 10 mm or more and 50 mm or less. If the interval between the capture rods 22 is too wide, it becomes difficult for the object D to be removed to get entangled with the capture rods 22. Also, if the interval between the capture rods 22 is too narrow, a large amount of debris other than the object D to be removed will be captured, which may block the water channel 21. Note that the number of capture rods 22 included in each capture rod row 220 is not limited to the above number, and is determined according to the length of the water channel 21 along the second direction A2 and the interval between the capture rods 22.

[0037] The plurality of capture rods 22 included in the first capture rod row 221 and the plurality of capture rods 22 included in the second capture rod row 222 are arranged in a herringbone pattern. That is, the plurality of capture rods 22 included in the first capture rod row 221 and the plurality of capture rods 22 included in the second capture rod row 222 are arranged at non-overlapping positions along the first direction A1. Thereby, it becomes possible to entangle the object D that has passed between the capture rods 22 of the second capture rod row 222 with the capture rods 22 of the first capture rod row 221.

[0038] Note that the present invention is not limited to the case where two capture rod rows 220 are provided. For example, the second capture rod row 222 may not be provided, and only one capture rod row 220 may be provided. That is, a plurality of capture rods 22 may be arranged in a second direction that intersects the first direction A1. Alternatively, three or more capture rod rows 220 may be provided. Specifically, the capture rod row 220 is preferably one row or more and ten rows or less, more preferably two rows or more and five rows or less.

[0039] <Removal plate> The removal plate 23 is provided so as to be movable along the direction in which the capture rod 22 extends (hereinafter referred to as the extension direction A3) in the water channel 21. Note that the extension direction A3 may be perpendicular or not perpendicular to the bottom 210 of the water channel 21 as long as it is a direction from the bottom 210 of the water channel 21 upward.

[0040] As shown in FIGS. 3(A) and 3(B), the removal plate 23 is formed by a plate portion 231, an operation portion 232, and a connection portion 233. The plate portion 231 is a rectangular plate-shaped member having a long side along the second direction A2. A plurality of insertion holes 234 are formed in the plate portion 231 along the second direction A2. The diameter of the insertion hole 234 is slightly larger than the diameter of the capture rod 22. The capture rod 22 is inserted into the insertion hole 234. For this reason, the plurality of insertion holes 234 are formed on the plate portion 231 with the same interval as the above-described interval in which the capture rods 22 are arranged along the second direction A2.

[0041] The operation portion 232 is a handle portion that is operated by an operator when moving the removal plate 23 along the extension direction A3. The operation portions 232 are respectively provided at one end and the other end in the second direction A2 of the removal plate 23. The connection portion 233 is a member that connects the plate portion 231 and the operation portion 232, and is respectively provided at one end and the other end in the second direction A2 of the plate portion 231. The connection portion 233 is a plate-shaped member extending along the extension direction A3.

[0042] Since the removal plate 23 has the above structure, the removal plate 23 can be guided by the capture rod 22 inserted into the insertion hole 234 according to the operation of the operator and move along the extension direction A3. In the following description, the direction in which the removal plate 23 moves toward the bottom 210 of the water channel 21 may be referred to as downward, and the direction in which the removal plate 23 moves away from the bottom 210 may be referred to as upward.

[0043] <Method for removing object to be removed> With reference to FIGS. 4(A) to 4(C), a method for removing the object D to be removed using the capture rod 22 and the removal plate 23 will be described. FIGS. 4(A) to 4(C) are cross-sectional views taken along the line B-B of FIG. 3(A). FIG. 4(A) shows a state where the removal plate 23 is not being operated and the plate portion 231 is in contact with or close to the bottom 210 of the water channel 21 and is positioned above. At this time, the sludge C generated in the water treatment system 1 and transferred to the water channel 21 is flowing in the water channel 21 along the first direction A1. The sludge C contains the fibrous contaminants described above. Among these fibrous contaminants, the object D to be removed gets entangled with the capture rod 22. That is, the plurality of capture rods 22 provided in the water channel 21 selectively capture the object D to be removed among the fibrous contaminants contained in the sludge C. As a result, downstream of the capture rod 22, the sludge E from which the object D to be removed has been removed flows.

[0044] The object D to be removed captured by the capture rod 22 as described above is removed by the removal plate 23. Specifically, with the supply of the sludge C to the removal water channel 2 stopped, the removal plate 23 moves upward along the capture rod 22, and the object D to be removed entangled with the capture rod 22 is removed.

[0045] FIG. 4(B) shows a state where the removal plate 23 is moving upward. Specifically, when the operator grasps the operation portion 232 and performs an operation of pulling it upward, the removal plate 23 moves along the extending direction A3. As described above, the diameter of the insertion hole 234 formed in the plate portion 231 is slightly larger than the diameter of the capture rod 22. Therefore, as the removal plate 23 moves upward, the object D to be removed entangled with the capture rod 22 is peeled off from the capture rod 22 and is pulled upward from below by the plate portion 231. That is, the object D to be removed moves upward as the plate portion 231 moves upward.

[0046] FIG. 4(C) shows a state in which the removal plate 23 has moved further upward from the state shown in FIG. 4(B) and is separated from the capture rod 22. On the plate portion 231 of the removal plate 23 separated from the capture rod 22, the object D to be removed that has moved upward as the removal plate 23 moves upward is deposited. This object D to be removed is removed from the plate portion 231 and collected in a predetermined collection section. As a result, the object D to be removed is removed.

[0047] According to the above-described embodiment, at least one of the following operational effects can be obtained.

[0048] (1) The sludge C generated in the water treatment process of the sewage treatment plant is transferred to the water channel 21 provided at least in the stage before the dehydration stage and flowed into the water channel 21. The plurality of capture rods 22 provided in the water channel 21 selectively capture the object D to be removed among the fibrous contaminants contained in the sludge C, and the object D to be removed captured by the plurality of capture rods 22 is removed. The plurality of capture rods 22 extend upward from the bottom 210 of the water channel 21 and are arranged along a second direction A2 that intersects a first direction A1 along the traveling direction of the fluid flowing through the water channel 21. Thereby, with a simple configuration of the capture rod 22, it is possible to entangle and remove the fibrous contaminants, so that it is possible to suppress an increase in the cost of the apparatus and reduce the cost of maintenance and management.

[0049] Further, the capture rod 22 has a circular cross-section with a diameter of 1 mm or more and 10 mm or less, and among the fibrous contaminants, the object D to be removed, which is at least one of hair and string-like objects having a length of 50 mm or more and a diameter of 30 μm or more, is entangled with the capture rod 22. Thereby, among the fibrous contaminants, the object D to be removed, which is the main cause of entanglement and blockage in pipes such as sludge pumps, underwater agitators, and sludge dehydrators, can be selectively removed, so that it is possible to suppress the occurrence of operational failures of the equipment.

[0050] Further, the capture rods 22 are arranged at intervals of 5 mm or more and 50 mm or less along the second direction. Thereby, it is possible to suppress the object D to be removed from being entangled with the capture rods 22 and flowing through the water channel 21 downstream by passing between the capture rods 22, so that the occurrence of operational failures of each subsequent device and the like can be suppressed.

[0051] (2) In the water channel 21, a plurality of catching bar rows 220 having a plurality of catching bars 22 arranged along the second direction are arranged in a plurality along the first direction. Thereby, it becomes possible to catch the object D to be removed that has not been caught by the catching bars 22 of a certain catching bar row 220 with the catching bars 22 of a more downstream catching bar row 220. As a result, it is suppressed that the object D to be removed reaches each device in the subsequent stage and becomes entangled, causing an operation failure in the device.

[0052] (3) The catching bars 22 included in the first catching bar row 221 and the catching bars 22 included in the second catching bar row 222 among the plurality of catching bar rows 220 are arranged at non-overlapping positions along the first direction. Thereby, it is suppressed that the object D to be removed passes between the catching bars 22 and flows downstream in the water channel 21, and the occurrence of an operation failure of the device can be suppressed.

[0053] (4) A removal plate 23 provided for each catching bar row 220 and having an insertion hole 234 into which the catching bar 22 is inserted moves from the bottom 210 of the water channel 21 along the catching bar 22 with the catching bar 22 inserted into the insertion hole 234 to remove the object D to be removed caught by the catching bar 22. Thereby, with a simple configuration, the object D to be removed entangled with the catching bar 22 can be removed, so that an increase in the cost of the apparatus can be suppressed, and the object D to be removed can be removed by a short-time operation, making it possible to reduce the maintenance cost.

[0054] (5) The removal plate 23 is provided with an operation unit 232 for performing an operation of moving the removal plate 23 along the catching bar 22. Thereby, the object D to be removed can be removed with a simple configuration without power, so that an increase in the cost of the apparatus can be suppressed.

[0055] <First Modification Example> In the above-described embodiment, the removal plate 23 is moved by the operation of an operator, but the removal plate 23 may be moved in the vertical direction by a driving device. FIG. 5 is a diagram schematically showing a cross section of the capture rod 22, the removal plate 23, the driving device 26 for driving the removal plate 23, and the detection device 27 for detecting the position of the removal plate 23 in the first modification.

[0056] The driving device 26 includes a driving source 260 such as a motor, a rotating shaft 261, a gear 262, and a rack portion 263. The driving source 260 has, for example, a coil, a yoke, a magnet, etc., and rotates by electric power (current) supplied from a power supply unit (not shown). The rotation direction of the driving source 260 is reversed according to the direction of the current supplied to the coil. For example, when a current in a certain direction flows through the coil, the driving source 260 rotates clockwise, and when a current in the opposite direction flows through the coil, the driving source 260 rotates counterclockwise.

[0057] The rotating shaft 261 extends along a first direction A1 intersecting the extending direction A3, and the gear 262 is attached thereto. The rotating shaft 261 is rotationally driven by the rotation of the driving source 260. The gear 262 attached to the rotating shaft 261 rotates in response to the rotational drive of the rotating shaft 261. As described above, the rotation direction of the driving source 260 is reversed according to the direction of the current supplied. Therefore, the rotating shaft 261 and the gear 262 also have their rotation directions reversed according to the direction of the current supplied to the driving source 260. The gear 262 meshes with the rack portion 263.

[0058] The rack portion 263 is disposed on the side of the connection portion 233 of the removal plate 23 that faces the side wall surface of the water channel 21. The rack portion 263 is a member in which a plurality of teeth are arranged along the extending direction A3 and meshes with the gear 262. The rack portion 263 is a member that converts the rotational force into a linear moving force along the vertical direction when the gear 262 is driven as the driving source 260 rotates. As a result, a moving force along the vertical direction acts on the connection portion 233, and the removal plate 23 moves along the vertical direction (extending direction A3).

[0059] Here, the removal plate 23 can also be automatically stopped by a detection device 27 including a limit switch holding component 271 fixed to the water channel 21, a limit switch (lower) 272, and a limit switch (upper) 273. The limit switch holding component 271 fixed to the water channel 21 is provided with the limit switch (lower) 272 and the limit switch (upper) 273. When the driving device 26 moves the removal plate 23 upward and the limit switch (upper) 273 detects that the operation part 232 has reached the upper limit position, the driving device 26 automatically stops, and the removal plate 23 also automatically stops. Also, when the driving device 26 moves the removal plate 23 downward and the limit switch (lower) 272 detects that the operation part 232 has reached the lower limit position, the driving device 26 automatically stops, and the removal plate 23 also automatically stops.

[0060] Note that the configurations of the driving device 26 and the detection device 27 described above are merely examples and are not limited to the above configurations. The driving device 26 can have any configuration necessary to move the removal plate 23 in the vertical direction, and the detection device 27 can similarly have any configuration necessary to detect the position of the removal plate 23 that moves in the vertical direction by the driving device 26. Also, the capture rod 22 and the removal plate 23 have the same configuration as in the above-described embodiment.

[0061] According to the first modification example, in addition to the operational effects (1) to (4) obtained by the embodiment, the following operational effects can be obtained.

[0062] A driving device 26 and a detection device 27 for moving the removal plate 23 along the capture rod 22 are provided. Thereby, the removal object D entangled with the capture rod 22 can be automatically removed, improving convenience.

[0063] <Second Modification Example> In the embodiment, the capture rod 22 has been described as being fixed to the bottom 210 of the water channel 21. However, the capture rod 22 may be detachably provided on the bottom 210. In this case, a hole is formed in the bottom 210 at the position where the capture rod 22 is provided. The capture rod 22 is disposed in the water channel 21 by inserting the lower end portion of the capture rod 22 into this hole. Further, when removing the object D to be removed, the capture rod 22 may be pulled out from the above hole, and the object D entangled with the capture rod 22 may be removed. Alternatively, a female screw may be formed in the above hole, a male screw may be formed near the lower end portion of the capture rod 22, and the capture rod 22 may be detachably screwed to the hole. By providing the capture rod 22 detachably on the bottom 210, it becomes possible to remove and eliminate the object D entangled with the capture rod 22 without providing the removal plate 23.

[0064] According to the second modification, the same operational effects as the operational effects (1) to (3) obtained by the embodiment can be obtained.

[0065] In the above, various embodiments and modifications have been described, but the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

Explanation of reference numerals

[0066] 1 Water treatment system, 2 Removal waterway, 3 Coagulation mixing tank, 4 Concentration device, 5 Digestion tank, 6 Dewatering machine, 21 Waterway, 22 Capture rod, 23 Removal plate, 24 Rectifying plate, 25 Sludge supply pipe, 26 Driving device, 27 Detection device, 31 Driving device, 32 Stirring shaft, 33 Stirring blades, 34 Coagulation mixing water tank, 100 Sludge treatment system, 210 Bottom, 220 Capture rod array, 221 First capture rod array, 222 Second capture rod array, 231 Plate part, 232 Operation part, 233 Connection part, 234 Insertion hole, 260 Driving source, 261 Rotation shaft, 262 Gear, 263 Rack part, 271 Limit switch holding part, 272 Limit switch (lower), 273 Limit switch (upper), A Inflowing sewage, B Treated water, C Sludge, D Object to be removed, E Sludge, F Coagulant, G Coagulation flocs, H Concentrated filtrate, I Concentrated sludge, J Digested gas, K Digested sludge, L Dewatered cake

Claims

1. Transfer the sludge generated in the water treatment process of the sewage treatment plant to a water channel provided at least upstream of the dehydration process and let it flow into the water channel, Selectively capture the objects to be removed among the fibrous impurities contained in the sludge by a plurality of capture rods provided in the water channel, Remove the objects to be removed captured by the plurality of capture rods, The plurality of capture rods extend upward from the bottom of the water channel and are arranged along a second direction intersecting a first direction along the traveling direction of the fluid flowing through the water channel. A method for removing fibrous impurities.

2. In the method for removing fibrous impurities according to Claim 1, In the water channel, a plurality of capture rod rows having the plurality of capture rods arranged along the second direction are arranged in a plurality along the first direction. A method for removing fibrous impurities.

3. In the method for removing fibrous impurities according to Claim 2, Among the plurality of capture rod rows, the capture rods included in the first capture rod row and the capture rods included in the second capture rod row are arranged at non-overlapping positions along the first direction. A method for removing fibrous impurities.

4. In the method for removing fibrous impurities according to Claim 3, The cross section of each of the capture rods is a circle with a diameter of 1 mm or more and 10 mm or less. A method for removing fibrous impurities.

5. In the method for removing fibrous impurities according to Claim 4, The plurality of capture rods are arranged at intervals of 5 mm or more and 100 mm or less along the second direction. A method for removing fibrous impurities.

6. In the method for removing fibrous impurities according to Claim 2, A plate provided for each of the capture rod rows and having insertion holes into which the capture rods are inserted moves from the bottom of the water channel along the capture rods with the capture rods inserted into the insertion holes, and removes the objects to be removed captured by the capture rods from the capture rods. A method for removing fibrous impurities.

7. In the method for removing fibrous impurities according to Claim 6, The plate is provided with an operation part for performing an operation of moving the plate along the capture rods. A method for removing fibrous impurities.

8. In the method for removing fibrous impurities according to Claim 6, The plate is moved along the capture rods by a driving device. A method for removing fibrous impurities.

9. In the method for removing fibrous impurities according to Claim 5, The flow velocity of the fluid flowing through the water channel is 1 m / second or less. A method for removing fibrous impurities.

10. In the method for removing fibrous contaminants according to any one of claims 1 to 9, the object to be removed is at least one of hair and stringy materials among the fibrous contaminants, having a length of 50 mm or more and a diameter of 30 μm or more, and the method for removing fibrous contaminants.

Images