Air bubble supply facility

Abstract

To provide a bubble supply facility where electric energy consumption is suppressed.SOLUTION: A bubble supply facility 1 comprises: an aeration tank 2 to store a liquid; an agitator 3 to agitate the liquid stored in the aeration tank 2; a supply port 30 to supply a fine bubble liquid into the aeration tank 2; and a liquid sending device 5 to send the fine bubble liquid to the supply port 30. The agitator 3 forms the circulation flow of the liquid having a downward flow in the aeration tank 2. The supply port 30 supplies the fine bubble liquid downward along the circulation flow.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an air bubble supply facility that supplies air bubbles to stored liquid. [Background technology]

[0002] In wastewater treatment plants that treat wastewater such as sewage and rainwater, aerobic biological treatment is performed to remove nitrogen, phosphorus, and the like from the wastewater. The aerobic biological treatment is performed in an air bubble supply facility equipped with an aeration tank that stores wastewater. In this air bubble supply facility, an air diffuser is installed at the bottom of the aeration tank, and air is sprayed from the air diffuser into the aeration tank as fine bubbles, and the liquid is stirred by the upward force of the bubbles, thereby dissolving oxygen in the liquid stored in the aeration tank. In addition to wastewater treatment plants, air bubble supply facilities equipped with an air diffuser are also used in aquaculture plants that cultivate aquatic organisms such as fish, for example, in which air bubbles are sprayed from the air diffuser to stir the water, thereby dissolving oxygen required for aquatic organisms in water or seawater (see, for example, Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-23936 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the air bubble supply facility described in Patent Document 1, air must be sent against water pressure to the air diffuser at the bottom of the tank, and the sent air must be ejected as air bubbles from multiple small holes in the air diffuser. In addition, the amount of oxygen dissolved in wastewater or water is usually only about 10 to 30% of the oxygen contained in the bubbles ejected from the air diffuser, so a large amount of air bubbles must be ejected from the air diffuser. In addition, since the upward force of the air bubbles ejected from the air diffuser is used to agitate the wastewater or water, it is necessary to eject more air bubbles than necessary even when the dissolved oxygen concentration (DO value) is high and no air bubble supply is required. Furthermore, in order to prevent clogging of the air bubble ejection port of the air diffuser, air bubbles are constantly ejected to remove sludge and garbage near the air bubble ejection port. For these reasons, a large pump is required to send a large amount of air with a strong force to the bottom of the tank, and there is a problem that a large amount of electricity is consumed to drive the large pump continuously for a long time.

[0005] In view of the above circumstances, an object of the present invention is to provide an air bubble supply facility that reduces power consumption. [Means for solving the problem]

[0006] The air bubble supply facility of the present invention that solves the above-mentioned object includes a storage tank for storing a liquid containing a viscous material or a solid material, A stirring device that stirs the liquid stored in the storage tank; A supply port for supplying fine bubble liquid to the storage tank; a liquid delivery device that delivers the fine bubble liquid to the supply port, The stirring device is The rotor includes a blade disposed in a horizontally open area, and a shaft having a lower end portion to which the blade is fixed and which rotates the blade, A circulating flow of liquid having a downward flow is formed in the storage tank, The supply port is A horizontally open area is formed at the lower end of the shaft. The fine bubble liquid is supplied downward along the circulating flow. do.

[0007] In this air bubble supply facility, a concentration sensor for detecting a concentration of dissolved oxygen contained in the liquid stored in the storage tank; Depending on the dissolved oxygen concentration detected by the concentration sensor,A supply amount adjusting means for adjusting the supply amount of the fine bubble liquid supplied from the supply port. and The device may include: Effect of the Invention

[0008] According to the present invention, it is possible to provide an air bubble supply facility that reduces power consumption. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic plan view of an air bubble supply facility according to one embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view of the air bubble supply facility shown in FIG. 1 along the line AA. [Diagram 3] FIG. 3(a) is a plan view showing a first modified example of the stirring device shown in FIG. 1 and FIG. 2, and (b) is a front view of the stirring device shown in (a). [Figure 4] FIG. 3(a) is a plan view showing a second modified example of the stirring device shown in FIG. 1 and FIG. 2, and (b) is a front view of the stirring device shown in (a). [Diagram 5] FIG. 3(a) is a plan view showing a third modified example of the stirring device shown in FIG. 1 and FIG. 2, and (b) is a front view of the stirring device shown in (a). [Figure 6] 1 and 2, and FIG. 5(b) is a BB cross-sectional view of the agitator shown in FIG. [Figure 7] FIG. 1(a) is a plan view showing a fifth modified example of the mixer shown in FIGS. 1 and 2, and FIG. 1(b) is a CC sectional view of the mixer shown in FIG. [Figure 8] 5 is a cross-sectional view similar to FIG. 2 showing an air bubble supply facility according to a second embodiment. [Figure 9] 8, showing a bubble supply facility according to a modified example of the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The air bubble supply facility used in the description of one embodiment of the present invention is an air bubble supply facility that is installed in a wastewater treatment plant and performs aerobic biological treatment to remove nitrogen, phosphorus, etc. from wastewater.

[0011] FIG. 1 is a schematic plan view of an air bubble supply facility corresponding to one embodiment of the present invention.

[0012] As shown in FIG. 1, the air bubble supply facility 1 of this embodiment includes an aeration tank 2, an agitator 3, a liquid feeder 5, a concentration sensor 6, and a control device 7. The air bubble supply facility 1 is a wastewater treatment facility that performs biological treatment on wastewater from which contaminants such as sand have been removed in a wastewater treatment plant. Wastewater such as sewage and rainwater that has been treated in a grit basin and a primary sedimentation basin (not shown) flows into the aeration tank 2. The aeration tank 2 is a tank that receives and stores the inflowing wastewater and is rectangular in plan view. The aeration tank 2 corresponds to an example of a storage tank, and the wastewater received by the aeration tank 2 corresponds to an example of a liquid. In the aeration tank 2, activated sludge containing a large amount of aerobic microorganisms and fine bubble liquid are supplied, and aerobic biological treatment is performed by mixing them with the wastewater. The wastewater that has been biologically treated in the aeration tank 2 is sent to a final sedimentation tank (not shown). An anaerobic tank for performing anaerobic biological treatment may be provided upstream of the aeration tank 2, and multiple anaerobic tanks and multiple aeration tanks 2 may be arranged alternately. The agitator 3 is disposed in the center of the aeration tank 2 in a plan view.

[0013] FIG. 2 is a cross-sectional view taken along line AA of the air bubble supply facility shown in FIG.

[0014] As shown in FIG. 2, the agitator 3 is a propeller-type water flow generating device equipped with two blades 31, 31, a shaft 32, and a motor 33. The agitator 3 may have three or more blades 31. The blade 31 is disposed in the aeration tank 2 at a height position approximately halfway between the water surface WL of the wastewater stored in the aeration tank 2 and the tank bottom surface 2a of the aeration tank 2. The water surface WL may vary slightly depending on the amount of wastewater flowing into the aeration tank 2. The blade 31 is disposed at a position where it is always submerged in water regardless of fluctuations in the water level. The blade 31 rotates as the motor 33 rotates. The motor 33 is controlled by the control device 7. The rotation speed of the blade 31 is appropriately set in the range of 10 to 60 RPM according to the volume, shape, etc. of the aeration tank 2. As the blade 31 rotates, a downward flow of wastewater is generated near the blade 31. The rotation of the blades 31 creates a circulating flow that flows downward in the central part of the aeration tank 2 in a plan view and upward in the peripheral part of the aeration tank 2 in a plan view. The circulating flow circulates within the aeration tank 2 at a flow rate of 0.1 m / sec or more. The wastewater stored in the aeration tank 2, the activated sludge supplied to the aeration tank 2, and the fine bubble liquid supplied to the aeration tank 2 are agitated by the circulating flow. Note that the blades 31 may be rotated in the reverse direction to create an upward flow near the blades 31, or the blades 31 may be turned to the side to create a lateral flow near the blades 31.

[0015] The shaft 32 is a tube with an open upper end and a lower end, and an internal flow path 32a is formed inside the shaft connecting the upper and lower end openings. The opening at the lower end of the shaft 32 is the supply port 30 for the fine bubble liquid. The supply port 30 opens downward and discharges the fine bubble liquid downward. In FIG. 2, the discharge direction of the fine bubble liquid is indicated by a straight arrow. The shaft 32 is supported by a bearing (not shown) so as to be rotatable in the aeration tank 2. A rotary joint 321 is connected to the upper end of the shaft 32. A boss portion 311 is formed on the rotation center side of the blade 31, and the blade 31 is fixed to the lower end of the shaft 32 by this boss portion 311. The blade 31 and the shaft 32 in this embodiment correspond to an example of a rotating part and also correspond to an example of a moving part. In this embodiment, the height position of the lower end of the blade 31 and the height position of the lower end of the boss portion 311 are the same. However, the height position of the lower end of the blade 31 and the height position of the lower end of the boss portion 311 may be different.

[0016] A driven pulley 322 is fixed to the shaft 32 slightly below the rotary joint 321. A driving pulley 332 is fixed to the lower end of an output shaft 331 of the motor 33. The driven pulley 322 and the driving pulley 332 are connected by a V-belt 333. By driving the motor 33, the shaft 32 rotates at approximately the same rotation speed as the motor 33. The motor 33 and the rotary joint 321 are fixed above the aeration tank 2 by a fixing device (not shown).

[0017] The liquid delivery device 5 includes a liquid tank 50, a pump 51, a bubble liquid delivery pipe 52, and a bubble liquid generating device 53. The pump 51 is disposed in the liquid tank 50 and pumps up and delivers the water stored in the liquid tank 50. A predetermined amount of water is always maintained in the liquid tank 50 by supplying water pumped up from a final settling tank (not shown). Water from the water supply may be supplied to the liquid tank 50. The bubble liquid delivery pipe 52 is a pipe connected at one end to the pump 51 and at the other end to a rotary joint 321. In addition, in FIG. 1 and FIG. 2, the bubble liquid delivery pipe 52 is simplified and shown only by a solid line. The water pumped up by the pump 51 is delivered to the supply port 30 via the bubble liquid delivery pipe 52, the rotary joint 321, and the shaft inner flow path 32a, and is discharged from the supply port 30 to the aeration tank 2. As described above, the shaft 32 rotates when the motor 33 is driven, but since the bubble liquid delivery pipe 52 is connected to the shaft 32 via the rotary joint 321, it does not rotate regardless of the rotation of the shaft 32.

[0018] The bubble liquid generator 53 is installed in the middle of the bubble liquid delivery pipe 52. The bubble liquid generator 53 is a device that generates fine bubble liquid by a known swirling liquid flow method (see, for example, Japanese Patent No. 6169749). However, fine bubble liquid may be generated by other methods such as pressurized dissolution. The fine bubble liquid is a liquid containing fine bubbles of 100 μm or less. The fine bubble liquid may be a liquid containing microbubbles, which are bubbles with a diameter of more than 1 μm and 100 μm or less, or a liquid containing ultrafine bubbles, which are bubbles with a diameter of 1 μm or less. Furthermore, the fine bubble liquid may be a liquid containing both microbubbles and ultrafine bubbles. The water sucked up by the pump 51 is turned into fine bubble liquid by the bubble liquid generator 53 and supplied to the aeration tank 2 from the supply port 30. The pump 51 is driven intermittently according to commands from the control device 7. The control device 7 adjusts the supply amount of fine bubble liquid supplied from the supply port 30 to the aeration tank 2 by intermittently driving the pump 51. This control device 7 corresponds to an example of a supply amount adjusting means. Note that the pump 51 in this embodiment has a fixed amount of water suction, but a pump 51 that can adjust the amount of water suction may be used, and the suction amount may be controlled by the control device 7.

[0019] The concentration sensor 6 is disposed in the aeration tank 2. This concentration sensor 6 is a sensor that detects the concentration of dissolved oxygen contained in the wastewater stored in the aeration tank 2. The concentration sensor 6 is disposed at a height position approximately halfway between the water surface WL of the wastewater stored in the aeration tank 2 and the tank bottom surface 2a of the aeration tank 2, and is always submerged in water regardless of fluctuations in the water surface WL. The dissolved oxygen concentration detected by the concentration sensor 6 is input to the control device 7. In FIG. 2, a signal line connecting the concentration sensor 6 and the control device 7, a control line connecting the control device 7 and the motor 33, and a control line connecting the control device 7 and the pump 51 are indicated by dashed lines.

[0020] Next, the operation of the air bubble supply facility 1 will be described. The control device 7 constantly drives the motor 33 of the agitator 3 to rotate the blades 31 and the shaft 32, except for special cases such as maintenance. The control device 7 also controls the drive of the pump 51 according to the dissolved oxygen concentration detected by the concentration sensor 6. The control device 7 may be incorporated in the pump 51 and control only the drive of the pump 51. In this case, a separate control device may be provided for the motor 33. Alternatively, the control device 7 may be a centralized control device that controls devices installed in other facilities installed in the sewage treatment plant in addition to devices installed in the air bubble supply facility 1. If the dissolved oxygen concentration input to the control device 7 from the concentration sensor 6 is higher than 2.0 mg / L, the control device 7 stops the pump 51 and reduces the supply amount of fine bubble liquid to the aeration tank 2 to zero. If the dissolved oxygen concentration is 2.0 mg / L or less, the control device 7 drives the pump 51 so that the dissolved oxygen concentration approaches 2.0 mg / L. The target value of the dissolved oxygen concentration may be appropriately set depending on the size of the aeration tank 2, the amount of activated sludge supplied to the aeration tank 2, the concentrations of nitrogen and phosphorus contained in the wastewater, etc. When the pump 51 capable of adjusting the suction amount is used, the control device 7 may adjust the suction amount of the pump 51 depending on the dissolved oxygen concentration.

[0021] According to this embodiment, the pump 51 is controlled according to the dissolved oxygen concentration to adjust the supply amount of the fine bubble liquid to the aeration tank 2, so that the amount of oxygen necessary for aerobic biological treatment can be secured in the wastewater. In addition, since the fine bubble liquid containing the fine bubbles, which are floating bubbles, is supplied, oxygen can be efficiently dissolved in the wastewater. As a result, the dissolved oxygen concentration is likely to increase, so that the supply amount of the fine bubble liquid can be adjusted by intermittently operating the pump 51. Then, by stopping the pump 51 when the dissolved oxygen concentration in the wastewater stored in the aeration tank 2 exceeds the required concentration value, the power consumption of the pump 51 can be suppressed. In addition, when the pump 51 with an adjustable suction amount is used, the suction amount of the pump 51 may be reduced when the dissolved oxygen concentration is close to the target value, and the pump 51 may be stopped or the suction amount may be made very small when the dissolved oxygen concentration exceeds the target value. In addition, since the supply port 30 of the fine bubble liquid is formed on the rotating shaft 32, sludge and the like are less likely to remain in the supply port 30, and as a result, clogging of the supply port 30 can be suppressed. Furthermore, since the supply port 30 opens downward, it is possible to prevent the supply port 30 from being blocked and clogged by viscous matter such as sludge or solid matter that settles from above. In addition, since the supply port 30 is arranged near the blades 31, the stirring performance of the fine bubble liquid is improved. Furthermore, when an aeration device is used, the nozzle needs to be small to generate fine bubbles, but since fine bubble liquid is supplied, clogging can be suppressed by making the supply port 30 large. Even if the supply port 30 is clogged, the fine bubble liquid can easily push out the obstructing matter such as sludge that causes clogging by sending the fine bubble liquid to the supply port 30. In addition, since the surface area of ​​fine bubbles is larger relative to the volume than general air bubbles, aerobic biological treatment can be performed efficiently. As a result, a high biological treatment capacity can be obtained even if each component of the air bubble supply facility 1, such as the aeration tank 2, is made smaller. By making it smaller, the power required to drive each component can be suppressed. In addition, by making it smaller, the land required to construct the air bubble supply facility 1 can be made smaller.

[0022] Next, a modified example of this embodiment will be described. In the following description, components having the same names as components described so far will be denoted by the same reference numerals used so far, and duplicate descriptions may be omitted.

[0023] Fig. 3(a) is a plan view showing a first modified example of the stirring device shown in Fig. 1 and Fig. 2, and Fig. 3(b) is a front view of the stirring device shown in Fig. 3(a). In Fig. 3(a) and Fig. 3(b), the motor 33 is omitted.

[0024] As shown in FIG. 3(a), the agitator 3 of the first modification is different from the agitator 3 shown in FIG. 1 and FIG. 2 in that the blade 31 is provided with a supply port 30. The supply port 30 is formed at the tip of each of the two blades 31. The supply port 30 is formed at the center of the blade 31 in the height direction on the side opposite to the rotation direction of the blade 31. In FIG. 3(a), the rotation direction of the blade 31 is indicated by a curved arrow. That is, the blade 31 rotates clockwise in FIG. 3(a). As shown in FIG. 3(b), the blade 31 has an in-blade flow path 31a formed in the blade 31, which is connected to the in-shaft flow path 32a and continues to the supply port 30. The fine bubble liquid sucked up by the pump 51 (see FIG. 2) and sent to the in-shaft flow path 32a passes through the in-blade flow path 31a and is discharged from the supply port 30 into the aeration tank 2 (see FIG. 2). 3(a) and 3(b), the inner-shaft flow passage 32a and the inner-blade flow passage 31a are indicated by thin chain lines, respectively. As shown in FIG. 3(b), the lower end of the shaft 32 is closed.

[0025] In the agitator 3 of the first modification, the supply port 30 opens at the tip of the blade 31 in a direction inclined obliquely upward along the side shape of the blade 31. As shown in FIG. 3(a), the supply port 30 discharges the fine bubble liquid in the opposite direction to the rotation direction of the blade 31. In FIG. 3(a), the discharge direction of the fine bubble liquid is indicated by a straight arrow. In the agitator 3 of this modification, since the supply port 30 faces the opposite direction to the rotation direction of the blade 31, a force is applied to the fine bubble liquid in the blade inner flow path 31a by discharging it from the supply port 30 as the blade 31 rotates. In addition, a centrifugal force caused by the rotation of the blade 31 also applies a force toward the supply port 30 to the fine bubble liquid in the blade inner flow path 31a. These forces allow the fine bubble liquid to be discharged from the supply port even if the water suction force of the pump 51 is small. Therefore, the power of the pump 51 can be further reduced. In addition, since the supply port 30 is formed on the side opposite to the direction of rotation of the blades 31, sludge and the like in the wastewater is less likely to enter the supply port 30 when the blades 31 are rotating.

[0026] Next, a description will be given of a second modified example of the agitator 3. In the description of this second modified example, differences from the first modified example will be mainly described, and descriptions overlapping with the first modified example may be omitted.

[0027] Fig. 4(a) is a plan view showing a second modified example of the stirring device shown in Fig. 1 and Fig. 2, and Fig. 4(b) is a front view of the stirring device shown in Fig. 4(a). In Fig. 4(a) and Fig. 4(b), the motor 33 is also omitted.

[0028] As shown in FIG. 4(a) and FIG. 4(b), the agitator 3 of the second modification is different from the agitator 3 shown in FIG. 3 in that the blade 31 is provided with a plurality of supply ports 30, 30,.... In the second modification, as in the first modification, the blade 31 rotates clockwise in FIG. 4(a). The supply ports 30 are formed on the side surface opposite to the rotation direction of the blade 31, in the center portion of the blade 31 in the height direction, five of them for each blade 31. The number of the supply ports 30 may be more than five or less than five. The supply ports 30 open in a direction inclined obliquely upward along the side shape of the blade 31. As shown in FIG. 4(a), the blade inner flow passage 31a formed in the blade 31 has a plurality of blade inner branch flow passages 31b, 31b.... that branch off to the respective supply ports 30, 30,....

[0029] The fine bubble liquid is sucked up by the pump 51 (see FIG. 2) and sent to the inner-shaft flow path 32a, passes through the inner-blade flow path 31a and the inner-blade branch flow path 31b, and is discharged from each supply port 30 into the aeration tank 2 (see FIG. 2).

[0030] Each supply port 30 discharges the fine bubble liquid in the opposite direction to the rotation direction of the blade 31. In FIG. 4(a), the discharge direction of the fine bubble liquid is indicated by a straight arrow. In this second modified example, since the supply port 30 faces in the opposite direction to the rotation direction of the blade 31, a force is applied to the fine bubble liquid in the blade inner flow path 31a by the rotation of the blade 31, which causes the fine bubble liquid to be discharged from the supply port 30. In addition, the centrifugal force caused by the rotation of the blade 31 also applies a force toward the supply port 30 to the fine bubble liquid in the blade inner flow path 31a. Furthermore, since there are multiple supply ports 30 for each blade 31, there is little resistance when discharging the fine bubble liquid. As a result, the fine bubble liquid can be discharged from the supply port even if the water suction force of the pump 51 is small. Therefore, the power of the pump 51 can be further reduced. In addition, since each supply port 30 is formed on the side opposite to the rotation direction of the blade 31, sludge in the sewage is less likely to enter the supply port 30 when the blade 31 is rotating.

[0031] Next, a description will be given of a third modified example of the agitator 3. In the description of the third modified example, differences from the second modified example will be mainly described, and descriptions overlapping with the second modified example will be omitted in some cases.

[0032] Fig. 5(a) is a plan view showing a third modified example of the stirring device shown in Fig. 1 and Fig. 2, and Fig. 5(b) is a front view of the stirring device shown in Fig. 5(a). In Fig. 5(a) and Fig. 5(b), the motor 33 is also omitted.

[0033] As shown in Fig. 5(a) and Fig. 5(b), the agitator 3 of the third modified example is different from the agitator 3 shown in Fig. 4 in that a plurality of supply ports 30, 30, ... are provided at the lower end portion of the blade 31. As in the second modified example, the blade 31 of the third modified example rotates clockwise in Fig. 5(a). The supply ports 30 are formed on the side opposite to the rotation direction of the blade 31, at the lower end portion of the blade 31, five supply ports 30 for each blade 31. The number of supply ports 30 may be more than five or less than five. The lower end portion of the blade 31 is formed on a vertical surface, and the plurality of supply ports 30, 30, ... open sideways toward the horizontal direction.

[0034] Each supply port 30 discharges the fine bubble liquid in the opposite direction to the rotation direction of the blade 31. In FIG. 5(a), the discharge direction of the fine bubble liquid is indicated by a straight arrow. In this third modified example, since the supply port 30 faces in the opposite direction to the rotation direction of the blade 31, a force is applied to the fine bubble liquid in the blade inner flow path 31a by the rotation of the blade 31, which causes the fine bubble liquid to be discharged from the supply port 30. In addition, the centrifugal force caused by the rotation of the blade 31 also applies a force toward the supply port 30 to the fine bubble liquid in the blade inner flow path 31a. Furthermore, since there are multiple supply ports 30 for each blade 31, there is little resistance when discharging the fine bubble liquid. As a result, the fine bubble liquid can be discharged from the supply port even if the water suction force of the pump 51 is small. Therefore, the power of the pump 51 can be further reduced. In addition, since each supply port 30 is formed on the side opposite to the rotation direction of the blade 31, sludge in the sewage is less likely to enter the supply port 30 when the blade 31 is rotating. Furthermore, in the agitator 3 of the third modified example, the supply port 30 opens sideways, so that even if viscous matter such as sludge or solid matter settles from above, the viscous matter or solid matter will not enter the supply port 30. This can further reduce the risk of the supply port 30 being blocked.

[0035] Next, a fourth modified example of the stirring device 3 will be described. In the description of this fourth modified example, differences from the stirring device 3 shown in Figures 1 and 2 will be described, and descriptions overlapping with the description of the stirring device 3 shown in Figures 1 and 2 may be omitted.

[0036] Fig. 6(a) is a front view showing a fourth modified example of the stirring device shown in Fig. 1 and Fig. 2, and Fig. 6(b) is a BB cross-sectional view of the stirring device shown in Fig. 6(a). In Fig. 6(a) as well, the motor 33 is omitted.

[0037] As shown in FIG. 6(a), the agitator 3 of the fourth modified example is different from the agitator 3 shown in FIG. 1 and FIG. 2 in that two supply pipes 34, 34 are fixed to the shaft 32, and the supply pipes 34 are each provided with a plurality of supply ports 30, 30, . . . In this modified example, the blade 31, the shaft 32, and the two supply pipes 34, 34 correspond to an example of a rotating part. Note that, in this fourth modified example, the blade 31, the shaft 32, and the two supply pipes 34, 34 also rotate clockwise in FIG. 6(b). As shown in FIG. 6(a), the shaft 32 has an inner shaft flow passage 32a formed only in the upper part. In addition, the supply pipe 34 has an inner supply pipe flow passage 34a formed inside, the upper and lower ends of which are closed. A connecting portion 32b is formed at the top of the shaft 32 and the top of the supply pipe 34 to connect and fix the shaft 32 and the supply pipe 34, and a through hole is formed inside the connecting portion 32b to connect the shaft inner flow path 32a and the supply pipe inner flow path 34a. Four supply ports 30 are opened on the outside of the supply pipe 34 toward the rotation radius direction for each supply pipe 34. The number of supply ports 30 may be more than four or less than four. Each of these supply ports 30, 30... is connected to the supply pipe inner flow path 34a. The fine bubble liquid that flows into the shaft inner flow path 32a through the rotary joint 321 is discharged from each supply port 30 toward the rotation radius direction of the shaft 32. In FIG. 6(a), the discharge direction of the fine bubble liquid is indicated by a straight arrow.

[0038] In the agitator 3 of the fourth modified example, the supply port 30 faces the direction of the rotation radius of the supply pipe 34, so that as the supply pipe 34 rotates, the fine bubble liquid in the flow path 34a in the supply pipe is subjected to a centrifugal force to be discharged from the supply port 30. In addition, since there are multiple supply ports 30 for each supply pipe 34, there is little resistance when the fine bubble liquid is discharged. As a result, the fine bubble liquid can be discharged from the supply port even if the suction force of the pump 51 for the fine bubble liquid is small. Therefore, the power of the pump 51 can be reduced. In addition, since each supply port 30 is formed in the supply pipe 34 that moves by rotation, sludge in the wastewater is unlikely to enter the supply port 30 when the blade 31 is rotating. Furthermore, since the supply port 30 opens sideways, even if viscous matter such as sludge or solid matter settles from above, the viscous matter or solid matter will not enter the supply port 30. This further reduces the risk of the supply port 30 being blocked.

[0039] Next, a description will be given of a fifth modified example of the agitator 3. In the description of the fifth modified example, differences from the fourth modified example will be mainly described, and descriptions overlapping with the fourth modified example will be omitted in some cases.

[0040] Fig. 7(a) is a plan view showing a fifth modified example of the stirring device shown in Fig. 1 and Fig. 2, and Fig. 7(b) is a cross-sectional view of the stirring device shown in Fig. 7(a) taken along line CC. In Fig. 7(a) as well, the motor 33 is omitted.

[0041] As shown in Fig. 7(a), the agitator 3 of this fifth modified example differs from the agitator 3 of the fourth modified example in that only one supply pipe 34 is fixed to the shaft 32. Note that, in this fifth modified example, the blade 31, shaft 32, and supply pipe 34 also rotate clockwise in Fig. 6(b). As shown in Fig. 7(a), the fine bubble liquid that flows into the shaft inner flow path 32a through the rotary joint 321 all flows into the supply pipe inner flow path 34a in one supply pipe 34, and is discharged from the four supply ports 30, 30, ... formed in the supply pipe 34 in the direction of the rotation radius of the shaft 32. In Fig. 7(a), the discharge direction of the fine bubble liquid is indicated by a straight arrow.

[0042] The stirrer 3 of the fifth modified example has the same effect as the stirrer 3 of the fourth modified example, and since there is only one supply pipe 34, the stirrer 3 can be constructed at a low cost. However, since there is only one supply pipe 34 in the fifth modified example, the center of gravity is largely eccentric with respect to the rotation axis of the blade 31, shaft 32, and supply pipe 34, and vibration occurs when the blade 31, shaft 32, and supply pipe 34 are rotated at high speed. For this reason, when the blade 31, shaft 32, and supply pipe 34 are rotated at high speed, it is preferable to use the stirrer 3 of the fourth modified example rather than the stirrer 3 of the fifth modified example.

[0043] From the air bubble supply facility 1 of the embodiment and the modified example described above, A storage tank for storing a liquid; A stirring device that stirs the liquid stored in the storage tank; a supply port for supplying fine bubble liquid to the storage tank, This leads to the concept of a bubble supply facility characterized in that the supply port is provided in a working part that is in operation.

[0044] Here, the moving part may be a rotating part or a linear moving part. By providing the supply port in the moving part, clogging of the supply port can be prevented.

[0045] Next, a bubble supplying facility 1 according to a second embodiment will be described.

[0046] FIG. 8 is a cross-sectional view similar to FIG. 2, showing an air bubble supply facility according to the second embodiment.

[0047] As shown in Fig. 8, the air bubble supply facility 1 of the second embodiment differs from the air bubble supply facility 1 of the previous embodiment shown in Fig. 1 and Fig. 2 in that the agitator 3 does not have a rotary joint 321, a driven pulley 322, a driving pulley 332, and a V-belt 333, and that the fine bubble liquid is directly supplied from the liquid supply device 5 to the aeration tank 2. The shaft 32 of the agitator 3 is composed of a solid shaft. This shaft 32 is connected to the output shaft 331 of the motor 33 by a shaft coupling 334, and rotates in synchronization with the rotation of the motor 33. The output shaft 331 of the motor 33 may be formed long and used as the shaft 32.

[0048] Water sucked up from the liquid tank 50 by the pump 51 of the liquid delivery device 5 is mixed with fine bubbles by the bubble liquid generation device 53 to generate fine bubble liquid. The generated fine bubble liquid is then discharged from the tip of the bubble liquid delivery pipe 52 into the aeration tank 2. In this embodiment, the opening at the tip of the bubble liquid delivery pipe 52 becomes the supply port 30. The tip side portion of the bubble liquid delivery pipe 52 extends vertically below the water surface WL of the wastewater stored in the aeration tank 2. The fine bubble liquid sucked up by the pump 51 is discharged downward into the stored wastewater from the supply port 30 arranged in the aeration tank 2. In FIG. 8, the discharge direction of the fine bubble liquid is indicated by a straight arrow.

[0049] In the air bubble supply facility 1 of the second embodiment, the control device 7 controls the pump 51 to adjust the supply amount of fine bubble liquid to the aeration tank 2 according to the dissolved oxygen concentration in the wastewater stored in the aeration tank 2. This makes it possible to reduce power consumption in the pump 51. Furthermore, since the supply port 30 opens downward, the supply port 30 will not be blocked and clogged even if viscous matter such as sludge or solid matter settles from above. In addition, since the fine bubble liquid is directly supplied from the liquid delivery device 5 to the aeration tank 2, the rotary joint 321 and the like are not required, and the air bubble supply facility 1 can be constructed at low cost.

[0050] Next, a modified example of the air bubble supply facility 1 of the second embodiment will be described. In the description of this modified example, differences from the second embodiment will be mainly described, and descriptions overlapping with the second embodiment may be omitted.

[0051] FIG. 9 is a cross-sectional view similar to FIG. 8, showing an air bubble supply facility according to a modified example of the second embodiment.

[0052] As shown in Fig. 9, the air bubble supply facility 1 of this modification is different from the second embodiment shown in Fig. 8 in that the tip of the bubble liquid delivery pipe 52 faces horizontally. The tip of the bubble liquid delivery pipe 52 extends horizontally from near the side wall of the aeration tank 2 to near the blade 31. Therefore, the supply port 30 formed at the tip of the bubble liquid delivery pipe 52 opens sideways. Water sucked up by the pump 51 is generated as fine bubble liquid by adding fine bubbles by the bubble liquid generating device 53. The generated fine bubble liquid is then discharged sideways from the supply port 30 near the blade 31. In Fig. 9, the discharge direction of the fine bubble liquid is indicated by a straight arrow.

[0053] The air bubble supply facility 1 of this modified example has the same effects as the air bubble supply facility 1 of the second embodiment. Furthermore, since the supply port 30 is disposed in the vicinity of the blades 31, the stirring performance of the fine bubble liquid is improved.

[0054] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the claims. For example, in this embodiment, the bubble supply facility 1 is described as being applied to a sewage treatment plant, but it may also be applied to aquaculture farms. When used in a sewage treatment plant, the bubble supply facility of the present invention may be applied as a liquid treatment facility that switches between anaerobic biological treatment or biological treatment in an anoxic state and aerobic biological treatment. When performing anaerobic biological treatment or biological treatment in an anoxic state, the pump 51 of the liquid delivery device 5 may be stopped at all times. Furthermore, in the description of this embodiment, the concentration sensor 6 is placed in the aeration tank 2 to control the supply amount of fine bubble liquid, but the supply amount of fine bubble liquid may be controlled according to the inflow amount of sewage into the aeration tank 2 without using the concentration sensor 6. Furthermore, in this embodiment, the supply port 30 is provided below the water surface WL of the sewage stored in the aeration tank 2, but the supply port 30 may be provided above the water surface WL to discharge fine bubble water from above toward the water surface WL. In addition, a flow control valve may be provided upstream or downstream of the bubble liquid generating device in the bubble liquid delivery pipe 52, and the opening degree of the flow control valve may be controlled by the control device 7. The air bubble supply facility 1 may also be equipped with a solar power generation device to be used in the event of a power outage due to a disaster or other reason. The air bubble supply facility 1 of the present invention can be driven with little power, so the air bubble supply facility 1 can be driven even if the solar power generation device generates little power.

[0055] According to the embodiment and modified examples described above, it is possible to provide the air bubble supply facility 1 that reduces power consumption.

[0056] Note that even if a component is included only in the description of each of the embodiments and modified examples described above, that component may be applied to other embodiments or other modified examples.

[0057] The bubble supply facility described above includes a storage tank for storing a liquid containing viscous and solid matter, A stirring device that includes a rotating part that rotates in the storage tank and stirs the liquid stored in the storage tank. Placement and A supply port for supplying fine bubble liquid to the storage tank; A liquid delivery device that delivers the fine bubble liquid to the supply port; a supply amount adjusting means for adjusting the supply amount of the fine bubble liquid supplied from the supply port; Equipped with the rotating portion forms a downward circulating flow of liquid in the storage tank in the vicinity of the rotating portion, The supply port is characterized in that it supplies the fine bubble liquid downward along the circulating flow.

[0058] The rotating part has a blade and a shaft, The supply port may be provided at a lower end of the shaft.

[0059] Also, a storage tank for storing liquid; A stirring device that stirs the liquid stored in the storage tank; A supply port for supplying fine bubble liquid to the storage tank; A liquid delivery device that delivers the fine bubble liquid to the supply port; The liquid supply system may further include a supply amount adjustment means for adjusting the amount of the fine bubble liquid supplied from the supply port.

[0060] Here, the liquid delivery device may include a bubble liquid generating device that generates the fine bubble liquid. The liquid delivery device may have a pump, and the supply amount adjustment means may include a control means that controls the pump. The supply amount adjustment means may drive the pump intermittently.

[0061] According to this air bubble supply facility, the fine bubble liquid is supplied to the storage tank, so less power is consumed compared to pumping air to the bottom of the tank. Also, since many of the fine bubbles contained in the supplied fine bubble liquid are mixed with the liquid, there is no need to spray a large amount of air bubbles into the liquid. Furthermore, since the agitator is provided, there is no need to supply air bubbles for agitation, and since the fine bubble liquid is supplied, there is no need to supply air bubbles to prevent clogging of the supply port. And, since the supply amount of the fine bubble liquid is adjusted by the supply amount adjustment means, the power consumption in the liquid transfer mechanism can be reduced.

[0062] In this air bubble supply facility, a concentration sensor is provided for detecting a dissolved oxygen concentration contained in the liquid stored in the storage tank, The supply amount adjusting means may adjust the amount of the fine bubble liquid supplied from the supply port in accordance with the dissolved oxygen concentration detected by the concentration sensor.

[0063] By controlling the amount of fine bubble liquid supplied according to the dissolved oxygen concentration, it is possible to ensure the amount of oxygen required for the liquid while preventing the fine bubble liquid from being supplied in excess, thereby efficiently reducing the amount of electricity consumed in the air bubble supply facility.

[0064] Furthermore, in this air bubble supply facility, the stirring device is provided with a rotating part that rotates in the storage tank, The supply port may be formed in the rotating portion.

[0065] Since the supply port is formed in the rotating portion, the risk of sludge or the like remaining in the supply port and causing clogging can be further reduced.

[0066] In addition, in this air bubble supply facility, the supply port may be configured to eject the fine bubble liquid in a direction opposite to the rotation direction of the rotating part.

[0067] In this way, the fine bubble liquid is ejected into the liquid by the rotation of the rotating part, thereby further reducing the power consumption of the liquid transport mechanism.

[0068] In addition, in this air bubble supply facility, the supply port may be configured to eject the fine bubble liquid in the direction of the radius of rotation of the rotating part.

[0069] In this way, the fine bubble liquid is ejected into the liquid by centrifugal force generated by the rotation of the rotating part, thereby further reducing the power consumption of the liquid transport mechanism.

[0070] In this air bubble supply facility, the supply port may be open facing downward or sideways.

[0071] According to this aspect, even if viscous matter such as sludge or solid matter settles from above the supply port, the supply port is unlikely to be blocked, so clogging of the supply port can be further suppressed. The bubble supply facility described above includes a storage tank for storing a liquid containing viscous or solid matter; A stirring device that stirs the liquid stored in the storage tank; A supply port for supplying fine bubble liquid to the storage tank; a liquid delivery device that delivers the fine bubble liquid to the supply port, The agitator forms a circulating flow of liquid having a downward flow in the storage tank, The supply port is characterized in that it supplies the fine bubble liquid downward along the circulating flow. This air bubble supply facility may be provided with a supply amount adjustment means for adjusting the amount of the fine bubble liquid supplied from the supply port. [Explanation of symbols]

[0072] 1. Air bubble supply facility 2 Anaerobic tank 3 Stirring device 6 Concentration Sensor 30 Supply port 51 Pump 53 Flow control valve

Claims

1. A storage tank for storing a liquid containing viscous and solid matter; A stirring device that stirs the liquid stored in the storage tank; A supply port for supplying fine bubble liquid to the storage tank; a liquid delivery device that delivers the fine bubble liquid to the supply port, the agitator has a blade disposed in a horizontally open area and a shaft to which the blade is fixed at a lower end portion for rotating the blade, and forms a circulating flow of liquid having a downward flow in the storage tank; The supply port is formed at the lower end of the shaft and supplies the fine bubble liquid downward along the circulating flow into an area that is open in the horizontal direction.

2. A concentration sensor for detecting a dissolved oxygen concentration contained in the liquid stored in the storage tank; The air bubble supply facility according to claim 1, further comprising a supply amount adjustment means for adjusting the amount of the fine bubble liquid supplied from the supply port in accordance with the dissolved oxygen concentration detected by the concentration sensor.

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