JP2018134620A - Coagulation sedimentation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain clear treated water while achieving high-speed treatment without an increase in cost.SOLUTION: Coagulation sedimentation equipment 1 is provided with: a distributor 20 which is rotatably arranged in a sedimentation tank 10 and supplies treated water with a flocculant added to an inside of the sedimentation tank 10; and a stirring blade 30 which is mounted on the distributor 20, stirs the treated water by rotating together with the distributor 20, and granulates flocks in the treated water.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a granulation type coagulation sedimentation apparatus.

  As one of the water treatment devices, a coagulation sedimentation device is widely used for water treatment, wastewater treatment, and the like. The coagulation sedimentation apparatus aggregates suspended substances contained in raw water in a sedimentation tank to cause precipitation, and separates the raw water into sludge and treated water. That is, when the raw water supplied to the sedimentation tank passes through a fluidized bed (sludge blanket) of sludge, suspended substances and flocs in the raw water are captured by the sludge blanket, and the filtered supernatant is obtained as treated water. Will be.

  Among such agglomeration and precipitation devices, raw water to which a flocculant is added is stirred in a precipitation tank, and by repeating collision and rolling motion, the particle size of floc in the raw water is gradually increased to form spherical pellets. A granulation type coagulation sedimentation apparatus is known. In the granulation-type coagulation sedimentation device, pellets with high density and high sedimentation speed form a fluidized bed (pellet blanket), so that processing at a higher speed becomes possible and the flow rate in the sedimentation tank ( The size of the precipitation tank can also be reduced by increasing the LV).

  On the other hand, when the water flow LV in the sedimentation tank is increased, the water to be treated does not flow evenly and causes a drift, so that the sludge blanket is disturbed, and the ability to capture fine flocs by the sludge blanket decreases. . On the other hand, as a method for obtaining clear treated water even when the water flow LV is increased, a method has been proposed in which raw water is uniformly dispersed and supplied into a settling tank using a rotary distributor. (For example, refer to Patent Document 1).

Japanese Patent No. 5143762

  If it is going to adopt a rotary distributor in a granulation type coagulation sedimentation device, a driving means of a stirring blade for stirring and agglomerating the floc floc and a driving means of the distributor are required, which increases costs. .

  Then, the objective of this invention is providing the coagulation sedimentation apparatus which can obtain a clear treated water, implement | achieving a high-speed process, without increasing cost.

  In order to achieve the above-described object, the coagulation / sedimentation apparatus of the present invention coagulates the suspended matter contained in the water to be treated in a sedimentation tank and precipitates it, and separates the water to be treated into sludge and treated water. A settling device, which is rotatably installed in the settling tank, and supplies the treated water with flocculant added to the settling tank, and is attached to the distributor and rotates with the distributor to agitate the treated water. And a stirring blade for granulating floc in the water to be treated.

  In such a coagulating sedimentation apparatus, the driving means for the stirring blade is not required, and it is possible to achieve uniform distribution of water to be treated by the distributor and granulation of flocs by the stirring blade only by rotating the distributor. it can.

  As described above, according to the present invention, clear treated water can be obtained while realizing high-speed treatment without increasing the cost.

It is a schematic sectional drawing of the coagulation sedimentation apparatus which concerns on the 1st Embodiment of this invention. It is the schematic which shows the example of attachment of the stirring blade which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing of the coagulation sedimentation apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the example of arrangement | positioning of the stirring blade which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a coagulation sedimentation apparatus according to a first embodiment of the present invention.

  The coagulation sedimentation apparatus 1 is a granulation type coagulation sedimentation apparatus that separates raw water (treated water) into sludge and supernatant liquid (treated water) by coagulating and precipitating the suspended substances contained therein. 10, a distributor 20, and a plurality of stirring blades 30.

  The sedimentation tank 10 has a cylindrical shape for receiving raw water. As will be described later, a fluidized bed (pellet blanket) A composed of granulated flocs (pellets) and a clear supernatant liquid (treated water) B from which suspended substances and flocs are removed are formed in the sedimentation tank 10. Is done. At the upper end of the sedimentation tank 10, a water collection tank 11 is provided for collecting the supernatant B that has overflowed the precipitation tank 10, and the water collection tank 11 is connected to an outflow pipe 12 for taking out the supernatant B. ing. A lower end of the sedimentation tank 10 is connected to a withdrawal pipe 13 for extracting the concentrated sludge (pellet concentrated to a high concentration) accumulated at the bottom of the precipitation tank 10. In addition, a raw water introduction line 14 for introducing raw water into the precipitation tank 10 is provided at the upper part of the precipitation tank 10. Furthermore, the sedimentation tank 10 may be provided with a concentrating part for storing the above-described concentrated sludge on the lower part or the side surface. In addition, the shape of the sedimentation tank 10 is not limited to a cylindrical shape, For example, a polygonal cylinder shape may be sufficient.

  The distributor 20 is rotatably provided in the sedimentation tank 10 around a rotation axis L extending in the vertical direction, and supplies the raw water introduced from the raw water introduction line 14 while being uniformly dispersed in the precipitation tank 10. . The distributor 20 has a cylindrical raw water inflow pipe 21 extending vertically from the upper part to the lower part of the sedimentation tank 10 and a plurality of raw water supply ports 22 provided at the lower end of the raw water inflow pipe 21.

  The raw water inflow pipe 21 is connected to the motor 24 through a shaft 23 fixed to the inside of the raw water inflow pipe 21. Therefore, the raw water inflow pipe 21 can be rotated about the rotation axis L by driving the motor 24. The motor 24 is controlled by an inverter, and changes the rotational speed of the distributor 20 in accordance with the flow rate (LV) of the raw water in the settling tank 10. The plurality of raw water supply ports 22 are provided so as to open outward in the radial direction of the raw water inflow pipe 21, whereby raw water can be blown out radially outward. In addition, the number of the raw | natural water supply ports 22 is not limited to a specific number, The optimal number can be selected according to various conditions, such as a process flow rate. Further, instead of the plurality of raw water supply ports 22, one raw water supply port that opens in an annular shape may be provided on the outer peripheral surface of the raw water inflow pipe 21. In addition, the shape of the raw | natural water inflow tube 21 is not limited to a cylindrical shape, For example, a polygonal cylinder shape may be sufficient.

  The plurality of stirring blades 30 are each composed of an elongated flat plate-like member, and are provided so as to extend radially from the outer peripheral surface of the raw water inflow pipe 21 of the distributor 20. Thereby, the some stirring blade 30 rotates with the distributor 20, can stir the pellet blanket A in the sedimentation tank 10, can increase the particle size of a fine floc, and can be granulated to a spherical pellet.

  Here, operation | movement of the coagulation sedimentation apparatus 1 of this embodiment is demonstrated.

  First, a flocculant is added to raw water at the front stage of the coagulation sedimentation apparatus 1, and aggregation of suspended substances contained in the raw water is started. Then, the raw water including the flocs in the aggregation process is introduced from the raw water introduction line 14 into the sedimentation tank 10 through the raw water inflow pipe 21. Alternatively, the raw water is introduced into the settling tank 10 after adding the flocculant in the raw water inflow pipe 21 instead of adding the flocculant at the front stage of the coagulation sedimentation apparatus 1. The raw water flowing into the raw water inflow pipe 21 is discharged almost uniformly in the circumferential direction from the raw water supply port 22 provided at the lower end of the raw water inflow pipe 21 as the distributor 20 rotates. At this time, flocs in the flocculation process in the raw water are stirred by a plurality of stirring blades 30 that rotate together with the distributor 20, and are repeatedly granulated into spherical pellets by repeating collisions and rolling motions. Thus, a pellet blanket A, which is a fluidized bed of pellets, is formed in the lower part of the settling tank 10. Thereafter, the raw water supplied from near the bottom of the sedimentation tank 10 is trapped in the pellet blanket A while passing through the pellet blanket A, and settled as a filtered supernatant liquid (treated water) B. Ascend to the top of the tank 10. Then, when the supernatant B overflows the settling tank 10, it is taken out from the water collection tank 11 through the outflow pipe 12.

  Thus, in this embodiment, since the stirring blade 30 is attached to the rotary distributor 20, the stirring blade 30 can be rotated only by rotating the distributor 20. Therefore, the driving means for rotating the stirring blade 30 is not necessary, and the advantages of both the distributor 20 and the stirring blade 30 can be enjoyed without increasing the cost. That is, the processing efficiency can be improved by uniform distribution of the raw water by the distributor 20, and a clearer treated water can be obtained. At the same time, the formation of pellets by the stirring blade 30 enables a higher speed treatment.

  Moreover, in this embodiment, since the fluidized bed (pellet blanket A) is formed with pellets having a high density and a high sedimentation speed, the flow rate LV of the raw water in the sedimentation tank 10 can be increased. Can also be realized. In addition, if water flow LV is enlarged, the frequency | count of contact with the floc in raw | natural water and the stirring blade 30 will decrease, mechanical dehydration processing will not fully be performed, and it will become impossible to granulate a floc enough as a result. there is a possibility. However, in the present embodiment, the inverter 24 of the motor 24 is configured to change the rotational speed of the distributor 20, that is, the stirring speed of the stirring blade 30 according to the water LV. Therefore, even if the flow rate LV of the raw water is increased, the stirring speed can be increased accordingly, and pellets having a high density and a high sedimentation speed can be sufficiently formed. Furthermore, since the rotational speed of the distributor 20 also increases, it is possible to suppress a decrease in the dispersion efficiency of the raw water that may occur with the increase in the water flow LV.

  The number and positions of the stirring blades 30 attached to the raw water inflow pipe 21 are not limited to specific ones. As the number of the stirring blades 30, an optimal number can be selected according to various conditions such as a processing flow rate. The arrangement of the stirring blades 30 may be symmetric or asymmetric with respect to the rotation axis L of the distributor 20 (raw water inflow pipe 21). Alternatively, the stirring blades 30 may be arranged in a spiral shape or a zigzag shape along the axial direction of the raw water inflow pipe 21.

  In this embodiment, each stirring blade 30 is provided along the direction in which the longitudinal direction is normal to the outer peripheral surface of the raw water inflow pipe 21, that is, the direction orthogonal to the rotation direction (the moving direction of the stirring blade 30). Is provided along the vertical direction, but the mounting angle of the stirring blade 30 is not limited to this. FIG. 2 is a view showing another example of attachment of the stirring blade 30, and FIG. 2 (a) shows a cross section perpendicular to the axial direction of the raw water inflow pipe 21, FIG. 2 (b) and FIG. 2 (c). Indicates a plane perpendicular to the longitudinal direction of the stirring blade 30. For example, as shown in FIG. 2A, the agitating blade 30 is rotated in the direction in which the longitudinal direction is orthogonal to the rotating direction of the raw water inflow pipe 21 (the moving direction of the agitating blade 30) (see the broken line in the figure). It may be inclined and provided on the upstream side. Thereby, the rolling motion of the pellet on the stirring blade 30 can be promoted. Further, as shown in FIGS. 2B and 2C, the stirring blade 30 may be provided such that the short side direction is inclined with respect to the vertical direction. As a result, when the raw water inflow pipe 21 rotates, an upward flow (see FIG. 2 (b)) and a downward flow (see FIG. 2 (c)) are generated in the floc within the sedimentation tank 10, and Pellets can be efficiently formed by increasing the number of collisions.

(Second Embodiment)
FIG. 3 is a schematic cross-sectional view of a coagulation sedimentation apparatus according to the second embodiment of the present invention. Hereinafter, the same reference numerals are given to the same components as those in the first embodiment, the description thereof is omitted, and only the components different from those in the first embodiment will be described.

  This embodiment is different from the first embodiment in that the configuration of the distributor 20 is changed and the installation position of the stirring blade 30 is changed accordingly. Specifically, unlike the first embodiment, the raw water inflow pipe 21a of the distributor 20 is provided only at the upper part of the settling tank 10, and the lower end thereof is branched radially from the raw water inflow pipe 21a to the settling tank 10. A plurality of distribution pipes 21b extending toward the lower part of are connected. The raw water supply port 22 is provided at the lower end of each of the plurality of distribution pipes 21b so as to open downward in the axial direction. As a result, the raw water is discharged toward the bottom surface of the settling tank 10 to generate an upward flow. Can be made. Further, the plurality of stirring blades 30 are attached to the outer peripheral surfaces of the plurality of distribution pipes 21b. With such a configuration, as in the first embodiment, uniform distribution of raw water by the distributor 20 and floc granulation by the stirring blade 30 can be realized.

  The number of distribution pipes 21b may be at least two, and an optimum number can be selected according to various conditions such as a processing flow rate. Moreover, although the arrangement is not particularly limited, in order to rotate the distributor 20 in a well-balanced manner, it is preferable that the arrangement be symmetrical with respect to the rotation axis L of the distributor 20 (raw water inflow pipe 21a).

  The arrangement of the stirring blades 30 is not limited to a specific arrangement as long as the pellet blanket A is uniformly stirred. FIG. 4 is a view showing an arrangement example of such a stirring blade 30, and shows a cross section perpendicular to the axial direction of the distribution pipe 21b. For example, as shown in FIG. 4A, the stirring blade 30 is provided along the direction on both sides of the direction perpendicular to the moving direction of the distribution pipe 21 b (stirring blade 30) (see the arrow in the drawing). Also good. Alternatively, as described above, in order to promote the rolling motion of the pellets on the blade, the stirring blade 30 is inclined backward (moving direction) with respect to the moving direction of the distribution pipe 21b as shown in FIG. It may be provided so as to incline to the upstream side in the movement direction with respect to the direction orthogonal to the direction of movement. Furthermore, each stirring blade 30 may be attached to the distribution pipe 21b at an attachment angle as shown in FIG. 2 (b) and FIG. 2 (c).

  Further, in the arrangement example shown in FIG. 4, the stirring blades 30 having the same length are provided on both sides in the direction orthogonal to the moving direction of the distribution pipe 21 b, but the arrangement of the distribution pipe 21 b (for example, from the rotation axis L). Depending on the distance, ones with different lengths may be provided, or they may be provided only on one side. For example, when providing the concentration part mentioned above in this embodiment, as an installation position, not only the lower part and side surface of the sedimentation tank 10, but the center vicinity (below the raw | natural water inflow pipe 21a, it was surrounded by several distribution pipes 21b. Space) is also possible. In this case, the stirring blade 30 may not be provided on the surface of the distribution pipe 21b on the side facing the concentration portion.

DESCRIPTION OF SYMBOLS 1 Coagulation sedimentation apparatus 10 Precipitation tank 11 Catchment tank 12 Outflow pipe 13 Pull-out pipe 14 Raw water introduction line 20 Distributor 21, 21a Raw water inflow pipe 21b Distribution pipe 22 Raw water supply port 23 Shaft 24 Motor 30 Stirring blade

Claims (10)

A coagulating sedimentation apparatus for aggregating and suspending suspended matter contained in water to be treated in a sedimentation tank, and separating the water to be treated into sludge and treated water,
A distributor that is rotatably provided in the settling tank and that supplies the treated water to which a flocculant has been added, to the settling tank;
Agitating blades attached to the distributor, rotating together with the distributor to agitate the treated water, and granulating flocs in the treated water;
A coagulating sedimentation device.   The coagulation sedimentation apparatus according to claim 1, wherein the distributor is configured so that a rotation speed thereof changes according to a flow line speed of the treated water in the sedimentation tank.   The distributor has a cylindrical inflow pipe that extends in a vertical direction from the upper part to the lower part of the settling tank, is rotatably provided, and has a supply port for supplying the treated water into the settling tank at the lower end. The coagulation sedimentation apparatus according to claim 1, wherein the stirring blade is attached to an outer peripheral surface of the inflow pipe.   The coagulation sedimentation apparatus of Claim 3 with which the said supply port is provided so that it may open to the radial direction outer side of the said inflow tube.   The distributor extends vertically in the upper part of the settling tank, and is provided with a cylindrical inflow pipe that is rotatably provided, and radially extends from the lower end of the inflow pipe and extends toward the lower part of the settling tank, A plurality of distribution pipes each having a supply port for supplying water to be treated into the settling tank at each lower end, and the stirring blades are attached to the outer peripheral surfaces of the plurality of distribution pipes, The coagulation sedimentation apparatus according to claim 1 or 2.   The coagulation sedimentation apparatus according to claim 5, wherein the supply port is provided so as to open to an axially lower side of the distribution pipe.   The coagulation sedimentation apparatus of any one of Claim 3 to 6 with which the said stirring blade is provided along the direction orthogonal to the moving direction of this stirring blade.   The coagulation sedimentation apparatus according to any one of claims 3 to 6, wherein the stirring blade is provided to be inclined upstream of the moving direction with respect to a direction orthogonal to the moving direction of the stirring blade.   The coagulation sedimentation apparatus according to any one of claims 1 to 8, wherein the stirring blade is provided along a vertical direction.   The coagulation sedimentation apparatus according to any one of claims 1 to 8, wherein the stirring blade is provided to be inclined with respect to a vertical direction.

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