JP4696390B2 - Coagulation sedimentation equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention is provided with a raw water outlet for discharging raw water (flocculating agent and sludge mixed liquid) that is hollow and supplied into the sludge blanket layer into the sludge blanket layer in the sludge blanket layer at the bottom of the settling tank (thickener). The raw water supply member (distributor) is swung horizontally in one direction, the turbidity and fine SS in the raw water discharged from the raw water outlet are filtered and separated by the sludge blanket layer, and the sludge layer containing newly generated sludge A sludge blanket type coagulating sedimentation apparatus that drains mud from the center of the bottom of the settling tank while concentrating it with a mud collecting member (rake) that swirls together with the raw water supply member, In particular, the raw water supply member is improved to smoothly discharge raw water into the sludge blanket layer and prevent the raw water outlet from being blocked by the raw water.
[0002]
[Prior art]
According to Japanese Patent Application Laid-Open No. 10-202009 proposed by the present patent applicant, the sludge blanket layer at the bottom in the settling tank is provided with a raw water outlet for discharging the raw water supplied inside into the sludge blanket layer. In addition, a sludge blanket type coagulating sedimentation apparatus in which the raw water supply member is provided so as to be horizontally rotatable is known. In this known coagulating sedimentation apparatus, a raw water outlet for discharging raw water into the sludge blanket layer is provided rearwardly upward from the lower surface with respect to the direction of rotation of the raw water supply member, and is discharged from the raw water outlet. In order to prevent the flow of the raw water from fluidizing the sludge blanket layer, the raw water supply member is also fixed with a rectifying plate that protrudes backward with respect to the swivel direction on the upper surface of the raw water supply member.
[0003]
[Problems to be solved by the invention]
The above known coagulation sedimentation apparatus achieves the desired effect as it is, but if you point out the problem,
(1) Although the raw water outlet is provided rearward and away from the lower surface of the raw water supply member, the raw water to be discharged into the sludge blanket layer is the raw water in the structure of the outlet in JP-A-10-202009. There is a possibility that the raw water outlet will be blocked due to sedimentation at the bottom of the supply member.
(2) When the raw water outlet is blocked, the raw water overflows from the center well above the center column that distributes and supplies the raw water to the raw water supply member, or the raw water supply part is pushed by the weight of the raw water deposited in the raw water supply member. If tilted, horizontal turning becomes unstable, and if it is remarkable, turning becomes impossible.
(3) If a part of the raw water outlet is blocked, uniform raw water distribution cannot be performed, turbulent flow and short-circuit flow occur, and the treated water deteriorates.
(4) The structure becomes complicated when it is attempted to take measures against clogging of the raw water supply member.
Etc.
[0004]
[Means for Solving the Problems]
The present invention has been developed for the purpose of solving the above-described problems. In the sludge blanket layer at the bottom of the settling tank, the raw water supplied inside is hollow in the sludge blanket layer. In the sludge blanket type coagulating sedimentation device provided with a raw water supply member having a raw water outlet to be discharged horizontally, the raw water outlet is obliquely behind the direction of swirling of the raw water supply member. have a flow-down means for flow down downward, to the side of the settling tank is in that a 1 or a plurality of interfaces arms positioned directly above the raw water supply member to pivot horizontally radially inwardly Features. Preferably, the flow down means is an inclined bottom plate that is inclined obliquely backward and downward with respect to the swivel traveling direction of the raw water supply member, and the raw water outlet is opened on the inclined lower end. In this case, the inclined bottom plate is in a horizontal plane. The angle formed with respect to the angle is preferably 10 to 45 °. Further, the raw water supply member is provided with a baffle plate that protrudes backward with respect to the swivel traveling direction of the raw water supply member at a position above the raw water outlet, or mud collection that swirls horizontally integrally with the raw water supply member It is preferable to provide a member .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1 (A), reference numeral 1 denotes a cylindrical sedimentation tank having a mortar-like bottom, a sludge blanket layer 2 is provided at the bottom, and a sludge discharge pipe 3 is connected to the center of the bottom. Reference numeral 4 denotes a vertical inner cylinder (center column) that is driven to rotate at a low speed by a motor, a speed reducer (not shown), etc., and is supported rotatably along the center of the settling tank by an appropriate support means. Raw water is supplied from a large-diameter feed well provided concentrically and protruding upward from the liquid level of the sedimentation tank (not shown), and the lower end reaches the sludge blanket layer. At the lower end of the inner cylinder 4, for example, four raw water supply members 5 are provided radially and horizontally at equal intervals in the circumferential direction, and the tips of the raw water supply members 5 reach near the inner wall of the settling tank 1. . Each raw water supply member 5 is provided with a raw water outlet 6 for discharging the raw water supplied to the inner cylinder into the sludge blanket layer 2. In order to discharge raw water uniformly from the entire length of the raw water outlet 6, the opening area of the raw water outlet gradually increases from the end close to the inner cylinder toward the tip of the raw water supply member. Below the raw water supply member 5, there is provided a mud collecting member 7 whose lower surface runs along the mortar-shaped bottom of the settling tank and swivels together with the raw water supply member. The mud collecting member 7 is a mortar-shaped bottom of the settling tank. The sludge deposited on the bottom is moved toward the center of the bottom, collected in the sludge pipe 3, and discharged outside the system by operating the pump P. The treated water rises from the sludge blanket layer in the settling tank, overflows from the upper end of the settling tank, and is taken out. In addition, since the mud collecting member 7 is integrally provided under the raw water supply member 5 and swiveled (Claim 5), the layer height of the sludge blanket layer 2 can be lowered, and a turnbuckle, a mud collecting member rotating shaft, etc. A member for attaching and rotating the mud collecting member becomes unnecessary, and cultivation is simple and inexpensive. Moreover, the height of the sedimentation tank 1 can be lowered by lowering the installation position of the raw water supply member 5, and the apparatus can be miniaturized. The above-described configuration is the same as the above-described known sludge blanket type coagulation sedimentation apparatus.
[0006]
According to the present invention, the raw water outlet 6 of each raw water supply member 5 has flow-down means 10 for flowing the raw water obliquely backward and downward in the direction of arrow A with respect to the direction of rotation of the raw water supply member (arrow R). Item 1).
[0007]
In the illustrated embodiment, the flow down means 10 is inclined obliquely backward and downward with respect to the turning direction of the raw water supply member 5 (arrow R), and the inclined bottom plate 11 in which the raw water outlet 6 opens on the inclined lower end. (Claim 2). The angle α formed with the horizontal plane of the inclined bottom plate 11 is 10 to 45 ° (Claim 3).
[0008]
1B is an enlarged cross-sectional view of the raw water supply member of the embodiment of FIG. 1A, taken along line BB, and FIG. 2 is a diagram of an embodiment of the raw water supply member 5 having a different cross-sectional shape from the above. It is an expanded sectional view similar to 1 (B).
[0009]
The raw water supply member in FIG. 1 (B) is a rhombus or square cylinder whose cross-sectional shape is inclined, and one side of the cylinder inclined obliquely backward and downward with respect to the turning traveling direction (arrow R) is the flow down means 10. The raw water outlet 6 is opened from the lower end 11 'to the middle 12' on the other side 12 of the cylinder connected to the inclined lower end 11 '. In this embodiment, the angle α formed with the horizontal plane of the inclined bottom plate 11 is about 30 ° (Claim 3). And the rectification | straightening plate 14 which protrudes back horizontally with respect to the turning advance direction of a raw | natural water supply member is provided in the edge of the upper end of the edge | side 12 which has the raw | natural water outlet 6 of the said cylinder (Claim 4).
[0010]
This inclined rhombus or quadrangular cross-sectional cylinder may have a convex curved surface as shown by a broken line by eliminating the corners of the two ridges facing the turning direction (arrow R) of the raw water supply member.
[0011]
The raw water supply member in FIG. 2 is formed of a cylindrical body having an isosceles triangle in cross section with the top portion directed in the swivel traveling direction (arrow R), and one side of the lower half portion forming the top portion constitutes the inclined bottom plate 11 A raw water outlet 6 is opened in the lower half of the vertical bottom 13 of the cylinder connected to the lower end 11 '. In this embodiment, the angle α formed with the horizontal plane of the inclined bottom plate 11 is about 45 ° (Claim 3). And the baffle plate 14 which protrudes back horizontally with respect to the turning advancing direction (arrow R) of a raw | natural water supply member from the position slightly above the upper end of the raw | natural water outlet 6 of the vertical base 13 of a cylinder is provided. (Claim 4).
[0012]
The triangular cross section of the cylindrical body may have a convex curved surface as indicated by a broken line at the apex of the triangle facing the turning direction (arrow R) of the raw water supply member.
[0013]
To operate, the inner cylinder 4 is rotationally driven at a low speed, and the raw water supply member 5 and the mud collecting member 7 are rotated horizontally in the direction of arrow R as a unit.
[0014]
As a result, the raw water supply member 5 and the mud collecting member 7 proceed while pushing through the sludge of the sludge blanket layer 2, and the mud collecting member 7 moves the sludge deposited on the bottom of the settling tank as described above toward the center of the bottom, On the other hand, the raw water supplied to each raw water supply member 5 through the inner cylinder 4 slides down the inclined bottom plate 11 as the flow down means 10 and enters the sludge blanket layer 2 from the lower end 11 ′ of the inclined bottom plate as the raw water outlet 6. It is discharged as a blowout flow A, and the blowout flow causes the sludge blanket layer 2 to be disturbed. If the peripheral speed of the raw water supply member 5 and the blowout speed of the raw water blown out from the raw water outlet 6 are made the same, it appears. Moreover, since the raw water blowing speed becomes zero, the disturbance of the sludge blanket layer 2 is reduced.
[0015]
For this purpose, the peripheral speed of the raw water supply member 5 is preferably 1 to 4 m / min, and on average about 2 m / min at the tip of the raw water supply member.
[0016]
Even if the rotation speed of the raw water supply member 5 and the blowing speed of the raw water from the raw water supply port 6 are operated in synchronism as described above, the raw water discharge flow A from the raw water outlet 6 remains in the sedimentation tank 1. The reversal flow B generated by colliding with the bottom of the water pushes up the sludge blanket layer 2 and disturbs it. This is prevented by the rectifying plate 14 provided rearwardly on each raw water supply member. The reverse flow B generated by the blowout flow A blown out from the raw water outlet 6 by one raw water supply member collides with the lower surface of the rectifying plate 14 of the next or further subsequent raw water supply member. This suppresses the pushing up of the sludge blanket layer. In order to enhance this suppression effect, it is preferable that the front end of the current plate 14 be provided backward near the upper edge of the raw water outlet 6, that is, as deep as possible from the interface (upper surface) of the sludge blanket layer.
[0017]
As is well known, the sludge blanket type coagulation sedimentation apparatus needs to be operated while maintaining the height of the interface (upper surface) of the sludge blanket layer 2 at a substantially constant value above the raw water supply member 5, for example, 10 to 30 cm. Therefore, the interface is always detected by an ultrasonic interface meter (not shown) installed on the water surface of the inner wall of the settling tank, and the operation of the drainage pump P connected to the drainage pipe 3 is controlled according to the change in the interface. is doing. In this case, when the sludge layer is deposited like a mountain on any one of the current plate 14 of the raw water supply member swirling horizontally, the ultrasonic interface meter detects the mountain of the sludge layer on the current plate. Then, the sludge pump P is operated to discharge more sludge from the sludge pipe 3, and there is a risk that the interface of the sludge blanket layer has a malfunction lower than a certain value.
[0018]
In order to prevent this, the inner wall of the settling tank 1 is provided with one or more interface arms 15 inward in the radial direction at a height of 1 to 5 cm above the upper surface of the raw water supply member 5 ( Claim 1 ). As a result, when a ridge of the sludge layer is deposited on any rectifying plate 14 of the raw water supply member that rotates horizontally, and the height of the ridge becomes higher than the interface arm 15, the interface arm 15 collapses the interface and Lower than the height of the arm. Therefore, if the ultrasonic interface meter is installed so as to detect the height of the sludge layer with reference to the interface arm, the above-mentioned malfunction does not occur, and the height of the interface of the sludge blanket layer 2 is determined based on the supply of raw water. The upper part of the member 5 can be kept almost constant.
[0019]
【The invention's effect】
According to the present invention, since the raw water outlet of the raw water supply member is not blocked, stable operation is possible. In addition, the structure is simple. Furthermore, since the interface of the sludge blanket layer is stable, the sludge management is easy.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view of an essential part of an embodiment of a coagulation sedimentation apparatus of the present invention, and FIG. 1B is an enlarged cross-sectional view of a raw water supply member taken along line BB of the above.
FIG. 2 is an enlarged cross-sectional view of a raw water supply member similar to FIG. 1 (B) in another embodiment of the coagulation sedimentation apparatus of the present invention.
[Explanation of symbols]
1 Sedimentation tank 2 Sludge blanket layer 3 Drainage pipe 4 Inner cylinder (center column)
5 Raw water supply parts (distributor)
6 Raw water outlet 7 Mud collection member (rake)
DESCRIPTION OF SYMBOLS 10 Flowing means 11 of raw | natural water outlet The inclined bottom plate 11 'as a flowing-down means The lower end 14 of an inclined bottom plate 14 Current plate 15 Interface arm

Claims (5)

Sludge blanket type in which a raw water supply member provided with a raw water outlet for discharging raw water supplied inside into the sludge blanket layer is horizontally swivelable in the sludge blanket layer at the bottom in the settling tank In the coagulation sedimentation apparatus of
The raw water outlet may have a flow-down means for flow down the raw water obliquely backward downward with respect to the pivot direction of travel of the raw water supply member,
The coagulation sedimentation apparatus according to claim 1, wherein one or a plurality of interface arms positioned directly above a horizontally swirling raw water supply member are provided radially inward on a side surface in the sedimentation tank .   The coagulation sedimentation apparatus according to claim 1, wherein the flow down means is an inclined bottom plate that is inclined obliquely backward and downward with respect to the swirl direction of the raw water supply member, and the raw water outlet is opened on the inclined lower end. apparatus.   The coagulation sedimentation apparatus according to claim 2, wherein the angle formed by the inclined bottom plate with respect to the horizontal plane is 10 to 45 °.   The coagulation sedimentation apparatus according to any one of claims 1 to 3, wherein the raw water supply member protrudes backward with respect to the direction of swirl of the raw water supply member at a position above the raw water outlet. A coagulation sedimentation device with a baffle plate.   The coagulation sedimentation apparatus according to any one of claims 1 to 4, further comprising a mud collection member that pivots horizontally integrally with the raw water supply member.

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