JP2001090049A - Uniform overflow weir and uniformly overflowing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a uniform overflow weir which allows water to uniformly overflow the weir without requiring the adjustment of the height of the weir by means of an opening/closing machine in a channel in which a water head difference occurs due to a hydraulic gradient and a uniformly overflowing method. SOLUTION: A uniform overflow weir is composed of a plurality of movable weirs 7 provided at intervals in a channel along the flowing direction of water. The movable weirs 7 are provided with sheathings 8 having overflow holes 13, the same width, and the same height and the overflow holes 13 are formed in such a way that the lower end sections 14 of the holes 13 are formed at the same right-end, left-end, or central position of the base sections 15 of the sheathings 8. The base sections 15 are formed to have crossing angles θ of 0-90 deg. against the horizontal direction starting from the lower end sections 14. Between adjacent movable weirs 7, the crossing angle θ of the overflow hole 13 of the upstream-side weir 7 is made larger than that θ of the overflow hole 13 of the downstream-side weir 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a uniform overflow weir and a uniform overflow method effective in a water storage facility such as an aeration tank in a sewage treatment plant.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a sewage treatment flow by an activated sludge method. Sewage is first naturally separated into supernatant water and sludge in a sedimentation tank 81, and the supernatant water flows into an aeration tank 82 as treated water 84. . The treated water 84 is subjected to aeration and stirring (aeration) for a predetermined time in an aeration tank 82, and the treated water 85 flows into a final sedimentation basin 83, and the supernatant water is guided to the next step or discharged. You. Further, the sludge settled in the final settling basin 83 (activated sludge 86) has the ability to purify sewage (eg, activates the action of aerobic microorganisms to promote the adsorption and oxidation of organic substances), and thus is aerated. It is returned to the tank 82, and is again subjected to the aeration process together with the treated water 84 from the settling basin 81.

FIG. 7 is a structural sectional view showing an example of the aeration tank 82, and FIG. 8 is a view taken in the direction of the arrow G in FIG. 7. The aeration tank 82 has a plurality of aeration devices (not shown) inside. The storage tank has a substantially rectangular parallelepiped volume. Reference numeral 87 denotes an inflow channel for guiding the treated water 84 to the aeration tank 82, and is formed along the longitudinal direction of the aeration tank 82 (the direction orthogonal to the plane of FIG. 7). A plurality of inflow ports 88 are formed in the inflow water channel 87 at predetermined intervals along the longitudinal direction, and a movable weir 89 for adjusting the flow rate is attached to each of the inflow ports 88. The movable weir 89 has a fixed door stop 9
0, and a weir plate 91 that moves up and down by a manual switchgear 92 with a handle. The weir plate 91 is formed with an overflow hole 91a through which the treated water 84 overflows. .

The overflow from each movable weir 89 is uniform from the viewpoint of uniforming the distribution of the sludge in the treated water 84 and the distribution of the activated sludge 86 in the aeration tank 82, that is, the efficiency of the aeration treatment. It is desirable. Here, the inflow channel 87 is generally a narrow channel with a small channel width and a channel height. Therefore, as shown in FIG.
A so-called hydrodynamic gradient in which L decreases tends to occur. Therefore, conventionally, in consideration of the head difference of the water level WL due to the hydrodynamic gradient, the handle of the switch 92 is rotated so that the overflow water depth h of each overflow hole 91a becomes equal, and the height of the weir plate 91 is increased. , The overflow rate of each movable weir 89 is equalized.

[0005]

As described above, according to this method, the heights of the dams 91 are different from each other. However, due to, for example, maintenance,
When the height of the handle is changed once and all the dams 91 are returned to the original set height again, the operator has to remember the number of turns of the handle, which is troublesome. Human errors such as mistakes are also likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is not necessary to adjust the height of a movable weir by a switch in a water channel in which a head difference due to a hydraulic gradient is generated. It is an object of the present invention to provide a uniform overflow weir and a uniform overflow method capable of uniformly flowing water.

[0007]

The present invention uses the following means to achieve the above object. A uniform overflow weir composed of movable weirs that are provided at intervals along the water flow direction of the water channel and whose overflow holes are formed in a direction perpendicular to the water flow direction. Each overflow hole has a lower end portion at the same position with respect to each of the weir plates, and a right end, a left end, or a center position at the bottom side. The bottom is formed so as to have an intersection angle within a range of 0 to 90 degrees with respect to the horizontal direction from the lower end as a base point, and between adjacent movable weirs, the movable weir located on the upstream side The crossover angle at the overflow hole is a uniform overflow weir whose value is greater than the crossover angle at the overflow hole of the movable weir located downstream.

In addition, in a movable weir provided at intervals along the water flow direction of the water channel and the overflow hole is formed in a direction orthogonal to the water flow direction, a head difference due to a hydraulic gradient occurs in the water channel. A method of evenly overflowing the water from each movable weir when the overflow holes of the movable weirs have the same area below a predetermined hydraulic gradient line of the water channel. In addition, a uniform overflow method for uniformly overflowing water from each movable weir is formed by forming the bottom portion so as to have mutually different crossing angles within a range of 0 to 90 degrees with respect to the horizontal direction. did.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a case where a uniform overflow weir and a uniform inflow method according to the present invention are applied to a water storage treatment facility will be described. 1 is a schematic top view showing a water storage treatment facility equipped with a uniform overflow weir, FIG. 2 is a schematic sectional view of the same, FIG. 3 is a perspective view of a movable weir, and FIG. 4A shows a case where the lower end of the overflow hole is located at the right end, and FIG. 4B shows a case where the lower end of the overflow hole is located at the center.

In FIG. 1 and FIG. 2, reference numeral 1 denotes a water storage treatment facility, which comprises an aeration tank 2 as a water storage tank and an inflow water channel 3. The aeration tank 2 and the inflow water channel 3 are formed by a concrete wall and are juxtaposed. Aeration tank 2
Is provided with a plurality of aeration devices (not shown) therein, stores the treated water flowing in (overflow) from the inflow water channel 3 through the plurality of inflow ports 4 for a predetermined time, aerates the treated water, and then terminates the next step. This is a reaction tank that flows out to a precipitation tank. Inflow channel 3
Is a mixture of wastewater from the first settling basin and activated sludge returned from the final settling basin at a predetermined ratio (treated water)
In the present embodiment, first, the water channel is branched on the settling basin side, and each branch channel is connected to both longitudinal walls 5 of the aeration tank 2.
There is a structure along.

The inflow port 4 is formed in a rectangular shape in a wall portion 5 that partitions the aeration tank 2 and the inflow water channel 3, and is formed at a predetermined interval along the inflow water channel 3, that is, at a predetermined interval with respect to the aeration tank 2. Is formed. In this embodiment, the inlets 4 are provided at three places on both wall portions 5.

The equal overflow weir 6 according to the present invention is provided at intervals along the water flow direction of the water channel (inflow water channel 3) (provided at each of the inlets 4), and the overflow hole 13 is provided in the water flow direction. And a movable weir 7 formed in a direction orthogonal to the vertical direction. An example of the movable weir 7 will be described with reference to FIG. 3. The basic configuration of the movable weir 7 is a weir plate 8 having a rectangular shape and a U-shape with its opening side facing upward. 8 comprises a door stop 9 serving as a support for vertically ascending and descending from both sides. 9 per door
Fixed to the edge of The raising and lowering of the weir plate 8 is performed by a manually operated switch 10 positioned above, and the handle 11 is rotated to move the weir plate 8 up and down via the rod 12. Although not shown, a closing plate portion is provided below the door stop 9 to prevent overflow at the lower portion even when the weir plate 8 moves upward. In the present invention, the adjustment of the height of the weir plate 8 by the switch 10 is performed at the time of maintenance or sudden change of the overflow rate.

In the uniform overflow weir 6, the weir plates 8 of the movable weirs 7 have the same width and the same height as each other, and are formed on each weir plate 8 as shown in FIG. The overflow hole 13 is
The lower end portion 14 is located at the same position with respect to each of the weir plates 8 and at the right end, the left end, or the center position of the bottom portion 15. Is formed so as to have an intersection angle θ within a range of about 90 degrees, and between the adjacent movable weirs 7, the intersection angle θ at the overflow hole 13 of the movable weir 7 located on the upstream side
Is larger than the intersection angle θ at the overflow hole 13 of the movable weir 7 located on the downstream side.

First, in FIG. 4A, each overflow hole 13
Is formed in a rectangular shape in an upper portion, and a bottom portion 15 is formed in an inclined shape or horizontally in a lower portion. FIG. 4A shows a case where the lower end portion 14 is located at the right end of the base portion 15, and the base portion 15 is formed linearly with the lower end portion 14 as a lower end. And each intersection angle θ
The relationship of the intersection angle θ in the movable weir 7 located upstream, middle, and downstream of the inflow water channel 3 is θ1, θ
If θ2 and θ3, then “θ1>θ2> θ3”. Therefore, the overflow hole 13 at which the intersection angle θ = 0 ° is only in the case of the movable weir 7 located at the most downstream position.

The value of each intersection angle θ is determined as follows. First, in the inflow channel 3, flow rate fluctuation data and hydraulic gradient data are measured, and these are totaled to set an average hydraulic gradient line (indicated by the symbol D) of the water level WL. And
The intersection angles θ are determined such that the areas (opening areas) of the overflow holes 13 below the hydraulic gradient line D are the same. As a result, the treated water overflows from each overflow hole 13 evenly, and even if the flow rate and the hydrodynamic gradient line D fluctuate, the overflow rate is equalized in the long term. Therefore, in the aeration tank 2, the distribution of sludge and activated sludge contained in the treated water is always uniform, and a predetermined aeration efficiency is maintained. The lower end 14
At the left end to form the overflow hole 13 (that is,
In FIG. 4 (a), the bottom 15 of the movable weir 7 on the upstream side and the middle side is inclined upward to the left, while inclined downward to the right.) The same effect can be obtained. .

Also, as described above, by equalizing the overflow by the difference in the shape of each overflow hole 13, the height of the weir plate 8 becomes the same in any of the movable weirs 7, and therefore, as in the conventional case. By changing the height of each weir plate 8 (by changing the number of rotations of the handle), it is possible to eliminate troublesome work such as adjusting the overflow rate, thereby preventing the labor burden of the operator and human error. Is realized.

FIG. 4B shows a case where the lower end portion 14 is located at the center of the base portion 15. In this case, the bottom portion 15 is linearly inclined right and left around the lower end portion 14, and the intersection angle θ is formed as a pair. In the present invention, the paired intersection angle θ has the same value. And one of the intersection angles θ is referred to as an intersection angle in the present invention. Also in the case of this example, the crossing angles θ at the movable weirs 7 located upstream, middle, and downstream of the inflow water channel 3 are θ1,
Assuming θ2 and θ3, the relationship is “θ1>θ2> θ3”. Of course, θ3 in the downstream movable weir 7 may be 0 degree. Also in the case of this example, the intersection angles θ are determined so that the areas (opening areas) of the overflow holes 13 below the hydraulic gradient line D are the same.

As described above, each overflow hole 13 is connected to the lower end 1.
4 are located at the same position with respect to each weir plate 8, and the bottom 15 is 0
It is effective to form the crossing angle θ within the range of degrees to 90 degrees for the following reason. As shown in FIG. 5, all of the overflow holes 13 'are formed in a rectangular shape, and the height of the overflow holes 13' is increased toward the downstream, so that the height of the overflow holes 13 'is lower than the hydraulic gradient line D. Overflow hole 13 '
For example, when the areas of the inflow channels 3 are equalized, for example, the flow rate of the inflow water channel 3 fluctuates, the water level WL decreases, the flow velocity also decreases, and the water level WL is in a horizontal state (reference D 'shown in FIG. 5). In this case, since the heights of the bottoms of the overflow holes 13 'are different from each other, the overflow overflows only from the movable weir 7' on the downstream side, and does not overflow at all from the movable weir 7 'on the upstream and middle flows. A situation may occur.

On the other hand, if the bottom portion 15 is formed so as to have different crossing angles within the range of 0 to 90 degrees with respect to the horizontal direction as in the present invention, the lower end portions 14 are particularly the same. If the position, that is, the height of the lower end of each overflow hole 13 is the same, a difference in the magnitude of the overflow will occur, but a situation in which the overflow is not overflown from the upstream or middle movable weir 7 at all is prevented. Is what you can do. In addition,
The lower end portions 14 are located at the same position in the width direction. However, when forming the overflow hole 13 in the weir plate 8,
If the lower end 14 is positioned at the right end, left end, or center of the bottom 15, the design and processing of the overflow hole 13 are further facilitated and effective.

The preferred embodiments of the equal overflow weir and the equal overflow method according to the present invention have been described above. However, the present invention is not limited to the above-mentioned water storage equipment such as an aeration tank, and can be applied to the same. It becomes. Dam 8
As a method for forming each overflow hole 13 in the above, for example, first, a rectangular hole having the same shape is formed in all of the weir plate 8, and a block material or a plate material having a triangular shape or the like is applied to a lower portion of the rectangular hole. Thus, the common use of the weir plate 8 can be achieved, which is an effective means in processing. Further, the bottom 15 of the overflow hole 13 may be made movable so that the intersection angle θ can be set freely. Further, the shape of each overflow hole 13 may be an inverted trapezoidal shape or the like. In addition, the shape, layout, and the like of each component are not limited to those described in the drawings, and design changes can be made without departing from the spirit of the present invention.

[0021]

According to the present invention, when water is uniformly allowed to flow from each movable weir in a water channel in which a hydraulic gradient is generated, the height of each weir plate is made different from that of the prior art (rotation of the handle). By making the number different), troublesome work such as adjusting the overflow rate can be eliminated, and the burden on the operator and the prevention of human error are realized. Also, when forming the overflow hole in the weir plate, it becomes easy in terms of design and processing.

[Brief description of the drawings]

FIG. 1 is a schematic top view showing a water storage treatment facility equipped with a uniform overflow weir.

FIG. 2 is a schematic sectional view of the same.

FIG. 3 is a perspective view of a movable weir.

FIG. 4 is an operation explanatory view of the uniform overflow weir viewed from the front,
FIG. 4A shows the case where the lower end of the overflow hole is located at the right end.
FIG. 4B shows a case where the lower end of the overflow hole is located at the center.

FIG. 5 is an explanatory diagram showing the inconvenience when the height positions of the bottoms of the overflow holes are different from each other in each movable weir.

FIG. 6 is a sewage treatment flow chart by the activated sludge method.

FIG. 7 is an explanatory view showing a conventional water storage treatment facility, and is a structural sectional view showing an example of an aeration tank.

FIG. 8 is a view as viewed in the direction of arrow G in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water storage processing equipment 2 Aeration tank 3 Inflow waterway (water channel) 4 Inflow port 5 Wall part 6 Uniform overflow weir 7 Movable weir 8 Dam board 9 Per door 13 Overflow hole 14 Lower end 15 Bottom side θ Intersection angle D line

Claims (2)

[Claims] 1. A uniform overflow weir comprising a movable weir provided at intervals along a water flow direction of a water channel and having overflow holes formed in a direction perpendicular to the water flow direction, The weir is provided with a weir plate having the same width and the same height as the overflow holes formed therein, and each overflow hole has a lower end located at the same position with respect to each weir plate, and a right end or a bottom end portion. It is located at the left end or the center position, and the bottom side is formed so as to have an intersection angle within a range of 0 to 90 degrees with respect to the horizontal direction from this lower end as a base point, and between the adjacent movable weirs, on the upstream side The uniform overflow weir, wherein the crossing angle of the overflow hole of the movable weir located is larger than the intersection angle of the overflow hole of the movable weir located downstream. 2. A movable weir, which is provided at intervals along the water flow direction of the water channel and whose overflow hole is formed in a direction perpendicular to the water flow direction, causes a head difference due to a hydraulic gradient in the water channel. A method of uniformly overflowing water from each movable weir at the same time, wherein the overflow holes of each movable weir have the same area below a predetermined hydraulic gradient line of the water channel. In addition, the bottom portion is formed so as to have a crossing angle different from each other within a range of 0 to 90 degrees with respect to the horizontal direction, so that water can uniformly overflow from each movable weir. Overflow method.