JPH0359757B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is a method for treating sewage by repeating a cycle consisting of at least an aeration process, a sludge standing separation process, and a supernatant liquid drawing process in a single treatment tank, for example. The present invention relates to a supernatant liquid extraction device that is suitable for use in a batch-type biological treatment apparatus that performs supernatant liquid extraction.

``Prior art'' Conventionally, as a method for discharging the supernatant liquid out of the tank in a batch-type biological treatment device, a method using a floatin pump or a submersible pump installed at the lower limit position for drawing the supernatant liquid in the treatment tank has been known. It is being However, this method had the problem that when the supernatant liquid was drawn out, the suction force of the pump disturbed the sludge interface, causing sludge to mix into the supernatant liquid, resulting in a decrease in the liquid quality of the supernatant liquid. . Therefore, in order to eliminate this drawback, a method was devised in which a supernatant liquid withdrawal pipe equipped with a float is installed inside the processing tank, and the supernatant liquid is allowed to flow down naturally through this withdrawal pipe and discharged to the outside of the processing tank. and is widely implemented.

``Problems to be Solved by the Invention'' By the way, when drawing out the supernatant liquid using the above-mentioned drawing pipe, in the aeration process and the static zone separation process of sludge, the drawing pipe should be moved so that its outlet exits from the liquid surface. At first, the supernatant liquid is pulled upward, and when the supernatant liquid starts to be drawn, it is lowered again and floated above the liquid surface. Conventionally, this drawing tube is operated in most cases by a motor with a speed reducer. However, when a motor is used, a device for switching between forward and reverse rotation is required, resulting in the disadvantage that the device becomes expensive and the structure becomes complicated.

The present invention was made in view of the above circumstances, and
By using a supernatant liquid drawing pipe equipped with a float, the supernatant liquid can be drawn out without disturbing the sludge interface, and the supernatant liquid drawing device has a simple structure and is easy to maintain and operate. The purpose is to provide.

"Means for Solving the Problems" In order to achieve the above object, the supernatant liquid drawing device of the present invention includes a communication device provided on the tank wall to communicate between the inside and outside of the tank, and a float at the tip. A supernatant liquid withdrawal pipe, which is provided with a supernatant liquid extraction port and whose base end is vertically rotatably connected to the open end inside the tank of the communication device and swings up and down as the liquid level rises and falls; , a cable body connected to the supernatant liquid drawing pipe is wound alternately around a movable pulley and a fixed pulley, and a movable cylinder is attached to the movable pulley to move the movable pulley away from or approach the fixed pulley. , and a lifting device for raising and lowering the supernatant liquid drawing tube centering on the base end by the operation of a moving cylinder.

"Function" In the supernatant liquid drawing device of the present invention, the moving cylinder of the lifting device is actuated to bring the movable pulley close to the fixed pulley, thereby floating the supernatant liquid drawing pipe to the liquid surface. The clear liquid is extracted. Also,
When the supernatant liquid is not to be drawn, the movable cylinder is operated to separate the movable pulley from the fixed pulley, so that the supernatant liquid drawing pipe is erected upward and stored.

``Example'' Hereinafter, an example of the present invention will be described in Figures 1 to 11.
This will be explained with reference to the figures.

1 in the figure is the treatment tank of the batch-type biological treatment equipment, and in this treatment tank 1, the cycle shown in Figure 9 consisting of receiving raw wastewater, aeration process, static separation process of sludge, and supernatant liquid withdrawal process is repeated. It has become possible to
This processing tank 1 is provided with a supernatant liquid drawing device A.

The above-mentioned supernatant liquid drawing device A includes a tank wall 1 of a processing tank 1.
A communication device 2 is provided at the top of the tank 1 to communicate the inside and outside of the processing tank 1 with each other;
The supernatant liquid drawing pipe 5 is rotatably connected to the supernatant liquid drawing pipe 5, and a lifting device 6 for raising and lowering the supernatant liquid drawing pipe 5.

The communication device 2 is connected to the tank wall 1 of the processing tank 1.
In a, a fixed pipe 7 consisting of a 90 degree bent pipe 7b connected to one end of a straight pipe 7a is penetrated through the tank wall 1a with the bent pipe 7b positioned horizontally in the processing tank 1. and fix the fixed pipe horizontally to the processing tank 1 of the fixed pipe 7.
It has a structure in which a flow rate regulating valve 8 is provided at the end projecting outward.

Further, in the supernatant liquid withdrawal pipe 5, a liquid collection pipe 5c having the above-mentioned withdrawal port 4 is connected to the tip of a straight pipe 5a of a predetermined length via a 45-degree bent pipe 5b, and the straight pipe 5a has a predetermined length. A 90 degree bent tube 5d is connected to the base end of the tube 5a, and the bent tube 5d at the base end is connected to the bent tube 7b of the fixed tube 7, and the bracket 5 is connected to the tank wall 1a.
They are vertically rotatably connected by a rotary joint 5f supported via e. A pair of left and right connecting plates 5g, 5g are fixedly attached to the liquid collecting pipe 5c, and above the liquid collecting pipe 5c,
The float 3 is formed by combining four pipes 3a, .
A pair of left and right mounting plates 3b, 3b attached across the left and right pipes 3a facing each other are connected to the connecting plates 5g, 5g by a connecting shaft 5h,
It is provided so as to be freely rotatable up and down with respect to the connecting plates 5g, 5g.

On the other hand, the lifting device 6 includes a support pedestal 9 which is formed of an angle material and is fixedly installed on the upper part of the tank wall 1a of the processing tank 1, and a rod 10a which is placed in the center of the upper part of the support pedestal 9 in a downward direction. Air cylinder (movable cylinder) 1 fixedly mounted in the direction
0, and a pair of front and rear rhombic mounting plates 12, 12 fixed to the tip of the rod 10a of this air cylinder 10 via a connecting member 11 are attached to the left and right of a pair of rhombic mounting plates 12, 12 with their axes facing front and back, and are mounted in the same vertical plane. A pair of left and right movable pulleys 13a, 13b that are rotatable;
The movable pulley 13 is attached to the support frame 9 with its axis directed forward and backward so that it is located slightly below the extended end of the rod 10a of the air cylinder 10.
a, 13b, and a fixed pulley 14 rotatable in the same vertical plane as the left movable pulley 13a, which is wound around the right movable pulley 13b via the fixed pulley 14, and one end of which is connected to the supernatant liquid. Two weights 1 are connected to the connecting shaft 5h of the drawn pipe 5 via a thimble 15, and the other ends are inserted into a guide pipe 16 provided vertically on the lower surface of the support frame 9.
7 and a wire rope (rope body) 18 connected to the wire rope 7. And the air cylinder 10
Two air pipes 20a, 20b each equipped with a speed controller 19a, 19b are connected to the cylinder body 10b, and these two air pipes 20a, 20b are connected to a compressed air source 22 by an air supply pipe 21. As shown in FIG. 1, the rod 10a is contracted by supplying compressed air to the cylinder body 10b through the lower air pipe 20b, and the movable pulleys 13a, 13b is raised and the fixed pulley 14
At the same time, as shown in FIG.
0a to the cylinder body 10b, the rod 10a is extended, and the movable pulleys 13a, 1
3b can be lowered to approach the fixed pulley 14. Further, a stopper 24 made of a pipe having a diameter smaller than that of the weight 17 or a member having a U-shaped cross section when viewed from above is provided at the joint of the guide tube 16 to the support frame 9. The stopper 24 allows the weight 17 to be It is designed to prevent it from coming out upward from the guide tube 16. Further, guide rails 25, 25 formed by arranging a pair of left and right angle members facing each other are attached to the front and rear sides of the interior of the support frame 9, and are connected to the mounting plates 12, 12. In the upper and lower parts of the member 11,
Wheels 26 are provided at both ends of the axles 26a, 26a, respectively.
Guide wheels 26, 26 comprising guide wheels 26, 26b and 26b are mounted with their axes facing forward and backward, and the guide wheels 26
6 and 26 are adapted to move up and down along the guide rails 25 and 25. Furthermore, a movable pulley 13a,
When the movable pulley 13b on the left reaches the rising end, a limit switch 27 is attached to which the left movable pulley 13a comes into contact, and a signal from this limit switch 27 causes the next process of the supernatant liquid drawing process, that is, receiving raw wastewater and aeration. The process is configured to begin.

Further, a level switch 28 is attached to the tank wall 1a of the processing tank 1 to detect when the level of the supernatant liquid reaches the lower limit level LWL for drawing out the supernatant liquid. A signal from the level switch 28 causes the electromagnetic switching valve 23 to be switched to the position shown in FIG.

In addition, 29 in the figure is a drainage ditch, B is settled sludge,
HWL is the upper limit level for supernatant liquid withdrawal, 31a and 31
b are speed controllers 19a and 19, respectively.
A check valve installed on a pipe bypassing air cylinder b prevents the compressed air supplied to the air cylinder 10 from passing through the bypass, and conversely prevents the compressed air supplied to the air cylinder 10 from passing through the bypass.
The air discharged from the is for circulation.

Next, the operation of the supernatant liquid drawing device A having the above structure will be explained.

When the supernatant liquid is not drawn out, such as in the aeration process or the static separation process of sludge, the rod 10a of the air cylinder 10 is at the contracted end and the weight 1 is
7 is locked to the stopper 24, and the wire rope 18
As a result, the supernatant liquid withdrawal pipe 5 is lowered so that its extraction port 4 is lower than the upper limit level HWL of the supernatant liquid withdrawal of the processing tank 1.
It is erected upward so that it is about 150 to 200 mm above.

When the supernatant liquid drawing process starts from this state and the supernatant liquid is extracted, the air cylinder 10
By extending the supernatant liquid drawing tube 5,
Tilt it down and let it float above the liquid surface. That is,
By switching the electromagnetic switching valve 23 from the position shown in FIG. 1 to the position shown in FIG. 10, compressed air is supplied from the upper air pipe 20a to the cylinder body 10b, and the rod 10a is extended. Then, the movable pulley 13
a and 13b descend to approach the fixed pulley 14, but at the extended end of the rod 10a, the supernatant liquid drawing pipe 5
The length of the wire rope 18 that was used to stand up is now free, and as a result, the supernatant liquid withdrawal pipe 5 rotates downward at the rotary joint 5f and floats above the supernatant liquid surface. I am made to do so. Also at this time,
Since the wire rope 18 is provided with a weight 17 at its end, it will not loosen, but when the supernatant liquid level is at the supernatant liquid withdrawal upper limit level HWL, the first
As shown in FIG. 0, the weight 17 has descended to the lower end of the guide tube 16.

When the supernatant liquid withdrawal tube 5 floats to the liquid surface, the supernatant liquid flows in from the extraction port 4 located slightly below the float 3, naturally flows down the inside of the supernatant liquid withdrawal tube 5, and then flows from the fixed tube 7 to the drainage channel. It flows out to 29. Then, at the same time as the liquid level gradually decreases, the supernatant liquid drawing pipe 5
follows this and gradually falls downward in a floating state, and the liquid level reaches the supernatant liquid withdrawal lower limit level LWL as shown in FIG. Then, level switch 2
8 detects this, and in response to the detection signal, the electromagnetic switching valve 23 is switched again to the position shown in FIG. That is, the electromagnetic switching valve 23 is
When the position is switched to the one shown in the figure, compressed air enters the cylinder body 10b from the lower air pipe 20b and enters the rod 1.
0a, thereby causing the movable pulleys 13a, 1
3b rises and moves away from the fixed pulley 14, but the wire rope 18 moves up and away from the movable pulleys 13a and 13b.
Since the wire ropes 18 are wound alternately around the fixed pulleys 14, as the movable pulleys 13a and 13b rise, the wire rope 18 is pulled up and the weight 17 first reaches the stopper 24.
When the weight 17 is stopped by the stopper 24 and cannot be raised any further, the supernatant liquid withdrawal tube 5 is rotated upward about the base end via the wire rope 18 to reach the first position. As shown in the figure, it returns to the standing state.

In this way, in the supernatant liquid drawing device A having the above structure, the supernatant liquid drawing pipe 5 is used, and the fixed pipe 7 is provided at a portion below the supernatant liquid drawing lower limit level LWL of the processing tank 1, so that the supernatant liquid drawing device A has the above structure. When the liquid level is at or near the supernatant liquid drawing upper limit level HWL, the head difference between the supernatant liquid level and the fixed tube 7 becomes large, and the drawing flow rate increases (the drawing flow rate becomes large). As the liquid level of the supernatant liquid decreases and approaches the sludge interface, the above-mentioned head difference decreases and the drawing flow rate becomes smaller (the drawing flow rate becomes smaller). Therefore, when the liquid surface approaches the sludge interface, the sludge is no longer entangled, and the quality of the discharged supernatant liquid is prevented from deteriorating, and at the same time, the time required for drawing is shortened.

Furthermore, in the supernatant liquid drawing device A,
Since the supernatant liquid drawing pipe 5 is raised and lowered by the raising and lowering device 6 consisting of an air cylinder 10, movable pulleys 13a, 13b, fixed pulley 14, wire rope 18, etc., a conventional motor with a speed reducer is used. Compared to the air cylinder 10, the structure is simpler and the manufacturing cost can be reduced.In particular, since the air cylinder 10 is combined with the movable pulleys 13a, 13b and the fixed pulley 14, the air cylinder 10
The stroke can be suppressed to less than half the water depth for drawing out the supernatant liquid, and the height of the lifting device 6 can be reduced. In addition, since the lifting device 6 is installed all together on the tank wall 1a of the processing tank 1, maintenance and inspection are easy.
This makes it possible to easily adjust the expansion and contraction speed of the air cylinder 10, so that the raising and lowering speed of the supernatant liquid drawing pipe 5 can be optimally set. Further, when the liquid level of the supernatant liquid reaches the lower limit level LWL for drawing out the supernatant liquid, the level switch 28 provided in the processing tank 1 is turned on, and the electromagnetic switching valve 23 is switched by the signal from this level switch 28 to remove the supernatant liquid. Since the liquid drawing pipe 5 is designed to be pulled up, the supernatant liquid can be drawn out reliably and accurately to the set level.Also, by adjusting the position to which the level switch 28 is attached, the supernatant liquid can be removed. The drawing water depth, that is, the pulling start position of the supernatant liquid drawing pipe 5 can be freely adjusted.

In addition, the movable pulleys 13a, 13 of the lifting device 6
When moving up and down b, the guide wheels 2 of the mounting plates 12, 12 to which the movable pulleys 13a, 13b are attached
6 and 26 are guided along the guide rails 25 and 25, the movable pulleys 13a and 13b move up and down extremely smoothly, and the supernatant liquid drawing pipe 5 can be smoothly raised and lowered. Furthermore, a limit switch 27 is provided in the upper part of the inside of the support frame 9, and this limit switch 27 is connected to the movable pulley 13a.
When this is detected, the next process of the supernatant liquid withdrawal process, that is, the raw wastewater reception and aeration process, starts, so when the supernatant liquid withdrawal pipe 5 is in the liquid, the raw wastewater reception and Once the aeration has started, there is no risk of failure, and each process proceeds accurately. Furthermore, since a flow rate adjustment valve 8 is provided at the end of the fixed pipe 7 outside the processing tank 1, the flow rate for drawing out the supernatant liquid can be adjusted in advance to optimally set the time required for drawing it out. . In addition, the float 3 of the supernatant liquid withdrawal tube 5 is formed in an annular shape, and the supernatant liquid extraction port 4 is provided below the center of the float 3, so that the scum on the surface of the supernatant liquid is removed from the float. 3 and will not flow into the outlet 4.

By the way, in the above embodiment, a hydraulic cylinder may be used instead of the air cylinder 10. Further, although a four-way valve is used as the electromagnetic switching valve 23, other switching valves may be used, such as two three-way valves, for example. Further, the weight 17 includes a movable pulley 13a,
This is provided to prevent the wire rope 18 from loosening and coming off each pulley 13a, 13b, and 14 when the wire rope 13b descends, but its weight is the weight of the wire rope 18, the wire rope 18, and each pulley 1.
3a, 13b, and 14, and is usually 1.2 to 1.2 of the weight of the wire rope 18.
One that is 1.5 times heavier will be adopted. Each pulley 13a,
If a retaining member 30 as shown in FIGS. 12a and 12b is attached to 13b and 14, for example, the weight 17 can be replaced by a member that simply contacts the stopper 24 or a member that simply fixes the wire rope 18 to the support frame 9. can be used.

Further, in the lifting device 6 of the above embodiment, two movable pulleys 13a, 13b and one fixed pulley 14 were used, but the number of these is not limited.
For example, three movable pulleys and two fixed pulleys can be used, and in that case, the stroke of the air cylinder 10 can be set to 1/4 of the water depth from which the supernatant liquid is drawn. Furthermore, FIGS. 13 to 15 show other embodiments of the above-mentioned lifting device 6, and in this embodiment, a pair of left and right fixed pulleys 14a, 14b are installed at an upper position inside the support frame 9. , a connecting member 11 is attached to the tip of the rod 10a of the air cylinder 10.
One movable pulley 13 is attached via a,
When the air cylinder 10 is extended, the movable pulley 13
falls downward, and the supernatant liquid drawing pipe 5 becomes an upright state. When the air cylinder 10 is contracted, the movable pulley 13 rises, and the supernatant liquid drawing pipe 5 becomes floating above the liquid surface. . Also, in this example,
A limit switch 27a that performs the same function as the limit switch 27 is installed below inside the support frame 9.
In addition, guide rails 25a, 25a for guiding the bearing portion 13c of the movable pulley 13 are provided inside the support frame 9.

Furthermore, in the above embodiment, a level switch 28 is provided to detect the lower limit level LWL for drawing the supernatant liquid of the processing tank 1, and the supernatant liquid drawing pipe 5 is raised by a signal from the level switch 28. In place of the supernatant liquid withdrawal lower limit level
Adjust so that the weight 17 comes into contact with the stopper 24 when the float 3 comes to LWL, and this stopper 2
4 may be provided with a limit switch, and the supernatant liquid drawing tube 5 may be pulled up in response to a contact signal from the limit switch. Further, in the above embodiment, a flow rate adjustment valve 8 is provided in the fixed pipe 7 to adjust the flow rate of the supernatant liquid drawn out, but the flow rate adjustment valve 8 is an automatic valve, and a liquid level meter is installed in the processing tank 1. A plurality of sludge interface meters arranged at predetermined intervals are installed, and when the level difference between the liquid level or the extraction port 4 and the sludge interface is large, the drawing flow rate (flow velocity) is increased, and when the level difference is small, the drawing flow rate is increased. The opening degree of the automatic valve may be controlled so as to make it smaller.

In addition, in the above, the supernatant liquid extraction device A used in a batch type biological treatment equipment where the raw wastewater receiving process is performed simultaneously with the aeration process, type biological treatment equipment, and continuous flow type batch biological treatment equipment in which the receiving process of raw wastewater is also performed during the aeration process, static separation process of sludge, and supernatant liquid withdrawal process, and the receiving process, aeration process, and sludge process. It goes without saying that the same supernatant liquid extraction apparatus A can be used in a normal batch type biological treatment apparatus in which the static separation process and the supernatant liquid extraction process are performed sequentially.

"Effects of the Invention" As explained above, since the supernatant liquid drawing device of the present invention uses a supernatant liquid drawing pipe equipped with a float, the sludge interface is not disturbed when the supernatant liquid is drawn. The liquid quality of the supernatant liquid that is discharged is maintained at a high level, and the supernatant liquid withdrawal pipe can be raised by operating the movable cylinder of the lifting device to move the movable pulley away from or approach the fixed pulley. Since the device is made to be folded down, the structure of the device is simplified and maintainability and operability are improved.

[Brief explanation of drawings]

Figures 1 to 11 show one embodiment of the present invention. Figure 1 is a schematic cross-sectional view of the entire supernatant liquid extraction device installed in the processing tank, and Figure 2 is a plan view of the supernatant liquid extraction pipe. Figure 3 is a cross-sectional side view of the same essential parts, Figure 4 is a sectional view taken in the direction of the - arrow in Figure 2, Figure 5 is an enlarged view of the lifting device, and Figure 6 is seen in the - arrow direction of Figure 5. cross section,
Figure 7 is a cross-sectional view of Figure 5 in the direction of the arrow, Figure 8 is a view of Figure 5 in the direction of the arrow, Figure 9 is an explanatory diagram of the wastewater treatment process, and Figures 10 and 11 are supernatant liquid withdrawal. A schematic cross-sectional view of the entire device to explain the operation of the device, and
Fig. 12a is a schematic diagram showing the attached state of the wire rope retaining member, and Fig. 12b is a diagram showing b of Fig. 12a.
FIG. 13 is a cross-sectional view showing another embodiment of the raising/lowering device, FIG. 14 is a cross-sectional view taken along the - arrow of FIG. 13, and FIG. 15 is a cross-sectional view taken along the same arrow. DESCRIPTION OF SYMBOLS 1... Processing tank, 1a... Tank wall, 2... Communication device, 3...
Float, 4... Outlet port, 5... Supernatant liquid withdrawal pipe,
6... Lifting device, 7... Fixed pipe, 8... Flow rate adjustment valve, 1
0...Air cylinder (moving cylinder), 13a, 1
3b, 13... Movable pulley, 18... Wire rope (rope body), 14, 14a, 14b... Fixed pulley.

Claims (1)

[Scope of Claims] 1. A communication device provided on the tank wall to communicate between the inside and outside of the tank, a float and a supernatant liquid extraction port provided at the tip, and an opening inside the tank of the communication device at the proximal end. a supernatant liquid draw-out tube that is connected to the end so as to be freely rotatable up and down and moves up and down as the liquid level rises and falls;
A cable connected to the supernatant liquid withdrawal pipe is wound alternately around a movable pulley and a fixed pulley, and the movable pulley is provided with a moving cylinder that moves the movable pulley away from or approaches the fixed pulley, A supernatant liquid drawing device comprising: a lifting device for raising and lowering the supernatant liquid drawing tube centering on the base end by the operation of a moving cylinder. 2. The communication device consists of a fixed pipe that penetrates the tank wall and is fixed to a part of the tank wall that is below the lower limit level for supernatant liquid withdrawal, and a flow rate adjustment valve that is installed at the end of this fixed pipe outside the tank. A supernatant liquid drawing device according to claim 1, characterized in that: