JP2001353408A - Flocculating and settling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flocculating and settling device in which the quality of the treated water is not deteriorated when sludge is discharged, when inflow or raw water is coming in. SOLUTION: This flocculating and settling device has the same constitution as that of the usual one except that a water level keeping/sludge discharge mechanism 68 is provided for keeping the water level in a flocculating/settling tank 70 when sludge is removed. The mechanism 68 is provided with an introduction pipe 72 on which the first automatic stop valve 74 is installed, a pump 76 for supplying the treated water to the tank 70 through the pipe 72, an interfacial level meter 78, the second automatic stop valve 80 installed on a sludge removing pipe 60 and a controller 82 for controlling the opening/closing operation of the valves 74, 80 and the start/stop of the pump 76. When the meter 78 detects that the interface between the suspended material layer and the raw water reaches the upper limit position HL, the controller 82 starts the pump 76 and opens the valves 74, 80 to discharge sludge through the pipe 60. When the meter 78 detects that the interface reaches the lower limit position LL, the controller 82 closes the valves 74, 80 and stops the pump 76.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coagulating sedimentation apparatus, and more particularly, to a coagulating sedimentation apparatus in which a cleaning interval of a contact material accumulation layer is lengthened and a water quality of a treatment liquid is not reduced during drainage. It is.

[0002]

2. Description of the Related Art Drainage of public sewage and factory wastewater is conducted by rivers,
When draining to the sea or the like, it is necessary to treat the wastewater to the standard water quality level and drain it. As a water treatment device for wastewater such as public sewage and industrial wastewater, a large number of so-called upward flow coagulation sedimentation devices are employed because of high coagulation sedimentation performance and high filtration performance and easy operation. ing. The upflow coagulating sedimentation apparatus is provided with an adding means for adding a coagulant to raw water (water to be treated including wastewater is referred to as raw water), and a small piece contact material provided with a large porosity downstream of the adding means. It has a contact material accumulation layer that is deposited, and is constituted by coagulation and sedimentation means for causing raw water to flow in the contact material accumulation layer in an upward flow to coagulate and precipitate a suspension in the raw water.

[0003] By the way, wastewater from power plants or various industrial plants has poor cohesiveness of suspended matter contained in wastewater. In order to facilitate the treatment, an organic polymer coagulant is used in addition to the inorganic coagulant as the coagulant and added to the raw water. Here, with reference to FIG. 3 to FIG. 5, a description will be given of a configuration and an operation method of a conventional upward flow type coagulation-sedimentation apparatus using an inorganic coagulant and an organic polymer coagulant in combination. FIG. 3 is a flow sheet showing the configuration of a conventional upflow coagulation sedimentation apparatus,
FIG. 4 is a schematic diagram showing the configuration of the coagulation sedimentation tank, and FIG. 5 is a perspective view showing the configuration of the contact material. As shown in FIG. 3, the conventional upflow coagulating sedimentation apparatus 10 includes a raw water tank 12, a raw water pump 14 that pumps raw water from the raw water tank 12, and feeds the raw water.
The system includes two sets of coagulant addition devices 16A and 16B, two chemical mixing tanks 18A and 18B connected in series, and a coagulation sedimentation tank 20.

A raw water supply pipe 22 connected to the discharge side of the raw water pump 14 is provided with a turbidity meter 24 for measuring the turbidity of the raw water. The coagulant adding device 16A is configured to store the inorganic coagulant from the inorganic coagulant tank 26A into the raw water supply pipe 22 downstream of the turbidimeter 24 and the inorganic coagulant tank 26A containing an inorganic coagulant such as polyaluminum chloride (PAC). Coagulant pump 2 to inject
8A, and the inorganic coagulant is injected into the raw water. The coagulant mixing tank 18A is a container provided with a stirrer 29A,
The raw water into which the inorganic coagulant has been injected is temporarily retained, and the raw water is stirred by the stirrer 29A to rapidly mix the raw water and the inorganic coagulant.

[0005] The coagulant adding device 16B includes an organic coagulant tank 26B containing an organic polymer coagulant such as polyacrylate.
And a coagulant pump 28B for pumping the organic coagulant from the organic coagulant tank 26B and injecting it into the coagulant mixing tank 18B, and injects a predetermined amount of the organic coagulant into the raw water. The coagulant mixing tank 18B includes a stirrer 29B, and is provided with a coagulant mixing tank 18A.
After the raw water mixed with the inorganic coagulant and the organic polymer coagulant are mixed slowly, the raw water is caused to flow into the coagulation sedimentation tank 20 through the inflow pipe 30.

[0006] The coagulation sedimentation tank 20 coagulates and filters coagulated flocs formed by flocculating a suspension in raw water with a coagulant.
It is a tank for separating, as shown in FIG.
A raw water inflow zone 32, a contact material accumulation zone 34, and a water collection zone 36 are sequentially formed.

[0007] The contact material accumulation zone 34 is defined by outflow prevention plates 38 and 40 which are porous separators such as mesh-like or mesh-like plates provided at the upper and lower portions of the zone.
A large number of small-piece contact materials having a high porosity, for example, a small-tube-shaped small-piece contact material 42 having a relatively small specific gravity as shown in FIG. When the raw water flows, the contact material 42 floats by the upward flow of the raw water and is deposited under the upper outflow prevention plate 38 to form the contact material accumulation layer 44, while the contact material accumulation layer 44 and the outflow prevention plate 40 A flowing water region 45 in which the contact material 42 does not exist is formed between the water flowing region 45 and the water flowing region 45.

The water collecting zone 36 includes a contact material collecting zone 34.
Is an area for collecting treated water treated by flowing
A water collecting portion 46 provided immediately above the outflow prevention plate 38 of the contact material accumulation zone 34, a water collecting trough 48 for collecting treated water overflowing from the upper end of the water collecting portion 46, and a water collecting trough 48 connected to the water collecting trough 48. And an outflow pipe 50 through which the treated water flows out, and sends the treated water to a treated water tank 52 (see FIG. 3).

The raw water from the chemical mixing tank 18 B flows into the inflow zone 32 through the inflow pipe 30. Inflow pipe 30
Has a downward opening at the tip which penetrates the center of the inflow zone 32. Below the opening of the inflow pipe 30, a current changing plate 54 having an inverted umbrella is provided in order to change the direction of raw water flowing downward into an upward direction. In addition, the inflow pipe 30
Is connected to an alkaline agent injection pipe 56, and an alkaline solution is injected as needed to adjust the pH of the raw water.

The bottom of the inflow zone 32, that is, below the current transformer plate 54, is an inverted conical sludge storage zone 58 for accumulating sludge. A sludge discharge pipe 60 for discharging sludge is provided at the lowest part thereof. It is connected. Further, an air supply pipe 62 provided with a large number of air nozzles for injecting air upward is provided above the inflow zone 32, and the air supplied by the air blower 64 is ejected to form a contact material accumulation zone 34. Contact material 4
2 is washed by stirring.

In the coagulation sedimentation tank 20, the raw water to which the coagulant has been added first flows into the inflow zone 32. In the inflow zone 32, relatively large flocs of flocs formed by agglomeration of the suspension in the raw water first settle and separate. Next, the raw water flows into the contact material accumulation zone 34.
There, the remaining minute flocs in the raw water adhere to the outer surface of the contact material and the inner surface of the contact material, or
They are separated by being caught in gaps between them. On the other hand, the raw water is a gap in the contact material 42 or the contact material 42 and the contact material 4.
2 and is filtered by the floc layer formed in the gap or between the contact materials, and the fine flocs in the raw water are captured by the floc layer.

The contact material 42 or the contact material 4
The floc captured between the two grows gradually due to contact with the subsequent minute floc and the like, and the floc diameter increases. Then, as a floc whose sedimentation velocity is larger than the rising velocity of the raw water is formed, the floc is separated from the contact material 42 by the flow of the raw water, and further sediments against the flow of the raw water, and is formed in the sludge storage zone 58. accumulate. As described above, the suspension in the raw water is separated from the raw water by the flocculation action of the suspension flocs, the filtering action on the raw water, the separation and sedimentation action of the flocs, and the like, and settles in the sludge storage zone 58. On the other hand, the raw water flows out from the upper water collecting zone 36 to the treated water tank 52 as treated water.

The upflow coagulation and sedimentation apparatus has a high density of coarse flocculated floc and a high sedimentation velocity, so that high-speed treatment of raw water is possible. Therefore, the equipment is compact and the equipment area is small. It has been evaluated that it is small, and the amount of chemicals used is small, and the sludge generated is easy to treat and dispose.

[0014]

In a coagulating sedimentation apparatus for coagulating and sedimenting waste water using an inorganic coagulant and an organic polymer coagulant in combination as a coagulant, sludge is stored by coagulation and sedimentation of a suspension. The amount of sludge deposited in the zone 58 is remarkably large as compared with the coagulation and sedimentation treatment of the tap water, and therefore, the growth of the suspended solid deposited layer or the sludge layer formed by the deposition of the suspended material is fast. Suspension continues to accumulate in the sludge storage zone 58, and the suspended sediment layer passes over the outflow prevention plate 40 and the contact material accumulation layer 44
Is reached, a large amount of flocs detached from the suspended matter accumulation layer enter the contact material accumulation layer 44.
As a result, the coagulation sedimentation filtration action of the contact material accumulation layer 44 is significantly reduced.

In other words, when the deposited suspended solids layer is left, the function of the contact material accumulation layer is reduced by the contact between the deposited suspended solids and the contact material. Therefore, in order to restore the function of the contact material accumulation layer, a cleaning operation of the contact material accumulation layer is frequently required, and a cleaning interval between the cleaning operation and the cleaning operation is shortened. As a result, a water flow operation time is shortened. That is, the time required for the contact material accumulation layer to reach the turbidity capture limit capacity is significantly shortened. Therefore, in order to lengthen the washing interval of the contact material accumulation layer of the coagulation sedimentation tank, that is, to lengthen the water flow operation time, before the suspension accumulation layer reaches the contact material accumulation layer, That is, it is necessary to discharge sludge. For this reason, it is necessary to frequently discharge the sludge accumulated in the sludge storage zone from the sludge pipe. Moreover,
In order to maintain the treatment efficiency of the coagulation and sedimentation apparatus, it is necessary to discharge sludge into the raw water. However, the conventional coagulating sedimentation apparatus has a problem in that when the sediment suspension is drained into the flowing water of the raw water, the quality of the treated water is temporarily remarkably reduced when the suspension is completely drained. Was.

Accordingly, an object of the present invention is to provide a coagulation sedimentation apparatus having a configuration in which the quality of treated water does not decrease when discharging mud while passing raw water.

[0017]

The inventor of the present invention disposes of the deposited suspended matter into the flowing water of raw water, and when the suspended matter is completely discharged, the quality of the treated water is temporarily reduced. After studying the reasons, the following was found. Depending on the size of the coagulation sedimentation tank, the flow rate of raw water, the diameter of the sludge pipe, etc.
If the flow rate of the sludge or the flow rate of the sludge is small, the sludge pipe may be blocked, so it is necessary to discharge the sludge at a high flow rate or a large flow rate. Therefore, the flow rate of sludge is usually larger than the flow rate of raw water. Therefore, when the sludge is drained during the passage of the raw water, the flow rate corresponding to the difference between the flow rate of the raw water and the flow rate of the sludge is insufficient, and the water level in the coagulation sedimentation tank 20 decreases. As a result, drainage occurs at the upper part of the contact material accumulation layer 44, and the contact material accumulation layer 44 pressed against the outflow prevention plate 38 by the buoyancy of the water itself starts to descend in the tank as the water level decreases. .

Once such a descending phenomenon of the contact material accumulation layer 44 occurs, the coagulation settling tank 2
Even if the water level inside the water rises again and the treated water overflows from the water collecting part 46, the contact material accumulation layer 4
4 does not completely function, and the quality of treated water often deteriorates temporarily. That is, the flocculated flocs trapped inside the filler deposit layer 44 are broken down as the contact material deposit layer 44 descends due to drainage,
When the water level rises again after the end of the sludge and comes into contact with the water, the fine floc passes through the contact material accumulation layer 44 with the treated water,
This is because it leaks to the water collecting part 46.

Therefore, the inventor of the present invention has proposed that even during the passage of raw water,
We believe that it is necessary to prevent the water level in the coagulation sedimentation tank 20 from lowering in order to allow sludge to be discharged without lowering the water quality of the treated water. Invented.

In order to achieve the above object, based on the above-mentioned findings, the coagulation-sedimentation apparatus according to the present invention (hereinafter referred to as the first invention) comprises: an adding means for adding a coagulant to a liquid to be treated; A coagulating sedimentation tank provided downstream of the means, for coagulating and precipitating a suspension in the liquid to be treated, wherein the treatment liquid having a lower turbidity than the liquid to be treated is flowed out. In the upper part of the tank above the porous partition which divided the inside up and down,
It has a contact material accumulation layer formed by depositing a small piece contact material with a large porosity, and flows the liquid to be treated in the contact material accumulation layer in an upward flow to aggregate and precipitate the suspension in the liquid to be treated. A coagulating sedimentation device provided with a sludge storage zone for depositing suspended solids and a sludge discharge pipe for discharging the suspended solids from the sludge storage zone as sludge at a lower part of the tank below the partition plate. In the area under the contact material accumulation layer and above the sludge storage zone, an introduction pipe for introducing the processing liquid or the liquid to be treated from outside the tank at a flow rate equal to or higher than the flow rate of the sludge is provided. The method is characterized in that sludge is discharged from a drainage pipe while introducing water into a settling tank and introducing a treatment liquid or a liquid to be treated from an introduction pipe.

In the first invention, the introduction position of the treatment liquid or the liquid to be treated is preferably at the upper part of the tank on the partition plate below the contact material accumulation layer. The configuration of the introduction pipe is not limited as long as the liquid to be processed or the processing liquid can be supplied at a predetermined flow rate. For example,
As an introduction pipe, an opening that penetrates the tank wall of the coagulation sedimentation tank and faces the porous partition plate is provided at one end, and the other end is connected to the discharge side of the processing liquid pump that pumps processing liquid from the processing liquid tank outside the tank. Provided tube. Instead of the treatment liquid pump, a gravity type utilizing a head difference may be used, but it is necessary to increase the cross-sectional area of the introduction pipe in order to reduce the pressure loss. The flow rate of the processing liquid or the liquid to be processed is set to be larger than the flow rate of the sludge. The amount of sludge is an amount defined by the distance of a sludge pipe, a pipe shape, a pipe friction coefficient, and the like. In addition, it is preferable that the sum is smaller than the sum of the "volume flow rate of the sludge flow rate" and the "volume flow rate of the raw water flow rate during normal operation when not in the sludge flow". In addition, industrial water or tap water may be used instead of the treatment liquid, but it is preferable to use the treatment liquid or the liquid to be treated in terms of cost.

In the present invention, the flow rate of the treatment liquid or the liquid to be treated introduced into the tank from the introduction pipe is equal to or higher than the flow rate of the sludge discharged from the sludge discharge pipe. It does not occur during sludge discharge.

The sludge withdrawal method may be a continuous method in which the accumulated suspended matter is continuously discharged as sludge from the sludge storage zone, but is preferably an intermittent withdrawal method in which the sludge is intermittently withdrawn. The sludge-like suspended matter that has aggregated and settled to form a mass depends on the properties of the suspended matter, the diameter and shape of the sludge pipe, the friction coefficient of the pipe surface, etc. There is a risk of sedimentation in the tube and blockage. Therefore, a continuous system in which small amounts are constantly discharged is not preferable.

Therefore, in a preferred embodiment of the first invention, an interface meter for detecting an interface between the suspended liquid deposition layer and the liquid to be treated in the coagulation sedimentation tank, and a first interface provided in the inlet pipe. An automatic opening / closing valve, a second automatic opening / closing valve provided in the exhaust pipe, and a control device for controlling the opening / closing of the first and second automatic opening / closing valves in conjunction with the interface detection of the interface meter. .

In this embodiment, the interface between the suspended sediment layer and the liquid to be treated (so-called sludge interface) is detected by the interface meter to have risen to a predetermined upper limit position, and the output signal of the interface meter to that effect is detected. Accordingly, the control device opens the first and second automatic opening / closing valves and discharges the sludge while introducing the processing liquid or the liquid to be processed from the introduction pipe. Next, the interface device detects that the sludge interface has dropped to the predetermined lower limit position, and the control device closes the first and second automatic opening / closing valves based on the output signal of the interface device to that effect, and the processing liquid or the coating solution is removed. Stop the introduction of the treatment liquid and the drainage.

Alternatively, after the control device opens the first and second automatic opening / closing valves, the elapsed time is measured by a timer, and after a predetermined time, the control device causes the first and second automatic opening / closing valves to open. The on-off valve may be closed. In this embodiment,
By providing a control device that adjusts the opening and closing operation of the drainage valve in conjunction with the interface detection by the interface meter, the sludge interface can be maintained within a predetermined range. Thus, it is possible to reliably prevent the flocs separated from the suspended solid deposit layer from entering the contact material accumulation layer.

The configuration of the interface meter is not limited as long as the interface (sludge interface) between the suspended matter deposited layer and the liquid to be treated can be detected. For example, light is incident on the suspension deposit layer and the liquid to be treated thereon, the amount of transmitted light is measured, and a measurement region having a large amount of transmitted light is used as the liquid to be treated. An optical interferometer adapted to detect the interface between the deposited layer and the liquid to be treated can be used. Further, an interface meter using ultrasonic waves, an interface meter using viscosity measurement, or the like may be used.

Another coagulation and sedimentation apparatus according to the present invention (hereinafter referred to as a second invention) is provided with an adding means for adding a coagulant to the liquid to be treated, and provided downstream of the adding means, and is provided with A coagulation sedimentation tank for coagulating and precipitating a suspension, and an apparatus for discharging a treatment liquid having a lower turbidity than the liquid to be treated, wherein the inside of the coagulation sedimentation tank is above a porous partition plate vertically divided In the upper part of the tank, there is a contact material accumulation layer formed by depositing a small piece contact material having a large porosity, and the liquid to be treated is flowed upward in the contact material accumulation layer, and suspended in the liquid to be treated. In the lower part of the tank below the partition plate, there is provided a sludge storage zone for depositing suspended solids, and a sludge pipe for discharging the suspended solids from the sludge storage zone as sludge. In the coagulation sedimentation device, the amount of sludge discharged from the sludge pipe during A treatment liquid storage part capable of storing a treatment liquid equal to or more than the amount of water to be treated to be treated is provided above the coagulation / sedimentation tank above the contact material accumulation layer. The sludge is discharged from the sludge pipe while conducting water to the drainage pipe.

In the present invention, at the time of sludge discharge, the processing liquid corresponding to the sludge flow rate discharged from the sludge pipe flows down naturally from the processing liquid reservoir through the contact material accumulation layer. Does not occur during sludge discharge.

As in the first aspect, in a preferred embodiment of the second aspect, an interface meter for detecting an interface (sludge interface) between the suspended matter deposit layer and the liquid to be treated is provided on the sludge discharge pipe. And a control device for controlling the opening and closing of the automatic opening and closing valve in conjunction with the interface detection of the interface meter.

In the present embodiment, the interface device detects that the interface between the suspension deposit layer and the liquid to be processed has risen to the predetermined upper limit position, and the control device discharges the output signal of the interface device to that effect. Open the automatic on-off valve of the mud pipe. Next, the controller detects that the sludge interface has dropped to the predetermined lower limit position, and the control device uses the output signal of the interface meter to that effect.
Close the automatic on-off valve. Alternatively, the elapsed time may be measured by a timer after the control device opens the automatic on-off valve, and after a predetermined time, the control device may close the automatic on-off valve.

In the first and second inventions, the upper limit position is set to a position below a specific position where the water quality of the treatment liquid is lowered when the suspended solids deposit layer further rises above the specified position. ing. In addition, the lower limit position is set to a position above a specific position where, when the suspended matter sedimentary layer descends further below the specified position, raw water is discharged rather than the suspended matter. In the first and second inventions, even when the amount of suspended solids deposited in the flocculation sedimentation tank is large and it is necessary to frequently remove the suspended liquid, the processing liquid or the liquid to be processed corresponding to the sludge flow rate is removed. By introducing into the coagulation sedimentation tank and preventing the water level in the coagulation sedimentation tank from lowering, the cleaning interval of the contact material accumulation layer provided in the coagulation sedimentation tank is increased, as compared with the conventional coagulation sedimentation apparatus, In addition, the processing liquid having a high liquid quality is stably discharged for a long time, and the liquid quality of the processing liquid is not reduced even when the generated sludge is pulled out.

The liquid to be treated which can be treated by the coagulation / sedimentation apparatus of the present invention is not limited in its source and liquid quality. In particular, the cohesiveness is poor, and it is necessary to add a relatively large amount of inorganic and organic polymer coagulants, so wastewater with a large amount of generated sludge, for example, a relatively high concentration of inorganic components such as power plant comprehensive wastewater It has a great effect when treating wastewater.

[0034]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not limited to these embodiments. Embodiment 1 This embodiment is an example of an embodiment of a coagulation / sedimentation apparatus according to the first invention. FIG. 1 is a schematic diagram showing a main part of the coagulation-sedimentation apparatus of this embodiment, that is, a configuration of a coagulation-sedimentation tank. The coagulating sedimentation apparatus according to the present embodiment employs a water level maintaining / discharging mechanism 68 that prevents the water level in the coagulating sedimentation tank from dropping when the mud is discharged.
The same configuration as that of the conventional coagulation / sedimentation apparatus shown in FIG. Water level maintenance /
As shown in FIG. 1, the sludge discharging mechanism 68 includes a treated water introduction pipe 72.
And the first automatic on-off valve 7 provided in the treated water introduction pipe 72.
4, a treated water pump 76 that pumps treated water from the treated water tank 52 and supplies the treated water to the coagulation sedimentation tank 70 via the treated water introduction pipe 72, an interface meter 78, and a second automatic On-off valve 80, first and second automatic on-off valves 74, 8
And a control device 82 for controlling the opening / closing operation of the zero water and the start / stop of the treated water pump 76.

The treated water introduction pipe 72 is a pipe having an opening below the contact material accumulation layer 44 on the lower outflow prevention plate 40 of the coagulation sedimentation tank 70. The treated water pump 76 introduces treated water having the same flow rate as the sludge discharged from the sludge pipe 60 from the treated water introduction pipe 72 into the tank. The interface meter 78 detects that the interface between the suspended solids layer and the raw water has reached the predetermined upper limit position HL and the predetermined lower limit position LL, respectively, and outputs a signal to that effect to the control device 82. It is a level switch type interface meter. The upper limit position HL is set at a position below the specific position where the quality of the treated water decreases when the suspended solids deposit layer further rises above the specified position.
In addition, the lower limit position LL is set to a position above a specific position where the raw water is discharged rather than the suspended matter when the suspended solids layer falls further below the specified position. As the interface meter 78, for example, a turbidity meter of Central Science Co., Ltd., an optical interface meter of model No. OX100 of Norken Co., Ltd., or the like can be used.

When the interface meter 78 detects that the interface between the suspended sedimentary layer and the raw water has risen to the upper limit position HL, and outputs a signal to that effect to the control device 82, the control device 82 operates the treated water pump 76. And the first and second automatic on-off valves 74,
Release 80. Next, when the sludge is discharged from the sludge pipe 60 and the interface meter 78 detects that the interface has moved down to the lower limit position LL, and outputs a signal to that effect to the control device 82, the control device 82 performs the first and second processes. The second automatic on-off valves 74 and 80 are closed, and the treated water pump 76 is stopped.

In the coagulating sedimentation tank 70 of this embodiment, the suspended matter deposited in the flow of the raw water is automatically discharged as sludge. That is, at the same time as the passage of the raw water, the suspended matter in the raw water starts to coagulate and settle and accumulate in the sludge storage zone 58. Over time, the suspended sediment fills the sludge storage zone 58 and further over the lower outflow prevention plate 40,
The upper limit position HL is reached. When the interface meter 78 detects that the interface between the suspended sedimentary layer and the raw water has risen to the upper limit position HL, it outputs a signal to that effect to the control device 82 and outputs the signal to the control device 82.
2 starts the treated water pump 76 and opens the first and second automatic opening / closing valves 74 and 80. Thereby, the deposited suspended matter starts to be discharged from the sludge pipe 60 as sludge.

With the discharge of the sludge, the interface between the suspended sediment layer and the raw water descends and reaches the lower limit position LL. When the interface meter 78 detects that the interface has dropped to the lower limit position LL, it outputs a signal to that effect to the control device 82, and the control device 82 stops the treated water pump 76 and performs the first and second automatic opening and closing. Valve 7
4. Close 80. Thereby, the sludge is stopped.
In the coagulation / sedimentation tank 70 of the present embodiment, treated water having the same flow rate as the sludge discharge flow rate is introduced by the treated water pump 76 by the above-mentioned water level maintaining / discharging mechanism 68, so that the water level in the coagulation / sedimentation tank 70 is reduced. Without lowering, the interface between the suspended sedimentary layer and the raw water is maintained within the range between the upper limit position HL and the lower limit position LL by monitoring the interface meter 78.
Drainage is performed automatically.

Embodiment 2 This embodiment is an example of an embodiment of a coagulation / sedimentation apparatus according to the second invention. FIG. 2 is a schematic diagram showing a main part of the coagulation-sedimentation apparatus of this embodiment, that is, a configuration of the coagulation-sedimentation tank. The coagulating sedimentation apparatus according to the present embodiment employs a water level maintaining / discharging mechanism 88 that prevents the water level in the coagulating sedimentation tank from dropping when the mud is discharged.
The same configuration as that of the conventional coagulation / sedimentation apparatus shown in FIG.

As shown in FIG. 2, the water level maintaining / discharging mechanism 88 is provided on the treated water reservoir 92 provided in the water collecting zone 36 of the coagulation sedimentation tank 90, the interface meter 94, and the drain pipe 60. The automatic opening / closing valve 96 and a control device 98 for controlling the opening / closing operation of the automatic opening / closing valve 96. Treated water reservoir 9
2 is to store a treated water amount equal to or more than the amount obtained by subtracting the amount of raw water introduced into the coagulation sedimentation tank 90 during the sludge from the amount of the sludge discharged from the sludge pipe 60 during the sludge discharge. It is provided on the upper outflow prevention plate 38 of the coagulation sedimentation tank 90 in combination with the conventional water collecting part 46. The interface meter 94 is the same as the interface meter 78 used in the first embodiment.

The volume of the treated water reservoir 92 is A, the volume from the upper limit position HL to the lower limit position LL in the coagulation sedimentation tank 90 is B, the flow rate of the sludge is f, and the sludge discharge time required for sludge, that is, suspension. If the time required for the material sedimentary layer to decrease from HL to LL is T and the flow rate of raw water is F, T = B / f A ≧ B− (T × F) ≧ B {1− (F / f)} It is. Empirically, in order to efficiently discharge the sludge in the coagulation sedimentation tank 90, the amount of sludge discharged is about half of the coagulation sedimentation volume. Therefore, the volume of the treated water reservoir 92 is preferably about 0.5 to 1 times the volume of the coagulation sedimentation tank 90.

The interface between the suspended sediment layer and the raw water is at the upper limit position H
When the interface meter 94 detects the rise to L and outputs a signal to that effect to the control device 98, the control device 98 opens the automatic on-off valve 96. Next, when the sludge is discharged from the sludge pipe 60 and the suspended solids deposit layer descends and reaches the lower limit LL, the interface meter 94 detects that the interface has descended to the lower limit position LL, and controls a signal to that effect. When output to the device 98, the control device 98 closes the automatic on-off valve 96.

In the coagulating sedimentation tank 90 of the present embodiment, as in the case of the first embodiment, the suspended matter deposited in the flow of the raw water is automatically discharged as sludge. That is, at the same time as the passage of the raw water, the suspended matter in the raw water starts to coagulate and settle and accumulate in the sludge storage zone 58. As time elapses, the suspended sediment layer fills the sludge storage zone 58, and the interface between the suspended sediment layer and the raw water further reaches the upper limit position HL beyond the lower outflow prevention plate 40. When the interface meter 94 detects that the interface has risen to the upper limit position HL, it outputs a signal to that effect to the control device 98, and the control device 98 opens the automatic opening / closing valve 96. Thereby, the deposited suspended matter starts to be discharged from the sludge pipe 60 as sludge. During the sludge discharge, the amount of treated water, which is obtained by subtracting the amount of raw water introduced from the amount of sludge discharged, flows downward from the treated water reservoir 92.
No. 4 is filled with treated water, and the water level does not drop and the water does not run out.

As the sludge is discharged, the interface between the suspended sediment layer and the raw water descends and reaches the lower limit position LL. When the interface meter 94 detects that the interface has dropped to the lower limit position LL, it outputs a signal to that effect to the control device 98, and the control device 98 closes the automatic opening / closing valve 96. Thereby, the sludge is stopped.

In the coagulation sedimentation tank 90 of the present embodiment, the treated water having the same flow rate as the sludge flow rate naturally flows down from the treated water reservoir 92 by the above-mentioned water level maintaining / discharging mechanism 88. The water level in the water deposit 90 does not decrease, and the interface between the suspended sedimentary layer and the raw water is maintained within the range between the upper limit position HL and the lower limit position LL by the monitoring of the interface meter 94, and the sludge is discharged. Is done automatically.

[0046]

According to the first aspect of the present invention, the introduction pipe for introducing the treatment liquid or the liquid to be treated from the outside of the tank at a flow rate equal to or higher than the flow rate of the discharged sludge is provided in the area above the sludge storage zone below the contact material accumulation layer. At the time of sludge discharge, the water level in the coagulation sedimentation tank is increased by introducing sludge from the sludge pipe while introducing the liquid to be coagulated into the coagulation sedimentation tank and introducing the treatment liquid or the liquid to be treated from the introduction pipe. No reduction occurs. Therefore, at the time when the sludge is finished, the liquid quality of the treatment liquid does not deteriorate as in the related art. According to the second aspect of the present invention, the amount of the treated liquid is equal to or greater than the amount obtained by subtracting the amount of the liquid to be treated introduced into the coagulation sedimentation tank during the sludge from the amount of the sludge discharged from the sludge pipe during the sludge. Is provided above the coagulating sedimentation tank above the contact material accumulation layer, and during sludge discharge, sludge is discharged from the sludge pipe while conducting the liquid to be coagulated into the coagulation sedimentation tank. Since the treated water having the same flow rate as the flow rate naturally flows down from the treated water reservoir, the contact material accumulation layer is always filled with the treated water, and the water level does not drop and the drain does not occur. Therefore, at the time when the sludge is finished, the liquid quality of the treatment liquid does not deteriorate as in the related art. By applying the coagulating sedimentation apparatus according to the first and second aspects of the present invention, the introduction of the liquid to be treated can be continued without deteriorating the quality of the treated water even when sludge is extracted. By increasing the washing interval of the lamination, a processing liquid having a high liquid quality can be stably discharged for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a coagulation settling tank according to a first embodiment.

FIG. 2 is a schematic diagram illustrating a configuration of a coagulation sedimentation tank according to a second embodiment.

FIG. 3 is a flow sheet showing the configuration of a conventional upflow coagulation / sedimentation apparatus.

FIG. 4 is a schematic diagram showing a configuration of a coagulation sedimentation tank.

FIG. 5 is a perspective view showing a configuration of a contact material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Conventional upflow coagulation sedimentation apparatus 12 Raw water tank 14 Raw water pump 16A, B Coagulant addition apparatus 18A, B Chemical mixing tank 20 Coagulation sedimentation tank 22 Raw water supply pipe 24 Turbidimeter 26A, B Coagulant tank 28A, B Coagulation Agent pump 29A, B Stirrer 30 Inflow pipe 32 Inflow zone 34 Contact material accumulation zone 36 Water collecting zone 38, 40 Outflow prevention plate 42 Small piece contact material 44 Contact material accumulation layer 45 Flowing area 46 Water collecting section 48 Water collecting trough 50 Outflow Pipe 52 Treated water tank 54 Current transformer plate 56 Alkaline agent injection pipe 58 Sludge storage zone 60 Drainage pipe 62 Air supply pipe 64 Air blower 68 Water level maintenance / discharge mechanism 70 Coagulated sedimentation tank of Embodiment 1 72 Treated water introduction pipe 74 First automatic on-off valve 76 Treated water pump 78 Interface meter 80 Second automatic on-off valve 82 Control device 88 Water level maintenance / sludge mechanism 90 Coagulation sedimentation tank of Embodiment 2 92 Treated water reservoir 94 Interface meter 96 Automatic on-off valve 98 Control device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01D 21/24 B01D 21/24 T 21/30 21/30 G J 24/02 C02F 1/52 E 24 / 00K C02F 1/52 B01D 23/10 C 29/08 530C 540A F term (reference) 4D015 BA22 BB12 CA01 CA20 DA04 DB12 EA32 EA35 FA01 FA02 FA15 FA26 FA28 4D041 BA21 BB01 BC02 BD11 CB04 4D062 BA22 BB12 CA01 CA20 DA04 DB12 FA01 FA02 FA15 FA26 FA28

Claims (4)

[Claims] 1. An apparatus comprising: an adding means for adding a flocculant to a liquid to be treated; and an aggregating and settling tank provided downstream of the adding means for coagulating and precipitating a suspension in the liquid to be treated. This is a device that discharges a processing liquid with lower turbidity than the liquid, and a contact formed by depositing a small porosity small piece contact material on the upper part of the tank above the porous partition plate dividing the coagulation sedimentation tank up and down The material to be treated has a material accumulation layer, and the liquid to be treated is caused to flow upward in the contact material accumulation layer to aggregate and precipitate the suspension in the liquid to be treated, and to precipitate at the lower part of the tank below the partition plate. In a coagulation and sedimentation apparatus provided with a sludge storage zone for depositing suspended matter and a sludge pipe for discharging suspended matter deposited from the sludge storage zone as sludge, the sludge storage zone is provided below the contact material accumulation layer. In the area of, there is an introduction pipe for introducing the processing liquid or the liquid to be treated from outside the tank at a flow rate higher than the flow rate of the sludge. A coagulation sedimentation apparatus which discharges sludge from a drainage pipe while introducing liquid to be treated into a coagulation sedimentation tank and introducing treatment liquid or liquid to be treated through an inlet pipe during mud. 2. An interface meter for detecting an interface between a sedimentary layer of a suspended solid and a liquid to be treated in a coagulation sedimentation tank, a first automatic opening / closing valve provided on an inlet pipe, and a mud pipe. 2. The control device according to claim 1, further comprising a second automatic on-off valve, and a control device that controls opening and closing of the first and second automatic on-off valves in conjunction with interface detection by an interface meter. Coagulation sedimentation equipment. 3. An apparatus comprising: an adding means for adding an aggregating agent to a liquid to be treated; and an aggregating and settling tank provided downstream of the adding means for aggregating and precipitating a suspension in the liquid to be treated. This is a device that discharges a processing liquid with lower turbidity than the liquid, and a contact formed by depositing a small porosity small piece contact material on the upper part of the tank above the porous partition plate dividing the coagulation sedimentation tank up and down The material to be treated has a material accumulation layer, and the liquid to be treated is caused to flow upward in the contact material accumulation layer to aggregate and precipitate the suspension in the liquid to be treated, and to precipitate at the lower part of the tank below the partition plate. In a coagulation and sedimentation device equipped with a sludge storage zone for depositing suspended matter and a sludge pipe for discharging the suspended matter deposited from the sludge storage zone as sludge, the sludge is discharged from the sludge pipe Store the processing liquid equal to or greater than the amount of sludge minus the amount of liquid to be treated that is introduced into the coagulation sedimentation tank. A coagulation sedimentation tank is provided above the coagulating sedimentation tank above the contact material accumulation layer, and when sludge is discharged, sludge is discharged from the sludge pipe while the liquid to be treated is introduced into the coagulation sedimentation tank. apparatus. 4. An interface meter for detecting an interface between a sedimentary layer of suspended matter and a liquid to be treated in a coagulation sedimentation tank, an automatic open / close valve provided in a drain pipe, and an open / close valve for automatic open / close valve. 4. A control device for controlling in conjunction with said interface detection.
3. The coagulation sedimentation apparatus according to 1.