JP5931546B2 - Muddy water filtration method and muddy water filtration apparatus - Google Patents

Description

  This invention sinks a filter plate in a filter tank supplied with muddy water such as tunnel waste water or mixer car washing water generated at a tunnel excavation work site, etc., and suspended matter in the muddy water is formed on the surface of the filter cloth forming the filter plate. The present invention relates to a turbid water filtration method and a turbid water filtration device, in which a turbid water is dynamically filtered through the precoat layer after a precoat layer is formed using the.

  Clay-mixed turbid water generated at tunnel excavation work sites and dam construction sites cannot be discharged into rivers as they are, and was discharged after coagulation sedimentation treatment. In this coagulation sedimentation treatment, the composition variation of turbid water is large, it is difficult to control the amount of coagulation to be added, and since the coagulant is used, the environment may be adversely affected.

  For this reason, there is one that performs dynamic filtration by membrane separation instead of coagulation sedimentation (see Patent Document 1). In dynamic filtration, turbid water is filtered using a non-woven membrane. Particle components in turbid water are deposited on the membrane to form a dynamic layer (precoat layer). It is something to process.

Japanese Patent No. 4359025

  By the way, when a precoat layer is formed on the filter cloth surface of the filter body using a suspended substance in the muddy water and the muddy water is dynamically filtered, the muddy water is mixed with a flocculant and suspended in the filtration tank. There is a problem that the substance precipitates at a high speed, it takes time to form the precoat layer, and the entire filtration treatment efficiency is lowered.

  This invention is made | formed in view of the above, Comprising: It aims at providing the muddy water filtration method and muddy water filtration apparatus which can perform the formation of a precoat layer rapidly and can improve filtration process efficiency.

To solve the above problems and achieve the object, turbid water filtration method according to the present invention, the filter cloth surfaces submerged plurality of filter plate to the filtration tank in which turbid water is Ru is supplied, to form a respective filter plate after respectively forming the precoat layer by attaching suspended solids in turbid water to, while a turbid water filtration method of dynamically filtering the turbid water using each of the precoat layer to diffuse suspended solids in the filter tank each Forming step of forming each precoat layer on the surface of each filter cloth by suction from the inside of the filter cloth , and subsequent to the forming step, filtering step of filtering muddy water using each precoat layer by suction from the inside of each filter cloth And a backwashing step in which each precoat layer whose filtration function has been lowered due to the passage of a predetermined filtration time is peeled off by supplying water inside each filter cloth. The backwashing process is performed at the timing when the whole is divided into a plurality of parts and sequentially executed for each of the plurality of parts by a submerged peeling method, and the backwashing process is executed for a predetermined part of the filter plate. The forming step or the filtering step is performed on the portion of the filter plate that has not been executed .

  Further, in the turbid water filtration method according to the present invention, in the above invention, the turbid water supplied to the filtration tank is added with a pH adjusting agent and a flocculant before being supplied to the filtration tank, It is added only when the precoat layer is formed.

  The muddy water filtration method according to the present invention is characterized in that, in the above invention, a diffusion pump is provided in the lower part of the filter plate, and the turbid water in the lower part of the filter plate sucked by the diffusion pump is diffused from the upper part of the filter plate. .

  The muddy water filtration method according to the present invention is characterized in that, in the above invention, the muddy water diffused from the upper part of the filter plate is discharged in a direction parallel to the filter cloth surface between the filter plates. To do.

  Further, in the muddy water filtration method according to the present invention, in the above invention, stirring means is provided at the lower part of the filter plate, and the flow of muddy water stirred by the stirring means is in a direction parallel to the filter cloth surface. Features.

Further, turbid water filtration device according to this invention, submerged plurality of filter plate to the filtration tank which turbid water is Ru are supplied, respectively, deposited suspended matter in turbid water to each filter cloth surface to form a respective filter plate after forming the precoat layer, a turbid water filtration device for dynamic filtration of turbid water using each of the pre-coat layer, a diffusion means for diffusing turbid water in the filter tank during the formation process for forming a respective precoat layers, Each of the filter cloths is connected to a plurality of filter plates, and in each filter cloth, after the formation process, a filtration process for filtering turbid water using each precoat layer by suction from the inside of each filter cloth, and the passage of a predetermined filtration time Each precoat layer with a reduced filtration function can be separated by supplying water into each filter cloth to separate the backwash process, and the backwash process is filtered. Backwash process at the timing when the whole is divided into a plurality of parts and sequentially executed for each of the plurality of parts by submerged peeling method, and the backwash process is executed for a predetermined part of the filter plate. And a control means for executing the forming process or the filtering process on the portion of the filter plate not performing the process .

  In the turbid water filtration device according to the present invention, in the above invention, a mixing tank for adding a pH adjusting agent and a flocculant to mix with the turbid water is provided in the preceding stage of the filtration tank, and the control means includes the flocculant Is added to the mixing tank only when the precoat layer is formed.

  Moreover, in the turbid water filtration device according to the present invention, in the above invention, the diffusing means is provided with a diffusion pump in the lower part of the filter plate, and diffuses turbid water in the lower part of the filter plate sucked by the diffusion pump from the upper part of the filter plate It is characterized by that.

  The turbid water filtration device according to the present invention is characterized in that, in the above invention, the turbid water diffused from the upper part of the filter plate is discharged in a direction parallel to the filter cloth surface between the filter plates. To do.

  In the turbid water filtration device according to the present invention, in the above invention, the diffusing means is a stirring means provided at a lower part of the filter plate, and the stirring means is arranged in a direction parallel to the filter cloth surface. The flow is formed.

  According to the present invention, the filter plate is submerged in a filtration tank supplied with muddy water, and the precoat layer is formed on the surface of the filter cloth forming the filter plate using the suspended substance in the muddy water. In the turbid water filtration method for dynamically filtering the turbid water, the turbid water in the filtration tank is diffused when the precoat layer is formed. Even if it exists, formation of a precoat layer can be performed rapidly and the filtration processing efficiency can be improved as a result.

FIG. 1 is a schematic diagram showing the configuration of a turbid water filtration device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a mud submerging process by the muddy water filtering device shown in FIG. FIG. 3 is a time chart showing a muddy water filtration process by the muddy water filtration apparatus shown in FIG. FIG. 4 is a perspective view showing the configuration of the diffusing means of the muddy water filtering device shown in FIG. FIG. 5 is a diagram illustrating an example of a turbidity time change between the raw water and the filtrate by the turbid water filtration device illustrated in FIG. 1. FIG. 6 is a schematic diagram showing another example of the diffusing means.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

(overall structure)
FIG. 1 is a schematic diagram showing the configuration of a turbid water filtration device according to an embodiment of the present invention. As shown in FIG. 1, this muddy water filtration apparatus 1 adjusts the pH of raw water tank 2 to which muddy water D1 such as tunnel waste water to be filtered and mixer car washing water is supplied, and pH adjustment of muddy water D1 supplied from the raw water tank 2. Supplied from the mixing tank 3 into which carbon dioxide (CO ₂ ) for injection is injected, the mixing tank 4 in which PAC (polyaluminum chloride) as a coagulant is injected into the turbid water D2 overflowed from the mixing tank 3, and the mixing tank 4 The turbid water D3 is collected, and the turbid water D3 is filtered by a plurality of filter plates 50, and the filtered water D4 filtered by the filtering tank 5 and the filtering tank 5 that produces a concentrated slurry is filtered through the header tank 6 and the vacuum pot 7. Filtered water tank 8 for temporarily storing water, treated water tank 9 for storing filtered water D6 supplied from the filtered water tank 8, and concentrated slurry for temporarily storing concentrated slurry D8 supplied from the filter tank 5 Having a control unit C for controlling the entire vessel 10, and muddy water filtration device.

  As described above, the raw water tank 2 is supplied with the turbid water D1 and temporarily stored, and the turbid water D1 temporarily stored is mixed through the pipe 61 provided with the filter 31 at the tip and the raw water pump 11 in the middle. Supply to tank 3. A pH sensor 21 that detects the pH of muddy water is provided in the middle of the pipe 61, and the detection result is sent to the control unit C. A flow meter 24 is provided in the middle of the pipe 61, and the detection result is sent to the control unit C. The control unit C controls the raw water pump 11 based on the flow rate detected by the flow meter 24. Further, the turbid water D3 overflowed in the filtration tank 5 is returned to the raw water tank 2.

The mixing tank 3 is supplied with CO ₂ being bubbled through a valve 41 and a flow meter 25 from a CO ₂ cylinder or the like. CO ₂ is a neutralizing agent that adjusts the pH of the turbid water D1 to 6.5 or less. When the pH detected by the pH sensor 21 is 7 or more, CO ₂ is injected and the pH is 6.5. Stop infusion if: The mixing tank 3 is provided with a stirrer 32 to promote neutralization.

  The mixing tank 4 is supplied with PAC via the pump 12 and the flow meter 26. This PAC is a flocculant and is supplied only when the precoat layer is generated, as will be described later. This supply control is performed by driving control of the pump 12 by the control unit C. The mixing tank 4 is provided with a stirrer 33 to promote aggregation. A pipe 68 and valves 45 and 46 are provided at the lower portions of the mixing tanks 3 and 4, and by opening the valves 45 and 46, the turbid substance precipitated in each tank flows out to the concentrated slurry tank 10. be able to.

  The filtration tank 5 stores the turbid water D3 supplied from the mixing tank 4, and the turbid water D3 is filtered by the suction force of the vacuum pot 7 through the filter plate 50 submerged in the tank. The vacuum pot 7 is evacuated by the vacuum pump 15 and set to a vacuum state of, for example, about −0.025 MPa, and the negative pressure causes the turbid water outside the filter plate 50 to be suction filtered. The filtration treatment is preferably performed by continuous suction, and it is desirable to provide a plurality of vacuum pots 7 and alternately perform suction. The filtered water D4 is supplied to the filtered water tank 8 through the header pipe 51, the header tank 6, and the vacuum pot 7. A plurality of filter plates 50 are provided, and the surfaces of the filter plates 50 are arranged at predetermined pitch intervals.

  The filter plate 50 has a filter cloth 50a stretched by an elastic member in a rectangular filter frame. The filter cloth 50a is a bag formed of a woven cloth, a non-woven cloth, a metal net, or the like, and a spacing member is disposed between two closed filter cloths as necessary. As shown in FIG. 2, when the filtration process is performed, a precoat layer 50b in which a turbid water turbid substance is deposited is formed on the surface of the filter cloth 50a, and the fine gaps and holes formed by the precoat layer 50b are passed through. To produce filtered water. The filtered water D5 sucked by the vacuum pot 7 is supplied to the filtered water tank 8 through the pipe 65 by opening the valve 44.

  Here, the filtration tank 5 has a turbid water diffusion means in order to quickly generate the precoat layer when the precoat layer 50b is generated. This diffusion means operates only when the precoat layer is generated, and diffuses the turbid material so that the turbid material in the turbid water is uniformly distributed. The reason why this diffusion treatment is performed is that turbid water to which a flocculant such as PAC is added precipitates and it is difficult to form a precoat layer. Although details will be described later, a diffusion pump 16 is provided at the lower part of the filtration tank 5, and the turbid water sucked by the diffusion pump 16 is conveyed to the upper part of the filtration tank 5 through the diffusion pipe 17, and the diffusion trough 18. Discharged inside. A discharge notch is provided in the longitudinal direction of the diffusion trough 18, and turbid water overflows from the notch so as to be uniformly dispersed and dropped on the upper part of the filtration tank 5. Then, the dropped turbid water settles again in the turbid water together with the suspended matter. By providing such a diffusing means, the suspended substance in the muddy water is uniformly distributed in the muddy water, and as a result, the precoat layer is rapidly formed. In addition, if a precoat layer is not formed in a part of filter cloth surface, filtered water with low turbidity cannot be obtained.

The filtered water tank 8 includes a pH sensor 22, a turbidimeter 23, and a pump 14. When the turbidity is equal to or higher than the predetermined value, the control unit C sucks the turbidity by the pump 14 and returns it to the filtration tank 5 as filtered water D7. Further, the controller C opens the valve 47 to inject CO ₂ when the pH is 7 or more, and stops injecting CO ₂ when the pH is 6.5 or less. Therefore, when the turbidity is less than the predetermined value, the filtered water D5 is discharged to the treated water tank 9 as filtered water D6 via the pipe 66, and then released to a river or the like.

(Outline of filtration treatment)
As shown in FIG. 2, turbid water is continuously supplied from the mixing tank 4 to the filtration tank 5. Then, the precoat layer 50b is generated prior to the start of the filtration treatment operation (see FIGS. 2A to 2B). Thereafter, the turbid water is continuously filtered by the suction force of the vacuum pot 7. In addition, the thickness of the precoat layer 50b is 10 mm or less, and the solid content beyond it settles without adhering to a filter cloth. Moreover, many substances adhering to the filter cloth are derived from cement such as calcium. Since the precoat layer 50b has a filtration efficiency that decreases due to clogging or the like with the lapse of time of the filtration process, the valve 43 on the pipe 63 is closed and the valve 42 is opened, so that the inside of the filter cloth is connected through the pipe 62. The precoat layer 50b is peeled off in the liquid by backwashing with water (see FIG. 2C). Thereafter, the screw pump 13 provided at the lower part of the filtration tank 5 is driven, and the precoat layer 50b accumulated at the lower part of the filtration tank 5 is discharged as a concentrated slurry to the concentrated slurry tank 10 via the pipe 67 (FIG. 2D). reference). At the same time, the valve 42 is closed, the valve 43 is opened, and the precoat layer 50b is formed (see FIG. 2 (d) → (a) → (b)). Then, the filtration process is performed again. The concentrated slurry at the bottom of the filtration tank 5 includes precipitated flocks and the like. The concentrated slurry tank 10 is provided with a stirrer 34 so as to maintain a slurry state. Further, the concentrated slurry accumulated in the concentrated slurry tank 10 is then backfilled with a dehydrated cake generated by a dewatering facility such as a screw press.

  Such a filtration process is called a submerged peeling method, and a continuous filtration process by continuously supplying muddy water can be performed using the precoat layer 50b once generated. Moreover, the continuous concentrated slurry can be discharged. In the normal peeling method, when peeling the precoat layer, in order to expose the filter plate 50 from turbid water, it is necessary to discharge and supply turbid water in the filtration tank 5, but this in-liquid peeling is performed. In the system, since it is not necessary to perform such muddy water discharge processing and supply processing, substantial filtration processing efficiency can be increased.

(Filtration processing control)
FIG. 3 is a time chart showing a muddy water filtration process procedure by the control unit C. As shown in FIG. 3, when the operation of the turbid water filtration process is started (time point t0), the control unit C first drives the diffusion pump 16 to preliminarily remove suspended substances in the turbid water in the filtration tank 5. Let it diffuse. This diffusion treatment is performed until time t2 when the precoat layer 50b is formed. Thereafter, at time point t1, for example, when a time of about 10 minutes during which the suspended substances in the muddy water are almost diffused, the control unit C drives the raw water pump 11 to supply muddy water to the filtration tank 5. Further, in the mixing tanks 3 and 4, CO ₂ and PAC are mixed with turbid water, respectively. Further, the vacuum pump 15 is driven, the vacuum pot 7 is set to a negative pressure via the pipe 64, and filtered water is sucked through the header pipe 51 (51a, 51b). The time from time t0 to time t1 is a time for forming the precoat layer 50b. The determination as to whether or not the precoat layer 50b has been formed is when the turbidity detected by the turbidimeter 23 is substantially 0, for example, 5 or less (see FIG. 3 (h)). In practice, the time during which the precoat layer 50b is formed is empirically obtained in advance, and at the time t2 when this time has elapsed, the diffusion pump 16 is stopped and the supply of PAC is stopped. The time between the time points t1 and t2 is, for example, 1 hour.

  Thereafter, the concentrated slurry is discharged by driving the screw pump 13 periodically from time t2 to time t3 (see FIG. 3 (f)). The time from time t2 to time t3 is, for example, 24 hours.

When reaching the time point t3, the precoat layer 50b is peeled off. This is because, when the precoat layer 50b is used for about 24 hours, the filtration function of the precoat layer 50b itself is lowered, and the filtration performance per unit time is lowered. The peeling process of the precoat layer 50b is sequentially performed for each of the header tubes 51a and 51b. The header pipes 51a and 51b are shown as examples connected to a plurality of header tanks 6, respectively. Each header pipe 51 is connected to a predetermined number of filter plates 50. In FIG. 3, when the precoat layer 50b of the filter plate 50 connected to the header pipe 51a is peeled off, the backwashing process for supplying water to the header pipe 51a without stopping the suction of the header pipe 51a and performing the filtration process is performed. Do. The backwashing process time of the header pipe 51a (t3 to t4) and header pipes 5 1 b backwash processing time (t4 to t5) is, for example, each about 2 minutes. The peeling pressure is about 0.05 to 0.2 MPa.

  At the same time as the backwashing process, the precoat layer 50b is formed during the period from the time t3 to the time t6, similarly to the time t1 to t2. Also in this case, the turbid water diffusion process and the PAC supply process are performed only between time points t3 and t6. Then, after time t6, the filtration process using the formed precoat layer 50b is continuously performed, for example, for about 24 hours, similarly to time t2 and thereafter. In addition, although the diffusion process is performed from the time t0 when the operation is started, the diffusion process may be performed from the time t1. Of course, it is preferable to perform the diffusion treatment from the time t0 when the operation is started because the precoat layer 50b is formed quickly.

(Details of diffusion means)
As shown in FIG. 4, the diffusion trough 18 is arranged on the upper part of the filtration tank 5, is orthogonal to the filter plate 50, and is provided horizontally at the upper center of the filter plate 50. The diffusion pump 16 disposed at the lower portion of the filtration tank 5 injects the sucked turbid water from one end of the diffusion trough 18 through the diffusion pipe 17. A plurality of pairs of cutouts 18 a are formed on the upper ends of both side portions of the diffusion trough 18 so as to correspond to the pitch of the filter plate 50. The notch 18 a is located at the approximate center between the filter plates 50. Therefore, the muddy water poured into the diffusion trough 18 spills almost uniformly on the upper surface of the filtration tank 5 and between the filter plates 50. As a result, the turbid water existing in the lower part of the filtration tank 5 is uniformly diffused in the upper part of the filtration tank 5, and the direction of the spilled turbid water circulates in a plane parallel to the surface of the filter plate 50. It becomes easier to diffuse. Further, the spilled turbid water does not directly hit the filter plate 50, and therefore does not hinder the formation of the precoat layer 50b. Further, since this muddy water is dispersed and does not settle in one direction, the solid content is not unevenly attached in the filtration tank 5. From this point of view, it is preferable to inject turbid water or filtered water supplied from the mixing tank 4 or the filtered water tank 8 through the diffusion trough 18.

(Filtering result)
FIG. 5 is a diagram showing the turbidity change of the turbid water and filtered water obtained by the turbid water filtration device shown in FIG. FIG. 5 shows the turbidity change for about 10 hours. As a result, even when the turbidity of the turbid water was large and violently changed to 200 to 3000 or more, the turbidity of the filtered water could be suppressed to 5 or less. That is, it was possible to form the precoat layer 50b in a short time of about 1 hour and to confirm that this precoat layer 50b has a sufficient filter effect.

(Modification of diffusion means)
In the above-described embodiment, the turbid water is diffused using the diffusion trough 18, but as shown in FIG. 6, in this modified example, the stirrer 60 is provided at the lower part of the filtration tank 5 to circulate the turbid water. By spreading the suspended matter in the turbid water. The direction of circulation of the muddy water is set to be in a plane parallel to the surface of the filter plate 50. Although this stirrer 60 rotates a fan with a motor, it is not restricted to this, What is necessary is just what produces a water flow, For example, the submersible pump which produces a water flow may be sufficient. Further, a circulating water flow may be generated by generating bubbles.

(Other variations)
The diffusion trough 18 is not limited to the diffusion trough 18 described above, and any diffusion means that can be dispersed may be used. Further, the diffusion trough 18 may not be provided at the center.

  Furthermore, in the above-described embodiment, vacuum suction is used. However, the present invention is not limited to this, and a siphon filtration method may be used. Note that the vacuum suction can shorten the piping and is not affected by the pH, so that the piping life can be extended.

DESCRIPTION OF SYMBOLS 1 Turbid water filtration apparatus 2 Raw water tank 3, 4 Mixing tank 5 Filtration tank 6 Header tank 7 Vacuum pot 8 Filtration water tank 9 Treated water tank 10 Concentrated slurry tank 11 Raw water pump 12, 14 Pump 13 Screw pump 15 Vacuum pump 16 Diffusion pump 17 Diffusion Piping 18 Diffusion trough 18a Notch 21, 22 pH sensor 23 Turbidimeter 24-26 Flow meter 31 Filter 32-34, 60 Stirrer 41-47 Valve 50 Filter plate 50a Filter cloth 50b Precoat layer 51 Header pipe 61- 68 Piping C Controller

Claims (10)

A plurality of filtration plates are submerged in a filtration tank to which turbid water is supplied, and each pre-coat layer is formed by attaching suspended substances in the turbid water to the respective filter cloth surfaces forming the respective filtration plates. A turbid water filtration method of dynamically filtering the turbid water using a precoat layer of
A diffusion step of circulating turbid water in the filtration tank and diffusing suspended substances in the filtration tank while stopping suction from the inside of each filter cloth;
The Following diffusion process, the while turbid water in the filter tank is circulated by diffusing suspended solids in said filter tank, wherein the respective precoat layers to each filter cloth surface by suction from inside the filter cloth Forming step of forming,
Subsequent to the forming step, a filtration step of filtering muddy water using the respective precoat layer by suction from the inside of each filter cloth,
A backwashing step of peeling off each precoat layer whose filtration function is reduced by the passage of a predetermined filtration time by supplying water into each filter cloth,
The back washing step divides the entire filter plate into a plurality of parts, and sequentially executes each of the plurality of parts by a submerged peeling method, and the back wash with respect to a predetermined part of the filter plate. The muddy water filtration method, wherein the forming step or the filtration step is performed on a portion of the filter plate that is not performing the backwashing step at a timing of performing the step. Before the turbid water supplied to the filtration tank is supplied to the filtration tank, a pH adjusting agent and a flocculant are added, and the pH adjusting agent is added in the forming step, the filtering step, and the backwashing step. The flocculating water filtration method according to claim 1 , wherein the flocculant is added only to the forming step . The diffusing step and the forming step are characterized in that the turbid water in the lower portion of the filter plate in the filter tank and sucked by the diffusion pump provided in the lower portion of the filter plate is discharged from the upper portion of the filter plate. Or the muddy water filtration method of 2.   The muddy water diffusing from the upper part of the filter plate is discharged between the filter plates in a direction parallel to the filter cloth surface.   The turbid water filtration method according to claim 1 or 2, wherein a stirring means is provided at a lower part of the filter plate, and the flow of turbid water stirred by the stirring means is in a direction parallel to the filter cloth surface. A plurality of filtration plates are submerged in a filtration tank to which turbid water is supplied, and each pre-coat layer is formed by attaching suspended substances in the turbid water to the respective filter cloth surfaces forming the respective filtration plates. A turbid water filtration device that dynamically filters the turbid water using a precoat layer of
While the suction from the inside of each filter cloth is stopped, the turbid water in the filtration tank is circulated to disperse the suspended substances in the filtration tank, and then, during the forming process of forming the respective precoat layers A diffusion means for circulating the turbid water in the filtration tank to diffuse the turbid water in the filtration tank;
Each of the filter plates connected to each of the plurality of filter plates, and in each of the filter cloths, a filtration process for filtering muddy water using the respective precoat layers by suction from the inside of each of the filter cloths following the formation process; A header tube capable of performing backwashing treatment by peeling off each of the precoat layers whose filtration function has been lowered due to the passage of filtration time by supplying water inside each filter cloth;
The backwashing process is performed on each of the plurality of parts in order by dividing the entire filter plate into a plurality of parts by a submerged peeling method, and the backwashing is performed on a predetermined part of the filter plate. Control means for executing the forming process or the filtering process on the part of the filter plate not performing the backwash process at the timing of performing the process;
A turbid water filtration device characterized by comprising: A mixing tank for adding a pH adjusting agent and a flocculant to mix with turbid water is provided in the preceding stage of the filtration tank, and the control means is configured to add the pH adjusting agent during the formation of the precoat layer, during the filtration process, and The turbid water filtration device according to claim 6 , wherein the flocculant is added at the time of the backwashing treatment, and the flocculant is added to the mixing tank only at the time of forming the precoat layer. The diffusion means includes a diffusion pump in the lower part of the filter plate in the filter tank, and discharges muddy water in the lower part of the filter plate sucked by the diffusion pump from the upper part of the filter plate. The muddy water filtration apparatus according to 7.   The turbid water filtration device according to claim 8, wherein the turbid water diffused from the upper part of the filter plate is discharged in a direction parallel to the filter cloth surface between the filter plates.   The said diffusion means is a stirring means provided in the said filtration board lower part, The said stirring means forms the flow of the muddy water in the direction parallel to the said filter cloth surface, The Claim 6 or 7 characterized by the above-mentioned. The muddy water filtration apparatus as described.

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