JP2008043911A - Sludge thickening apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge thickening apparatus which can reduce an installation space by compacting it and prevent destruction and clogging of a sludge flock by eliminating pipes for connecting a sludge flocculation tank and a thickener. <P>SOLUTION: The sludge thickening apparatus including the thickener 1 comprises containing a filtration cylinder 3 in the sludge flocculation tank 21 agitating sludge loaded with a flocculant by an agitator 24 to make a flock and an external cylinder 2, rotatably containing a spiral screw 4 inside the filtration cylinder 3, passing a moisture contained in the sludge through the filtration surface 3a of the filtration cylinder 3, discharging it from a separated liquid discharge pipe 11 as a separated liquid and thickening the sludge while conveying the sludge introduced from the sludge flocculation tank 21 into the bottom in the filtration cylinder 3 upward by rotationally driving the spiral screw 4, and discharging thickened sludge from the top of the filtration cylinder 3, wherein the thickener 1 is directly connected and placed on the sludge flocculation tank 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sludge aggregating tank and a sludge concentrating device including a concentrator for concentrating the sludge flocked in the sludge aggregating tank.

  In order to discard or incinerate various types of sludge, the sludge is dehydrated with a dehydrator. However, it is difficult to efficiently dehydrate sludge only with the processing capacity of the dehydrator. For this reason, prior to the dewatering treatment by the sludge dewatering machine, the sludge is agglomerated with a flocculant to form a floc, and the water is separated from the flocked sludge (aggregated sludge) to concentrate the sludge. Various sludge concentrators for implementing this have been proposed and put to practical use.

  By the way, the sludge concentrating device is roughly classified into a rotary screen type and a screw press type. FIG. 2 shows an example of a screw press type sludge concentrating device (see, for example, Patent Documents 1 and 2).

  That is, FIG. 2 is a schematic diagram showing a basic configuration of a conventional sludge concentrating device. The sludge concentrating device shown in the figure includes a concentrator 1 and a sludge aggregating tank 21, and sludge to which a flocculant is added is sludge agglomerated. The tank 21 is flocked and the flocated sludge is concentrated by the concentrator 1.

  The sludge agglomeration tank 21 is a cylindrical tank-like container having an open upper surface, and a raw mud supply pipe 22 is connected to the lower part thereof. In the sludge aggregation tank 21, a stirrer 24 that is driven to rotate by a motor 23 is provided.

  The concentrator 1 has a cylindrical filter tube 3 disposed in a vertical direction inside a cylindrical tank-shaped outer tube 2 having a sealed structure, and a spiral screw 4 is rotatably accommodated in the filter tube 3. Configured.

  Here, the peripheral surface of the portion of the filtration cylinder 3 facing the outer cylinder 2 constitutes a filtration surface 3a made of a punching plate, a wedge wire, or the like, and the screw conveyor 5 is horizontally disposed above the filtration cylinder 3. The agglomerated sludge introduction pipe 6 led out from the upper part of the sludge agglomeration tank 21 is connected to the lower part of the filter cylinder 3. Here, the screw conveyor 5 is configured such that a screw 5b that is rotationally driven by a motor 7 is accommodated in a cylindrical housing 5a, and a concentrated sludge discharge pipe 8 is directed downward in the lower part of the housing 5a. Derived.

  Separately, the separated liquid take-out pipes 9 and 10 are led out from the upper and lower sides of the outer cylinder 2, and these separated liquid take-out pipes 9 and 10 are connected to an inverted U-shaped separated liquid discharge pipe 11. Yes.

  The spiral screw 4 is configured by spirally winding a screw blade 4b around a rotating shaft 4a, and a motor 12 as a drive source is connected to the rotating shaft 4a. The outer diameter of the spiral screw 4 is set slightly smaller than the inner diameter of the filtration surface 3a of the filter cylinder 3, and a small gap is formed between the outer peripheral edge of the spiral screw 4 and the filtration surface 3a of the filter cylinder 3. Is formed.

  Thus, sludge (raw mud) is supplied from the raw mud supply pipe 22 to the sludge agglomeration tank 21, and a flocculant such as a polymer is added to the sludge flowing through the raw mud supply pipe 22, and the flocculant is added. The sludge thus produced is agitated by the agitator 24 in the sludge agglomeration tank 21, and the sludge is flocked by aggregating solid components contained therein.

  Aggregated sludge in the sludge aggregation tank 21 is introduced into the filter cylinder 3 of the concentrator 1 from the lower part through the aggregated sludge introduction pipe 6.

In the concentrator 1, the spiral screw 4 is rotationally driven by the motor 12 at a predetermined speed in the filter cylinder 3, and the coagulated sludge introduced into the lower part of the filter cylinder 3 is moved upward by the rotating spiral screw 4. In addition, the water contained therein passes through the filtration surface 3a of the filtration cylinder 3 and is stored in the outer cylinder 2 as a separation liquid. Here, since the water level h ₂ of the separation liquid in the separation liquid discharge pipe 11 is set lower than the liquid level h ₁ in the filter tube 3 (h ₂ <h ₁ ), both h ₁ and h _2. Difference (head difference) Δh ₁₂ (= h ₁ −h ₂ ) as a filtration pressure, moisture separated from the coagulated sludge passes through the filtration surface 3a of the filtration cylinder 3 and is separated into the outer cylinder 2 Housed as a liquid. In this case, since the outer cylinder 2 is disposed below the water level h _{2 of the} separation liquid, the separation liquid accommodated in the outer cylinder 2 is filled in the outer cylinder 2 and is contained in the separation liquid. The filtration surface 3a of the filtration cylinder 3 will be buried.

The separation liquid stored in the outer cylinder 2 flows into the separation liquid discharge pipe 11 from the separation liquid extraction pipes 9 and 10 connected to the upper and lower sides of the outer cylinder 2 and is discharged to the outside. In addition, the aggregated sludge conveyed upward in the filter cylinder 3 by the rotation of the spiral screw 4 is concentrated by separating the water in the middle thereof to become concentrated sludge. This concentrated sludge is filtered by the screw conveyor 5. It is discharged from the upper part of the cylinder 3 to the outside and supplied from the concentrated sludge discharge pipe 8 to a dehydrator (not shown) for dehydration.
Japanese Patent No. 3627809 JP 2006-0775675 A

  However, in the conventional sludge concentrating device shown in FIG. 2, the concentrator 1 and the sludge agglomeration tank 21 are configured independently and are spaced apart from each other. The coagulated sludge introduction pipe 6 for connecting the pipes becomes long, and there is a problem that the flocs of the sludge flowing inside the pipe may be broken or clogged in the middle.

  The present invention has been made in view of the above problems, and its intended process is to reduce the installation space by reducing the size of the sludge and eliminate the piping connecting the sludge agglomeration tank and the concentrator. An object of the present invention is to provide a sludge concentrating device capable of preventing the occurrence of clogging and clogging of flocs.

In order to achieve the above object, the invention according to claim 1
A sludge agglomeration tank in which the sludge to which the flocculant is added is agitated with a stirrer to flocate,
A filtration cylinder is accommodated in the outer cylinder, a spiral screw is rotatably accommodated in the filtration cylinder, and the spiral screw is rotationally driven to be introduced into the lower part of the filtration cylinder from the sludge aggregation tank. While conveying the sludge upward, the water contained in the sludge passes through the filtration surface of the filter cylinder and is discharged as a separation liquid from the separation liquid discharge pipe to concentrate the sludge, and the concentrated sludge is filtered. A concentrator that discharges from the top of the tube;
In the sludge concentrator equipped with
The concentrator is directly connected to the sludge aggregation tank.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the sludge concentrated by the concentrator is discharged from the upper part of the filter cylinder by a screw conveyor.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the agitator of the sludge agglomeration tank and the spiral screen of the concentrator are connected coaxially, and the agitator and the spiral screw are driven in common. It is characterized by being rotationally driven by a source.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the separation liquid discharge pipe has a double pipe structure of an outer pipe and an inner pipe, and a height of an upper end edge of the inner pipe. The height is set lower than the liquid level in the filter cylinder, and the upper end edge of the inner tube is used as an overflow portion so that the separated liquid overflows from the outer tube to the inner tube or from the inner tube to the outer tube. And

  According to the first aspect of the present invention, since the concentrator is directly connected and disposed on the sludge agglomeration tank, the sludge concentrator can be made compact and its installation space can be kept small. In addition, piping that connects the sludge flocculation tank and the concentrator becomes unnecessary, and flocified sludge that has been flocked in the sludge flocculation tank is directly introduced into the concentrator for concentration treatment. There are no problems such as destruction or blockage of piping.

  According to invention of Claim 2, the sludge concentrated with the concentrator can be discharged | emitted variably from the upper part of a filter cylinder with a screw conveyor.

  According to the invention described in claim 3, since the agitator of the sludge agglomeration tank and the spiral screen of the concentrator are connected coaxially, and these agitator and spiral screw are driven to rotate by a common drive source, The number of points can be reduced to simplify the structure.

  According to the invention described in claim 4, the separation liquid flowing from the outer cylinder to the separation liquid discharge pipe overflows at the upper edge of the inner pipe and flows into the inner pipe or the outer pipe. The overflow portion becomes the circumferential length of the inner pipe, and the length becomes longer than the width (overflow width) of the overflow portion of the conventional sludge concentrating device. Therefore, according to the sludge concentrating apparatus according to the present invention, even if the amount of the separation liquid changes, the fluctuation of the liquid level of the separation liquid in the separation liquid discharge pipe can be suppressed, and the liquid level of the filter cylinder and the separation discharge pipe The fluctuation of the filtration pressure based on the difference with the liquid level of the separation liquid at can be kept small, and the filtration pressure can be kept substantially constant even if the amount of the separation liquid changes.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view showing a basic configuration of a sludge concentrating apparatus according to the present invention. The sludge concentrating apparatus according to the present invention flocks sludge to which a flocculant such as a polymer is added in a sludge aggregating tank 21. The flocified sludge is concentrated by the concentrator 1, and the concentrator 1 is directly connected to the sludge aggregation tank 21.

  The sludge agglomeration tank 21 is a cylindrical tank-like container having an open upper surface, and a raw mud supply pipe 22 is connected to the lower part thereof. Further, in the sludge agglomeration tank 21, a stirrer 24 is rotatably provided, which has a stirring blade 24b mounted on top and bottom of a rotary shaft 24a vertically arranged on the central axis with a phase shifted by 90 °. ing. A ring-shaped flange 13 is bound to the inner peripheral portion of the upper end opening of the sludge aggregation tank 21.

  Further, the concentrator 1 disposed on the sludge agglomeration tank 21 has a cylindrical filter tube 3 disposed in a vertical direction inside a cylindrical tank-shaped outer tube 2 having a hermetically sealed structure. The spiral screw 4 is rotatably accommodated. The concentrator 1 is configured such that the flange 14 bonded to the lower ends of the outer cylinder 2 and the filtration cylinder 3 is overlapped on the flange 13 of the sludge aggregation tank 21 and tightened with a plurality of bolts (not shown). Directly arranged on the tank 21.

  A peripheral surface of a portion of the filter cylinder 3 facing the outer cylinder 2 constitutes a filter surface 3a made of a punching plate or a wedge wire, and a screw conveyor 5 is provided horizontally on the upper part of the filter cylinder 3. Yes. Here, the screw conveyor 5 is configured such that a screw that is rotationally driven by a motor 7 is accommodated in a cylindrical horizontal housing 5a, and a concentrated sludge discharge pipe 8 is directed downward at the lower part of the housing 5a. Is derived.

  Separately, the separated liquid take-out pipes 9 and 10 are led out horizontally from the upper and lower sides of the outer cylinder 2, and the separated liquid take-out pipes 9 and 10 have a double pipe structure with an inner pipe 11a and an outer pipe 11b. It is connected to the upper and lower sides of the outer pipe 11b of the separation liquid discharge pipe 11 to be constituted. Here, the inner tube 11a of the separation liquid discharge tube 11 is open to the upper part in the outer tube 11b and extends downward through the bottom of the outer tube 11b.

  Furthermore, the spiral screw 4 is configured by spirally winding screw blades 4b around a rotating shaft 4a. The rotating shaft 4a and the rotating shaft 24a of the stirrer 24 provided in the sludge aggregation tank 21 are defined as follows. The rotary shafts 4 a and 24 a are arranged coaxially and are directly connected by a coupling 15. A motor 12 as a common drive source is directly connected to the upper end of the rotating shaft 4 a of the spiral screw 4. The outer diameter of the spiral screw 4 is set slightly smaller than the inner diameter of the filtration surface 3a of the filter cylinder 3, and a small gap is formed between the outer peripheral edge of the spiral screw 4 and the filtration surface 3a of the filter cylinder 3. Is formed.

  Thus, sludge (raw mud) is supplied from the raw mud supply pipe 22 to the sludge agglomeration tank 21, and a flocculant such as a polymer is added to the sludge flowing through the raw mud supply pipe 22, and the flocculant is added. The sludge thus produced is agitated by the agitator 24 in the sludge agglomeration tank 21, and the sludge is flocked by aggregating solid components contained therein. The rotating shaft 4a of the spiral screw 4 and the rotating shaft 24a of the stirrer 24 are arranged coaxially, and both are directly connected by the coupling 15, and the common motor 12 is directly connected to the upper end of the rotating shaft 4a. Therefore, the spiral screw 4 and the stirrer 24 are simultaneously driven to rotate at the same speed in the same direction by the common motor 12.

  The flocs sludge flocked in the sludge aggregation tank 21 as described above is introduced into the filter cylinder 3 from below by the spiral screw 4 rotating in the filter cylinder 3 of the concentrator 1 installed on the sludge aggregation tank 21. Is done.

Here, the height of the upper end edge of the inner pipe 11a of the separation liquid discharge pipe 11 is set lower than the sludge liquid level h ₁ in the filter cylinder 3, and the separation liquid is taken out from the outer cylinder 2 as will be described later. The separation liquid discharged to the separation liquid discharge pipe 11 through the pipes 9 and 10 overflows with the upper end edge of the inner pipe 11a of the separation liquid discharge pipe 11 as an overflow portion, and flows from the outer pipe 11b to the inner pipe 11a. Flows in. Accordingly, the liquid level h ₂ of the separation liquid in the separation liquid discharge pipe 11 is lower than the liquid level h ₁ of the sludge in the filter cylinder 3 (h ₂ <h ₁ ), and the difference between both h ₁ and h ₂ (head) Difference) Using the differential pressure based on Δh ₁₂ (= h ₁ −h ₂ ) as the filtration pressure, the water separated from the coagulated sludge passes through the filtration surface 3a of the filtration cylinder 3 and is stored in the outer cylinder 2 as a separation liquid. The

  The separation liquid stored in the outer cylinder 2 flows into the outer pipe 11b of the separation liquid discharge pipe 11 through the separation liquid take-out pipes 9 and 10 connected to the upper and lower sides of the outer cylinder 2, and It flows upward between the tubes 11a, overflows at the upper edge of the inner tube 11a, flows into the inner tube 11a, flows downward in the inner tube 11a, and is discharged to the outside.

  On the other hand, the agglomerated sludge conveyed upward in the filter cylinder 3 by the rotation of the spiral screw 4 is concentrated by separating water in the middle thereof to become concentrated sludge, and this concentrated sludge is filtered by the screw conveyor 5. It is discharged from the upper part of the cylinder 3 in a variable and quantitative manner, and is supplied from a concentrated sludge discharge pipe 8 to a dehydrator (not shown) for dehydration.

  In the above, according to the sludge concentrating apparatus according to the present invention, the concentrator 1 is directly connected to the sludge agglomeration tank 21, so that the sludge concentrating apparatus can be made compact and its installation space can be kept small.

  In addition, the pipe for connecting the sludge agglomeration tank 21 and the concentrator 1 becomes unnecessary, and the agglomerated sludge flocated in the sludge agglomeration tank 21 is directly introduced into the concentrator 1 for concentration treatment. There will be no troubles such as breakage in the middle of the pipe or blockage of the pipe.

  Furthermore, since the agitator 24 of the sludge agglomeration tank 21 and the spiral screen 4 of the concentrator 1 are connected coaxially, the agitator 24 and the spiral screw 4 are rotationally driven by a common drive source. The structure can be simplified by simplifying the structure.

  The separation liquid flowing from the outer cylinder 2 into the separation liquid discharge pipe 11 overflows at the upper edge of the inner pipe 11a of the separation liquid discharge pipe 11 and flows into the inner pipe 11a. The edge becomes an overflow portion, and the length of the overflow portion becomes the circumferential length of the inner pipe 11a, and the length becomes longer than the width (overflow width) of the overflow portion of the conventional sludge concentrating device. .

Therefore, according to the sludge concentrating apparatus of the present invention, even when the separated liquid volume is changed it can be suppressed to be small variations in the water level of separated liquid in the separated liquid discharge pipe 11, the liquid level h ₁ of the filtration tube 3 The fluctuation of the filtration pressure based on the difference Δh ₁₂ (= h ₁ −h ₂ ) with respect to the liquid level h ₂ of the separation liquid in the separation discharge pipe 11 can be kept small, and the filtration pressure can be reduced even if the amount of the separation liquid changes. It can be kept substantially constant. As a result, it is possible to prevent occurrence of leakage of solid components on the filtration surface 3a of the filtration cylinder 3 and clogging of the filtration surface 3a.

  In this embodiment, the separation liquid discharge pipe 11 employs a configuration in which the separation liquid overflows from the outer pipe 11b to the inner pipe 11a, but conversely, the separation liquid overflows from the inner pipe 11a to the outer pipe 11b. A configuration may be adopted.

It is a schematic sectional drawing which shows the basic composition of the sludge concentration apparatus which concerns on this invention. It is the schematic which shows the basic composition of the conventional sludge concentration apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concentrator 2 Outer cylinder 3 Filter cylinder 3a Filtration surface 4 Spiral screw 4a Rotating shaft 4b Screw blade 5 Screw conveyor 5a Housing 5b Screw 6 Concentrated sludge introduction pipe 7 Motor 8 Concentrated sludge discharge pipe 9, 10 Separation liquid discharge pipe 11 Separation liquid Discharge pipe 11a Inner pipe 11b Outer pipe 12 Motor (drive source)
13, 14 Flange 15 Coupling 21 Sludge coagulation tank 22 Raw mud supply pipe 23 Motor 24 Stirrer 24a Rotating shaft 24b Stirring blade h ₁ Liquid level of sludge in the filter tube h ₂ Liquid level of separated liquid in the separated liquid discharge pipe

Claims (4)

A sludge agglomeration tank in which the sludge to which the flocculant is added is agitated with a stirrer to flocate,
A filtration cylinder is accommodated in the outer cylinder, a spiral screw is rotatably accommodated in the filtration cylinder, and the spiral screw is rotationally driven to be introduced into the lower part of the filtration cylinder from the sludge aggregation tank. While conveying the sludge upward, the water contained in the sludge passes through the filtration surface of the filter cylinder and is discharged as a separation liquid from the separation liquid discharge pipe to concentrate the sludge, and the concentrated sludge is filtered. A concentrator that discharges from the top of the tube;
In the sludge concentrator equipped with
A sludge concentrating apparatus, wherein the concentrator is directly connected to the sludge aggregation tank.   The sludge concentration apparatus according to claim 1, wherein the sludge concentrated by the concentrator is discharged from an upper portion of the filter cylinder by a screw conveyor.   The sludge according to claim 1 or 2, wherein the agitator of the sludge agglomeration tank and the spiral screen of the concentrator are coaxially connected, and the agitator and the spiral screw are rotationally driven by a common drive source. Concentrator.   The separation liquid discharge pipe has a double pipe structure of an outer pipe and an inner pipe, the height of the upper end edge of the inner pipe is set lower than the liquid level in the filter cylinder, and the upper end edge of the inner pipe is The sludge concentrating device according to any one of claims 1 to 3, wherein the separating liquid overflows from the outer tube to the inner tube or from the inner tube to the outer tube.

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