JP2003200200A - Sludge filtration concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently thicken sludge by preventing the clogging of a filtration drum, to downsize a sludge filtration concentrator, and to facilitate the maintenance and inspection of the concentrator. <P>SOLUTION: In the filtration concentrator where the closed-end filtration drum 4 equipped with a cylindrical filtration filter 6, a filtrate discharge pipe 8, and a scraper 9 is vertically installed in a sludge storage tank 1, the aperture of the outer surface layer of the filtration filter 6 is most closely formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge filter / concentrator, and more particularly to sludge generated in a water treatment process of a sewer or a sewer, or a pollutant contained in industrial wastewater or general wastewater (hereinafter, sludge). Also, the present invention relates to a sludge filtration concentrating device capable of efficiently concentrating pollutants as a general term.

[0002]

2. Description of the Related Art Heretofore, the following sludge filtration concentrating device for concentrating slurry sludge generated in the water treatment process of waterworks and sewers has been known.

In Japanese Patent Laid-Open No. 63-296810, a slurry guide plate is provided toward the surface of a cylindrical filter drum, and the clearance between the filter drum and the slurry guide plate is set to 1.
A sludge filtration concentrating device having a thickness within the range of 10 mm is disclosed. Hereinafter, this sludge filtration concentrating device will be referred to as Prior Art 1.

Japanese Unexamined Patent Publication (Kokai) No. 55-147114 discloses a sludge filtration concentrating device in which a cylindrical rotary screen is rotatably immersed in a suspension in a storage tank.
Hereinafter, this sludge filtration concentrating device is referred to as Prior Art 2.

Japanese Unexamined Patent Publication (Kokai) No. 9-150200 discloses a sludge filtering and concentrating device in which a cleaning nozzle is attached in a screen drum and a sludge water level is detected to perform water spray cleaning. Hereinafter, this sludge filtration concentrating device is referred to as Prior Art 3.

[0006] Japanese Unexamined Patent Publication No. 2000-202496 discloses a sludge filter concentrating device which scrapes off a sludge cake attached to a filtration drum vertically and rotatably provided in a sludge storage tank by a fixed scraper. Hereinafter, this sludge filtration concentrating device is referred to as Prior Art 4.

[0007] Japanese Unexamined Patent Publication No. 2000-202497 discloses a sludge filter concentrating device that scrapes off a sludge cake attached to a filter drum vertically provided in a sludge storage tank with a rotary scraper. Hereinafter, this sludge filtration concentrating device is referred to as Prior Art 5.

[0008]

However, the above-mentioned prior art has the following problems.

In the prior art 1, since the clearance between the filtration drum and the slurry guide plate is 1 mm or more, the filtration drum is significantly clogged.

The prior art 2 prevents the clogging of the filter medium due to the rotation of the rotary screen, but in reality, the clogging of the filter medium cannot be prevented without a scraper or a cleaning device.

In the prior art 3, washing with water spray is performed from the inside of the screen drum, but it is necessary to use high pressure and a large amount of water to prevent clogging, and only washing with water spray is required. Then, clogging cannot be completely prevented.

[0012] In the prior arts 4 and 5, the sludge cake adhering to the filtration drum is scraped off by a scraper, so the sludge condensing performance is better than that of the other prior arts described above, but the characteristics of the sludge are long-term continuous operation. May cause clogging in the screen.

Further, a sludge concentrating device of a type that pressurizes the raw sludge when filtering and concentrating the sludge has been proposed.
Since the device has a closed structure, it is difficult to perform maintenance and inspection of the device when the filter surface is clogged.

As described above, none of the above-mentioned prior arts can efficiently filter and concentrate sludge due to clogging of the filter drum, and there is a problem in maintenance and inspection of the device. It was

Therefore, the object of the present invention is that clogging of the filtration drum is unlikely to occur, so that sludge can be efficiently concentrated, the size of the device can be reduced, and maintenance and inspection of the device can be easily performed. The present invention provides a sludge filtration concentrating device.

[0016]

The invention according to claim 1 is
In a filtration and concentration device in which a bottomed filtration drum equipped with a cylindrical filtration filter, a filtrate discharge pipe, and a scraper is vertically installed in a sludge storage tank, the outermost surface layer of the filtration filter has the most dense openings. It is characterized in that

The invention according to claim 2 is characterized in that the openings in the inner surface layer portion of the filtration filter are formed most coarsely.

The invention according to claim 3 is characterized in that the openings of the filtration filter are coarsely formed stepwise or continuously from the outer surface layer portion toward the inner surface layer portion.

The invention according to claim 4 is characterized in that the filtration filter is attached to a support member, and the filtration filter and the support member are integrally formed.

According to a fifth aspect of the present invention, the filtrate discharge pipe is connected to a vertical rotary shaft provided in the central axis portion of the filtration drum, and a large number of filtrate discharge holes are formed in the vertical rotary shaft. It is characterized by being present.

The invention according to claim 6 is characterized in that the filtration filter comprises a base material and a felt filter cloth attached to the base material.

The invention according to claim 7 is characterized in that the base material is composed of a monofilament thread or a multifilament thread.

According to the eighth aspect of the invention, at least one of the inner surface and the outer surface of the filtration drum is provided with a cleaning means for removing the sludge cake adhering to the filtration drum by spraying a fluid. It has characteristics.

The invention according to claim 9 is characterized in that the distance between the scraper and the filtration filter is less than 1 mm.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the sludge filtration concentrating device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing a sludge concentrating treatment apparatus of the present invention.

In FIG. 1, reference numeral 1 denotes a sludge storage tank having a funnel-shaped bottom, an original sludge supply pipe 2 is connected to the upper part, and a concentrated sludge discharge pipe 3 is connected to the bottom. For the supply of the slurry-like raw sludge 11 from the raw sludge supply pipe 2 and the discharge of the concentrated sludge from the concentrated sludge discharge pipe 3, use a pump, a flow meter, a densitometer, etc. to properly adjust the sludge flow rate and sludge concentration. It is done under control. Since the bottom part of the sludge storage tank 1 is formed in a funnel shape, the concentrated sludge is effectively discharged from the concentrated sludge discharge pipe 3. If sludge scraping means is provided at the bottom of the sludge storage tank 1, the sludge can be discharged more effectively.

The sludge storage tank 1 is, for example, a filtration / concentration facility such as a sedimentation tank, a drainage pond, and a concentration tank in an existing water treatment plant, a first sedimentation tank, a final sedimentation tank, and a sludge concentration equipment in an existing sewage treatment plant. It is also possible to directly use the filtration and concentration equipment such as.

Reference numeral 4 is a cylindrical bottomed filtration drum provided vertically in the sludge storage tank 1. The filtration drum 4 comprises a cylindrical lattice-shaped support member 5 around which a filtration filter 6 is attached, and the filtration drum 4 is suspended in the sludge storage tank 1 through a vertical rotary shaft 7 formed with a number of filtrate discharge holes 7A, It is supported. In this way, the filtration drum 4 is attached to the vertical rotation shaft 7
By suspending the sludge in the sludge storage tank 1 via the filter, it is not necessary to provide a support mechanism for the filtration drum 4 in the sludge storage tank 1. Therefore, the structure of the device is simplified, and moreover,
By pulling up the vertical rotary wheel 7, the filter drum 4
Since the sludge can be taken out from the sludge storage tank 1, maintenance and inspection of the device can be easily performed.

A filtrate discharge pipe 8 is connected to a vertical rotary shaft 7 protruding from the bottom of the filtration drum 4. The filtrate discharge pipe 8 is connected to the filtration drum 4 so as to rotate in a watertight manner and freely. The sludge is filtered by the filtration filter 6 due to the head difference between the water level of the sludge stored in the sludge storage tank 1 and the filtrate in the filtration drum 4, and the filtrate 12 is
The filtrate flows into the filtration drum 4, and the filtrate discharge hole 7 of the vertical rotary shaft 7
It is discharged to the outside of the sludge storage tank 1 through A or the filtrate discharge pipe 8. If the sludge storage tank 1 is large, a plurality of filtration drums 4 may be provided.

If a wedge screen or a filter cloth is used as the filter 6, the sludge filtering ability and the sludge cake peeling property are improved. By using a filter cloth composed of a base material and a felt filter cloth woven therein, the sludge concentration effect can be further improved, and the base material may be a monofilament thread or a multifilament thread. By using it, it is possible to more effectively prevent clogging in the filtration filter. In particular, the use of monofilament yarn can prevent clogging more effectively. FIG. 2 shows a filtration filter 6 including a felt filter cloth 14 woven into a base material 13.
Is shown in the schematic diagram. The openings in the outer surface layer portion of the felt filter cloth 14 shown in FIG. 2 are formed more densely than the inside of the felt filter cloth 14 by heat treatment.

The opening of the filter 6 is the original sludge 11
The outer surface layer portion in contact with is most densely formed, and the openings in the filtration filter 6 are formed coarser than the outer surface layer portion of the filtration filter 6. Therefore, the fine sludge and the like that have passed through the surface of the filtration filter 6 pass through the filtration filter 6 without being clogged inside the filtration filter 6, so that clogging of the filtration filter 6 can be effectively prevented. By forming the openings in the inner surface layer of the filtration filter 6 to be the most coarse, the effect of preventing clogging inside the filtration filter 6 can be further improved. Figure 3
FIG. 2 is a schematic cross-sectional view of a filtration filter 6 in which the mesh size of the outer surface layer portion is made denser than the mesh size of the inner surface layer portion and the roughness of the mesh size changes in two stages.

Further, the effect of preventing clogging inside the filtration filter 6 is further improved by forming the openings of the filtration filter 6 from the outer surface layer portion toward the inner surface layer portion in a continuous or stepwise manner. be able to.

The filter 6 and the supporting member 5 are also provided.
By integrally molding and, the structure of the filtration drum 4 is simplified, and the handleability is also improved.

Reference numeral 9 is a scraper provided in the sludge storage tank 1 for scraping off the sludge cake attached to the filtration drum 4. The scraper 9 is preferably made of ultra high molecular weight polyethylene. The scraper 9 may have a linear shape as shown in the drawing, but may have a spiral shape so as to surround the periphery of the filtration drum 4. When the scraper 9 is formed in a spiral shape, the scraped sludge cake can be automatically pushed out downward, so that the scraped sludge cake can be prevented from adhering to the scraper 9 again. The spacing between the scraper 9 and the filtration drum 4 is 1 mm
When it is set to less than 1, the clogging of the filtration filter 5 due to the sludge cake adhering to the filtration drum 4 can be reliably prevented.

In this example, the filtration drum 6 is rotated and the filtration filter 6 is fixed by the fixed scraper 9.
Although the sludge cake adhering to the filter is scraped off, the filter drum 4 may be fixed and the scraper 9 may be rotated along the circumference of the filter drum 4, or the filter drum 4 and the scraper 9 may be rotated in opposite directions. It may be configured to be rotated in the direction to scrape off the sludge attached to the filtration drum 4.

Reference numeral 10 is a cleaning means for further improving the scraping effect of the sludge cake by the scraper 9, and a fluid such as air or water is directed toward at least one of the inner surface and the outer surface of the filtration drum 4. By spraying, the separability of the sludge cake attached to the filtration drum 4 is improved. In this example, the fluid is sprayed on the outer surface of the filtration drum 4.

According to the sludge filtering and concentrating apparatus of the present invention having the above-mentioned structure, the raw sludge is concentrated in the following manner.

The raw sludge 11 in the form of slurry is the raw sludge supply pipe 2
Is supplied into the sludge storage tank 1 and is filtered by the rotating filtration drum 4. The filtrate 12 that has flowed into the filtration drum 4 flows into the vertical rotation shaft 7 through the filtrate discharge hole 7A of the vertical rotation shaft 7 and is discharged from the sludge storage tank 1 through the filtrate discharge pipe 8.

On the other hand, the sludge cake adhering to the filtration drum 4 is scraped off by the scraper 9, and the sludge storage tank 1
Settles to the bottom of the. The concentrated sludge settled on the bottom of the sludge storage tank 1 in this manner is discharged to the outside of the sludge storage tank 1 by the pump P (or the internal pressure) of the sludge storage tank 1.

When the sludge cake is scraped off from the filter drum 4 by the scraper 9, if a fluid such as air or water is blown toward the filter drum 4 by the cleaning means 10, the sludge cake is easily separated from the filter drum 4. . Therefore, the scraping effect of the sludge cake by the scraper 9 can be more reliably performed.

[0042]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto.

Sludge having an SS concentration of 1.4% generated in a water purification plant was continuously filtered and concentrated to an SS concentration of 5% by the above sludge filtration concentrating device. Figure 4 shows the particle size distribution of the sample sludge. From Fig. 4, the particle size distribution of the sample sludge is 0.2-80μ.
m, it has a peak in 4-5 micrometers. This sludge
Filtering concentration was carried out for 24 hours using the conventional filters 1 to 12 and the filters 1 to 6 of the present invention shown in Table 1, and the filtration rate and the filtrate SS concentration at the time of 12 hours and 24 hours of operation were examined. The results are shown in Table 2. In Table 2, the pore size of the filtrate surface is the pore size of the inner surface layer of the filtration drum, and the pore size of the mounting surface is the pore size of the outer surface layer of the filtration drum.

[0044]

[Table 1]

[0045]

[Table 2]

As is clear from Table 2, when the conventional filters 1 to 12 were used, the filtration rate was remarkably decreased and the filtrate SS concentration was very high. When any of 1 to 6 was used, no decrease in filtration rate was observed, and the filtrate SS concentration showed a very low value.

From the above, it can be seen that the filter of the prior art causes clogging, but the filter of the present invention does not cause clogging.

[0048]

As described above, according to the present invention, the following useful effects are brought about. It is possible to effectively prevent clogging of the filtration filter by forming the outermost surface layer portion of the filtration filter with the closest openings. Since the entire filtration drum is filtered, there is no waste, and since the sludge cake that adheres to the filtration drum is always removed by the scraper, clogging is less likely to occur. Therefore, long-term operation is possible and high filtration efficiency is obtained. Since the filtration drum is suspended and supported in the sludge storage tank via the vertical rotation shaft, it is not necessary to provide a support mechanism for the filtration drum in the sludge storage tank. Therefore, the structure of the device is simplified, and since the filtration drum can be taken out from the sludge storage tank by pulling up the vertical rotation shaft, the device can be downsized and the maintenance and inspection of the device can be facilitated. You can do it. By using a felt filter cloth as the filter and using monofilament yarn or multifilament yarn as the base material of the filter, it is possible to prevent clogging of the filter more effectively.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a sludge filtration concentrating device of the present invention.

FIG. 2 is a schematic cross-sectional view showing a filtration filter made of a felt filter cloth woven into a base material.

FIG. 3 is a schematic cross-sectional view showing a filtration filter in which the mesh size of the outer surface layer portion is made denser than the mesh size of the inner surface layer portion and the roughness of the mesh size changes in two stages.

FIG. 4 is a graph showing a particle size distribution of sample sludge.

[Explanation of symbols]

1: Sludge storage tank 2: Raw sludge supply pipe 3: Concentrated sludge discharge pipe 4: Filter drum 5: Support member 6: Filtration filter 7: Vertical rotation axis 7A: Filtrate discharge hole 8: Filtrate discharge pipe 9: scraper 10: Cleaning means 11: Raw sludge 12: Filtrate 13: Base material 14: felt filter cloth

Continued front page    (72) Inventor Shohei Fukada             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Kenichiro Mizuno             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Shunichi Kamezaki             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F-term (reference) 4D019 AA03 BA12 BB05 BB10 BD02                       CA03 CB04 DA08                 4D026 BA03 BB01 BC23 BC26 BC29                       BD02 BD06 BF05 BF11                 4D059 AA03 BE11 BE13

Claims (9)

[Claims] 1. A filtration concentrator in which a bottomed filtration drum equipped with a cylindrical filtration filter, a filtrate discharge pipe and a scraper is vertically installed in a sludge storage tank, wherein an outer surface layer portion of the filtration filter is opened. The sludge filtration concentrator is characterized by being formed most densely. 2. The sludge filtration concentrator according to claim 1, wherein the inner surface layer of the filtration filter has the most coarse openings. 3. The sludge filtration concentrating device according to claim 1, wherein the openings of the filtration filter are coarsely formed stepwise or continuously from the outer surface layer portion toward the inner surface layer portion. . 4. The filter according to claim 1, wherein the filter is attached to a support member, and the filter and the support member are integrally formed. The sludge filtration concentrating device described in 1. 5. The filtrate discharge pipe is connected to a vertical rotation shaft provided in a central axis portion of the filtration drum, and a large number of filtrate discharge holes are formed in the vertical rotation shaft. The sludge filtration concentrating device according to any one of claims 1 to 4. 6. The sludge filter concentrate according to claim 1, wherein the filter comprises a base material and a felt filter cloth attached to the base material. apparatus. 7. The sludge filtering and concentrating device according to claim 6, wherein the base material is made of a monofilament thread or a multifilament thread. 8. The cleaning means for removing the sludge cake adhering to the filtration drum by spraying a fluid is provided on at least one of the inner surface and the outer surface of the filtration drum. The sludge filtration concentrating device according to any one of 1 to 7. 9. The sludge filtration concentrating device according to claim 1, wherein a distance between the scraper and the filtration filter is less than 1 mm.