JP2003220400A - Sludge concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge concentrator capable of being reduced in equipment size and cost in that the efficient concentration of sludge, and the inhibition of screen clogging can be achieved by suitably scraping the adherent sludge cake along the direction of the depth of a vertical filter drum to keep the filtration rate high. <P>SOLUTION: The sludge concentrator is one constituted by vertically forming a bottomed filter drum 4 provided with a cylindrical filter screen, a filtrate discharge pipe, and a plurality of scrapers 8, wherein the number of scrapers 8 is larger at the lower peripheral part than at the upper peripheral part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sludge concentrating device,
In particular, wastewater or sludge generated in water treatment processes such as water supply, sewerage or human waste treatment, and industrial wastewater and general wastewater containing pollutants can be efficiently separated, and further, the device can be downsized and the cost can be reduced. The present invention relates to a sludge concentrating device that can be made into a product.

[0002]

2. Description of the Related Art Conventionally, as a sludge concentrating device for slurry sludge generated in the water treatment process of waterworks and sewers, a device provided with a cylindrical filtration drum in a sludge storage tank is disclosed in the following publication.

The devices disclosed in Japanese Patent Application Laid-Open Nos. 12-202496 and 12-202497 are provided with a vertical cylindrical filtration drum having a scraper in a sludge storage tank. Hereinafter, this is referred to as a conventional sludge concentrator.

[0004]

However, the above-mentioned conventional sludge concentrating device has the following problems.

[0005] A structure is employed in which the sludge cake adhering to the screen of the cylindrical filtration drum is uniformly scraped in the depth direction by a continuous scraping operation by a scraper to prevent a decrease in the filtration speed. The amount of sludge cake adhering to the filtration drum increases in the deeper part where the head difference increases, and the filtration amount decreases. In addition, since the sludge concentration increases as the depth increases due to the natural sedimentation of the sludge, the amount of sludge cake that adheres also increases at the deeper part, and the filtration amount decreases. Since a larger amount of sludge adheres to the deeper part, there is also a problem that clogging becomes faster at the deeper part of the screen.

As described above, the above-mentioned conventional sludge concentrator has a problem that sludge cannot be concentrated efficiently.

Accordingly, an object of the present invention is to appropriately scrape off the amount of the attached sludge cake in the depth direction of the vertical filtration drum by using a scraper, thereby keeping the filtration rate high and efficiently concentrating the sludge. You can, and
The present invention relates to a sludge concentrating device that can reduce the size of the device and can reduce the cost because clogging of the screen can be suppressed.

[0008]

The invention according to claim 1 is
In a sludge concentrating device in which a bottomed filtration drum including a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank, the scraper is a top part of the filtration screen. This is characterized in that the lower circumferential direction is installed more than the lower direction.

According to a second aspect of the present invention, there is provided a sludge concentrating device in which a bottomed filtration drum including a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank. The clearance between the scraper below the filter screen and the filter screen is smaller than the clearance between the scraper above the filter screen and the filter screen.

According to a third aspect of the present invention, there is provided a sludge concentrating device in which a bottomed filtration drum including a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank. The scraper is installed more in the lower circumferential direction than in the upper circumferential direction of the filtration screen, and the clearance between the scraper and the filtration screen under the filtration screen is:
It is characterized in that it is smaller than the clearance between the scraper and the filter screen above the filter screen.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the sludge 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 device of the present invention, FIG. 2 is a schematic perspective view showing a filtering drum in which the number of scrapers in the depth direction is changed, and FIG. 3 is a plan view of the filtering drum. And (A) is a sectional view taken along line AA of FIG.
2B is a sectional view taken along line BB of FIG. 2, and FIG.
4 is a sectional view taken along line C, FIG. 4D is a sectional view taken along line DD of FIG.
5 is a schematic perspective view showing a filtration drum in which the clearance of the scraper in the depth direction is changed, FIG. 5 is a plan view of the filtration drum in FIG. 4, and FIG. 6 is a filtration in which the number of scrapers in the depth direction and the clearance are changed. It is a schematic perspective view which shows a drum.

1 to 6, reference numeral 1 denotes a sludge storage tank having a funnel-shaped bottom, a raw sludge supply pipe 2 is connected to the upper part, and a concentrated sludge discharge pipe 3 is connected to the bottom. . For supplying the slurry-like raw sludge from the raw sludge supply pipe 2 and discharging the concentrated sludge from the concentrated sludge discharge pipe 3, use the pump P, a flow meter, a densitometer, etc. to properly adjust the flow rate of the sludge and the 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. Sludge storage tank 1
If sludge collecting means is provided at the bottom of the sludge, the sludge can be discharged more effectively.

The sludge storage tank 1 is, for example, a filtration / concentration equipment such as a sedimentation tank, a sludge 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 denotes a cylindrical bottomed filtration drum which is vertically fixed in the sludge storage tank 1. The filtration drum 4 is composed of a cylindrical cage frame 5 and a filtration screen 6 attached to the periphery thereof, and is fixed to a filtrate discharge pipe 7 having a large number of filtrate discharge holes 7A formed therein. The filtrate discharge pipe 7 is pierced from the central axis portion of the filtration drum 4 through the bottom 4A of the filtration drum 4 to the outside of the sludge storage tank 1.

The sludge is filtered by the screen 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, the filtrate flows into the filtration drum 4, and the filtrate discharge pipe 7 From the filtrate discharge hole 7A of the filtrate discharge pipe 7
It is discharged through the sludge storage tank 1. If a wedge screen or a filter cloth is used as the material of the screen 6, the sludge filtering ability and the sludge cake peeling property are improved. If the sludge storage tank 1 is large, a plurality of filtration drums 4 may be provided.

Reference numeral 8 is a scraper for scraping off the sludge cake adhering to the filtration drum 4, which is rotatable around the filtrate discharge pipe 7 in the sludge storage tank 1 and scrapes off the sludge cake. The material of the scraper 8 is preferably ultra-high molecular weight polyethylene. Scraper 8
May have a linear shape as shown, but may have a spiral shape so as to surround the periphery of the filtration drum 4. When the scraper 8 is formed in a spiral shape, the scraped sludge can be pushed downward, so that the scraped sludge can be prevented from adhering to the scraper 8 again.

The sludge cake adhering to the filtration drum 4 becomes thicker as the depth becomes deeper and the filtration pressure becomes higher, and as the depth becomes deeper and the sludge concentration around the filtration drum 4 becomes higher due to the sedimentation phenomenon. As a result, the filtration rate is reduced.

Therefore, by increasing the number of scrapers 8 installed in the deeper portion or decreasing the clearance for scraping sludge by the scrapers 8, the thickness of the sludge cake to be deposited can be reduced and the filtration speed can be increased. It becomes possible. Furthermore, since the thickness of the sludge cake that adheres to the deep part becomes thin, the progress of clogging is suppressed even if a long-term filtration operation is performed,
It is possible to obtain a stable filtration rate.

2 and 3 show the case where the number of scrapers 8 installed is increased in the deeper part. That is, the number of scrapers 8 to be installed from the upper part to the lower part of the filtration drum 4 is successively increased to 1, 2, 3, and 4. In this case, the scrapers at one location may be integrated vertically.

FIG. 4 shows a case where the clearance between the scraper 8 and the screen 6 is made smaller at a deeper portion.
That is, four scrapers 8 are provided around the filtration drum 4 from the upper part to the lower part, and the clearances of the scraper 8 are sequentially set to 1 mm, 0.
It is as small as 5 mm, 0.25 mm, and 0 mm.

In FIG. 5, the number of scrapers 8 to be installed is increased in the deeper part, and the scrapers 8 and the screen 6 are arranged.
Shows the case when the clearance between and is reduced. That is,
The scraper 8 extends from the upper part to the lower part of the filtration drum 4.
The number of installed sheets is sequentially increased to 1, 2, 3, and 4, and the clearance of the scraper 8 is sequentially reduced from the top to the bottom by 1 mm, 0.5 mm, 0.25 mm, and 0 mm. . The increased number of scrapers 8 and the size of the clearance are not limited to this.

In the above example, the filter drum 4 is fixed and the scraper 8 rotates around it. However, it goes without saying that the present invention can be applied to the case where the filter drum 4 is rotated. In this case, the scraper 8 is fixed.

[0024]

As described above, according to the present invention, the number of scrapers for scraping off the sludge cake that adheres is increased in the depth direction, or the clearance with the screen is adjusted to increase the filtration drum. The sludge cake adhering to the can be efficiently removed, the filtration rate can be maintained high, and high filtration efficiency can be obtained.
Further, since the amount of sludge cake that adheres is reduced, clogging of the screen is less likely to occur, and long-term operation is possible and high filtration efficiency is obtained. Therefore, useful effects such as downsizing of the device and cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a sludge concentration treatment device of the present invention.

FIG. 2 is a schematic perspective view showing a filtration drum in which the number of scrapers in the depth direction is changed.

3A and 3B are plan views of the filtration drum, in which FIG. 3A is a sectional view taken along the line AA of FIG. 2, and FIG. 3B is a sectional view taken along the line BB of FIG.
2C is a sectional view taken along the line CC of FIG. 2, and FIG.
It is a -D line sectional view.

FIG. 4 is a schematic perspective view showing a filtration drum in which the clearance of the scraper in the depth direction is changed.

5 is a plan view of the filtration drum of FIG.

FIG. 6 is a schematic perspective view showing a filtration drum in which the number of scrapers and the clearance in the depth direction are changed.

[Explanation of symbols]

1: Sludge storage tank 2: Raw sludge supply pipe 3: Concentrated sludge discharge pipe 4: Filter drum 4A: bottom 5: Frame 6: Screen 7: Filtrate discharge pipe 7A: Filtrate discharge hole 8: scraper

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoru Udagawa             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F term (reference) 4D041 AA16 AB03 AB05 AB15 AC03                       AD16 CA04 CB07                 4D059 AA03 BE04 BE11 BE13 BE34                       BE35 BE51 CB18

Claims (3)

[Claims] 1. A sludge concentrating device in which a bottomed filtration drum comprising a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank, wherein the scraper comprises: The sludge concentrator is characterized in that the filter screen is installed more in the lower circumferential direction than in the upper circumferential direction. 2. A sludge concentrating device in which a bottomed filtration drum having a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank, The sludge concentrating device, wherein the clearance between the scraper and the filtration screen is smaller than the clearance between the scraper and the filtration screen above the filtration screen. 3. A sludge concentrating device in which a bottomed filtration drum comprising a cylindrical filtration screen, a filtrate discharge pipe, and a plurality of scrapers is vertically provided in a sludge storage tank, wherein the scraper is The lower circumferential direction is installed more than the upper circumferential direction of the filtration screen,
A sludge concentrating device, wherein a clearance between the scraper below the filter screen and the filter screen is smaller than a clearance between the scraper above the filter screen and the filter screen.