JP6141805B2 - Method and apparatus for concentrating sludge - Google Patents

Description

  The present invention relates to a sludge concentration method and apparatus in a sludge concentration tank having a hopper structure.

  Generally, in the purification process of sewage and wastewater, the treatment tanks are treated in the order of aeration sand tank, raw water pump tank, flow rate adjustment tank, aeration tank, precipitation tank, sprinkling pump tank, disinfection tank. The excess sludge extracted from the sedimentation tank by the sludge extraction pump is guided to the sludge concentration tank, the desorbed liquid treated in the sludge concentration tank is returned to the flow rate adjustment tank, and the precipitated concentrated sludge is sent to the sludge storage tank. It is stored and then removed. Conventionally, in order to improve the efficiency of solid-liquid separation in this sludge concentration tank, a water channel rod is installed vertically in the sludge concentration tank, and this water channel rod is moved laterally to form a water channel in the sludge liquid. There has been proposed a method and an apparatus for concentrating sludge so as to increase the sedimentation rate of particle groups (see, for example, Patent Documents 1 and 2).

JP 2001-321800 A JP 2003-200006 A

  In the sludge concentration method and apparatus described in Patent Documents 1 and 2, the water channel rod is exposed on the water surface and gently rotated in the tank to form a water channel. Further, in the sludge concentration method and apparatus described in Patent Document 2, the fixed wings for waterway rods are provided radially and horizontally on the rotating shaft arranged in the vertical direction at the center of the tank, and the waterway rods are provided on the fixed wings. Is provided in the vertical direction, and the rotating shaft is slowly rotated to form a water channel.

  However, in the above conventional sludge concentration method and apparatus, since the upper end of the water channel rod is extended above the water surface, the length of the water channel rod is increased when the concentration tank is enlarged, and the number of water channel rods to be arranged is increased. There is a problem that the driving device for the waterway rod is enlarged and the cost is increased. In addition, since the number of waterway rods is large, especially in the central part of the concentration tank, the density becomes high, and the residue in the sludge is entangled with the waterway rods, resulting in the formation of waterways and the reduction of the concentration effect. For this reason, there is a problem that work such as entanglement, removal of residue and cleaning must be frequently performed.

  The present invention has been made in order to solve the above-mentioned problems. With a simple configuration, the solid-liquid separation of the liquid to be treated in the concentration tank can be performed reliably and quickly, and the concentration performance and cost of sludge can be improved. An object of the present invention is to provide a method and apparatus for concentrating sludge that can be downed.

A method for concentrating sludge according to claim 1 of the present invention is a hopper-structured sludge concentration tank that constitutes a purification process of sewage or waste water, and the introduced liquid to be treated is solidified into a desorbed liquid and a concentrated sludge. A plurality of rods arranged in the vertical direction are arranged in a sludge concentration tank for liquid separation, and these rods are rotated so that the liquid concentration is low due to negative pressure on the rear side in the traveling direction of the rods in the liquid to be treated. A low-concentration liquid path forming means is provided to form a path, and the upper ends of these rods are cut into short lengths so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle of the sludge concentration tank, a concentrated sludge extraction pipe communicating with the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means rotates with the upper end protruding upward from the concentrated sludge extraction pipe Connected to the drive unit, the lower end is below the concentrated sludge extraction pipe It has a rotating shaft that extends and faces the bottom surface, and the bar is connected to the lower end of the rotating shaft and extends along the inclination of the conical bottom, and is continuous with the connecting portion and upwards. It has a vertical bar portion that rises, and is characterized in that, during the solid-liquid separation process, the bar is rotated to form a path with a low liquid concentration in the liquid to be processed in the vertical direction.

In the sludge concentration method according to claim 1 of the present invention, the sludge concentration tank has a hopper structure that constitutes a purification process of sewage or waste water, and the introduced liquid to be treated is separated into a desorbed liquid and a concentrated sludge. A plurality of rods arranged in the vertical direction are arranged in a sludge concentration tank for liquid separation, and these rods are rotated so that the liquid concentration is low due to negative pressure on the rear side in the traveling direction of the rods in the liquid to be treated. A low-concentration liquid path forming means is provided to form a path, and the upper ends of these rods are cut into short lengths so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle of the sludge concentration tank, a concentrated sludge extraction pipe communicating with the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means rotates with the upper end protruding upward from the concentrated sludge extraction pipe Connected to the drive, the lower end is below the concentrated sludge extraction pipe And a rotating shaft that extends to the bottom surface and has a rod that is connected to the lower end of the rotating shaft and extends along the inclination of the conical bottom, and is continuous with the connecting portion. In the solid-liquid separation process, the rod is rotated to form a path with low liquid concentration in the vertical direction in the liquid to be treated during the solid-liquid separation process. When the bar rotates, a negative pressure part is generated in the processed liquid at the rear side in the direction of travel of the bar, and a liquid component having a lower specific gravity is collected in this negative pressure part than the high-concentration sludge. A path having a low liquid concentration is formed in the processing liquid in the vertical direction. The liquid having a low specific gravity rises and forms a separated liquid-liquid layer on the upper side of the liquid to be treated, so that the detached liquid layer is formed in a short time and the working efficiency is improved.

The sludge concentration apparatus according to claim 2 of the present invention is a sludge concentration tank having a hopper structure that constitutes a part of a purification process of sewage or waste water, wherein the introduced liquid to be treated is a desorbed liquid and concentrated sludge. A plurality of bars arranged in the vertical direction are arranged in a sludge concentrating tank that separates into solid and liquid, and these bars are rotated so that the liquid in the liquid to be treated is moved backward by the negative pressure in the direction of travel. A low-concentration liquid path forming means is provided to form a low-concentration path, and the upper ends of these rods are cut short so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle part of the sludge concentration tank, a concentrated sludge extraction pipe connected to the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means has an upper end upward from the concentrated sludge extraction pipe. Protruding and connected to the rotary drive, the lower end is from the concentrated sludge extraction tube A rotating shaft extending toward the bottom and facing the bottom surface, and a bar member connected to a lower end of the rotating shaft and extending along the inclination of the conical bottom, and continuous with the connecting portion, It is characterized by having a vertical bar portion that rises upward .

The sludge concentration apparatus according to claim 2 of the present invention is a sludge concentration tank having a hopper structure that constitutes a part of a purification process of sewage or wastewater, wherein the introduced liquid to be treated is a desorbed liquid and concentrated sludge. A plurality of bars arranged in the vertical direction are arranged in a sludge concentrating tank that separates into solid and liquid, and these bars are rotated so that the liquid in the liquid to be treated is moved backward by the negative pressure in the direction of travel. A low-concentration liquid path forming means is provided to form a low-concentration path, and the upper ends of these rods are cut short so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle part of the sludge concentration tank, a concentrated sludge extraction pipe connected to the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means has an upper end upward from the concentrated sludge extraction pipe. Protruding and connected to a rotary drive, the lower end is a concentrated sludge extraction tube A rotating shaft extending downward and facing the bottom surface is provided, and the bar is connected to the lower end of the rotating shaft and extends along the inclination of the conical bottom, and is continuous with the connecting portion. By having a vertical bar part that rises upward, when the bar rotates during the solid-liquid separation process, a negative pressure part is generated on the rear side in the traveling direction of the bar in the liquid to be processed. A liquid component having a lighter specific gravity than the high-concentration sludge component gathers in the negative pressure portion, and a path with a low liquid concentration is formed in the liquid to be treated. The liquid with a low specific gravity rises to form a separated liquid-liquid layer on the upper side of the liquid to be treated, so that the detached liquid layer is formed in a short time, which improves the sludge concentration performance. To do. Further, since the dimensions of the bar can be shortened, the cost can be reduced.

The sludge concentration apparatus according to claim 3 of the present invention is characterized in that the upper end of the bar is set to a height approximately half the design water level of the liquid to be treated.

  The sludge concentrating device according to claim 4 of the present invention is configured by connecting the rod members with a reinforcing material, loosely fitting an annular member on the outer periphery of the concentrated sludge extraction pipe, and connecting the annular member and the rod member. It is characterized by having a guide.

A method for concentrating sludge according to claim 1 of the present invention is a hopper-structured sludge concentration tank that constitutes a purification process of sewage or waste water, and the introduced liquid to be treated is solidified into a desorbed liquid and a concentrated sludge. A plurality of rods arranged in the vertical direction are arranged in a sludge concentration tank for liquid separation, and these rods are rotated so that the liquid concentration is low due to negative pressure on the rear side in the traveling direction of the rods in the liquid to be treated. A low-concentration liquid path forming means is provided to form a path, and the upper ends of these rods are cut into short lengths so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle of the sludge concentration tank, a concentrated sludge extraction pipe communicating with the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means rotates with the upper end protruding upward from the concentrated sludge extraction pipe Connected to the drive unit, the lower end is below the concentrated sludge extraction pipe It has a rotating shaft that extends and faces the bottom surface, and the bar is connected to the lower end of the rotating shaft and extends along the inclination of the conical bottom, and is continuous with the connecting portion and upwards. It has a vertical bar part that rises, and at the time of solid-liquid separation processing, the bar is rotated to form a low liquid concentration path in the vertical direction in the liquid to be processed. Solid-liquid separation of the liquid to be treated can be performed reliably and quickly, and the sludge concentration performance can be improved.

The sludge concentration apparatus according to claim 2 of the present invention is a sludge concentration tank having a hopper structure that constitutes a part of a purification process of sewage or waste water, wherein the introduced liquid to be treated is a desorbed liquid and concentrated sludge. A plurality of bars arranged in the vertical direction are arranged in a sludge concentrating tank that separates into solid and liquid, and these bars are rotated so that the liquid in the liquid to be treated is moved backward by the negative pressure in the direction of travel. A low-concentration liquid path forming means is provided to form a low-concentration path, and the upper ends of these rods are cut short so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank. In the middle part of the sludge concentration tank, a concentrated sludge extraction pipe connected to the concentrated sludge extraction pump is arranged, and the low concentration liquid path forming means has an upper end upward from the concentrated sludge extraction pipe. Protruding and connected to the rotary drive, the lower end is from the concentrated sludge extraction tube A rotating shaft extending toward the bottom and facing the bottom surface, and a bar member connected to a lower end of the rotating shaft and extending along the inclination of the conical bottom, and continuous with the connecting portion, Since it has a vertical bar portion that rises upward, solid-liquid separation of the liquid to be treated in the concentration tank can be performed reliably and quickly, and the sludge concentration performance can be improved. Moreover, the dimension of a bar can be shortened and cost reduction can be aimed at.

FIG. 1 is an overall explanatory view showing a concentrating device used in a sludge concentrating method according to an embodiment of the present invention in a sludge concentrating tank constituting a part of a purification treatment process. (Example 1) 2 (A) and 2 (B) are a longitudinal sectional view and an explanatory view as seen from above of the sludge concentrator in FIG. 1, respectively. 3 (A) and 3 (B) are explanatory views showing the behavior of the bar of the sludge concentrator in FIG. 1, respectively.

  A part of the purification process of sewage or waste water, with the purpose of ensuring solid-liquid separation of the liquid to be treated in the concentration tank reliably and promptly, and improving sludge concentration performance and cost reduction. A sludge concentration tank is a sludge concentration tank that solid-liquid separates the liquid to be treated into separated liquid and concentrated sludge, and a plurality of bars arranged in the vertical direction are arranged. A low-concentration liquid passage forming means for forming a low-concentration liquid passage is formed on the rear side in the traveling direction of the bar material in the liquid to be treated by a negative pressure, and the upper end of the bar material is a sludge concentration tank. The sludge extraction pipe connected to the sludge extraction pump is arranged at the center of the sludge concentration tank. The low-concentration liquid path forming means, the upper end protrudes upward from the sludge extraction pipe A rotating shaft connected to the rolling drive device, the lower end of the rotating shaft extending downward from the sludge extraction pipe and facing the bottom surface, and a bar connected to the lower part of the rotating shaft via a connecting portion, This was realized by setting the upper end of the material to approximately half the design water level of the liquid to be treated.

  Hereinafter, the present invention will be described with reference to embodiments shown in the drawings. As shown in FIG. 1, the sludge concentration apparatus 2 according to one embodiment of the present invention is installed in a sludge concentration tank 10 constituting a part of the purification treatment process. In the purification treatment system S based on the purification treatment process of FIG. 1, the treatment tanks are arranged in the order of the aeration sedimentation tank 3, the raw water pump tank 4, the flow rate adjustment tank 5, the aeration tank 6, the precipitation tank 7, the watering pump tank 8, and the disinfection tank 9. The excess sludge Lsl extracted from the sedimentation tank 7 by the sludge extraction pump 12 is guided to the sludge concentration tank 10, and the desorbed liquid Lsp treated in the sludge concentration tank 10 is returned to the flow rate adjusting tank 5 through the desorbed liquid pipe 13. The concentrated sludge Slg that has been precipitated is sent to and stored in the sludge storage tank 11 and then discharged. In this purification treatment system S, sand and residue are removed from the inflowing sewage in the order of the aeration sedimentation tank 3, the raw water pump tank 4, and the flow rate adjustment tank 5, and are biologically treated in the aeration tank 6 to oxidize and decompose pollutants. (Refer process S-1). The liquid to be treated that has been oxidatively decomposed in the aeration tank 6 is separated into treated water and sludge in the sedimentation tank 7 and then led to the disinfection tank 9 through the watering pump tank 8 and discharged after chlorine disinfection ( Step S-2). Then, surplus sludge generated in the course of biological treatment in the aeration tank 6 is sent from the sedimentation tank 7 to the sludge concentration tank 10, and is carried out from the sludge storage tank 11 after being concentrated in the sludge concentration tank 10 (process). S-3). In the present embodiment, domestic wastewater or the like is targeted as the sewage of the liquid to be treated.

  In the sludge concentration tank 10, as shown in FIGS. 2A and 2B, a concentrated sludge extraction pump 14 is provided on a support base 16 attached to the lower side of the upper opening 10B. A concentrated sludge extraction pump 15 is connected to the concentrated sludge extraction pump 14. The concentrated sludge extraction pipe 15 is vertically extended downward from the pump 14, and the lower end 15 </ b> A is disposed facing the central portion 10 </ b> C of the conical bottom portion (bottom surface) 10 </ b> A whose center is gradually narrowed. Concentration for supplying air to the concentrated sludge extraction pipe 15 between the support base 16 and the concentrated sludge extraction pipe 15 is attached to the lower surface of the support base 16 and the lower end is connected to the lower part of the concentrated sludge extraction pipe 15. A sludge extraction pump air pipe 17 is provided.

  The sludge concentration tank 10 is provided with a sludge concentration device 2. The concentrating device 2 includes a gantry 21 attached to the upper side of the upper opening 10B, a motor (driving device) 22 with a continuously variable transmission installed on the gantry 21, and a motor 22 with a continuously variable transmission. A worm speed reducer (drive device) 23 connected to the output shaft, connected to the output side of the worm speed reducer 23, penetrates the concentrated sludge extraction pump 14 and the concentrated sludge extraction pipe 15 from the output side, and a lower end 24A A metal rod-like rotary shaft 24 extending downward from the concentrated sludge extraction tube 15 and facing the center portion 10C of the bottom portion 10A is provided.

  Further, the sludge concentrating device 2 is bent between the lower end 24A of the rotary shaft 24 and the lower end 15A of the concentrated sludge extraction pipe 15 with the lower end connected to the rotary shaft 24 along the inclination of the conical bottom portion 10A. Metal bars 25 (25A to 25C) each having a bent portion and a vertical rod portion that is continuous with the bent portion and rises vertically in a straight line are arranged at equal intervals in the circumferential direction of the rotary shaft 24. A plurality (three in this embodiment) are provided. These bar members 25A to 25C are provided with annular reinforcing pipes (reinforcing members) 26A and 26B that connect and reinforce these bar members 25A to 25C in two lateral directions. A guide 27 is provided between the reinforcing pipes 26 </ b> A and 26 </ b> B to smoothly rotate the rods 25 </ b> A to 25 </ b> C around the rotation shaft 24. The guide 27 includes an annular member 28 loosely fitted on the outer periphery of the concentrated sludge extraction pipe 15, and a connecting member 29 that connects and connects the annular member 28 and the rods 25A to 25C. Even if an external force is applied to the rods 25A to 25C or the rotating shaft 24, the guide 27 restricts the swinging of the rotating shaft 24 and prevents the rotating shaft 24 from shaking because the inner surface of the annular member 28 is regulated by the outer surface of the concentrated sludge extraction pipe 15. Is always kept in the vertical direction. The low concentration liquid path forming means includes a motor 22 with a continuously variable transmission, a worm speed reducer 23, a rotating shaft 24, and rods 25A to 25C.

By the way, the sludge concentrating device 2 according to the present embodiment cuts the upper ends 30 of the rods 25A to 25C into a short length so as to be always submerged under the water surface L1 of the liquid to be treated introduced into the sludge concentrating tank 10. It is formed. More specifically, the upper ends 30 of the rods 25A to 25C are set so as to be approximately half the height of the design water level L1 of the liquid to be treated or slightly higher than approximately half the height. That is, in the sludge concentration tank 10, as the treatment time elapses, the layer of the desorbed liquid Lsp having a lighter specific gravity compared to the high-concentration sludge from the height of approximately half of the design water level L1 to the lower side increases. A layer of high-concentration sludge liquid Lth having a relatively heavy specific gravity containing sludge content is formed, and concentrated sludge is deposited on the bottom 10A. Therefore, the upper end 30 of the bar 25A~25C is never exposed on the water surface L1, it adapted to close the lower side of either the layer positioned in a layer of releasing liquid Lsp. That is, the thickness of the upper end 30 of the rods 25A to 25C is constant while the thickness of the layer of the desorbing liquid Lsp changes according to the processing time.

  In the sludge concentrating device 2, when the motor 22 with a continuously variable transmission is rotationally driven and the output of the motor 22 is decelerated by the worm speed reducer 23 and output to the rotating shaft 24, the rotating shaft 24 becomes the bar 25A. ˜25C is slowly rotated in the liquid to be treated. In this embodiment, for example, the worm speed reducer 23 has a 1:30 reduction output, and the rotation speed output to the rotary shaft 24 is 0.074 to 0.11 rpm. When the rods 25A to 25C rotate slowly in the liquid to be treated, as shown in FIG. 3A, the liquid is caused by a negative pressure on the rear side in the traveling direction of the rods 25 (25A to 25C) in the liquid to be treated. A path P1 having a low concentration is formed. Here, the low liquid concentration means that a liquid component having a light specific gravity is collected in the negative pressure part as compared with a high concentration sludge component, and that the path P1 having a low liquid concentration is formed is a bar. 25 (25A to 25C) means that a liquid component having a low specific gravity gathers in the longitudinal direction (vertical direction) along the rod 25 on the rear side in the traveling direction, and the liquid component having a low specific gravity is formed in the vertical direction. That is, when the path P1 having a low liquid concentration is formed on the rear side in the traveling direction of the bar 25 (25A to 25C), the liquid having a low liquid concentration collected in the path P1, that is, the liquid having a small amount of sludge is more specific gravity. It moves to the lighter side, and an upward flow is generated, and a water channel is formed. Since the layer of the desorbing liquid Lsp is formed at the level above the upper end 30 of the rod 25 (25A to 25C) or at the level where the upper end 30 is located, the liquid with a low liquid concentration rising on the path P1 is desorbed. The formation of the layer of the desorption liquid Lsp is accelerated by joining the liquid Lsp.

  Next, the sludge concentration method according to the present invention will be described based on the action of the sludge concentration apparatus 2 according to the above embodiment. In the sludge concentration apparatus 2 according to the present embodiment, when the excess sludge Lsl extracted from the aeration tank 6 by the sludge extraction pump 12 is guided to the sludge concentration tank 10 and reaches the design water level L1, the operation of the sludge extraction pump 12 is performed. Stop. The motor 22 with a continuously variable transmission is always in operation, and when a rotational driving force is output to the rotating shaft 24 via the worm reducer 23, the rotating shaft 24 slowly moves the rods 25A to 25C in the liquid to be processed. And rotate. At this time, a path P1 having a low liquid concentration is formed by the negative pressure on the rear side in the traveling direction of the rods 25A to 25C. In this path P1, the liquid component having a low liquid concentration and a low specific gravity rises and flows out to the upper side in the liquid to be treated. For this reason, a layer of the desorbed liquid Lsp separated into solid and liquid is formed in the liquid to be treated, and a liquid component having a low liquid concentration and a low specific gravity is constantly supplied upward from the path P1 having a low liquid concentration. Therefore, the layer of the desorbing liquid Lsp is formed in a short time, and the thickness of the layer increases rapidly. For this reason, in the sludge concentration tank 10, separation of the desorbed liquid Lsp and the concentrated sludge can be performed in a pipe time, and the working efficiency is improved. Further, since the rods 25A to 25C are always submerged below the water surface L1, there is no possibility of causing turbulent flow on the water surface L1, and the formation of the desorbed liquid Lsp is hardly affected.

  In the above embodiment, three rods 25 are provided at equal intervals in the circumferential direction of the rotating shaft 24, but the present invention is not limited to this, and three or more rods may be provided. Further, the bar 25 may be provided in double, triple and multiple with respect to the rotating shaft 24.

Next, a verification test was conducted with a concentration device substantially including the structure of the sludge concentration device 2 according to the above example. The results of the verification test are shown below.
1. Verification Test Conditions The verification test of the concentration test apparatus was conducted at an actual treatment facility in the Kanto region shown in Table 1. In the verification test, surplus sludge, concentrated sludge, desorbed liquid, etc. were sampled and analyzed once a week to confirm the sludge concentration performance. In Table 2, experiment NO. And the relationship between the experimental conditions.

2. Investigation results of demonstration test Water quality analysis of (1) surplus sludge, (2) extracted sludge, and (3) desorbed liquid collected during the demonstration test period was conducted. The analysis items are three items of sludge, pH, MLSS, and MLVSS, and the desorption solution is three items of pH, BOD, and SS. Table 3 shows the state of sludge concentration in the sludge concentration tank. Table 4 shows the properties of the desorbed liquid.

In RUN1 (without a sludge concentrator), the sludge with an excess sludge concentration of 4,380 mg / L was 7,490 mg / L after the sludge concentration, and the concentration factor was 1.71 times.
On the other hand, in RUN2 with a sludge concentrator, the sludge with an excess sludge concentration of 7,230 mg / L was 26,530 mg / L after the sludge concentration, and the concentration factor was 3.68 times.
There was no significant difference between RUN1 and RUN2 in terms of the properties of the desorbed solution, and good desorbed solutions were obtained for both.
From the results of demonstration tests at these facilities, when the sludge concentration device according to this example was installed, the sludge concentration in the sludge concentration tank was increased and the sludge concentration was increased without causing deterioration of the desorbed liquid. It was found that the effect of increasing the magnification was great. Thereby, it was confirmed that the concentration effect of sludge increases by this concentration apparatus.

2 Sludge Concentrator 10 Sludge Concentration Tank 25A-25C Bar 30 Upper end of Bar P1 Low liquid concentration path L1 Water level of liquid to be treated Lsp Desorbed liquid

Claims (4)

It is a sludge concentration tank with a hopper structure that constitutes a purification process for sludge or wastewater, and is disposed vertically in a sludge concentration tank that separates the liquid to be treated into a detachment liquid and a concentrated sludge. A plurality of bar members are arranged, and a low-concentration liquid path forming means for forming a low-concentration liquid channel by negative pressure is provided on the rear side in the traveling direction of the bar members in the liquid to be treated. And
The upper ends of these bars are cut into short lengths so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank,
In the central part of the sludge concentration tank, a concentrated sludge extraction pipe connected to the concentrated sludge extraction pump is arranged and configured.
The low-concentration liquid path forming means includes a rotating shaft that protrudes upward from the concentrated sludge extraction pipe and is connected to the rotary drive device, and has a lower end that extends downward from the concentrated sludge extraction pipe and faces the bottom surface.
The bar has a lower end connected to the lower part of the rotating shaft and has a connecting part extending along the inclination of the conical bottom, and a vertical bar part that is continuous with the connecting part and rises upward.
A method for concentrating sludge, characterized in that, during solid-liquid separation treatment, a rod is rotated to form a path with a low liquid concentration in the longitudinal direction in the liquid to be treated. A sludge concentrating tank with a hopper structure that forms part of the purification process of sewage or wastewater, and in the longitudinal direction, into the sludge concentrating tank that separates the liquid to be treated into separated liquid and concentrated sludge. A low-concentration liquid path forming means that arranges a plurality of arranged bars and rotates these bars to form a path with low liquid concentration by negative pressure on the rear side in the traveling direction of the bars in the liquid to be treated. While providing and configuring,
The upper ends of these bars are cut into short lengths so that they are always submerged under the surface of the liquid to be treated introduced into the sludge concentration tank ,
In the central part of the sludge concentration tank, a concentrated sludge extraction pipe connected to the concentrated sludge extraction pump is arranged and configured.
The low-concentration liquid path forming means includes a rotating shaft that protrudes upward from the concentrated sludge extraction pipe and is connected to the rotary drive device, and has a lower end that extends downward from the concentrated sludge extraction pipe and faces the bottom surface.
The bar has a lower end connected to the lower part of the rotating shaft and has a connection part extending along the inclination of the conical bottom part, and a vertical bar part that is continuous with the connection part and rises upward. A sludge concentrator. The sludge concentrating device according to claim 2, wherein the upper end of the bar is set to a height substantially half of the design water level of the liquid to be treated.   4. The guide according to claim 3, further comprising a guide configured by connecting the rod members with a reinforcing material, loosely fitting an annular member around the outer periphery of the concentrated sludge extraction pipe, and connecting the annular member and the rod member. The sludge concentration apparatus as described.

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