JP2002239598A - Sludge dehydration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge dehydration apparatus having a stable dehydration capacity regardless of the SS concentration of the treated sludge even when a multiple disc dehydrator is employed. SOLUTION: The sludge dehydration apparatus includes the multiple disc type dehydrator 1 and the gravity filtering type filtrate separation means 20 provided on the upstream side of the multiple disc type dehydrator 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge dewatering apparatus using a multi-disc dehydrator.

[0002]

2. Description of the Related Art Conventionally, as a dewatering method in sludge treatment, a vacuum method, a pressure method, or a centrifugal method is known. However, such a method requires large power, has many consumables, requires maintenance, and it is difficult to stably treat oil-containing sludge. On the other hand, if a so-called multi-disc dehydrator is adopted, it has low power, few consumables, and requires almost no maintenance.
Oil-containing sludge can also be treated stably. However, the multi-disc dehydrator has a drawback that if the concentration of the treated sludge is low and the generation of floc is not sufficient, the dewatering performance is inferior.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. Even when a multi-disc dehydrator is employed, a stable dehydration performance can be obtained regardless of the SS concentration of the treated sludge. An object of the present invention is to provide a sludge dewatering device that can be expected.

[0004]

In order to achieve the above object, a sludge dewatering apparatus according to the present invention comprises a multi-disc dehydrator and a gravity filtration type dehydrator provided upstream of the multi-disc dehydrator. And a filtrate separation means. The gravity filtration type filtrate separation means may be a means for separating the filtrate by gravity. Although not particularly limited, means having a relatively simple configuration such as an inclined screen is preferable. The objects to be treated by the sludge dewatering apparatus according to the present invention are organic wastes such as night soil and septic tank sludge, and excess sludge generated when these are activated sludge treatment. In the present specification, sludge is used as a concept including such a treatment target widely.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sludge dewatering apparatus according to the present invention will be described below with reference to an embodiment shown in the accompanying drawings. 1 to 5 show an embodiment of a multi-disc dehydrator as one component of the sludge dewatering apparatus according to the present invention.

As shown in FIG. 1, a multi-disc dehydrator 1
Includes a coagulation tank 2 and a dehydration tank 3. Coagulation tank 2
This is a tank for mixing a dehydration aid with sludge to form flocs. A stirring blade 4 for stirring and mixing the dehydration aid and the sludge is provided, and the stirring blade 4 is rotated by a driving device (not shown). The coagulation tank 2 and the dewatering tank 3 communicate with each other through a communication channel 5 provided above the coagulation tank 2.

[0007] The dewatering tank 3 is a device for dewatering sludge containing flocs. The dewatering tank 3 includes an upper filter body 6 and a lower filter body 7. And, the dewatered cake outlet 8 is provided at the most downstream. Both the upper filter body 6 and the lower filter body 7 are composed of a large number of disks. Each of the filter bodies 6 and 7 comprises a large-diameter disk 9 shown in FIG. 2 and a small-diameter disk 10 shown in FIG. A plurality of (eight in this embodiment) filtrate holes 11 are formed in the disc 9, and a plurality of (eight in this embodiment) are formed on the circumference of the disc 10.
A filtrate groove 12 is provided. As shown in FIGS. 4 (a) and 4 (b), the filter unit 13 constituting each of the filter bodies 6 and 7 is constructed by alternately arranging the disks 9 and 10 on the rotating shaft 14 so as to be adjacent to each other. It is configured. Then, adjacent filter units 13 are arranged such that the disk 9 and the disk 10 face each other, and a slit S is formed between the adjacent disks 9.

When the filter unit 13 is rotated, the sludge is formed into a dewatered cake while being dewatered by the slit S, and is conveyed toward the dewatered cake outlet 8. Since the filtrate that has passed through the slit S is provided with the filtrate hole 11 and the filtrate groove 12 provided in the disks 9 and 10, it is configured to flow through these and flow into the filtrate drainage unit 15 shown in FIG. The filtrate drainage section 13 is provided on a side surface of the dewatering tank 3. This filtrate is drained to the outside. Thereafter, it can be sent to a subsequent processing device such as an advanced processing device (not shown).

As shown in FIG. 4, the disk 9 is rotated while being engaged in the slit S of the filtration surface, thereby continuously cleaning the slit S and constantly regenerating a new filtration surface. ing. As shown in FIG. 1, the distance between the upper filter body 6 and the lower filter body 7 decreases toward the downstream, and
The dehydration cake is configured so that a compressive force acts on it. Also,
The higher the number of rotations, the higher the speed. This also creates a compressive force. These compressive forces promote dewatering filtration. The dewatered cake is discharged from the dewatered cake outlet 8 and carried out on a chute.

Due to the structure of the filter bodies 6 and 7 as described above, no clogging occurs on the filter surface. However, if there is a floating substance flowing out of the filtrate, the filtrate hole 11 may be closed. On the other hand, in the present embodiment, a filtrate washing means is provided as shown in FIG. That is, a filter washing nozzle 16 is provided for each of the filter bodies 6 and 7, and the filtrate hole 11 is washed once every two to three hours by a pump (not shown). Wash water spouted from the filter washing nozzle 16 flows through the filtrate hole 11 and the filtrate groove 12 to wash the filtrate hole 11. In addition, in order to perform washing efficiently, it is preferable that the pitch of the filtrate hole 11 and the filtrate groove 12 be the same, and that their mutual positions match. This cleaning can be performed under appropriate control by a controller (not shown). The multi-disc dehydrator 1 according to the present embodiment is provided with a drive device, a controller, and the like for each of the filter bodies 6 and 7 (not shown) that are well-known to those skilled in the art that are required for operation.

The sludge dewatering apparatus according to the present invention is characterized in that a gravity filtration type filtrate separation means is provided upstream of the multiple disc dehydrator described in the above embodiment. The relationship between the gravity filtration type filtrate separation means and the multiple disc dehydrator will be described with reference to FIG. That is, FIG.
1 shows an embodiment of a sludge dewatering apparatus according to the present invention. The sludge treatment apparatus includes a gravity filtration type filtrate separation means 20 and a multiple disc dehydrator 1. Gravity filtration type filtrate separation means 20
Is a screen 21 which is arranged obliquely as shown.
The screen 21 is a metal net having a mesh width of 0.1 mm to 1 mm. In the screen 21, the sludge 22 flows along the inclined surface by its own weight, and the contained water is discharged as the filtrate 23. The gravity filtration type filtrate separation means 20 has a simple configuration using a screen 21, is excellent in that it is not an excessive device and does not require power.

Next, a procedure for dewatering sludge using the embodiment of the sludge dewatering apparatus according to the present invention described with reference to FIGS. 1 to 6 will be further described. First, the sludge 22 is supplied onto the screen 21 from above the screen 21 of the gravity filtration type filtrate separation means 20 shown in FIG. The sludge 22 on the screen 21 flows along the inclined surface of the screen 21,
Head to the multi-disc dehydrator 1. On the other hand, the water contained in the sludge 22 passes through the screen 21 as the filtrate 23.
The filtrate 23 may be further processed as required (advanced processing, etc.)
Is given. Since the sludge 22 is dewatered by gravity in this manner, the sludge 22 is supplied to the multi-disc dehydrator 1 while being converted into concentrated sludge 24 having an increased SS concentration.

Next, as shown in FIG. 1, in the flocculation tank 2, a dewatering aid is mixed with sludge to form flocs. By the gravity filtration type filtrate separation means 20 at the previous stage, SS
Because of the increased concentration, the amount of dehydration aid used is greatly reduced even at very low initial SS concentrations. That is, even if the sludge has a low SS concentration, there is no problem in employing the multiple disc dehydrator. In addition, since the SS concentration can be adjusted in advance in this way, even when the SS concentration varies, the operating state of the multiple disc dehydrator 1 can be kept constant, and stable dehydration performance can be expected. . That is, the dehydration performance of the multiple disc dehydrator 1 itself is improved,
In addition, since the volume of the entire sludge is reduced, the throughput itself is also reduced. In addition, examples of the dehydration aid to be used include a cationic or anionic polymer flocculant and an inorganic flocculant such as a sulfate band, but are not limited thereto. In addition, such a dehydration aid can be added before the gravity filtration type filtrate separation means 20 for increasing the dehydration efficiency. Of course, gravity filtration type filtrate separation means 20
Can be added both in the former stage and in the coagulation tank 2.

The dehydration aid and the sludge 24 are stirred and mixed in the flocculation tank 2 by the stirring blade 4. Then, the sludge 24 in which the flocs are sufficiently formed is guided to the dewatering tank 3 from the communication channel 5 provided above the flocculation tank 2.

In the dewatering tank 3, the sludge 24 containing flocs is dewatered. By rotating the filter units 13 of the upper and lower filter bodies 6 and 7, the sludge 24 becomes a dewatered cake 25 while being dewatered by the slit S (FIG. 4), and is conveyed toward the dewatered cake outlet 8. . The filtrate that has passed through the slit S is supplied to the filtrate holes 11 and the filtrate grooves 1 provided in the discs 9 and 10.
2 and flows into the filtrate drainage section 15 shown in FIG. This filtrate is drained to the outside. Thereafter, it can be sent to a subsequent processing device such as an advanced processing device (not shown).

As shown in FIG. 4, the disk 9 rotates while biting into the slit S of the filtration surface, thereby continuously cleaning the slit S and constantly regenerating a new filtration surface.
As shown in FIG. 1, the upper filter body 6 and the lower filter body 7 are configured such that the distance between them becomes smaller toward the downstream, and a compressive force acts on the dewatered cake. In addition, the number of rotations is set higher toward the upstream. This also creates a compressive force.
These compressive forces promote dewatering filtration. Therefore, the sludge 24 is satisfactorily dewatered. The dehydrated cake 25
It is discharged from the dewatering cake outlet 8 and carried out on a chute (not shown).

Due to the structure of the filter bodies 6 and 7 described above, no clogging occurs on the filter surface. However, if there is a floating substance flowing out of the filtrate, the filtrate hole 11 may be closed. In this embodiment, washing water is supplied to a filter washing nozzle 16 provided for each of the filter bodies 6 and 7 by a pump (not shown), and the filtrate hole 11 is washed once every two to three hours. Wash water spouted from the filter washing nozzle 16 flows through the filtrate hole 11 and the filtrate groove 12 to wash the filtrate hole 11. By setting the pitch of the filtrate hole 11 and the pitch of the filtrate groove 12 to be the same and making their positions coincide with each other, the washing water flows at a stretch and washing is performed efficiently. This cleaning is performed under appropriate control by a controller (not shown).

Other Embodiments As described above, the sludge dewatering device according to the present invention has been described with respect to the embodiment shown in FIGS. 1 to 6, but the present invention is limited to this embodiment. Without departing from the scope of the present invention, all changes, additions and modifications obvious to those skilled in the art are included in the technical scope of the present invention. Although the gravity filtration type filtrate separation means is an inclined plate screen, the invention is not limited to this. For example, a drum-shaped screen or a basket-shaped screen may be used.

[0019]

As is apparent from the above description, according to the present invention, even when a multi-disc dehydrator is employed, stable dehydration performance can be expected regardless of the SS concentration of the treated sludge. A sludge dewatering device is provided.

[Brief description of the drawings]

FIG. 1 is a conceptual partially cutaway sectional view showing an embodiment of a multi-disc dehydrator employed in a sludge dewatering apparatus according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a large-diameter disc employed in the multiple disc dehydrator of FIG. 1;

FIG. 3 is a perspective view showing an embodiment of a small-diameter disc employed in the multiple disc dehydrator of FIG. 1;

FIGS. 4A and 4B are views for explaining an embodiment of a filter unit employed in the multiple disc dehydrator of FIG. 1, wherein FIG. 4A is a plan view and FIG. 4B is a side view.

FIG. 5 is a cross-sectional view cut along a plane including upper and lower rotating shafts of a filter body unit.

FIG. 6 is a conceptual diagram illustrating an embodiment of a gravity filtration type filtrate separation means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-disc dehydrator 2 Coagulation tank 3 Dehydration tank 4 Stirrer blade 5 Communication channel 6 Upper filter 7 Lower filter 8 Dewatering cake outlet 9, 10 Disk 11 Filtration hole 12 Filtrate groove 13 Filter body unit 14 Rotating shaft 15 Filtrate drainage part 16 Filtrate washing nozzle 20 Gravity filtration type filtrate separation means 21 Screen 22 Sludge 23 Filtrate 24 Concentrated sludge 25 Dewatered cake

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Mizutani 12 Nishikicho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Heavy Industries, Ltd. (72) Inventor Kazuhiko Fujise 12 Nishikicho, Naka-ku, Yokohama-shi, Yokohama F term in Yokohama Works (reference) 4D026 BA03 BB01 BC01 BC39 BE11 BE14 BF06 BF09 4D059 AA01 AA02 AA05 BE02 BE07 BE55 BE57 BE59 BJ01 DA35 DB11

Claims (3)

[Claims] 1. A sludge dewatering apparatus including a multi-disc dehydrator and a gravity filtration type filtrate separation means provided upstream of the multi-disc dehydrator. 2. A sludge dewatering apparatus according to claim 1, wherein said gravity filtration type filtrate separation means is an inclined screen. 3. The sludge dewatering apparatus according to claim 1, wherein a dehydration aid is added before the gravity filtration type filtrate separation means.