JP2002361003A - Flocculating and settling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flocculating and settling apparatus, in which the clogging of a distributor is prevented even if the operation is suspended through a long period or the starting and stopping is frequently carried out and which is easily cleaned even if being clogged to eliminate the cause of the clogging and to restart the operation. SOLUTION: In the sludge blanket type flocculating and settling tank provided with a center column 14 in a settling tank and a plurality of radial distributors 15 horizontal and turnable, each of which is provided with a hollow feed water supply port 17 for discharging feed water flowing in the inside from the center column to a sludge blanket layer 11 on the bottom of the settling tank around the lower center part of the center column, a cleaning pipe 21 facing in the direction of the tip of the distributor is mounted in the branched part 14' of the distributor inside the lower end of the center column and sludge deposited on the branched part and the inside of the distributors are cleaned with cleaning water spouting from the cleaning pipe to prevent the clogging of the distributor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a center column provided in a settling tank (thickener), and a hollow raw material (coagulant, coagulant) supplied from the center column to the inside around the lower end of the center column. A plurality of radial distributors having a raw water supply port for discharging the sludge mixed liquid) into the sludge blanket layer at the bottom of the settling tank are provided so as to be able to turn horizontally. Separation of suspended solids and fine SS in raw water discharged from the facility by filtration through a sludge blanket layer, and concentration of the sludge layer including newly generated sludge with a mud collecting member (rake) that rotates together with the distributor, and settling tank Sludge blanket-type coagulation that drains sludge from the center of the bottom and allows clear treated water to overflow from the upper end of the settling tank Relates gluteal apparatus, especially wash the sludge deposited on the bifurcation of the distributor at the bottom of the center column, and to prevent the clogging of the distributor.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 10-2 proposed by the present applicant.
According to Japanese Patent Publication No. 02009, a distributor having a hollow raw water supply port for discharging raw water supplied inside into a sludge blanket layer is provided horizontally horizontally in a sludge blanket layer at the bottom of a settling tank. A sludge blanket type coagulation sedimentation device is known.

[0003]

Although the above-mentioned known coagulation and sedimentation apparatus achieves the desired effects to some extent, the following problems may be pointed out when problems are pointed out. Conventionally, factory wastewater to be treated by the coagulation sedimentation apparatus is often continuously supplied day and night, so that the distributor is hardly blocked. Recently, however, many factories have reduced their operation level on Saturdays and Sundays, and more and more factory wastewater has not been discharged on Saturdays and Sundays. Also, from the viewpoint of space saving, the capacity of the raw water regulating tank is often designed to be small, and accordingly, the operation of the coagulation sedimentation tank is turned ON / OFF.
Is becoming more frequent.

[0004] As a result, the SS in the column and the SS of the coagulated raw water flowing into the center column due to the water level difference even after the pump is stopped are provided at the bottom of the center column, which is mounted radially around the distributor. When the sedimentation is repeated, the sludge is piled up as shown by a broken line in FIG. 1 and a sedimentary sludge zone grows. In this case, the raw water is not supplied from the center column to the raw water supply port of the distributor, and eventually the raw coagulated water overflows from the upper end of the center column into the settling tank. Therefore, the solid-liquid separation performance decreases, SS increases in the treated water, and the quality of the treated water deteriorates.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been developed to solve the above-mentioned problems. A center column is provided in a settling tank, and a hollow center is formed around the lower end of the center column. In a sludge blanket-type coagulating sedimentation apparatus provided with a plurality of radial distributors having a raw water supply port for discharging raw water flowing into the inside from a center column into a sludge blanket layer at the bottom of a settling tank, the horizontal distributor being capable of turning horizontally. At the branch with the distributor inside the lower end of the center column, install a washing pipe facing the tip of the distributor, and wash the sludge and the inside of the distributor that are deposited on the branch with the washing water squirting from the washing pipe, The blockage of the distributor is prevented. The washing pipe is preferably composed of a high-speed washing pipe having a high jet flow rate of the washing water, and a low-speed washing pipe having a slow jetting flow rate but a larger amount of jet water than the high-speed washing pipe. It is preferable that the washing water can be spouted from the washing tube continuously or periodically, and that the washing water can be spouted even when the apparatus is operating or stopped. Further, the center column and the distributor may be integrally rotated, or the center column may not be rotated, and only the distributor may be rotated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 10 denotes a cylindrical sedimentation tank having a mortar-shaped bottom, on which a sludge blanket layer 11 is deposited. The settling tank has a pit 12 at the center of the bottom, and a drain pipe 13 is connected to the pit. Reference numeral 14 denotes a center column which is supported vertically along the center of the settling tank 10 and has a lower end reaching the inside of the sludge blanket layer 11 and an upper end protruding upward from the water surface of the settling tank and stirring the flocculant in a flocculating tank or the like. The mixed raw water flows into the upper end of the center column.

At the lower end of the center column, a plurality of hollow distributors 15 are provided horizontally and radially at a phase of 90 ° in the figure in communication with the inside of the lower end of the center column. In the embodiment shown, the center column passes through the center of the inside, and the lower end is formed in the pit 12.
Are fixed to a vertical drive shaft 16 received at the bottom of the motor, and are rotated at a low speed in one direction integrally with the distributors 15 by a motor and a reduction gear M for rotating the drive shaft. Each distributor 15 is provided with a raw water supply port 17 for discharging raw water flowing into the center column into the sludge blanket layer 11. In FIG. 1 (A), raw water supply port 1
Although 7 is shown as a plurality of round openings provided at intervals in the longitudinal direction of the distributor, the shape is not limited to a round shape and may be a series of rectangles continuous in the longitudinal direction. The drive shaft 16 has a distributor 15.
, A plurality of rakes 18 rotating in contact with the bottom surface of the settling tank are fixed radially.

When the center column 14, the distributor 15, and the rake 18 are rotated at a low speed inside the settling tank 10 by the drive shaft 16, the raw water flowing into the center column from above flows down the inside of the center column and radially branches. The raw water is guided into each of the distributors, discharged from the raw water supply port 17 into the sludge blanket layer 11, and SS in the raw water is captured by the sludge blanket layer, and treated water containing no SS flows upward from the sludge blanket layer. Overflow gutter 19 provided around the upper end of the settling tank
, And is taken out of the system from the take-out tube 20. The sludge located on the bottom of the settling tank is swept into the pit 12 by the rotation of the rake 18 and is discharged from the mud pipe 13 to the outside of the system.

As described above, the SS in the raw water in the center column is deposited at the bottom of the center column, piled up in a mountain shape, and the raw water is no longer diverted from the center column to each distributor, and the distributor is blocked. In order to prevent the distribution, the distributor 15 is provided at the branch portion 14 'with the distributor inside the lower end of the center column.
A washing pipe 21 facing the tip of the washing pipe is installed, and the sludge deposited on the branch portion is washed and removed with washing water spouted from the washing pipe, and the inside of each distributor is washed.

The washing tube 21 is fixed and the center column 14
Of the pipe 21 from the upper end, the distal end 21 'of the pipe 21 is bent at a substantially right angle at the branch part 14' with the distributor, and faces toward the distal end of the distributor. When the cleaning liquid is pressurized and injected into the cleaning pipe 21, the inner circumference at the bottom of the center column, which rotates integrally, and the distributor directed to the tip 21 'of the cleaning pipe are sequentially sprayed with the cleaning water. As a result, the mountain-shaped settling sludge zone deposited on the bottom of the center column is destroyed and eliminated, and at the same time, the entire circumference of the branch portion with the distributor and the hollow interior of each distributor are washed with washing water.

In the illustrated embodiment, as shown in FIG. 2, the cleaning pipe 21 has a small diameter at the tip for jetting the cleaning water.
Accordingly, the high-speed washing pipe 21A having a high jet flow rate of the washing water, and the diameter of the tip for jetting the washing water being larger than the diameter of the high-speed washing pipe. And a tube 21B.

The low-speed washing pipe 21B is directed toward the upper side of the inside of the distributor, and its injection flow rate is 5 to 15 m / sec. The sedimentation sludge zone mainly deposited on the upper part of the branch portion of the distributor of the center column is broken and eliminated. The inner circumference at the bottom of the center column is washed, and the washed sludge is distributed to a distributor with a large amount of washing water and poured.

On the other hand, the high-speed washing pipe 21A is directed near the lower side of the inside of the distributor, and its injection flow rate 20
The washing water is sprayed at a high speed of about 25 m, and the washing water also breaks down the settling sludge zone and cleans the inner periphery of the bottom of the center column. And the sludge flowing into the distributor is discharged out of the raw water supply port 17.

In this way, the blockage of the distributor can be effectively prevented by using the high-speed washing pipe 21A having a high jetting flow rate of the washing water and the low-speed washing pipe 21B having a small jetting flow rate and a large jetting rate of the washing water. Can be prevented.

Even if the number of washing tubes is one, as described above,
It may be a book or a plurality of three or more books. If no sludge is deposited on the upper part of the distributor branch, only the high-speed washing pipe 21A may be used.

As the washing water, any of industrial water, tap water and treated water taken out of the apparatus may be used.

[0017] The supply of the washing water to the washing tube may be continuous or intermittent. In the case of intermittent supply, a timer is used for a predetermined period of time, for example, 6 to
Supply wash water every 12 hours for 5-15 minutes. Further, it may be supplied during the operation (ON) or during the suspension (OFF) of the coagulation / sedimentation apparatus, or may be supplied only during the suspension. When the coagulating sedimentation apparatus is frequently operated (ON, OFF), it is preferable to supply washing water intermittently at all times, regardless of whether the apparatus is operating or stopped, to prevent sludge deposition and prevent sludge deposition. Discharge. When suspending for a long time, the cleaning water may be supplied continuously or intermittently only during the suspension period.

In the illustrated embodiment, a plurality of distributors are radially provided around the bottom of the center column, and the center column, the distributor, and the rake are integrally rotated in one direction. However, the present invention is not limited to this.
The center column is composed of a center column bottom with a distributor arranged radially around it and a column body above this bottom and connected by a swivel joint or the like, and the column body is appropriately supported in a sedimentation tank so that it cannot rotate. The center column bottom with the distributor and the rake may be rotated in one direction by the drive shaft 16.

[0019]

According to the present invention, even if the apparatus is stopped for a long time or the apparatus is frequently started and stopped, and the distributor is blocked by sludge, the sludge deposited due to the blockage can be easily cleaned. It can be removed and the operation can be carried out as before, and also the cleaning can be performed prophylactically so that no blockage occurs.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of one embodiment of the coagulation and sedimentation apparatus of the present invention, and FIG. 1B is a sectional view taken along the line BB in the above.

FIG. 2 is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Sedimentation tank 11 Sludge blanket layer 12 Pit 13 Drainage pipe 14 Center column 14 'Branch part of center column with distributor 15 Distributor 16 Drive shaft 17 Distributor raw water supply port 18 Rake 19 Overflow gutter 20 Extraction pipe 21 Washing pipe 21 'Tip of washing tube 21A High-speed washing tube 21B Low-speed washing tube

Claims (6)

[Claims] 1. A raw water supply in which a center column is provided in a settling tank and raw water which is hollow and flows into the inside from the center column is discharged around a lower end of the center column into a sludge blanket layer at the bottom of the settling tank. In a sludge blanket-type coagulation and sedimentation device provided with a plurality of radial distributors having ports that can be swiveled horizontally, a washing pipe facing the tip of the distributor is installed at the branch of the center column at the lower end with the distributor. A coagulation sedimentation apparatus characterized in that sludge deposited on the branch portion and the inside of the distributor are washed with washing water spouted from the washing pipe to prevent the distributor from being blocked. 2. The coagulating sedimentation apparatus according to claim 1, wherein the washing pipe comprises a high-speed washing pipe having a high jet flow rate of the washing water, and a low-speed washing pipe having a slow jetting flow rate but a larger amount of jet water than the high-speed washing pipe. A coagulation sedimentation apparatus comprising: 3. The coagulating sedimentation apparatus according to claim 1, wherein the washing water can be ejected from the washing pipe continuously or periodically. . 4. The coagulating sedimentation apparatus according to claim 3, wherein the washing water can be ejected even during operation of the apparatus or at rest. 5. The coagulating sedimentation apparatus according to claim 1, wherein the center column and the distributor rotate integrally. 6. The coagulating sedimentation apparatus according to claim 1, wherein the center column does not rotate and the distributor rotates.