JP2001252698A - Sludge thickening method and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance sludge thickening efficiency to excess sludge successively increasing in its amount and recovery efficiency thereof in stages of a secondary treatment and primary treatment of a sewage treatment. SOLUTION: In the process of scooping up the excess sludge of a treating vessel by mesh trays and scooping up the same out of the treating vessel, the scooped excess sludge is subjected to a draining treatment and the thickened sludge remaining in the meshed trays is fed into a sludge storage tank. In terms of the device, the mesh trays for scooping up the excess sludge are mounted at an elevator conveyor device, rotary water wheel and swing arm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for sludge concentration of surplus sludge which is gradually increased at the stage of activated sludge treatment.

[0002]

2. Description of the Related Art Conventionally, when a secondary treatment apparatus for sewage treatment is a treatment tank of a membrane separation activated sludge treatment system, a batch activated sludge treatment tank, or the like (hereinafter, referred to as an activated sludge treatment tank), the activated sludge is used. Due to the excess sludge gradually increasing with the progress of the treatment, the treatment load increases and the sewage performance gradually decreases.

[0003] Therefore, in small- and medium-sized sewage treatment facilities, excess sludge is pumped into a sludge concentration storage tank by an air lift function of a sludge drawing pipe for an air lift, a submersible pump, etc., and solid-liquid separation is performed by gravity sedimentation. Dealing with storage.

[0004] In a large-scale sewage treatment facility, excess sludge pumped is stored in a sludge storage tank through a sludge concentration facility.

[0005] When a sludge dewatering machine is incorporated as a sludge concentration facility, it is meaningful in a large-scale sewage treatment facility where a large amount of excess sludge is generated on a daily basis, but in a relatively small-scale facility, it is meaningful. The sludge will be pumped up to a sludge concentration storage tank, subjected to solid-liquid filtration, the desorbed liquid will be returned, and the concentrated sludge will be transported to a terminal treatment facility for treatment.

[0006]

At this time, when the sludge stored in the sludge concentration storage tank is separated into solid and liquid by gravity sedimentation, the residence time for the separation must be sufficiently long. Either reserve capacity or remove the sludge in a short cycle. In this regard, although the concentration efficiency can be increased by adding the coagulant, the additive must be constantly added, and the running cost is also increased.

[0007] In addition, the generated sludge and the treated water in the tank are simultaneously pumped up by an air lift function of a sludge drawing pipe for an air lift or a submersible pump, and then solid-liquid separated in a sludge concentration and storage tank. Since it is returned and reprocessed again, more energy is spent on pumping excess sludge than necessary.

[0008]

Therefore, in the present invention, in order to solve the above-mentioned problems, excess sludge is once pumped into a sludge concentration storage tank and then separated into solid and liquid, or the sludge is concentrated. Rather than once pumped to equipment and dewatering, instead of returning the desorbed liquid for reprocessing, as described in claim 1, scooping out excess sludge from the processing tank,
In the process of lifting up the sludge from the treatment tank, a sludge concentration method is provided in which the excess sludge scooped up is drained, and the remaining concentrated sludge is charged into a sludge storage tank.

According to the second aspect of the present invention, the excess sludge in the treatment tank is scooped into a mesh tray, and in the process of being lifted from the treatment tank, the excess sludge scooped is drained to remove the concentrated sludge remaining in the mesh tray. It is put into the storage tank.

In terms of the device, as described in claim 5,
One of the elevator conveyor devices is immersed and supported in the sludge of the treatment tank, and the other side faces the upper part of the sludge storage tank, and a mesh tray for scooping excess sludge is attached to the elevator conveyor device. I do.

According to a sixth aspect of the present invention, one of the elevator conveyers is immersed and supported in the sludge of the treatment tank, and the other faces the upper part of the sludge storage tank, and the conveyor belt of the elevator conveyer is meshed. As a conveyor,
The sludge concentrator is equipped with a tray for scooping up excess sludge on the mesh conveyor.

According to a seventh aspect of the present invention, the elevator conveyor device is supported substantially vertically in the sludge in the treatment tank, and a mesh tray for scooping up excess sludge is attached to the elevator conveyor device. A discharge chute is provided, and the concentrated sludge from the mesh tray, which reaches the rising end of the elevator conveyor device and turns over, is dropped into the sludge storage tank via the discharge chute.

According to another aspect of the present invention, a rotary turbine driven by a motor is immersed and supported in the processing tank, a mesh tray is mounted on the rotary turbine, and a discharge chute to a sludge storage tank is provided above the rotary turbine, and excess sludge in the processing tank is provided. Sludge concentrator that scoops up and lifts the sludge on the mesh tray and drains it, and when the mesh tray reaches the vicinity of the upper end of the rotary turbine, the concentrated sludge remaining on the mesh tray is dropped from the discharge chute into the sludge storage tank. And

According to a ninth aspect of the present invention, a mesh tray is formed at the tip of a swing arm driven by a motor, and the base end of the swing arm is driven by a motor, thereby pulling up excess sludge in the treatment tank while scooping the sludge on the mesh tray. In this way, a sludge concentrating device is provided in which the sludge is drained, and when the mesh tray reaches the vicinity of the upper end of the swing arm, the swing arm is rapidly rotated to feed the concentrated sludge into the sludge storage tank.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 showing a first embodiment of the present invention, reference numeral 1 denotes an activated sludge treatment tank, and the inside of the tank is contacted and aerated by a diffuser pipe 2 provided at the bottom of the tank. A stirring flow is formed in the direction of the arrow. Numeral 3 denotes an elevator conveyor device, the lower end of which is immersed in the activated sludge of the activated sludge treatment tank 1, and the upper end of which is overhanged on the upper part of the sludge storage tank 4 and is inclinedly supported.

Accordingly, the conveyor belt 5 is stretched over the driving roller 6 at the upper end and the driven roller 7 at the lower end, and the main part of the conveyor belt 5 shown in FIGS. 2A and 2B is enlarged. As shown in the figure, supporting girders 8 are fixed at appropriate intervals, and a mesh-like water-permeable sheet 10 such as a woven or nonwoven fabric is stretched on the supporting girders 8 on a rectangular window frame 9. Or a water-permeable container or saucer which is punched and formed in a porous shape, and is hereinafter referred to as a mesh tray 11.

Reference numeral 12 denotes a vibrating member having a rack 13 protruding therefrom. The vibrating member 12 comes into contact with the tip of the window frame 9 of the rising mesh tray 11 and receives an impact or vibration generated from excess sludge scooped on the mesh tray 11. Improves the draining effect. Reference numeral 14 denotes an impact member having a rack 15 protruding therefrom.
When turning over the mesh tray 11 that has been drained and raised,
The concentrated sludge in the mesh tray 11 is dropped into the sludge storage tank 4 by the impact when the tip of the window frame 9 contacts the rack 15.

When the elevator conveyor device 3 is driven, the excess sludge, which has been gradually increased in the activated sludge treatment tank 1, is scooped up on the mesh tray 11, and the activated sludge treatment tank 1
In the process of scooping, the excess sludge that has been scooped is transported upward while draining. During the ascending transport, the mesh tray 11 vibrates every time the window frame 9 of the mesh tray 11 comes into contact with the rack 13 of the vibrating member 12, and the draining and dewatering effect of the excess sludge scooped up is promoted.

As a result, concentrated sludge remains on the mesh tray 11, and when the mesh tray 11 is inverted at the rising end of the elevator conveyor device 3, the concentrated sludge on the mesh tray 11 is dropped into the sludge storage tank 4. When the mesh tray 11 is turned over, the window frame 3 is moved by the impact member 1.
The impact is given when it comes into contact with the rack 15 of No. 4, and the concentrated sludge is quickly removed from the mesh tray 11.
By repeating the above operation, the drained and dewatered concentrated sludge is efficiently stored in the sludge storage tank 4.

In the above case, the secondary treatment device for sewage treatment is as follows:
The sludge concentration method of surplus sludge and its apparatus in the case of an activated sludge treatment tank were explained.However, when the target of sewage treatment was livestock wastewater such as pig sewage wastewater, it was deposited at the stage of the primary treatment equipment. It can also be used as a means for eliminating an increase in the primary treatment load due to an increase in the amount of sludge. In short, the sludge collected in the primary treatment tank and the increased amount of sludge that is being stirred in the tank are scooped up as excess sludge by the mesh tray of this equipment, drained, and stored in the sludge storage tank to reduce the primary processing load. You can also. This is the same in other embodiments of the sludge concentrator described below.

In the above case, the vibration member 12 is formed so as to be in contact with the window frame 9 of the mesh tray 11.
A vibration conveyor that mechanically applies vibration to the belt conveyor 5 itself by an electromagnet, a vibration motor, or the like may be adopted.

[0022]

[Modification] In the above case, the case where the mesh tray 11 is provided on the belt conveyor 5 has been described.
The elevator conveyor device 3 may be constituted by a chain conveyor (not shown), and the mesh tray 11 as described above may be attached to the chain conveyor to cope with sludge concentration.

[0023]

Second Embodiment In the case of the elevator conveyor device 3 shown in FIG. 3, the conveyor belt is formed by a mesh conveyor 16 and the excess sludge of the activated sludge treatment tank 1 is scooped by the mesh conveyor 16. A tray 17 (a mesh tray is also acceptable) in the form of a flat U-shaped frame is attached. Such a mesh conveyor 16 and a tray 17
Thereby, it is possible to cope with draining of excess sludge scooped up from the activated sludge treatment tank 1 and dropping of concentrated sludge into the sludge storage tank 4.

[0024]

Third Embodiment In the case of the elevator conveyor device 3 shown in FIGS. 1 and 3 described above, one of them is immersed in the activated sludge treatment tank 1 and the other is placed in the upper part of the sludge storage tank 4. , The elevator conveyor device 3 is supported almost vertically in the activated sludge treatment tank 1 as in the case of the third embodiment shown in FIG.
The concentrated sludge from the mesh tray 11 that reaches the rising end and turns over may be dropped into the sludge storage tank 4 via the discharge chute 18.

[0025]

Fourth Embodiment Next, in the case of a fourth embodiment shown in FIG. 5, the mesh tray 11 is mounted on a rotary water turbine 19 driven by a motor. The sludge is drained by slowly scooping it up and draining the sludge. When the mesh tray 11 reaches the vicinity of the upper end, the concentrated sludge is dropped from the discharge chute 18 into the sludge storage tank 4.

[0026]

Fifth Embodiment In the case of a fifth embodiment shown in FIG. 6, a mesh tray 11 is formed at the distal end of a swing arm 20 driven by a motor. The part can rotate forward and reverse, and
A slow-moving positive cam (not shown) is provided, and the positive cam is driven by a motor so that excess sludge in the activated sludge treatment tank 1 is slowly lifted up while being scooped up, thereby draining the mesh. The concentrated sludge is put into the sludge storage tank 4 by rapidly rotating the swing arm 20 at the time when reaches the vicinity of the upper end.

[0027]

As described above, the present invention scoops out excess sludge from the treatment tank and removes the excess sludge from the treatment tank in the process of lifting it out of the treatment tank, and throws the remaining concentrated sludge into the sludge storage tank. The sludge concentrating method and its apparatus are made as described above, and as before, excess sludge is once pumped into a sludge concentrating storage tank and then separated into solids and liquids. In addition to eliminating the uneconomical sludge concentration method of returning the desorbed liquid for reprocessing, the sludge concentration for excess sludge that is gradually increased in the secondary treatment stage of sewage treatment and the primary treatment stage Efficiency and its collection efficiency are dramatically improved.

Further, the treatment load accompanying the increase in the amount of excess sludge in the secondary treatment stage and the primary treatment stage of the sewage treatment is remarkably reduced, and various effects such as significantly increasing the sewage treatment efficiency in each of these stages are obtained. Bring.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a sludge concentration device.

FIG. 2 is an enlarged view of a main part showing a mesh tray attached to a belt conveyor, where (A) is a side view and (B) is a perspective view.

FIG. 3 is a perspective view showing a case where a belt conveyor is a mesh conveyor.

FIG. 4 is a diagram illustrating a third embodiment in which the elevator conveyor device is vertically set up in a processing tank.

FIG. 5 is a view showing a fourth embodiment in which a mesh tray is attached to a rotary water turbine.

FIG. 6 is a view showing a fifth embodiment in which a mesh tray is attached to the tip of a swing arm.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 activated sludge treatment tank 2 diffuser pipe 3 elevator conveyor device 4 sludge storage tank 5 conveyor belt 6 drive roller 7 driven roller 8 support girder 9 window frame 10 mesh 11 mesh tray 12 vibrating member 13, 15 rack 14 impact member 16 mesh conveyor 17 Tray 18 Discharge chute 19 Rotary water turbine 20 Swing arm

Claims (11)

[Claims] 1. A method for concentrating sludge comprising scooping out excess sludge from a treatment tank, draining the excess sludge scooped up in the process of lifting the sludge from the treatment tank, and charging the remaining concentrated sludge into a sludge storage tank. 2. A process of scooping up excess sludge in a treatment tank using a mesh tray, and in a process of scooping it out of the treatment tank, draining the excess sludge that has been scooped out and putting concentrated sludge remaining in the mesh tray into a sludge storage tank. Sludge concentration method. 3. The sludge concentration method according to claim 2, wherein a mesh tray is vibrated when draining excess sludge. 4. When the concentrated sludge is charged into a sludge storage tank,
The sludge concentration method according to claim 2, wherein an impact is applied to the mesh tray. 5. A mesh tray for immersing and supporting one of the elevator conveyor devices in the sludge of the treatment tank and the other facing the upper part of the sludge storage tank, and attaching the excess tray to the elevator conveyor device. Sludge concentrator. 6. An elevator conveyor device, one of which is immersed and supported in the sludge of the treatment tank, and the other of which faces the upper part of the sludge storage tank, wherein the conveyor belt of the elevator conveyor device is a mesh conveyor. A sludge concentrator equipped with a tray or mesh tray for scooping up excess sludge on a conveyor. 7. An elevator conveyor device is supported substantially vertically in sludge in a treatment tank, a mesh tray for scooping up excess sludge is attached to the elevator conveyor device, and a discharge chute to a sludge storage tank is provided above the elevator. A sludge concentrating apparatus, wherein concentrated sludge from a mesh tray that reaches a rising end of an elevator conveyor device and turns over is dropped into a sludge storage tank via a discharge chute. 8. A treatment tank is immersed in a rotary turbine driven by a motor, a mesh tray is attached to the rotary turbine, and a discharge chute to a sludge storage tank is provided on an upper portion of the mesh turbine. The concentrated sludge remaining on the mesh tray is dropped from the discharge chute into the sludge storage tank when the mesh tray reaches the vicinity of the upper end of the rotary turbine. Sludge concentrator. 9. A mesh tray is formed at a distal end of a swing arm driven by a motor, and the base end of the swing arm is driven by a motor, so that excess sludge in the treatment tank is lifted up while being scooped by the mesh tray. A sludge concentrating apparatus characterized in that the sludge is concentrated by throwing the sludge into a sludge storage tank by rapidly rotating the swing arm when the mesh tray reaches the vicinity of the upper end of the swing arm. 10. A means for applying vibration to a mesh tray or a conveyor belt.
The sludge concentrator according to claim 7, claim 8, or claim 9. 11. The sludge concentrator according to claim 5, further comprising means for imparting an impact to the mesh tray or the tray.