JPH0852487A - Method for adding and mixing magnetic powder and device therefor - Google Patents

Abstract

PURPOSE:To uniformly disperese and stick magnetic powder to into an activated sludge in an aeration tank and to improve magnetic separating characteristic in a magnetic separating device for post-treatment. CONSTITUTION:In this method for adding and mixing magnetic powder P in the aeration tank 17 in order to separate the activated sludge liq. A into the activated sludge and a treated water by transferring the activated sludge liq. A in the aeration tank 17 to the magnetic separating device 18 for post- treatment, the magnetic powder P and water W are mixed and stirred, them the mixture is added and mixed with the activated sludge liq. A in the aeration tank 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adding and mixing magnetic powder in an activated sludge liquid in order to separate the activated sludge liquid in an aeration tank into activated sludge and treated water in a post-treatment magnetic separator. The present invention also relates to an apparatus and a device therefor, in particular, a method for adding and mixing magnetic powder that can uniformly disperse and attach magnetic powder to activated sludge.

[0002]

In the treatment of sewage, an activated sludge method in which sewage is reacted with microorganisms to decompose organically is widely known. In order to separate the activated sludge liquid into activated sludge and treated water,
The activated sludge in the activated sludge active solution is allowed to sink naturally and only the supernatant treated solution is discharged to the post-treatment side. In recent years
As disclosed in Japanese Patent Publication No. 48-42570, there is also a proposal to improve the solid-liquid separation of activated sludge by aggregating the activated sludge by adding magnetic powder to the activated sludge and mixing it with a magnetic field. Has been done.

Furthermore, Japanese Patent Publication No. 63-59759 proposes to improve the solid-liquid separation of activated sludge liquid by adsorbing activated sludge containing magnetic powder with a magnet. In this proposal, as shown in FIG. 5, a separation tank 4 is installed in a transfer system 3 for transferring activated sludge liquid A from an aeration tank 1 via a pump 2, and a rotary magnet 5 rotating in the separation tank 4 is installed. Activated sludge B which adsorbs activated sludge B and activated sludge liquid A contains magnetic powder
And treated water C can be continuously separated. Part of the separated activated sludge B is returned to the aeration tank 1 in order to keep the concentration of the activated sludge B constant, and only the treated water C is discharged from the separation tank 4.

[0004]

By the way, in such a magnetic separation sludge method, the magnetic separation characteristics of the post-treatment are determined by whether or not the adhesion of the magnetic powder to the activated sludge is uniform, and the magnetic powder is made uniform. In order to disperse the magnetic powder onto the activated sludge B and attach it to the activated sludge B, it is effective to reduce the particle diameter of the magnetic powder from several tens μm to several μm or less.

On the other hand, as shown in FIG. 6, when the magnetic powder P is miniaturized into fine particles, the fine particles before being added and mixed in the aeration tank 1 attract each other due to a magnetic force or the like and strongly agglomerate to several tens of μm. Secondary particles Q having a size of several 100 μm are formed. Therefore, as shown in FIG. 7, the magnetic powder P may adhere to the activated sludge B as a lump. Mechanical agitation in the aeration tank may be considered, but this may destroy microorganisms. Therefore, in the post-treatment magnetic separation device, the behavior of the activated sludge in the magnetic field space becomes non-uniform,
There is a problem that sufficient magnetic separation characteristics cannot be obtained.

The present invention was devised to effectively solve the above problems. INDUSTRIAL APPLICABILITY The present invention makes it possible to uniformly disperse and adhere magnetic powder to activated sludge in an aeration tank, and to improve the magnetic separation characteristics in a magnetic separation apparatus for post-treatment, and a method for adding and mixing magnetic powder and the apparatus. The purpose is to provide.

[0007]

According to the present invention, in order to transfer the activated sludge liquid in the aeration tank to a magnetic separator for post-treatment and separate the activated sludge liquid into activated sludge and treated water, the aeration tank is provided. In the method for adding and mixing the magnetic powder, the magnetic powder is mixed with water and stirred, and then mixed with the activated sludge liquid in the aeration tank.

In the present invention, magnetic powder is added to the aeration tank in order to transfer the activated sludge liquid in the aeration tank to a post-treatment magnetic separation device to separate the activated sludge liquid into activated sludge and treated water. In the device for mixing, a transfer path for mixing and transferring the magnetic powder with water is formed in the aeration tank, and a stirrer is provided in the middle of the transfer path.

[0009]

In the above structure, the magnetic powder is mixed with water to be fluidized and stirred so that the magnetic powder is uniformly dispersed and adhered to the activated sludge.

Further, the magnetic powder is uniformly dispersed and adhered to the activated sludge by a simple structure in which a stirrer is installed in a passage for mixing and transferring the magnetic powder with water.

[0011]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 4 shows an example of the sewage treatment process. This sewage treatment process 11 is mainly a water treatment system 12.
And sludge treatment system 13.

In the water treatment system 12, the sewage pumped by the pump 14 passes through the sand basin 15, the first settling basin 16, the aeration tank (aeration tank) 17 and the magnetic separation device 18, and then passes through the tertiary treatment facility 19 to be reprocessed. It is used or discharged through the sterilization tank 21. In the aeration tank 17, aeration blower 22 is connected in order to react sludge water with microorganisms for organic decomposition and further promote the reaction decomposition. Further, magnetic powder is added and mixed into the aeration tank 17 in order to facilitate solid-liquid separation of the activated sludge liquid A.

First, the sludge discharged from the settling tank 16 and the magnetic separator 18 through the pump 23 is the sludge treatment system 13.
In order to treat the sludge, the sludge treatment system 13 includes a sludge concentrator 24, a sludge centrifugal concentrator 25, and a sludge fire tank 2.
6, a gas holder 27, a belt press 28, a centrifugal dehydrator 29, and a sludge incinerator 31 are installed.

Particularly, in order to add and mix the magnetic powder P into the aeration tank 17, a transfer path 41 for connecting the magnetic powder P with water W from above is connected into the aeration tank 17 as shown in FIG.
In the middle of the transfer path 41, a stirring tank 42 is provided beside the aeration tank 17 and is provided. A stirrer 44 including a propeller 43 is installed in the stirring tank 42.

Next, a method of adding and mixing magnetic powder will be described.

Even if the magnetic powder P, which has been made finer than several μm, aggregates to form secondary particles of several tens of μm to several hundreds of μm, the magnetic powder P is mixed with the water W and transferred along the transfer path 41. Is
It is temporarily stored in a stirring tank 42 provided in the middle of the transfer path 41. The magnetic powder P mixed and fluidized with the water W is agitated by the agitator 44 rotating in the agitation tank 42. By stirring with the stirrer 44, the secondary particles are decomposed to have an original particle size of several μm or less and uniformly dispersed in the water W as shown in FIG.

Since the magnetic powder P is added and mixed into the aeration tank 17 while being kept in a uniformly dispersed state, the magnetic powder P should be attached to the activated sludge D substantially uniformly as shown in FIG. You can Therefore, in the post-treatment magnetic separation device 18, the behavior of the activated sludge D in the magnetic field space is made uniform, and the magnetic separation characteristics can be improved.

[0019]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) In claim 1, since the magnetic powder is mixed with water and stirred, and then added and mixed into the aeration tank, the magnetic powder can be uniformly dispersed and adhered to the activated sludge, Magnetic separation characteristics can be improved.

(2) In claim 2, the magnetic powder can be uniformly dispersed and attached to the activated sludge with a simple structure in which a stirrer is installed in a passage for mixing and transferring the magnetic powder with water. .

[Brief description of drawings]

FIG. 1 is a front view showing an apparatus for adding and mixing magnetic powder according to the present invention.

FIG. 2 is a diagram showing magnetic powder before being added and mixed in the aeration tank.

FIG. 3 is a diagram showing a state in which magnetic powder is attached to activated sludge.

FIG. 4 is a diagram showing an example of a sewage treatment process.

FIG. 5 is a front view showing a conventional magnetic separation device.

FIG. 6 is a view showing a conventional magnetic powder before being added and mixed in the aeration tank.

FIG. 7 is a view showing a conventional example in which magnetic powder is attached to activated sludge.

[Explanation of symbols]

 17 Aeration Tank 18 Magnetic Separation Device 41 Transfer Path 44 Stirrer A Activated Sludge Liquid B Activated Sludge C Treated Water P Magnetic Powder

Claims (2)

[Claims] 1. To add and mix magnetic powder in the aeration tank in order to transfer the activated sludge liquid in the aeration tank to a magnetic separator for post-treatment to separate the activated sludge liquid into activated sludge and treated water. In the above method, the magnetic powder is mixed with water and stirred, and then mixed with the activated sludge liquid in the aeration tank. 2. To add and mix magnetic powder in the aeration tank in order to transfer the activated sludge liquid in the aeration tank to a magnetic separator for post-treatment to separate the activated sludge liquid into activated sludge and treated water. 2. The apparatus for adding and mixing magnetic powder according to claim 1, wherein a transfer path for mixing and transferring the magnetic powder with water is formed in the aeration tank, and a stirrer is provided in the transfer path.