JP3043092B2 - Operating method of activated sludge treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating an activated sludge treatment apparatus capable of easily switching to an aerobic operation or a combination of an aerobic operation and an anaerobic operation as required in an activated sludge treatment method.

[0002]

2. Description of the Related Art Generally, activated sludge treatment of wastewater is performed by providing a plurality of aeration tanks and blowing air or oxygen-enriched gas into each aeration tank, or a plurality of aeration tanks having a cover as shown in FIG. The liquid-phase part 2 and the gas-phase part 3 of the aeration device 1 (aeration tanks 1a, 1b, 1c, 1d from the first to the fourth in FIG. 5) are connected by communication holes 2a and 3a, respectively. Then, the wastewater 4 to be treated and the oxygen-enriched gas or air (hereinafter referred to as oxygen) 5 are flowed from the tanks 1a to 1d, and the lower stirring blades 6a for stirring the liquid phase portion 2 are provided.
In addition, the upper stage agitating blades 6b that agitate and aerate the boundary between the liquid phase portion 2 and the gas phase portion 3 are agitated by a stirrer 6 fixed to a rotating shaft 6c at intervals to perform aerobic operation in all stages. .
7 is a settling tank for sludge, 8 is returned sludge, and 10 is exhaust gas.

However, the quality of wastewater to be treated fluctuates depending on the season, and it is necessary to comply with the regulations of P and / or N. In addition, in the summer season, a bulking phenomenon occurs, making it difficult for activated sludge to settle. In some cases, driving became difficult.

Conventionally, as a countermeasure against these problems, a part of the aeration apparatus 1 needs to be operated anaerobically, so that the anaerobic operation has been performed by setting a submersible pump or replacing the stirrer 6.

[0005]

By the way, in wastewater treatment facilities such as an urban sewage treatment plant, setting the above-mentioned submersible pump or replacing the stirrer requires time and a large number of manual operations to switch the anaerobic operation. This is a laborious and laborious task.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an operation method of an activated sludge treatment apparatus capable of easily switching to either anaerobic operation or aerobic operation as a whole in a short time. The purpose is to provide.

[0007]

In the method for operating an activated sludge treatment apparatus according to the present invention, a plurality of aeration tanks provided with a sealing lid are arranged in series, and the gas phase part and the liquid phase of these aeration tanks are arranged. The parts communicate with each other along the direction in which the fluid flows, and the oxygen-enriched gas or air flows through the gas phase, the liquid to be treated flows through the liquid phase, and the aeration tanks flow into each aeration tank. Activated sludge treatment equipment equipped with a stirrer having two stages of stirring blades attached to the same rotating shaft at intervals, the lower stage stirring blades agitate the liquid phase, and the upper stage stirring blades agitate and aerate the gas-liquid boundary. In the driving method of

The rotating shaft of at least one stirrer is vertically movable, and during anaerobic operation, the rotating shaft is moved upward so that the lower stirring blade is positioned in the liquid phase and the upper stirring blade is moved. It was a means of solving the problem by being located in the gas phase.

[0009]

Since the method of operating the activated sludge treatment apparatus of the present invention has the above-described configuration, the operation of the anaerobic and aerobic combined operation or the aerobic operation can be performed by operating the stirrer whose rotary shaft can be moved up and down. You can switch to either.

[0010]

FIG. 1 shows the first (first stage) for removing P.
This embodiment shows the first embodiment of the present invention in which the aeration tank can be switched between aerobic operation and anaerobic operation. The same parts as those in FIG.

In the tank 1a, the rotating shaft 6c can be moved up and down. By moving the rotating shaft 6c up and down, the lower stirring blade 6a is positioned in the liquid phase portion 2 and the upper stirring blade 6b is moved.
Are located in the gas phase part 3. In the P removal, most of the sludge that has settled and concentrated in the settling tank 7 is returned to the anaerobic tank 1a as returned sludge, as in the case of the entire aerobic operation. The oxygen 5 is introduced into the second tank 1b which is kept aerobic and flows downstream.

The mechanism for vertically moving the rotary shaft 6c is, for example, the one shown in FIG. That is, the rotating shaft 6
c is rotatably supported by a shaft support 21 and is rotationally driven by a motor 23 via a speed reducer 22. A level indicator 24 is provided above the support 21,
A shaft lifting jack 25 is provided on the upper part. This jack 25 is connected to an upper miter gear box 27 via a chain coupling 26. A lower miter gear box 28 is fixed to a lower portion of the support 21. These upper and lower miter gear boxes 27, 2
8, a connecting shaft 29 is disposed via upper and lower chain couplings 30, 31, respectively. A handle 32 is attached to the miter gear box. By rotating the handle, the jack 25 rotates and the rotating shaft 6c moves up and down.

As described above, in order to make the aeration tank anaerobic for P removal, the handle 32 is rotated to move the rotating shaft 6c of the first tank 1a upward, and the introduction of oxygen 5 is performed second. Should be switched to the tank 1b. In this case, the gas phase portion 3 of the tank 1a is communicated with the communication hole 3a through the communication hole 3a, but the oxygen gas flows downstream from the tank 1b, and the upper stirring blade 6b rotates in the gas phase portion 3 and Since the boundary is not stirred, the tank 1a is kept anaerobic.

When the operation for removing N is performed, FIG.
As shown in the above, while rotating the rotating shaft 6c of the tank 1a upward, oxygen 5 is introduced into the tank 1b, and a part of the liquid in the final tank 1d may be circulated to the tank 1a as the circulating nitrification liquid 9. Also in this case, the gas phase portions 3 of the tanks 1a and 1b are communicated with each other by the communication holes 3a, but the oxygen 5
The tank 1a is kept anaerobic because it flows to c and 1d.

FIG. 3 shows a case in which P and N are removed, and the rotation axes of the tanks 1a and 1b are movable in the vertical direction. In this case, the oxygen 5 is introduced into the third tank 1c, and the nitrification liquid in the fourth tank 1d is circulated to the tank 1b. The holes 1a, 1b, 1c, and 1d are similarly connected by the hole 3a. However, since the oxygen gas flows downstream from the tank 1c, the tank 1b is kept anaerobic, and the tank 1a is further anaerobic. Will be retained.

FIG. 4 shows still another embodiment.
This shows a case where one intermediate tank, for example, the tank 1b is made anaerobic. In this case, the rotating shaft 6c of the tank 1b is moved upward to be anaerobic. In this case, oxygen is flowed from the tank 1a to the tank 1d. Therefore, oxygen gas also flows into the tank 1b, but the upper stirring blade 6b is located in the gas phase, and the gas-liquid boundary is not stirred. Therefore, oxygen gas is
When flowing from tanks 1a to 1d, it passes through the gas phase of tank 1b,
Since the upper stirring blade 6b is located in the gas phase part 3, the gas-liquid boundary is not stirred and the anaerobic property is maintained.

As described above, the rotating shaft of the agitator of the aeration tank which needs to be switched between anaerobic and aerobic can be moved up and down, whereby the upper stirring blade is located at the gas-liquid boundary and in the gas phase, If the wing is always located in the liquid phase, it can be used for almost all types of operation of the aerator.

[0018]

Example 1 A closed-stage activated sludge treatment apparatus consisting of three stages without 1d among the four stages of aeration tanks shown in FIG. 1 was used, and the whole was subjected to aerobic operation through an oxygen-enriched gas, and the first stage. Was subjected to wastewater treatment when anaerobic operation was performed. In the tank in which the anaerobic operation is performed, the required power is small because the upper stage impeller is in the gas phase section 3. Table 1 shows the wastewater used and the wastewater treatment results.

[0019]

[Table 1]

[0020]

As described above, in the method for operating the activated sludge treatment apparatus according to the present invention, the rotating shaft of the stirrer can be moved in the vertical direction, and the lower stage, which is always located in the liquid, is spaced from the rotating shaft. Since the stirring blade and the upper stirring blade which can be positioned in the gas phase or at the gas-liquid boundary are provided, the aeration tank can be easily switched to the aerobic operation or the anaerobic operation, and furthermore, the oxygen is further reduced. Since the selection of the aeration tank to be introduced is performed by operating the valve and circulating the nitrification liquid by operating the valve and starting the pump, it is easy to use various operation modes such as P removal, N removal, P and N removal, and bulking removal. There is an advantage that can be handled.

[Brief description of the drawings]

FIG. 1 is a diagram of an aeration apparatus in which a first aeration tank is operated under anaerobic operation.

FIG. 2 is a schematic view of a stirrer driving portion capable of moving a rotating shaft up and down.

FIG. 3 is a diagram of an aeration apparatus in which first and second aeration tanks are operated anaerobically.

FIG. 4 is a diagram of an aeration apparatus in which a second aeration tank is anaerobically operated.

FIG. 5 is a diagram of an aeration apparatus in which all aeration tanks are operated aerobically.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aeration apparatus 1a 1st aeration tank 1b 2nd aeration tank 1c 3rd aeration tank 1d 4th aeration tank 2 Liquid phase part 2a Liquid phase communication hole 3 Gas phase part 3a Gas phase communication hole 4 Treated wastewater ( (Wastewater) 5 Oxygen-enriched gas or air (oxygen) 6 Stirrer 6a Lower stirring blade 6b Upper stirring blade 6c Rotary shaft 7 Settling tank 8 Returned sludge 9 Circulating nitrification liquid 10 Exhaust

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Claims (3)

(57) [Claims] A plurality of aeration tanks provided with a sealing cover are arranged in series, and the gas phase part and the liquid phase part of these aeration tanks are communicated with each other along the direction in which a fluid flows. Stirrer with oxygen-enriched gas or air flowing in the section, liquid to be treated flowing in the liquid phase section, and two agitating blades attached to each aeration tank at the same rotation axis at intervals In the operating method of the activated sludge treatment apparatus in which the lower stirring blade stirs the liquid phase portion and the upper stirring blade stirs and aerates the gas-liquid boundary, the rotating shaft of at least one stirrer moves vertically. Activated sludge treatment apparatus characterized in that the rotating shaft is moved upward during anaerobic operation and the upper stirring blade is positioned in the gas phase while the lower stirring blade is positioned in the liquid phase. Driving method. 2. The method for operating an activated sludge treatment apparatus according to claim 1, wherein an aeration tank provided with a stirrer whose rotary shaft is movable in a vertical direction is provided at a first stage of the plurality of aeration tanks. Wherein oxygen-enriched gas or air, operating method of claim 2 activated sludge treatment apparatus according to the rotation shaft does not move in the vertical direction is flowed to the aeration tank provided with a stirrer attached.