JPH06142690A - Purifying device for sewage of intermittent aeration type - Google Patents

Abstract

PURPOSE:To improve the utilization efficiency and the sludge feeding-back efficiency, respectively of an air blower by switching the air blower of an aeration layer ratio to each speed of revolution being suitable for a simultaneous operation of an aeration device of an aeration tank and a sludge feeding-back air lift of a sedimenting tank, and an operation of only the air lift, respectively. CONSTITUTION:In the sewage purifying device B of an intermittent aeration type, an aeration tank 2 into which sewage is allowed to flow from an inflow tube 1 is provided with an aeration device 3 consisting of an air blower 30 for force-feeding air, a feed air tube 31 and a diffusing tube 32. In this case, the air blower 30 is used in common as an air blower for operating an air lift 6 for feeding back sludge, provided in a sedimenting tank 4. Also, to the feed air tube 31, a control valve V is connected. Moreover, a driving motor M of the air blower 30 is constituted so that is rotating speed is variable, and also this rotating speed is interlocked with an opening/closing operation of the control valve V and controlled by a control panel 7. Furthermore, the air blower 30 is controlled so as to be switched to the speed of revolution being suitable for a simultaneous operation of the aeration device 3 and the air lift 6, and the speed of revolution being suitable for an operation of only the air lift 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for purifying sewage using an activated sludge method, which aerates sewage containing organic substances such as domestic wastewater and industrial effluent in an aeration tank to grow activated sludge for treatment. , Intermittent aeration type sewage purification device that performs denitrification operation in the non-aeration anaerobic state process between the aeration process and the aeration process by intermittently operating the aeration device provided in the aeration tank Regarding the improvement of.

[0002]

2. Description of the Related Art The purification treatment of wastewater containing organic substances is usually
It is carried out by the treatment means by the activated sludge method. This sewage treatment means puts sewage in an aeration tank, and aerates it with an aeration device to grow activated sludge, so that BOD, C
It is a means of removing OD, exhibits excellent performance, and has many installation records.

[0003] Further, in the purification treatment means for wastewater by the activated sludge method, the aeration apparatus has been operated continuously so that the aeration operation is continuous, but the aeration operation is performed intermittently. In the non-aerated anaerobic state process between the aeration process and the aeration process, nitrogen contained in the wastewater is released as nitrogen gas, and denitrification of about 50 to 90% can be obtained. I understand.

From this, as shown in FIG. 1, the aeration tank 2 for receiving the sewage fed from the inflow pipe 1,
An aerator 3 including an air blower 30 such as a compressor or a blower that sends air under pressure, an air feed pipe 31, an air diffusing pipe 32, and the like is assembled, and sewage is grown into activated sludge by the aeration by the operation of the aeration device 3 to purify it. An air lift 6 is sent to the settling tank 4, where the supernatant liquid is taken out by the outflow pipe 5, and the sludge settling at the bottom of the settling tank 4 is returned to the front end of the inside of the aeration tank 2. An air supply pipe 31 communicating with the discharge port of the blower 30 via a branch pipe is connected to this, and the air lift 6 sucks up the sludge settling at the bottom of the settling tank 4 and places it in the aeration tank 2. A means for intermittently performing aeration operation in the aeration tank 2 is added to the sewage water purification apparatus A by the activated sludge method configured to be returned, and an intermittent aeration type sewage water purification apparatus is provided. Tosu Attempts have been made.

[0005]

It is, for example, possible to intermittently perform the aeration operation of the aeration tank 2 of the apparatus A for purifying sewage by the conventional activated sludge method, which is constructed as described above. This can be performed relatively easily by separately providing a blower 30 of the aeration device 3 and a blower for an air lift connected to the air lift 6, and making the blower 30 of the aeration device 3 operate intermittently. .

However, the blower 30 of the aeration device 3 incorporated in the sewage purification device A has a sufficient ability to be commonly used by both the aeration device 3 and the air lift 6, and is usually the one shown in FIG. As shown in FIG. 3, the branch pipe is connected to the air feed pipe 60 for the air lift 6 and the air feed pipe 31 for the aeration device 3 so that the blower 30 is shared. Incorporating a blower into each of the air blower 60 and the air feed pipe 60 of the air lift 6 causes a problem that the efficiency of use of the blower is deteriorated and the facility cost is increased.

Further, as shown in FIG. 1, the blower 30
Is used for both the aeration device 3 and the air lift 6, and the blower 30 is provided with a control valve V that can be opened and closed as desired in the air supply pipe 31 for the aeration device 3.
By continuously opening and closing the control valve V at a desired interval while continuously operating the aeration tank 2, the aeration operation in the aeration tank 2 is performed intermittently. When the aeration operation in the aeration tank 2 is set to a non-aeration process by closing the valve, all of the compressed air discharged from the blower 30 is blown into the air lift 6 to configure the sludge return pipe. The action of the air lift 6 becomes excessive, and the sludge returned from the settling tank 4 becomes excessively larger than the predetermined amount with respect to the waste water in the aeration tank 2 that has been transferred to the non-aeration process, which causes a problem. Come out.

[0008]

[Purpose] The present invention has been made to solve these problems, and is for a blower 30 for aeration of sewage in the aeration tank 2 and for an air lift that returns sludge settling in the settling tank 4. While making it a shared form with the blower of
When the aeration of sludge in the aeration tank 2 is stopped and the air is not aerated, the operation of the air lift 6 is adapted to the return of the sludge to improve the utilization efficiency of the air blower. It is an object of the present invention to provide a new means capable of constituting an intermittent aeration type wastewater purification device in which sludge is appropriately returned by a lift.

[0009]

In the present invention, as means for achieving the above object, an air blower for returning sludge, which is provided in a settling tank, is equipped with a blower of an aeration device provided in the aeration tank. The control valve is connected to the air pipe of the aerator, the drive motor of the blower is a motor whose rotation speed can be changed, and the rotation speed of the motor is controlled by the control circuit provided on the control panel. By interlocking with the operation of opening and closing, the blower is switched between the rotational speed that is the ability to adapt to the simultaneous operation of both the aerator and the air lift, and the rotational speed that is the capacity to adapt to the operation of the air lift only. It proposes an intermittent aeration type sewage purification device that is controlled as described above.

[0010]

Embodiments Next, embodiments will be described in detail with reference to the drawings. The same reference numerals are used for the constituent members having the same effects as those of the conventional means.

FIG. 2 is a developed longitudinal sectional view of an intermittent aeration type sewage purification apparatus B according to the present invention. In FIG.
Is an inflow pipe for guiding sewage, 2 is an aeration tank, 3 is an aerator consisting of a blower 30 for discharging compressed air such as a compressor or a compressed air blower, an air supply pipe 31 and an air diffuser pipe 32 for blowing out air, and 4 is an aeration tank 2 A settling tank for receiving the sewage treated in step 1 and separating it into sludge and supernatant water, 5 is an outflow pipe for discharging the supernatant water from the precipitation tank 4, and 6 is an aeration tank 2 for sludge settling at the bottom of the precipitation tank 4. An air lift which serves as a sludge return pipe for returning to the front end of the inside, 60 is an air blower for blowing compressed air to operate the air lift 6, and V is an aeration device 3
Is a control valve provided in the air supply pipe 31 of M, a drive motor M drives the blower 30 of the aeration device 3, and a control panel 7 controls the operation of the drive motor M and the control valve V.

Aeration tank 2, aeration device 3 and precipitation tank 4
In addition, the air lift 6 etc. are the conventional wastewater purification device A
It is no different from that of Then, in order for the air lift 6 serving as a sludge return pipe to suck up the sludge settling at the bottom of the settling tank 4 and return it to the aeration tank 2, compressed air is blown into the air lift 6. The base end side of the air supply pipe 60 connected in this way is connected and communicated with the discharge port of the compressed air of the blower 30 of the aeration device 3 through a branch pipe, and thereby the air blower 30 for the aeration device 3 is connected. It is configured to be shared by the blower for the air lift 6. Further, the aeration process of the sludge in the aeration tank 2 is performed by intermittent aeration by alternately repeating the aeration process and the non-aeration process, and the control is performed such that the aeration pipe 31 of the aeration device 3 is operated.
By controlling the opening and closing of the control valve V provided in the
The communication of the discharge port of the blower 30 to the air diffuser 32 is controlled by on / off control.

As the drive motor M for driving the blower 30 of the aeration device 3, an inverter motor or the like for controlling the change of the rotation speed is used. The rotation speed of the control valve V is linked to the operation of opening and closing the control valve V connected to the air supply pipe 31 of the aeration device 3 by the control circuit provided in the control panel 7, and the control valve V is opened. When the air blower 30 is operated, the blower 30 has a rotation speed that is an ability to adapt to the simultaneous operation of both the aeration device 3 and the air lift 6, and when the control valve V is closed, the blower 30 is It is controlled so that the number of rotations is such that it has an ability to adapt to actuating only the air lift 6.

70 and 71 are control valves V and blowers 30.
This is wiring for connecting the control valve V and the drive motor M to the control panel 7 in order to control the operation of the drive motor M of FIG.

[0015]

As described above, the intermittent aeration type sewage purification apparatus according to the present invention aerates the blower 30 for the aeration device 3 for aerating the sewage in the aeration tank 2 and the sludge settling in the settling tank 4. The air blower for the air lift 6 returning to the tank 2 is also used in common, and the control valve V provided connected to the air feed pipe 31 of the aeration device 3 is controlled to be opened and closed to alternately repeat the aeration process and the non-aeration process. Thus, when intermittent aeration is performed, the drive motor M that drives the blower 30 is a motor that can change the rotation speed of an inverter motor or the like, and is linked to the operation that controls the opening and closing of the control valve V. Thus, the blower 30 is switched to a rotation speed that is adapted to simultaneously operate both the aeration device 3 and the air lift 6 to a rotation speed that is adapted to only operate the air lift 6. Therefore, the air blower 30 for aeration of the sewage in the aeration tank 2 and the air lift blower for returning the sludge settling in the settling tank 4 are commonly used, while the aeration tank is used in common. When the aeration of the sludge in 2 is stopped and the air is not aerated, the air lift 6
The operation of is adapted to the return of sludge, and the intermittent aeration type sewage purification device can be obtained in which the sludge is appropriately returned by the air lift while improving the utilization efficiency of the blower. Like

[Brief description of drawings]

FIG. 1 is a longitudinal sectional side view of a conventional sewage purification device using an activated sludge method.

FIG. 2 is a longitudinal side view of the intermittent aeration type sewage purification device by the activated sludge method according to the present invention.

[Explanation of symbols]

A: Sewage purification device by activated sludge method, B: Intermittent aeration type purification device, V ... Control valve, M ... Drive motor, 1
... inflow pipe, 2 ... aeration tank, 3 ... aeration device, 30 ... blower,
31 ... Air supply pipe, 32 ... Air diffusion pipe, 4 ... Precipitation tank, 5 ... Outflow pipe, 6 ... Air lift, 60 ... Air transmission pipe, 7 ... Control panel, 7
0.71 ... Wiring.

Claims (1)

[Claims] 1. The air blower 30 of the aeration device 3 installed in the aeration tank 2 is also used as a blower for operating the air lift 6 for returning sludge, which is installed in the settling tank 4, and the air supply pipe 31 of the aeration device 3 is used.
Is connected to the control valve V, the drive motor M of the blower 30 is a motor whose rotational speed is changeable, and its rotational speed is
The number of revolutions that makes the blower 30 capable of adapting to the simultaneous operation of both the aeration device 3 and the air lift 6 by interlocking with the operation of opening and closing the control valve V by the control circuit provided in the control panel 7, and the air lift. An intermittent aeration type sewage purification device that is controlled so as to switch to a rotation speed that has the ability to adapt to only 6 operations.