JP3426455B2 - Operating method of sewage 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 a sewage treatment apparatus, and more particularly to an operation method for a sewage treatment apparatus for treating irregularly flowing sewage.

[0002]

2. Description of the Related Art Conventionally, in the case of treating sewage with an irregular inflow, the inflowing sewage is temporarily stored in a flow rate adjusting tank to make the organic concentration of the sewage uniform, and then supplied to the aeration tank in fixed amounts. is doing. Also, in the aeration tank, when solid-liquid separation is performed with an immersion type membrane separation device and the permeate is obtained as treated water, the liquid in the flow rate adjustment tank should be adjusted depending on the balance between the water supply to the aeration tank and the operation of the membrane separation device. It is necessary to control the water supply to the aeration tank and the start and stop of the membrane separation device depending on the level and the liquid level of the aeration tank. For example, in the conventional wastewater treatment device shown in FIG.
Water is sent from the flow rate adjusting tank 1 to the aeration tank 2 below the aeration tank liquid level height (H _2B ) and above the flow rate adjusting tank liquid level (H ₁ ), or the flow rate adjusting tank liquid level high (H ₁ ) → liquid The pump 5 is started at a low level (L ₁ ) and the aeration tank liquid level is low (L _2B ) or lower, and the flow rate adjustment tank liquid level is low (L ₁ ) or lower, or the aeration tank liquid level is high (H _2B ). Stop above. The operation of the membrane separation device 3 starts the pump 6 when the liquid level in the aeration tank is high (H _2A ) or more, and stops when the liquid level in the aeration tank is low (L _2A ) or less.

In this way, by setting the operating conditions for starting and stopping by the liquid level, when the amount of water sent from the flow rate adjusting tank 1 exceeds the amount of treated water of the membrane separation device 3, the liquid level of the aeration tank 2 rises. Then, the water supply is stopped at a high liquid level so as not to overflow from the aeration tank 2, and the membrane separator 3 is restarted when the liquid level is lowered by the operation. In addition, the amount of treated water in the membrane separation device 3 depends on the flow rate adjusting tank 1.
When the amount of water supplied from the aeration tank 2 is higher than that of the aeration tank 2, or when there is no water supplied to the aeration tank 2, the membrane separation device 3 stops at the liquid level of the aeration tank so that the immersed separation membrane is not on the liquid surface. When the liquid level rises due to the water supply of, it restarts. In operation of the aeration tank immersion type membrane separation device 3, the membrane separation device 3 is intermittently operated in order to prevent accumulation of a cake layer adhering to the surface of the separation membrane. That is, the separation membrane surface of the membrane separation device is always washed by the rising stirring flow generated by aeration, but by stopping the membrane separation device, the cleaning effect is enhanced and the cake layer is easily peeled off due to relaxation of the separation membrane. Moreover, since the amount of cake layer deposited during intermittent operation is smaller than during continuous operation, peeling is more likely to occur.

Further, in order to prevent the formation of a cake layer on the membrane surface of the membrane separation device, the shorter the operating time in the intermittent operation, the longer the rest time, the better, and the lower the flux (permeation velocity of the separation membrane). The better you set up and drive. The rising stirring flow generated by aeration for cleaning the membrane surface is
The flow velocity changes. In order to efficiently clean the membrane surface of the membrane separator, an appropriate amount of air is required for the flux during operation of the membrane separator. For example, if the amount of air is small, a cake layer is likely to be formed on the surface of the separation membrane. On the contrary, if the amount of air is too large, the stirring flow received by the separation membrane is too strong, which accelerates the deterioration and damage of the separation membrane. It will be. As described above, in the operation using the membrane separation device, a constant amount of the inflowing sewage is continuously flowed into the aeration tank from the flow adjustment tank as uniformly as possible, and the intermittent operation of the membrane separation device is performed. It is possible to extend the life of the membrane by continuously operating it with a reduced time ratio or a low flux.

The above control conditions are summarized as follows. Water level conditions Relationship between membrane separator operation control liquid level (H _2A , L _2A ) and flow control tank water supply control liquid level ((H _2B , L _2B ) H _2A ≤ H _2B , L _2A ≤ L _2B Operating condition Transfer pump startup Conditions: H ₁ or more and L _2B or less → H _2B holding state or H ₁ or more → L ₁ holding state and L _2B or less Stopping condition: L ₁ or less or H _2B or more Membrane separation device starting condition: H _2A or more or H _2A or more → L _2A holding state stop condition: L _2A or less

[0006] However, in order to correct the balance between the amount of water sent from the flow rate adjusting tank to the aeration tank and the amount of withdrawal due to the operation of the membrane separation device, depending on the liquid level of the flow rate adjusting tank and the aeration tank, the water is supplied to the aeration tank. It is necessary to control the start and stop of the membrane separation device. For this reason, the load for water supply or operation during the stop time for this correction must be added to the setting during operation. For example, if the amount of water sent from the flow rate adjustment tank is set to the amount that can be continuously supplied for 24 hours relative to the daily sewage amount, when the flow rate adjustment tank is at a low water level and the water supply to the aeration tank is stopped, After the separation device is activated and the liquid level in the aeration tank once becomes the stop liquid level in the membrane separation device, the flow of sewage into the flow adjustment tank starts the water supply from the flow adjustment tank and restarts the operation of the membrane separation device. It takes time to rise, and the down time of the membrane separation device during this time becomes a load during operation.

The operating flow rate of the membrane separator is 24 with respect to the amount of waste water.
When the amount that can be continuously operated for a time is set, once the aeration tank liquid level has reached the water supply stop liquid level from the flow rate adjustment tank, it is possible to restart water supply from the flow rate adjustment tank by operating the membrane separation device. It takes time, and it is necessary to consider the suspension time of water supply to the aeration tank during this period in the capacity of the flow rate adjusting tank. On the other hand, if the amount of water sent from the flow rate adjustment tank is set to be too large for the daily amount of sewage, a large amount of sewage will flow into the aeration tank at one time, and the remaining time will flow into the aeration tank. Since the membrane separation device continuously removes the treated water while repeating the operation and the intermittent operation after stopping, the treated water quality may be permeated through the membrane separation device without sufficient treatment temporarily. It causes deterioration and contamination of the separation membrane.

When the operating water amount of the membrane separation device is set to an excessively large amount of treated water with respect to the daily sewage amount, the formation of the cake layer adhering to the membrane surface is promoted. In addition, by operating the aeration device while the membrane separation device is stopped and there is no inflow of sewage, the rising agitated flow generated by aeration always cleans the membrane, but the separation occurs during the cleaning. The membrane is constantly under the flow load of this rising stir flow. If aeration is continued for a long time and excessive aeration is performed without expecting inflow of sewage, the surface of the membrane will be affected by the load of the rising stirring flow received on the separation membrane surface, even though the actual operating time of the membrane separation device is short. In addition, the membrane separator may be deteriorated or damaged earlier.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, smoothes the flow of sewage from inflow to discharge, and enables stable sewage treatment and efficient membrane separation operation. Another object is to provide a method for operating a sewage treatment apparatus that can prolong the life of the membrane separation apparatus.

[0010]

In order to solve the above problems, according to the present invention, a method for operating a sewage treatment apparatus in which water to be treated is once stored in a flow rate adjusting tank and then treated in an aeration tank having a membrane separator. In, the start and stop of the intermittent operation of the membrane separation device immersed in the aeration tank and the water supply operation of the sewage flowing into the flow rate adjusting tank, and the increase or decrease in the amount of sewage water sent from the flow rate adjusting tank and the operation of the membrane separating apparatus. And change the rest time of the rest,
The liquid level of the flow rate adjusting tank and the aeration tank, the water feeding time or water feeding amount from the flow rate adjusting tank, and the operation time or water amount of the membrane separation device are used.

Further, according to the present invention, in the method for operating a wastewater treatment device in which water to be treated is temporarily stored in a flow rate adjusting tank and then treated in an aeration tank having a membrane separator, the wastewater flowing into the flow rate adjusting tank is sent. Operation and start / stop of intermittent operation of the membrane separation device immersed in the aeration tank, adjustment of increase / decrease in the amount of waste water sent from the flow rate adjustment tank and change of the flux of the membrane separation apparatus are performed with the liquid of the flow rate adjustment tank and the aeration tank. The water supply time or water supply amount from the flow rate adjusting tank and the operation time or water amount of the membrane separation device. In the operating method, it is preferable that the operation of the aeration device of the aeration tank be an intermittent operation or an operation in which the amount of air supplied can be adjusted depending on the time when the water is fed from the flow rate adjusting tank and the membrane separator is stopped. It is preferable to increase / decrease the amount of air blown by the blower to the aeration tank or change the number of operating units according to the flux of the separation device.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a sewage treatment apparatus used in the present invention. In FIG. 1, a sewage inlet is provided in the flow rate adjusting tank 1, and the sewage 11 is temporarily stored in the flow rate adjusting tank 1. Liquid level gauge 9 and transfer pump (submersible pump) 5 in the tank
Is provided, and the waste water in the flow rate adjusting tank is transferred to the aeration tank 2 by the water supply pipe 12 from the transfer pump 5. A liquid level gauge 10 is also provided in the aeration tank 2, and an air diffuser 4 is installed near the bottom of the tank, and is connected to an aeration blower 7 arranged outside the tank through an air supply pipe 14. Further, the membrane separation device 3 is arranged at a position below the aeration tank liquid level L _2A above the air diffuser 4, and the membrane separation device 3 is always operated below the aeration tank liquid level during operation. There is. Piping 1 from membrane separator 3
It is connected to a treated water pump 6 arranged outside the tank through 5 and the permeate in the separation membrane can be obtained as treated water 13 via the treated water pump 6 by the suction operation of the treated water pump 6.

Flow rate adjusting tank liquid level meter 9, aeration tank liquid level meter 10,
The transfer pump 5, the treated water pump 6, and the aeration blower 7 are electrically connected to the control device 8. In the transfer pump 5, the treated water pump 6, and the aeration blower 7, the pump or the blower rotation speed is changed by the control device 8. However, the amount of water or the amount of air can be changed. 2 and 3 show schematic configuration diagrams of another sewage treatment apparatus used in the present invention. In FIG. 2, the pipes 12 and 1 of the transfer pump 5 and the treated water pump 6 are shown.
5 is provided with automatic valves 16 and 17, and FIG.
Has two transfer pumps 5 and two blowers 7.
Next, the operating method of the present invention will be described with reference to FIG.

In addition to the conventional operation method, when there is no inflow of sewage into the flow rate adjusting tank 1 and the flow rate adjusting tank 1 is below the low liquid level (L ₁ ) due to the water being sent to the aeration tank 2, the water is sent to the aeration tank 2. To stop. After that, the liquid level rises due to the inflow of sewage 11,
When the operating condition of the liquid level in the aeration tank is satisfied and the water level is lower than the liquid level in the flow control tank (L ₁ ) or more, water supply is started with a small amount of water. Sewage 1 into flow rate adjusting tank 1
1 continues, and when the flow rate adjusting tank 1 reaches the liquid level high (H ₁ ), the amount of water in the aeration tank 2 is increased. To adjust the amount of water sent from the flow rate adjusting tank 1 to the aeration tank 2, either change the rotation speed of the pump, or change the opening by adjusting the opening by installing an automatic valve or weir in the water supply pipe as shown in FIG. Alternatively, the number of pumps to be operated is changed as shown in FIG.

The water level from the flow rate adjusting tank 1 to the aeration tank 2 and the inflow of the dirty water 11 into the flow rate adjusting tank 1 are eliminated or reduced, and the liquid level in the flow rate adjustable tank is lowered to a high level (H ₁ )
The amount of water to be fed is reduced after a certain period of time while keeping the liquid level high (H ₁ ) or less. Sewage to the flow rate adjustment tank 11
When the liquid level becomes equal to or higher than the liquid level high (H ₁ ) due to the inflow of water, the amount of water to be returned is restored. Flow rate adjustment tank 1 has low liquid level (L ₁ )
Below, the water supply to the aeration tank 2 is stopped, the aeration tank liquid level is below the membrane separator operating liquid level (L _2A ), and the membrane separator 3
When the operation of the
The flow of water from the flow rate adjusting tank 1 starts, and the operating level of the membrane separation device becomes low (L _2A ) or more, and the time for sending water from the flow rate adjusting tank 1 elapses for a certain period of time or exceeds the certain amount of water. Then, the membrane separation device 3 starts the operation in a state where the operation time in the intermittent operation is shortened.

At this time, the cycle time of the intermittent operation may be kept constant to shorten the operation time and the rest time. Alternatively, the cycle time may be shortened to shorten the operation time and keep the rest time constant. May be. When the water supply from the flow rate adjusting tank is continued as it is, and the membrane separator operating liquid level height (H _2A ) or more is reached, the operating time in the intermittent operation of the membrane separator 3 is changed to a longer state. There is no inflow of sewage, and the flow control tank liquid level is low (L ₁ ) or less, and the aeration tank 2
When the water supply to the membrane is stopped, the membrane separator operating liquid level (H
_2A ) or less, or the membrane separator 3 continues to operate and falls below the membrane separator operating liquid level (H _2A ), and the membrane separator operating time elapses for a certain time, or the amount of treated water in the membrane separator If the amount of water exceeds a certain amount, the operating time in the intermittent operation of the membrane separation device 3 is shortened. At this time, when dirty water flows into the flow rate adjusting tank 1 to start water supply to the aeration tank 2, the operating time of the membrane separation device 3 is returned to the original setting.

The water level of the aeration tank 2 is raised by the water supply from the flow rate adjusting tank 1 to the aeration tank liquid level height (H _2B ) for the water supply operation from the flow rate adjusting tank 1 to the aeration tank 2 to supply the water. After the stop, the liquid level becomes below the flow rate adjusting tank water supply operation liquid level high (H _2B ) by the operation of the membrane separation device 3, and the membrane separation device operation time elapses for a certain period of time or the membrane separation device treated water amount is present. When the water amount is exceeded, the water supply from the flow rate adjusting tank 1 is started.
As a result, water can be sent from the flow rate adjusting tank 1 to the aeration tank 2 and the membrane separation device 3 can be operated at all times as much as possible. For this reason, the stop time of the water supply from the flow rate adjusting tank 1 to the aeration tank 2 is shortened, the amount of water supply per time that allows for the stop time can be reduced, and the load of the dirty water supply to the aeration tank 2 can be reduced. Because it can be relaxed
Stable sewage treatment can be performed in the aeration tank 2, and good treatment water can be transmitted to reduce the contamination of the separation membrane and prolong the life of the membrane.

Further, by reducing the stop time due to the liquid level of the aeration tank, the waste water stored in the flow rate adjusting tank 1 is sent to the aeration tank 2, so that the volume of the waste water that flows in unevenly can be increased. I can afford. The down time of the membrane separation device 3 is reduced, and it is not necessary to set the operation time during intermittent operation excessively in anticipation of the stop time during the operation of the membrane separation device, and to operate efficiently according to the inflow amount. You can Therefore, the cake layer attached to the membrane surface during operation is reduced, and the membrane surface can be easily cleaned by aeration, so that the life of the membrane of the membrane separation device 3 is extended. In addition, there is no liquid supply from the flow rate adjusting tank 1 to the aeration tank 2, and the membrane separator is stopped at a level lower than the aeration tank liquid level (L _2A ) in the membrane separator 3, and even after a certain period of time, When there is no inflow of sewage into the aeration tank, the aeration device 4 operates intermittently or in a state where the air supply amount is reduced. As a result, after performing an appropriate membrane cleaning effect at the time of stoppage, the deterioration of the separation membrane due to the rising stirring flow due to aeration, the progress of damage, etc. are suppressed, and the extra time during the treatment stoppage period in the aeration tank 2 is suppressed. Driving power can be reduced.

The amount of air blown by the aeration device 4 is adjusted by changing the number of revolutions of the aeration blower 7, or changing the number of operating aeration blowers 7 as shown in FIG. In the above operation, a similar result is obtained by changing the flux (permeation flow rate of the separation membrane) of the membrane separation device 3 instead of changing the operating time or the rest time or both times in the intermittent operation of the membrane separation device 3. To be Further, if the amount of aeration air is changed according to the flux of the membrane separation device 3, it is possible to supply aeration air according to the load, and it is possible to prevent excessive aeration and deterioration of processing. Furthermore, since the rising stirring flow generated by aeration is not excessively supplied to the membrane separation device, it is possible to suppress the damage of deterioration and breakage of the separation membrane and prolong the life of the membrane.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 FIG. 4 shows a schematic configuration diagram of an apparatus used in Examples. Figure 4
2 have the same meanings as in FIG. 1, and there is no difference in the device configuration. In FIG. 4, the flow rate adjusting tank liquid level meter 9 is arranged above the lower limit liquid level of the transfer pump 5 in the ascending order of L ₁ ,
Three points, M ₁ and H ₁ , are provided. The setting position is set in the lower part of the tank so that the difference in height between the liquid levels is as small as possible and the temporary inflow of a large amount of wastewater can be dealt with so as not to interfere with shaking of the liquid surface. The aeration tank level gauge 10 is arranged above the separation membrane in the order of LL ₂ , L ₂ , M ₂ and H _2.
4 points are provided. The set positions are set as small as possible so that the heights of the liquid levels do not interfere with each other due to fluctuations in the liquid level.

Basically, the operation of the transfer pump 5 is such that when the liquid level in the flow rate adjusting tank 1 rises due to the inflow of sewage and becomes equal to or higher than the flow rate adjusting tank liquid level M ₁ , the transfer pump 5 is activated and the aeration tank 2 is operated.
Start sending water to the plant with medium water volume. When the liquid level in the flow rate adjusting tank 1 is lowered by the water supply of the transfer pump 5 and becomes lower than the liquid level L ₁ , the water supply is stopped. While the transfer pump 5 is operating when the liquid level in the flow rate adjusting tank becomes M ₁ or more, the sewage 11
When the water flows in and becomes the liquid level H ₁ or more, the pump water supply amount is changed to a large water amount, and the water is sent by the transfer pump 5 until the liquid level in the flow rate adjusting tank 1 is lowered to the liquid level L ₁ or less. To stop. Further, when the aeration tank liquid level is lowered by the operation of the membrane separation device 3 and becomes equal to or lower than the liquid level M ₂ , the transfer pump 5 is activated and the water supply from the flow rate adjusting tank 1 to the aeration tank 2 is started. Stops at liquid level H ₂ or higher. Thus, the flow rate adjustment tank 1
Also, the basic operation is the start and stop in a liquid level cycle in which the liquid level in the aeration tank 2 is activated when both operating conditions are satisfied, and the operation is stopped when any of the stop conditions is satisfied.

In the aeration tank 2, the aeration blower 7 sends air to blow out the diffuser 4 from the inside of the tank to aerate the sewage flowing in from the flow rate adjusting tank 1 and to agitate it by the air lift action of air. The flow cleans the separation membrane surface of the membrane separation device 3. The permeated liquid 13 that has been solid-liquid separated is taken out through the treated water pump 6 by the negative pressure by operating the treated water pump 6 in this state.
The operation of the treated water pump 6 is basically such that when the liquid level in the aeration tank ₂ rises due to the inflow of sewage and becomes equal to or higher than the liquid level L ₂ in the aeration tank,
The treated water pump 6 is activated to start withdrawal by intermittent operation with a medium water amount. When the liquid level in the aeration tank 2 is lowered to the liquid level LL ₂ or less due to the withdrawal of the treated water pump 6, the withdrawal operation is stopped. When the treated water pump 6 is operating at the liquid level LL ₂ or more in the aeration tank and the sewage further flows into the tank to reach the liquid level M ₂ or more, the pump withdrawal amount is changed to a large water amount, and the transfer pump The water level of the aeration tank 2 is lowered by the water supply of No. 5 and the water is stopped by operating until the liquid level becomes LL ₂ or less. In this way, the basic operation is the start and stop in a liquid level cycle in which the liquid level of the aeration tank 2 is activated when the operating condition is satisfied, and is stopped when the stop condition is satisfied.

In addition to these basic operations, a control method in which a time setting is added as shown in Table 1 is used.

[Table 1]

The water volume setting of the transfer pump is as shown in Table 2,
The controller controls the rotational speed of the transfer pump according to the liquid level and elapsed time detected by the liquid level gauge 9 of the flow rate adjusting tank and the liquid level and elapsed time detected by the aeration tank liquid level gauge 10. Adjust the water flow rate.

[Table 2] Q: Average daily inflow of wastewater [m ³ / day]

The water amount of the treated water pump 6 is set by the liquid level and elapsed time detected by the liquid level gauge 9 of the flow rate adjusting tank in the controller and the aeration tank level gauge 10 as shown in Table 3 or Table 4. Depending on the liquid level and the elapsed time detected as described above, the operation and pause times in the intermittent operation are changed.

[Table 3]

[0026]

[Table 4]

As a result, it is possible to shorten the down time of the transfer pump 5 and the treated water pump 6 from the stop liquid level to the starting liquid level, and operate the pump as long as possible. For this reason, it is possible to reduce the load of water supply during a pause during operation, and by reducing the strength and fluctuation of the supply load of dirty water to the aeration tank 2, a stable and efficient operation is achieved in the aeration tank 2, Stable treatment of sewage can be performed, and good treatment of sewage allows permeation of the membrane to be reduced, thereby prolonging the life of the membrane. Moreover, since the stop time of the intermittent operation of the membrane separation device is shortened, the ratio of the operating time during the intermittent operation of the membrane separation device 3 can be reduced, so that the cake layer adhered to the membrane surface during the intermittent operation is small. As a result, the separation membrane surface can be easily cleaned during aeration, and the life of the separation membrane can be extended.

The liquid levels in the flow rate adjusting tank 1 and the aeration tank 2 decrease, and the transfer pump 5 and the treated water pump 6 come to a stop condition liquid level. The aeration blower 7 operates intermittently until the operating conditions of the pump are satisfied. The ratio of the intermittent operation and the suspension of the aeration blower 7 is set within a range in which the state where the wastewater treatment function of the aeration tank 2 does not deteriorate can be maintained. As a result, the rising agitation flow caused by aeration by the aeration blower operation is not received more than necessary on the separation membrane surface,
It is possible to slow the progress of deterioration and damage of the separation membrane when the membrane separation device is stopped.

Then, in the control device 8, as shown in Table 1, the liquid level and elapsed time detected by the liquid level gauge 9 of the flow rate adjusting tank and the liquid level and elapsed time detected by the aeration tank liquid level gauge 10 are shown. In order to reduce the loss of the treatment amount due to the downtime, the controller 8 adjusts the water amount setting of the transfer pump 5 as shown in Table 2, and the water amount setting of the treated water pump 6 is set in Table 5. By changing the flux as described above, it is possible to reduce the load of water supply during the rest period during operation, and by reducing the strength and fluctuation of the supply load of dirty water to the aeration tank 2, 2 becomes stable and efficient operation,
Stable treatment of sewage can be performed, and good treatment of sewage allows permeation of the membrane to be reduced, thereby prolonging the life of the membrane. In addition, since the down time can be shortened, the flux during operation of the membrane separation device can be reduced, so that the cake layer adhering to the membrane surface during operation is reduced, and the separation membrane surface can be easily cleaned during aeration. The life of the separation membrane and the power cost of the aeration blower can be reduced.

[0030]

[Table 5]

Further, as shown in Table 5, the amount of air blown by the aeration blower is adjusted according to the change in the flux of the membrane separation device, so that the separation membrane surface is washed with an ascending stirring flow by appropriate aeration and excessive stirring is performed. It is possible to prevent the deterioration of the film and the progress of damage from being accelerated by the flow. In addition, the aeration blower operates intermittently when the transfer pump and the treated water pump are stopped for a certain period of time, so that when the membrane separation device is stopped, the rising stirring flow caused by aeration by the aeration blower operation is generated on the separation membrane surface. Therefore, the deterioration and damage of the separation membrane can be slowed down.

[0032]

As described above, according to the present invention, the flow rate is changed according to the liquid level and the elapsed time detected by the liquid level meter of the flow rate adjusting tank and the liquid level and the elapsed time detected by the aeration tank liquid meter. By changing the amount of water sent from the adjusting tank to the aeration tank and the ratio of the operation time in the intermittent operation of the membrane separation device, the standby time until startup due to the liquid level conditions should be shortened and the operation should be performed as continuously as possible. You can For this reason, the loss of the processing amount due to the downtime is reduced, and it is possible to reduce the amount of water to be sent from the flow rate adjustment tank to the aeration tank per unit time in anticipation of the stop time, and to reduce the wastewater supply load to the aeration tank. By mitigating the strength and weakness, stable treatment of sewage can be performed in the aeration tank, and the permeation of good treated water reduces the contamination of the separation membrane and prolongs the life of the membrane. In addition, since the wastewater stored in the flow rate adjusting tank is sent to the aeration tank, it is possible to make room for the capacity to store the wastewater that flows in unevenly.

It is not necessary to set the operating time during the intermittent operation excessively in consideration of the stop time during the operation of the membrane separation device, and the operation can be efficiently performed according to the inflow amount. Therefore, the cake layer attached to the membrane surface during operation is reduced, the membrane surface can be easily cleaned by aeration, and the life of the membrane of the membrane separation device is extended. In addition, when there is no liquid supply from the flow rate adjustment tank to the aeration tank and the membrane separation device is stopped, and there is no inflow of dirty water into the aeration tank after a certain period of time, the aeration device operates intermittently or sends air. By performing the process with a small amount, it is possible to suppress the progress of deterioration and damage of the separation membrane, and reduce the extra operation power during the process suspension period in the aeration tank.

By reducing the waiting time before starting depending on the liquid level condition and performing the continuous operation as much as possible,
Since the amount of processing loss due to downtime is reduced and the flux during operation of the membrane separator can be reduced, the separation membrane surface can be easily cleaned during aeration, and the life of the separation membrane and the power cost of the aeration blower can be reduced. Can be reduced.
In addition, as shown in Table 5, by adjusting the amount of air blown by the aeration blower according to the change in the flux of the membrane separation device, the separation membrane surface is washed with a rising stirring flow by appropriate aeration,
It is possible to prevent the deterioration of the membrane and the progress of damage from being accelerated by the excessive stirring flow. When the transfer pump and treated water pump are stopped and the aeration blower operates intermittently after a certain period of time, when the membrane separation device is stopped, the rising stirring flow generated by aeration by the aeration blower operation is separated. The membrane surface will not be unnecessarily received, and the progress of deterioration and breakage of the separation membrane can be slowed down.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sewage treatment apparatus used in the present invention.

FIG. 2 is a schematic configuration diagram of another sewage treatment apparatus used in the present invention.

FIG. 3 is a schematic configuration diagram of another sewage treatment apparatus used in the present invention.

FIG. 4 is a schematic configuration diagram of a sewage treatment apparatus used in the examples.

FIG. 5 is a schematic configuration diagram of a conventional sewage treatment apparatus.

[Explanation of Codes] 1: Flow rate adjusting tank, 2: Aeration tank, 3: Membrane separation device, 4: Air diffuser, 5: Transfer pump, 6: Treated water pump, 7: Aeration blower, 8: Control device, 9 : Flow rate adjustment tank liquid level meter, 10:
Aeration tank liquid level meter, 11: dirty water, 12: transfer pipe, 13: treated water, 14: air supply pipe, 15: pipe, 16, 17: adjusting valve

Continuation of front page (56) References JP-A-8-39089 (JP, A) JP-A-4-190889 (JP, A) JP-A-63-69594 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) C02F 3/12

Claims (4)

(57) [Claims] 1. A method for operating a sewage treatment apparatus in which water to be treated is temporarily stored in a flow rate adjusting tank and then treated in an aeration tank having a membrane separation device. Starting and stopping the intermittent operation of the membrane separator immersed in the water, adjusting the increase or decrease in the amount of sewage fed from the flow rate adjusting tank, and changing the intermittent time of the operation and suspension of the membrane separating apparatus. A method for operating a sewage treatment apparatus, which is performed according to a liquid level, a water supply time or water supply amount from a flow rate adjusting tank, and an operation time or a water amount of a membrane separation device. 2. A method of operating a sewage treatment apparatus in which water to be treated is temporarily stored in a flow rate adjusting tank and then treated in an aeration tank having a membrane separation device. Start and stop the intermittent operation of the membrane separator immersed in the water, adjust the increase or decrease in the amount of sewage sent from the flow rate adjusting tank and change the flux of the membrane separating apparatus, adjust the liquid level in the flow rate adjusting tank and the aeration tank, and change the flow rate. A method for operating a sewage treatment apparatus, characterized in that the operation is performed depending on the time or amount of water supplied from the adjusting tank and the operation time or amount of water of the membrane separation device. 3. The operation method according to claim 1, wherein the operation of the aeration device of the aeration tank is an intermittent operation or an operation in which the amount of air supplied can be adjusted depending on the time when water is supplied from the flow rate adjusting tank and the membrane separation device is stopped. The method for operating the sewage treatment apparatus according to claim 1 or 2, which is characterized in that. 4. The sewage treatment apparatus according to claim 2, wherein, in the operating method, the amount of air blown by the blower to the aeration tank is increased or decreased or the number of operating units is changed according to the flux of the membrane separation device. Driving method.