JP3738115B2 - Sewage treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sewage treatment apparatus. More specifically, the present invention is used to treat sewage such as domestic wastewater and industrial wastewater, and removes organic matter and nitrogen from the sewage by the action of activated sludge, and also uses a filtration membrane to form a solid liquid. The present invention relates to a sewage treatment apparatus that separates and leaves activated sludge while allowing filtrate to flow out.
[0002]
Conventionally, as this kind of sewage treatment apparatus, an aeration tank for aeration of sewage to perform activated sludge treatment, and a filtration membrane apparatus provided in this aeration tank for solid-liquid separation of the activated sludge mixed liquid in the tank by filtration The suction pump connected to the filtration membrane device is provided in a suction path connecting the filtration membrane device and the suction pump, and the suction pump for sucking the filtrate from the device and flowing out to the outside. What is provided with the pressure gauge for measuring a negative pressure is known.
[0003]
In such a sewage treatment device, when the suction negative pressure of the suction pump measured by the pressure gauge exceeds a certain value, it is judged that the filtration membrane device has stopped functioning normally, and the filtration membrane device is cleaned or replaced. And so on.
[0004]
[Problems to be solved by the invention]
According to such a sewage treatment apparatus, since it has a relatively complicated and expensive pressure gauge, the structure of the apparatus is complicated, and maintenance and inspection are troublesome, and the cost of the apparatus is high. There was a problem.
[0005]
The present invention has been made in consideration of such circumstances, and it is an object of the present invention to provide a sewage treatment apparatus that is simple in structure, easy to maintain and inspect, and that can reduce the cost of the apparatus. And
[0006]
[Means for Solving the Problems]
According to the present invention, an aeration tank for performing aeration when activated sludge treatment is applied to sludge, and a filtration membrane device that is provided inside the aeration tank and separates the activated sludge mixed liquid in the tank by solid-liquid separation by filtration. A suction pump connected to the filtration membrane device for sucking purified water as filtrate by the device and flowing it out, a motor for driving the suction pump, and a current sensor for detecting a current flowing through the motor And a control unit electrically connected to the current sensor and the motor, and the control unit determines that the membrane clogging of the filtration membrane device has occurred based on the rate of change of the current detected by the current sensor. A sewage treatment apparatus is provided.
[0007]
In the aeration tank, for example, an aeration pipe connected to an air supply means outside the tank is arranged on the bottom of the tank, etc., and sewage (treated water) introduced from a sewage introduction pipe or the like is treated with activated sludge placed in the tank. Use to biologically process under aerobic conditions.
[0008]
The filtration membrane device solid-liquid separates the activated sludge mixed liquid (mixed liquid of activated sludge and treated water) in the tank into activated sludge and filtrate (purified water or treated water) by filtration. As the filtration membrane device, for example, a device in which one filtration membrane body is arranged inside a box-shaped casing that opens up and down or a plurality of filtration membrane plates are arranged in parallel is used. Such a filtration membrane device is detachably or fixedly provided inside the aeration tank. When the filtration membrane device is detachably provided, its maintenance, inspection and cleaning are facilitated. More preferably, the filtration membrane body or the filtration membrane plate is provided at a position where it comes into contact with the aeration air supplied by the aeration tube. This is because the membrane surface can be cleaned with aeration air.
[0009]
The suction pump is for sucking purified water or treated water, which is a filtrate by the filtration membrane device, to flow out to the outside, and is disposed, for example, above the outside of the aeration tank. The suction pump is connected to the upper part of the casing where the filtrate collected by the filtration membrane device is collected via a suction pipe. This suction pump is driven by a motor in consideration of ease of control.
[0010]
The current sensor detects the current flowing through the motor, and thereby detects the change -increase or decrease in the suction negative pressure of the suction pump applied to the filtration membrane device. Then, if the suction negative pressure of the suction pump increases to a certain value, the filtration membrane body and the filtration membrane plate of the filtration membrane device are blocked (the solid matter such as activated sludge adheres excessively to a part or the whole of the membrane). It is determined that the filtration membrane device has deteriorated in function, such as clogging). This determination may be performed by a person such as a user or administrator of the sewage treatment apparatus , but is preferably performed by a control unit described below.
[0011]
Control unit is electrically connected to at least a current sensor and a motor, at least, it determines that the membrane clogging of the filtration membrane apparatus by the change rate of the current detected by the current sensor to control these occur.
[0012]
The sewage treatment apparatus according to the present invention is preferably configured such that the control unit instructs the motor to reduce or increase the rotation speed of the suction pump in accordance with the rate of change of the current detected by the current sensor. .
[0013]
Here, the rate of change of current refers to the rate of decrease or increase in current value within a certain time. Further, the number of rotations of the suction pump is reduced by reducing the suction negative pressure of the suction pump when it is determined that the filter membrane device is partially blocked from the rate of change of the current detected by the current sensor. This is because the solid matter such as activated sludge adhering to the filtration membrane device is peeled off to partially remove the blockage, or to extend the time until the filtration membrane device is completely blocked. On the other hand, the rotation speed of the suction pump is increased in order to resume normal operation when the function of the filtration membrane device returns to normal.
[0014]
According to the sewage treatment apparatus configured as described above, troubles related to the filtration membrane apparatus can be prevented in advance and effectively by automatic control by the control unit.
[0015]
Preferably, the sewage treatment apparatus according to the present invention further includes a chemical tank connected to the suction pump for storing the cleaning chemical liquid of the filtration membrane apparatus, and the motor and the suction pump are capable of rotating forward and reverse. The unit is configured to supply the chemical solution in the chemical solution tank to the filtration membrane device by rotating the motor and the suction pump in reverse according to the rate of change of the current detected by the current sensor.
[0016]
The cleaning chemical used here is preferably a chlorine-based chemical such as sodium hypochlorite. For example, the chemical liquid tank is connected to the downstream side of the suction pump, and the supply of the chemical liquid into the suction pump and its stop are switched by the switching valve. The reason why the motor and suction pump can rotate forward and backward is that when the chemical solution in the chemical solution tank is supplied to the filtration membrane device via the suction pump, it is necessary to reversely rotate the motor and suction pump. is there.
[0017]
Preferably, the sewage treatment apparatus according to the present invention further includes a notification unit for notifying the outside of the replacement time of the filtration membrane device, and the control unit notifies the change unit according to the rate of change of the current detected by the current sensor. Is configured to instruct the notification.
[0018]
Here, as the notification unit, for example, a visual notification unit such as an LED lamp and an audible notification such as a buzzer are used alone or in combination. Such a notification unit is electrically connected to the control unit. And according to the rate of change of the current detected by the current sensor, the control unit instructs the notification unit to notify the replacement time of the filtration membrane device.
[0019]
When the sewage treatment apparatus is configured in this way, the user or administrator can know the replacement time of the filtration membrane apparatus by visual and / or audible notification from the notification unit.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited thereby.
[0021]
As shown in FIG. 1, a sewage treatment apparatus D according to one embodiment of the present invention includes a flow rate adjustment tank 1 and an aeration tank 2 provided adjacent thereto. In the flow rate adjustment tank 1, sewage (water to be treated) to be treated flows from above and is stored. The sewage in the flow rate adjusting tank 1 is pumped up by a constant amount by the flow rate adjusting pump 3 and flows into the aeration tank 2.
[0022]
Activated sludge is put in the aeration tank 2 in advance. This activated sludge mixes with the inflowing sewage to become an activated sludge mixed solution. A filtration membrane device 4 is provided at the inner center of the aeration tank 2 so as to be immersed in the water to be treated.
[0023]
The filtration membrane device 4 includes a box-shaped casing 5 that opens up and down, a plurality of filtration membrane plates 6 that are detachably suspended in parallel above and inside the casing 5, and these filtration membrane plates 6. And a suction header 7 attached to the upper end of the head. The suction header 7 of the filtration membrane device 4 is connected to a suction pump 8 attached to the upper outer portion of the aeration tank 2 via a suction pipe 9.
[0024]
Each filtration membrane plate 6 solid-liquid separates the activated sludge mixed liquid in the aeration tank 2 into activated sludge and filtrate by a filter medium attached to the surface. The filtrate that has passed through the filter medium collects in the suction header 7, and flows out of the aeration tank 2 as purified water or treated water by the suction pump 8 through the suction pipe 9.
[0025]
An aeration pipe 19 is disposed horizontally in the lower part inside the casing 5 of the filtration membrane device 4 (location near the tank bottom). The aeration pipe 19 is connected to an aeration blower 10 that is an air supply means disposed outside the aeration tank 2, and supplies aeration air into the casing 5 by the operation of the blower 10. This aeration air aerates the activated sludge mixed liquid inside the casing 5 and touches each filtration membrane plate 6 to clean the membrane surface.
[0026]
The suction pump 8 is driven by a motor 11. Further, the suction pump 8 is connected to the chemical liquid tank 13 through an electromagnetic valve 12 which is a switching valve arranged on the downstream side thereof. The chemical liquid tank 13 stores sodium hypochlorite which is a chemical liquid for cleaning the filtration membrane plate 6. The solenoid valve 12 switches between supply of the chemical solution into the suction pump 8 in the chemical solution tank 13 and its stop (the state in which the filtrate can flow out).
[0027]
As shown in FIG. 2, the motor 11 and the electromagnetic valve 12 are controlled by a motor control circuit 15 and a microcomputer 16 that are electrically connected control units 14. The motor 11 and the control unit 14 are electrically connected to a current sensor 17 that detects a current flowing through the motor 11.
[0028]
The suction pump 8 and the motor 11 can be rotated forward and backward. That is, when the motor 11 rotates in the forward direction, the suction pump 8 also rotates in the forward direction, and the filtrate flows out of the aeration tank 2, and when the motor 11 rotates in the reverse direction, the suction pump 8 also rotates in the reverse direction. It supplies the inside of the filtration membrane plate 6 through the suction pump 8. These controls are performed according to instructions from the control unit 14 in accordance with the rate of change of current detected by the current sensor 17.
[0029]
The sewage treatment apparatus D is provided with an LED lamp 18 as a visual notification unit for notifying the outside of the replacement time of the filtration membrane plate 6 of the filtration membrane device 4. The LED lamp 18 is connected to the microcomputer 16, and if the rate of change of the current detected by the current sensor 17 is equal to or greater than a predetermined value, the microcomputer 16 gives an instruction to turn on the lamp.
[0030]
Below, based on the flowchart of FIG. 3, operation | movement of this waste water treatment apparatus D is demonstrated in detail.
[0031]
When the rate of change of the current detected by the current sensor 17 after starting the operation of the sewage treatment apparatus D increases beyond a certain value, and the membrane clogging (partial blockage) of the filtration membrane plate 6 occurs, the control unit 14 When the determination is made, the rotational speeds of the motor 11 and the suction pump 8 are decreased from the standard values and the operation is continued for a certain time.
[0032]
Here, the number of rotations of the motor 11 and the suction pump 8 is reduced by reducing the suction negative pressure of the suction pump 8, and solids such as activated sludge adhering to the filtration membrane plate 6 are peeled off and partly. This is to eliminate the blockage or extend the time until all the filtration membrane plates 6 are blocked.
[0033]
Thereafter, the control unit 14 returns the rotational speeds of the motor 11 and the suction pump 8 to standard values, and the current flowing through the motor 11 is confirmed by the current sensor 17. Here, if the current is reduced to an allowable value, it is determined that the function of the filtration membrane plate 6 is normal, and the normal operation is resumed. On the other hand, when the current has not decreased to the allowable value, the control unit 14 switches the electromagnetic valve 12 to the chemical solution supply side. Next, the motor 11 and the suction pump 8 are reversely rotated, and the chemical solution in the chemical solution tank 13 is supplied to the inside of the filtration membrane plate 6 through the suction pump 8 to clean the filtration membrane plate 6.
[0034]
Thereafter, the control unit 14 switches the motor 11 and the suction pump 8 to normal rotation, returns the rotation number to the standard value, and checks the current flowing through the motor 11 by the current sensor 17. Here, if the current is reduced to an allowable value, it is determined that the function of the filtration membrane plate 6 is normal, and the normal operation is resumed. On the other hand, if the current has not decreased to the allowable value, it is determined that the blockage exceeding the allowable range of the filtration membrane plate 6 has occurred, and the control unit 14 notifies the replacement timing of the filtration membrane plate 6 to the outside. An instruction to turn on the LED lamp 18 is given.
[0035]
【The invention's effect】
According to the invention of claim 1, an aeration tank for performing aeration when performing activated sludge treatment on sludge, and filtration for solid-liquid separation of the activated sludge mixed liquid in the tank provided inside the aeration tank by filtration A membrane device, a suction pump connected to the filtration membrane device for sucking purified water as filtrate by the device and flowing it out, a motor for driving the suction pump, and a current flowing through the motor are detected The filter membrane device is clogged due to the rate of change of the current detected by the current sensor, and a control unit electrically connected to the current sensor and the motor. since determining, relatively, it is possible structure is omitted complex and expensive pressure gauge, not only even maintenance and inspection is facilitated, it is possible to reduce the cost of the apparatus, the filtration membrane apparatus film Can be automatically performed by the control unit determines that Mari has occurred.
[0036]
According to the invention of claim 2, since the control unit instructs the motor to decrease or increase the rotation speed of the suction pump in accordance with the rate of change of the current detected by the current sensor, automatic control by the control unit Thus, troubles related to the filtration membrane device can be prevented in advance and effectively.
[0037]
According to the third aspect of the present invention, the apparatus further includes a chemical tank connected to the suction pump for storing the cleaning chemical liquid of the filtration membrane device, wherein the motor and the suction pump can be rotated forward and backward, and the control unit is Since the chemical solution in the chemical solution tank is supplied to the filtration membrane device by rotating the motor and the suction pump in reverse according to the change rate of the current detected by the current sensor, the filtration membrane is obtained from the change rate of the current detected by the current sensor. When it is determined that the device is partially blocked, the motor and suction pump are rotated in reverse to supply the chemical solution in the chemical solution tank to the filtration membrane device. Things can be washed.
[0038]
According to the fourth aspect of the present invention, the apparatus further includes a notifying unit for notifying the outside of the replacement time of the filtration membrane device, and the control unit is connected to the notifying unit according to the rate of change of the current detected by the current sensor. Since the notification instruction is given, the user or administrator of the sewage treatment apparatus can know the replacement time of the filtration membrane device by visual and / or auditory notification from the notification unit.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of a sewage treatment apparatus according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a part of the sewage treatment apparatus of FIG. 1;
FIG. 3 is a flowchart for explaining the operation of the sewage treatment apparatus of FIG. 1;
[Explanation of symbols]
2 Aeration tank 4 Filtration membrane device 5 Casing 6 Filtration membrane plate 8 Suction pump 11 Motor 12 Solenoid valve 13 Chemical liquid tank 14 Control unit 15 Motor control circuit 16 Microcomputer 17 Current sensor 18 LED lamp 19 Aeration tube

Claims (4)

An aeration tank for performing aeration when performing activated sludge treatment on sewage, a filtration membrane device provided inside the aeration tank for solid-liquid separation of the activated sludge mixed liquid in the tank, and this filtration membrane device A suction pump that is connected and sucks purified water that is filtrated by the apparatus and flows it out, a motor that drives the suction pump, a current sensor that detects a current flowing through the motor, a current sensor, And a control unit electrically connected to the motor, wherein the control unit determines that the membrane clogging of the filtration membrane device has occurred according to the rate of change of the current detected by the current sensor. Processing equipment. The sewage treatment apparatus according to claim 1, wherein the control unit instructs the motor to reduce or increase the number of rotations of the suction pump according to the rate of change of the current detected by the current sensor. A chemical tank is further connected to the suction pump to store the cleaning chemical for the filtration membrane device, and the motor and the suction pump can be rotated forward and backward, and the controller detects the current detected by the current sensor. The sewage treatment apparatus according to claim 1 or 2, wherein the chemical liquid in the chemical liquid tank is supplied to the filtration membrane apparatus by rotating the motor and the suction pump in reverse according to the rate of change. A notification unit for notifying the outside of the replacement time of the filtration membrane device is further provided, and the control unit instructs the notification unit according to the rate of change of the current detected by the current sensor. The sewage treatment apparatus according to any one of 3 above.

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