JP6822833B2 - Wastewater treatment system and wastewater treatment method - Google Patents

Description

Embodiments of the present invention relate to wastewater treatment systems and wastewater treatment methods.

Wastewater discharged from food factories contains more oil and pollutants than domestic wastewater. In such wastewater treatment, a primary treatment is performed by an anaerobic treatment method or the like, and then a secondary treatment is performed by an activated sludge method. In the secondary treatment by the activated sludge method, organic substances that could not be completely decomposed in the primary treatment are decomposed by aerobic microorganisms (activated sludge) in the aerobic treatment tank. In the wastewater treatment system using the activated sludge method, the amount of aeration is controlled by controlling the flow rate (aeration amount) of the air supplied into the aerobic treatment tank according to the amount of pollutants in the aerobic treatment tank. The aeration amount control increases the amount of aeration supplied to the aerobic treatment tank because the amount of oxygen required in the aerobic treatment tank increases when the amount of pollutants in the aerobic treatment tank increases. Take control. On the other hand, when the amount of pollutants in the aerobic treatment tank decreases, the amount of oxygen required in the aerobic treatment tank decreases, so control is performed to reduce the amount of aeration.

Here, the amount of pollutants in the wastewater discharged from the food factory fluctuates greatly depending on the season and the day. On the other hand, the aeration device has a maximum aeration amount and a minimum aeration amount determined by the size of the device and the aeration capacity. Therefore, in the above-mentioned aeration amount control, when the amount of pollutant substances in the wastewater discharged from the factory is remarkably reduced, the aeration amount in the aerobic treatment tank may become excessive. When the amount of aeration in the aerobic treatment tank becomes excessive, aggregates (flocks) of aerobic microorganisms are disassembled, and the flocs do not settle in the settling tank installed on the downstream side of the aerobic treatment tank, resulting in deterioration of water quality. There is a risk.

Japanese Patent No. 5714355 Japanese Patent No. 5878231 Japanese Unexamined Patent Publication No. 2012-228645

An object to be solved by the present invention is to provide a wastewater treatment system and a wastewater treatment method capable of maintaining the water quality of treated water in a good state.

The wastewater treatment system of the embodiment includes a raw water tank, a primary treatment tank, an aerobic treatment tank, a water supply means, an aeration means, a sensor, and a control device.
The control device calculates a target aeration amount based on the processing index value measured by the sensor, and when the target aeration amount exceeds the minimum aeration amount of the aeration means, the aeration amount in the aeration means is set to the target aeration amount. When the target aeration amount is less than the minimum aeration amount, the aeration amount in the aeration means is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank by the water supply means.

The block diagram of the wastewater treatment system in the basic form. The block diagram of the wastewater treatment system in 1st Embodiment. The block diagram of the wastewater treatment system in 2nd Embodiment.

Hereinafter, the wastewater treatment system and the wastewater treatment method of the embodiment will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing a wastewater treatment system which is a basic form.
The wastewater treatment system 100 shown in FIG. 1 includes a raw water tank 1, a primary treatment tank 2, an aerobic treatment tank 3, a settling tank 4, a sensor 5, an aeration means 21, and a control device 10. The control device 10 is provided with an aeration amount calculation unit 8 and an aeration amount control unit 9. Further, the aeration means 21 includes a blower 6, an air supply line L6, and an aeration unit 7.

Raw water discharged from the factory is stored in the raw water tank 1. Further, a raw water supply line L1 is connected to the raw water tank 1. A pump P1 is provided in the middle of the raw water supply line L1. Here, in the present specification, the wastewater discharged from the factory is raw water, the wastewater treated in the primary treatment tank is the primary treated water, and the wastewater treated in the aerobic treatment tank is the secondary treated water. The wastewater separated into solid and liquid in the settling tank is described as the supernatant liquid.

The primary treatment tank 2 treats the raw water sent from the raw water tank 1 by the raw water supply line L1. In the primary treatment tank 2, treatment is performed by a methane fermentation treatment method, which is an anaerobic treatment method, or a carrier fluidized bed method, which is an aerobic treatment method. The primary treatment water supply line L2 is connected to the primary treatment tank 2.

In the aerobic treatment tank 3, the aerobic microorganisms held in the aerobic treatment tank 3 aerobically treat the primary water to be treated, which is sent from the primary treatment tank 2 by the primary water line L2. In the aerobic treatment tank 3, treatment is performed by the so-called activated sludge method. The aerobic treatment tank 3 is provided with a sensor 5 and an aeration unit 7. Further, a secondary water treatment line L3 is connected to the aerobic treatment tank 3.

The sensor 5 measures the treatment index value of the primary water to be treated during the aerobic treatment in the aerobic treatment tank 3. The sensor 5 is immersed in the primary water to be treated in the aerobic treatment tank 3. Further, the sensor 5 is connected to the aeration amount calculation unit 8 described later.

The aeration section 7 of the aeration means 21 aerates the primary water to be treated in the aerobic treatment tank 3. The aeration section 7 is immersed in the primary water to be treated at the bottom of the aerobic treatment tank 3. Further, the aeration unit 7 is connected to the blower 6 via the air supply line L6.

In the settling tank 4, the secondary treated water sent from the aerobic treatment tank 3 by the secondary treated water water supply line L3 is allowed to stand for a predetermined time, and solid-liquid separated into the supernatant liquid and the floc. The settling tank 4 has a supernatant discharge line L4 for discharging the supernatant liquid to the outside of the system, a sludge return line L5 for returning a part of the settled flocs to the aerobic treatment tank 3, and discharging the remaining flocs to the outside of the system. Is connected to a sludge discharge line (not shown).

The aeration amount calculation unit 8 of the control device 10 calculates the target aeration amount based on the processing index value in the aerobic processing tank 3 measured by the sensor 5. Further, the aeration amount calculation unit 8 is connected to the aeration amount control unit 9, and outputs the calculated target aeration amount to the aeration amount control unit 9.

A blower 6 is connected to the aeration amount control unit 9 of the control device 10. The aeration amount control unit 9 determines the target rotation speed of the blower 6 based on the target aeration amount output from the aeration amount calculation unit 8, and controls the blower 6 so as to reach the target rotation speed. When the rotation speed of the blower 6 reaches the target rotation speed, the aeration amount supplied from the aeration unit 7 becomes the target aeration amount.

The wastewater treatment method includes a step of treating the water to be treated sent from the raw water tank 1 in the primary treatment tank 2 and a step of treating the primary water to be treated sent from the primary treatment tank 2 in the aerobic treatment tank 3. And a step of solid-liquid separation of the secondary water to be treated sent from the aerobic treatment tank 3 in the settling tank 4. Each stage will be described below.

The raw water discharged from the factory is stored in the raw water tank 1. The raw water stored in the raw water tank 1 is sent to the primary treatment tank 2 via the raw water supply line L1 by the operation of the pump P1.

The raw water sent to the primary treatment tank 2 is treated by the microorganisms retained in the primary treatment tank 2. The treatment method performed in the primary treatment tank 2 is a methane fermentation treatment method, which is an anaerobic treatment method, or a carrier fluidized bed method, which is an aerobic treatment method. The primary treated water treated in the primary treated tank 2 is sent to the aerobic treatment tank 3 via the primary treated water water supply line L2.

The primary water to be treated that has been sent to the aerobic treatment tank 3 is aerobic-treated by aerobic microorganisms held in the aerobic treatment tank 3. The aerobic microorganisms in the aerobic treatment tank 3 consume oxygen in the air supplied from the aeration unit 7 to decompose pollutants in the primary water to be treated. The secondary treated water aerobically treated in the aerobic treatment tank 3 is sent to the settling tank 4 together with the aerobic microorganisms via the secondary treated water water supply line L3.

The secondary water to be treated, which has been sent to the settling tank 4, is allowed to stand for a predetermined time to be solid-liquid separated into flocs and a supernatant liquid. The supernatant liquid is discharged to the outside of the system via the supernatant liquid discharge line L4. In addition, some of the flocs that have settled at the bottom of the settling tank 4 are returned to the aerobic treatment tank 3 via the sludge return line L5, and the remaining flocs are discharged to the outside of the system via a sludge discharge line (not shown). ..

Here, in the above-mentioned aerobic treatment tank 3, when the amount of aeration supplied from the aeration unit 7 is insufficient, the dissolved oxygen concentration in the aerobic treatment tank 3 decreases, and the pollutant substance is decomposed by the aerobic microorganisms. It disappears. Therefore, in the wastewater treatment method, the aeration amount control described below is performed.

First, the treatment index value of the primary water to be treated in the aerobic treatment tank 3 is measured by the sensor 5 submerged in the primary water to be treated in the aerobic treatment tank 3. The treatment index value of the primary water to be treated measured by the sensor 5 is output to the aeration amount calculation unit 8. As for the treatment index value of the primary water to be treated, the treatment index value decreases as the amount of pollutants in the primary water to be treated increases, and the treatment index value increases as the amount of pollutants in the primary water to be treated decreases. Examples of such processing index values include dissolved oxygen concentration and redox potential.

The aeration amount calculation unit 8 calculates the target aeration amount to be supplied to the aerobic treatment tank 3 based on the treatment index value of the primary water to be treated output from the sensor 5. The target value of the aeration amount calculated by the aeration amount calculation unit 8 is output to the aeration amount control unit 9. The target aeration amount is an aeration amount at which the treatment performance of the aerobic treatment tank 3 is maintained well.

The aeration amount control unit 9 determines the rotation speed of the blower 6 based on the target aeration amount output from the aeration amount calculation unit 8, and controls the blower 6 so as to be the rotation speed. Specifically, the aeration amount control unit 9 controls to increase the rotation speed of the blower when the target aeration amount is high and decrease the rotation speed of the blower when the target aeration amount is low. Then, the aeration amount supplied from the aeration unit 7 becomes the target aeration amount calculated by the aeration amount calculation unit 8.

However, in the above-mentioned aeration amount control, when the amount of pollutants in the primary treated water is significantly reduced, the aeration amount in the aerobic treatment tank 3 may become excessive. The aeration amount that can be supplied from the aeration unit 7 includes the minimum aeration amount that is determined by the size and aeration capacity of the blower 6 and the aeration unit 7. If the amount of aeration corresponding to the amount of pollutants is less than the minimum amount of aeration, the amount of aeration should be smaller than the minimum amount of aeration, but due to the equipment, there is no choice but to aerate with the minimum amount of aeration. The amount becomes excessive. If the amount of aeration in the aerobic treatment tank 3 becomes excessive, the water quality may deteriorate due to the disassembly (miniaturization) of the flocs. Therefore, the wastewater treatment system and the wastewater treatment method described below will be adopted.

(First Embodiment)
The wastewater treatment system of this embodiment will be described with reference to the drawings. In the following description, the same reference numerals are given to configurations having the same or similar functions as the wastewater treatment system 100 shown in FIG. Then, the duplicate description of those configurations will be omitted.

As shown in FIG. 2, the wastewater treatment system 200 of the embodiment has the same as the wastewater treatment system 100, that is, the raw water tank 1, the primary treatment tank 2, the aerobic treatment tank 3, the settling tank 4, and the sensor 5. The aeration means 21 and the control device 20 are provided. The control device 20 includes an aeration amount calculation unit 11, an aeration amount control unit 9, and a bypass pump control unit 12. Further, the wastewater treatment system 200 is provided with a water supply line L7 and a bypass pump P2 provided in the water supply line L7 as the water supply means 22.

In the wastewater treatment system 200, the raw water tank 1 and the aerobic treatment tank 3 are connected to each other via the water supply line L7. A bypass pump P2 is provided in the middle of the water supply line L7. The bypass pump P2 is connected to the bypass pump control unit 12.

The control device 20 of the present embodiment determines the target aeration amount based on the processing index value measured by the sensor 5, and when the target aeration amount exceeds the minimum aeration amount of the aeration means 21, the target aeration amount by the aeration means 21 is targeted. When the aeration amount is set and the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount by the aeration means 21 is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank 3 by the water supply means 22. Hereinafter, the control device 20 and the water supply means 22 will be described in detail.

The aeration amount calculation unit 11 of the control device 20 calculates the target aeration amount based on the processing index value measured by the sensor 5. When the target aeration amount exceeds the minimum aeration amount, the aeration amount calculation unit 11 outputs the target aeration amount to the aeration amount control unit 9, and outputs a signal to stop the bypass pump P2 to the bypass pump control unit 12. .. On the other hand, when the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount calculation unit 11 outputs the minimum aeration amount to the aeration amount control unit 9, and sends a signal to the bypass pump control unit 12 to operate the bypass pump P2. Output.

The aeration amount control unit 9 of the control device 20 determines the rotation speed of the blower 6 based on the target aeration amount or the minimum aeration amount output from the aeration amount calculation unit 11, and controls the blower 6 so as to be the rotation speed. To do.

The aeration amount calculation unit 8 and the bypass pump P2 are connected to the bypass pump control unit 12 of the control device 20. The bypass pump control unit 12 controls the bypass pump P2 in response to a signal for stopping or operating the bypass pump P2 output by the aeration amount calculation unit 8. When the bypass pump P2 operates, the raw water is sent to the aerobic treatment tank 3 via the water supply line L7.

The bypass pump P2 of the water supply means 22 sends raw water from the raw water tank 1 to the aerobic treatment tank 3 via the water supply line L7 under the control of the bypass pump control unit 12.

Next, the wastewater treatment method of the present embodiment will be described.
The wastewater treatment method of the present embodiment prefers the stage of treating the raw water sent from the raw water tank 1 in the primary treatment tank 2 and the primary treatment water sent from the primary treatment tank 2 in the aerobic treatment tank 3. It includes a step of air treatment and a step of solid-liquid separation of the secondary water to be treated sent from the aerobic treatment tank 3 in the settling tank 4. Further, in the wastewater treatment method of the present embodiment, the target aeration amount is determined based on the treatment index measured by the sensor 5, and when the target aeration amount exceeds the minimum aeration amount of the aeration means 21, the aeration amount by the aeration means 21 Is set as the target aeration amount, and when the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount by the aeration means 21 is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank 3 by the water supply means 22.

The aeration amount calculation unit 11 calculates the target aeration amount based on the processing index measured by the sensor 5. When the target aeration amount exceeds the minimum aeration amount, the aeration amount calculation unit 11 outputs the target aeration amount to the aeration amount control unit 9, and outputs a signal to stop the bypass pump P2 to the bypass pump control unit 12. .. Then, the aeration amount control unit 9 determines the rotation speed of the blower 6 based on the target aeration amount output from the aeration amount calculation unit 11, and controls the blower 6 so as to be the rotation speed. The bypass pump control unit 12 controls to stop the bypass pump P2.

On the other hand, when the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount calculation unit 11 outputs the minimum aeration amount to the aeration amount control unit 9, and outputs a signal for operating the pump P2 to the bypass pump control unit 12. To do. Then, the aeration amount control unit 9 determines the rotation speed of the blower 6 based on the minimum aeration amount output from the aeration amount calculation unit 11, and controls the blower 6 so as to be the rotation speed. The bypass pump control unit 12 controls the operation of the bypass pump P2.

When the bypass pump P2 operates, raw water having a larger amount of pollutants than the primary treated water is directly sent to the aerobic treatment tank 3 via the water supply line L7. Then, the amount of pollutants in the aerobic treatment tank 3 increases, and the treatment index value measured by the sensor 5 decreases. When the processing index value decreases, the target aeration amount calculated by the aeration amount calculation unit 11 increases, and the target aeration amount exceeds the minimum aeration amount.

According to the above configuration, the amount of pollutants in the aerobic treatment tank 3 is significantly reduced due to seasonal fluctuations and diurnal fluctuations, and the target aeration amount calculated by the aeration amount calculation unit 11 is equal to or less than the minimum aeration amount. In this case, the raw water stored in the raw water tank 1 can be directly sent to the aerobic treatment tank 3. Since the amount of pollutants in the raw water is larger than that in the primary water to be treated, the amount of pollutants in the aerobic treatment tank 3 can be increased by sending the raw water to the aerobic treatment tank 3. As the amount of pollutants in the aerobic treatment tank 3 increases, the treatment index value decreases, and the target aeration amount calculated by the aeration amount calculation unit 11 becomes an aeration amount exceeding the minimum aeration amount. Therefore, even when the amount of pollutants in the primary water to be treated is significantly reduced, the amount of aeration in the aerobic treatment tank 3 does not become excessive, the miniaturization of flocs can be prevented, and the water quality of the supernatant liquid can be prevented. Can be maintained in good condition. Further, since the wastewater treatment can be performed without insufficient the amount of pollutants in the aerobic treatment tank 3, the treatment performance of the aerobic treatment tank 3 can be maintained in a good state. Further, by stopping the operation of the bypass pump P2 when the target aeration amount exceeds the minimum aeration amount, it is possible to prevent the amount of pollutants in the aerobic treatment tank 3 from becoming excessive. Moreover, the power of the blower 6 can be reduced.

(Second Embodiment)
As shown in FIG. 3, the wastewater treatment system 300 of the present embodiment, like the wastewater treatment system 100, has a raw water tank 1, a primary treatment tank 2, an aerobic treatment tank 3, a settling tank 4, and a sensor 5. The aeration means 21 and the control device 30 are provided. The control device 30 includes an aeration amount calculation unit 11, an aeration amount control unit 9, and a distribution device control unit 13. Further, the wastewater treatment system 300 is provided with a second water supply line L9 and a distribution device 14 provided in the second water supply line L9 as the water supply means 23.

In the wastewater treatment system 300, a distribution device 14 is provided in the middle of the first water supply line L8 that connects the raw water tank 1 and the primary treatment tank 2. A second water supply line L9 is connected to the distribution device 14. The second water supply line L9 is connected to the aerobic treatment tank 3. The distribution device 14 can supply raw water to the primary treatment tank 2 and the aerobic treatment tank 3 via the first water supply line L8 and the second water supply line L9. Further, the distribution device 14 is connected to the distribution device control unit 13.

The control device 30 of the present embodiment determines the target aeration amount based on the processing index value measured by the sensor 5, and when the target aeration amount exceeds the minimum aeration amount of the aeration means 21, the target aeration amount by the aeration means 21 is targeted. When the aeration amount is set and the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount by the aeration means 21 is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank 3 by the water supply means 23. The control device 30 and the water supply means 23 will be described in detail below.

The aeration amount calculation unit 11 of the control device 30 calculates the target aeration amount based on the processing index value measured by the sensor 5. When the target aeration amount exceeds the minimum aeration amount, the aeration amount calculation unit 11 outputs the target aeration amount to the aeration amount control unit 9, and outputs a signal to stop the distribution device 14 to the distribution device control unit 13. .. On the other hand, when the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount calculation unit 11 outputs the minimum aeration amount to the aeration amount control unit 9, and sends a signal to the distribution device control unit 13 to operate the distribution device 14. Output.

The aeration amount calculation unit 8 and the distribution device 14 are connected to the distribution device control unit 13 of the control device 30. The distribution device control unit 13 controls the distribution device 14 according to a signal for stopping or operating the distribution device 14 output by the aeration amount calculation unit 8. When the distribution device 14 operates, raw water is sent to the primary treatment tank 2 and the aerobic treatment tank 3 via the first water supply line L8 and the second water supply line L9.

The distribution device 14 of the water supply means 23 transfers raw water to the primary treatment tank 2 via the first water supply line L8 under the control of the distribution device control unit 13, or the first water supply lines L8 and the second. Raw water is sent to the primary treatment tank 2 and the aerobic treatment tank 3 via the water supply line L9.

Next, the wastewater treatment method of the present embodiment will be described.
The wastewater treatment method of the present embodiment prefers the stage of treating the raw water sent from the raw water tank 1 in the primary treatment tank 2 and the primary treatment water sent from the primary treatment tank 2 in the aerobic treatment tank 3. It includes a step of air treatment and a step of solid-liquid separation of the secondary water to be treated sent from the aerobic treatment tank 3 in the settling tank 4. Further, in the wastewater treatment method of the present embodiment, the target aeration amount is determined based on the treatment index value measured by the sensor 5, and when the target aeration amount exceeds the minimum aeration amount of the aeration means 21, the aeration amount by the aeration means 21 When the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount by the aeration means 21 is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank 3 by the water supply means 23.

The aeration amount calculation unit 11 calculates the target aeration amount based on the processing index value measured by the sensor 5. When the target aeration amount exceeds the minimum aeration amount, the aeration amount calculation unit 11 outputs the target aeration amount to the aeration amount control unit 9, and outputs a signal to stop the distribution device 14 to the distribution device control unit 13. .. Then, the aeration amount control unit 9 determines the rotation speed of the blower 6 based on the target aeration amount output from the aeration amount calculation unit 11, and controls the blower 6 so as to be the rotation speed. The distribution device control unit 13 stops the distribution device 14.

On the other hand, when the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount calculation unit 11 outputs the minimum aeration amount to the aeration amount control unit 9, and sends a signal to the distribution device control unit 13 to operate the distribution device 14. Output. Then, the aeration amount control unit 9 determines the rotation speed of the blower 6 based on the minimum aeration amount output from the aeration amount calculation unit 11, and controls the blower 6 so as to be the rotation speed. The distribution device control unit 13 controls the operation of the distribution device 14.

When the distribution device 14 operates, the raw water that has been sent from the raw water tank 1 to the primary treatment tank 2 via the first water supply line L8 is distributed to the aerobic treatment tank 3 via the second water supply line L9. When the raw water is directly sent from the raw water tank 1 to the aerobic treatment tank 3, the amount of pollutants in the aerobic treatment tank 3 increases, and the treatment index value measured by the sensor 5 decreases. When the processing index value decreases, the target aeration amount calculated by the aeration amount calculation unit 11 increases, and the target aeration amount exceeds the minimum aeration amount.

According to the above configuration, when the amount of pollutants in the aerobic treatment tank 3 is significantly reduced and the target aeration amount calculated by the aeration amount calculation unit 11 is equal to or less than the minimum aeration amount, the raw water tank 1 is used. The stored raw water can be directly sent to the aerobic treatment tank 3. When the raw water is sent to the aerobic treatment tank 3, the amount of pollutants in the aerobic treatment tank 3 increases and the treatment index value decreases, so that the target aeration amount calculated by the aeration amount calculation unit 11 is the minimum. The amount of aeration exceeds. Therefore, even when the amount of pollutants in the primary water to be treated is significantly reduced, the amount of aeration in the aerobic treatment tank 3 does not become excessive, the miniaturization of flocs can be prevented, and the water quality of the supernatant liquid can be prevented. Can be maintained in good condition. Further, since the wastewater treatment can be performed without insufficient the amount of pollutants in the aerobic treatment tank 3, the treatment performance of the aerobic treatment tank 3 can be maintained in a good state. Further, even if the raw water stored in the raw water tank 1 is directly sent to the aerobic treatment tank 3, the amount of raw water flowing out from the raw water tank 1 can be kept constant. Therefore, the amount of wastewater flowing into the aerobic treatment tank 3 is maintained constant, and the residence time of the primary water to be treated and the raw water in the aerobic treatment tank 3 can be secured. As a result, the aerobic treatment in the aerobic treatment tank 3 is sufficiently performed, and the deterioration of the water quality of the secondary water to be treated can be prevented.

In the present embodiment, the shape of the distribution device 14 may be a shape like a three-way valve or a shape like a drainage box.

Further, in the above-described embodiment, a step of treating the water to be treated in a separate tank may be included between the step of treating the water to be treated in the primary treatment tank and the step of treating the water in the aerobic treatment tank.

Further, in the above-described embodiment, the sensor 5 for measuring the treatment index value of the primary water to be treated in the aerobic treatment tank 3 is a dissolved oxygen concentration meter (DO meter) for measuring the dissolved oxygen concentration in water or in water. A redox potential meter (ORP meter) that measures the redox potential may be used.

Further, in the above-described embodiment, the method of controlling the aeration amount supplied from the aeration unit 7 by increasing or decreasing the rotation speed of the blower 6 has been described, but the air volume adjusting valve provided in the middle of the air supply line L6 has been described. The amount of aeration may be controlled by adjusting.

According to at least one embodiment described above, a sensor for measuring the treatment index value of the primary treated water stored in the aerobic treatment tank and the raw water flowing out of the raw water tank are sent to the aerobic treatment tank. The target aeration amount is determined based on the water supply means and the processing index value measured by the sensor, and if the target aeration amount exceeds the minimum aeration amount of the aeration means, the aeration amount by the aeration means is set as the target aeration amount, and the target aeration amount is set. When is less than or equal to the minimum aeration amount, the treated water is provided with a control device that maintains the aeration amount by the aeration means at the minimum aeration amount and supplies the raw water to the aerobic treatment tank by the water supply means. It is possible to provide a wastewater treatment system and a wastewater treatment method capable of maintaining the water quality in a good state.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

100, 200, 300 ... Wastewater treatment system, 1 ... Raw water tank, 2 ... Primary treatment tank, 3 ... Aerobic treatment tank, 4 ... Sedimentation tank, 5 ... Sensor, 6 ... Blower, 7 ... Aeration section, 8, 11 ... Aeration amount calculation unit, 9 ... Aeration amount control unit, 10, 20, 30 ... Control device, 12 ... Bypass pump control unit, 13 ... Distributor control unit, 14 ... Distributor, 21 ... Aeration means, 22, 23 ... Water supply Means, L1 ... raw water supply line, L6 ... air supply line, L7 ... water supply line, L8 ... first water supply line, L9 ... second water supply line, P1 ... pump, P2 ... bypass pump

Claims (8)

Raw water tank and
At least one primary treatment tank for treating the raw water flowing out of this raw water tank,
An aerobic treatment tank that aerobically treats the primary treatment water discharged from this primary treatment tank with microorganisms,
An aeration means for aerating the primary water to be treated stored in the aerobic treatment tank, and
A sensor the reduced with increasing pollutant amount has been the primary treated in water reserved in aerobic treatment tank, to measure the processing index value which increases with decreasing the contaminants amount,
A water supply means for sending the raw water flowing out of the raw water tank to the aerobic treatment tank, and
The target aeration amount is determined based on the treatment index value of the primary treated water measured by the sensor, and when the target aeration amount exceeds the minimum aeration amount of the aeration means, the aeration amount in the aeration means is set to the target aeration. When the target aeration amount is equal to or less than the minimum aeration amount, the aeration amount in the aeration means is maintained at the minimum aeration amount, and the raw water is supplied to the aerobic treatment tank by the water supply means. A wastewater treatment system equipped with a control device. The water supply means includes a water supply line from the raw water tank to the aerobic treatment tank, and a pump controlled by the control device to send the raw water to the aerobic treatment tank via the water supply line. The wastewater treatment system according to claim 1. A first water supply line for flowing the raw water is provided between the raw water tank and the primary treatment tank.
The water supply means is installed at a second water supply line that branches from the first water supply line and reaches the aerobic treatment tank to the aerobic treatment tank, and a connection portion between the first water supply line and the second water supply line to control the control. The wastewater treatment system according to claim 1, further comprising a distribution device controlled by the device. The wastewater treatment system according to any one of claims 1 to 3, wherein the treatment index value is a dissolved oxygen concentration or a redox potential. Raw water tank and
At least one primary treatment tank for treating the raw water flowing out of the raw water tank, and
An aerobic treatment tank that aerobically treats the primary treatment water flowing out of the primary treatment tank with microorganisms,
An aeration means for aerating the primary water to be treated stored in the aerobic treatment tank, and
A sensor the reduced with increasing pollutant amount has been the primary treated in water reserved in aerobic treatment tank, to measure the processing index value which increases with decreasing the contaminants amount,
A water supply means for sending the raw water flowing out of the raw water tank to the aerobic treatment tank, and
It is a wastewater treatment method by a wastewater treatment system equipped with
The target aeration amount is determined based on the processing index value measured by the sensor, and when the target aeration amount exceeds the minimum aeration amount of the aeration means, the aeration amount in the aeration means is set as the target aeration amount, and the target aeration amount is used. When the amount is equal to or less than the minimum aeration amount, a wastewater treatment method in which the aeration amount in the aeration means is maintained at the minimum aeration amount and the raw water is supplied to the aerobic treatment tank by the water supply means. The water supply means includes a water supply line from the raw water tank to the aerobic treatment tank, and a pump for supplying the raw water to the aerobic treatment tank via the water supply line.
The wastewater treatment method according to claim 5 , wherein the raw water is supplied to the aerobic treatment tank by controlling the pump. A first water supply line for flowing the raw water is provided between the raw water tank and the primary treatment tank.
The water supply means includes a second water supply line that branches from the first water supply line and reaches the aerobic treatment tank, and a distribution portion installed at a connection portion between the first water supply line and the second water supply line. Equipped with equipment,
The wastewater treatment method according to claim 5 , wherein the raw water is supplied to the primary treatment tank and the aerobic treatment tank by controlling the distribution device. The wastewater treatment method according to any one of claims 5 to 7, wherein the treatment index value is a dissolved oxygen concentration or a redox potential.

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