JP7241608B2 - Wastewater treatment system and wastewater treatment method - Google Patents

Description

The present application relates to a wastewater treatment system and a wastewater treatment method.

As a method for treating wastewater containing organic matter, a treatment method using microorganisms such as a standard activated sludge method is widely used. In a treatment method using microorganisms, a large amount of excess sludge containing activated sludge due to the growth of microorganisms and other suspended solids may be generated during the treatment of wastewater.

Since surplus sludge is sludge that is unnecessary for water treatment, it is discharged out of the wastewater treatment system, incinerated as industrial waste, and landfilled. Disposal of such excess sludge requires a great deal of energy, cost, and new land, and thus reduction in the amount of excess sludge generated is desired.

As one method for reducing the amount of excess sludge generated, sludge volume reduction treatment is known, in which ozone is used to reduce the volume of excess sludge. Specifically, excess sludge in which microorganisms and the like have gathered is decomposed by supplying ozone or high-concentration ozone. In such biological treatment, it is necessary to send a large amount of air into the biological treatment tank. In particular, when ozonated sludge is returned to the biological treatment tank, it becomes necessary to increase the amount of air for aeration due to the increase in the load of organic matter. As a method for controlling such an aeration air volume, there is known a technique of controlling by using the measurement results of the activity of microorganisms in the biological treatment tank, as disclosed in Patent Document 1, for example.

JP 2013-226536 A

As described in Patent Document 1, when the measurement result of the microbial activity in the biological treatment tank is used to control the aeration air volume, a device is required to automatically measure the microbial activity and transmit a signal to the control device. As a result, there was a problem that this initial cost was added to the running cost due to the increase in the aeration air volume.

In addition, in the technique described in Patent Document 1, since the control of the aeration air volume is started after confirming the measurement result of the microbial activity, there is a possibility that the quality of the treated water has already been affected. In some cases, there was a problem that effective aeration air volume control could not be achieved.

The present application was made to solve the above problems, and in the volume reduction treatment of excess sludge using ozone, the aeration air volume of the biological treatment tank can be reduced without using a water quality sensor such as a microbial activity meter. It is an object to obtain a controlled wastewater treatment system and a wastewater treatment method.

The wastewater treatment system disclosed in the present application comprises:
a biological treatment tank for biologically treating organic wastewater under aerobic conditions to produce sludge-containing treated water containing sludge;
an ozone reaction unit that ozonizes the sludge-containing treated water generated in the biological treatment tank and then returns it to the biological treatment tank;
an ozone generator that generates ozone gas from the raw material supplied from the raw material supply device and supplies the ozone gas to the ozone reaction section;
an ozone control device that is integrated with or installed with the ozone generator and that controls the ozone treatment;
an ozonation detection means connected to an ozone control device for detecting an ozonation start signal output from the ozonization control device when ozonation by the ozonization device is started and for outputting an ozonation start detection signal;
aeration air volume control means for controlling the air volume of aeration into the biological treatment tank based on the ozonation start detection signal .

According to the wastewater treatment system disclosed in the present application, it is possible to increase the aeration air volume without separately preparing a sensor for measuring the activity of microorganisms, so that the initial cost and running cost can be reduced more than before. can be done.

1 is a schematic diagram showing the configuration of a wastewater treatment system according to Embodiment 1; FIG. 2 is a diagram showing an example of hardware configuration of an ozonation control device of the wastewater treatment system according to Embodiment 1; FIG. 4 is a diagram showing an operation outline of a wastewater treatment process of the wastewater treatment system according to Embodiment 1; FIG. FIG. 4 is a diagram showing the operation of the wastewater treatment system according to Embodiment 1 when ozone is injected into sludge; FIG. 5 is a diagram showing the operation of air volume control of the aeration air volume of the wastewater treatment system according to Embodiment 1; FIG. 10 is a diagram showing a treatment time ratio of the wastewater treatment system according to Embodiment 2; FIG. 10 is a schematic diagram showing the configuration of a wastewater treatment system according to Embodiment 3;

Hereinafter, embodiments of the wastewater treatment system and the wastewater treatment method disclosed by the present application will be described in detail with reference to the drawings. The same reference numerals are assigned to the same contents and corresponding parts, and detailed description thereof will be omitted. In the following embodiments as well, redundant descriptions of the configurations denoted by the same reference numerals will be omitted. In addition, the embodiment shown below is an example, and this application is not limited by these embodiments.

Embodiment 1.
FIG. 1 is a schematic diagram showing the configuration of a wastewater treatment system according to Embodiment 1. FIG. The wastewater treatment system includes a biological treatment tank 1 having an aerobic tank or an aeration tank, an air diffuser 2, a solid-liquid separation unit 18, an ozone reaction unit 8, a raw material supply device 12, an ozone generator 10, an ozone treatment detection means 14, Aeration air volume control means 15 and the like are provided. In the figure, solid-line arrows indicate the flow of treated water, ozone gas, or their pipes, and dashed-line arrows indicate the signal flow.

The air diffuser 2 is connected to the air supply device 3 and installed mainly at the bottom of the biological treatment tank 1 . As a result, the air discharged from the air supply device 3 is supplied into the biological treatment tank 1, and the biological treatment tank 1 is kept under an aerobic condition. A blower, a compressor, or the like is used as the air supply device 3 depending on the required air supply amount.

Activated sludge mainly composed of aggregates of aerobic microorganisms is stored in the biological treatment tank 1. Sludge containing activated sludge is mixed with wastewater 4 inflow from the outside under aerobic conditions. Contained treated water 17 is produced.

The biological treatment tank 1 is pipe-connected so that the sludge-containing treated water 17 flows out to the solid-liquid separation section 18 . The sludge-containing treated water 17 produced in the biological treatment tank 1 is separated into treated water after separation treatment and thickened sludge in a solid-liquid separation unit 18 represented by a terminal sedimentation tank or a membrane separation tank. The thickened sludge return pipe 19 is connected to the solid-liquid separation unit 18 and the biological treatment tank 1, and configured to return the separated thickened sludge to the biological treatment tank 1 via a pump or the like (not shown). are doing.

When the solid-liquid separation unit 18 is in the form of a membrane separation tank, it is not limited to the external tank configuration shown in the figure depending on the configuration of the membrane module used in the membrane separation activated sludge process, and the internal tank configuration is also possible. It is possible.

The ozone reaction part 8 is a part where the sludge-containing treated water 17 withdrawn from the biological treatment tank 1 is reacted by ozone treatment. The ozone reaction section 8 is connected to the biological treatment tank 1 by a sludge extraction pipe 6 . A sludge extraction pump 5 is installed in the sludge extraction pipe 6 . The size of the sludge extraction pump 5 is determined from the amount of excess sludge generated or the amount of sludge extracted calculated from the number of times of sludge treatment per day, etc., and the pump head caused by the installation position of the pump or pressure loss in piping.

After the sludge-containing treated water 17 undergoes the ozone reaction in the ozone reaction section 8 , it is returned to the biological treatment tank 1 through the sludge return pipe 7 connected to the lower portion of the ozone reaction section 8 . A pump or the like may be used for the return, but if the ozone reaction section 8 is arranged in the upper part of the biological treatment tank 1, it is also possible to return by gravity. The sludge-containing treated water 17 in the biological treatment tank 1 can be continuously transferred to the ozone reaction section 8 by the sludge extraction pump 5 . The object to be transferred to the ozone reaction unit 8 by the sludge extraction pump 5 is not limited to the sludge-containing treated water 17 in the biological reaction tank 1, but it is also possible to use the concentrated sludge separated by the solid-liquid separation unit 18. be. One end of an ozone gas injection pipe 9 is connected to the side surface of the ozone reaction section 8 , and the other end is connected to the outlet of the ozone generator 10 .

The ozone generator 10 generates ozonized oxygen (hereinafter referred to as ozone gas) at a necessary flow rate and concentration to be supplied to the ozone reaction section 8 through the ozone gas injection pipe 9 . The ozone generator 10 is connected to a raw material supply device 12 and a cooling device (not shown) through a raw material gas supply pipe 11 . The source gas supply pipe 11 supplies the ozone gas source to the ozone generator 10 . The cooling device also cools the ozone generator 10 .

The raw material of the ozone gas supplied from the raw material supply device 12 to the ozone generator 10 is not particularly limited. For example, liquid oxygen or oxygen generated by PSA (Pressure Swing Adsorption) or VSA (Vacuum Swing Adsorption) can be used. If necessary, an additive gas supply unit (not shown) may be provided for adding 0.05 to 0.5% nitrogen, air, etc. according to the oxygen flow rate to be supplied in order to maintain the ozone generation efficiency.

The cooling device (not shown) includes a refrigerant circulation pump that circulates a cooling medium for cooling the ozone generator 10, and a cooler that absorbs the heat generated by the ozone generator 10 and cools the cooling medium whose temperature has risen. Prepare. A heat exchanger, chiller, refrigerator, or the like can be used as the cooler. As the cooling medium, in addition to tap water, water mixed with ion-exchanged water, antifreeze, scale remover, corrosion inhibitor, or the like can be used.

Although FIG. 1 does not show a specific ozone gas injection method, the wastewater treatment system according to the present application may use any ozone gas injection method such as an ejector method, an aeration method, or a mechanical stirring method.

Although the concentration of ozone generated from the ozone generator 10 is not particularly limited, it is necessary to improve the biodegradability of the sludge in the sludge-containing treated water 17 to promote the reduction of excess sludge in the biological treatment tank 1, and the current ozone Considering the ozone concentration that can be generated by the generator 10, it is preferably 100 mg/L or more and 400 mg/L or less.

The ozone gas generated by the ozone generator 10 is injected into the sludge-containing treated water 17 in the ozone reaction section 8 through the ozone gas injection pipe 9 .

The ozonation control device 20 is a control device such as a PLC (Programmable Logic Controller) that is integrated with or attached to the ozone generator 10, and is mounted on, for example, a control panel (not shown) that controls the entire wastewater treatment system. may The ozonation control device 20 is connected to the ozonation detection means 14 .

An example of an ozonation control device 20 is shown in FIG. It comprises a processor 100 and a storage device 200. Although not shown, the storage device comprises a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Also, an auxiliary storage device such as a hard disk may be provided instead of the flash memory. The processor 100 executes a program input from the storage device 200 to control the ozone treatment described below. In this case, the program is input from the auxiliary storage device to the processor 100 via the volatile storage device. Further, the processor 100 may output data such as calculation results to the volatile storage device of the storage device 200, or may store the data in the auxiliary storage device via the volatile storage device. Note that the program can be changed externally.

The ozone treatment detection means 14 detects an ozone treatment start signal 13a and an ozone treatment end signal 13b including information regarding the start or end of the ozone treatment from the connected ozone treatment control device 20 . This ozone treatment start signal 13a or ozone treatment end signal 13b may be, for example, a PLC timing signal. Further, the ozonation detection means 14 can use the signal detection function of PLC. Based on the detected ozone treatment start signal 13a and ozone treatment end signal 13b, an ozone treatment start detection signal 14a or an ozone treatment end detection signal 14b is sent to the aeration air volume control means 15. FIG.

The aeration air volume control means 15 is connected to the ozone treatment detection means 14, starts the ozone treatment based on the ozone treatment start detection signal 14a, and controls the aeration air volume in the biological treatment tank 1 based on the aeration air volume control signal 16a. . For example, the aeration air volume control means 15 is connected to the air supply device 3 and controls the aeration air volume according to the amount of air supplied to the biological treatment tank 1 .

(1) Next, an overview of the operation of the wastewater treatment process of the wastewater treatment system of the present embodiment will be described with reference to FIG. First, the wastewater 4 flows into the biological treatment tank 1, and the activated sludge mainly composed of aggregates of aerobic microorganisms stored in the tank merges with the wastewater 4 (step S100). At that time, the air diffuser 2 supplies the air discharged from the air supply device 3 into the biological treatment tank 1, and the biological treatment tank 1 is aerobic in order to increase the microbial activity of the aerobic microorganisms in the activated sludge. conditions (step S101).

Wastewater 4 flowing into the biological treatment tank 1 is mixed with activated sludge under aerobic conditions, and organic matter is adsorbed and biodegraded by aerobic microorganisms to produce sludge-containing treated water 17 containing activated sludge. is generated, and the waste water 4 is purified (step S102). The amount of air discharged from the air supply device 3, that is, the amount of aeration air, is the numerical value of the organic matter load, which is the ratio of organic matter contained in the inflowing wastewater 4 to the amount of activated sludge in the biological treatment tank 1, or the temperature. Adjustments may be necessary if conditions change.

The generated sludge-containing treated water 17 is discharged to the solid-liquid separation section 18 (step S103). The solid-liquid separation unit 18 separates the sludge-containing treated water 17 into treated water (not shown) after separation treatment and concentrated sludge. (Step S104) The separated thickened sludge is returned to the biological treatment tank 1 by a pump or the like through the thickened sludge return pipe 19 (Step S105).

(2) Next, the operation of injecting ozone into sludge for satisfying the sludge volume reduction effect in the wastewater treatment system of Embodiment 1 will be described with reference to FIG.
First, the sludge-containing treated water 17 is drawn from the biological treatment tank 1 or the solid-liquid separation section 18 to the ozone reaction section 8 through the sludge drawing pipe 6 using the sludge drawing pump 5 (step S200).

Next, the raw material gas is supplied from the raw material supply device 12 to the ozone generator 10 through the raw material gas supply pipe 11 (step S201). The ozone gas generated by supplying the raw material gas is supplied to the ozone reaction section 8 through the ozone gas injection pipe 9 (step S202). As a result, ozone gas is injected into the sludge-containing treated water 17 stored in the ozone reaction unit 8 to decompose persistent organic substances such as activated sludge microorganisms in the sludge-containing treated water 17 (step S203).

The ozone-treated sludge is returned to the biological treatment tank 1 through the sludge return pipe 7 (step S204). As a result, the decomposition-treated persistent organic matter contained in the ozonated sludge returned to the biological treatment tank 1 is biodegraded again by the activated sludge (that is, aerobic microorganisms) in the biological treatment tank 1. Volume reduction of excess sludge is carried out.

Here, the return of the ozonized sludge to the biological treatment tank 1 increases the organic matter load, which may make it necessary to increase the amount of aeration air discharged from the air supply device 3 . However, this does not apply if the amount of aeration air discharged from the air supply device 3 originally includes a sufficient margin to cover the increase in the required air amount.

(3) Next, the operation of performing air volume control, such as increasing the volume of aerated air discharged from the air supply device 3 or restoring the operating air volume after increasing, will be described with reference to FIG.
When the ozone treatment is started by the ozone generator 10, the ozone treatment start signal 13a, which is a timing signal, is sent from the ozone treatment control device 20 to the ozone treatment detection means 14 (step S301). The ozonation detection means 14 detects the ozonation start signal 13a. The ozone treatment detection means 14 receives the detection of the ozone treatment start signal 13a and sends an ozone treatment start detection signal 14a for starting the ozone treatment to the aeration air volume control means 15 (step S302).

The aeration air volume control means 15 transmits an aeration air volume control signal 16a to the air supply device 3 based on the ozone treatment start detection signal 14a (step S303). The aeration air volume control means 15 controls the aeration air volume in the biological treatment tank 1 by increasing the aeration air volume of the air supply device 3 (step S304). The amount of increase in the required amount of aeration air can be appropriately set according to the dissolution efficiency of oxygen in the sludge-containing treated water of the biological treatment tank 1 by the air supply device 3, the water temperature in the biological treatment tank 1, and the like. However, it is preferable to preliminarily calculate the minimum necessary amount of increase by estimating the increased organic matter load from the amount of sludge to be treated or the amount of ozone to be injected.

In this manner, when the aeration air volume control means 15 receives the ozone treatment start detection signal 14a from the ozone treatment detection means 14, control is performed to increase the aeration air volume.
As a result, it is possible to efficiently increase only the minimum necessary amount of aeration air by using the configuration of the control device attached to the device without separately preparing a sensor for measuring the activity of microorganisms. Become. As a result, the initial cost and running cost can be reduced more than before.

In addition, since control can be started with the start of ozonation as a trigger, unlike the case after confirming the measurement results of microbial activity, the aeration air volume can be increased before water quality is affected. Thereby, it is possible to more effectively suppress the increase in dissolved organic oxygen concentration (DOC concentration) in the treated water.

Further, the aeration air volume control means 15 may start control to increase the aeration air volume a certain time before the timing of starting the ozonation. This is because after increasing the aeration air flow rate, the time required for the increased amount of oxygen to dissolve and become dissolved oxygen may be delayed depending on conditions such as the size of the bubble diameter. be. The range of this fixed time is not particularly limited, and may be appropriately set according to the time required for the amount of oxygen increased by the aeration air volume to become dissolved oxygen in each treatment plant. It should be noted that the generation of the timing signal a certain time before the start of the ozone treatment may be programmed in the ozone treatment control device 20 in advance.

Further, the aeration air volume control means 15 may perform control to increase the aeration air volume after a certain period of time has elapsed after the ozonation detection means 14 has detected the information regarding the start of the ozonation. This is to take into consideration the time required from the start of the ozonation until the ozonized sludge reaches the biological treatment tank 1 by injecting ozone and performing the ozonation. For example, when the ozonized sludge is returned to a pond other than the aerobic tank and then returned to the biological treatment tank 1 via the pond, a residence time for movement may occur. Since the residence time differs from treatment plant to treatment plant, the range of the fixed time after the detection by the ozonation detection means 14 until the aeration air volume is increased is appropriate for each treatment plant depending on the place where the ozonized sludge is returned. , and is not particularly limited. As a result, the aeration air volume can be increased after the ozonized sludge reaches the biological treatment tank 1, enabling more effective control.

Further, the aeration air volume control means 15 increases the aeration air volume based on the ozone treatment start signal 13a, detects the information regarding the end of the ozone treatment detected by the ozone treatment detection means 14, that is, the ozone treatment end signal 13b, and detects the detected end signal 13b. Based on the ozone treatment end detection signal 14b indicating that the aeration air volume control signal 16b is transmitted to the air supply device 3, it is also possible to perform control to restore the aeration air volume (steps S305 to S307 in FIG. 5). . As a result, the amount of aeration air does not continue to increase excessively after the end of the ozonation, and the amount of aeration air can be controlled more effectively.

Furthermore, after the ozonization detection means 14 detects the ozone treatment end signal 13b, the aeration air volume may be restored by sending the ozone treatment end detection signal 14b to the aeration air volume control means 15 after a certain period of time has elapsed. . As with the control to increase the aeration air volume before and after the timing of the start of ozonation described above, by considering the time difference and residence time, the aeration air volume can be effectively adjusted so that the total ozonation time and the aeration time are the same. can be controlled and the impact on the water quality of the treated water can be further reduced.
In addition, when it is found by tests that the time required to increase the aeration air volume required to suppress the increase in the organic matter load due to ozonation sludge is longer than the interval from the start to the end of the injection of ozone, ozonation should be carried out. Such control is effective because the aeration time must be longer than the total time.
Similar to the time until the aeration air volume is increased, the amount of oxygen corresponding to the increase in the aeration air volume at each treatment plant is also within the certain time range from the detection by the ozone treatment detection means 14 until the aeration air volume is restored. It may be appropriately set according to the time to become dissolved oxygen, and is not particularly limited.

Embodiment 2.
Next, a wastewater treatment system according to Embodiment 2 will be described with reference to FIG. FIG. 6 is a diagram showing the treatment time ratio of the wastewater treatment system according to the second embodiment. The basic configuration and operation of the wastewater treatment system according to the second embodiment are the same as those of the first embodiment. However, while Embodiment 1 does not specifically specify the form of ozone treatment such as continuous or intermittent, Embodiment 2 differs in that the form of ozone treatment is specified as intermittent ozone treatment. . That is, in the ozone reaction unit 8, the treatment mode of injecting ozone gas into the sludge-containing treated water 17 is intermittent ozone treatment in which the ozone gas is injected at regular time intervals.

Organic matter biodegraded in ozonation is more biodegradable than general organic matter. Therefore, when the sludge containing the ozone-treated organic matter is returned to the biological treatment tank 1, the load of the organic matter temporarily increases, and it is necessary to increase the aeration air volume. However, by stopping the ozonation by intermittent ozonation and providing a period during which the ozonized sludge is not returned, the water quality is less likely to be affected even if the aeration air volume is restored without constantly increasing the aeration air volume. The inventors have found.

In the intermittent ozone treatment, the ratio of the ozone treatment time (OP) to the cycle time (CP) of the intermittent ozone treatment, that is, the treatment time ratio (OP/CP), is set within a certain range, for example, about 0.05 to 0.2. It may be controlled within the range. As a result, ozone gas is injected into the sludge-containing treated water 17 withdrawn from the biological treatment tank 1 in an intermittent ozone treatment mode. As a result, it is possible to set a period (short time) to reduce the sludge volume and a period (long time) to stop the ozone treatment and restore the activity of the sludge. It is possible to suppress the increase in the DOC concentration in the water, and for the reason described above, there is the effect of suppressing the increase in the amount of aeration air.

Embodiment 3.
Next, a sewage treatment system according to Embodiment 3 will be described with reference to FIG. The basic configuration and operation of the sewage treatment system according to Embodiment 3 are the same as those of Embodiment 1, except that an ozone concentrator 21 is installed in the middle of the ozone gas injection pipe 9 .

The ozone gas generated by the ozone generator 10 is adsorbed and concentrated by the ozone concentrator 21 . The concentrated high-concentration ozone gas is injected into the ozone reaction section 8 and, like the first embodiment, hardly decomposes activated sludge microorganisms in the sludge-containing treated water 17 withdrawn from the biological treatment tank 1 or the solid-liquid separation section 18. decompose organic matter.

Focusing on the relationship between the concentration of ozone gas to be injected into the sludge-containing treated water 17 and the necessary injection amount of ozone, that is, the convergence value of the injection amount of ozone, an experiment was conducted. The inventors of the present application have confirmed that the convergence value of is smaller.

Therefore, in the third embodiment, the high-concentration ozone generated by the ozone concentrator 21 of about 400 mg/L or more and up to about 2000 mg/L at the maximum is brought into contact with the optimum amount of ozone gas. The effect of improving processing efficiency can be expected. As a result, the amount of ozone to be supplied can be small, and the initial cost including the ozone generator 10 and the running cost of ozone generation and injection can be further reduced.

In addition, the oxygen gas not adsorbed in the process of adsorbing and concentrating ozone gas in the ozone concentrator 21 may be returned to the ozone generator 10 through an oxygen gas return pipe (not shown) and reused in the ozone generator 10 . is also possible, and the running cost can be further reduced.

While this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may not apply to particular embodiments. can be applied to the embodiments singly or in various combinations.
Accordingly, numerous variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, modification, addition or omission of at least one component, extraction of at least one component, and combination with components of other embodiments shall be included.

1: biological treatment tank, 2: air diffuser, 3: air supply device, 4: waste water, 5: sludge extraction pump, 6: sludge extraction pipe, 7: sludge return pipe, 8: ozone reaction part, 9: ozone gas injection Piping 10: Ozone generator 11: Raw material gas supply pipe 12: Raw material supply device 13a: Ozone treatment start signal 13b: Ozone treatment end signal 14: Ozone treatment detection means 14a: Ozone treatment start detection signal 14b: Ozone treatment end detection signal, 15: Aeration air volume control means, 16a, 16b: Aeration air volume control signal, 17: Sludge-containing treated water, 18: Solid-liquid separator, 19: Concentrated sludge return pipe, 20: Ozone treatment control Apparatus, 21: Ozone Concentrator

Claims (12)

a biological treatment tank for biologically treating organic wastewater under aerobic conditions to produce sludge-containing treated water containing sludge;
an ozone reaction unit that performs ozone treatment on the sludge-containing treated water generated in the biological treatment tank and then returns it to the biological treatment tank;
an ozone generator that generates ozone gas from raw materials supplied from a raw material supply device and supplies the ozone gas to the ozone reaction unit;
an ozone control device integrated with or in parallel with the ozone generator for controlling the ozone treatment;
ozone treatment detection means connected to the ozone control device, detecting an ozone treatment start signal output from the ozone control device when the ozone treatment by the ozone generator is started, and outputting an ozone treatment start detection signal;
aeration air volume control means for controlling an aeration air volume into the biological treatment tank based on the ozonation start detection signal . 2. The wastewater treatment system according to claim 1, wherein said aeration air volume control means performs control to increase the aeration air volume based on said ozonation detection means detecting said ozonation start signal . 2. The wastewater treatment system according to claim 1, wherein the aeration air volume control means increases the aeration air volume after a certain period of time has elapsed after the ozone treatment start signal is detected by the ozone treatment detection means. 4. The wastewater treatment system according to any one of claims 1 to 3, wherein said ozonation detection means detects an ozonation end signal in addition to said ozonation start signal . 5. The aeration air volume control means according to claim 4, wherein the aeration air volume is increased based on the ozonation start detection signal , and controlled to restore the aeration air volume based on the ozonation end detection signal. Wastewater treatment system. 6. Wastewater according to claim 4 or 5, wherein said aeration air volume control means performs control to restore the aeration air volume after a predetermined period of time has elapsed after said ozone treatment end signal has been detected by said ozone treatment detection means. processing system. The wastewater treatment system according to any one of claims 1 to 6, wherein the ozonation is intermittent ozonation. 8. The wastewater treatment system according to claim 7, wherein in the intermittent ozonation, the ratio of the ozonation time to the cycle time of the ozonation is controlled within a certain range. 2. The wastewater treatment system according to claim 1 , wherein said aeration air volume control means performs control to increase the aeration air volume a predetermined time before said ozone treatment start signal . 10. The wastewater treatment system according to any one of claims 1 to 9 , further comprising a concentrator for concentrating the ozone gas to generate high-concentration ozone, and supplying the high-concentration ozone to the ozone reaction section. . Ozone treatment is started by injecting ozone gas generated by an ozone generator into sludge-containing treated water extracted from a biological treatment tank in which the aeration air volume is controlled, and wastewater returned to the biological treatment tank after the ozone treatment is completed. In the treatment method, the ozone treatment detection means detects an ozone treatment start signal output from an ozone control device integrated with or provided with the ozone generator when the ozone treatment of the ozone generator is started, and the ozone treatment is output. A wastewater treatment method, characterized in that the amount of aeration air is increased based on a start detection signal . 12. The wastewater treatment method according to claim 11 , wherein the ozonation detection means detects an ozonation end signal , and restores the increased aeration air volume based on the outputted ozonation end detection signal .

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