JP7262673B2 - Ozonated water production device, water treatment device, and ozone water production method - Google Patents

Description

The present disclosure relates to an ozonated water production apparatus, a water treatment apparatus, and an ozonated water production method for producing ozonated water used for removing organic matter.

As a method for treating wastewater containing organic matter, the membrane separation activated sludge method is known, in which the organic matter in the water to be treated is decomposed by biological treatment, and clear treated water is obtained by solid-liquid separation using a separation membrane, also called a filtration membrane. there is Contaminants including sludge, suspended solids, microorganisms and metabolites of microorganisms, etc. adhere to or adhere to the membrane surface and interior of the separation membrane due to continuous use. As a result, the filtration performance of the separation membrane deteriorates over time. Therefore, a water treatment facility using a separation membrane is provided with a membrane cleaning facility for cleaning the separation membrane, and the separation membrane is periodically cleaned by the membrane cleaning facility.

A cleaning method using ozone has been proposed as a cleaning method for separation membranes in membrane cleaning equipment. Ozone is unstable and prone to self-decomposition, and its lifetime especially in water is extremely short. For example, the half-life of ozone in water is about 10 minutes at normal temperature and normal pressure. The half-life of ozone in water is also affected by pH, temperature, and the like. For this reason, depending on the transportation distance, transportation time, transportation environment, etc. from the generation of the ozonated water to the separation membrane to be cleaned, self-decomposition in the ozonated water, that is, consumption of ozone that does not contribute to the cleaning of the separation membrane. can no longer be ignored. Therefore, in order to compensate for the ineffective consumption of ozone, there is a problem that it is necessary to provide an excessive capacity ozone gas generation source or to supply ozone gas for an excessive time.

Patent Literature 1 discloses a membrane cleaning method for cleaning a separation membrane by circulating ozone water through the separation membrane to decompose organic matter adhering to the separation membrane. In the membrane cleaning method described in Patent Document 1, the pH of the ozone water is maintained at 2 to 5 using a pH adjuster, thereby suppressing the self-decomposition of dissolved ozone and solving the above problem.

Japanese Patent No. 6430091

However, in the technique described in Patent Document 1, the pH of ozone water is maintained at 2 to 5 by supplying an acid, that is, an acid solution, to an ozone water generator that dissolves ozone gas in water to be dissolved. Therefore, a storage unit for storing acid is provided around the ozonated water generating unit, which imposes restrictions on installation.

The present disclosure has been made in view of the above, and an object of the present disclosure is to obtain an ozonated water production apparatus capable of suppressing ineffective consumption of ozone while suppressing restrictions on installation.

In order to solve the above-described problems and achieve the object, the ozone water production apparatus according to the present disclosure includes a first gas supply unit that supplies a first gas containing oxygen gas, carbon dioxide gas, nitrogen gas, and nitrogen oxidation gas. a second gas supply unit for supplying a second gas containing at least one of the material gases. Further, the ozonized water production apparatus performs discharge treatment on a gas containing the first gas supplied by the first gas supply unit and the second gas supplied by the second gas supply unit, thereby producing a third gas containing ozone gas. an ozonated water generator that generates ozonated water by dissolving the third gas in the water to be dissolved; and a control unit that controls the amount of by-products produced by subjecting the second gas to the discharge treatment .

The ozonated water production apparatus according to the present disclosure has the effect of being able to suppress ineffective consumption of ozone while suppressing restrictions on installation.

The figure which shows the structural example of the water treatment apparatus concerning Embodiment 1. FIG. 4 shows a configuration example of a control circuit according to Embodiment 1; Flowchart showing an example of the control procedure for ozone water production in the condition control unit of Embodiment 1 The figure which shows the structural example of the water treatment apparatus concerning Embodiment 2. FIG. 10 is a diagram showing a configuration example of an ozonated water production apparatus according to a third embodiment; The figure which shows the structural example of the ozone water manufacturing apparatus concerning Embodiment 4. The figure which shows the structural example of the ozone water manufacturing apparatus concerning Embodiment 5. A diagram showing a configuration example of an ozonated water production apparatus according to a sixth embodiment. A diagram showing a configuration example of an ozonated water production apparatus according to a seventh embodiment. A diagram showing a configuration example of an ozonated water production apparatus according to an eighth embodiment. A diagram showing a configuration example of an ozone water production apparatus according to a ninth embodiment. FIG. 11 shows a configuration example of an ozonated water production apparatus according to a tenth embodiment; FIG. 11 shows a configuration example of an ozonated water production apparatus according to an eleventh embodiment;

An ozonated water production apparatus, a water treatment apparatus, and an ozonated water production method according to embodiments will be described below in detail with reference to the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a water treatment apparatus according to Embodiment 1. FIG. The water treatment apparatus of the present embodiment purifies water to be treated such as sewage or industrial wastewater by a membrane bioreactor (MBR) method. As shown in FIG. 1, the water treatment apparatus includes a treatment tank 10, a separation membrane 11, a membrane state measuring unit 20, a switching valve 21, a process control unit 22, a filtered water pump 23, and an ozonized water producing apparatus that functions as a membrane cleaning apparatus. A device 100 is provided.

The water to be treated is introduced into the treatment tank 10 through the water to be treated pipe 1a. The water to be treated is biodegraded by activated sludge in the treatment tank 10, filtered from the primary side to the secondary side in the separation membrane 11, and discharged through the filtered water pipe 2a and the discharge pipe 2b. be done. In the present embodiment, purification is performed by MBR, which performs solid-liquid separation into activated sludge and membrane-filtered clarified water with the separation membrane 11. Therefore, a final sedimentation tank is not required, and an extremely simple and compact water treatment apparatus is realized. can. Further, the water treatment apparatus of the present embodiment performs a membrane filtration process for purifying water to be treated and a membrane cleaning process for cleaning the separation membrane 11 . By performing the membrane cleaning step, the filtration performance of the separation membrane 11 can be maintained.

A film state measuring unit 20 and a switching valve 21 are provided in the filtered water pipe 2a. The switching valve 21 is connected to the discharge pipe 2b provided with the filtered water pump 23 and the membrane cleaning pipe 3d provided with the ozone water production device 100 . The switching valve 21 switches the connection destination of the filtered water pipe 2a between the discharge pipe 2b and the membrane cleaning pipe 3d based on instructions from the process control unit 22 .

The process control unit 22 manages the membrane filtration process and the membrane washing process. When shifting from the membrane filtration process to the membrane cleaning process, the process control unit 22 instructs the switching valve 21 to connect the filtered water pipe 2a to the membrane cleaning pipe 3d. Further, the process control unit 22 instructs the switching valve 21 to connect the filtered water pipe 2a to the discharge pipe 2b when shifting from the membrane cleaning process to the membrane filtration process. When the filtered water pipe 2a is connected to the discharge pipe 2b by the switching valve 21, the membrane-filtered clarified water is discharged through the discharge pipe 2b. When the filtered water pipe 2a is connected to the membrane cleaning pipe 3d by the switching valve 21, the separation membrane 11 is cleaned by the ozone water production device 100, which is a membrane cleaning device.

In the process of obtaining clarified water through membrane filtration by the separation membrane 11 after biodegradation, contaminants including sludge, suspended solids, microorganisms, metabolites of microorganisms, etc. adhere to the surface and inside of the separation membrane 11. Or stick. As a result, the membrane permeation differential pressure, which is the difference between the pressure on the secondary side of the membrane during the membrane filtration process and the atmospheric pressure, increases, and the filtration performance such that the flux, which is the amount of filtered water per unit time and per unit membrane filtration area, decreases. deterioration over time occurs. Therefore, in order to maintain the filtration performance of the separation membrane 11, it is necessary to perform a membrane cleaning step for cleaning and removing contaminants from the inside and surface of the separation membrane. In the membrane cleaning step of the present embodiment, ozone water is supplied as a cleaning liquid in the direction from the secondary side to the primary side of the separation membrane 11, which is the opposite direction to the flow of filtered water, while membrane filtration is stopped. As a result, contaminants on the separation membrane 11 can be effectively washed and removed. After recovering the transmembrane pressure difference and flux of the separation membrane 11 by the membrane washing process, the membrane filtration process is restarted. According to this cleaning method, the membrane filtration step and the membrane cleaning step can be switched at desired timing while the separation membrane 11 is immersed in the water to be treated in the treatment tank 10, thereby maintaining the filtration performance and It is possible to realize simplification of maintenance of water treatment equipment.

The process transition between the membrane filtration process and the membrane washing process will be specifically described. The membrane state measuring section 20 measures the state of contamination of the separation membrane 11 and outputs the measured value to the process control section 22 . For example, the membrane state measuring unit 20 measures at least one of the transmembrane pressure difference and the flux of the separation membrane 11 . The process control unit 22 compares the threshold value stored in the storage unit in the process control unit 22 with the measured value, and determines whether or not to perform the process transition based on the comparison result. For example, when the membrane state measuring unit 20 measures the transmembrane pressure difference, the process control unit 22 shifts the process from the membrane filtration process to the membrane washing process when the transmembrane pressure difference, which is the measured value, exceeds the threshold value. Then, the switching valve 21 is instructed to connect the filtered water pipe 2a to the membrane cleaning pipe 3d. Then, the process control unit 22 determines to shift the process from the membrane cleaning process to the membrane filtration process when the transmembrane pressure difference, which is the measured value, falls below the threshold value, and connects the filtered water pipe 2a to the switching valve 21. The operator is instructed to use the discharge pipe 2b as the destination. When the membrane state measuring unit 20 measures the flux, the process control unit 22 shifts the process from the membrane filtration process to the membrane cleaning process when the measured value of the flux falls below the threshold value, and the measured value exceeds the threshold value. When it exceeds, the process is changed from the membrane cleaning process to the membrane filtration process.

Note that the threshold value for determining the process transition from the membrane cleaning process to the membrane filtration process and the threshold value for determining the process transition from the membrane filtration process to the membrane cleaning process may be different. For example, when the membrane state measuring unit 20 measures the transmembrane differential pressure, the threshold for determining the process transition from the membrane cleaning process to the membrane filtration process is set to determine the process transition from the membrane filtration process to the membrane washing process. It may be set to a value smaller than the threshold for When the membrane state measuring unit 20 measures the flux, the threshold value for determining the process transition from the membrane cleaning process to the membrane filtration process is set to the threshold value for determining the process transition from the membrane filtration process to the membrane cleaning process. You can set it to a higher value. Further, when the membrane state measuring unit 20 measures both the transmembrane pressure difference and the flux of the separation membrane 11, the process control unit 22 determines whether one of the transmembrane pressure difference and the flux satisfies the conditions for process transition. In this case, the process transition may be performed, or the process transition may be performed when both of the conditions for the process transition are satisfied.

As described above, by repeating the process transition according to the measurement value of the membrane state measuring unit 20, the treatment of the water to be treated can be continued without impairing the desired filtration performance. The process transition between the membrane filtration process and the membrane cleaning process is not limited to the above example. For example, when the operation time of the membrane filtration process exceeds a predetermined time, the membrane cleaning process is performed for a certain period of time, and the membrane filtration process is performed again. Membrane cleaning may be performed periodically, such as by transitioning and clearing the operating time. In this case, it may be possible to change the interval at which the membrane filtration process is performed and the duration of the membrane cleaning process.

Next, the configuration and operation of the ozone water production device 100 will be described. The ozone water production apparatus 100 includes an oxygen gas supply unit 30, other gas supply unit 31, ozone gas generation unit 32, ozone water generation unit 34, ozone water state measurement unit 35, ozone water pump 36, condition control unit 37, and exhaust ozone. A processor 38 is provided.

The oxygen gas supply unit 30 is a first gas supply unit that supplies oxygen gas, which is an example of the first gas, to the ozone gas generation unit 32 via the oxygen gas pipe 3a. The other gas supply unit 31 is a second gas supply unit that supplies the other gas, which is the second gas, to the ozone gas generation unit 32 via the other gas pipe 3b. The other gas is, for example, carbon dioxide gas. An example in which carbon dioxide gas is used as the other gas will be described below, but the other gas is not limited to carbon dioxide gas, and may be nitrogen gas or nitrogen oxide gas. Carbon dioxide gas, nitrogen gas and Any gas containing at least one of nitrogen oxide gases may be used.

An oxygen gas supply unit 30 and another gas supply unit 31 are connected to the ozone gas generation unit 32 via the oxygen gas pipe 3a and the other gas pipe 3b, respectively. Oxygen gas and other gases are supplied to the ozone gas generator 32 through the oxygen gas pipe 3a and the other gas pipe 3b. The ozone gas generator 32 generates ozone by discharge treatment such as dielectric barrier discharge using oxygen gas and other gases. That is, the ozone gas generator 32 performs discharge treatment on a gas containing the first gas supplied by the first gas supply unit and the second gas supplied by the second gas supply unit, thereby producing a third gas containing ozone gas. is a discharge part that generates In the ozone gas generator 32, oxygen molecules are dissociated by the action of electric discharge, and ozone is generated from the dissociated oxygen atoms and oxygen molecules. Here, in the ozone gas generator 32, carbon dioxide is simultaneously dissociated in the same manner as oxygen molecules are dissociated. Therefore, the third gas, which is the gas generated by the ozone gas generator 32, contains not only ozone but also carbonate-based by-products resulting from carbon dioxide. Hereinafter, for the sake of simplification, the gas generated by the ozone gas generator 32 will be referred to as ozone gas, but as described above, this ozone gas contains carbonic acid by-products.

The ozone gas generated by the ozone gas generator 32 is supplied to the ozone water generator 34 through the ozone gas pipe 3c. Further, the dissolved water is supplied to the ozone water generator 34 through the dissolved water pipe 3e. In addition, the ozone water generator 34 stores the supplied dissolved water. The ozone water generating unit 34 includes an ozone injection unit 33, and the ozone injection unit 33 generates ozone water by dissolving the third gas generated by the ozone gas generating unit 32 in the water to be dissolved. The ozone gas supplied through the ozone gas pipe 3c is introduced into the water to be dissolved. As a result, the ozone gas is dissolved in the water to be dissolved to generate ozone water. The ozone water generated and stored by the ozone water generator 34 is supplied to the separation membrane 11 to be cleaned through the ozone water pump 36 and the membrane cleaning pipe 3d. That is, the ozone water generated by the ozone water generator 34 is used as a cleaning agent for cleaning the separation membrane 11 . On the other hand, the undissolved ozone gas is introduced into the exhaust ozone treatment device 38 via the exhaust ozone gas pipe 3f. The exhaust ozone treatment device 38 detoxifies the ozone gas and releases it into the atmosphere.

The pH of the ozonated water generated and stored in the ozonized water generating unit 34 is preferably maintained at 6 or less, and within the range of 3 to 5, in order to suppress self-decomposition of dissolved ozone. is more preferable. Hereinafter, the conditions for keeping the ozonated water acidic are referred to as acidic conditions. The acidic condition may be, as described above, a condition that the pH is 6 or less, or a condition that the pH is within a specified range. The specified range is, for example, the range of 3 to 5, that is, the pH range of 3 or more and 5 or less, but is not limited thereto.

Since carbonate-based by-products such as carbonate ions and bicarbonate ions contained in the ozone gas supplied from the ozone gas generator 32 lower the pH of the water to be dissolved, the pH of the ozonized water in the present embodiment is It depends on how much the by-product dissolves in the water to be dissolved together with the ozone gas. Therefore, by controlling the supply of carbon dioxide supplied from the other gas supply unit 31, the pH of the ozone water can be controlled. Specifically, by controlling the supply of carbon dioxide supplied from the other gas supply unit 31 so as to maintain the acidic conditions, the dissolution of the carbonate-based by-products can be controlled, and the dissolved ozone self-decomposes. It is suppressed, and a long life of dissolved ozone and an improvement in dissolved ozone concentration are achieved. Carbonate-based by-products also act as radical scavengers that scavenge hydroxyl radicals generated by the decomposition of ozone in water. That is, the reaction of the carbonate-based by-product with the hydroxyl radical suppresses the progress of the decomposition reaction of ozone.

The temperature of the ozone water generator 34 may be room temperature, but is preferably maintained at 30° C. or lower, more preferably 20° C. or lower, so that the above-mentioned acidic conditions are maintained to suppress self-decomposition of dissolved ozone, The effect of suppressing self-decomposition of dissolved ozone by keeping the temperature low can be obtained. As described above, the ozonized water produced by the ozonated water producing apparatus 100 in the present embodiment stabilizes dissolved ozone in the ozonized water, increases the concentration, and Long life can be achieved.

The ozonated water state measuring unit 35 measures the amount indicating the pH state of the ozonated water. The amount indicating the state of the pH of the ozonated water may be the pH of the ozonized water itself or the dissolved ozone concentration. That is, the ozonated water state measuring unit 35 may measure the pH of the ozonated water, or may measure the dissolved ozone concentration of the ozonated water. In FIG. 1, the ozonated water state measuring unit 35 is provided in the ozonized water generating unit 34, but the position of the ozonized water state measuring unit 35 is not limited to the position shown in FIG. A measurement unit 35 may be provided.

The condition control section 37 cooperates with the process control section 22 to control the production of ozonated water. As described above, the process control unit 22 controls the transition of processes. The process control unit 22 notifies the condition control unit 37 of the start of the membrane cleaning process when shifting to the membrane cleaning process, and starts the membrane filtration process when ending the membrane cleaning process and shifting to the membrane filtration process. is notified to the condition control unit 37 . When the condition control unit 37 is notified of the start of the membrane cleaning process, it starts producing ozone water and supplying the ozone water. Specifically, the condition control unit 37 controls the oxygen gas supply unit 30, the other gas supply unit 31, and the ozone gas generation unit 32 based on various conditions for producing ozonated water as described later, thereby producing ozonated water. is produced, and the ozonated water is fed by driving the ozonized water pump 36 . The ozone water sent by the ozone water sending pump 36 is supplied to the separation membrane 11 via the membrane cleaning pipe 3d, the switching valve 21 and the filtered water pipe 2a. When the start of the membrane filtration process is notified after the membrane cleaning process, the condition control unit 37 may stop the production of ozonated water and the supply of ozonated water, or continue the production of ozonized water and continue the production of ozonated water. water supply may be stopped. When the production of ozonized water is continued in the membrane filtration process, the produced ozonated water is stored in the ozonated water generator 34, and the condition control part 37 is notified of the start of the membrane filtration process again. By driving the water supply pump 36, the supply of ozone water is started. When the production of ozonated water is continued in the membrane filtration step, the condition control unit 37 may stop the production of ozonated water when the amount of stored ozonated water reaches a threshold value.

In this manner, the condition control unit 37 that controls the production of ozonized water and the process control unit 22 that controls the process according to the state of the separation membrane 11 perform their respective controls, and both control in cooperation. As a result, a water treatment apparatus with a high degree of freedom and excellent running costs can be realized.

The condition control unit 37 is implemented by a processing circuit. This processing circuit may be dedicated hardware or may be a control circuit comprising a processor. If dedicated hardware, the processing circuit may be, for example, a single circuit, a decoding circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or A combination of these is applicable.

FIG. 2 is a diagram showing a configuration example of the control circuit of this embodiment. A processing circuit that implements the condition control unit 37 may be, for example, the control circuit shown in FIG. The control circuit shown in FIG. 2 comprises a processor 201 and memory 202 .

The processor 201, which is an arithmetic device, is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor). The memory 202, which is a storage unit, includes, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory). Such as semiconductor memory, magnetic disk, flexible disk, and the like.

When the condition control section 37 is realized by the control circuit shown in FIG. 2, the function of the condition control section 37 is realized by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and stored in the memory 202. The functions of the condition control unit 37 are realized by the processor 201 reading and executing the programs stored in the memory 202. FIG. Further, when information is recorded while the program is being executed by the processor 201 , the data is held in the memory 202 . This program may be provided by a program storage medium, which is a storage medium, or may be provided by a communication medium or the like.

Also, the condition control unit 37 may be implemented by a combination of a processing circuit, which is dedicated hardware, and the control circuit shown in FIG. Note that the process control unit 22 described above is also implemented by a processing circuit in the same manner as the condition control unit 37, and this processing circuit may be dedicated hardware or may be a control circuit including a processor. and combinations thereof.

Next, details of control by the condition control unit 37 will be described. The condition control unit 37 is a control unit that controls the amount of by-products produced by subjecting other gases such as carbon dioxide to the discharge treatment. Specifically, the condition control unit 37 controls each part of the ozonated water production apparatus 100 so as to satisfy various conditions related to production of ozonated water when producing ozonated water. Various conditions include the acidic conditions described above. Various conditions include gas conditions and discharge conditions in addition to acidic conditions. Based on the target dissolved ozone concentration in the produced ozonated water, the condition control unit 37 controls the gas condition and the discharge condition so that the pH corresponding to the measurement value of the ozonated water condition measuring unit 35 satisfies the acidic condition. to decide.

The gas condition is a condition relating to the gas flow rate value of at least one of oxygen gas and carbon dioxide gas, and is a condition that determines the ratio of carbon dioxide gas in the raw material gas. For example, by keeping the flow rate of oxygen gas constant and increasing or decreasing the flow rate of carbon dioxide gas, the ratio of carbon dioxide gas in the raw material gas may be increased or decreased, or by keeping the flow rate of carbon dioxide gas constant and oxygen gas The ratio of carbon dioxide gas in the raw material gas may be increased or decreased by increasing or decreasing the flow rate of the gas. Alternatively, the ratio of carbon dioxide gas in the raw material gas may be increased or decreased by increasing or decreasing the flow rates of both oxygen gas and carbon dioxide gas. The amount of dissolved ozone can be increased by appropriately adjusting the discharge power and the flow rate of oxygen gas. Dissolved ozone can be increased.

The discharge condition is at least one of gas pressure, temperature, current, voltage and discharge power in the discharge process. That is, the discharge condition indicates at least one of the gas pressure of the discharge field, which is the ozone gas generation field in the discharge process of the ozone gas generator 32, the current applied to the discharge field, the discharge power based on the voltage, and the temperature of the discharge field. . For example, by adjusting the discharge power, gas pressure, and temperature of the discharge field of the ozone gas generator 32, the amount of dissociation of carbon dioxide can be controlled, and the amount of carbonic acid by-products produced can be adjusted. The temperature of the discharge field can be controlled by at least one of the discharge power and the temperature of the cooling water supplied to the ozone gas generator 32 .

The pH of ozonated water depends on the amount of carbonic acid by-products produced. In addition, the amount of carbonic acid-based by-products produced depends on the flow rate of the carbon dioxide gas supplied from the other gas supply unit 31 and also on the discharge conditions. Therefore, by appropriately setting gas conditions and discharge conditions, acidic conditions can be maintained.

Conditions for adjusting the production amount of carbonate-based by-products so as to maintain acidic conditions are not limited to the examples described above. For example, by adjusting a plurality of gas conditions and discharge conditions in a complex manner, it is possible to control the production amount of carbonate-based by-products, which are by-products when ozone gas is produced, while maintaining the desired production amount of ozone. can be done.

The pH range corresponding to the acidic condition is stored, for example, in the storage section within the condition control section 37 . For example, when the pH corresponding to the measurement value of the ozone water state measuring unit 35 exceeds the upper limit value of the appropriate range defined by the acidic conditions, the condition control unit 37 controls the carbon dioxide gas supplied by the other gas supply unit 31. The gas conditions are determined so as to increase the supply amount of , and the flow rate of the other gas supply unit 31 is controlled based on the determined gas conditions. As a result, the amount of carbonic acid-based by-products produced can be increased, and the pH of the ozone water can be lowered. Thus, by properly controlling the pH of the ozonated water, the dissolved ozone in the ozonized water can be stabilized, increased in concentration, and extended in life. In addition, when the pH corresponding to the measurement value of the ozone water state measuring unit 35 is below the lower limit value of the appropriate range defined by the acidic conditions, the condition control unit 37 controls the carbon dioxide gas supplied by the other gas supply unit 31. The gas conditions are determined so as to reduce the supply amount of , and the flow rate of the other gas supply unit 31 is controlled based on the determined gas conditions. As a result, the amount of carbonic acid-based by-products produced can be reduced, and the pH of the ozone water can be increased. In addition, when only the upper limit value is specified as the acidic condition, the control for reducing the supply amount of carbon dioxide gas may not be performed.

When the ozonized water state measuring unit 35 measures the dissolved ozone concentration, a range of the dissolved ozone concentration corresponding to the proper range of pH defined as the acidic condition is determined in advance. The condition control unit 37 stores this range of dissolved ozone concentration in the storage unit, and similarly to the above, when the measured value of the dissolved ozone concentration becomes lower than the lower limit of the stored range, another The amount of carbon dioxide gas supplied from the gas supply unit 31 is increased to increase the amount of carbonic acid by-products produced. As a result, it is possible to stabilize the dissolved ozone in the ozone water, increase its concentration, and extend its life. When the dissolved ozone concentration becomes higher than the upper limit of the stored range, the amount of carbon dioxide gas supplied from the other gas supply unit 31 is reduced to reduce the amount of carbonic acid by-products produced. Note that when only the upper limit value is specified as the acidic condition, only the lower limit value is specified for the dissolved ozone concentration range, so control to reduce the supply amount of carbon dioxide gas need not be performed. In this manner, the condition control section 37 can control the production amount of the carbonate-based by-product by adjusting the flow rate of the other gas supplied from the other gas supply section 31 .

Further, the condition control unit 37 may control the amount of carbonic acid-based by-products produced by adjusting the discharge conditions in the discharge process, and adjust the flow rate of the other gas supplied from the other gas supply unit 31. The amount of carbonic acid-based by-products produced may be controlled in combination with adjustment of discharge conditions. As described above, the condition control unit 37 controls the amount of carbonic acid-based by-products produced so that the measurement value of the ozone water state measurement unit 35 is within a predetermined range.

Thus, the method for producing ozone water according to the present embodiment includes the first gas supply step of supplying oxygen gas and the second gas supply step of supplying other gas. In the method for producing ozone water of the present embodiment, the gas containing the oxygen gas supplied in the first gas supply step and the other gas supplied in the second gas supply step is further subjected to a discharge treatment, thereby producing a gas containing ozone gas. and an ozone water generating step of generating ozone water by dissolving the gas generated in the discharging step in water to be dissolved.

FIG. 3 is a flow chart showing an example of a control procedure for ozone water production in the condition control section 37 of the present embodiment. The processing shown in FIG. 3 is started in a state where ozonized water is not being produced. The condition control unit 37 determines whether or not to start manufacturing ozonated water (step S1), and repeats step S1 if not to start manufacturing ozonated water (step S1 No). For example, when the process control unit 22 notifies the start of the film cleaning process, the condition control unit 37 determines to start producing ozone water. When the process control unit 22 notifies the start of the membrane cleaning process to start the production of ozonized water, the condition control unit 37 also starts feeding the ozonized water by driving the ozonated water pump 36 . Note that the condition control unit 37 may, for example, periodically start the production of ozonated water without being interlocked with the notification of the start of each step from the process control unit 22 . In this case, the produced ozone water is stored in the ozone water generator 34 . When the start of the membrane filtration process is notified, the condition control unit 37 drives the ozonized water pump 36 to start feeding ozonized water.

When production of ozonized water is started (step S1 Yes), the condition control unit 37 determines whether or not the measured value exceeds the proper range (step S2). The measured value is the result measured by the ozone water state measuring unit 35 . Here, it is assumed that the ozone water state measuring unit 35 measures pH. Further, here, assuming that an upper limit value and a lower limit value of pH are defined as the appropriate range, in detail, in step S2, the condition control unit 37 determines whether the measured value exceeds the upper limit value of the appropriate range. to judge.

If the measured value does not exceed the proper range (step S2 No), the condition control section 37 determines whether the measured value falls below the proper range (step S3). Specifically, the condition control section 37 determines whether or not the measured value is below the lower limit of the appropriate range. If the measured value is not below the appropriate range (step S3 No), the condition control unit 37 determines whether or not to stop the production of ozone water (step S4). For example, when the process control unit 22 notifies the condition control unit 37 of starting the membrane filtration process, the condition control unit 37 determines to stop the production of ozone water. As described above, the production of ozonated water may be continued even after the start of the membrane filtration process is notified. The start of the membrane filtration process stops the production of ozonated water by a trigger other than the notification. When determining not to stop the production of ozonated water (step S4 No), the condition control unit 37 performs the process from step S2 again.

If the measured value exceeds the appropriate range (Yes at step S2), the condition control unit 37 increases the amount of by-products generated during ozone gas generation (step S5), and advances the process to step S4. The amount of by-products produced when ozone gas is produced indicates the amount of by-products produced relative to the amount of ozone gas produced when ozone gas is produced. In step S5, the condition control unit 37 adjusts the gas conditions so as to increase the amount of by-products generated when the ozone gas is generated, for example, by increasing the flow rate of the carbon dioxide gas supplied from the other gas supply unit 31. do. In addition, the condition control unit 37 may increase the amount of by-products produced during ozone gas production by adjusting the discharge conditions, or may adjust both the gas conditions and the discharge conditions to adjust the by-products produced during ozone gas production. Product yield may be increased.

If the measured value is below the appropriate range (Yes at step S3), the condition control unit 37 reduces the amount of by-products generated during ozone gas generation (step S6), and proceeds to step S4. In step S6, the condition control unit 37 may adjust the gas conditions, the discharge conditions, or both the gas conditions and the discharge conditions, as in step S5.

When determining to stop the production of ozonated water (step S4 Yes), the condition control section 37 terminates the process. After the processing ends, the processing shown in FIG. 3 is performed again. When the ozone water state measuring unit 35 measures the dissolved ozone concentration, the condition control unit 37 determines in step S2 that the measured value is below the lower limit of the dissolved ozone concentration range corresponding to the appropriate pH range. In step S3, it is determined whether or not the dissolved ozone concentration exceeds the upper limit of the range.

Through the above processing, the pH of the ozone water produced by the ozone water production apparatus 100 is controlled by the dissolution of the carbonate ions and bicarbonate ions supplied from the ozone gas generator 32, and the acidic conditions can be maintained. By maintaining the pH of the ozonized water under the acidic conditions, the self-decomposition of dissolved ozone is suppressed, and the life of dissolved ozone is extended and the dissolved ozone concentration is improved. In addition, the reaction product with the carbonate-based by-product also acts as a radical scavenger that scavenges hydroxyl radicals generated by the decomposition of ozone in water. As described above, the reaction product with the carbonate-based by-product supplied from the ozone gas generator 32 can stabilize dissolved ozone in the ozone water, increase its concentration, and extend its life.

In the example described above, the condition control unit 37 dynamically controls the amount of by-products such as carbonate-based by-products based on the measurement value of the ozone water state measuring unit 35. , the method of controlling the amount of by-products produced is not limited to this. At least one of the gas conditions and the discharge conditions is predetermined so as to satisfy the acid conditions, and the oxygen gas supply unit 30 and the other gas supply unit 31 supply oxygen gas and other gases, respectively, according to the predetermined gas conditions. The ozone gas generator 32 may perform discharge processing according to predetermined discharge conditions. The other gas supply unit 31 and the oxygen gas supply unit 30 each have an adjustment unit for adjusting the flow rate. When the gas conditions are determined so as to satisfy the acid conditions, the adjustment section of the other gas supply section 31 serves as a control section for controlling the amount of by-products produced. When the discharge conditions are determined so as to satisfy the acid conditions, the controller that controls the discharge in the ozone gas generator 32 becomes the controller that controls the amount of by-products produced.

In the above example, carbon dioxide gas is used as the other gas, but nitrogen or nitrogen oxide gas can be used as the other gas instead of carbon dioxide to obtain the same effect. When nitrogen or nitrogen oxide gas is used as the other gas, the amount of nitrate-based by-products produced simultaneously with ozone by discharge is controlled so as to maintain acidic conditions. Thereby, the pH of the ozone water is controlled by the dissolution of the nitrate ions supplied from the ozone gas generator 32, and acts to maintain the acidic condition. By maintaining the pH of the ozonated water at an acidic condition, the self-decomposition of dissolved ozone is suppressed, and the lifetime of dissolved ozone is extended and the dissolved ozone concentration is improved. In addition, nitric acid by-products or reaction products with nitric acid by-products also act as radical scavengers that scavenge hydroxyl radicals generated by decomposition of ozone in water. As described above, the nitric acid-based by-products supplied from the ozone gas generator 32 or the reaction products with the nitric acid-based by-products can stabilize dissolved ozone in ozone water, increase its concentration, and extend its life. Also, a mixed gas in which two or more of carbon dioxide, nitrogen and nitrogen oxide are mixed may be used as the other gas. Therefore, the other gas may contain at least one of carbon dioxide gas, nitrogen gas and nitrogen oxide gas. When a mixed gas is used as the other gas, for example, a mixed gas in which carbon dioxide is 0.1% or more with respect to the oxygen flow rate can be used. When a mixed gas is used as the other gas, the amounts of nitrate-based and carbonate-based by-products produced simultaneously with ozone by discharge are controlled so as to maintain the acidic conditions.

Also, the same effect can be obtained by supplying the first gas containing oxygen such as air to the ozone gas generator 32 instead of oxygen. That is, the oxygen gas supply section 30, which is the first gas supply section, supplies the first gas containing oxygen gas. In this case, the amounts of nitrate-based and carbonate-based by-products produced simultaneously with ozone by discharge are controlled so as to maintain acidic conditions. As a result, the pH of the ozone water is controlled by the dissolution of nitrate ions, carbonate ions, bicarbonate ions, etc. supplied from the ozone gas generator 32, and acts to maintain acidic conditions. Also, when air is used as the first gas, the nitrogen in the air produces a nitric acid-based by-product, so the second gas need not be used. That is, in this case, air serves as both the first gas and the second gas. By maintaining the pH of the ozonated water at an acidic condition, the self-decomposition of dissolved ozone is suppressed, and the lifetime of dissolved ozone is extended and the dissolved ozone concentration is improved. In addition, the nitric acid by-product, the reaction product with the nitric acid by-product, and the carbonic acid by-product also act as radical scavengers that scavenge hydroxyl radicals generated by the decomposition of ozone in water. As described above, the nitrate-based by-products supplied from the ozone gas generator 32 or the reaction products with the nitric acid-based by-products and the carbonate-based by-products stabilize, increase the concentration of, and lengthen dissolved ozone in the ozone water. Longer service life can be achieved.

According to this embodiment, it is possible to extend the life of ozone dissolved in the generated ozone water. Note that the life of dissolved ozone is shorter than that of ozone gas. Therefore, it is preferable that the ozone water is transported over a short distance, and the ozone water generator 34 is preferably installed near the separation membrane 11 to be cleaned. By arranging the ozone water generator 34 in the vicinity of the separation membrane 11, self-decomposition of ozone can be further suppressed, and highly efficient supply of ozone can be realized. Specifically, for example, the ozonated water generator 34 is arranged so that the distance over which ozone water is transported is shorter than the distance over which ozone is transported in a gaseous state. For example, by setting the length of the ozone gas pipe 3c shown in FIG. 1 to be longer than the total length of the membrane cleaning pipe 3d and the filtered water pipe 2a, the transportation distance as ozone water can be relatively reduced. .

In the ozone gas generator 32, when the oxygen gas purity in the raw material gas is 99% or higher, the ozone gas cannot be generated with high efficiency. In this case, by adding a small amount of at least one of carbon dioxide, nitrogen, and nitrogen oxide gas to the raw material gas relative to oxygen gas, the discharge state or chemical reaction state is optimized, and ozone gas can be generated with high efficiency. can be maintained. That is, the addition of the other gas to the raw material gas in the present embodiment not only stabilizes dissolved ozone in the ozone water to be generated, increases its concentration, and extends the life of the ozone gas, but also increases the efficiency of the ozone gas generator 32. also contribute significantly.

As described above, using the carbonic acid-based by-product or nitric acid-based by-product that is by-produced during ozone gas production, gas The pH of the ozone water can be arbitrarily controlled by adjusting the conditions or discharge conditions. As a result, high-efficiency generation of ozonated water is realized by stabilizing, increasing the concentration, and extending the service life of the ozonated water, and the desired amount of ozonized water can be easily produced as ozonated water without increasing the size and complexity of the ozonated water production apparatus. Can be provided for separation membrane cleaning. Further, in the case of individually adjusting and dissolving the three fluids of the water to be dissolved, the ozone gas, and the acid or the alkali to obtain a desired pH, it is troublesome to individually adjust the three fluids. On the other hand, in the present embodiment, the ozone gas generator 32 adjusts two types of fluids, the mixed gas (for example, ozone gas and carbonic acid gas) and the water to be dissolved, to obtain a desired pH. The pH can be controlled with reduced labor compared to the case of individually adjusting the three fluids.

Embodiment 2.
FIG. 4 is a diagram illustrating a configuration example of a water treatment apparatus according to a second embodiment; The water treatment apparatus of this embodiment is the same as the water treatment apparatus of the first embodiment, except that a regulating valve 25 and a water-to-be-dissolved water storage tank 26 are added. Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

In the present embodiment, a regulating valve 25 is provided in the discharge pipe 2b, and the discharge pipe 2b is connected to the to-be-dissolved water storage tank 26 via the regulating valve 25. As shown in FIG. The to-be-dissolved water storage tank 26 is connected to a to-be-dissolved water pipe 3 e that supplies the to-be-dissolved water to the ozone water generator 34 . In addition, the water treatment apparatus may not include the water-to-be-dissolved water storage tank 26 .

In the membrane filtration step, filtered water flows through the discharge pipe 2b via the filtered water pump 23, as described in the first embodiment. In this embodiment, the process controller 22 also controls the regulating valve 25 . In the membrane filtration process, the process control unit 22 controls the adjustment valve 25 so that at least part of the filtered water flows toward the water-to-be-dissolved pipe 3e. The filtered water that has passed through the discharge pipe 2b and the regulating valve 25 is stored in the water-to-be-dissolved water storage tank 26 as water to be dissolved. The dissolved water stored in the dissolved water storage tank 26 is supplied to the ozone water generator 34 through the dissolved water pipe 3e. If the water to be dissolved storage tank 26 is not provided, filtered water that has passed through the discharge pipe 2b and the regulating valve 25 is supplied to the ozone water generator 34 via the water to be dissolved pipe 3e. Thus, in the present embodiment, water to be dissolved is filtered water filtered by separation membrane 11 .

Operations of the present embodiment other than those described above are the same as those of the first embodiment. In this embodiment, the same effect as in Embodiment 1 can be obtained, and by using filtered water as dissolution water, running of the dissolution water is greater than when tap water or the like is used as the dissolution water. Cost can be reduced. Moreover, in this embodiment, the water treatment apparatus can be installed even in a place where there is no tap water supply source nearby. Moreover, when the water treatment apparatus is installed in a place where there is no supply source of tap water in the vicinity, there is no need to construct a long-distance pipe for introducing tap water, which is economical. In some cases, filtered water contains more organic matter than tap water, and it is conceivable that a part of ozone is consumed to decompose organic matter contained in dissolved water when ozonated water is produced. However, in the present embodiment, the amount of ozone consumed in the decomposition of organic matter contained in the water to be dissolved has the effect of maintaining the pH of the ozonated water within an appropriate range, This is extremely small compared to the amount of ineffective consumption of ozone that can be reduced by suppressing self-decomposition due to the trapping effect.

Embodiment 3.
FIG. 5 is a diagram showing a configuration example of an ozonated water production apparatus according to a third embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100a shown in FIG. 5 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

In this embodiment, the ozone gas that is not dissolved in the water to be dissolved in the ozone water generator 34 is reused. The ozone water production apparatus 100a of the present embodiment includes a circulation fan 39 instead of the exhaust ozone treatment apparatus 38 of the ozone water production apparatus 100 of the first embodiment. The undissolved ozone gas is discharged from the ozone water generator 34 as exhaust ozone gas to the exhaust ozone gas pipe 3f, and introduced into the ozone gas pipe 3c by the circulation fan 39. FIG. Thus, in the present embodiment, the third gas that has not been dissolved in the water to be dissolved in the ozone water generating section 34 is introduced into the ozone water generating section 34 .

In this embodiment, the same effect as in Embodiment 1 can be obtained, and by adding the ozone gas that has not been consumed in the ozone water generating section 34 to the ozone gas supplied from the ozone gas generating section 32, the utilization efficiency of the ozone gas is improved. be improved. In addition, a reduction in power consumption for generating ozone in the ozone gas generator 32 and a reduction in running costs such as power consumption and raw material gas costs can be expected.

Embodiment 4.
FIG. 6 is a diagram showing a configuration example of an ozonated water production apparatus according to a fourth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100b shown in FIG. 6 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1 is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

The ozonized water producing apparatus 100b of the present embodiment is the same as the ozonized water producing apparatus 100 of the first embodiment, except that an ozone gas concentration storage unit 40 and a circulation fan 41 are added. In the ozone water production apparatus 100b of Embodiment 4, the ozone gas generated by the ozone gas generator 32 is supplied to the ozone water generator 34 through the ozone gas concentration storage unit 40. FIG. The ozone gas concentration storage unit 40 , which is an ozone gas separation unit, separates ozone and oxygen in the ozone gas generated by the ozone gas generation unit 32 . The ozone separated by the ozone gas concentration storage unit 40 is introduced into the ozone water generation unit 34 as concentrated ozone gas. On the other hand, the oxygen separated by the ozone gas concentration storage unit 40 is returned as recycled oxygen gas to the oxygen gas pipe 3a via the circulation fan 41 and the oxygen recycling pipe 3g. Thereby, the oxygen separated by the ozone gas concentration storage unit 40 is reused as part of the raw material gas of the ozone gas generation unit 32 .

The ozone gas concentration storage unit 40 in the present embodiment has, for example, an adsorption cylinder filled with an adsorbent such as silica gel as a main component. In the adsorption column, by controlling the temperature and pressure, the difference in adsorption and desorption properties of ozone and oxygen on the adsorbent is used to separate ozone and oxygen from the ozone-containing mixed gas. The ozone purity and ozone concentration of the concentrated ozone gas can be changed by controlling the temperature and pressure based on instructions from the condition control section 37 . That is, by adjusting the command from the condition control unit 37, the ozone purity and ozone concentration of the concentrated ozone gas can be arbitrarily set.

By disposing a desorption pump downstream of the ozone gas concentration storage unit 40 and introducing a desorption gas into the ozone gas concentration storage unit 40, desorption of ozone from the adsorbent is promoted when the concentrated ozone gas is extracted from the ozone gas concentration storage unit 40. may A portion of the raw material gas used in the ozone gas generator 32 may be used as the desorption gas. Alternatively, the concentrated ozone gas may be sucked by disposing an ejector downstream of the ozone gas concentration storage unit 40 and introducing the air around the ozone water production apparatus 100b into the ejector as a driving fluid.

In the present embodiment, the same effect as in the first embodiment is obtained, and by separating the ozone gas produced in the ozone gas production section 32 into ozone and oxygen, arbitrarily concentrated ozone gas is produced by the ozone water production section. 34, and the oxygen gas can be recycled as the raw material gas for the ozone gas generating unit 32. Therefore, a reduction in power consumption for ozone generation and a reduction in running costs such as power consumption and raw material gas costs can be expected.

Embodiment 5.
FIG. 7 is a diagram showing a configuration example of an ozonated water production apparatus according to a fifth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100c shown in FIG. 7 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

The ozonated water production apparatus 100c of the present embodiment is obtained by adding a circulation pump 42 to the ozonized water production apparatus 100 of the first embodiment. In the ozonized water production apparatus 100c of the present embodiment, the water to be dissolved stored in the ozonized water producing unit 34 is discharged from the lower part of the ozonated water producing part 34 to the upper part of the ozonized water producing part 34 via the circulation pipe 3h and the circulation pump 42. supplied to Thus, the water to be dissolved is moved by the circulation pump 42 to the upper portion of the ozonized water generating portion 34, the bottom portion of the ozonized water generating portion 34, the bottom portion of the circulation pipe 3h, the upper portion of the circulating pipe 3h, and the upper portion of the ozonized water generating portion 34. Cycle in order. Therefore, in the ozonated water generator 34 , the water to be dissolved flows from the top to the bottom of the ozonated water generator 34 . On the other hand, the ozone gas introduced from the ozone gas generator 32 flows from the bottom to the top in the ozone water generator 34 via the ozone injection part 33 . That is, in the ozone water generator 34, the water to be dissolved and the ozone gas come into contact with each other in a countercurrent manner. The circulation pump 42 may operate only while the ozone gas is being introduced from the ozone gas generator 32 to the ozone water generator 34 .

In this embodiment, the same effect as in Embodiment 1 can be obtained, and since the water to be dissolved and the ozone gas are in countercurrent contact, the efficiency of dissolving the ozone gas in the water to be dissolved is improved. be improved. Since the utilization efficiency of ozone gas in the production of ozone water is improved, the amount of undissolved ozone gas is reduced, and a reduction in the capacity of the waste ozone treatment device 38 can also be expected.

Embodiment 6.
FIG. 8 is a diagram showing a configuration example of an ozonated water production apparatus according to a sixth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100d shown in FIG. 8 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

An ozone water production apparatus 100d of the present embodiment includes an ejector 43 and a circulation pump 44 instead of the ozone injector 33 of the first embodiment. In the ozone water production apparatus 100d of the present embodiment, the ozone gas generator 32 is connected to the ejector 43 through the ozone gas pipe 3c. The ozonized water generator 34 is connected with a circulation pipe 3 i that forms a circulation flow path for the water to be dissolved together with the ozonized water generator 34 . The water to be dissolved introduced into the ozonated water generator 34 is circulated through the ozonized water generator 34 and the circulation pipe 3 i by the circulation pump 44 . The ejector 43 uses the water to be dissolved as a driving fluid and the ozone gas as a suction fluid to perform gas-liquid mixing and dissolution to generate ozone water.

In the present embodiment, the same effect as in Embodiment 1 is obtained, and the water to be dissolved and the ozone gas are mixed and dissolved by the ejector 43, so that the efficiency of dissolving the ozone gas in the water to be dissolved is improved. Improves water production efficiency. Since the utilization rate of ozone gas in the production of ozone water is improved, the amount of undissolved ozone gas is reduced, and a reduction in the capacity of the waste ozone treatment device 38 can also be expected.

Embodiment 7.
FIG. 9 is a diagram showing a configuration example of an ozonated water production apparatus according to a seventh embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100e shown in FIG. 9 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

The ozonized water production apparatus 100e of the present embodiment includes an ozonized water generator 34a instead of the ozonized water generator 34 of the first embodiment, and a circulation pump 46 is added. The dissolved water pipe 3e and the ozone water generator 34a are connected to a circulation pipe 3j that forms a circulation flow path for the dissolved water together with the ozone water generator 34a and the dissolved water pipe 3e. A circulation pump 46 is provided in the circulation pipe 3j. The to-be-dissolved water supplied from the to-be-dissolved water pipe 3e is circulated by the circulation pump 46 through the flow path formed by the ozone water generator 34a, the circulation pipe 3j, and part of the to-be-dissolved water pipe 3e. The ozone water generator 34a is provided with a plurality of barriers 45 that form a plurality of vertical flow paths for the water to be dissolved. The plurality of barriers 45 are installed apart from the top or bottom surface of the ozonated water generator 34a so that one continuous flow path is formed in the ozonated water generator 34a.

In the example shown in FIG. 9, the ozone water generator 34a is divided into two regions by a central barrier 45 provided in contact with the bottom of the ozone water generator 34a, and ozone is injected into the bottom of each region. A section 33 is provided. The central barrier 45 is separated from the upper surface of the ozone water generating part 34a, so that the water to be dissolved can flow from the right area to the left area. Each region is provided with a barrier 45 which is in contact with the top surface of the ozonated water generating section 34a and is installed away from the bottom surface of the ozonated water generating section 34a. This further divides each region into two regions, sub-regions, as shown in FIG. The sub-regions are called first to fourth sub-regions in order from the left. In the example shown in FIG. 9, the water to be dissolved is introduced from the upper portion of the first sub-region of the ozonized water generator 34a through the water-to-be-dissolved pipe 3e, and flows from the top to the bottom within the first sub-region. , flows into the second subregion at the bottom. In the second subdivision the water to be dissolved flows from the bottom to the top and at the top enters the third subdivision. In the third subdivision the water to be dissolved flows from the top to the bottom and enters the fourth subdivision at the bottom. The water to be dissolved that has flowed from the bottom to the top in the fourth subdivision area flows into the circulation pipe 3j connected to the top of the ozone water generator 34a.

In the present embodiment, the water to be dissolved flows from the top to the bottom of the ozonated water generator 34 by forming a circulation flow path for the water to be dissolved. In addition, since the ozone injection part 33 is installed at the bottom of each region, the ozone gas is caused to flow from the bottom to the top of the ozone water generating part 34 . Therefore, the water to be dissolved and the ozone gas come into countercurrent contact. In the example shown in FIG. 9, the inside of the ozonated water generating section 34a is divided into two areas, and the ozone injection section 33 is provided for each area. Alternatively, an ozone injector 33 may be provided for each region. Further, the ozonized water generating unit 34a is provided with one barrier 45 that is in contact with the top surface of the ozonized water generating unit 34a and separated from the bottom surface of the ozonized water generating unit 34a, and has one ozone injection unit 33. good too.

In the present embodiment, the water to be dissolved and the ozone gas are brought into contact with each other in a countercurrent manner because the flow path for the water to be dissolved is formed by the barrier 45 in the ozone water generating section 34a. Therefore, in the present embodiment, the same effect as in the first embodiment is obtained, and the efficiency of dissolving ozone gas in water to be dissolved is improved, so that the efficiency of generating ozone water is improved. Since the utilization efficiency of ozone gas in the production of ozone water is improved, the amount of undissolved ozone gas is reduced, and a reduction in the capacity of the waste ozone treatment device 38 can also be expected.

Embodiment 8.
FIG. 10 is a diagram showing a configuration example of an ozonated water production apparatus according to an eighth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100f shown in FIG. 10 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

An ozonated water production apparatus 100f of the present embodiment includes a membrane module 47 instead of the ozonized water generator 34 of the first embodiment. Membrane module 47 comprises a porous membrane, such as a porous glass membrane. In this embodiment, the ozone gas produced in the ozone gas generator 32 and the water to be dissolved are introduced into the membrane module 47 . The membrane module 47 brings the introduced ozone gas and the water to be dissolved into contact with each other in the pores of the porous membrane, thereby dissolving the ozone gas in the water to be dissolved, thereby generating ozone water. The ozone water is introduced into the membrane cleaning pipe 3 d by the ozone water pump 36 . In this embodiment, the ozone water state measuring unit 35 is installed in the membrane cleaning pipe 3d.

In the present embodiment, the same effect as in the first embodiment can be obtained, and the ozone gas is dissolved in the water to be dissolved by using the membrane module 47. Therefore, the efficiency of dissolving the ozone gas in the water to be dissolved is improved, and the ozone water is improved. Improves production efficiency. The utilization efficiency of ozone gas in the production of ozone water is also improved.

Embodiment 9.
FIG. 11 is a diagram showing a configuration example of an ozonated water production apparatus according to a ninth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1, except that the ozone water production apparatus 100g shown in FIG. 11 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

The ozonized water production apparatus 100g of the present embodiment has a fine bubble generator 48 added to the ozonized water generator 34 of the first embodiment. In this embodiment, the ozone gas generated by the ozone gas generator 32 is introduced into the fine bubble generator 48 . The fine bubble generating section 48 introduces the introduced ozone gas as fine bubbles into the ozone water generating section 34 in which the water to be dissolved is stored. The fine bubbles generated by the fine bubble generator 48 are ultra-fine bubbles with a bubble diameter of 100 μm or less, preferably 1 μm or less. The fine bubble generator 48 may generate fine bubbles by any method such as a pressure dissolution method, a swirling flow method, or a fine hole method, and there is no restriction on the bubble generation method.

In the present embodiment, the same effect as in the first embodiment is obtained, and since the ozone gas is introduced as fine bubbles, the efficiency of dissolving the ozone gas in the water to be dissolved is improved, and the efficiency of generating ozone water is improved. Since the utilization efficiency of ozone gas in the production of ozone water is improved, the amount of undissolved ozone gas is reduced, and a reduction in the capacity of the waste ozone treatment device 38 can also be expected. In addition, when ozone gas becomes ultra-fine bubbles, it will continue to drift in the water to be dissolved by Brownian motion, so unlike bubbles with a large bubble diameter, which will rise due to buoyancy and disappear on the liquid surface, it will have a long life as ozone water. change can be expected.

Embodiment 10.
FIG. 12 is a diagram showing a configuration example of an ozonated water production apparatus according to a tenth embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100h shown in FIG. 12 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

An ozonated water production apparatus 100h of the present embodiment has a fine bubble generator 49 and a circulation pump 50 added to the ozonized water generator 34 of the first embodiment. The ozonated water generator 34 is connected with a circulation pipe 3 k that forms a circulation flow path for the water to be dissolved together with the ozonized water generator 34 . The fine bubble generator 49 and the circulation pump 50 are provided in the circulation pipe 3k. In the present embodiment, the circulation pump 50 circulates the liquid to be dissolved through the circulation channel. The ozone gas generated by the ozone gas generator 32 is introduced into an ejector type fine bubble generator 49 . The fine bubble generator 49 uses the liquid to be dissolved as a driving fluid and ozone gas as a suction fluid to generate fine bubbles. The fine bubbles are ultra-fine bubbles having a bubble diameter of 100 μm or less, preferably 1 μm or less. Ozone water is generated by dissolving the fine bubbles in the water to be dissolved. The ozone water is introduced from the ozone water generator 34 to the membrane cleaning pipe 3 d by the ozone water pump 36 .

In this embodiment, the same effect as in Embodiment 1 is obtained, and the ozone gas becomes fine bubbles, so that the efficiency of dissolving the ozone gas in the water to be dissolved is improved, and the efficiency of generating ozone water is improved. Since the utilization rate of ozone gas in the production of ozone water is improved, the amount of undissolved ozone gas is reduced, and a reduction in the capacity of the waste ozone treatment device 38 can also be expected. In addition, when ozone gas becomes ultra-fine bubbles, it will continue to drift in the water to be dissolved by Brownian motion, so unlike bubbles with a large bubble diameter, which will rise due to buoyancy and disappear on the liquid surface, it will have a long life as ozone water. change can be expected.

Embodiment 11.
FIG. 13 is a diagram showing a configuration example of an ozonated water production apparatus according to an eleventh embodiment. The water treatment apparatus of the present embodiment is the water treatment apparatus of Embodiment 1 except that the ozone water production apparatus 100i shown in FIG. 13 is provided instead of the ozone water production apparatus 100 of the water treatment apparatus of Embodiment 1. is similar to Components having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and descriptions overlapping those of the first embodiment are omitted. Differences from the first embodiment will be mainly described below.

In the ozone water production apparatus 100i of the present embodiment, the membrane cleaning pipe 3d is provided with a switching valve 53. The switching valve 53 includes the ozone water pipe 3m connected to the ozone water generator 34 and hypochlorous acid A sodium hypochlorite solution pipe 3n for supplying a sodium solution is connected. An ozone water pump 36 is provided on the ozone water pipe 3m. The switching valve 53 switches the connection destination of the membrane cleaning pipe 3d between the ozone water pipe 3m and the sodium hypochlorite solution pipe 3n. Switching of the switching valve 53 is performed at a desired timing in the membrane cleaning process. Thus, in the present embodiment, the separation membrane 11 can switch the cleaning agent supplied to the separation membrane 11 between the ozone water and the sodium hypochlorite solution. It is cleaned using both a sodium chlorate solution and a second cleaning agent, ozone water. The sodium hypochlorite solution is supplied from the sodium hypochlorite solution supply unit 51 through the pump 52 and the switching valve 53 to the membrane cleaning pipe 3d. Moreover, although the type of solvent for the sodium hypochlorite solution is not particularly limited, the solvent for the sodium hypochlorite solution may be dissolved water obtained by branching from the dissolved water pipe 3e. The ozone water is sent from the ozone water generator 34 to the membrane cleaning pipe 3 d through the ozone water pump 36 and the switching valve 53 .

In the film cleaning in this embodiment, two types of cleaning agents having different oxidizing powers, ozone water and sodium hypochlorite solution, are used. For example, in the membrane cleaning step, the membrane is first cleaned with a sodium hypochlorite solution, which is a first cleaning agent with relatively low oxidizing power, and then ozone, which is a second cleaning agent with relatively high oxidizing power. A membrane wash with water is performed. Here, the oxidizing power indicates a standard oxidation-reduction potential measured at 25° C. using a hydrogen electrode. The oxidizing power of the first cleaning agent is less than 2.0V, while the oxidizing power of the second cleaning agent is greater than or equal to 2.0V.

The first cleaning agent is effective in oxidatively decomposing and removing easily decomposable organic substances among contaminants adhering and fixed to the separation membrane 11 . In the film cleaning with the first cleaning agent, it is not possible to oxidatively decompose and remove persistent organic substances, but the chemical action of the first cleaning agent reduces the adhesion to the film. is obtained. If the second cleaning agent is applied after obtaining the effect of the first cleaning agent, the oxidative decomposition effect on the persistent organic substances becomes remarkable, and contaminants can be removed from the separation membrane 11 . Cleaning can be achieved by administering a very small amount of cleaning agent rather than oxidatively decomposing the persistent organic matter only with the second cleaning agent.

In the present embodiment, the same effect as in the first embodiment can be obtained. The oxidative decomposition efficiency of decomposable organic matter can be improved. Therefore, it is possible to reduce the amount of ozonated water used, and it is expected that the power consumption for generating ozone in the ozone gas generator 32 will be reduced, and the running costs such as raw material gas costs will be reduced. It should be noted that the effect of improving the membrane cleaning efficiency by using two types of cleaning agents is extremely large, and the amount of ozone water used is also reduced. The effect of cost reduction by using a kind of cleaning agent is greater. Further, if a problem occurs in the ozone gas generator 32 or the ozone water generator 34 due to some influence and the cleaning operation with the ozone water is stopped, it is also possible to deal with it by cleaning with a sodium hypochlorite solution as a backup. , contributes to ensuring redundancy of the ozone water production apparatus 100i.

<Modification>
The configurations and operations shown in the above first to eleventh embodiments may be combined as appropriate. For example, the configuration and operation for using filtered water as dissolved water described in the second embodiment may be applied to the water treatment apparatuses described in the third to eleventh embodiments. Also, the configuration and operation for reusing ozone gas described in the third embodiment may be applied to the water treatment apparatuses described in the fourth to eleventh embodiments. The configuration and operation using two kinds of cleaning agents described in the eleventh embodiment may be applied to the water treatment apparatuses described in the second to tenth embodiments. Combinations of embodiments other than these are also applicable as appropriate.

Further, the ozone water production apparatus described in Embodiments 1 to 11 can be used not only for cleaning the separation membrane in the water treatment apparatus, but also as a reaction apparatus for ozone gas and a liquid containing solids such as sewage sludge, paper pulp, etc. It can also be applied to

The configurations shown in the above embodiments are only examples, and can be combined with other known techniques, or can be combined with other embodiments, without departing from the scope of the invention. It is also possible to omit or change part of the configuration.

1a Water to be treated pipe 2a Filtered water pipe 2b Discharge pipe 3a Oxygen gas pipe 3b Other gas pipe 3c Ozone gas pipe 3d Membrane cleaning pipe 3e Water to be dissolved pipe 3f Exhaust ozone gas pipe 3g Oxygen recycling pipe , 3h, 3i, 3j, 3k circulation pipe, 3m ozone water pipe, 3n sodium hypochlorite solution pipe, 10 treatment tank, 11 separation membrane, 20 membrane state measurement unit, 21, 53 switching valve, 22 process control unit, 23 filtered water pump, 25 regulating valve, 26 water to be dissolved storage tank, 30 oxygen gas supply unit, 31 other gas supply unit, 32 ozone gas generation unit, 33 ozone injection unit, 34, 34a ozone water generation unit, 35 ozone water state Measurement unit 36 Ozonated water pump 37 Condition control unit 38 Exhaust ozone treatment device 39 Circulation fan 40 Ozone gas concentration storage unit 41 Circulation fan 42, 44, 46, 50 Circulation pump 43 Ejector 45 Barrier 47 membrane module, 48, 49 fine bubble generator, 51 sodium hypochlorite solution supply unit, 52 pump, 100, 100a, 100b, 100c, 100d, 100e, 100f, 100g, 100h, 100i ozone water production device.

Claims (17)

a first gas supply unit for supplying a first gas containing oxygen gas;
a second gas supply unit for supplying a second gas containing at least one of carbon dioxide gas, nitrogen gas and nitrogen oxide gas;
Discharge for generating a third gas containing ozone gas by subjecting a gas containing the first gas supplied by the first gas supply unit and the second gas supplied by the second gas supply unit to a discharge treatment. Department and
an ozonated water generator that generates ozonized water by dissolving the third gas in water to be dissolved;
a control unit that controls the amount of by-products produced by subjecting the second gas to the discharge treatment so as to maintain acidic conditions for suppressing self-decomposition of dissolved ozone in the ozonated water;
An ozonated water production device comprising: The ozone water producing apparatus according to claim 1 , wherein the control unit controls the production amount by adjusting the flow rate of the second gas supplied from the second gas supply unit. The ozone water producing apparatus according to claim 1 or 2 , wherein the control unit controls the amount of generation by adjusting discharge conditions in the discharge process. 4. The apparatus for producing ozone water according to claim 3 , wherein said discharge condition is at least one of gas pressure, temperature, current, voltage and discharge power in said discharge treatment. an ozonated water state measuring unit that measures an amount indicating a state related to the pH of the ozonated water;
with
The ozonated water producing apparatus according to any one of claims 1 to 4 , wherein the control unit controls the production amount based on the measured value measured by the ozonated water condition measuring unit. 6. The ozonated water producing apparatus according to claim 5 , wherein the ozonated water state measuring unit measures the pH of the ozonated water. 6. The ozonated water producing apparatus according to claim 5 , wherein the ozonated water state measuring unit measures the concentration of dissolved ozone in the ozonized water. The ozone water producing apparatus according to any one of claims 5 to 7 , wherein the control unit controls the amount of production so that the measured value is within a predetermined range. 9. The ozonated water production according to any one of claims 1 to 8 , wherein the third gas that is not dissolved in the water to be dissolved in the ozonated water producing part is introduced into the ozonized water producing part. Device. an ozone gas separation unit for separating ozone gas and oxygen gas in the third gas;
with
The ozone gas separated by the ozone gas separation unit is introduced into the ozone water generation unit,
The ozone water production apparatus according to any one of claims 1 to 9 , wherein the oxygen gas separated by the ozone gas separation section is introduced into the discharge section. The ozonated water producing apparatus according to any one of claims 1 to 10 , wherein the water to be dissolved and the ozone gas are in countercurrent contact with each other in the ozonized water producing section. a fine bubble generator that introduces the third gas into the ozone water generator as fine bubbles;
The ozonated water production apparatus according to any one of claims 1 to 10 , comprising: The ozonated water producing apparatus according to any one of claims 1 to 10 , wherein the ozonized water generator is a membrane module having a porous membrane. The ozone water is used as a cleaning agent for cleaning the separation membrane that performs solid-liquid separation in a water treatment apparatus that purifies water to be treated by a membrane separation activated sludge method,
The ozone water producing apparatus according to any one of claims 1 to 13 , wherein the water to be dissolved is filtered water filtered by the separation membrane. a sodium hypochlorite solution supply unit that supplies a sodium hypochlorite solution;
with
15. The ozone water producing apparatus according to claim 14 , wherein the cleaning agent supplied to the separation membrane can be switched between the ozone water and the sodium hypochlorite solution. A water treatment apparatus equipped with a separation membrane that performs solid-liquid separation and purifying water to be treated by a membrane separation activated sludge method,
Equipped with the ozone water production apparatus according to any one of claims 1 to 13 ,
A water treatment device, wherein the separation membrane is washed with the ozone water produced by the ozone water production device. a first gas supply step of supplying a first gas containing oxygen gas;
a second gas supply step of supplying a second gas containing at least one of carbon dioxide gas, nitrogen gas and nitrogen oxide gas;
Discharge for generating a third gas containing ozone gas by subjecting a gas containing the first gas supplied by the first gas supply step and the second gas supplied by the second gas supply step to a discharge treatment. process and
an ozone water generating step of generating ozone water by dissolving the third gas in water to be dissolved;
a control step of controlling the production amount of by-products obtained by subjecting the second gas to the discharge treatment so as to maintain acidic conditions for suppressing self-decomposition of dissolved ozone in the ozonated water;
A method for producing ozonated water, comprising:

Images