JP7408371B2 - Water treatment systems and methods - Google Patents

Description

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

BACKGROUND ART Water treatment using a combination of an oxidation promoter such as hydrogen peroxide and ozone has been studied.

Japanese Patent Application Publication No. 10-99878 Japanese Patent Application Publication No. 2005-87813

In the water treatment mentioned above, it is desirable to better control the amount of pro-oxidant and ozone injected to reduce the risk of producing bromate, which is a byproduct of ozone disinfection. ing.

The water treatment system according to the embodiment includes a treatment tank, an oxidation promoter injection section, an ozone injection section, at least one of a raw water measurement section and a treated water measurement section, a dissolved ozone measurement section, and a control section. Be prepared. Water to be treated is introduced into the treatment tank. The oxidation promoter injection unit injects an oxidation promoter into the water to be treated before or after introduction into the treatment tank. The ozone injection unit brings ozone into contact with the water to be treated flowing within the treatment tank and into which the oxidation promoter has been injected. The raw water measurement unit measures the fluorescence intensity or absorbance of the water to be treated before it is introduced into the treatment tank. The treated water measurement unit measures the fluorescence intensity or absorbance of the water to be treated from the start of contact with ozone to the end of contact. The dissolved ozone measurement unit measures the dissolved ozone concentration of the water to be treated from the start of contact with ozone to the end of contact. The control unit controls the amount of oxidation promoter injected by the oxidation promoter injection unit and the ozone injection unit based on the measurement result of at least one of the raw water measurement unit and the treated water measurement unit and the measurement result of the dissolved ozone measurement unit. controlling at least one of the ozone injection amounts.

FIG. 1 is an exemplary and schematic diagram showing the configuration of a water treatment system according to a first embodiment. FIG. 2 is an exemplary and schematic graph showing the relationship between the injection amount of ozone and oxidation promoter and the fluorescence intensity according to the first embodiment. FIG. 3 is an exemplary and schematic graph showing the relationship between the ozone injection rate and the dissolved ozone concentration according to the first embodiment. FIG. 4 is an exemplary and schematic diagram showing the configuration of the water treatment system according to the second embodiment. FIG. 5 is an exemplary and schematic diagram showing the configuration of a water treatment system according to the third embodiment. FIG. 6 is an exemplary and schematic diagram showing the configuration of a water treatment system according to the fourth embodiment. FIG. 7 is an exemplary and schematic diagram showing the configuration of the water treatment system according to the fifth embodiment. FIG. 8 is an exemplary and schematic diagram showing the configuration of a water treatment system according to the sixth embodiment. FIG. 9 is an exemplary and schematic diagram showing the configuration of the water treatment system according to the seventh embodiment.

Embodiments of the present disclosure will be described below based on the drawings. The configuration of the embodiment described below, and the actions and results (effects) brought about by the configuration are merely examples, and are not limited to the contents described below.

<First embodiment>
FIG. 1 is an exemplary and schematic diagram showing the configuration of a water treatment system 1 according to the first embodiment.

The water treatment system 1 according to the first embodiment is used, for example, to purify tap water in a water purification plant. Note that the technology of the first embodiment can be used not only for the treatment of tap water but also for the treatment of sewage, and can also be used for fields such as industrial drainage and swimming pools.

As shown in FIG. 1, the water treatment system 1 according to the first embodiment includes a treatment tank 2, an oxidation promoter injection section 3, an ozone injection section 4, and a control device 10.

The treatment tank 2 is a tank into which water to be treated, which is water to be treated, is introduced. The oxidation promoter injector 3 injects an oxidation promoter into the water to be treated before or after introduction into the treatment tank 2 . The ozone injection unit 4 is installed in the treatment tank 2 and brings ozone into contact with the water to be treated flowing within the treatment tank 2 into which the oxidation promoter has been injected.

The control device 10 includes a raw water measurement section 15, a treated water measurement section 16, a dissolved ozone measurement section 17, a treatment target substance measurement section 18, and a control section 10a.

The raw water measurement unit 15 measures the fluorescence intensity of the water to be treated before it is introduced into the treatment tank 2 . The treated water measurement unit 16 measures the fluorescence intensity of the water to be treated from the start of contact with ozone to the end of contact. In the following, a configuration in which the raw water measurement unit 15 and the treated water measurement unit 16 measure fluorescence intensity will be described, but the technology of the first embodiment is applicable to a configuration in which the raw water measurement unit 15 and the treated water measurement unit 16 measure absorbance. also holds true.

The dissolved ozone measurement unit 17 measures the dissolved ozone concentration of the water to be treated from the start of contact with ozone to the end of contact. The treatment target substance measurement unit 18 measures the treatment target substance concentration, which indicates the concentration of the treatment target substance in the treatment water.

The control unit 10a controls the injection of the oxidation promoter by the oxidation promoter injection unit 3 based on the measurement result of at least one of the raw water measurement unit 15 and the treated water measurement unit 16 and the measurement result of the dissolved ozone measurement unit 17. At least one of the ozone injection amount and the ozone injection amount by the ozone injection unit 4 is controlled.

The above configuration will be described in more detail below.

The treatment tank 2 is a tank that accepts the introduction of the water to be treated and temporarily stores the water to be treated so that the introduced water to be treated is brought into contact with ozone. In the first embodiment, the treatment tank 2 is divided into two tanks, and each tank is configured to bring ozone into contact with the water to be treated.

More specifically, the treatment tank 2 is provided with an inflow section 2a into which the water to be treated flows, and an outflow section 2b through which the water to be treated flows out. Furthermore, the processing tank 2 is provided with two divided processing tanks 2c and 2d. The divided treatment tanks 2c and 2d are connected via a connecting channel 2e. The connecting channel 2e is separated from the divided treatment tanks 2c and 2d by a partition wall 2f. The water to be treated that has flowed into the treatment tank 2 from the inflow portion 2a flows out of the treatment tank 2 from the outflow portion 2b via the divided treatment tank 2c, the connection channel 2e, and the divided treatment tank 2d.

In the treatment tank 2, the oxidation promoter and ozone react in the water to be treated to generate OH radicals, and the OH radicals proceed to decompose the substance to be treated in the water to be treated. In the first embodiment, it is assumed that the substance to be treated is an organic substance, for example, an odor substance such as a musty odor substance.

The oxidation promoter injection unit 3 is a supply unit that supplies an oxidation promoter, such as hydrogen peroxide, to the water to be treated. In the example shown in FIG. 1, the oxidation promoter injector 3 is configured to supply the oxidation promoter to the water to be treated before being introduced into the treatment tank 2. The oxidation promoter injection section 3 is connected to the control section 10a. Therefore, the amount of oxidation promoter injected into the water to be treated is controlled under instructions from the control unit 10a.

The ozone injection section 4 includes an aeration section 4a, a pipe 4b, and an ozone generator 4c. One air diffuser 4a is installed in each of the divided treatment tanks 2c and 2d. The air diffuser 4a is configured, for example, as an air diffuser pipe or an air diffuser plate. Note that the air diffuser 4a may be configured as an injector, for example, as long as it is configured to introduce bubble-like gas into the water to be treated.

The air diffuser 4a is connected to an ozone generator 4c via a pipe 4b. In the first embodiment, as a result of the fluid containing ozone generated in the ozone generator 4c being sent to the aeration section 4a via the pipe 4b, ozone is injected from the aeration section 4a into the water to be treated. Note that the ozone generator 4c is connected to the control section 10a. Therefore, the amount of ozone injected into the water to be treated is controlled under instructions from the control unit 10a.

The ozone-containing bubbles injected from the air diffuser 4a rise in each of the divided treatment tanks 2c and 2d and come into contact with the water to be treated. The water to be treated comes into contact with ozone in the divided treatment tank 2c, and then comes into contact with ozone in the divided treatment tank 2d. Therefore, in the first embodiment, ozone comes into contact with the water to be treated twice in the treatment tank 2.

In addition, in the first embodiment, the first contact of the water to be treated with ozone in the divided treatment tank 2c is expressed as "start of contact with ozone", and the time when the water to be treated in the divided treatment tank 2d no longer comes into contact with ozone. This can be expressed as "the end of ozone contact."

Furthermore, in the first embodiment, the entire area where the air diffuser 4a is installed can be expressed as an "ozone contact area." The ozone contact area ranges from the position where ozone contact begins to the position where ozone contact ends. Note that the area between the air diffusers 4a is also included in the ozone contact area. That is, in the first embodiment, the connecting flow path 2e is also included in the ozone contact area.

The raw water measurement unit 15 is a sensor that measures the fluorescence intensity of the water to be treated. The raw water measuring section 15 is installed outside the treatment tank 2 and upstream of the inflow section 2a, and measures the fluorescence intensity of the water to be treated before being introduced into the treatment tank 2. Since the installation position of the raw water measurement unit 15 is upstream of the installation position of the oxidation promoter injection unit 3, the measurement target of the raw water measurement unit 15 is the water to be treated before injection of the oxidation promoter. Thereby, the raw water measurement unit 15 can measure the fluorescence intensity of the water to be treated before being affected by the oxidation promoter. Note that the measurement results of the raw water measuring section 15 are notified to the control section 10a.

The treated water measuring section 16 is also a sensor that measures the fluorescence intensity of the water to be treated, similar to the raw water measuring section 15. The treated water measurement unit 16 is installed in the connection channel 2e, and is configured to measure the fluorescence intensity of the water to be treated flowing through the connection channel 2e. The water to be treated flowing through the connection flow path 2e is the water to be treated between the start of contact with ozone and the end of contact, so the measurement target of the treated water measurement unit 16 is the water between the start of contact with ozone and the end of contact. The water to be treated is Note that the measurement results of the treated water measuring section 16 are notified to the control section 10a.

In this way, the raw water measurement section 15 and the treated water measurement section 16 are configured as a fluorescence intensity meter, which is a sensor that measures fluorescence intensity. When the raw water measuring section 15 and the treated water measuring section 16 are configured as fluorometers, the raw water measuring section 15 and the treated water measuring section 16 measure the fluorescence intensity by irradiating the water to be measured with excitation light.

In the water supply process, the fluorescence intensity corresponding to naturally occurring organic substances called fulvic acid-like organic substances is the fluorescence intensity at a wavelength of 420 to 460 nm for excitation light at a wavelength of 320 to 360 nm, especially at a wavelength of around 425 nm for excitation light at a wavelength of around 345 nm. It is desirable to measure the fluorescence intensity of The fluorescence intensity is correlated with E260 (absorbance), TOC (Total Organic Carbon), and trihalomethane production ability, which are typical indicators of organic matter concentration. Note that in the first embodiment, when absorbance is used instead of fluorescence intensity, the measurement wavelength of the absorbance meter for measuring absorbance is set to, for example, 250 to 270 nm.

The dissolved ozone measurement unit 17 is a sensor that measures the dissolved ozone concentration of the water to be treated. The dissolved ozone measurement unit 17 is installed in the connection channel 2e, and is configured to measure the dissolved ozone concentration of the water to be treated flowing through the connection channel 2e. The water to be treated flowing through the connection flow path 2e is the water to be treated between the start of contact with ozone and the end of contact, so the dissolved ozone measuring section 17 measures the water between the start of contact with ozone and the end of contact. The water to be treated is Note that the measurement results of the dissolved ozone measurement section 17 are notified to the control section 10a.

Here, in the first embodiment, the treated water measuring section 16 and the dissolved ozone measuring section 17 define the time required for the water to be treated to pass through the ozone contact area, that is, the time from the start of contact with ozone to the end of contact as T. In some cases, it is preferable that it be placed at a position corresponding to any time within the range of 0T to 0.6T. More specifically, when two air diffusers 4a are provided as in the first embodiment, the treated water measuring section 16 measures the amount of time corresponding to any time within the range of 0.4T to 0.6T. Preferably, it is located at a certain position. In the example shown in FIG. 1, the treated water measurement section 16 and the dissolved ozone measurement section 17 are arranged in the connection channel 2e provided at a position corresponding to a time within the range of 0.4T to 0.6T. , is appropriate.

However, if the positions of the treated water measuring section 16 and the dissolved ozone measuring section 17 overlap with the position of the aeration section 4a, the ozone-containing bubbles output from the aeration section 4a will reach the treated water measuring section 16 and the dissolved ozone measuring section. It is preferable that the treated water measuring section 16 and the dissolved ozone measuring section 17 are arranged at positions that do not overlap with the aeration section 4a, since this may interfere with the measurement by the section 17.

In the first embodiment, the treated water measuring section 16 and the dissolved ozone measuring section 17 are arranged at the above-mentioned positions, making it possible to obtain appropriate measurement results without being affected by bubbles containing ozone. Become. As a result, as will be described later, it becomes possible to appropriately control the injection amounts of the oxidation promoter and ozone.

The control unit 10a calculates the residual rate of fluorescence intensity based on the measurement results of the raw water measuring unit 15 and the treated water measuring unit 16, and controls the oxidation by the oxidation promoter injection unit 3 based on the comparison result between the residual rate and the threshold value. It is configured such that at least one of the amount of promoter injection and the amount of ozone injection by the ozone injection unit 4 can be controlled. Furthermore, the control unit 10a determines whether the amount of oxidation promoter injected by the oxidation promoter injection unit 3 or the amount of ozone injected by the ozone injection unit 4 is determined based on the comparison result between the measurement result of the dissolved ozone measurement unit 17 and the threshold value. The configuration is such that it is also possible to control at least one of them. Note that the operation of the control unit 10a will be described in detail in the description of the water treatment method.

Next, a water treatment method using the water treatment system 1 according to the first embodiment will be explained.

The water treatment method according to the first embodiment includes an oxidation promoter injection step, an ozone injection step, a raw water measurement step, a treated water measurement step, a dissolved ozone measurement step, and a control step.

The oxidation promoter injection step is a step in which the oxidation promoter injection unit 3 injects the oxidation promoter into the water to be treated before (or after) introduction into the treatment tank 2 . Further, the ozone injection step is a step in which the ozone injection unit 4 brings ozone into contact with the water to be treated flowing within the treatment tank 2 into which the oxidation promoter has been injected.

The raw water measuring step is a step in which the raw water measuring unit 15 measures the fluorescence intensity of the water to be treated before it is introduced into the treatment tank 2. Further, the treated water measurement step is a step in which the treated water measurement unit 16 measures the fluorescence intensity of the water to be treated from the start of contact with ozone to the end of contact.

Further, the dissolved ozone measurement step is a step in which the dissolved ozone measurement unit 17 measures the dissolved ozone concentration of the water to be treated from the start of contact with ozone to the end of contact. In addition, in the control step, the control unit 10a controls the amount of oxidation promoter injected by the oxidation promoter injection unit 3 or ozone This is a step of controlling at least one of the amounts of ozone injected by the injection unit 4.

Hereinafter, the above-mentioned steps will be explained in more detail.

First, in the raw water measuring step, the raw water measuring unit 15 measures the fluorescence intensity of the water to be treated before it is introduced into the treatment tank 2 . Note that the treated water is, for example, treated water after turbidity components have been removed in a settling tank of a water purification plant.

In the oxidation promoter injection step, the oxidation promoter injection unit 3 injects an oxidation promoter, such as hydrogen peroxide, into the water to be treated. The water to be treated into which the oxidation promoter has been injected is introduced from the inflow portion 2a of the treatment tank 2 into the divided treatment tank 2c. Then, in the ozone injection step, the ozone injection section 4 injects ozone generated from the ozone generator 4c into the water to be treated in the divided treatment tank 2c via the pipe 4b and the air diffuser 4a. The injected ozone generates OH radicals by reacting with the oxidation promoter, and the OH radicals decompose the substance to be treated in the water to be treated in the divided treatment tank 2c.

Note that, considering the properties of the substances to be treated (for example, mold odor and trihalomethane precursors in water treatment), the ratio of the amount of hydrogen peroxide injected to the amount of ozone injected is preferably about 1 to 5 in terms of molar ratio. When there is a high risk of producing bromate, which is a byproduct during disinfection with ozone, bromate can be produced by increasing the proportion of hydrogen peroxide within a molar ratio of about 1 to 5. Risk can be reduced.

The water to be treated treated in the divided treatment tank 2c is sent from the divided treatment tank 2c to the connection channel 2e. Then, in the treated water measurement step, the treated water measurement unit 16 measures the fluorescence intensity of the water to be treated in the connection channel 2e. Furthermore, in the dissolved ozone measurement step, the dissolved ozone measurement unit 17 measures the dissolved ozone concentration of the water to be treated in the connection channel 2e.

The water to be treated is then sent to the divided treatment tank 2d from the connection channel 2e. Assuming that a necessary and sufficient amount of hydrogen peroxide has been injected into the water to be treated in advance in the oxidation promoter injection step, hydrogen peroxide remains in the water to be treated that is sent to the subsequent divided treatment tank 2d. There will be. On the other hand, it is thought that most of the ozone injected into the first-stage divided treatment tank 2c has been decomposed by hydrogen peroxide, so by the time it is sent to the second-stage divided treatment tank 2d, dissolved water in the water to be treated It is thought that the ozone concentration has decreased considerably.

Ozone is injected into the water to be treated in the divided treatment tank 2d in the ozone injection step, similarly to the water to be treated in the previous divided treatment tank 2c. The injected ozone generates OH radicals by reacting with the oxidation promoter, and the OH radicals decompose the substance to be treated remaining in the water to be treated.

Next, the control steps will be explained. In the first embodiment, hydrogen peroxide and ozone can be stably injected without excess or deficiency by the method described below.

In the control step, the fluorescence intensity measured in the raw water measurement step and the treated water measurement step and the dissolved ozone concentration measured in the dissolved ozone measurement step are input to the control unit 10a. Then, the control unit 10a first calculates the residual rate of fluorescence intensity based on the fluorescence intensity measured in the raw water measurement step and the treated water measurement step. The residual rate of fluorescence intensity is calculated, for example, by the following formula.

Fluorescence intensity residual rate = FLout1/FLin

In the above formula, FLin corresponds to the fluorescence intensity measured in the raw water measurement step, and FLout1 corresponds to the fluorescence intensity measured in the treated water measurement step.

If the residual rate calculated by the above formula is less than a predetermined threshold value as the lower limit of the residual rate, the control unit 10a controls the amount of oxidation promoter injected by the oxidation promoter injection unit 3 and the ozone injection unit 4. Control is performed to reduce at least one of the ozone injection amounts. On the other hand, if the residual rate calculated by the above formula exceeds a predetermined threshold value as the upper limit of the residual rate, the control unit 10a increases at least one of the oxidation promoter injection amount and the ozone injection amount. Executes control to

If it is appropriate to keep the molar ratio of ozone and hydrogen peroxide constant, for example, the molar ratio can be kept constant by increasing or decreasing both the oxidation promoter injection amount and the ozone injection amount. control is executed. In this case, both the amount of hydrogen peroxide and the amount of ozone injected may be increased or decreased while maintaining the molar ratio of ozone and hydrogen peroxide within an appropriate range, or only the amount of ozone injected may be increased or It is also conceivable that control to reduce the amount is performed.

Here, the reason why the fluorescence intensity of the water to be treated during ozone injection is used as an index for controlling the water treatment system 1 will be explained. In the treatment tank 2, the substances to be treated are decomposed by OH radicals generated by the injected ozone and hydrogen peroxide, but at this time, as shown in Figure 2 below, the natural substances present in the water to be treated are Since the derived organic matter is also decomposed at the same time, the fluorescence intensity value becomes smaller.

FIG. 2 is an exemplary and schematic graph showing the relationship between the injection amount of ozone and oxidation promoter and the fluorescence intensity according to the first embodiment.

In the example shown in FIG. 2, the horizontal axis corresponds to the injection amounts of ozone and hydrogen peroxide, and the vertical axis corresponds to the fluorescence intensity. In the first embodiment, ozone is injected from the two air diffusers 4a, and the amount of ozone injected in the example shown in FIG. 2 means the total amount injected from the two air diffusers 4a. In the example shown in FIG. 2, FLout1 shown by a solid line corresponds to the fluorescence intensity measured in the treated water measurement step, as described above, and FLout2 shown by a broken line corresponds to the fluorescence intensity measured at the outflow part 2b of the divided treatment tank 2d. This corresponds to the fluorescence intensity of the treated water measured near . The fluorescence intensity when the injection amounts of ozone and hydrogen peroxide are 0 is the fluorescence intensity (FLin above) measured in the raw water measurement step.

As shown in FIG. 2, the values of both FLout1 and FLout2 become smaller as the amount of ozone and hydrogen peroxide injected increases. Since FLout1 is the fluorescence intensity in the middle of the treatment with ozone and hydrogen peroxide, its value is larger than FLout2, which indicates the fluorescence intensity at the end of the treatment. Also, the slope of the curve for FLout2 becomes smaller when the value on the horizontal axis exceeds "X1," but the slope of the curve for FLout1 decreases even when the value on the horizontal axis exceeds "X1." It can be said that the value is not as small as the slope of , and becomes small when the value on the horizontal axis exceeds "X2".

Here, the ratio of FLout1 to FLin is assumed to be FL survival rate 1 (FL survival rate 1=FLout1/FLin). Further, the ratio of FLout2 to FLin is set as FL survival rate 2 (FL survival rate 2=FLout2/FLin). The relationship between the FL residual rate 1 and the FL residual rate 2 and the ozone injection amount and hydrogen peroxide injection amount shows the same tendency as the above-mentioned curves FLout1 and FLout2. Furthermore, the FL residual rate 1 and the FL residual rate 2 have a corresponding relationship with the remaining amount of the object to be treated in the water to be treated.

The status of the accelerated oxidation treatment in the entire treatment tank 2 can be grasped from FLout2 corresponding to the above FL residual rate 2 near the outflow portion 2b of the divided treatment tank 2d. When the purpose is to remove mold odor in water treatment, it is desirable that the FL residual rate 2 is maintained at about 0.1 to 0.2.

However, as is clear from the above relationship between ozone injection amount, hydrogen peroxide injection amount, and FLout2, ozone and hydrogen peroxide injection The amount of change in FL residual rate 2 with respect to the amount is small. Therefore, if the FL residual rate 2 is used as an index for controlling the injection amounts of ozone and hydrogen peroxide, changes in the FL residual rate 2 may be overlooked.

Therefore, in the first embodiment, the FL residual rate 1 can be employed as one of the indicators for controlling the injection amounts of ozone and hydrogen peroxide. Since the connecting flow path 2e is a region through which the water to be treated in the middle stage of the reaction passes, the FL residual rate 1 corresponding to the region has not been sufficiently reduced. Therefore, it can be said that the FL residual rate 1 is more suitable as an index for controlling the injection amounts of ozone and hydrogen peroxide than the FL residual rate 2, since its change is difficult to overlook.

In the first embodiment, the control unit 10a calculates the FL residual rate 1 based on the fluorescence intensity measured in the raw water measuring step and the treated water measuring step, and determines whether this FL residual rate 1 is a predetermined target value (target value). The injection amounts of ozone and hydrogen peroxide are controlled by feedback control so that the FL residual rate is 1).

Furthermore, in addition to the FL residual rate 1, the first embodiment may employ the dissolved ozone concentration measured in the above-described dissolved ozone measurement step as an index for controlling the injection amounts of ozone and hydrogen peroxide. As mentioned above, most of the ozone injected into the split treatment tank 2c is decomposed by hydrogen peroxide, so by the time it is sent to the split treatment tank 2d, the dissolved ozone concentration has decreased considerably. Conceivable. However, when the concentration of the substance to be treated is high in the raw water, which is the water to be treated before being introduced into treatment tank 2, it is necessary to inject more ozone and hydrogen peroxide to decompose the substance to be treated. becomes. In such a situation, the dissolved ozone concentration increases to a level that can be sufficiently measured, and therefore can be used as an indicator for control.

As shown in FIG. 3, the dissolved ozone concentration is measured after the reaction in the divided treatment tank 2c (that is, in the connecting channel 2e) or after the reaction in the divided treatment tank 2d (that is, in the outflow section). 2b), the values are almost the same. Therefore, in the first embodiment, for quick feedback control, the dissolved ozone concentration of the water to be treated measured within the connection channel 2e can be used as a control index.

FIG. 3 is an exemplary and schematic graph showing the relationship between the ozone injection rate and the dissolved ozone concentration according to the first embodiment.

In the example shown in FIG. 3, the horizontal axis corresponds to the injection amount of ozone/hydrogen peroxide, and the vertical axis corresponds to the dissolved ozone concentration. Moreover, the values plotted with black □ correspond to the dissolved ozone concentration of the water to be treated in the connection channel 2e when both ozone and hydrogen peroxide are injected, and the values plotted with △ correspond to the concentration of dissolved ozone in the water to be treated in the case where both ozone and hydrogen peroxide are injected. This corresponds to the dissolved ozone concentration of the water to be treated near the outflow portion 2b when both hydrogen peroxide and hydrogen peroxide are injected. Note that the values plotted with ◇ correspond to the dissolved ozone concentration of the water to be treated in the connecting channel 2e when ozone is injected alone, which is shown for comparison.

As shown in FIG. 3, whether both ozone and hydrogen peroxide are injected or ozone alone is injected, the dissolved ozone concentration basically increases depending on the injection amount. Therefore, it can be said that it is appropriate to employ the dissolved ozone concentration as an index for controlling the injection amounts of ozone and hydrogen peroxide.

Furthermore, as can be seen by comparing the values plotted with black □ and the values plotted with △, the dissolved ozone concentration is determined regardless of whether it is measured in the connecting channel 2e or near the outflow section 2b. , almost unchanged. This is because the remaining hydrogen peroxide consumes ozone near the outflow portion 2b as well as in the connecting channel 2e. For rapid feedback control, it can be said that the dissolved ozone concentration measured within the connecting channel 2e is more appropriate as a control index than the dissolved ozone concentration measured near the outflow portion 2b.

Based on the above, the method of controlling the injection amount of ozone and hydrogen peroxide using the residual rate of fluorescence intensity (FL residual rate 1) as a control indicator is suitable when the concentration of the target substance to be treated in raw water is not very high. It can be said that it is a method. However, when the concentration of the target substance in raw water is high, even if more ozone and hydrogen peroxide are injected for decomposition, the FL residual rate 1 is small, so the injection of ozone and hydrogen peroxide Since the change in the FL remaining rate 1 in response to the change in amount becomes small, it becomes difficult to use the FL remaining rate 1 as an index for control.

Therefore, in the first embodiment, the control unit 10a performs first control to control the injection amount of the oxidation promoter and ozone based on the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16, and the dissolved ozone measurement unit. 17, the measurement results of the raw water measurement section 15 and the treated water measurement section 16, and the measurement results of the dissolved ozone measurement section 17. A third control that controls the injection amount of the oxidation promoter and ozone based on both can be selectively performed.

In the first embodiment, the control unit 10a switches between the first control, the second control, and the third control based on the measurement results of the treatment target substance measurement unit 18, the raw water measurement unit 15, and the treated water. It can be executed according to at least one of the measurement results of the measurement section 16 and the measurement results of the dissolved ozone measurement section 17.

More specifically, in the first embodiment, when the concentration of the substance to be treated in the raw water is low, the control unit 10a employs the FL residual rate 1 as a control index, and performs feedback control according to the FL residual rate. It can be done. In addition, when the concentration of the substance to be treated in the raw water is high, the control unit 10a uses the dissolved ozone concentration as a control index in addition to the FL residual rate 1, and sets the upper and lower limits of the dissolved ozone concentration. It is also possible to perform control to suppress over-injection of hydrogen peroxide.

For example, in the first embodiment, when the concentration of 2-MIB, which is an example of a musty-smelling substance in raw water, is within the range of 50 to 100 ng/L, the control unit 10a uses the FL residual rate 1 as the control index. If the concentration is higher than that, control can be performed in which the dissolved ozone concentration is also used as a control index in addition to the FL residual rate 1.

As described above, considering the properties of the substance to be treated, the ratio of the amount of hydrogen peroxide to the amount of ozone to be injected may be about 1 to 5 in terms of molar ratio. Therefore, in the first embodiment, the control unit 10a can control the injection amounts of ozone and hydrogen peroxide, for example, while fixing the molar ratio to around 1 in order to prevent excessive injection of hydrogen peroxide. When there is a high risk of producing bromate, which is a byproduct during disinfection with ozone, bromate can be produced by increasing the proportion of hydrogen peroxide within a molar ratio of about 1 to 5. Risk can be reduced.

In general, it is difficult to grasp the risk of bromate generation in real time, and unless there is a major change in the quality of raw water, the risk of bromate generation will not change significantly. Therefore, in the first embodiment, a method of manually setting the hydrogen peroxide ratio may be adopted, and a water quality index etc. that can grasp the risk of bromate generation can be obtained in real time. If there is a mechanism, a method may be adopted in which the ratio of hydrogen peroxide is automatically changed in conjunction with the mechanism.

In the embodiment, when completely switching the control index from FL residual rate 1 to dissolved ozone concentration, the control unit 10a adjusts the dissolved ozone concentration to a predetermined target value (target dissolved ozone concentration). Additionally, the amount of ozone and hydrogen peroxide injected can be controlled.

As a result of intensive research, the inventors of the present application confirmed that the musty odor substance as a treatment target substance and the fluorescence intensity decrease at almost the same rate, so the residual rate of fluorescence intensity (FL residual rate 1) was It is known that the concentration of the substance to be treated can be reduced to the target concentration according to the control used as an index.

However, if the concentration of the target substance in the raw water is high, or if the target concentration of the target substance needs to be set low, it is necessary to increase the injection amount of ozone and oxidation promoter until the fluorescence intensity value becomes small. Therefore, the change in fluorescence intensity with respect to the injection amount becomes small, making it unsuitable for control (see FIG. 2).

On the other hand, as the amount of ozone and oxidation promoter increases, the dissolved ozone concentration, which had been low, gradually increases until it reaches a level that can be measured sufficiently (see Figure 3).

Based on the above, in the first embodiment, the control unit 10a sets the conditions that the FL residual rate 1 is below a threshold value (for example, 20%) and that the dissolved ozone concentration is above a threshold value (for example, 0.10 mg/L). When at least one of these conditions is satisfied, the control index can be switched from the FL residual rate 1 to the dissolved ozone concentration. This makes it possible to appropriately control the injection amounts of ozone and hydrogen peroxide even when the target water quality is wide, for example.

However, if the raw water is clear and the fluorescence intensity is low to begin with, the change in FL residual rate 1 with respect to the injection amount of ozone and oxidation promoter tends to be small. Therefore, in this case, it is desirable to also use the dissolved ozone concentration as a control index. In this case, control based on the FL residual rate 1 is executed as basic control, and then control is executed to suppress excessive injection of ozone and oxidation promoter based on an appropriately set upper limit value of dissolved ozone concentration. sell.

As explained above, the water treatment system 1 according to the first embodiment includes the treatment tank 2, the oxidation promoter injection section 3, the ozone injection section 4, the raw water measurement section 15, the treated water measurement section 16, It includes a dissolved ozone measurement section 17 and a control section 10a. The oxidation promoter injector 3 injects an oxidation promoter into the water to be treated before or after introduction into the treatment tank 2 . The ozone injection unit 4 brings ozone into contact with the water to be treated flowing within the treatment tank 2 into which the oxidation promoter has been injected.

The raw water measurement unit 15 measures the fluorescence intensity of the water to be treated before it is introduced into the treatment tank. The treated water measurement unit 16 measures the fluorescence intensity of the water to be treated from the start of contact with ozone to the end of contact. The dissolved ozone measurement unit 17 measures the dissolved ozone concentration of the water to be treated from the start of contact with ozone to the end of contact.

Here, the control unit 10a determines the amount of oxidation promoter injected by the oxidation promoter injection unit 3 based on the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16, and the measurement results of the dissolved ozone measurement unit 17. and the amount of ozone injected by the ozone injector 4. Thereby, water treatment by injection of an oxidation promoter and ozone can be appropriately performed using a plurality of indicators.

More specifically, according to the above configuration, for example, a region where the amount of change in fluorescence intensity with respect to the injection amount of ozone and hydrogen peroxide is large, and a region where a change in dissolved ozone concentration can be detected are determined using different indicators. It is possible to perform control based on Therefore, it is possible to appropriately inject ozone and hydrogen peroxide from low to high concentrations of substances to be treated in raw water, reducing the risk of bromate generation while treating Target substances can be appropriately reduced.

<Second embodiment>
Next, a second embodiment will be described with reference to FIG. 4. In the example shown in FIG. 4, the components with the same reference numerals as those in the example shown in FIG. 1 are the same as those in the first embodiment, and the description thereof will be omitted.

FIG. 4 is an exemplary and schematic diagram showing the configuration of the water treatment system 21 according to the second embodiment. As described below, in the second embodiment, a processing tank 22 having a different configuration from the processing tank 2 according to the first embodiment is used. The configuration of the processing tank 22 will be mainly described below.

As shown in FIG. 4, similarly to the treatment tank 2 according to the first embodiment, the treatment tank 22 according to the second embodiment receives the introduction of water to be treated, and contacts the introduced water to be treated with ozone. This is a tank that temporarily stores water to be treated. However, the processing tank 22 according to the second embodiment is configured as a single processing tank without the divided processing tanks 2c and 2d as in the first embodiment.

The treatment tank 22 is provided with an inflow portion 2a into which the water to be treated flows, and an outflow portion 2b through which the water to be treated flows out. The water to be treated introduced into the treatment tank 22 from the inflow portion 2a passes through the treatment tank 22 and flows out from the outflow portion 2b. In the treatment tank 22, two air diffusers 4a are arranged along the flow direction of the water to be treated, and a treated water measuring section 16 and a dissolved ozone measuring section 17 are arranged between the two air diffusers 4a. There is.

Also in the second embodiment, as in the first embodiment described above, ozone can be brought into contact with the treated water twice in the treatment tank 22. That is, in the treatment tank 22, OH radicals are generated by the reaction between the oxidation promoter in the water to be treated and ozone in the area where the two air diffusers 4a are provided. Then, the generated OH radicals proceed to decompose the substance to be treated in the water to be treated.

Therefore, in the second embodiment as well, the same control as in the first embodiment can be executed. More specifically, the control unit 20a of the control device 20 according to the second embodiment also uses the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16 and dissolved ozone, similarly to the control unit 10a according to the first embodiment. Based on the measurement result of the measurement unit 17, at least one of the amount of oxidation promoter injected by the oxidation promoter injection unit 3 and the amount of ozone injected by the ozone injection unit 4 can be controlled.

In more detail, the control unit 20a according to the second embodiment also controls the concentration of oxidation promoter and ozone based on the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16, similarly to the control unit 10a according to the first embodiment. A first control that controls the injection amount, a second control that controls the injection amount of the oxidation promoter and ozone based on the measurement results of the dissolved ozone measurement section 17, and a second control that controls the injection amount of the raw water measurement section 15 and the treated water measurement section 16. Third control that controls the injection amount of the oxidation promoter and ozone based on both the measurement result and the measurement result of the dissolved ozone measurement unit 17 can be selectively performed.

Note that the other configurations of the second embodiment are the same as those of the first embodiment.

According to the water treatment system 21 according to the second embodiment, the same effects as those of the first embodiment described above can be obtained, and the following effects can also be obtained.

Since the treatment tank 22 of the water treatment system 21 according to the second embodiment is not partitioned by partition walls or the like, the treated water measuring section 16 and the dissolved ozone measuring section 17 can be used to measure the treated water while contacting it with ozone. Measurement results can be obtained from This makes it possible to more sensitively detect changes in measurement results with respect to the amounts of ozone and hydrogen peroxide injected, so that the amounts of ozone and hydrogen peroxide to be injected can be appropriately controlled.

<Third embodiment>
Next, a third embodiment will be described with reference to FIG. 5. In the example shown in FIG. 5, constituent elements labeled with the same reference numerals as those in the example shown in FIG. 1 are the same as those in the first embodiment, and a description thereof will be omitted.

FIG. 5 is an exemplary and schematic diagram showing the configuration of the water treatment system 31 according to the third embodiment. As explained below, in the third embodiment, a processing tank 32 having a different configuration from the processing tank 2 according to the first embodiment is used. The configuration of the processing tank 32 will be mainly described below.

As shown in FIG. 5, similarly to the treatment tank 2 according to the first embodiment, the treatment tank 32 according to the third embodiment also receives the introduction of water to be treated, and contacts the introduced water to be treated with ozone. This is a tank that temporarily stores water to be treated.
However, unlike the processing tank 2 according to the first embodiment, the processing tank 32 according to the third embodiment is configured as a single vertically long processing tank.

The treatment tank 32 is provided with an inflow portion 32a into which the water to be treated flows, and an outflow portion 32b through which the water to be treated flows out. The inflow part 32a is located at the upper part of the processing tank 32, and the outflow part 32b is located at the lower part of the processing tank 32. The water to be treated that is introduced into the treatment tank 32 from the inflow portion 32a passes through the treatment tank 32 from the top to the bottom, and flows out from the outflow portion 32b.

Further, in the third embodiment, an ozone injection section 34 having a different configuration from the ozone injection section 4 according to the first embodiment is provided. More specifically, the ozone injection unit 34 according to the third embodiment has only one air diffuser 4a arranged at the bottom of the processing tank 32.

In the example shown in FIG. 5, the air diffuser 4a is arranged further below the outflow part 32b, but the air diffuser 4a is arranged at the same height as the outflow part 32b or above the outflow part 32b. Good too. The ozone injection unit 34 according to the third embodiment injects ozone from below the processing tank 32 into the water to be treated flowing from above to below the processing tank 32 using the aeration unit 4a. As a result, the ozone-containing bubbles come into contact with the water to be treated flowing from above to below the processing tank 32 as they rise while diffusing inside the processing tank 32 .

In the third embodiment, the treated water measuring section 16 and the dissolved ozone measuring section 17 are arranged at a position between the inflow section 32a and the outflow section 32b of the treatment tank 32. If the treated water measuring section 16 and dissolved ozone measuring section 17 are installed near the aeration section 4a, bubbles containing ozone will become an obstacle to measurement. It is preferable to install it at a position away from the ozone injection part 4.

Based on the above configuration, the same control as in the first embodiment can be performed in the third embodiment as well. More specifically, the control unit 30a of the control device 30 according to the third embodiment also uses the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16 and dissolved ozone, similarly to the control unit 10a according to the first embodiment. Based on the measurement result of the measurement unit 17, at least one of the amount of oxidation promoter injected by the oxidation promoter injection unit 3 and the amount of ozone injected by the ozone injection unit 4 can be controlled.

More specifically, similarly to the control unit 10a according to the first embodiment, the control unit 30a according to the third embodiment also controls the concentration of oxidation promoter and ozone based on the measurement results of the raw water measurement unit 15 and the treated water measurement unit 16. A first control that controls the injection amount, a second control that controls the injection amount of the oxidation promoter and ozone based on the measurement results of the dissolved ozone measurement section 17, and a second control that controls the injection amount of the raw water measurement section 15 and the treated water measurement section 16. Third control that controls the injection amount of the oxidation promoter and ozone based on both the measurement result and the measurement result of the dissolved ozone measurement unit 17 can be selectively executed.

Note that the other configurations of the third embodiment are the same as those of the first embodiment.

According to the water treatment system 31 according to the third embodiment, the same effects as those of the first embodiment described above can be obtained, and the following effects can also be obtained.

According to the water treatment system 31 according to the third embodiment, only one air diffuser 4a is required to be disposed in the treatment tank 32, so the configuration of the water treatment system 31 can be simplified.

<Fourth embodiment>
Next, a fourth embodiment will be described with reference to FIG. 6. In the example shown in FIG. 6, the components denoted by the same reference numerals as those in the example shown in FIG. 1 are the same as those in the first embodiment, and a description thereof will be omitted.

FIG. 6 is an exemplary and schematic diagram showing the configuration of a water treatment system 41 according to the fourth embodiment. As explained below, in the fourth embodiment, the raw water measuring section 15 according to the first embodiment is omitted.

More specifically, as shown in FIG. 6, in the fourth embodiment, information on the water to be treated in the inflow portion 2a is measured only by the substance-to-be-treated measuring unit 18. Even with such a configuration, the control unit 40a of the control device 40 according to the fourth embodiment can perform control based on the same technical idea as the first embodiment described above.

That is, when the fluctuation in the quality of the raw water, which is the water to be treated before being introduced into the treatment tank 2, is small, the fluorescence intensity (FLout1) of the water to be treated passing through the connection channel 2e and the residual rate based on this fluorescence intensity are (FL residual rate 1) can be considered to be almost the same, so there is no need to measure the fluorescence intensity (FLin) of the raw water. Therefore, according to the fourth embodiment, the configuration of the water treatment system 41 can be simplified by omitting the raw water measuring section 15.

Note that the other configurations and operations of the fourth embodiment are substantially the same as those of the first embodiment described above.

Here, as a modification of the fourth embodiment, a configuration may be considered in which the treated water measuring section 16 is omitted and only the raw water measuring section 15 is used to execute control. More specifically, even if the variation in the quality of raw water is small, the relationship shown in FIG. 2 between the injection amounts of ozone and oxidation promoter and the fluorescence intensity hardly changes. Therefore, by inputting this relationship as a mathematical formula in advance and calculating the injection amount of ozone and oxidation promoter corresponding to the target value of the residual rate of fluorescence intensity from only the measurement results of the raw water measuring section 15, feedforward It can be said that there is a good possibility that the injection amounts of ozone and oxidation promoter can be appropriately controlled through control.

<Fifth embodiment>
Next, a fifth embodiment will be described with reference to FIG. 7. In the example shown in FIG. 7, the components with the same reference numerals as those in the example shown in FIG. 1 are the same as those in the first embodiment, and the description thereof will be omitted.

FIG. 7 is an exemplary and schematic diagram showing the configuration of a water treatment system 51 according to the fifth embodiment. As described below, the fifth embodiment differs from the first embodiment in the configuration for measuring the fluorescence intensity of the water to be treated.

As shown in FIG. 7, in the fifth embodiment, as a configuration corresponding to the raw water measurement section 15 and the treated water measurement section 16 according to the first embodiment, a raw water separation tube 55a and a treated water separation tube 55a are provided. 55b, a switching section 55c, and a water quality measuring section 55d.

One end of the raw water separation pipe 55a is connected to the inflow portion 2a so as to separate raw water, which is water to be treated, before being introduced into the treatment tank 2. Further, one end of the treated water separation pipe 55b is connected to the connecting flow path 2e so as to separate the water to be treated between the reaction in the divided treatment tank 2c and the reaction in the divided treatment tank 2d. The other end of each of the raw water separation tube 55a and the treated water separation tube 55b is connected to the switching section 55c.

The switching unit 55c connects the raw water separating pipe 55a to the water quality measuring unit so as to selectively supply the water to be treated separated by the raw water separating pipe 55a and the treated water separating pipe 55b to the water quality measuring unit 55d. It is configured as a switch for switching between connecting to the section 55d or connecting the treated water separation pipe 55b to the water quality measuring section 55d. The water quality measurement section 55d is configured as a fluorescence intensity meter (or an absorbance meter that measures absorbance) that measures the fluorescence intensity of the water to be treated supplied from the switching section 55c.

In the fifth embodiment, the switching unit 55c is configured to alternately switch the connection relationship as described above, for example, when the residence time of the water to be treated in the treatment tank 2 is longer than a predetermined time (for example, 10 minutes). has been done. Therefore, in this case, the fluorescence intensity (FLin) of the raw water and the fluorescence intensity (FLout1) of the water to be treated in the connecting flow path 2e are alternately measured by the single water quality measurement unit 55d.

In the above configuration, for example, if the unmeasured fluorescence intensity is regarded as constant until the next measurement, the fluorescence intensity of the raw water and the fluorescence intensity of the water to be treated in the connecting channel 2e can be changed. It is possible to obtain the same result as obtaining both and at the same time. Therefore, the control unit 50a of the control device 50 according to the fifth embodiment can also perform control based on the same technical idea as the first embodiment described above. However, in the fifth embodiment, it is desirable that the fluctuation in the quality of the water to be treated is not so large.

As described above, in the fifth embodiment, as a configuration for measuring the fluorescence intensity of the raw water and the fluorescence intensity of the water to be treated in the connecting channel 2e, the raw water separation tube 55a and the treated water separation tube 55a are used. A take-up pipe 55b, a switching section 55c, and a water quality measuring section 55d are used. That is, in the fifth embodiment, the raw water separation tube 55a, the switching section 55c, and the water quality measurement section 55d function as a raw water measurement section that measures the fluorescence intensity of raw water, and the treated water separation tube 55b, the switching section The section 55c and the water quality measuring section 55d function as a treated water measuring section that measures the fluorescence intensity of the water to be treated in the connecting channel 2e. Thereby, expensive measuring instruments that require maintenance can be integrated into a single water quality measuring section 55d, so the configuration of the water treatment system 51 can be simplified.

<Sixth embodiment>
Next, a sixth embodiment will be described with reference to FIG. 8. In the example shown in FIG. 8, components with the same reference numerals as those in the example shown in FIG. 1 are the same as in the first embodiment, and description thereof will be omitted.

FIG. 8 is an exemplary and schematic diagram showing the configuration of a water treatment system 61 according to the sixth embodiment. As described below, in the sixth embodiment, a processing tank 62 having a different configuration from the processing tank 2 according to the first embodiment is used. The configuration of the processing tank 62 will be mainly described below.

As shown in FIG. 8, similarly to the treatment tank 2 according to the first embodiment, the treatment tank 22 according to the sixth embodiment also receives the introduction of water to be treated, and contacts the introduced water to be treated with ozone. This is a tank that temporarily stores water to be treated. However, unlike the processing tank 2 according to the first embodiment, the processing tank 62 according to the sixth embodiment is divided into three regions.

More specifically, the treatment tank 62 according to the sixth embodiment is provided with an inflow section 62a into which the water to be treated flows, and an outflow section 62b through which the water to be treated flows out. Furthermore, the processing tank 62 is provided with three divided processing tanks 62c, 62d, and 62e.

A connecting flow path 62f is provided between the divided processing tanks 62c and 62d, and a connecting flow path 62g is provided between the divided processing tanks 62d and 62e. The connecting channels 62f and 62g are separated from the divided treatment tanks 62c, 62d, and 62e by a partition wall 62h.

The water to be treated introduced into the treatment tank 62 from the inflow part 62a passes through a divided treatment tank 62c, a connection flow path 62f, a division treatment tank 62d, a connection flow path 62g, and a division treatment tank 62e, and then flows from the outflow part 62b to the treatment tank. It is leaked to the outside of 2.

Further, in the sixth embodiment, an ozone injection section 64 having a configuration different from that of the ozone injection section 4 according to the first embodiment is provided. More specifically, the ozone injection unit 64 according to the sixth embodiment is provided with three air diffusers 4a corresponding to the divided treatment tanks 62c, 62d, and 62e.

That is, in the sixth embodiment, the air diffuser 4a is arranged at the bottom of each of the three divided treatment tanks 62c, 62d, and 62e. Therefore, in the sixth embodiment, ozone comes into contact with the water to be treated three times in the treatment tank 62.

In the sixth embodiment, the treated water measuring section 16 and the dissolved ozone measuring section 17 are configured to measure the temperature within the connecting flow path 62f between the most upstream divided treatment tank 62c and the second upstream divided treatment tank 62d. The system is configured to measure characteristics of the water to be treated. Therefore, in the sixth embodiment, similarly to the first embodiment described above, the treated water measuring section 16 and the dissolved ozone measuring section 17 measure 0T when the time from the start of ozone contact to the end of contact is T. It is placed at a position corresponding to any time within the range of ~0.6T.

In addition, in the configuration in which three air diffusers 4a are provided as in the sixth embodiment, the treated water measuring section 16 and the dissolved ozone measuring section 17 are configured to operate at any temperature within the range of 0.2T to 0.4T. Preferably, it is located at a certain position. The example shown in FIG. 8 satisfies the above condition because the connection flow path 62f corresponding to the treated water measurement section 16 and the dissolved ozone measurement section 17 is within the range of 0.2T to 0.3T.

Note that the other configurations and operations of the sixth embodiment are the same as those of the first embodiment described above. Therefore, the control unit 60a of the control device 60 according to the sixth embodiment can also perform control based on the same technical idea as the first embodiment described above. Therefore, the sixth embodiment can also provide the same effects as the first embodiment described above.

In the sixth embodiment, since the treatment tank 62 is provided with three air diffusers 4a, it is possible to easily re-inject the ozone reduced by the injection of hydrogen peroxide at a later stage.

<Seventh embodiment>
Next, a seventh embodiment will be described with reference to FIG. 9. The seventh embodiment is a modification of the sixth embodiment described above. In the example shown in FIG. 9, the components denoted by the same reference numerals as those in the example shown in FIG. 8 are the same as those in the sixth embodiment, and a description thereof will be omitted.

FIG. 9 is an exemplary and schematic diagram showing the configuration of a water treatment system 71 according to the seventh embodiment. As described below, in the seventh embodiment, a processing tank 72 having a different configuration from the processing tank 62 according to the sixth embodiment is used. The configuration of the processing tank 72 will be mainly described below.

As shown in FIG. 9, similarly to the treatment tank 62 according to the sixth embodiment, the treatment tank 72 according to the seventh embodiment receives the introduction of water to be treated, and contacts the introduced water to be treated with ozone. This is a tank that temporarily stores water to be treated. However, the processing tank 72 according to the seventh embodiment is configured as a single processing tank without the divided processing tanks 62c, 62d, and 62e as in the sixth embodiment.

More specifically, the treatment tank 72 has an inflow part 72a into which water to be treated flows, and the water to be treated introduced into the treatment tank 22 from the inflow part 2a passes through the treatment tank 22 and flows out from the outflow part 2b. leak. In the treatment tank 72, three aeration units 4a are arranged along the flow direction of the water to be treated, and the treated water measurement unit 16 and the dissolved ozone measurement unit 17 are arranged in the most upstream aeration unit 4a and the second aeration unit 4a. and the upstream air diffuser 4a.

Also in the seventh embodiment, as in the sixth embodiment described above, ozone can be brought into contact with the treated water in the treatment tank 72 three times. Therefore, the control unit 70a of the control device 70 according to the seventh embodiment can also perform control based on the same technical idea as the sixth embodiment described above.

Note that the other configurations and operations of the seventh embodiment are substantially the same as those of the sixth embodiment described above. Therefore, according to the seventh embodiment, the same effects as those of the sixth embodiment described above can be obtained, and the following effects can also be obtained.

That is, since the treatment tank 72 of the water treatment system 71 according to the seventh embodiment is not partitioned by partition walls or the like, the treated water measuring section 16 and the dissolved ozone measuring section 17 are able to measure the temperature of the water during contact with ozone. Measurement results can be obtained from treated water. This makes it possible to more sensitively detect changes in measurement results with respect to the amounts of ozone and hydrogen peroxide injected, so that the amounts of ozone and hydrogen peroxide to be injected can be appropriately controlled.

Although several embodiments of the present invention have been described above, the above embodiments are merely examples and are not intended to limit the scope of the invention. The embodiments described above can be implemented in various forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. The above-mentioned embodiments and their modifications are included within the scope and gist of the invention, and are also included within the scope of the invention described in the claims and its equivalents.

1, 21, 31, 41, 51, 61, 71 Water treatment system 2, 22, 32, 62, 72 Treatment tank 2e, 62f, 62g Connection channel 3 Oxidation promoter injection part 4 Ozone injection part 4a Diffusion part ( ozone injection part)
4b Piping (ozone injection part)
4c Ozone generator (ozone injection part)
15 Raw water measurement section 16 Treated water measurement section 17 Dissolved ozone measurement section 18 Treatment target substance measurement section 10a, 20a, 30a, 40a, 50a, 60a, 70a Control section 55a Separation tube for raw water (raw water measurement section)
55b Separation tube for treated water (treated water measuring section)
55c Switching section (raw water measurement section, treated water measurement section)
55d Water quality measurement section (raw water measurement section, treated water measurement section)

Claims (7)

A treatment tank into which water to be treated is introduced;
a control unit;
an oxidation promoter injection unit that injects an oxidation promoter into the water to be treated before or after introduction into the treatment tank;
an ozone injection unit that brings ozone into contact with the water to be treated that has been injected with the oxidation promoter flowing in the treatment tank;
a treatment target substance measuring unit that measures the concentration of a treatment target substance contained in the treatment water before introduction into the treatment tank;
a raw water measurement unit that measures the fluorescence intensity or absorbance of the water to be treated before being introduced into the treatment tank ;
a treated water measuring unit that measures the fluorescence intensity or absorbance of the treated water from the start of the contact with the ozone to the end of the contact ;
a dissolved ozone measurement unit that measures the dissolved ozone concentration of the water to be treated from the start of the contact with the ozone to the end of the contact ,
The control unit includes:
When the concentration measured by the treatment target substance measurement unit satisfies a predetermined low condition,
Determining the residual rate by dividing the measured value of the treated water measuring unit by the measured value of the raw water measuring unit,
When the residual rate is below a predetermined lower limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to reduce the injection amount of at least one of the oxidation promoter and ozone,
When the residual rate exceeds a predetermined upper limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to increase the injection amount of at least one of the oxidation promoter and ozone,
When the concentration measured by the processing target substance measurement unit satisfies a predetermined high condition,
A water treatment system that controls the amount of oxidation promoter injected by the oxidation promoter injection part and the amount of ozone injected by the ozone injection part so that the dissolved ozone concentration measured by the dissolved ozone measurement part becomes a predetermined target value. . A treatment tank into which water to be treated is introduced;
a control unit;
an oxidation promoter injection unit that injects an oxidation promoter into the water to be treated before or after introduction into the treatment tank;
an ozone injection unit that brings ozone into contact with the water to be treated that has been injected with the oxidation promoter flowing in the treatment tank;
a treatment target substance measuring unit that measures the concentration of a treatment target substance contained in the treatment water before introduction into the treatment tank;
a raw water measurement unit that measures the fluorescence intensity or absorbance of the water to be treated before being introduced into the treatment tank;
a treated water measuring unit that measures the fluorescence intensity or absorbance of the treated water from the start of the contact with the ozone to the end of the contact;
a dissolved ozone measurement unit that measures the dissolved ozone concentration of the water to be treated from the start of the contact with the ozone to the end of the contact,
The control unit includes:
When the concentration measured by the treatment target substance measurement unit satisfies a predetermined low condition,
Determining the residual rate by dividing the measured value of the treated water measuring unit by the measured value of the raw water measuring unit,
When the residual rate is below a predetermined lower limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to reduce the injection amount of at least one of the oxidation promoter and ozone,
When the residual rate exceeds a predetermined upper limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to increase the injection amount of at least one of the oxidation promoter and ozone,
When the concentration measured by the processing target substance measurement unit satisfies a predetermined high condition,
When the residual rate is below a predetermined lower limit threshold, the oxidation promoter injection part and the ozone injection part are adjusted so that the measured dissolved ozone concentration falls within the set upper and lower limits of the dissolved ozone concentration. controlling at least one to reduce the injection amount of at least one of the pro-oxidant and ozone;
When the residual rate exceeds a predetermined upper limit threshold, the oxidation promoter injection part and the ozone injection part are adjusted so that the measured dissolved ozone concentration falls within the set upper and lower limits of the dissolved ozone concentration. A water treatment system that controls at least one to increase the amount of injection of at least one of a pro-oxidant and ozone. When the range in which the ozone injection part is arranged in the treatment tank is defined as an ozone contact area, and the time required for the treated water to pass through the ozone contact area is defined as T,
The treated water measurement unit and the dissolved ozone measurement unit are arranged at positions corresponding to any time within the range of 0T to 0.6T,
The water treatment system according to claim 1 or 2 . The ozone injection unit includes a plurality of ozone injection units arranged along the flow direction of the water to be treated,
The treated water measurement unit and the dissolved ozone measurement unit are arranged between any one of the plurality of ozone injection units,
The water treatment system according to claim 1 or 2 . The treatment tank includes a plurality of divided treatment tanks arranged along the direction in which the water to be treated flows, and one or more connection channels that connect the divided treatment tanks,
The ozone injection unit includes a plurality of ozone injection units respectively provided in the plurality of divided treatment tanks,
The treated water measuring section and the dissolved ozone measuring section are arranged in any one of the one or more connecting channels,
The water treatment system according to claim 1 or 2 . The treated water measurement unit and the raw water measurement unit include a single water quality measurement unit, a raw water separation tube and a treated water separation tube that separate a part of the treated water to be measured, and the Connecting the raw water separation tube to the water quality measurement section so that the treated water separated by the raw water separation tube and the treated water separation tube is selectively supplied to the water quality measurement section. or a switching unit that switches whether to connect the treated water separation pipe to the water quality measurement unit,
The water treatment system according to claim 1 or 2 . Injecting an oxidation promoter into the water to be treated before or after introduction into the treatment tank into which the water to be treated is introduced, by an oxidation promoter injection part;
Bringing ozone into contact with the water flowing through the treatment tank into which the oxidation promoter has been injected, by an ozone injection unit;
Measuring the concentration of a treatment target substance contained in the treatment target water before introduction into the treatment tank by a treatment target substance measurement unit;
Measuring the fluorescence intensity or absorbance of the water to be treated before introduction into the treatment tank using a raw water measurement unit;
Measuring the fluorescence intensity or absorbance of the treated water from the start of the contact with the ozone to the end of the contact using a treated water measurement unit ;
Measuring the dissolved ozone concentration of the water to be treated from the start of the contact with the ozone to the end of the contact using a dissolved ozone measurement unit;
By the control section,
When the concentration measured by the treatment target substance measurement unit satisfies a predetermined low condition,
Determining the residual rate by dividing the measured value of the treated water measuring unit by the measured value of the raw water measuring unit,
When the residual rate is below a predetermined lower limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to reduce the injection amount of at least one of the oxidation promoter and ozone,
When the residual rate exceeds a predetermined upper limit threshold, controlling at least one of the oxidation promoter injection part and the ozone injection part to increase the injection amount of at least one of the oxidation promoter and ozone. and,
When the concentration measured by the processing target substance measurement unit satisfies a predetermined high condition,
Controlling the amount of oxidation promoter injected by the oxidation promoter injection unit and the amount of ozone injected by the ozone injection unit so that the dissolved ozone concentration measured by the dissolved ozone measurement unit becomes a predetermined target value;
A water treatment method comprising:

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