Additive amount calculation device, water treatment method, water treatment system, and program

Abstract

To optimize an amount of addition of a catalase to water to be treated when performing decomposition treatment of hydrogen peroxide in the water to be treated by adding the catalase in order to obtain treated water.SOLUTION: An additive amount calculation device 30 is provided which calculates a catalase additive amount or additive concentration. The additive amount calculation device 30 includes: a database 31 which stores data for derivation of an amount of catalase required for decomposition of hydrogen peroxide; an input unit 32 which receives an input of a hydrogen peroxide concentration of water to be treated, a pH of the water to be treated, and a treatment target value (values of both target treatment time of the decomposition of the hydrogen peroxide and a target hydrogen peroxide concentration in treated water); and a calculation unit 33 which searches the database 31 on the basis of the input to the input unit 32 and calculates the catalase additive amount or additive concentration for the decomposition of the hydrogen peroxide.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the control of the amount of catalase to be added when performing water treatment using catalase, and in particular to an addition amount calculation device that calculates the amount or concentration of catalase to be added, a water treatment method and system in which the amount of catalase to be added is controlled, and a program used to calculate the amount or concentration of catalase to be added. [Background technology]

[0002] Hydrogen peroxide (H2O2) is widely used in processes such as cleaning and sterilization, and wastewater containing hydrogen peroxide is discharged from these processes. Since wastewater containing hydrogen peroxide cannot be discharged directly into the environment, it is necessary to carry out water treatment to decompose and remove the hydrogen peroxide in the wastewater. Patent Document 1 discloses a water treatment method for decomposing and removing hydrogen peroxide in the water to be treated, which is the cleaning wastewater, by mixing catalase, which is a hydrogen peroxide decomposing enzyme, with the water to be treated. Catalase is an enzyme derived from living organisms, and is industrially produced by culturing microorganisms such as those of the genus Aspergillus, Thermomyces, or Micrococcus. In the presence of catalase, the hydrogen peroxide in the water to be treated is converted into 2H2O2 → 2H2O + O2 As shown above, hydrogen peroxide is decomposed into water (H2O) and oxygen (O2). Catalase functions as a catalyst to promote the decomposition reaction of hydrogen peroxide. Patent documents 2 and 3 disclose that when hydrogen peroxide in water to be treated is decomposed and removed by adding catalase, a reaction rate calculation is performed based on the hydrogen peroxide concentration in the water to be treated, the residence time of the water to be treated, and the reaction rate constant of the decomposition reaction of hydrogen peroxide in the presence of catalase, and the amount of catalase to be added to the water to be treated is optimized. Patent document 4 discloses a method for calculating the enzyme activity of catalase. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-11689 [Patent Document 2] JP 2020-37062 A [Patent Document 3] JP 2020-37063 A [Patent Document 4] JP 2009-269002 A Summary of the Invention [Problem to be solved by the invention]

[0004] The decomposition reaction of hydrogen peroxide by catalase is also affected by the pH of the water to be treated. It is known that catalase has different properties, including enzyme activity, depending on which biological species produced the catalase, and when using catalase of a different species, it may be necessary to consider differences in enzyme activity due to differences in species produced. Therefore, the method described in Patent Documents 2 and 3, which determines the amount of catalase to be added to the water to be treated by reaction rate calculation using the hydrogen peroxide concentration in the water to be treated, the residence time, and a uniquely determined reaction rate constant, is unable to determine the optimal amount of catalase to be added, and may result in insufficient or excessive catalase being added.

[0005] The object of the present invention is to provide an addition amount calculation device that can calculate the optimal amount of catalase to be added when performing water treatment by adding catalase to the water to be treated, a water treatment method and water treatment system that can optimize the amount of catalase to be added to the water to be treated, and a program used to calculate the optimal amount of catalase to be added. [Means for solving the problem]

[0006] One embodiment of the addition amount calculation device of the present invention is an addition amount calculation device that calculates the amount of catalase to be added when catalase is added to water to be treated that contains hydrogen peroxide to decompose the hydrogen peroxide and obtain treated water, and has a database that stores data for deriving the amount of catalase required to decompose the hydrogen peroxide contained in the water to be treated, an input unit that accepts at least an input indicating the hydrogen peroxide concentration of the water to be treated, an input indicating the pH of the water to be treated, an input related to a target treatment time for the decomposition of hydrogen peroxide, and an input related to a target hydrogen peroxide concentration in the treated water, and a calculation unit that searches the database based on the input accepted by the input unit and calculates the amount or concentration of catalase to be added to decompose the hydrogen peroxide in the water to be treated.

[0007] One embodiment of the water treatment method of the present invention is a water treatment method in which catalase is added to water to be treated that contains hydrogen peroxide, thereby decomposing the hydrogen peroxide and obtaining treated water, and includes an input step of receiving at least an input indicating the hydrogen peroxide concentration in the water to be treated, an input indicating the pH of the water to be treated, an input related to a target treatment time for the decomposition of hydrogen peroxide, and an input related to a target hydrogen peroxide concentration in the water to be treated, and a calculation step of searching a database storing data for deriving the amount of catalase required to decompose the hydrogen peroxide contained in the water to be treated based on the input received in the input step, and calculating the amount or concentration of catalase to be added for decomposing the hydrogen peroxide in the water to be treated.

[0008] One embodiment of the water treatment system of the present invention is a water treatment system that adds catalase to water to be treated that contains hydrogen peroxide to decompose the hydrogen peroxide and obtain treated water, and has one embodiment of an addition amount calculation device, a storage tank for storing a catalase solution, and an addition means connected to the storage tank and adding the catalase solution to the water to be treated based on a first signal output from the addition amount calculation device.

[0009] A program of one embodiment of the present invention causes a computer to execute an input process that receives at least an input indicating the hydrogen peroxide concentration of the water to be treated, an input indicating the pH of the water to be treated, an input related to a target treatment time for the decomposition of hydrogen peroxide, and an input related to a target hydrogen peroxide concentration in the treated water obtained by decomposing the hydrogen peroxide in the water to be treated, and a process of searching a database that stores data for deriving the amount of catalase required to decompose the hydrogen peroxide contained in the water to be treated based on the input received in the input process, and calculating the amount or concentration of catalase to be added to decompose the hydrogen peroxide in the water to be treated. Effect of the Invention

[0010] According to the present invention, when catalase is added to decompose hydrogen peroxide in water to be treated, the amount of catalase added to the water to be treated can be optimized. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a configuration of an addition amount calculation device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a database configuration. [Diagram 3] 1 is a flow chart showing a water treatment system equipped with an addition amount calculation device. [Figure 4] 4 is a flowchart showing the operation of the water treatment system shown in FIG. [Diagram 5] 1 is a flow chart showing another example of a water treatment system. [Figure 6] 1 is a flow chart showing another example of a water treatment system. [Figure 7] 1 is a flow chart showing another example of a water treatment system. [Figure 8] FIG. 11 is a block diagram showing the configuration of an addition amount calculation device according to a second embodiment. [Figure 9] 1 is a flow chart showing a water treatment system equipped with an addition amount calculation device. [Figure 10] 10 is a flowchart showing the operation of the water treatment system shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present invention will be described with reference to the drawings.

[0013] [First embodiment] FIG. 1 shows an addition amount calculation device 30 according to a first embodiment of the present invention. The addition amount calculation device 30 calculates an optimal addition amount or addition concentration of catalase when adding catalase to water to be treated that contains hydrogen peroxide to decompose and remove hydrogen peroxide in the water to be treated, thereby obtaining treated water from which hydrogen peroxide has been removed. The addition amount calculation device 30 includes a database 31 that stores data for deriving the amount of catalase required to decompose hydrogen peroxide contained in the water to be treated, an input unit 32 that receives at least the hydrogen peroxide concentration of the water to be treated, the pH of the water to be treated, and a treatment target value, and a calculation unit 33 that searches the database 31 based on an input to the input unit 32 and calculates the addition amount or addition concentration of catalase for decomposing hydrogen peroxide in the water to be treated. Here, the treatment target value uses both a target treatment time, which indicates how long it takes to perform the treatment to decompose hydrogen peroxide in the water to be treated, and a target hydrogen peroxide concentration, which indicates the hydrogen peroxide concentration in the treated water obtained by the decomposition treatment. There are two types of processing methods for decomposing hydrogen peroxide by adding catalase: batch processing and continuous processing. In the case of batch processing, the processing time is the reaction time in a batch reactor, and in the case of continuous processing, it is the residence time obtained by dividing the volume of the part involved in the reaction by the flow rate. Continuous processing includes the use of one or more reactors where stirring is performed to achieve as uniform a mixed state as possible, and line injection, in which a catalase solution is continuously injected at a constant flow rate into the water to be treated flowing at a constant speed through a pipeline.

[0014] As an example, the database 31 stores data relating the hydrogen peroxide concentration in the water to be treated, the pH of the water to be treated, the concentration of catalase added, the treatment time for the decomposition of hydrogen peroxide, and the hydrogen peroxide concentration in the treated water for each type of catalase used for decomposing hydrogen peroxide and for each treatment method for decomposing hydrogen peroxide. The type of catalase refers to, for example, the species of the microorganism that produced the catalase. FIG. 2 shows an example of the configuration of such a database 31. FIG. 2 shows the configuration of the database 31 provided for a specific type of catalase. In the database 31, for each treatment method, whether batch treatment or continuous treatment, the following four parameters are used as parameters: (1) hydrogen peroxide (H2O2) concentration in the water to be treated, (2) pH of the water to be treated, (3) concentration of catalase added, and (4) treatment time for the decomposition treatment of hydrogen peroxide, i.e., reaction (retention) time. The hydrogen peroxide concentration in the treated water obtained when the decomposition treatment of hydrogen peroxide is performed by combining these four parameters is stored in association with these four parameters. At extremely low or high pH, ​​the decomposition reaction of hydrogen peroxide by catalase does not proceed easily, so in the data stored in database 31, the pH range of the water to be treated is, for example, 2 or more and 12 or less. Since it is possible to calculate the catalase addition concentration required for continuous treatment from the catalase addition concentration in batch treatment, it is necessary to store data for batch treatment in database 31, but it is not necessary to store data for continuous treatment. Similarly, since it is possible to calculate the catalase addition concentration required for batch treatment from the catalase addition concentration in continuous treatment, when data for continuous treatment is stored in database 31, it is not necessarily necessary to store data for batch treatment.

[0015] In response to the database 31 being configured in this way, in this embodiment, the type of catalase to be used, the hydrogen peroxide concentration of the water to be treated, the pH of the water to be treated, the treatment method, and the treatment target value are input to the input unit 32. As the treatment target value, both the target treatment time (i.e., the target reaction time or the target residence time) and the target hydrogen peroxide concentration are input. Since the target hydrogen peroxide concentration is often determined in advance based on the regulation value of the hydrogen peroxide concentration in wastewater, the target hydrogen peroxide concentration may be a default value, and only the target treatment time may be input to the input unit 32 each time as the treatment target value. However, it is necessary to select whether or not to use the default value as the target hydrogen peroxide concentration, and the default value must be provided to the addition amount calculation device 30 as the initial value. Therefore, in this embodiment, if the initial value or the default value is also input, the input related to the target hydrogen peroxide concentration must also be input to the input unit 32 at some stage. As the hydrogen peroxide concentration of the water to be treated and the pH of the water to be treated, values ​​obtained by measuring the water to be treated in advance may be used. Alternatively, in this embodiment, a sensor may be provided to measure the hydrogen peroxide concentration and pH of the water to be treated, and the measurement value output from the sensor may be input to input unit 32, so that the catalase addition concentration can be calculated at any time in the addition amount calculation device 30 to keep up with the ever-changing hydrogen peroxide concentration and pH.

[0016] In the database 31, seven items of data, including (1) the type of catalase, (2) the treatment method, (3) the hydrogen peroxide concentration in the water to be treated, (4) the pH of the water to be treated, (5) the treatment time, (6) the concentration of catalase to be added, and (7) the hydrogen peroxide concentration in the water to be treated, are stored in association with each other as data necessary for determining the optimal amount of catalase to be added to the water to be treated. By inputting six of the seven items of data and searching the database 31, the value of the remaining item of data can be known. Therefore, the calculation unit 33 searches the database 31 based on the type of catalase, the hydrogen peroxide concentration in the water to be treated, the pH of the water to be treated, the treatment method, and the treatment target values ​​(target treatment time and target hydrogen peroxide concentration) input to the input unit 32, and reads out the concentration of catalase to be added corresponding to the input. There may be cases where data that exactly matches the input is not present in the database 31, and in such a case, the calculation unit 33 performs an interpolation calculation or the like to calculate the concentration of catalase to be added corresponding to the input. In particular, when only data related to batch processing is stored in the database 31, but the processing method input to the input unit 32 is continuous processing, the calculation unit 33 searches the database 31 assuming that the processing method is batch processing, calculates the reaction rate constant of the decomposition reaction of hydrogen peroxide by catalase from the search results, and calculates the catalase addition concentration in the case of continuous processing using the calculated reaction rate constant, the hydrogen peroxide concentration and pH of the water to be treated, and the target processing value. Similarly, when calculating the catalase addition concentration in batch processing when only data related to continuous processing is stored in the database 31, it is sufficient to search the database 31 assuming that the processing method is continuous processing, calculate the reaction rate constant based on the search results, and obtain the catalase addition concentration based on that.

[0017] In this way, according to the addition amount calculation device 30 of the present embodiment, the type of catalase used, the hydrogen peroxide concentration of the water to be treated, the pH of the water to be treated, the treatment method, and the treatment target value are input, and the optimum catalase addition concentration for decomposing hydrogen peroxide in the water to be treated can be calculated. Such an addition amount calculation device 30 can also be realized by using a general computer such as a personal computer or a server and executing a program or software for calculating the optimum catalase addition concentration on the computer. Furthermore, when a spreadsheet application program (hereinafter referred to as a spreadsheet application) is executed on a computer, the functions of the input unit 32 and the calculation unit 33 can be realized using commands and macros on the spreadsheet application, and the database 31 can be stored in a data file for the spreadsheet application, and the commands and macros for realizing the functions of the input unit 32 and the calculation unit 33 can also be stored in the same data file. If such a data file is created, the computer on which the spreadsheet application is installed can function as the addition amount calculation device 30 by opening the data file with the spreadsheet application.

[0018] Furthermore, in the addition amount calculation device 30 of this embodiment, in order to control the concentration of catalase added when hydrogen peroxide in the water to be treated is actually being decomposed and removed, an addition amount control unit 34 may be provided that generates and outputs a control signal for controlling the addition of catalase based on the concentration of catalase calculated by the calculation unit 33, as shown by the dashed line in Fig. 1. The control signal is, for example, a signal for controlling a pump that supplies the catalase solution to the water to be treated.

[0019] The decomposition reaction of hydrogen peroxide by catalase may be affected by the temperature of the water to be treated and the presence of inhibitors contained in the water to be treated. Examples of inhibitors include ammonium ions and fluoride ions. Therefore, when the calculation unit 33 calculates the optimal concentration of catalase to be added, the catalase addition concentration may be corrected according to the water temperature and the type and concentration of inhibitors contained in the water to be treated. In addition, since peracetic acid is an equilibrium mixture of acetic acid, hydrogen peroxide, and water, and decomposing hydrogen peroxide in water to be treated containing peracetic acid results in decomposing peracetic acid, the addition amount calculation device 30 of this embodiment can also be applied to the decomposition of peracetic acid in the water to be treated.

[0020] Fig. 3 shows the configuration of a water treatment system including the above-mentioned addition amount calculation device 30. The water treatment system shown in Fig. 3 adds catalase, which is a hydrogen peroxide decomposition enzyme, to water to be treated that contains hydrogen peroxide, thereby decomposing and removing hydrogen peroxide, thereby obtaining treated water from which hydrogen peroxide has been removed. In Fig. 3, pipes through which liquid flows are shown by solid lines, and paths of electrical signals are shown by dashed lines. The addition amount calculation device 30 is also provided with an addition amount control unit 34.

[0021] A pipe 10 is provided through which water to be treated supplied from the outside flows, and a hydrogen peroxide concentration sensor 11 (indicated as "H2O2 sensor" in the figure) for measuring the hydrogen peroxide concentration in the water to be treated and a pH sensor 12 for measuring the pH of the water to be treated are attached to the pipe 10. The pH of the water to be treated is 2 or more and 12 or less, and the water temperature is 70°C or less. Catalase used to decompose hydrogen peroxide is stored in a storage tank 20 in the form of a solution (i.e., catalase solution) of known concentration or known enzyme activity. The catalase solution may contain additives such as a stabilizer in addition to catalase as a solute and a solvent. In order to inject the catalase solution into the water to be treated, a pipe 21 is provided that extends from the storage tank 20 to the pipe 10 and merges with the pipe 10, and a pump 22 is provided in the pipe 21 to pump out the catalase solution. The pipe 21 and the pump 22 constitute an adding means for adding the catalase solution to the water to be treated. A position A where the pipe 21 joins the pipe 10 is downstream of the positions where the hydrogen peroxide concentration sensor 11 and the pH sensor 12 are provided, in terms of the flow of the water to be treated.

[0022] The hydrogen peroxide concentration measurement value of the water to be treated from the hydrogen peroxide concentration sensor 11 and the pH measurement value of the water to be treated from the pH sensor 12 are input to the addition amount calculation device 30. The type of catalase, the treatment method, and the treatment target value are also input to the addition amount calculation device 30 as external input values. The input unit 32 of the addition amount calculation device 30 accepts these inputs, and based on these inputs, the calculation unit 33 of the addition amount calculation device 30 searches the database 31 to calculate the optimal addition concentration of catalase. Then, the addition amount control unit 34 of the addition amount calculation device 30 outputs a control signal to control the amount of catalase solution discharged by the pump 22, and the operation of the pump 22 is controlled by the control signal. As a result, the pump 22 is controlled to achieve the optimal catalase addition concentration, and the catalase solution is injected from the storage tank 20 via the pipe 21 at the optimal addition concentration, i.e., at an addition concentration that is neither excessive nor insufficient, into the water to be treated flowing through the pipe 10, and treated water from which hydrogen peroxide has been removed is obtained. Although not shown in FIG. 3, a reaction tank for batch or continuous processing may be provided in pipe 10 downstream from position A where the catalase solution is injected from pipe 21.

[0023] FIG. 4 is a flow chart for explaining the operation of the water treatment system shown in FIG. 3. Here, it is assumed that batch treatment is performed. First, in step 101, the type of catalase, the treatment method, the target reaction time, and the target hydrogen peroxide concentration are input to the addition amount calculation device 30 as initial settings, and then in step 102, the measured values ​​of the hydrogen peroxide concentration sensor 11 and the pH sensor 12 at that time are input to the addition amount calculation device 30. Then, in step 103, the calculation unit 33 of the addition amount calculation device 30 searches the database 31 based on these inputs, and in step 104, calculates the optimal catalase addition concentration based on the search results. As a result, a control signal corresponding to the optimal addition concentration is sent from the addition amount calculation device 30 to the pump 22, and in step 105, the pump 22 is controlled to deliver the catalase solution corresponding to the optimal addition concentration.

[0024] 4, the water treatment system is depicted as having the addition amount calculation device 30 built in, but the database 31 and calculation unit 33 of the addition amount calculation device 30 can also be provided in a server connected to the water treatment system via a communication network. In this case, it is also possible to operate in a so-called cloud format in which one database 31 is used in common for multiple water treatment systems.

[0025] FIG. 5 shows another example of a water treatment system equipped with the additive amount calculation device 30 of the first embodiment. In the water treatment system shown in FIG. 5, one reaction tank 41 is provided in the pipe 10 at a position downstream of position A in the flow of the water to be treated in the water treatment system shown in FIG. 3. The reaction tank 41 is, for example, for continuous treatment or batch treatment. FIG. 6 shows yet another example of a water treatment system. In the water treatment system shown in FIG. 6, a further reaction tank 42 is provided downstream of the reaction tank 41 in the flow of the water to be treated in the water treatment system shown in FIG. 5. This reaction tank 42 is, for example, for continuous treatment.

[0026] The addition amount calculation device 30 can be configured to determine the optimal addition concentration of catalase and to adjust at least one of the pH and the residence time of the water to be treated. FIG. 7 shows the configuration of a water treatment system equipped with such an addition amount calculation device 30. The water treatment system shown in FIG. 7 is the water treatment system shown in FIG. 5, further provided with a storage tank 25 for storing a liquid pH adjuster, a pipe 26 extending from the storage tank 25 to the pipe 10 and joining the pipe 10, and a pump 27 for sending out the pH adjuster. The pump 27 is provided in the pipe 26. The pipe 26 and the pump 27 are provided to add the pH adjuster to the water to be treated. The position B where the pipe 26 joins the pipe 10 is downstream of the positions where the hydrogen peroxide concentration sensor 11 and the pH sensor 12 are provided, with respect to the flow of the water to be treated, and upstream of the position A where the catalase solution is injected. Furthermore, in piping 10, pump 13 for adjusting retention time is provided downstream of the positions where hydrogen peroxide concentration sensor 11 and pH sensor 12 are provided and upstream of position B in relation to the flow of the water to be treated so that the amount of water to be treated can be adjusted. Pumps 13, 27 are also controlled by a control signal output from addition amount calculation device 30. Pipe 10 may be provided with a flow meter (not shown) for actually measuring the flow rate at pump 13. Note that the position at which flow rate adjustment for adjusting retention time is performed is not limited to a position downstream of the positions where hydrogen peroxide concentration sensor 11 and pH sensor 12 are provided and upstream of position B.

[0027] In the water treatment system shown in FIG. 7, the addition amount calculation device 30 refers to the database 31 to determine the catalase addition concentration, and adjusts at least one of the pH and the residence time of the water to be treated to optimize the decomposition reaction of hydrogen peroxide based on the result. When adjusting the pH of the water to be treated, the addition amount calculation device 30 determines the amount of pH adjuster to be added to the water to be treated, and controls the pump 27 so that the amount of pH adjuster is added to the water to be treated. The addition amount calculation device 30 controls the pump 27, so that the previously determined amount of pH adjuster is added to the water to be treated to adjust the pH of the water to be treated. When adjusting the residence time, the addition amount calculation device 30 controls the pump 13. If the reaction tank 41 is for continuous treatment, the residence time in the reaction tank 41 will be longer if the flow rate of the water to be treated sent out by the pump 13 is reduced, so the residence time can be changed by controlling the pump 13. Of course, the method of changing the residence time is not limited to the method of changing the flow rate of the water to be treated sent out by the pump 13, and various known methods can be used. For example, in the case of batch treatment, a method of changing the timing of discharging treated water from the reaction tank can be used. In the water treatment system shown in Fig. 7, not only the catalase addition concentration but also at least one of the pH and residence time of the water to be treated is adjusted, so that further optimization of the catalase addition concentration can be realized.

[0028] [Second embodiment] In the addition amount calculation device 30 of the first embodiment, data for obtaining an optimal catalase addition concentration is stored in advance in the database 31. However, the database 31 can also be constructed by machine learning while performing the decomposition process of hydrogen peroxide. In the second embodiment described below, an addition amount calculation device in which the database 31 is constructed by machine learning will be described. Figure 8 shows an addition amount calculation device 35 of the second embodiment.

[0029] The second embodiment of the addition amount calculation device 35 shown in FIG. 8 is obtained by adding a machine learning unit 36 ​​that performs machine learning of the database 31 by receiving the hydrogen peroxide concentration of the treated water from the addition amount calculation device 30 shown in FIG. 1. The hydrogen peroxide concentration of the water to be treated, the pH of the water to be treated, and the target reaction time are input to the machine learning unit 36 ​​from the input unit 32, and the data of the catalase addition concentration calculated in the calculation unit 33 is also input. The machine learning unit 36 ​​performs machine learning based on these input data and updates the data stored in the database 31. The actual reaction time may be input to the machine learning unit 36 ​​instead of the target reaction time. In the addition amount calculation device 35 of the second embodiment, the data stored in the database 31 is updated from time to time by machine learning, so that the catalase addition concentration is further optimized as the decomposition process of hydrogen peroxide continues. When the database 31 and the calculation unit 33 are provided in the cloud, it is preferable that the machine learning unit 36 ​​is also provided in the cloud.

[0030] Fig. 9 shows an example of the configuration of a water treatment system including the addition amount calculation device 35 shown in Fig. 8. This water treatment system is the water treatment device shown in Fig. 5, in which the addition amount calculation device 30 of the first embodiment is replaced with the addition amount calculation device 35 of the second embodiment, and a hydrogen peroxide concentration sensor 14 is provided to measure the hydrogen peroxide concentration of outlet water from reaction tank 41, i.e., the treated water. The hydrogen peroxide concentration of the treated water measured by the hydrogen peroxide concentration sensor 14 is directly input to the machine learning unit 36 ​​in the addition amount calculation device 35.

[0031] Fig. 10 is a flowchart showing the operation of the water treatment system shown in Fig. 9. The processing from step 101 to step 105 proceeds in the same manner as in Fig. 4. After step 105 is completed, the hydrogen peroxide concentration of the treatment water is measured by hydrogen peroxide concentration sensor 14 in step 106, and then machine learning unit 36 ​​performs machine learning of database 31 in step 107.

[0032] Next, it will be explained that in each of the above-mentioned embodiments, the catalase concentration to be added in a continuous process can be determined based on data from a batch process.

[0033] Since the decomposition reaction of hydrogen peroxide by catalase is known to be a first-order reaction, the following formula is established if the initial hydrogen peroxide concentration is C0, the final hydrogen peroxide concentration is C1, the treatment time is t, and the reaction rate constant is k. With regard to continuous treatment, one tank refers to the case where hydrogen peroxide decomposition treatment is performed by continuous treatment using one reaction tank 41 as shown in FIG. 5, and two tanks refers to the case where hydrogen peroxide decomposition treatment is performed by continuous treatment using two reaction tanks 41 and 42 arranged in series as shown in FIG. 6. Note that even when one reaction tank is divided into two by a partition plate or the like, it can be considered that two reaction tanks are provided. Similar considerations can be made when the number of reaction tanks in continuous treatment is further increased.

[0034]

number

[0035] Since the reaction rate constant changes depending on the concentration of catalase added, the above formula can be transformed into the following formula by substituting the reaction rate constant with the catalase concentration as a variable for k, where x is the concentration of the catalase solution added.

[0036]

number

[0037] Here, a and b are both constants specific to the input conditions (type of catalase, initial hydrogen peroxide concentration, and pH). In other words, if a and b are known, the treatment method, treatment time, and hydrogen peroxide concentration of the treatment water can be set arbitrarily, and the amount of catalase required to be added can be calculated. Since a and b can be determined by, for example, least squares fitting using data from batch processing, the optimal catalase addition concentration for continuous processing can be determined by searching database 31, which stores only data from batch processing. EXAMPLES

[0038] The present invention will be described in more detail below by explaining the results of experiments carried out by the inventors. In the experiments, unless otherwise specified, a water treatment system shown in FIG. 5 having one reaction tank 41 was assembled and used. The water to be treated was the city water of Sagamihara City that had been treated with activated carbon, and an aqueous hydrogen peroxide solution (special grade, manufactured by Kanto Chemical) was added to the water so that the hydrogen peroxide content was at a specified value. Two types of catalase solutions were used: a catalase solution in which the producing bacterium belongs to the genus Thermomyces and has an enzyme activity of about 50,000 u / g, and a catalase solution in which the producing bacterium belongs to the genus Aspergillus and has an enzyme activity of about 50,000 u / g. The unit of enzyme activity, "u (unit)", is the performance of decomposing 1 μmol of hydrogen peroxide per minute at 30° C., and was specifically determined by the method disclosed in Patent Document 4. In each table showing the results, "-" indicates that there is no measurement result or that it is not possible to measure.

[0039] [Experiment 1] The pH dependency of the hydrogen peroxide decomposition rate in the decomposition reaction of hydrogen peroxide by catalase was investigated. Water to be treated with various pH values ​​was used, and the hydrogen peroxide concentration of the water to be treated was set to 1000 mg / L, and a catalase solution was added to the water to be treated so that the catalase solution concentration was 100 mg / L. The decomposition treatment of hydrogen peroxide was carried out in batches with a residence time of 30 minutes. The hydrogen peroxide concentration of the outlet water of the reaction tank 41, i.e., the residual hydrogen peroxide concentration, was measured to determine the hydrogen peroxide decomposition rate. The results are shown in Table 1. As is clear from Table 1, it was found that the pH of the water to be treated is preferably 2 or more and 12 or less. When the catalase-producing bacteria is the genus Thermomyces, the pH of the water to be treated is preferably 3 or more and 11 or less.

[0040] [Table 1]

[0041] [Experiment 2] The effect of water temperature on the decomposition reaction of hydrogen peroxide by catalase was investigated. A catalase solution produced by Aspergillus bacteria was added to water to be treated, which had a pH of 7 and a hydrogen peroxide concentration of 1000 mg / L, so that the concentration was 50 mg / L. The decomposition reaction of hydrogen peroxide was allowed to proceed at various temperatures, and the elapsed time and the residual hydrogen peroxide concentration were measured to investigate the dependency of the decomposition reaction on water temperature. The results are shown in Table 2. It was found from Table 2 that the treatment performance of hydrogen peroxide deteriorates when the water temperature exceeds 70°C. Therefore, it is preferable that the temperature of the water to be treated is 70°C or lower.

[0042] [Table 2]

[0043] [Experiment 3] The relationship between the elapsed time of the decomposition treatment and the residual hydrogen peroxide concentration under various conditions was investigated. The decomposition treatment of hydrogen peroxide was carried out in batches by changing the pH, hydrogen peroxide concentration, type of catalase (producing bacteria), and catalase solution concentration in the water to be treated, and the hydrogen peroxide concentration in the outlet water of the reaction tank 41, i.e., the residual hydrogen peroxide concentration, was determined. The results when the hydrogen peroxide concentration in the water to be treated was 100 mg / L are shown in Table 3, the results when it was 500 mg / L are shown in Table 4, and the results when it was 1000 mg / L are shown in Table 5. It was found from Tables 3 to 5 that the decomposition treatment performance of hydrogen peroxide differs depending on the pH of the water to be treated, and also differs depending on the bacteria that produce catalase.

[0044] [Table 3]

[0045] [Table 4]

[0046] [Table 5]

[0047] [Experiment 4] The difference in hydrogen peroxide decomposition performance due to the difference in treatment method, i.e., batch treatment or continuous treatment, was investigated. For continuous treatment, the case of one reaction tank and the case of two reaction tanks were investigated. When the reaction tank was two tanks, the water treatment system shown in FIG. 6 was used. A catalase solution containing Thermomyces as the producing bacteria was used, the hydrogen peroxide concentration in the treated water was set to 1000 mg / L, and the retention time was set to 30 minutes (when the reaction tank was two tanks, the retention time in each tank was set to 15 minutes), and the hydrogen peroxide decomposition treatment was performed and the residual hydrogen peroxide concentration was measured. The pH and catalase solution concentration in the treated water are as shown in Table 6. When two reaction tanks were provided, the hydrogen peroxide concentration in the outlet water of the downstream reaction tank 42 was taken as the residual hydrogen peroxide concentration. The results are shown in Table 6. From Table 6, it can be seen that the required catalase concentration differs depending on the processing method, that a higher catalase concentration is required for continuous processing compared to batch processing, and that in continuous processing, the required catalase concentration is smaller when there are two reaction tanks than when there is one.

[0048] [Table 6] [Explanation of symbols]

[0049] 10,21,26 Piping 11,14 Hydrogen peroxide concentration sensor 12 pH Sensor 13,22,27 Pump 20,25 storage tank 30,35 Addition amount calculation section 31 Database 32 Input section 33 Calculation section 34 Addition amount control section 36 Machine Learning Department 41,42 Reactor

Claims

1. An apparatus for calculating an amount of catalase to be added to water to be treated that contains hydrogen peroxide to decompose the hydrogen peroxide and obtain treated water, comprising: A database storing data for deriving the amount of catalase required to decompose hydrogen peroxide contained in the water to be treated; an input unit that receives at least an input indicating a hydrogen peroxide concentration in the water to be treated, an input indicating a pH of the water to be treated, an input regarding a target treatment time for decomposing hydrogen peroxide, and an input regarding a target hydrogen peroxide concentration in the water to be treated; A calculation unit that searches the database based on the input received by the input unit and calculates an amount or concentration of catalase to be added for decomposing hydrogen peroxide in the water to be treated; An addition amount calculation device having the above structure.

2. The database stores data relating the hydrogen peroxide concentration in the water to be treated, the pH of the water to be treated, the treatment time for decomposing hydrogen peroxide, the concentration of catalase added, and the hydrogen peroxide concentration in the water to be treated, for each type of catalase and for each treatment method for decomposing hydrogen peroxide in the water to be treated, The processing method includes at least one of batch processing and continuous processing, 2. The addition amount calculation device according to claim 1, wherein the input received by the input unit includes an input for specifying a type of catalase to be used and an input for specifying a processing method to be performed.

3. 3. The addition amount calculation device according to claim 1 or 2, further comprising an addition amount control unit that generates and outputs a first signal for controlling the addition of catalase based on the addition amount or the addition concentration calculated by the calculation unit.

4. A water treatment method comprising adding catalase to water to be treated that contains hydrogen peroxide to decompose the hydrogen peroxide and obtain treated water, an input process for receiving at least an input indicating a hydrogen peroxide concentration in the water to be treated, an input indicating a pH of the water to be treated, an input regarding a target treatment time for decomposing hydrogen peroxide, and an input regarding a target hydrogen peroxide concentration in the water to be treated; a calculation step of searching a database storing data for deriving an amount of catalase required to decompose hydrogen peroxide contained in the water to be treated based on the input received in the input step, and calculating an amount or concentration of catalase to be added for decomposing hydrogen peroxide in the water to be treated; The water treatment method comprises:

5. The database stores data relating to the hydrogen peroxide concentration in the water to be treated, the pH of the water to be treated, the treatment time for decomposing hydrogen peroxide, the concentration of catalase added, and the hydrogen peroxide concentration in the water to be treated, for each type of catalase and for each treatment method for decomposing hydrogen peroxide in the water to be treated, The processing method includes at least one of batch processing and continuous processing, The water treatment method according to claim 4 , wherein the input received in the input step includes an input designating a type of catalase to be used and an input designating a treatment method to be performed.

6. The water treatment method according to claim 4 or 5, further comprising a reaction step of adding catalase to the treated water based on the addition amount or the addition concentration calculated in the calculation step to decompose hydrogen peroxide in the treated water and remove hydrogen peroxide from the treated water.

7. The water treatment method according to claim 6 , further comprising determining the treatment time for optimizing the decomposition of hydrogen peroxide in the calculation step, and adjusting an actual treatment time for the decomposition of hydrogen peroxide to the determined treatment time.

8. The water treatment method according to claim 6 , further comprising determining a pH of the water to be treated that optimizes decomposition of hydrogen peroxide in the calculation step, and adjusting the pH of the water to be treated to the determined pH.

9. A water treatment system in which catalase is added to water to be treated that contains hydrogen peroxide to decompose the hydrogen peroxide and obtain treated water, The additive amount calculation device according to claim 3, a storage tank for storing a catalase solution; an addition means connected to the storage tank and adding the catalase solution to the water to be treated based on the first signal output from the addition amount calculation device; A water treatment system comprising:

10. A first measuring means for measuring a hydrogen peroxide concentration in the water to be treated; A second measuring means for measuring the pH of the water to be treated; Equipped with The water treatment system according to claim 9 , wherein the measurement value of the first measurement means and the measurement value of the second measurement means are supplied to the addition amount calculation device as the first input and the second input, respectively.

11. On the computer, an input process for receiving at least an input indicating a hydrogen peroxide concentration in the water to be treated, an input indicating a pH of the water to be treated, an input relating to a target treatment time for decomposing hydrogen peroxide, and an input relating to a target hydrogen peroxide concentration in the treated water obtained by decomposing the hydrogen peroxide in the water to be treated; A process of searching a database storing data for deriving the amount of catalase required to decompose hydrogen peroxide contained in the water to be treated based on the input received in the input process, and calculating the amount or concentration of catalase to be added for decomposing hydrogen peroxide in the water to be treated; A program that executes the following.

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