System and method for electrolyzing water to be treated

Abstract

The object of the present invention is to provide a system and method for electrolyzing water to be treated so as to contain a predetermined concentration of free residual halogens while suppressing the generation of by-products. [Solution] The above objective can be achieved by an electrolysis system for water to be treated, comprising an electrolysis tank, a residual chlorine response means, and a control means, wherein the control means performs electrolysis to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before electrolysis, and controls the system to terminate the electrolysis based on the value of the electrochemical change in the water to be treated measured by the residual chlorine response means.

Description

【Technical Field】 【0001】 The present invention relates to a system and method used for electrolyzing treated water. 【Background Art】 【0002】 In the process of subjecting treated water such as wastewater to water treatment and regenerating it into purified water, a sterilization treatment for killing pathogens such as bacteria, viruses, and protozoa is performed. For example, by using an oxidizing agent, the cell membrane of the pathogen can be destroyed and the pathogen can be killed. 【0003】 As a sterilization method using an oxidizing agent, in addition to the addition method of adding an oxidizing agent to the treated water, an electrolysis method is available in which the treated water is subjected to electrolysis treatment using halides, halide ions, etc. contained in the treated water, and the treated water is sterilized by the oxidizing agent generated. For example, when chloride is present in the treated water, hypochlorous acid (HClO) is generated from chloride ions according to the following reaction formula. 2Cl - →Cl2+2e - Cl2+H2O→HClO+H + +Cl - 【0004】 Hypochlorous acid generated by electrolysis is a powerful oxidizing agent and can kill pathogens. As a method for generating hypochlorous acid by electrolysis, for example, a method for generating sterilized water is known in which the electrical conductivity of tap water is measured and a current for generating hypochlorous acid at a target concentration is applied between electrodes based on this electrical conductivity (see, for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 Japanese Patent Laid-Open No. 10-328667 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0006】 However, with electrolysis, the amount of chloride present in the treated water is unknown, and it is difficult to control the applied voltage and energizing time to obtain the desired pathogen killing efficiency (pathogen killing rate, pathogen removal rate). In addition, electrolysis of treated water can produce by-products, and it is not desirable to carry it out for a long time. Furthermore, multiple types of chloride may be present in the treated water, making it difficult to accurately determine the chloride concentration in the treated water. 【0007】 For example, when water containing chloride is subjected to electrolysis, the total residual chlorine generated includes chlorine gas (Cl2), hypochlorous acid (HOCl), and hypochlorite ions (OCl). - In addition to free residual chlorine, the treated water contains combined residual chlorine such as monochloramine (NH2Cl), dichloramine (NHCl2), and trichloramine (NCl3). Furthermore, the bactericidal effect of combined residual chlorine is much weaker than that of free residual chlorine. Therefore, it is desirable that the electrolyzed water obtained by subjecting the water to be treated to electrolysis contains a certain concentration of free residual chlorine. However, the method described in Patent Document 1 does not allow for the determination of the concentration of free residual chlorine in the electrolyzed water. 【0008】 Therefore, the problem that the present invention aims to solve is to provide a system and method for electrolyzing water to be treated so that it contains a predetermined concentration of free residual halogens while suppressing the generation of by-products. [Means for solving the problem] 【0009】 To solve the above problems, the inventors diligently conducted research on estimating the concentration of free residual chloride in the treated water and estimating the endpoint of the electrolysis treatment. In this research, when the chlorine concentration of the treated water was measured with a residual chlorine meter, the total residual chlorine could be measured, but the concentration of free residual chlorine could not be accurately determined.Therefore, after further investigation, the inventors found that there is a correlation between the integral value of the electrochemical change value shown by the residual chlorine meter over a predetermined time and the free chlorine concentration in the treated water, and that the endpoint of sterilization of the treated water can be estimated when the integral value of the electrochemical change value reaches a predetermined value. 【0010】 After further trial and error, the inventors considered that by setting an integral value of the values ​​over a predetermined time based on the electrochemical changes in the water being treated during electrolysis, and setting the electrolysis process to end when the integral value reaches a predetermined value, it might be possible to efficiently sterilize the water being treated while avoiding excessive electrolysis. 【0011】 Based on these ideas, the inventors finally succeeded in creating a system and method for electrolyzing water to be treated in a way that suppresses the generation of by-products while containing a predetermined concentration of free residual halogens, thereby solving the problems of the present invention. The present invention is completed based on these initial ideas and successful examples made by the inventors. 【0012】 In other words, according to each aspect of the present invention, the following embodiments are provided. [1] An electrolysis system for water to be treated, The system comprises an electrolysis cell, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the electrochemical changes in the treated water contained in the electrolysis tank, and The control means controls the electrolysis treatment to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before the electrolysis treatment, and to terminate the electrolysis treatment based on the electrochemical changes in the water to be treated measured by the residual chlorine response means. The aforementioned system. [2] A method for electrolyzing water to be treated, A step of performing electrolysis to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before electrolysis treatment, A step of measuring the electrochemical changes of the water to be treated during the electrolysis treatment, A step of terminating the electrolysis treatment based on the measured electrochemical changes in the water to be treated. The method, including the method described above. [3] A sterilization treatment system for water to be treated, The system comprises an electrolysis cell, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the electrochemical changes in the treated water contained in the electrolysis tank, and The control means controls the electrolysis treatment to generate halogenated oxygen acids from halides and / or halide ions in the water to be treated before the electrolysis treatment, to sterilize microorganisms in the water to be treated with the generated halogenated oxygen acids, and to terminate the electrolysis treatment based on the electrochemical changes in the water to be treated measured by the residual chlorine response means. The aforementioned system. [4] A method for sterilizing water to be treated, A step of generating halogenated oxygen acids from halides and / or halide ions in the water to be treated before electrolysis treatment, and performing electrolysis treatment to sterilize microorganisms in the water to be treated with the generated halogenated oxygen acids, A step of measuring the electrochemical changes of the water to be treated during the electrolysis treatment, A step of ending the electrolysis treatment based on the value of the measured electrochemical change of the water to be treated The method including the above. [5] The system according to item [1] or [3], wherein the value is an integrated value. [6] The method according to item [2] or [4], wherein the value is an integrated value. [Effect of the Invention] 【0013】 According to the present invention, while suppressing the generation of by-products, the water to be treated can be electrolyzed so as to contain free residual halogen at a predetermined concentration, thereby killing pathogens in the water to be treated. Further, according to the present invention, the free residual halogen concentration can be accurately grasped, and since it is direct and accurate for obtaining the CT value (Concentration-Time Value; Disinfectant (mg / L) × Contact Time (minutes)), from the measured free residual halogen concentration, the contact time for achieving the desired Log removal rate can be calculated (corrected at appropriate pH and temperature), and the end of the electrolysis treatment, that is, the end of sterilization can be determined. 【0014】 In the sterilization of water to be treated containing various organic substances, since the free residual halogen by electrolysis is consumed for the decomposition of organic substances immediately after the start, the point where the value of the electrochemical change by the residual chlorine meter starts to rise is detected as the start point of the generation of free residual halogen, and the end time of the electrolysis treatment can be determined with the integrated value of the value of the electrochemical change. It is not necessary to directly monitor the concentration of free residual halogen after the start point of the generation of free residual halogen, and it becomes possible to monitor the sterilization process of the water to be treated in real time by monitoring the value of the electrochemical change output by the residual chlorine meter. [Brief Description of the Drawings] 【0015】 [Figure 1] FIG. 1 is a layout diagram of an electrolysis system 1 for water to be treated. [Figure 2]Figure 2 shows the relationship over time between the free residual chlorine concentration measured with DPD reagent in the treated water and the electromotive force between electrodes. [Figure 3] Figure 3 is a block diagram showing the functional configuration of the control means 5. [Figure 4] Figure 4 is a flowchart showing the electrolysis treatment method using an electrolysis system for the water to be treated. [Figure 5] Figure 5 is a layout diagram of the electrolysis system 10 for the water to be treated. [Figure 6] Figure 6 is a layout diagram of the wastewater treatment system 100 incorporating the electrolysis system 1 for the water to be treated. [Modes for carrying out the invention] 【0016】 The details of each aspect of the present invention will be described below, but the present invention can take various forms insofar as it achieves its objective. 【0017】 In this specification, unless otherwise specified, each term is used in the sense commonly used by those skilled in the art, such as in the field of water treatment, and should not be interpreted as having an unreasonably restrictive meaning. Furthermore, since the assumptions and theories made herein are based on the inventors' prior knowledge and experience, the present invention is not limited solely to such assumptions and theories. 【0018】 "Comprise," "contain," and "include" mean that elements other than those explicitly included can be added (synonymous with "at least include"), but they also encompass "consist of" and "essentially consist of." In other words, "comprise" can mean including the explicitly included elements and any one or more of those elements, consisting of the explicitly included elements, or essentially consisting of the explicitly included elements. "Have" is synonymous with "comprise." Elements include limitations such as parts, means, components, processes, conditions, and parameters. "and / or" and its abbreviated form " / " mean any one, any combination of two or more, or all combinations of the listed related items. Throughout this specification, unless the context clearly indicates a singular term, it shall be understood to include plural terms. As used herein, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" encompasses both the meanings of "based solely on" and "based at least on." A "pathogen" is an organism, part thereof, or substance that exhibits or is likely to exhibit pathogenicity to the human body, and examples include microorganisms such as bacteria, fungi, protozoa, and parasites, as well as organic substances such as lipopolysaccharide proteins, viruses, and prions (proteins). "Pathogen elimination" means reducing the number of pathogens and inactivating their pathogenicity, and includes killing and decomposing pathogens, as well as inhibiting their proliferation. Pathogen elimination includes neutralizing pathogens and disinfecting them. "Sterilization of treated water" means treating the water in a way that kills pathogens. 【0019】 One aspect of the present invention is an electrolysis system for water to be treated. An electrolysis system according to one aspect of the present invention comprises an electrolysis tank, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the electrochemical changes of the water to be treated contained in the electrolysis tank. The control means controls the electrolysis treatment to produce halogen oxygen acids from halides / halide ions in the water to be treated before electrolysis treatment. The control means controls the termination of the electrolysis treatment based on the value of the electrochemical change of the water to be treated measured by the residual chlorine response means. 【0020】 Another aspect of the present invention is a method for electrolyzing water to be treated. An electrolysis method according to one aspect of the present invention includes the steps of: performing an electrolysis treatment to generate halogen oxygen acids from halides / halide ions in the water to be treated before subjecting it to electrolysis treatment; measuring the electrochemical changes of the water to be treated during the electrolysis treatment; and terminating the electrolysis treatment based on the measured values ​​of the electrochemical changes of the water to be treated. 【0021】 Another aspect of the present invention is a sterilization treatment system for water to be treated. A sterilization treatment system according to one embodiment of the present invention comprises an electrolysis tank, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the electrochemical changes of the water to be treated contained in the electrolysis tank. The control means controls the electrolysis treatment to generate halogen oxygen acids from halides / halide ions in the water to be treated before electrolysis treatment, and to sterilize microorganisms in the water to be treated with the generated halogen oxygen acids. The control means controls the electrolysis treatment to be terminated based on the value of the electrochemical change of the water to be treated measured by the residual chlorine response means. 【0022】 Another aspect of the present invention is a method for sterilizing water to be treated. A sterilization method according to one aspect of the present invention includes the steps of: generating halogen oxygen acids from halides / halide ions in the water to be treated before electrolysis treatment, and performing electrolysis treatment to sterilize microorganisms in the water to be treated with the generated halogen oxygen acids; measuring the electrochemical changes of the water to be treated during the electrolysis treatment; and terminating the electrolysis treatment based on the measured values ​​of the electrochemical changes of the water to be treated. 【0023】 The following describes various aspects and embodiments of the present invention with reference to the drawings. In each drawing, elements less relevant to the present invention are omitted. In the drawings, solid arrows (→) indicate the direction of water flow, and dotted arrows (- - →) indicate the direction of input and output. 【0024】 Figure 1 is a layout diagram of a water treatment electrolysis system 1, which is an embodiment of a water treatment electrolysis system according to one aspect of the present invention. The water treatment electrolysis system 1 comprises an electrolysis tank 2, a residual chlorine response means 4, and a control means 5. The water treatment water WW is contained in the electrolysis tank 2, subjected to electrolysis treatment, and then discharged from the electrolysis tank 2 as electrolyzed water EW. 【0025】 The electrolysis tank 2 is equipped with a pair of electrodes 6, consisting of an anode and a cathode, and is capable of subjecting the contained water to be treated WW to electrolysis treatment. Based on input signals from the control means 5, the electrodes 6 are energized by a power source such as a DC power supply to electrolyze the water to be treated WW contained in the electrolysis tank 2. 【0026】 When the water to be treated contains halides such as chlorides, halogenated oxygen acids are generated from halogen ions. Halogenated oxygen acids function as oxidizing agents with activity to kill pathogens. Examples of halogenated oxygen acids include hypohalous acid, halogenous acid, hydrohalic acid, and perhalic acid. Specifically, examples include hypochlorous acid, chlorous acid, hypobromous acid, hydrochloric acid, perchloric acid, and monobasic fluorine-containing oxyacids, but hypochlorous acid, which has strong activity to kill pathogens, is preferred. When chloride ions (Cl) are present in the water to be treated WW, - If ) is present, hypochlorous acid (HClO) will be generated by electrolysis of the treated water WW. 【0027】 Electrode 6 can be appropriately configured depending on the type of oxidizing agent to be produced, but it is preferably an electrode that generates halogen oxygen acids from halides in the treated water when current is applied, and more preferably a galvanic electrode. To increase the efficiency of halogen oxygen acid production, electrode 6 is preferably coated with a catalyst such as iridium, ruthenium, platinum, or tantalum, or an alloy thereof, such as titanium. Specific examples of electrode 6 include electrodes coated with iridium and ruthenium on titanium. 【0028】 The residual chlorine response means 4 is capable of measuring the electrochemical changes of the treated water WW contained in the electrolysis tank 2. The measured electrochemical change is expressed as a voltage or current value, for example, in units of V, mV, A, mA, etc. 【0029】 The inventors have measured the electrochemical changes in the treated water and found that there is a certain correlation between the integral value of the electrochemical changes in the treated water over a predetermined time and the free residual chlorine concentration of the treated water. Furthermore, the inventors have found that the endpoint of sterilization of the treated water can be estimated when the integral value of the electrochemical changes in the treated water reaches a predetermined value. 【0030】 For example, as shown in Figure 2, when domestic wastewater is subjected to biological treatment and then passed through a microfiltration (MF) membrane to obtain treated water (volume 5L; conductivity 235μS / cm), and then subjected to electrolysis (current 10A; voltage 9.3V), the free residual chlorine concentration (mg / L), manually measured with DPD reagent according to a standard method, shows a low value for 0 to 4 minutes after the start of electrolysis. This period is also called the decomposition phase. During the decomposition phase, the hypochlorous acid produced by the electrolysis of the treated water is consumed in the decomposition of pathogens in the treated water. Note that Figure 2 shows that electrolysis started 1 minute after data logging. 【0031】 Next, during the first 4 to 10 minutes after the start of electrolysis, the concentration of free residual chlorine increases over time. This period is also called the accumulation phase. During the accumulation phase, the number of pathogens in the treated water decreases, the amount of hypochlorous acid produced exceeds the amount consumed, and hypochlorous acid gradually accumulates in the treated water. 【0032】 On the other hand, as shown in Figure 2, the voltage value output from the galvanic type residual chlorine concentration sensor (residual chlorine meter), that is, the value of the electrochemical change in the treated water, shows a relatively low value during the decomposition phase and increases during the accumulation phase, similar to the free residual chlorine concentration. The residual chlorine meter outputs the electromotive force generated by two electrodes (working electrode and counter electrode). 【0033】 Subsequently, after 10 minutes from the start of electrolysis, the free residual chlorine concentration continues to increase. In contrast, the integral value of the electrochemical change approaches a plateau. As a result, while it is difficult to estimate the end time (endpoint) of the electrolysis process by monitoring the free residual chlorine concentration, monitoring the value of the electrochemical change, especially its integral value, allows for a simple and accurate estimation of the end point of the electrolysis process. Referring to Figure 2, the integral voltage value (approximately 170 mV) after 10 minutes from the start of the electrolysis process can be used as an indicator of the end point. As a result, by controlling the electrolysis process based on the value of the electrochemical change (integral value), it becomes possible to electrolyze the water to be treated to contain a predetermined concentration of free residual halogen while suppressing the generation of by-products. In the following, the value of the electrochemical change includes its integral value. 【0034】 The residual chlorine response means 4 converts the measured value of the electrochemical change into an appropriate signal and inputs it to the control means 5. Preferably, the residual chlorine response means 4 is an electrochemical change sensor that transmits the value of the electrochemical change as an electrical signal to the control means 5. The residual chlorine response means 4 may also be a device having a detection probe such as an electrode. Such a device may be capable of measuring only the electrochemical change, or it may be capable of measuring the electrochemical change together with other physicochemical parameters. An example of the latter device is a residual chlorine meter that can also measure the electrochemical change. 【0035】 Residual chlorine meters are broadly classified into galvanic and polarographic types, both of which measure chlorine concentration based on electrochemical principles. Either a galvanic or polarographic residual chlorine meter can be used. 【0036】 The electrochemical value measured is the electromotive force ([V], [mV]) if the residual chlorine response means 4 is a galvanic type residual chlorine meter, and the current ([A], [mA]) that flows during oxidation-reduction if the residual chlorine response means 4 is a polarographic type residual chlorine meter. The residual chlorine response means 4 can directly measure the values ​​of these electrochemical changes and determine the endpoint of the electrolysis treatment from the integral value. This allows for indirect measurement of the residual chlorine concentration and control of the time and output of the electrolysis treatment. 【0037】 A galvanic residual chlorine meter consists of two different metal electrodes (working electrode and counter electrode), an electrolyte (usually a solution containing chloride ions), and a diaphragm (to separate the electrolyte from the measurement solution). In principle, when chlorine dissolves in the electrolyte, a reduction reaction (electron acceptance by chlorine) occurs at one electrode (e.g., a gold electrode), and an oxidation reaction (electron release by silver) occurs at the other electrode (e.g., a silver / silver chloride electrode). The potential difference (electromotive force) between these two electrodes is proportional to the chlorine concentration, so the chlorine concentration can be determined by measuring this potential difference. 【0038】 A polarographic residual chlorine meter consists of a working electrode (e.g., a precious metal such as platinum or gold), a counter electrode (e.g., a silver / silver chloride electrode), a reference electrode (an electrode that serves as a reference for potential), an electrolyte, and a diaphragm. In principle, a constant voltage is applied to the working electrode, and the current generated when chlorine in the solution is reduced on the electrode is measured. By gradually changing the applied voltage, the chlorine reduction reaction begins at a specific voltage (reduction potential), and a current starts to flow. Since this current value is proportional to the chlorine concentration, the chlorine concentration can be determined by measuring the current value. 【0039】 Galvanic residual chlorine meters do not use an external power supply and measure using two electrodes, making them relatively simpler in configuration and more economical compared to polarographic residual chlorine meters that use an external power supply and three electrodes. However, galvanic residual chlorine meters have a relatively slower response speed and lower selectivity compared to polarographic residual chlorine meters. Therefore, when using a galvanic residual chlorine meter as the residual chlorine response means 4, it is preferable to use the integral value of the electrochemical change. 【0040】 The measurement of the electrochemical changes in the treated water WW by the residual chlorine response means 4 is preferably performed continuously during the electrolysis treatment, but it may also be performed intermittently. 【0041】 The control means 5 functions to set and terminate the conditions for the electrolysis treatment in the electrolysis tank 2. Specifically, the control means 5 sets the conditions for the electrolysis treatment to generate halogen oxygen acids from halides / halide ions in the water to be treated WW before electrolysis treatment, and controls the electrolysis treatment to terminate the electrolysis treatment based on the value of the electrochemical change of the water to be treated WW during the electrolysis treatment, as measured by the residual chlorine response means 4. If the value of the electrochemical change is an integral value, the residual chlorine response means 4 may input the value of the electrochemical change as an integral value to the control means 5, or the control means 5 may convert the value input from the residual chlorine response means 4 into an integral value. The control means 5 may control the water to be treated inlet valve 7a, which restricts the inflow of water to be treated WW by opening and closing, and may control the electrolyzed water outlet valve 7b, which restricts the outflow of electrolyzed water EW by opening and closing, in order to subject the water to be treated WW to electrolysis treatment for a predetermined time. 【0042】 Electrolysis is performed by setting conditions such as the voltage applied to electrode 6, the current flowing through electrode 6, and the duration of current application to electrode 6. As shown in Fig. 2(a) of Xiao Huang et al.'s paper (Water Research, Volume 92, 1 April 2016, Pages 164-172), the amount of oxidizing agent produced tends to increase as the voltage applied to electrode 6 increases and the current application time increases. Therefore, it is preferable to set the conditions for electrolysis by estimating the amount of halogenated oxygen acid obtained by subjecting the water to be treated WW to electrolysis. 【0043】 The conditions for electrolysis treatment may be determined by estimating the halogen oxygen acid concentration in the treated water WW based on the value of the electrochemical change of the treated water WW during electrolysis treatment. For example, if the value of the electrochemical change of the treated water WW during electrolysis treatment is small, and it is estimated that the concentration of halogen oxygen acid produced will be small and the decomposition period may be prolonged, the conditions for electrolysis treatment may be set by increasing the voltage applied to electrode 6 and / or increasing the current value flowing through electrode 6. Conversely, if the value of the electrochemical change of the treated water WW during electrolysis treatment is large, and it is estimated that the halogen oxygen acid concentration will be excessively high, the conditions for electrolysis treatment may be set by decreasing the voltage applied to electrode 6 and / or decreasing the current value flowing through electrode 6. 【0044】 The conditions for electrolysis treatment may be set taking into account the types and numbers of pathogens in the treated water WW. For example, if the number of pathogens in the treated water WW is large, it is preferable to set the electrolysis treatment conditions so that the amount of halogenated oxygen acids produced increases accordingly, and if the number of pathogens in the treated water WW is small, it is preferable to set the electrolysis treatment conditions so that the amount of halogenated oxygen acids produced does not become excessive. As shown in Fig. 3(a) of the literature by Yuan et al., the log reduction rate differs depending on the microbial species, and if most of the pathogens in the treated water WW are bacteria, the electrolysis treatment time can be set to a relatively short time. 【0045】 The electrolysis treatment is terminated based on the value of the electrochemical change of the treated water WW during the electrolysis treatment, as measured by the residual chlorine response means 4. The electrolysis treatment of the treated water WW may be terminated or the degree of electrolysis treatment beyond the termination point may be reduced, with the endpoint being the point at which the value of the electrochemical change of the treated water WW changes from increasing to a plateau, or is expected to change to a plateau. In addition to using the endpoint as an indicator, the termination of the electrolysis treatment may also be indicated by a sufficiently large value of the electrochemical change of the treated water WW, for example, the rate of increase relative to the initial value of the electrochemical change. The termination of the electrolysis treatment may also be indicated by a desired pathogen killing rate. 【0046】 The control means 5 preferably has a processing unit that functions to set and terminate the conditions for the electrolysis process in the electrolysis tank 2. As a specific embodiment of the control means 5 having a processing unit, a block diagram showing the functional configuration of the control means 5 is illustrated in Figure 3. 【0047】 As shown in Figure 3, the control means 5 comprises a processing unit 51, a storage unit 52, and an input / output unit 53. The control means 5 may further include a display unit. The display unit displays the value of the electrochemical change detected by the residual chlorine response means 4, the conditions of the electrolysis treatment, etc. Each component is connected to the others so as to be able to communicate with each other via a bus 54. 【0048】 The processing unit 51 is configured to acquire the signal from the residual chlorine response means 4 as an input value and to issue commands to the electrode 6, the water to be treated inlet valve 7a, and the electrolyzed water outlet valve 7b as output values. Based on the signal from the residual chlorine response means 4, the processing unit 51 sets and terminates the conditions for the electrolysis treatment by comparing the trend of the signal history 522 being measured with the index value 521, or by using the setting program 523 / termination program 524. 【0049】 The memory unit 52 is composed of a storage device and stores the index value 521, signal history 522, setting program 523, correction program 524, calculation program 525, etc. The memory unit 52 may also store the signal from the residual chlorine response means 4 that has just been acquired by the control means 5, the output value which is the setting / termination result from the processing unit 51, etc. The setting program 523 functions to cause the processing unit 51 to set the conditions for the electrolysis process based on pre-entered or past electrolysis process setting values, signal history 522, or a comparison between the signal from the residual chlorine response means 4 and the index value 521. The termination program 524 functions to cause the processing unit 51 to terminate the electrolysis process based on the signal history 522 or based on a comparison between the signal from the residual chlorine response means 4 and the index value 521. 【0050】 The processing unit 51 may use the calculation program 525 stored in the memory unit 52 to calculate the halogen oxygen acid concentration or halogen oxygen acid production rate from the measured electrochemical change values, and may also calculate the electrolysis processing time. In this way, the processing unit 51 may convert the measured electrochemical change values ​​into various values ​​or parameters to control the electrolysis process. 【0051】 The input / output unit 53 is configured to transmit signals from the residual chlorine response means 4 to the processing unit 51, and to transmit commands to control the electrodes 6 (and the power supply connected to them) according to the conditions of the electrolysis process based on the setting / completion results of the processing unit 51. 【0052】 Examples of control means 5 include control circuits, microcontrollers, single-board computers, personal computers (notebook PCs, desktop PCs), tablet terminals, and smartphones. 【0053】 Each device connected to the control means 5 via the input / output unit 53 may be independently connected by wire, or may be connected wirelessly via a router or the like, or without such a device. The control means 5 may control the electrolysis process immediately or with a delay based on the signal from the residual chlorine response means 4. 【0054】 The control of the electrolysis process by the control means 5 may be controlled using AI (Artificial Intelligence) or the like based on the signal from the residual chlorine response means 4. A non-limited specific example of controlling the electrolysis process using a machine learning model with AI is described below. The algorithms used for learning and inference include, but are not limited to, unsupervised learning models such as k-means clustering and lazy learning algorithms such as k-nearest neighbors. 【0055】 Controlling electrolysis processes using machine learning models is divided into a learning phase and an inference phase. In the learning phase, the model is trained. Model training is performed using integrated data as input data, which includes values ​​of electrochemical changes in treated water WW stored in a database in the memory of a PC or other device, halide concentration / halide ion concentration, trends in values ​​of electrochemical changes during electrolysis of treated water WW, current value (current density), treatment time, and pathogen killing rate. The integrated data may also include pre-configured data and standard data that correct or complement the above data. Examples of such data include past electrolysis treatment condition setting data, arbitrary pre-configured data, and past electrolysis treatment result data / completion data. During model training, the parameter values ​​constituting the model are adjusted so that the output training result data is suitable for the input data. The training result data is the data of the training results for the electrolysis treatment conditions. 【0056】 In the inference phase, the trained model, i.e., the updated model, is input with integrated data including input data based on the electrochemical change values ​​of the treated water WW that have just been acquired, and the trained result data. Inference processing is performed to obtain inference result data. The inference result data is the data of the inference results for the electrolysis treatment conditions. The inference processing can be performed using the algorithm described above, etc. 【0057】 By using the electrolysis system 1 for treated water, the electrolysis treatment of the treated water WW can be appropriately performed based on the values ​​of the electrochemical changes, so as to achieve the killing of pathogens and prevent excessive electrolysis that would generate by-products even after the pathogens have been killed. Furthermore, by inputting a desired pathogen killing rate as a set value, it is possible to control the conditions of the electrolysis treatment to be set and terminate so that the pathogen killing rate is achieved. 【0058】 The treated water WW can be any water containing pathogens that can be killed by electrolysis. Examples include domestic wastewater discharged from drainage facilities such as washrooms, toilets, kitchens, bathrooms, and laundry rooms, as well as urban wastewater, commercial wastewater, agricultural wastewater, industrial wastewater, sewage, rainwater, surface water, seawater, tap water, and treated water obtained by chemical treatment, biological treatment, filtration, etc. The treated water WW contains halides / halide ions so that halogen oxygen acids can be generated by electrolysis. If the amount of halides / halide ions in the treated water WW is small, halides (e.g., NaCl) may be added to the treated water WW. Organic compounds can also be decomposed by electrolysis of the treated water WW. 【0059】 Electrolyzed water EW is water obtained by subjecting water to be treated WW to electrolysis treatment, and is water in which the number of pathogens in the water to be treated WW has been reduced, preferably water in which the number of pathogens is 1 / 100 to 1 / 100,000,000 (log2 to log8 reduction) compared to the number in the water to be treated WW. 【0060】 The electrolysis system 1 of the water to be treated may also include other means, including a free residual chlorine measuring means. The residual chlorine concentration value measured by the free residual chlorine measuring means is input to the control means 5 and used together with the value of the electrochemical change measured by the residual chlorine response means 4 to set or terminate the conditions of the electrolysis treatment, or to modify the setting and termination of the conditions of the electrolysis treatment, which is performed based on the value of the electrochemical change. The residual chlorine response means 4 may also function as the free residual chlorine measuring means. 【0061】 An example of the electrolysis treatment method using the electrolysis system 1 for the water to be treated will be explained using the flowchart shown in Figure 4. 【0062】 As illustrated in Figure 4, the control means 5 controls the water to be treated inlet valve 7a to open, and then to close, so that the water to be treated WW flows into the electrolysis tank 2 (S101). Next, the water to be treated WW is subjected to electrolysis in the electrolysis tank 2 under the set electrolysis treatment conditions (S102). 【0063】 While the electrolysis treatment is being performed, the control means 5 acquires the value of the electrochemical change of the water to be treated WW measured by the residual chlorine response means 4 (S103). At this time, for example, if the value of the electrochemical change of the water to be treated WW does not show an increasing trend, the amount of current / voltage supplied to the electrode 6 is increased to strengthen the degree of electrolysis treatment, and if the value of the electrochemical change immediately shows an increasing trend, the amount of current / voltage supplied to the electrode 6 is decreased to weaken the degree of electrolysis treatment. 【0064】 The control means 5 terminates the electrolysis treatment by stopping the current supply to the electrode 6, using the endpoint where the value of the electrochemical change of the treated water WW plateaus as an indicator, based on the trend of the value of the electrochemical change (S104). 【0065】 After the electrolysis process is completed, the electrolyzed water outlet valve 7b is opened to discharge the electrolyzed water EW obtained by the electrolysis process from the electrolysis tank 2 (S105). 【0066】 Figure 5 is a layout diagram of a water treatment electrolysis system 10 according to another embodiment of the present invention. In the water treatment electrolysis system 10, the residual chlorine response means 4 is integrally incorporated into the electrolysis tank 2. 【0067】 An electrolysis system for water to be treated according to one aspect of the present invention can be incorporated, for example, into a wastewater treatment system. Figure 6 is a layout diagram of a wastewater treatment system 100 incorporating the electrolysis system 1 for water to be treated. The wastewater treatment system 100 sends wastewater through a wastewater tank to a treatment tank (chemical treatment tank, biological treatment tank, etc.) for wastewater treatment. The primary treated water treated in the treatment tank is then sent to the electrolysis system 1 for water to be treated via a separation membrane. The electrolyzed water obtained by electrolysis in the electrolysis system 1 for water to be treated is sent to a membrane separation means via an intermediate tank. The permeate from the membrane separation means is stored in a treated water tank and used as purified water. 【0068】 A wastewater treatment system is any system that treats wastewater flowing in from outside the system and then supplies the resulting treated water as purified water to the outside. A wastewater treatment system may be a building wastewater treatment system installed in a residence, small commercial facility, factory plant, temporary facility, etc., or it may be a portable wastewater treatment system that can be moved. Among wastewater treatment systems, a device that connects to the drainage system of a building, treats the wastewater flowing in from the drainage system, and returns the resulting treated water as purified water to the drainage system, that is, a device that regenerates and circulates water between the building's drainage system and the wastewater treatment system, is called a self-sustaining circulating wastewater treatment system, and when the building is a residence such as a house, it is called a self-sustaining circulating residential wastewater treatment system. 【0069】 It should be noted that the present invention is not limited to any of the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above embodiments. For example, some components from all the components shown in the embodiments may be modified by addition, deletion, substitution, etc. Moreover, components and forms from different embodiments may be appropriately combined. [Industrial applicability] 【0070】 A system and method according to one aspect of the present invention can be used to kill pathogens contained in treated water and produce water with a reduced number of pathogens or that is pathogen-free. These systems and methods can be used to supply water users with safe and reliable water. [Explanation of symbols] 【0071】 1. 10 Electrolysis system for treated water 2. Electrolysis cell 4. Residual chlorine response means 5. Control means 51 Processing Unit 52 Storage section 521 Index Values 522 Signal History 523 Configuration Program 524 Update 525 Calculation Program 53 Input / output section 54 bus 6 electrodes 7a Inlet valve for treated water 7b Electrolyzed water outlet valve

Claims

[Claim 1] An electrolysis system for water to be treated, The system comprises an electrolysis cell, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the value of the electrochemical change in the water to be treated contained in the electrolysis tank, and The control means performs the electrolysis treatment to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before the electrolysis treatment, and detects the point at which the value of the electrochemical change after the free residual halogen in the water to be treated has been consumed by the decomposition of organic matter, as measured by the residual chlorine response means, begins to rise, as the starting point for the generation of free residual halogen, and further controls the termination of the electrolysis treatment based on the integral value of the electrochemical change, and The value of the electrochemical change is at least one value selected from the group consisting of voltage values ​​and current values. The aforementioned system. [Claim 2] A method for electrolyzing water to be treated, A step of performing electrolysis to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before electrolysis treatment, A step of measuring the value of the electrochemical change of the water to be treated during the electrolysis treatment, The process involves detecting the point at which the value of the electrochemical change after the measured free residual halogen in the treated water has been consumed by the decomposition of organic matter begins to rise as the starting point for the generation of free residual halogen, and further determining the termination of the electrolysis treatment based on the integral value of the electrochemical change. including, and The value of the electrochemical change is at least one value selected from the group consisting of voltage values ​​and current values. The aforementioned method. [Claim 3] A sterilization treatment system for water to be treated, The system comprises an electrolysis cell, a residual chlorine response means, and a control means. The electrolysis tank is capable of subjecting the contained water to be treated to electrolysis treatment. The residual chlorine response means is capable of measuring the value of the electrochemical change in the water to be treated contained in the electrolysis tank, and The control means performs the electrolysis treatment to generate halogen oxygen acids from halides and / or halide ions in the water to be treated before the electrolysis treatment, and to sterilize microorganisms in the water to be treated with the generated halogen oxygen acids, and detects the point at which the value of the electrochemical change after the free residual halogen in the water to be treated has been consumed by the decomposition of organic matter, as measured by the residual chlorine response means, begins to rise, as the starting point for the generation of free residual halogen, and further controls the termination of the electrolysis treatment based on the integral value of the electrochemical change, and The value of the electrochemical change is at least one value selected from the group consisting of voltage values ​​and current values. The aforementioned system. [Claim 4] A method for sterilizing water to be treated, A step of generating halogenated oxygen acids from halides and / or halide ions in the water to be treated before electrolysis treatment, and performing electrolysis treatment to sterilize microorganisms in the water to be treated with the generated halogenated oxygen acids, A step of measuring the value of the electrochemical change of the water to be treated during the electrolysis treatment, The process involves detecting the point at which the value of the electrochemical change after the measured free residual halogen in the treated water has been consumed by the decomposition of organic matter begins to rise as the starting point for the generation of free residual halogen, and further determining the termination of the electrolysis treatment based on the integral value of the electrochemical change. including, and The value of the electrochemical change is at least one value selected from the group consisting of voltage values ​​and current values. The aforementioned method.

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