Water treatment method and water treatment system

Abstract

Provided is a water treatment method and the like that enables stable management of water systems. [Solution] According to one aspect of the present invention, there is provided a water treatment method for an aqueous system, comprising a supplying step and a control step, in which the supplying step supplies hypochlorite ions to the aqueous system to be treated, the aqueous system containing a bromide salt and a chlorine stabilizer, and the control step controls the concentration of hypobromite ions in the aqueous system to be treated at one or more of the timings before, during, and after the supplying step.

Description

[Technical Field]

[0001] The present invention relates to a water treatment method and a water treatment system. [Background technology]

[0002] In various water systems such as heat storage water systems, paper pulp process water systems, dust collection water systems, and scrubber water systems, hypohalous acids (e.g., hypochlorous acid, hypobromous acid, etc.) are sometimes used to prevent biofouling, prevent slime formation, and kill microorganisms (e.g., bacteria, fungi, algae, etc.) inside the piping and filtration membranes of the water system. As an example, hypohalous acids may be passed through open circulating cooling water to achieve the above-mentioned effects. Among these hypohalous acids, hypobromous acid has a stronger bactericidal effect than hypochlorous acid, and therefore the use of hypobromous acid in water systems has attracted attention.

[0003] In this regard, a technique disclosed in Patent Document 1 is also known. According to Patent Document 1, biofouling can be controlled by preparing a first composition and a second composition and administering them to industrial water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2009-513337 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors have found through their investigations that there are cases where more stable management is required when treating a target water system.

[0006] In view of the above circumstances, the present invention provides a water treatment method and the like that can stably manage a water system. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a water treatment method for an aqueous system, the method comprising a supplying step and a control step, in which the supplying step supplies hypochlorite ions to the aqueous system to be treated, the aqueous system containing a bromide salt and a chlorine stabilizer, and the control step controls the concentration of hypobromite ions in the aqueous system to be treated at one or more timings selected from the group consisting of before, during, and after the supplying step.

[0008] According to the above aspect, a water treatment method and the like that can stably manage a water system are provided.

[0009] Furthermore, it may be provided in the following aspects.

[0010] (1) A water treatment method for an aqueous system, comprising a supplying step and a control step, wherein in the supplying step, hypochlorite ions are supplied to the aqueous system, the aqueous system containing a bromide salt and a chlorine stabilizer, and the control step controls the concentration of hypobromite ions in the aqueous system at one or more of the timings before, during, and after the supplying step.

[0011] (2) The water treatment method according to (1) above, wherein the control step controls the concentration of the hypobromite ions to be 5 mg / L or less in terms of chlorine.

[0012] (3) The water treatment method according to (1) or (2) above, wherein the chlorine stabilizer contains a sulfamic acid compound.

[0013] (4) The water treatment method according to any one of (1) to (3) above, wherein the target water system has a contact point with a metal component.

[0014] (5) The water treatment method according to any one of (1) to (4) above, further comprising a pretreatment step, in which hypochlorite ions are removed from the water contained in the water system, and in the management step, a means for measuring hypohalite ions is applied to the water that has been subjected to the pretreatment step, thereby identifying and managing the concentration of hypobromite ions.

[0015] (6) The water treatment method according to any one of (1) to (5) above, wherein the concentration of bromide ions in the target water system is in the range of 5 to 20 mg / L.

[0016] (7) The water treatment method according to any one of (1) to (6) above, wherein, when the amount of hypochlorite ions supplied in the supply step is X [mol] and the amount of the chlorine stabilizer contained in the water system is Y [mol], Y / X is in the range of 2 to 4.

[0017] (8) A water treatment system for an aqueous system, comprising a supply unit and a measurement unit, wherein the supply unit supplies hypochlorite ions to the aqueous system, wherein the aqueous system to be supplied contains a bromide salt and a chlorine stabilizer, and the measurement unit measures the concentration of hypobromite ions in the aqueous system at one or more of the following times: before, during, and after the supply unit supplies the hypochlorite ions.

[0018] (9) In the water treatment system described in (8) above, the supply unit controls the supply mode of the hypochlorite ions based on the concentration value of the hypobromite ions measured by the measurement unit. Of course, this is not the case. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing the overall configuration of a water treatment system according to an embodiment of the present invention. [Figure 2]FIG. 2 is a diagram illustrating a hardware configuration of an information processing device 3. [Figure 3] 1 is a graph plotting the concentration of hypobromite ions and hypochlorite ions in an example. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described. Note that the various features shown in the following embodiments can be combined with each other. Note that in this specification, "to" means "above" through "below" unless otherwise specified.

[0021] That is, the water treatment method of this embodiment is as follows. A water treatment method for a water system, comprising: The method includes a supplying process and a management process, In the supplying step, hypochlorite ions are supplied to the target aqueous system, wherein the aqueous system to be supplied contains a bromide salt and a chlorine stabilizer; In the management step, the concentration of hypobromite ions in the target aqueous system is managed at one or more of the timings before, during, and after the supply step.

[0022] Incidentally, the program for realizing the software appearing in one embodiment may be provided as a non-transitory computer-readable medium, or may be provided so that it can be downloaded from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0023] Furthermore, various information processing according to an embodiment may realize input and output corresponding to the input. Here, the form of information referenced in such information processing (hereinafter referred to as reference information) is not limited as long as an output is obtained as a result of the input. The reference information may be, for example, rule-based information such as a database, a lookup table, or a predetermined function (including a decision formula such as a regression formula constructed using a statistical method), a trained model that has previously trained the correlation between input and output, or a generative AI such as a large-scale language model or a visual language model that can output a desired result in response to a prompt input.

[0024] In one embodiment, a "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In one embodiment, various information is handled, and this information is represented, for example, by physical values ​​of signal values ​​representing voltage and current, high and low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations can be performed on a circuit in the broad sense.

[0025] Furthermore, a circuit in the broad sense is a circuit realized by at least an appropriate combination of a circuit, circuitry, processor, memory, etc. The processor may be a general-purpose processor or a dedicated circuit. That is, it includes an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0026] 1. Overall structure In this section, the overall configuration of a water treatment system related to the water treatment method according to this embodiment will be described. Fig. 1 is a diagram showing the overall configuration of the water treatment system according to this embodiment.

[0027] That is, the water treatment system 100 exemplified in this embodiment treats aqueous WS. Here, the water treatment system 100 may include a supply unit 1 and a measurement unit 2. The water treatment system 100 shown in FIG. 1 is also described as including an information processing device 3 capable of performing predetermined arithmetic processing. While FIG. 1 depicts the water treatment system 100 as including an "aqueous WS," "water treatment" may also refer to performing predetermined processing on aqueous WS. Therefore, the configuration excluding the aqueous WS (the combination of the supply unit 1, the measurement unit 2, and the information processing device 3) may also be referred to as a "water treatment system." On the other hand, the combination of the supply unit 1 and the measurement unit 2 (or a combination including the aqueous WS) that essentially performs processing on the aqueous WS may also be referred to as a "water treatment system."

[0028] In this embodiment, the supply unit 1 is configured to be able to supply hypochlorite ions to the target aqueous solution. Specifically, in the example shown in FIG. 1, a combination of a tank 11 capable of storing a hypochlorite ion supply source and a valve 12 used to supply the agent (hypochlorite ion supply source) stored in the tank 11 to the aqueous solution is shown as an example of the supply unit 1. In this embodiment, the aqueous solution to be supplied contains a bromide salt and a chlorine stabilizer. The technical background for adopting such a supply mode will be explained later.

[0029] Meanwhile, the measurement unit 2 measures the concentration of hypobromite ions in the target aqueous WS at one or more of the following times: before, during, and after the supply unit 1 supplies hypochlorite ions. That is, the inventors have found that the concentration of hypobromite ions in the aqueous WS can cause problems such as corrosion of materials in contact with the aqueous WS. Therefore, it is effective to use the function of the measurement unit 2 to control the concentration of hypobromite ions in the aqueous WS.

[0030] The water system WS of this embodiment may be any of various systems in which water is stored, passed through, or circulated. Typical examples include, but are not limited to, various water systems such as a heat storage water system, a paper pulp process water system, a dust collection water system, and a scrubber water system.

[0031] In this embodiment, the concentration of hypobromite ions in the aqueous solution is controlled, but the aqueous solution may have contact points with metal components. That is, even when the aqueous solution has contact points with metal components, the concentration of hypobromite ions in the aqueous solution can be easily controlled to a predetermined value, thereby facilitating the construction of a stable process. The metal species constituting the metal component in contact with the aqueous solution may be selected as appropriate, and examples include iron, gold, silver, copper, aluminum, zinc, tin, chromium, nickel, alloys containing these metals, plated steel, or vapor-deposited products made of these metals. In one aspect, the metal component may have a surface made of copper or a copper alloy, and this surface may be configured to contact the aqueous solution.

[0032] Furthermore, the example of the water treatment system 100 of this embodiment shows an aspect including an information processing device 3 for performing predetermined control.

[0033] 2 is a diagram showing the hardware configuration of the information processing device 3. The information processing device 3 has a control unit 31, a storage unit 32, a communication unit 33, a display unit 34, and an input unit 35, and is configured by electrically connecting these units via a communication bus 30. Each unit provided in the information processing device 3 will be described below.

[0034] (control unit 31) The control unit 31 is, for example, a central processing unit (CPU) not shown. The control unit 31 realizes various functions related to the information processing device 3 by reading out predetermined programs stored in the storage unit 32. In other words, information processing by software stored in the storage unit 32 is specifically realized by the control unit 31, which is an example of hardware, and can be executed as each functional unit included in the control unit 31. Note that the control unit 31 is not limited to being single, and multiple control units 31 may be provided for each function. A combination of these may also be used.

[0035] Specifically, the control unit 31 may be provided with the following functional units. That is, the acquisition unit 311, which constitutes a part of the control unit 31, is configured to acquire predetermined information from an external device or the like via the communication unit 33. In the example of this embodiment, it is configured to be able to acquire parameters measured by the measurement unit 2. The supply control unit 312, which constitutes a part of the control unit 31, is configured to control the supply mode of the supply unit 1 based on the acquired parameters or the like. Specific processing related to the control of this supply mode will be described later. Furthermore, the display control unit 313, which constitutes a part of the control unit 31, is configured to display predetermined visual information or the like on the display unit 34 or the like of the information processing device 3. Specifically, the display control unit 313 may transmit a signal to the display unit 34 or the like, thereby causing the predetermined information to be displayed on the display unit 34. Note that the medium for displaying the visual information is not limited to the display unit 34 of the information processing device 3. For example, visual information can also be displayed on an external device by transmitting a signal to the external device via the communication unit 33.

[0036] (Storage unit 32) The memory unit 32 stores various pieces of information defined above. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs and the like related to the information processing device 3 executed by the control unit 31, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to the program operations. The memory unit 32 stores various programs, variables, etc. related to the information processing device 3 executed by the control unit 31.

[0037] (Communications Department 33) The communication unit 33 is configured to be able to transmit various electrical signals from the information processing device 3 to external components. The communication unit 33 is also configured to be able to receive various electrical signals from the external components to the information processing device 3. The communication unit 33 may have a network communication function, which allows various pieces of information to be communicated between the information processing device 3 and external devices via a communication line.

[0038] (Display section 34) The display unit 34 may be, for example, included in the housing of the information processing device 3, or may be externally attached. The display unit 34 displays a graphical user interface (GUI) screen that can be operated by the user. This is preferably implemented by selectively using display devices such as a CRT display, a liquid crystal display, an organic EL display, and a plasma display depending on the type of the information processing device 3.

[0039] (Input unit 35) The input unit 35 may be included in the housing of the information processing device 3 or may be externally attached. For example, the input unit 35 may be implemented as a touch panel integrated with the display unit 34. The touch panel allows the user to input tapping, swiping, and the like. Of course, switch buttons, a mouse, a QWERTY keyboard, and the like may be used instead of the touch panel. That is, the input unit 35 accepts an operation input made by the user. The input is transferred as a command signal to the control unit 31 via the communication bus 30, and the control unit 31 can execute predetermined control or calculation as necessary.

[0040] 2. Details of water treatment method In this section, the water treatment method according to this embodiment will be described in detail. As described above, the water treatment method according to this embodiment includes a supplying step and a managing step. Each step will be described in detail below.

[0041] [Supply process] The supply step performed in the water treatment method of this embodiment supplies hypochlorite ions to the target aqueous solution (WS), which contains a bromide salt and a chlorine stabilizer.

[0042] That is, in the supply step of this embodiment, hypochlorite ions are supplied to the aqueous WS. However, because the aqueous WS contains bromide salts, hypobromite ions may be generated within the aqueous WS. The generation of these hypobromite ions can significantly enhance the effects of preventing biofouling, slime formation, and killing microorganisms (e.g., bacteria, fungi, algae, etc.). Meanwhile, the present inventors have focused on the concern that the generated hypobromite ions may corrode components (metal components, etc.) involved in the aqueous WS, and have devised a method of incorporating a chlorination stabilizer into the aqueous WS. By employing this method, the supplied hypochlorite ions can at least partially act on the chlorine stabilizer in the aqueous WS, making them less likely to be directly converted to hypobromite ions. This can be said to facilitate the prevention of excessively high hypobromite ion concentrations within the aqueous WS. Furthermore, as the hypobromite ions are consumed, the hypochlorite ions that have acted on the chlorine stabilizer gradually dissociate and react with the bromide ions in the aqueous WS. This regenerates the hypobromite ions, making it possible to achieve the aforementioned slime prevention effect over a long period of time. The bromide salt and the chlorine stabilizer may be added to the aqueous WS prior to the supply process.

[0043] In the supply step of this embodiment, the aqueous WS contains a bromide salt. The bromide salt is not particularly limited, and examples thereof include alkali metal bromide salts, ammonium bromide salts, hydrobromic acid salts, and amine bromide salts, and one or more selected from these can be used.

[0044] The alkali metal bromide salt is not particularly limited, but examples thereof include sodium bromide, potassium bromide, lithium bromide, etc., and one or more selected from these can be used. The amine bromide salt (a linear, branched, or cyclic alkyl or alkenyl group having 1 to 6 carbon atoms) is not particularly limited, but examples thereof include diethylamine hydrogen bromide, allylamine hydrogen bromide, cyclohexylamine hydrogen bromide, monomethylamine hydrogen bromide, dimethylamine hydrogen bromide, trimethylamine hydrogen bromide, n-butylamine hydrogen bromide, and ethylamine hydrogen bromide, and one or more selected from these can be used.

[0045] The amount of bromide salt contained in the aqueous solution can be set as desired. From the viewpoint of stably generating hypobromite ions in the aqueous solution, the concentration of bromide ions in the aqueous solution is preferably set in the range of 5 to 20 mg / L, and more preferably in the range of 5 to 10 mg / L.

[0046] In the supplying step of this embodiment, the aqueous WS contains a chlorine stabilizer. Examples of the chlorine stabilizer include a compound having a primary amino group, ammonia, and an ammonium salt (hereinafter, these may be referred to as "NH2-based compounds"). One or more of these may be used.

[0047] The compound having a primary amino group is not particularly limited, but examples thereof include aliphatic amines, aromatic amines, sulfamic acid, sulfanilic acid, sulfamoylbenzoic acid, amino acids, etc., and one or more compounds selected from these may be used.

[0048] Examples of ammonium salts include ammonium chloride and ammonium sulfate, and one or more selected from these can be used.

[0049] Specific examples of the chlorine stabilizer include sulfamic acid compounds; isocyanuric acid; hydantoins such as 5,5'-dimethylhydantoin; amide compounds such as urea, biuret, methyl carbamate, ethyl carbamate, acetamide, nicotinamide, methanesulfonamide, and toluenesulfonamide; imide compounds such as maleimide, succinimide, and phthalimide; amino acids such as glycine, alanine, histidine, and lysine; amine compounds such as methylamine, hydroxylamine, morpholine, piperazine, imidazole, and histamine; ammonia; and ammonium salts such as ammonium sulfate. One or more types selected from these can be used.

[0050] In this embodiment, among these chlorine-based stabilizers, it is preferable to add a sulfamic acid compound to the aqueous WS from the viewpoint of ease of handling, etc. Examples of the sulfamic acid compound include sulfamic acid, sulfamic acid derivatives, and salts thereof, and one or more selected from these can be used.

[0051] Among chlorine stabilizers (preferably NH2-based compounds), sulfamic acid (more preferably NH2SO2OH) is preferred. When monochlorosulfamine is produced using sulfamic acid, it becomes a stable chloramine compound, which is preferable.

[0052] The sulfamic acid compound may be a compound represented by the following general formula [1] or a salt thereof.

[0053] [ka] (However, in the general formula [1], R 1 and R 2 are each independently hydrogen or a hydrocarbon group having 1 to 8 carbon atoms.

[0054] Examples of such sulfamic acid compounds include R 1 and R 2In addition to sulfamic acid in which both are hydrogen, examples include N-methylsulfamic acid, N,N-dimethylsulfamic acid, N-phenylsulfamic acid, etc., and one or more selected from these can be used.

[0055] Examples of the sulfamic acid derivatives include N-methylsulfamic acid, N,N-dimethylsulfamic acid, and N-phenylsulfamic acid.

[0056] The salt of the compound used in the chlorine stabilizer is not particularly limited, and examples thereof include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts, strontium salts, and barium salts; other metal salts such as manganese salts, copper salts, zinc salts, iron salts, cobalt salts, and nickel salts; amine salts such as ammonium salts and guanidine salts, and amino acid salts. One or more selected from these can be used. Among these, alkali metal salts (preferably sodium) are preferred from the viewpoints of cost and ease of handling. The salts of these compounds can be used as salts of sulfamic acid compounds.

[0057] On the other hand, in the supplying step of this embodiment, hypochlorite ions are supplied to the aqueous WS containing the predetermined agent. The hypochlorite ions may be supplied in various ways, for example, one or more compounds selected from the group consisting of hypochlorous acid or its salt, and chlorinated isocyanuric acid or its salt are supplied to the aqueous WS.

[0058] Among these, hypochlorites are not particularly limited, but include alkali metal hypochlorites such as sodium hypochlorite and potassium hypochlorite; alkaline earth metal hypochlorites such as calcium hypochlorite and barium hypochlorite; and one or more selected from these can be used.

[0059] On the other hand, examples of chlorinated isocyanuric acid that can be used include monochloroisocyanuric acid, dichloroisocyanuric acid, and trichloroisocyanuric acid. These compounds can supply hypochlorous acid by hydrolysis with water, and therefore can function as a source of hypochlorite ions. When a salt of chlorinated isocyanuric acid is used, the salt may be any suitable salt, and examples thereof include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts, strontium salts, and barium salts; other metal salts such as manganese salts, copper salts, zinc salts, iron salts, cobalt salts, and nickel salts; amine salts such as ammonium salts and guanidine salts; and amino acid salts.

[0060] Hypochlorite ions may be supplied to the aqueous WS by various methods. Regarding the configuration shown in FIG. 1, the supply step of this embodiment may be realized by storing the various compounds described above in a tank 11 of the supply unit 1 and supplying them to the aqueous WS. The compounds stored in the tank 11 may be stored in liquid or solid form. When stored in liquid form, the compounds themselves are not limited to being liquid, and solid compounds may be dissolved in a solvent such as water.

[0061] In the supply step of this embodiment, the amount of hypochlorite ions supplied may be appropriately set depending on the type of process, etc. Meanwhile, from the viewpoint of significantly exhibiting the aforementioned slime prevention effect, etc., it is preferable to supply a predetermined compound to the aqueous WS so as to satisfy the following relational expression: That is, when the amount of hypochlorite ions supplied in the supply step is X [mol] and the amount of chlorine stabilizer contained in the aqueous WS is Y [mol], Y / X is preferably in the range of 2 to 4, and more preferably Y / X is in the range of 2 to 3. Note that the supply amount of hypochlorite ions here may be defined based on the amount of hypochlorite ions supplied to the aqueous WS per cycle, for example, when the predetermined compound is intermittently added to the aqueous WS. The time interval for one cycle may be set depending on the type and scale of the process involving the aqueous WS, but as an example, a time interval selected from the range of 1 to 48 hours or a time interval selected from the range of 1 to 24 hours can be used (for example, an embodiment in which hypochlorite ions are supplied to the aqueous WS every 6 hours, every 12 hours, or every 24 hours is exemplified).

[0062] Although not described in detail above, the aqueous solution to which the supply step is carried out may contain other agents not mentioned above, provided that such addition does not depart from the spirit and scope of the present invention. For example, the aqueous solution may contain a pH adjuster (acid and / or alkali), an antifoaming agent, an anticorrosive (corrosion inhibitor), a scale inhibitor, a dispersant, an enzyme, etc.

[0063] [Management process] In the control step of this embodiment, the concentration of hypobromite ions in the target aqueous WS is controlled at one or more of the timings before, during, and after the supply step. That is, the water treatment method of this embodiment is characterized by controlling the concentration of hypobromite ions in the water present in the aqueous WS, in consideration of the fact that hypobromite ions contained in the aqueous WS can corrode materials. Note that "control" here refers to manually and / or automatically grasping the level of the concentration of hypobromite ions in the water present in the aqueous WS. From this perspective, the term "control" in this specification may be interpreted as "monitoring," "detection," "measurement," "quantification," etc.

[0064] Explaining the configuration shown in FIG. 1 , the management process of this embodiment may be realized by the function of a measurement unit 2 provided in contact with the water of the aqueous system WS. That is, the measurement unit 2 may have various configurations capable of measuring the concentration of hypobromite ions contained in water, thereby enabling the management process of this embodiment to be performed. The concentration of hypobromite ions measured by the measurement unit 2 may be transferred to an information processing device 3 configured to be able to communicate with the measurement unit 2. That is, the acquisition unit 311 of the information processing device 3 can acquire the concentration of hypobromite ions measured by the measurement unit 2, and, for example, can display the measured concentration of hypobromite ions on the display unit 34 of the information processing device 3 based on the function of the display control unit 313.

[0065] Furthermore, the timing at which the control step performs control (measurement, etc.) is one or more of before, during, and after the supply step. For example, the concentration of hypobromite ions may be controlled (measured, etc.) after hypochlorite ions are supplied to the aqueous WS, or the concentration of hypobromite ions in the aqueous WS may be controlled (measured, etc.) continuously or intermittently from before the supply step to after the supply step. For example, a typical aspect of the control step of this embodiment is an aspect in which the concentration of hypobromite ions in the aqueous WS is continuously plotted before and after the supply of hypochlorite ions.

[0066] In the control step of this embodiment, the control value and control range of the hypobromite ion concentration can be appropriately set depending on the type of process to be applied. On the other hand, from the viewpoint of establishing a more stable process for aqueous WS, the control step preferably controls the hypobromite ion concentration to 5 mg / L or less, more preferably 3 mg / L or less, and even more preferably 1 mg / L or less, in terms of chlorine equivalent. For example, when the water in the aqueous WS is in contact with a metal component such as copper, setting the above-mentioned control value can further suppress corrosion of the metal component. The lower limit of the hypobromite ion concentration is not particularly limited, but an example is 0.01 mg / L or more. The "chlorine equivalent concentration" here can be determined based on the equivalent amount as an oxidizing agent. Specifically, a hypobromite ion concentration of 1 mmol / L can be evaluated as a chlorine equivalent concentration of 70.9 mg / L.

[0067] That is, in the water treatment method of this embodiment, by employing the management method described above, it is possible to establish a stable process including an aqueous WS.

[0068] Prior to carrying out such a management step, the following pre-processing step may be carried out.

[0069] [Pretreatment process] That is, in the pretreatment step that can be included in the water treatment method of this embodiment, hypochlorite ions are removed from the water contained in the aqueous system WS. Then, in the control step, the concentration of hypobromite ions in the water that has been subjected to the pretreatment step may be specified and controlled by applying a means for measuring hypohalite ions.

[0070] Generally, the DPD method (diphenylamine method) and the like are sometimes used to quantify the concentrations of hypochlorite ions and hypobromite ions. In this regard, since DPD reagents (DPD-free reagents) can react with both hypochlorite ions and hypobromite ions (all hypohalite ions), it is preferable to remove hypochlorite ions from water as a pretreatment when determining the concentration of hypobromite ions. Various methods for removing hypochlorite ions may be used, but a typical example is adding a compound that selectively reacts with hypochlorite ions to the water in the aqueous solution system to be measured. Examples of such compounds include compounds with amino groups, and among these, amino acids such as glycine are preferred from the perspective of ease of handling. The quantification of the concentrations of hypochlorite ions and hypobromite ions using the DPD method may be performed in accordance with JIS K 0400-33-10:1999, etc.

[0071] In addition, when the measurement is performed by the DPD method without using a compound that selectively acts on hypochlorite ions, the concentration of the "sum of hypochlorite ions and hypobromite ions (total hypohalite ions)" in the water contained in the aqueous WS can be determined. Based on this sum and the value of the above-mentioned "hypobromite ion concentration," it is also possible to determine the concentration of hypochlorite ions in the water of the aqueous WS.

[0072] Furthermore, in the management method including such a pretreatment step, the pretreatment step may be automated, for example, to enable automatic measurement of hypobromite ions.

[0073] In addition, when the water treatment system 100 shown in FIG. 1 is configured as shown in FIG. 1, the following control steps may be performed.

[0074] [Control process] That is, in the control step of this embodiment, the supply unit 1 provided in the water treatment system 100 may control the supply mode of hypochlorite ions based on the concentration value of hypobromite ions measured by the measurement unit 2. That is, the information processing device 3 provided in the water treatment system 100 may include an acquisition unit 311 and a supply control unit 312. In this case, the supply mode of hypochlorite ions provided by the supply unit 1 may be controlled based on the concentration value of hypobromite ions acquired by the acquisition unit 311. This supply mode control may be performed by various methods, for example, by controlling the supply amount and supply rate of a component that serves as a hypochlorite ion supply source. As one example, the supply control unit 312 of the information processing device 3 sends a predetermined signal to the valve 12 provided in the supply unit 1 to control the opening and closing (or the degree of opening and closing) of the valve 12, thereby adjusting the supply amount and supply rate of the component that serves as a hypochlorite ion supply source. This facilitates the establishment of a stable process for aqueous WS. In this embodiment, the information processing device 3 acquires a parameter (hypobromite ion concentration) and performs predetermined control, but the supply mode of hypochlorite ions may be controlled independently of the function of the information processing device 3. For example, by constructing a predetermined circuit or the like, it is possible to control the supply mode of hypochlorite ions based on the hypobromite ion concentration in the aqueous system WS.

[0075] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0076] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0077] [Supply of hypochlorite ions] The target water system contained 64 mg / L sulfamic acid and 31.1 mg / L bromide ions, and an aqueous solution containing trichloroisocyanuric acid was added once a day to achieve a chlorine-equivalent concentration of 1 mg / L. The target water system had a pH of 9.0, M alkalinity of 500 mg / L (as CaCO3), and calcium hardness of 500 mg / L (as CaCO3).

[0078] [Quantitative determination of hypobromite ion concentration] The hypobromite ion concentration of the target water system was periodically quantified. Before measuring the hypobromite ion concentration in water, hypochlorite ions contained in samples collected from the water system were removed. Specifically, samples collected from the water system were reacted with glycine, and the remaining hypobromite ions in the samples were then quantified using a DPD-free reagent. The measurements were performed in accordance with JIS K 0400-33-10:1999, using the DPD method with N,N-diethyl-1,4-phenylenediamine as the reagent. The reaction between hypochlorite ions and glycine was performed according to the method described on page 96 of JIS K 0101:1998.

[0079] [result] The results of this example are shown in Figure 3. Figure 3 is a graph plotting the concentrations of hypobromite ions and hypochlorite ions in this example. The concentration of hypochlorite ions in the aqueous system was calculated by measuring the total concentration of hypohalite ions in the aqueous system using a DPDfree reagent without the action of glycine, and then subtracting the concentration of hypobromite ions from the total concentration. As can be seen from the results in Figure 3, during the period in which this example was carried out, almost no hypochlorite ions were detected, and the concentration of hypobromite ions tended to increase gradually. Meanwhile, Figure 3 shows the chlorine-equivalent concentration (addition theoretical concentration) of the active ingredient based on the amount of trichloroisocyanuric acid added, but the concentration of hypobromite ions was about half of this theoretical concentration, supporting the idea that the aqueous system did not have an excessive hypobromite ion concentration. Furthermore, by controlling the concentration of hypobromite ions in the aqueous system as in this example, it is suggested that, for example, it is possible to control the effects on components (metal components, etc.) that come into contact with the aqueous system. Therefore, it can be said that the present invention stabilizes processes related to aqueous systems. [Explanation of symbols]

[0080] 1: Supply section 2: Measuring part 3: Information processing equipment 11: Tank 12: Valve 30: Communication bus 31: Control unit 32: Storage section 33: Communications Department 34:Display section 35: Input section 100: Water treatment system 311: Acquisition Department 312: Supply control unit 313: Display control unit WS: Water-based

Claims

1. A water treatment method for a water system, comprising: The method includes a supplying process and a management process, In the supplying step, hypochlorite ions are supplied to the target aqueous system, wherein the aqueous system to be supplied contains a bromide salt and a chlorine stabilizer; In the management step, the concentration of hypobromite ions in the target aqueous system is managed at one or more timings of before, during, and after the supply step, thereby controlling the supply mode of hypochlorite ions.

2. The water treatment method according to claim 1, In the control step, the concentration of the hypobromite ions is controlled to be 5 mg / L or less in terms of chlorine concentration.

3. The water treatment method according to claim 1, The water treatment method, wherein the chlorine stabilizer comprises a sulfamic acid compound.

4. The water treatment method according to claim 1, A water treatment method, wherein the target water system has a contact point with a metal component.

5. The water treatment method according to claim 1, Further, a pre-treatment step is provided, In the pretreatment step, hypochlorite ions are removed from the water contained in the aqueous system, In the management step, the concentration of hypobromite ions in the water that has been subjected to the pretreatment step is identified and managed by applying a means for measuring hypohalite ions.

6. The water treatment method according to claim 1, A water treatment method, wherein the concentration of bromide ions in the target water system is in the range of 5 to 20 mg / L.

7. The water treatment method according to claim 1, The water treatment method, wherein Y / X is in the range of 2 to 4, where X [mol] is the amount of hypochlorite ions supplied in the supply step and Y [mol] is the amount of the chlorine stabilizer contained in the aqueous system.

8. A water treatment system for a water system, A supply unit, a measurement unit, and an information processing device, The supply unit supplies hypochlorite ions to the target water system, wherein the aqueous system to be supplied contains a bromide salt and a chlorine stabilizer; The measurement unit measures the concentration of hypobromite ions in the target aqueous system at any one or more timings of before, during, and after the supply unit supplies the hypochlorite ions, the information processing device includes an acquisition unit and a supply control unit; the acquisition unit acquires a value of the concentration of hypobromite ions in the water system measured by the measurement unit, The supply control unit sends a signal to the supply unit based on the value of the concentration of hypobromite ions acquired by the acquisition unit, and controls the supply mode of the hypochlorite ions from the supply unit.

9. In the water treatment system according to claim 8, The supply control unit controls the supply amount or supply speed of the supply unit.

10. A water treatment method using the water treatment system according to claim 8 or claim 9, The supply unit supplies hypochlorite ions to the target water system, wherein the aqueous system to be supplied contains a bromide salt and a chlorine stabilizer; The measurement unit measures the concentration of hypobromite ions in the target aqueous system at any one or more timings of before, during, and after the supply unit supplies the hypochlorite ions, the acquisition unit acquires a value of the concentration of hypobromite ions in the water system measured by the measurement unit, The water treatment method, wherein the supply control unit sends a signal to the supply unit based on the value of the concentration of hypobromite ions acquired by the acquisition unit, and controls the supply mode of the hypochlorite ions from the supply unit.

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