Operation method of reverse osmosis membrane device, slime control method, and water treatment device

Abstract

This invention provides a technology that enables water systems equipped with reverse osmosis membrane devices to operate more stably over a longer period. The invention provides a method for operating a reverse osmosis membrane device, a method for controlling slime in a reverse osmosis membrane device, and a water treatment apparatus for implementing the method. The method for operating the reverse osmosis membrane device includes: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and a second step of adding an organic slime inhibitor during periods other than those in the first step and supplying treated water containing the organic slime inhibitor to the reverse osmosis membrane device.

Description

Technical Field

[0001] This invention relates to a method for operating a reverse osmosis membrane device, a method for controlling sludge in a reverse osmosis membrane device, and a water treatment apparatus for implementing the method. Background Technology

[0002] Reverse osmosis (RO) membranes, included in reverse osmosis systems, have been used in seawater desalination, ultrapure water production, industrial water treatment, wastewater recycling, and wastewater reuse to remove ions and organic matter from raw water. However, water systems equipped with RO membranes face the following problems: microorganisms such as bacteria or fine algae in the treated water secrete extracellular substances (e.g., extracellular polysaccharides), forming slime (biofilm). This slime adheres to and accumulates on the RO membrane during water supply, or its slime increases further due to the microorganisms contained within it, resulting in biofouling (membrane clogging caused by slime, etc.).

[0003] Previously, a method for removing sludge adhering to and proliferating on the reverse osmosis membrane surface was implemented by stopping the operation of the reverse osmosis membrane unit and cleaning the reverse osmosis membrane with chemicals such as caustic soda to remove the sludge. However, this method hinders the continuous operation of the reverse osmosis membrane unit, leading to increased operating costs.

[0004] In recent years, the following method has been implemented: without stopping the operation of the reverse osmosis membrane unit, a slime inhibitor is injected into the water supply system to the reverse osmosis membrane unit to remove slime (biofilm) adhering to the reverse osmosis membrane surface. In this method, various compounds have been studied as slime inhibitors, and slime inhibition methods using them extensively have been proposed.

[0005] For example, Patent Document 1 discloses a method for producing pure water, which includes: a slime control agent addition step, in which a slime control agent is added to raw water; a membrane treatment step, in which the raw water containing the slime control agent is subjected to membrane treatment; an ultraviolet irradiation treatment step, in which the membrane-treated water is subjected to ultraviolet irradiation treatment; and an ion exchange treatment step, in which the ultraviolet irradiated water is subjected to ion exchange treatment.

[0006] In addition, Patent Document 2 discloses a method in which the slime suppression method of the reverse osmosis membrane device is a slime suppression method used in the water flow process of the treated water, and includes adding a slime inhibitor X containing 2,2-dibromo-3-nitrilopropionamide (DBNPA) and a slime inhibitor Y containing at least one of the group consisting of the following components (A) to (D) to the treated water with the pH value set to 10 or below, and a first water flow process of passing the treated water to the reverse osmosis membrane.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2009-247992

[0010] Patent Document 2: Japanese Patent Application Publication No. 2020-28865

[0011] Patent Document 3: WO 2011 / 125762

[0012] Non-patent literature

[0013] Non-patent literature 1: JS Vrouwenvelder et al., Biofouling of Spiral Wound Membrane Systems (International Water Association, IWA, 2011). Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] Typically, with prolonged continuous operation, sludge generated within the water system adheres to the reverse osmosis membrane, or microorganisms attached to the membrane further increase the sludge buildup. Therefore, the reverse osmosis membrane unit is sometimes shut down for membrane replacement or cleaning. However, after shutdown, the increased frequency of recalibration and membrane replacement / cleaning increases operating costs. Therefore, the inventors have investigated a method to ensure long-term operation by maximizing the number of days of occlusion to minimize downtime of the reverse osmosis membrane unit.

[0016] That is, the main objective of this invention is to provide a technology that enables water systems with reverse osmosis membrane devices to operate for a longer period of time.

[0017] Technical means to solve the problem

[0018] Through diligent research, the inventors have discovered that in water systems equipped with reverse osmosis membrane devices, by combining and controlling the operation of a first step of intermittently adding oxidative slime inhibitors to the treated water with a second step of adding organic slime inhibitors to the treated water, the water system can operate for a longer period. The inventors have also found that this method effectively reduces or inhibits the increase of slime within the reverse osmosis membrane, thereby better suppressing biofouling. Furthermore, the inventors have completed the present invention as follows.

[0019] This invention provides a method for operating a reverse osmosis membrane device, comprising: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0020] The second step involves adding an organic slime inhibitor during a period "at least outside the addition period of the first step," and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit. Furthermore, the "at least" in "at least outside the addition period of the first step" means that the organic slime inhibitor is added during at least "the entire period or a portion of the period outside the addition period of the first step" within both the "addition period of the first step (first intermittent addition period)" and the "period outside the addition period of the first step (first no-addition period)." For example, it can be added during both the first no-addition period and the first intermittent addition period, or it can be added only during the first no-addition period (see, for example, [reference needed]). Figure 1 and Figure 2 ).

[0021] This invention provides a slime control method for use in a reverse osmosis membrane device, comprising: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0022] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0023] The present invention provides a water treatment device that implements the operation method of the reverse osmosis membrane device or the sludge control method applied in the reverse osmosis membrane device.

[0024] The concentration of the oxidative slime inhibitor can be adjusted to be higher than that of the organic slime inhibitor.

[0025] The aforementioned oxidative slime inhibitor can be added more than once every 3 days during operation.

[0026] The oxidative slime inhibitor can be added for at least 10 minutes each time.

[0027] The oxidative slime inhibitor can be added at a concentration of 0.1 mg / L or higher using a total chlorine concentration meter.

[0028] The organic slime inhibitor can be added at a concentration of 0.01 mg / L or higher.

[0029] The effects of the invention

[0030] According to the present invention, a technique is provided that enables water systems equipped with reverse osmosis membrane devices to operate for a longer period of time. Furthermore, the effects of the present invention are not necessarily limited to those described herein, but may include any of the effects described in this specification. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating an example of the control of the first and second addition steps according to an embodiment of the present invention. a1: In the first addition step, oxidized slime inhibitors are added intermittently at equal intervals. b1: In the second addition step, organic slime inhibitors are continuously added. In this case, the organic slime inhibitors are added during periods other than at least the addition period of the first addition step. The horizontal axis represents the operating period (hours), and the vertical axis represents the amount added.

[0032] Figure 2 This is a schematic diagram illustrating an example of the control of the first and second addition steps according to an embodiment of the present invention. a2: In the first addition step, oxidized slime inhibitors are added intermittently at equal intervals. b2: In the second addition step, organic slime inhibitors are added continuously during periods other than the addition period of the first addition step. The horizontal axis represents the operating period (hours), and the vertical axis represents the amount added.

[0033] Figure 3 This is an example of a schematic diagram showing a water system having a reverse osmosis membrane device according to an embodiment of the present invention.

[0034] Figure 4 This is a graph showing the change in differential pressure (kPa) of Comparative Example 2-1 (●) and Example 2-1 (◆) during each water supply period (day) in Test Example 2.

[0035] Figure 5This is a graph showing the change in differential pressure (kPa) of Comparative Example 3-1 (●) and Example 3-1 (◆) during each water supply period (day) in Test Example 3.

[0036] [Explanation of Symbols]

[0037] 1: Water system

[0038] 2: Reverse osmosis membrane device

[0039] 3: Safety Filter

[0040] 4: Solid-liquid separation device

[0041] 5: Coagulation treatment device

[0042] 10: First reagent addition device

[0043] 20: Second reagent addition device Detailed Implementation

[0044] The following describes the configurations used to implement the present invention. Furthermore, the embodiments described below are representative examples illustrating the present invention and are not intended to limit or interpret the scope of the invention. Moreover, the upper and lower limits in the numerical values ​​can be arbitrarily combined as needed.

[0045] 1. Operation method of the reverse osmosis membrane device involved in this embodiment

[0046] This invention provides a method for operating a reverse osmosis membrane device, comprising: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0047] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0048] The slime inhibitor used in this specification is an agent that can inhibit the increase of slime. It may include agents that can reduce or remove slime present in the membrane, agents that can kill microorganisms (bactericides, algaecides, etc.), and agents that can inhibit the proliferation of microorganisms (antibacterial agents, etc.). In addition, the designations "first" and "second" in the first step, second step, etc., in this specification are added for ease of explanation. This embodiment is not narrowly limited by the addition of "first" and "second," and there is no particular limitation.

[0049] The oxidative slime inhibitors used in this embodiment are components or agents, or agents containing these as active ingredients, that can inhibit slime originating from microorganisms (e.g., bacteria, fungi, microalgae, etc.) through redox reactions. They can be detected by the N,N-diethyl-p-phenylenediamine (DPD) method. In this specification, halocyanoacetamide compounds (preferably DBNPA) are classified as organic slime inhibitors because they inhibit enzyme metabolism.

[0050] The organic slime inhibitor used in this embodiment is a component or agent that inhibits slime originating from microorganisms (e.g., bacteria, fungi, microalgae, etc.) or contains these as active ingredients by inhibiting the metabolic functions (enzymes, etc.) of microorganisms or by reacting with the cells (e.g., SH groups) of microorganisms.

[0051] 1-1. The first step in using oxidative slime inhibitors

[0052] The first step is suitable for intermittently adding oxidative slime inhibitors and intermittently supplying the treated water containing the oxidative slime inhibitors to the reverse osmosis membrane unit.

[0053] Therefore, the first process is suitable to include: a first addition process, intermittently adding an oxidative slime inhibitor to the water to be treated; and a first supply process, intermittently supplying the water containing the added oxidative slime inhibitor to the reverse osmosis membrane unit.

[0054] 1-1-1. First Addition Process

[0055] The first step is to intermittently add an oxidative slime inhibitor to the water being treated. This yields treated water containing the oxidative slime inhibitor, which can then be intermittently supplied to a reverse osmosis membrane unit (e.g., see reference). Figure 1 and Figure 2 ).

[0056] The first step is to intermittently add oxidative slime inhibitors.

[0057] The preferred frequency for adding oxidative slime inhibitors is to add them at least once within a specified period. This specified period is preferably 5 days, more preferably 4 days, further preferably 3 days, even more preferably 2 days, and even more preferably 1 day. Alternatively, "within a specified period" can be set to "every specified interval" for adding the oxidative slime inhibitors; for example, it can be added once every 3 days or once every day. Additionally, it can be added at least once every 1 to 2 days (more preferably every day).

[0058] There is no particular limitation on the number of times the oxidative slime inhibitor is added. As a suitable upper limit, it is preferably 10 times or less, more preferably 5 times or less, more preferably 3 times or less, more preferably 2 times or less, and even more preferably 1 time. The number of times added can be "during a specified period" or "every specified interval".

[0059] In terms of the frequency of adding oxidative slime inhibitors, it is preferable to add them more than once every 3 days, more preferably more than once every 2 days, and even more preferably more than once every 1 day.

[0060] The duration of addition of the oxidative slime inhibitor is not particularly limited. As a suitable lower limit, it is preferably 0.1 minutes or more, more preferably 1 minute or more, further preferably 10 minutes or more, and even more preferably 30 minutes or more. As a suitable upper limit, it is preferably 1000 minutes or less, more preferably 500 minutes or less, further preferably 300 minutes or less, and even more preferably 120 minutes or less. As a suitable numerical range, it is preferably 10 minutes or more and 300 minutes or less, more preferably 30 minutes or more and 120 minutes or less.

[0061] In this specification, the "period of addition of oxidative slime inhibitor" will also be referred to as the "period of addition of the first process" or the "period of addition of the first intermittent process".

[0062] In this specification, "the period of addition of oxidized slime inhibitor" refers to "the period of addition from the start of the addition of oxidized slime inhibitor to the end of the addition of oxidized slime inhibitor", more preferably it refers to "the period of continuous addition of oxidized slime inhibitor without impairing the effect of the present invention", and further, in a narrower sense, it refers to "the period of continuous addition without stopping the addition of oxidized slime inhibitor".

[0063] In this specification, the "1 period (specifically, the addition period from the start of the addition of the agent to the end of the addition of the agent)" in "addition period of oxidative slime inhibitor" may also be set to "1 unit".

[0064] In this specification, the "period during which no oxidized slime inhibitor is added" is also referred to as the "period other than the period during which oxidized slime inhibitor is added", the "period other than the period during which the first process is added", or the "period other than the period during which the first intermittent addition is added", and is also referred to as the "first no-addition period".

[0065] In this specification, "the period during which no oxidized slime inhibitor is added" refers to "the period from the end of the addition of the oxidized slime inhibitor to the start of the addition of the oxidized slime inhibitor (i.e., the period without addition)", more preferably, it refers to the period during which the oxidized slime inhibitor is added discontinuously without impairing the effects of the present invention, and more specifically, in a narrower sense, it refers to "the period during which the oxidized slime inhibitor is added discontinuously without any addition of the oxidized slime inhibitor".

[0066] In this specification, the "period without addition of oxidative slime inhibitor" may also be set as "1 unit".

[0067] There is no particular limitation on the concentration of the oxidative slime inhibitor added to the water system (mg / 1L of water system (based on total chlorine concentration)). As a suitable lower limit based on total chlorine concentration, it is preferably 0.1 mg / L or more (more preferably 0.5 mg / L or more), more preferably 1 mg / L or more, even more preferably 2 mg / L or more, even more preferably 5 mg / L or more, even more preferably 10 mg / L or more, even more preferably 25 mg / L or more or 30 mg / L or more. Furthermore, as a suitable upper limit, it is preferably 600 mg / L or less, more preferably 60 mg / L or less. As a suitable numerical range, it is preferably 0.1 mg / L to 600 mg / L, more preferably 2 mg / L to 60 mg / L.

[0068] As a suitable embodiment of the present invention, it is preferable that the concentration of the oxidative slime inhibitor is adjusted to be higher than that of the organic slime inhibitor described later. When the concentration of the organic slime inhibitor is set to 1 mg / L (based on reagent mass concentration), the concentration of the oxidative slime inhibitor (mg / L (based on total chlorine concentration)) is preferably 1 or more, more preferably 1.5 or more, more preferably 2 or more, more preferably 3 or more, and preferably 100 or less, more preferably 50 or less, more preferably 40 or less or 30 or less. As a suitable numerical range, when the concentration of the organic slime inhibitor is set to 1 mg / L (based on reagent mass concentration), the concentration of the oxidative slime inhibitor (mg / L (based on total chlorine concentration)) is preferably 2 to 50, more preferably 3 to 40.

[0069] The absolute amount (mg / (L / h)) of the oxidative slime inhibitor added to the water system during each addition period is not particularly limited, and can be calculated based on "the addition period of each unit of oxidative slime inhibitor × the addition concentration of the oxidative slime inhibitor at this time (mg / L (based on total chlorine concentration))". As a suitable lower limit value based on total chlorine concentration, it is preferably 0.05 mg / (L / h) or more, more preferably 0.1 mg / (L / h) or more, further preferably 0.5 mg / (L / h) or more, and further more preferably 1 mg / (L / h) or more. More preferably, the concentration is 2.5 mg / (L / h) or higher, more preferably 5 mg / (L / h) or higher, more preferably 10 mg / (L / h) or higher, more preferably 20 mg / (L / h) or higher, more preferably 25 mg / (L / h) or higher, more preferably 30 mg / (L / h) or higher. Furthermore, as a suitable upper limit, it is preferably 10000 mg / (L / h) or lower, more preferably 5000 mg / (L / h) or lower, more preferably 1000 mg / (L / h) or lower, and even more preferably 500 mg / (L / h) or lower. As a suitable numerical range, it is preferably 0.05 mg / (L / h) to 10000 mg / (L / h), more preferably 2.5 mg / (L / h) to 5000 mg / (L / h), and even more preferably 2.5 mg / (L / h) to 1000 mg / (L / h).

[0070] Furthermore, the first addition process involves intermittently adding oxidized slime inhibitors, which includes periods of adding oxidized slime inhibitors to the water system (hereinafter also referred to as "first intermittent addition period") and periods of not adding oxidized slime inhibitors (hereinafter also referred to as "first no-addition period"). These periods can preferably be performed sequentially or out of order. Preferably, they are performed sequentially. In this case, either the first intermittent addition period or the first no-addition period can be performed first, or either the first intermittent addition period followed by the first no-addition period, or the first no-addition period followed by the first intermittent addition period. Additionally, the number of each of the first intermittent addition period and the first no-addition period during the entire operation of the water system can be single or multiple.

[0071] The number of units during the first intermittent addition period is not particularly limited, and the structure described in the "Addition Period of Oxidized Slime Inhibitor" can be used as a suitable numerical range, preferably 1 minute to 1000 minutes, more preferably 10 minutes to 300 minutes.

[0072] The first unit of additive-free period is not particularly limited, but as a suitable lower limit, it is preferably 1 hour or more, more preferably 3 hours or more, more preferably 5 hours or more, and more preferably 10 hours or more. As a suitable upper limit, it is preferably 200 hours or less, more preferably 150 hours or less, more preferably 100 hours or less, and more preferably 50 hours or less. As a suitable numerical range, it is preferably 5 hours to 100 hours, and more preferably 10 hours to 50 hours.

[0073] The ratio of the first intermittent addition period to the first no-addition period in the total period of "one unit of the first intermittent addition period and one unit of the first no-addition period" is not particularly limited. However, from the viewpoint of reducing the dosage of additives used in the water system and ensuring the long-term stable operation of the water system, it is preferable that the first intermittent addition period is shorter than the first no-addition period. The ratio of the first intermittent addition period to the first no-addition period is preferably 1:2 to 500, more preferably 1:3 to 200, even more preferably 1:5 to 100, and even more preferably 1:7 to 50.

[0074] Furthermore, the first intermittent addition period for each unit can also be the average value obtained by dividing the total number of first intermittent addition periods (days, hours, etc.) in a certain operating period by the number of first intermittent addition periods in the operating period. Additionally, the first no-addition period for each unit can also be the average value obtained by dividing the total number of first no-addition periods (days, hours, etc.) in a certain operating period by the number of first no-addition periods in the operating period.

[0075] In addition, the operation period of the first addition process in this embodiment can be a single period of "a first intermittent addition period and a first no-addition period per unit", or it can be a period composed of multiple identical or different "first intermittent addition periods and first no-addition periods per unit".

[0076] <Oxidative Slime Inhibitor>

[0077] There are no particular limitations on the oxidative slime inhibitor or its components. For example, halogenated compounds can be listed. The oxidative slime inhibitor may be an agent containing halogenated compounds. Halogens can be listed as chlorine, bromine, etc.

[0078] Examples of halogenated compounds include chlorinated compounds and bromine compounds, and one or more of these compounds may be used.

[0079] Examples of the bound chlorine compounds include, for example, stabilized chlorine compounds such as halogenated hydantoin compounds, chloramine compounds, etc.; examples of the bound bromine compounds include, for example, stabilized bromides, halogenated hydantoin compounds, etc., but are not limited to these, and one or more selected from these may be used. The compounds used in oxidative slime inhibitors or oxidative slime inhibitors may be commercially available products or those obtained using known manufacturing methods.

[0080] Furthermore, there are no particular limitations on the salts of chloramine compounds, salts of stabilized bromides, and other halogenated compounds. Examples include: alkali metal salts such as sodium and potassium salts; alkaline earth metal salts such as calcium, strontium, and barium salts; other metal salts such as manganese, copper, zinc, iron, cobalt, and nickel salts; ammonium salts and organic ammonium salts; and amino acid salts such as guanidine salts. One or more of these can be used.

[0081] <Chloramine compounds>

[0082] Chloramine compounds are compounds that have at least one bond between a nitrogen atom and a chlorine atom (N-Cl bond).

[0083] Examples of chloramine compounds include chloramines, chloramine sulfonic acid compounds, and other chloramine compounds. One or more of these compounds may be used.

[0084] Examples of chloramine compounds include: stabilized chlorine compounds formed from substances containing stabilizers and chlorine oxides; and chloramine sulfonic acid compounds formed from substances containing amine sulfonic acid compounds and chlorine oxides. One or more of these compounds may be used.

[0085] As a stabilizer, there are no particular limitations on the type of substance that can generate a bound halogen (preferably a stabilized bound halogen), but compounds containing an amino group, such as ammonium salts and amine sulfonic acid compounds, are preferred. One or more of these can be used. Furthermore, in this specification, a monovalent functional group (-NH2, -NHR, -NRR') formed by removing hydrogen from ammonia, a primary amine, or a secondary amine is referred to as an "amino group".

[0086] Examples of ammonium salts include ammonium sulfate, ammonium nitrate, and ammonium chloride, and one or more of these can be used. Among these, ammonium sulfate is preferred.

[0087] The amine sulfonic acid compounds that constitute chloramine sulfonic acid compounds are preferably composed of R 1 R 2 The compound represented by NSO3H…[1]. Suitable is R in the general formula [1]. 1 R 2Each is independently H or an alkyl group having 1 to 8 carbon atoms or a functional group containing a benzene ring.

[0088] As amine sulfonic acid compounds, examples include: two R 1 Base and R 2 Aminosulfonic acids (amide sulfuric acid) or their salts, where both radicals are hydrogen atoms; N-methylamine sulfonic acid, N-ethylamine sulfonic acid, N-propylamine sulfonic acid, N-isopropylamine sulfonic acid, N-butylamine sulfonic acid, etc., with two R radicals. 1 Base and R 2 Aminosulfonic acids or their salts in which one of the radicals is a hydrogen atom and the other is an alkyl group having 1 to 8 carbon atoms; N,N-dimethylaminesulfonic acid, N,N-diethylaminesulfonic acid, N,N-dipropylaminesulfonic acid, N,N-dibutylaminesulfonic acid, N-methyl-N-ethylaminesulfonic acid, N-methyl-N-propylaminesulfonic acid, etc., where two Rs are present. 1 Base and R 2 The groups are alkyl groups having 1 to 8 carbon atoms, such as aminosulfonic acids or their salts, but are not limited to these. One or more of these groups may be used.

[0089] There are no particular limitations on the chlorine oxides mentioned above. Examples include chlorine gas, chlorine dioxide, hypochlorous acid or its salts, chlorite or its salts, chloric acid or its salts, perchloric acid or its salts, chloroisocyanuric acid or its salts, etc. One or more of these may be used.

[0090] Examples of hypochlorites include sodium hypochlorite, potassium hypochlorite, and other alkali metal hypochlorite salts; calcium hypochlorite, barium hypochlorite, and other alkaline earth metal hypochlorite salts; and one or more of these may be used.

[0091] Examples of chlorites include: sodium chlorite, potassium chlorite, and other alkali metal salts of chlorites; barium chlorite and other alkaline earth metal salts of chlorites; nickel chlorite and other metal salts of chlorites. One or more of these can be used.

[0092] Examples of chlorates include: ammonium chlorate; sodium chlorate, potassium chlorate and other alkali metal chlorate salts; calcium chlorate, barium chlorate and other alkaline earth metal chlorate salts, etc., and one or more of these may be used.

[0093] As perchlorates, examples include sodium perchlorate and potassium perchlorate, and one or more of these may be used.

[0094] As a chloroisocyanurate, such as sodium chloroisocyanurate, one or more of these may be used.

[0095] As an example of manufacturing chloramine compounds, a method can be cited where an aqueous solution of a stabilizer (e.g., an aqueous solution of an ammonium sulfonic acid compound) and an aqueous solution of a chlorine oxide (e.g., an aqueous solution of sodium hypochlorite) are mixed in the presence of an alkaline environment. The chloramine compound can be generated at least by the stabilizer and the chlorine oxide. The pH value of the pharmaceutical preparation containing the manufactured chloramine compound is preferably 12 or higher, more preferably 13 or higher.

[0096] For example, as an example of manufacturing sodium chloramine sulfonate, the method described in the [Example] of Patent Document 3 (WO 2011 / 125762; Japanese Patent 5720964) can be referred to.

[0097] The ratio of chlorine oxides to stabilizers (e.g., ammonium salts, amine sulfonic acid compounds, etc.) is not particularly limited. However, relative to 1 mole of the total chlorine concentration (Cl2) of the chlorine oxidant, the concentration of the chlorine stabilizer (preferably an amine sulfonic acid compound) is preferably set to 0.5 mol to 5.0 mol, more preferably 0.5 mol to 2.0 mol, and even more preferably 1.0 mol to 1.5 mol. The ratio can also be the proportion contained in the reagent.

[0098] The ratio of alkali to chlorine oxides used is preferably 0.3 to 0.4, more preferably 0.30 to 0.36, based on the Cl / alkali metal (molar ratio). The ratio can also be the proportion contained in the reagent.

[0099] As an aminosulfonic acid compound, R is more preferably preferred. 1 R 2 The narrow definition of amine sulfonic acid (H) can also be used, including N-methylamine sulfonic acid, N,N-dimethylamine sulfonic acid, N-phenylamine sulfonic acid, chloramine T, etc. Regarding amine sulfonic acid compounds, these amine sulfonic acids can be used in their free (powdered) acidic state, or as alkali metal salts such as sodium salts, potassium salts, and lithium salts. One or more of these can be used.

[0100] Chloramine sulfonic acid refers to chloramine sulfonic acid formed by substituting at least one hydrogen atom in the NH2 group of amine sulfonic acid (H2NSO2OH) with a chlorine atom. Examples of chloramine sulfonic acids include monochloramine sulfonic acid and dichloramine sulfonic acid.

[0101] Chloramine sulfonate refers to chloramine sulfonate formed by replacing at least one hydrogen atom in the OH group of ammonium sulfonic acid (H2NSO2OH) with a metal ion (e.g., alkali metal ions such as lithium ion, sodium ion, potassium ion, etc.).

[0102] Examples of chloramine sulfonates include lithium chloramine sulfonate, sodium chloramine sulfonate, and potassium chloramine sulfonate, and one or more of these may be used. Among these, sodium chloramine sulfonate is preferred.

[0103] Alternatively, chloramine T and other chloramine compounds may be used. Furthermore, one or more of these compounds may be used.

[0104] <Stabilized bromide>

[0105] A stabilized bromide is a compound having at least one bond between a nitrogen atom and a chlorine atom (N-Cl bond) or a bond between a carbon atom and a bromine atom (C-Br bond). A suitable stabilized bromide is one that is unlikely to undergo changes in water due to decomposition or other processes, and whose resulting bromide can exist stably in water.

[0106] Examples of stabilizing bromides include, but are not limited to, the reaction products of "bromine-based oxidants or bromine compounds with chlorine-based oxides" and "amine sulfonic acid compounds". Regarding the pH value of the reaction products, a base is preferred, more preferably 11 or higher, even more preferably 12 or higher, and even more preferably 13 or higher. These can be commercially available products or stabilized bromides obtained using known manufacturing methods.

[0107] There are no particular limitations on the bromine-based oxidizing agents. Examples include bromine (liquid bromine), bromine chloride, bromic acid, bromate, and hypobromic acid. One or more of these can be used.

[0108] There are no particular limitations on the bromine compounds used. Examples include sodium bromide, potassium bromide, lithium bromide and other alkali metal bromides, ammonium bromide and other bromides, and hydrobromic acid. One or more of these can be used.

[0109] Regarding the chlorine oxides (e.g., hypochlorite, chlorite, chlorate, perchlorate, isocyanurate chloride, etc.) used in stabilizing bromides, the description of "chlorine oxides" in the <chloramine compound> applies to these, and the structures described herein are suitable. Among these, hypochlorite (e.g., sodium hypochlorite) is preferred.

[0110] Regarding "amine sulfonic acid compounds," the "amine sulfonic acid compounds constituting chloramine sulfonic acid compounds are composed of R..." 1 R 2 The description of "amine sulfonic acid compounds" in "compounds represented by NSO3H…[1]" applies to these, and the structures described therein may be used appropriately. Among "amine sulfonic acid compounds", amine sulfonic acid or its salt is preferred.

[0111] As an example of manufacturing stabilized bromides, the following method can be used: mixing an aqueous solution of sodium bromide with sodium hypochlorite to prepare a mixed solution 1, and on the other hand, mixing an aqueous solution of ammonium sulfonic acid with an aqueous solution of sodium hydroxide to prepare a mixed solution 2, and mixing the mixed solution 1 and the mixed solution 2 in the presence of an alkali.

[0112] For example, bromamine or bromamine sulfonic acid containing ammonium salt and bromine, as well as bromamine sulfonate, and DBNPA as other compounds can be used.

[0113] <Halogenated hydantoin compounds>

[0114] Examples of halogenated hydantoin compounds include, for example, 1-bromo-3-chloro-5,5-dimethylhydantoin (also known as "BCDMH"), 1,3-dichloro-5,5-dimethylhydantoin, 1,3-dibromo-5,5-dimethylhydantoin, 1-bromo-3-chloro-5,5-diethylhydantoin, 1,3-dichloro-5,5-diethylhydantoin, and 1-bromo-3-chloro-5-methyl-5-ethylhydantoin, and one or more of these can be used. Among these, BCDMH and 1,3-dichloro-5,5-dimethylhydantoin are preferred from the viewpoint of balancing the dissolution rate with the solidifying agent (B) upon contact with water or from the viewpoint of ease of acquisition.

[0115] Halogenated hydantoin compounds are commercially available and can also be obtained using known manufacturing methods, for example, by reacting a hydantoin compound (e.g., hydantoin (chemical formula: C3H4N2O2) etc.) as a stabilizer with the chlorine oxide and / or bromine oxidant. Examples of hydantoin compounds include compounds having a hydantoin skeleton, such as hydantoin, 5,5-dialkylhydantoin (e.g., 5,5-dimethylhydantoin, 5-methylethylhydantoin, 5-methylbutylhydantoin, and 5-ethylbutylhydantoin, etc.), and one or more selected from these may be used. The "dialkyl" may be the same or different alkyl groups. Examples of alkyl groups include those with 1 to 5 carbon atoms (preferably 1 to 3 carbon atoms). In addition, it may be linear or branched, for example, methyl, ethyl, butyl, etc., and one or more of these may be used.

[0116] Furthermore, without impairing the effects of the present invention, the oxidative slime inhibitor may suitably contain any component or agent. Examples of such components or agents include: corrosion inhibitors, scale inhibitors, slime control agents, solvents or dispersion media such as water, dispersants, enzymes, bactericides, and defoamers, etc., but are not limited thereto. Additionally, various agents commonly used in water treatment may also be used. One or more of these components or agents may be suitably selected.

[0117] In addition, in the first step of this embodiment, any ingredient or agent may be added or used independently of the addition or use of the oxidative slime inhibitor.

[0118] 1-1-2. First Supply Process

[0119] The first supply step is suitable for intermittently supplying treated water containing oxidative slime inhibitors to the reverse osmosis membrane unit. By combining the first supply step with the second supply step described below, the water system can operate for a longer period of time. More preferably, biological fouling generated in the reverse osmosis membrane included in the reverse osmosis membrane unit can be suppressed, thereby enabling the water system to operate stably for a long period.

[0120] In the first supply process, when the treated water containing the oxidized slime inhibitor is intermittently supplied to the reverse osmosis membrane device, there is a period during which the treated water containing the oxidized slime inhibitor is supplied (also referred to as the "first intermittent supply period") and a period during which the treated water containing the oxidized slime inhibitor is not supplied (also referred to as the "first no-supply period").

[0121] The various conditions in the first supply process can be appropriately described using the structure of the "1-1-1. First Addition Process" description.

[0122] For example, the supply frequency and its specified period, supply times, supply frequency, supply period, supply concentration of oxidized slime inhibitor for the water system, absolute amount of oxidized slime inhibitor supplied to the water system in each supply period, 1 unit of the first supply period, and the period ratio of each unit of the first intermittent supply period to each unit of the first no-supply period in the first supply process can be appropriately adopted from the addition frequency and its specified period, addition times, addition frequency, addition period, addition concentration of oxidized slime inhibitor for the water system, absolute amount of oxidized slime inhibitor added to the water system in each addition period, 1 unit of the first addition period, and the period ratio of each unit of the first intermittent addition period to each unit of the first no-addition period in the first supply process.

[0123] There is no particular limitation on the supply frequency of the treated water containing the oxidative slime inhibitor, but it is preferable to supply it more than once within a specified period, and more preferably once. The supply frequency can be "within a specified period" or "every specified interval".

[0124] There is no particular limitation on the frequency of supplying the oxidative slime inhibitor, but a suitable upper limit is more preferably two times or less, and even more preferably once. Regarding the supply frequency of the treated water containing the oxidative slime inhibitor, it is preferable to supply it at least once every three days, more preferably at least once every two days (more preferably every other day), and even more preferably once or more once a day. Furthermore, the frequency of supply can be "within a specified period" or "at every specified interval."

[0125] In terms of the supply frequency of oxidative slime inhibitors, it is preferable to supply them more than once every 3 days, and more preferably more preferably to supply them more than once a day.

[0126] The supply period of the treated water containing the oxidative slime inhibitor is not particularly limited, but a suitable numerical range is 10 minutes or more and 300 minutes or less, more preferably 30 minutes or more and 120 minutes or less, per cycle (1 period).

[0127] In this specification, "the supply period of the treated water containing the oxidized slime inhibitor" means "the supply period from the start of the supply of the oxidized slime inhibitor to the end of the supply of the oxidized slime inhibitor", and more specifically, "the period during which the supply of the oxidized slime inhibitor is continuous without stopping the supply".

[0128] In addition, in this specification, the "supply period of the treated water containing the oxidative slime inhibitor" will also be referred to as the "supply period of the first process" or the "first intermittent supply period".

[0129] Alternatively, in this specification, the "1 period (specifically, the supply period from the start of the supply of the agent to the end of the supply of the agent)" in the "supply period of the treated water containing the oxidative slime inhibitor" may be set as "1 unit".

[0130] In this specification, "the period during which the treated water containing oxidized slime inhibitor is not supplied" is also referred to as "the period other than the period during which the treated water containing oxidized slime inhibitor is supplied", "the period other than the period during which the first process is supplied", or "the period other than the period during which the first intermittent supply is supplied", and is also referred to as "the first no-supply period".

[0131] In this specification, "the period during which the treated water containing the oxidized slime inhibitor is not supplied" means "the period of no supply from the end of the supply of the oxidized slime inhibitor to the start of the supply of the oxidized slime inhibitor", and more specifically, "the period during which the oxidized slime inhibitor is not supplied to the reverse osmosis membrane unit and is not supplied intermittently".

[0132] In this specification, the "period of not supplying the treated water containing the oxidizing slime inhibitor" may also be defined as "1 unit".

[0133] There is no particular limitation on the supply concentration of the oxidative slime inhibitor for the water system (mg of agent per 1L of water system). As a suitable lower limit value based on the total chlorine concentration, it is preferably 0.1 mg / L or more (more preferably 0.5 mg / L or more), more preferably 1 mg / L or more, even more preferably 2 mg / L or more, even more preferably 5 mg / L or more, even more preferably 10 mg / L or more, even more preferably 25 mg / L or more. In addition, as a suitable numerical range, it is preferably 5 mg / L to 500 mg / L, more preferably 25 mg / L to 300 mg / L.

[0134] The absolute amount (mg × hour) of oxidative slime inhibitor supplied to the reverse osmosis membrane unit per supply period is not particularly limited, and can be calculated based on "the supply period of each unit of treated water containing oxidative slime inhibitor × the supply concentration of oxidative slime inhibitor at that time". As a suitable lower limit value, it is preferably 0.05 mg / (L / h) or more, more preferably 0.1 mg / (L / h) or more, and even more preferably 0.5 mg / (L / h) or more. More preferably, it is 1 mg / (L / h) or more, more preferably 2.5 mg / (L / h) or more, more preferably 10 mg / (L / h) or more, and even more preferably 25 mg / (L / h) or more. In addition, as a suitable numerical range, it is preferably 0.05 mg / (L / h) to 10000 mg / (L / h), more preferably 2.5 mg / (L / h) to 5000 mg / (L / h), and even more preferably 10 mg / (L / h) to 1000 mg / (L / h).

[0135] Furthermore, the first supply process, by supplying treated water containing oxidized slime inhibitors to the reverse osmosis membrane unit, includes periods during which the treated water containing oxidized slime inhibitors is supplied to the reverse osmosis membrane unit (hereinafter also referred to as "first intermittent supply period") and periods during which the treated water containing oxidized slime inhibitors is not supplied to the reverse osmosis membrane unit (hereinafter also referred to as "first no-supply period"). These periods are preferably performed sequentially or out of order. Sequential performance is preferred. The order of these first intermittent supply periods and first no-supply periods is preferably based on the order of the first intermittent addition period and the first no-addition period. Additionally, the number of each of the first intermittent supply period and the first no-supply period during the entire operation of the water system can be single or multiple.

[0136] There is no particular limitation on the unit of the first intermittent supply period. As a suitable numerical range, it is preferably 1 minute to 1000 minutes, and more preferably 10 minutes to 300 minutes.

[0137] There is no particular limitation on the first unit during the period of no supply. As a suitable numerical range, it is preferably 5 hours to 100 hours, and more preferably 10 hours to 50 hours.

[0138] The ratio of the first intermittent supply period to the first no-supply period in the total period of "one unit of the first intermittent supply period and one unit of the first no-supply period" is not particularly limited. It is suitable that the first intermittent supply period is shorter than the first no-supply period, and more preferably 1:7 to 50.

[0139] Furthermore, the first intermittent supply period for each unit can also be the average value obtained by dividing the total number of first intermittent supply periods (days, etc.) in a certain operating period by the number of first intermittent supply periods in the operating period. Additionally, the first no-supply period for each unit can also be the average value obtained by dividing the total number of first no-supply periods (days, etc.) in a certain operating period by the number of first no-supply periods in the operating period.

[0140] Furthermore, the operation period of the first supply process in this embodiment can be a single period consisting of "a first intermittent supply period and a first no-supply period per unit", or it can be a period consisting of multiple combinations of the same or different "first intermittent supply periods and first no-supply periods per unit". The single period or multiple combinations of periods are preferably based on the single period or multiple combinations of the "first intermittent addition period and first no-addition period per unit".

[0141] 1-2. The second step using organic slime inhibitors

[0142] The second step is suitable to add an organic slime inhibitor during a period other than at least the addition period of the first step, and to supply the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0143] Furthermore, the second process is suitable to include: a second addition process for adding an organic slime inhibitor; and a second supply process for supplying the treated water containing the added organic slime inhibitor to the reverse osmosis membrane unit.

[0144] 1-2-1. Second Addition Process

[0145] The second addition step is the addition of an organic slime inhibitor during at least a period other than the addition period of the first step. This yields treated water containing the organic slime inhibitor, which can then be supplied to a reverse osmosis membrane unit (e.g., see reference). Figure 1 and Figure 2 ).

[0146] The second addition step is suitable for adding an organic slime inhibitor at least during a period other than the addition period of the first step.

[0147] Here, the phrase "adding during at least a period other than the addition period of the first step" in the second addition process, also known as "adding organic slime inhibitor during at least the first no-addition period," can refer to adding organic slime inhibitors during both the first no-addition period and the first intermittent addition period, or adding organic slime inhibitors only during the first no-addition period (e.g., see reference). Figure 1 and Figure 2 ).

[0148] In the second addition step, the addition of organic slime inhibitors during the first additive-free period can also be the addition of organic slime inhibitors during the entire or part of the first additive-free period.

[0149] In addition, in the second addition step, the addition of organic slime inhibitor during the first intermittent addition period can be the addition of organic slime inhibitor during the entire period or a part of the first intermittent addition period.

[0150] Furthermore, in the second addition step, it is preferable to add an organic slime inhibitor during the entire or a portion of the first additive-free period, specifically during the entire first additive-free period. Moreover, the portion of the first additive-free period is preferably 50% or more, more preferably 70% or more, further preferably 90% or more, even more preferably 95% or more, even more preferably 98% or more, even more preferably 99% or more, and even more preferably 100% (also referred to as the entire period) relative to the entire first additive-free period.

[0151] In the second addition step, it is more preferable to add the organic slime inhibitor continuously or intermittently during "a period other than the addition period of at least the first step", and more preferably to add it continuously, and even more preferably to add it continuously.

[0152] Furthermore, in the second addition step, it is more preferable to add the organic slime inhibitor continuously or intermittently during at least "each unit of the first no-addition period", and more preferably to add it continuously.

[0153] In this specification, the term "discontinuous" can refer to a period of adding organic slime inhibitor and a period of stopping, provided that the effect of the invention is not impaired. Preferably, the period of addition is longer than the period of stopping, and the period of stopping is preferably within 1 / 10 of the period of addition, more preferably within 5 / 100, and even more preferably within 2.5 / 100, and even more preferably within 1 / 500.

[0154] In this specification, the term "continuous" addition period of the organic slime inhibitor refers to "the addition period from the start of the addition of the organic slime inhibitor to the end of the addition of the organic slime inhibitor," more preferably, it refers to "the period during which the organic slime inhibitor is continuously added without impairing the effects of the present invention," and further, in a narrower sense, it refers to "the period during which the addition of the organic slime inhibitor is continuously carried out without stopping," also referred to as "the period of continuous addition." For example, the "period of continuous addition" can be exemplified as "0 minutes of no addition and 60 minutes of addition" relative to a 60-minute operating period.

[0155] In this specification, the term "continuously" refers to a period during which the medication is stopped if the effect is the same as that of continuous addition according to the present invention. As a more specific and suitable form, the period during which the medication is stopped within one day is preferably 60 minutes or less, more preferably 30 minutes or less, even more preferably 15 minutes or less, even more preferably 5 minutes or less, and even more preferably 0 minutes (also referred to as "the period of continuous addition"). Furthermore, the period during which the medication is stopped within one hour of operation is preferably 5 minutes or less, more preferably 1 minute or less, even more preferably 5 minutes or less, and even more preferably 0 minutes (also referred to as "the period of continuous addition").

[0156] There is no particular limitation on the addition period of the organic slime inhibitor. For example, the entire operation period of the reverse osmosis membrane unit or the entire period of the first process can be defined as the addition period of the organic slime inhibitor. More specifically, per instance (1 period), the suitable lower limit is preferably 0.1 days or more, more preferably 0.3 days or more, more preferably 0.5 days or more, more preferably 1 day or more. In addition, the suitable upper limit is preferably 30 days or less, more preferably 10 days or less, more preferably 7 days or less, more preferably 3 days or less. As for the suitable numerical range, it is preferably 0.5 days or more and 7 days or less, more preferably 1 day or more and 3 days or less.

[0157] There is no particular limitation on the concentration (mg (based on reagent mass) / 1L of water system) of the organic slime inhibitor added to the water system. As a suitable lower limit value based on reagent mass concentration, it is preferably 0.001 mg / L or more, more preferably 0.01 mg / L or more, further preferably 0.05 mg / L or more, and further preferably 0.1 mg / L or more. As a suitable upper limit value, it is preferably 10000 mg / L or less, more preferably 1000 mg / L or less, further preferably 100 mg / L or less, and further preferably 50 mg / L or less. As a suitable numerical range, it is preferably 0.01 mg / L to 100 mg / L, more preferably 0.1 mg / L to 50 mg / L.

[0158] The absolute amount (mg (based on the mass of the agent) of the organic slime inhibitor added to the water system during each addition period is not particularly limited, and can be calculated by "the addition period of the organic slime inhibitor × the addition concentration of the organic slime inhibitor at this time". As a suitable lower limit, it is preferably 0.002 mg / (L / h) or more, more preferably 0.02 mg / (L / h) or more, more preferably 0.2 mg / (L / h) or more, more preferably 2 mg / (L / h) or more. As a suitable upper limit, it is preferably 6,000,000 mg / (L / h) or less, more preferably 300,000 mg / (L / h) or less, more preferably 30,000 mg / (L / h) or less, more preferably 3,000 mg / (L / h) or less. The preferred numerical range is 0.2 mg / (L / h) to 30000 mg / (L / h), and more preferably 2 mg / (L / h) to 3000 mg / (L / h).

[0159] <Organic Slime Inhibitor>

[0160] The organic slime inhibitor or its components are not particularly limited, and examples include isothiazolinone compounds, halocyanoacetamide compounds, aldehyde compounds, and oxime compounds represented by tetrazolium oxime or dichloroglyoxime, etc., and one or more of these compounds may be used. Alternatively, the organic slime inhibitor may also be a pharmaceutical agent containing one or more of these compounds. The organic slime inhibitor or the compounds used in the organic slime inhibitor may be commercially available products or those obtained using known manufacturing methods.

[0161] <Isothiazolin compounds>

[0162] There are no particular limitations on the isothiazolinones used, and examples include: 5-chloro-2-methyl-4-isothiazoline-3-one (Cl-MIT), 2-methyl-4-isothiazoline-3-one (MIT), 2-ethyl-4-isothiazoline-3-one, 2-n-octyl-4-isothiazoline-3-one, 5-chloro-2-ethyl-4-isothiazoline-3-one, 5-chloro-2-tert-octyl-4-isothiazoline-3-one, 4,5-dichloro-2-n-octyl-4-isothiazoline-3-one, 4,5-dichloro-2-cyclohexyl-4-isothiazoline-3-one, etc., and one or more of these compounds may be used. Alternatively, complexes of the isothiazolinate compound with magnesium chloride, magnesium nitrate, copper chloride, copper nitrate, calcium chloride, etc., may also be used as isothiazolinate compounds. One or more of these compounds may be used.

[0163] Among the isothiazolino compounds, 5-chloro-2-methyl-4-isothiazolin-3-one (Cl-MIT), 2-methyl-4-isothiazolin-3-one (MIT), or mixtures thereof are preferred.

[0164] <Halogenated cyanoacetamide compounds>

[0165] There are no particular limitations on the halogenated cyanoacetamide compound. Examples include: 2-chloro-3-azoxypropionamide, 2-bromo-3-azoxypropionamide, and other 2-halogenated-3-azoxypropionamides; 2,2-dichloro-3-azoxypropionamide, 2,2-dibromo-3-azoxypropionamide (DBNPA), 2-chloro-2-bromo-3-azoxypropionamide, and other 2,2-dihalogenated-3-azoxypropionamides; N-methyl-2-chloro-3-azoxypropionamide, N-methyl-2-bromo-3-azoxypropionamide, and other N-C1-3 alkyl-2-halogenated-3-azoxypropionamides; N-methyl-2,2-dichloro-3-azoxypropionamide, N-methyl-2,2-dibromo-3-azoxypropionamide, and other N-C1-3 alkyl-2,2-dihalogenated-3-azoxypropionamides, etc. One or more of these compounds may be used.

[0166] Furthermore, halogenated cyanoacetamide compounds can also be derived from NC-CX. 1 X 2 -(C=O)-NHR 3 …[2] represents the compound. In the general formula [2], X 1 X 2 Each can independently represent a halogen atom or a hydrogen atom, X 1 X 2 At least one of them is a halogen atom. R 3 It represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of halogen atoms include chlorine and bromine, with bromine being preferred. As a C1-3 alkyl group, it can be either straight-chain or branched-chain, for example, methyl, ethyl, n-propyl, isopropyl, etc. One or more of these can be used.

[0167] Among the halocyanoacetamide compounds, dihalo-nitropropionamides are preferred, and among these, 2,2-dibromo-3-nitropropionamide (DBNPA) is even more preferred.

[0168] Aldehyde compounds

[0169] There are no particular limitations on aldehyde compounds. Examples include monoaldehyde compounds such as acetaldehyde and dialdehyde compounds such as glyoxal and ortho-phthalaldehyde. One or more of these compounds may be used.

[0170] Among aldehyde compounds, dialdehyde compounds are preferred, and among dialdehyde compounds, glutaraldehyde is preferred from the viewpoint of high safety.

[0171] <Oxime Compounds>

[0172] The oxime compound is not particularly limited, and examples include oxime compounds having a tetrazolium ring (CH2N4) (e.g., tetrazolyl oximes), and halooxime compounds (e.g., dichloroglyoximes), etc., and one or more of these may be used. The oxime compound is a compound having a structure represented by >C=N-OH within its molecule.

[0173] Examples of oxime compounds containing a tetrazolium ring include: picarbutrazox (molecular formula: C2). 20 H 23 N7O3 (molecular weight: 409.44, CAS No. 500207-04-5), etc.

[0174] Examples of halooxime compounds include dichloroglyoxime, α-chlorobenzaldehyde oxime, α-chlorobenzaldehyde oxime acetate, and 4-hydroxyphenyl-α-one acetylhydroxamic acid chloride (also known as PARACLOX). One or more of these compounds may be used.

[0175] Among organic slime inhibitors, one or more of the following are preferred: 2,2-dibromo-3-azoxypropionamide (DBNPA), 5-chloro-2-methyl-4-isothiazolin-3-one (Cl-MIT), and 2-methyl-4-isothiazolin-3-one (MIT), or mixtures thereof, glutaraldehyde, etc.

[0176] Furthermore, without impairing the effects of the present invention, the organic slime inhibitor may suitably contain any component or agent. Additionally, in the second step of this embodiment, any component or agent may be added or used independently of the addition or use of the organic slime inhibitor. The arbitrary component or agent may be any agent commonly used in water treatment, and the structure described in the description of "arbitrary component or agent" for the <oxidative slime inhibitor> may be suitable.

[0177] 1-2-2. Second supply process

[0178] The second supply step is suitable for supplying treated water containing organic slime inhibitors to the reverse osmosis membrane unit. By combining the second supply step with the first supply step in the first step, the water system can operate for a longer period of time. More preferably, biological fouling generated in the reverse osmosis membrane included in the reverse osmosis membrane unit can be suppressed, thereby enabling the water system to operate stably for a long period.

[0179] The various conditions in the second supply process can be appropriately described using the structure of the "1-2-1. Second Addition Process" description.

[0180] For example, the supply period in the second supply process, the supply concentration of the organic slime inhibitor for the water system, and the absolute amount of the organic slime inhibitor supplied to the water system in each supply period can be appropriately adopted from the addition period, the addition concentration of the organic slime inhibitor for the water system, and the absolute amount of the organic slime inhibitor added to the water system in each addition period of the "1-2-1. Second Addition Process".

[0181] In the second supply step, it is suitable to supply the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit during a period other than the supply period of at least the first step. The treated water containing the organic slime inhibitor is preferably supplied to the reverse osmosis membrane unit continuously or intermittently during operation, more preferably continuously, and even more preferably continuously.

[0182] In this specification, the term "continuous" supply period of the organic slime inhibitor refers to "the supply period from the start of the supply of the organic slime inhibitor to the end of the supply of the organic slime inhibitor," and more specifically, in a narrower sense, it refers to "the period of continuous supply without stopping the supply of the organic slime inhibitor," which is defined as "the period of continuous supply."

[0183] There is no particular limitation on the supply period of the organic slime inhibitor. The entire operation period of the reverse osmosis membrane unit or the entire period of the first process can be defined as the supply period of the organic slime inhibitor. More specifically, the suitable numerical range is preferably 0.5 days or more and 7 days or less, more preferably 1 day or more and 3 days or less, per cycle (1 period).

[0184] There is no particular limitation on the supply concentration (mg / 1L of water system (based on reagent mass concentration)) of the organic slime inhibitor for the reverse osmosis membrane device. As a suitable numerical range, it is preferably 0.01 mg / L to 100 mg / L, and more preferably 0.1 mg / L to 50 mg / L.

[0185] The absolute amount (mg) of the organic slime inhibitor supplied to the reverse osmosis membrane unit during each supply period is not particularly limited. As a suitable numerical range, it is preferably 0.2 mg / (L / h) to 30000 mg / (L / h), and more preferably 2 mg / (L / h) to 3000 mg / (L / h).

[0186] 1-3. Control of the first and second processes in this embodiment

[0187] In the method of this embodiment, it is suitable to control the first and second processes, thereby enabling the water system with the reverse osmosis membrane device to operate for a longer period of time.

[0188] In this embodiment, a more suitable approach is to control the first and second addition steps. This allows for a better supply of treated water, containing oxidative and / or organic slime inhibitors, to the reverse osmosis membrane unit, thereby enabling the water system equipped with the reverse osmosis membrane unit to operate stably for a longer period. Furthermore, by controlling the first and second addition steps, the reduction of slime present in the reverse osmosis membrane or the suppression of slime accumulation can be improved, thereby also better inhibiting biological fouling.

[0189] In the method of this embodiment, the first step and the second step can be performed at the same time or at different times, but it is more suitable to perform them at the same time.

[0190] Furthermore, in the method of this embodiment, the first step and the second step can be performed in parallel or in sequence, and it is preferable to perform them in parallel.

[0191] In the method of this embodiment, as a more suitable form, it is more suitable to perform the first process and the second process in the same period and in parallel.

[0192] Furthermore, in the method of this embodiment, during the period when the oxidative slime inhibitor of the first step is added (preferably during the period of continuous addition), the organic slime inhibitor of the second step may be added, or the addition may be stopped. Furthermore, during the period when the oxidative slime inhibitor of the first step is not added, it is preferable to continuously add the organic slime inhibitor of the second step.

[0193] In the method of this embodiment, as a more suitable form, it is more suitable to control the first process and / or the second process based on the operating starting point of the first process and / or the second process, and the operating starting points may be the same or different.

[0194] There are no particular limitations on the starting point of operation, and it can be set arbitrarily. For example, the date (year, month, day, hour, minute, second) and the operation status of the first and / or second processes can be listed (e.g., when operation starts, when operation restarts, when medicine is added, any period setting, etc.). One or more combinations selected from these can be used.

[0195] As a more specific and suitable form of the starting point for operation, for example, the starting point could be the beginning of the first intermittent addition or the beginning of the first no-addition period in the first process, or a point within the second addition period of the second process, or the beginning of the first intermittent addition or the beginning of the first no-addition period in the second process. Furthermore, if both the first and second processes are in a no-addition period (e.g., both processes are stopped for maintenance, adjustment of the addition sequence, etc.), the starting point could be the beginning of the addition of the agent in at least one of the first and second processes (when addition resumes), or the starting point could be the simultaneous addition of the agent in both the first and second processes.

[0196] Reference Figure 1 and Figure 2 The control of the first addition process and the second addition process in this embodiment will be described, but this embodiment is not limited thereto.

[0197] Figure 1 This is a schematic diagram illustrating Example 1, showing the control of the first and second addition steps according to an embodiment of the present invention. Example 1 a1: In the first addition step, oxidized slime inhibitors are added intermittently at equal intervals. Example 1 b1: In the second addition step, organic slime inhibitors are continuously added. In this case, the organic slime inhibitor is added during periods other than the addition period of the first addition step. The horizontal axis represents the operating period (hours), and the vertical axis represents the addition amount. Furthermore, the operating period 0h of the first addition step and the operating period 0h of the second addition step can each be set as the operating start point. Moreover, the intermittent addition periods of the first addition step can be the same or different periods, and the intermittent addition amounts can be the same or different amounts. Additionally, the intervals between intermittent additions can be the same or different intervals.

[0198] According to Example 1 of the control in this embodiment, treated water containing oxidative slime inhibitors and / or organic slime inhibitors can be produced. Furthermore, according to Example 1 of the control in this embodiment, the treated water containing oxidative slime inhibitors and / or organic slime inhibitors is supplied to the reverse osmosis membrane unit in the form of a first supply step and a second supply step. At this time, it can be controlled by... Figure 1 In the same manner as shown in the addition patterns a1 and b1, treated water containing oxidative slime inhibitors and / or organic slime inhibitors is supplied to the reverse osmosis membrane unit. As a more specific example, treated water is supplied to the reverse osmosis membrane unit in the following order: treated water containing only organic slime inhibitors, treated water containing both oxidative and organic slime inhibitors…

[0199] This allows water systems equipped with reverse osmosis membrane devices to operate more stably over longer periods. It also improves the reduction of slime within the reverse osmosis membrane and better inhibits the increase of slime, thereby better suppressing biological fouling.

[0200] Figure 2 This is a schematic diagram illustrating Example 2, which shows the control of the first and second addition steps according to an embodiment of the present invention. Example 2 a2: In the first addition step, oxidized slime inhibitors are added intermittently at equal intervals. Example 2 b2: In the second addition step, organic slime inhibitors are continuously added during a period other than the addition period of the first addition step. The horizontal axis represents the operating period (hours), and the vertical axis represents the amount added. Furthermore, the operating period 0h of the first addition step and the operating period 0h of the second addition step can be set as the starting point for operation, respectively. (The following is omitted as it is not part of the original text.) Figure 1 The repeated parts in the description.

[0201] Furthermore, the intermittent addition periods in the first addition process can be the same or different periods, and the amount added in each intermittent period can be the same or different amounts. In addition, the intervals between intermittent additions can be the same or different intervals.

[0202] Alternatively, in the second addition step, the organic slime inhibitor may be added continuously for the entire period or a portion of the period other than the addition period of the first addition step. Alternatively, the organic slime inhibitor may be added discontinuously in the second addition step.

[0203] Furthermore, as an example 3 of the control of the first adding process and the second adding process involved in this embodiment, the control examples 1 and 2 can be combined, or these control examples 1 and 2 can be performed repeatedly or in a random order. For example, they can be performed in the order of control example 1 followed by control example 2, or control example 2 followed by control example 1. Alternatively, they can be performed in the order of control example 1, control example 2, and control example 2 again.

[0204] According to Example 2 of the control in this embodiment, treated water containing oxidative slime inhibitors and / or organic slime inhibitors can be produced. Furthermore, according to Example 2 of the control in this embodiment, the treated water containing oxidative slime inhibitors and / or organic slime inhibitors is supplied to the reverse osmosis membrane unit in the form of a first supply step and a second supply step. At this time, it can be controlled by... Figure 2In the same manner as shown in the addition patterns a2 and b2, treated water containing oxidative slime inhibitors and / or organic slime inhibitors is supplied to the reverse osmosis membrane unit. As a more specific example, treated water is supplied to the reverse osmosis membrane unit in the following order: treated water containing only organic slime inhibitors, treated water containing only oxidative slime inhibitors, and so on.

[0205] This allows water systems equipped with reverse osmosis membrane devices to operate more stably over longer periods. It also improves the reduction of slime within the reverse osmosis membrane and better inhibits the increase of slime, thereby better suppressing biological fouling.

[0206] The oxidative slime inhibitor and / or organic slime inhibitor can be added at the same or different locations (e.g., refer to...). Figure 3 The suitable location for adding the material is a reverse osmosis membrane unit that performs reverse osmosis membrane treatment, or upstream of it.

[0207] Furthermore, in order to perform safety filter treatment on the water supplied to the reverse osmosis membrane unit, when a safety filter unit is installed before the reverse osmosis membrane unit, the appropriate location for adding oxidative slime inhibitors and / or organic slime inhibitors is the safety filter unit or before or after it. More specifically, it is appropriate to install them at the safety filter unit or upstream of it, and more particularly, it is more appropriate to install them in the addition flow path between the safety filter unit and the treatment unit located upstream of it.

[0208] The safety filter device can perform the turbidity removal membrane treatment process described later, or it can be a turbidity removal membrane device. The safety filter device can appropriately use a membrane that can be used in a turbidity removal membrane device (such as a microfiltration (MF) membrane, etc.) as the safety filter.

[0209] This also inhibits sludge buildup within the safety filter unit and downstream of it, such as in the reverse osmosis membrane unit. Furthermore, it inhibits biological fouling in these membrane units, and further inhibits biological fouling in the reverse osmosis membrane unit. Therefore, the water system can operate stably for a longer period.

[0210] 1-4. Application of the operating method in this embodiment

[0211] The operating method described in this embodiment can be applied to reverse osmosis membrane devices. The method described in this embodiment can be applied to slime inhibition methods, biofouling inhibition methods, water systems, devices, or systems.

[0212] The steps involved in this embodiment can be applied to an apparatus or system. For example, the first step and the second step can also be respectively defined as a first method and a second method, a first apparatus and a second apparatus, or a first system and a second system.

[0213] The operation method described in this embodiment can be applied to water systems that have at least a reverse osmosis membrane device.

[0214] The water system that includes reverse osmosis membrane devices is not particularly limited, and examples include: water treatment systems; circulating water systems such as cooling towers; process water systems, water use systems, or wastewater recycling systems such as pulp manufacturing.

[0215] As an example of a water system including a reverse osmosis membrane device, the system may be configured sequentially or in a random order and include: a coagulation treatment step, in which raw water is fed in and a coagulant is injected into the raw water to cause turbidity and other substances to coagulate or flocculate; a solid-liquid separation step, in which the treated water containing the coagulated substances is separated into precipitate and supernatant; and a turbidity removal membrane treatment step, in which turbidity and other substances are removed from the incoming supernatant before the reverse osmosis membrane treatment. Furthermore, these treatment steps may also be performed using a treatment apparatus or treatment unit configured to perform the treatment steps separately.

[0216] As an example of a water system that includes a reverse osmosis membrane device, see reference for example. Figure 3 The water system 1 shown is described, but the water system involved in this embodiment is not limited to this. The water system 1, including the reverse osmosis membrane device 2, includes: a coagulation process performed by a coagulation treatment device 5, which is configured to allow raw water to flow in and inject a coagulant into the raw water to cause turbidity or other substances to coagulate or flocculate; a solid-liquid separation process performed by a solid-liquid separation device 4, which is configured to separate the treated water containing coagulated substances into precipitate and supernatant; a pretreatment process performed by a safety filter 3, which is configured to perform a turbidity removal membrane treatment to remove turbidity or other substances from the incoming supernatant before reverse osmosis membrane treatment; and a reverse osmosis membrane treatment process performed by the reverse osmosis membrane device 2, which is supplied with pretreated treated water containing oxidative slime inhibitors and / or organic slime inhibitors. In the reverse osmosis membrane treatment process, concentrated water and permeate can be separated.

[0217] Additionally, as an example of a water system including a reverse osmosis membrane device, a water treatment device (suitable for an ultrapure water device) can be listed below, the water treatment device including: a raw water supply path configured to supply raw water; and a reverse osmosis membrane device configured to separate the raw water supplied from the raw water supply path into permeate and concentrate.

[0218] Additionally, as an example of a water system including a reverse osmosis membrane device, a water treatment device can be listed below, comprising: a raw water supply path configured to supply raw water; a filtration device and a filtration treatment tank configured to filter the raw water supplied from the raw water supply path; a safety filter device configured to pretreat the filtered treated water as a pretreatment for reverse osmosis membrane treatment; and a reverse osmosis membrane device. The turbidity removal membrane treatment can also be performed using the safety filter device.

[0219] 1-4-1. Raw water

[0220] The raw water (e.g., the water to be treated) used in this embodiment is not particularly limited, and examples include industrial wastewater containing organic matter, seawater / saltwater, freshwater (river water, lake water, etc.), industrial water / tap water, etc.

[0221] The pH value of the raw water or the water to be treated is not particularly limited, but is preferably 3 to 9, more preferably 4 to 8, and even more preferably 5 to 8. The pH value can be adjusted using a pH adjuster.

[0222] There is no particular limitation on the temperature of the raw water or the water to be treated, but it is preferably 4℃ to 50℃, and more preferably 10℃ to 40℃.

[0223] The total organic carbon (TOC) of the raw water or the water being treated is not particularly limited, but is preferably 1 mg / L to 100 mg / L, more preferably 1 mg / L to 50 mg / L, and even more preferably 1 mg / L to 10 mg / L.

[0224] The oxidation-reduction potential (ORP) of the raw water or the water to be treated is preferably 200 mV to 600 mV, more preferably 200 mV to 400 mV.

[0225] 1-4-2. Reverse osmosis membrane device

[0226] The reverse osmosis membrane device used in this embodiment is not particularly limited, but it is suitable to be configured to remove ions or organic matter from the raw water using a reverse osmosis membrane. The reverse osmosis membrane device is suitable for use in seawater desalination, ultrapure water production, industrial water treatment, wastewater recycling, and wastewater reuse. Furthermore, the reverse osmosis membrane device may also include one or more units equipped with reverse osmosis membranes. Additionally, the water system may also have one or more reverse osmosis membrane devices.

[0227] <Reverse Osmosis Membrane>

[0228] The membrane used in this embodiment is a reverse osmosis membrane (hereinafter also referred to as "RO membrane") or a nanofiltration membrane (hereinafter also referred to as "NF membrane"). There is no particular limitation on the RO membrane; examples include polyamide-based, polyethersulfone-based, polysulfone-based, polyimide-based, polyethyleneimine-based, polyethylene oxide-based, and cellulose acetate-based membranes. Among these, polyamide-based RO membranes are particularly advantageous due to their high rejection rate of ionic substances and large flux.

[0229] The conditions for the treated water (hereinafter also referred to as "supply water") supplied to the reverse osmosis membrane device in this embodiment can be appropriately set according to the treatment capacity or purpose of the reverse osmosis membrane device or reverse osmosis membrane process, and there are no particular limitations.

[0230] Conditions for the treated water (feed water) supplied to the reverse osmosis membrane unit can include, for example, the pH value, flow rate, temperature, pressure (MPa), TOC (Total Organic Carbon), and ORP (Oxidation-Reduction Potential) of the feed water. One or more of these conditions can be selected. The organic matter content of the feed water is defined as TOC.

[0231] Furthermore, in this invention, the “treated water supplied to the reverse osmosis membrane device” is also referred to as “supply water”. The supply water refers to the water that is to be introduced into the reverse osmosis membrane device and treated by the reverse osmosis membrane, which is usually equivalent to the inlet water of the reverse osmosis membrane device.

[0232] The pH value of the supplied water is not particularly limited, but is preferably 3 to 9, more preferably 4 to 8, and even more preferably 5 to 8. The pH value can be adjusted using a pH adjuster.

[0233] There is no particular limitation on the water supply rate, but it is preferably 5 mL / min to 200 mL / min.

[0234] There is no particular limitation on the water pressure of the supply water, but it is preferably 0.1MPa to 10MPa.

[0235] There is no particular limitation on the temperature of the supplied water, but it is preferably 4℃ to 50℃, and even more preferably 10℃ to 40℃.

[0236] There is no particular limitation on the TOC of the water supply, but it is preferably 1 mg / L to 100 mg / L, more preferably 1 mg / L to 50 mg / L, and even more preferably 1 mg / L to 10 mg / L.

[0237] The ORP of the supplied water is preferably 200mV to 600mV, and more preferably 200mV to 400mV.

[0238] In addition, the preferred water flow rate is 3m / s per 8-inch spiral module. 3 / h~10m 3 / h.

[0239] In this embodiment, as a more suitable form, a pretreatment step may also be included, in which organic matter or turbidity is removed from the water to be treated by a pretreatment unit before the water to be treated is supplied to the reverse osmosis membrane device.

[0240] The water supplied to a reverse osmosis membrane unit is suitable for pretreatment using a safety filter device. For example, as a pretreatment step, one could list the process of filtering the raw water (the water to be treated) using a filtration device, and then passing the filtered water through a filtration tank and a safety filter.

[0241] Thus, pretreated water can be obtained for supplying to reverse osmosis membrane units or reverse osmosis membrane processes.

[0242] There are no particular limitations on the type of safety filter. Examples include single or multiple microfiltration membrane (MF) treatments, single or multiple ultrafiltration membrane (UF) treatments, etc. One or more of these can be used, or these can be appropriately combined. This reduces turbidity and other impurities in the water supplied to the reverse osmosis membrane unit.

[0243] In this embodiment, since the treated water supplied to the reverse osmosis membrane unit contains more readily oxidative and / or organic slime inhibitors, biofouling generated in the reverse osmosis membrane unit can be appropriately and more effectively suppressed. Furthermore, the effects of the oxidative and / or organic slime inhibitors (e.g., antibacterial, bactericidal, algicidal, microbial proliferation inhibition, microbial metabolic inhibition, etc.) can be appropriately and efficiently exerted. Therefore, the effectiveness in suppressing biofouling generated in the reverse osmosis membrane unit and the effects brought about by the chemicals used are also expected.

[0244] 1-5. Various determination methods

[0245] <Method for calculating total residual chlorine concentration>

[0246] Furthermore, the total residual chlorine concentration is calculated based on the following method. Additionally, it can be referenced to Japanese Industrial Standards (JIS) K 0400-33-10:1999.

[0247] Total residual chlorine concentration = free chlorine concentration + activated bound chlorine concentration + stabilized bound chlorine concentration.

[0248] Free chlorine concentration: Free chlorine concentration obtained using the DPD method (pocket residual chlorine meter, manufactured by HACH). [Here, the free chlorine concentration obtained using the DPD method is the chlorine concentration measured after 5 to 30 seconds (mg-Cl2 / L) using the free chlorine determination reagent, i.e., the DPD (Free) reagent.]

[0249] Activated bound chlorine concentration: The value obtained by subtracting the measured result of the free chlorine concentration (mg-Cl2 / L) from the chlorine concentration measured 300 seconds later using the free chlorine determination reagent, i.e., DPD (Free) reagent.

[0250] Stabilized bound chlorine concentration: The value obtained by subtracting the chlorine concentration measurement result (mg-Cl2 / L) obtained after 300 seconds using the free chlorine measurement reagent (DPD(Free) reagent) from the chlorine concentration measurement result (mg-Cl2 / L) obtained after 180 seconds using the total chlorine determination reagent (DPD(Total) reagent).

[0251] Free chlorine percentage (%) = (Free chlorine concentration / Total residual chlorine concentration) × 100

[0252] Stabilized bound chlorine ratio (%) = (stabilized bound chlorine concentration / total residual chlorine concentration) × 100

[0253] Furthermore, the temperature of the test environment was set at 25℃.

[0254] The pH value (25°C) of the treated water can be measured using a handheld pH meter manufactured by HORIBA. Additionally, the TOC of the treated water can be measured using a TOC meter. The ORP of the treated water can be measured using an ORP meter.

[0255] Furthermore, the operation method of the reverse osmosis membrane device involved in this embodiment can also be a reverse osmosis membrane treatment method. In addition, the operation method involved in this embodiment can be applied to a device or system.

[0256] Furthermore, regarding the operation method of the reverse osmosis membrane device involved in this invention, it is appropriate to omit the descriptions of the first step, the second step, the oxidative slime inhibitor, the organic slime inhibitor, and other structures that are repetitive with the structures described in "2." and "3." below. However, the descriptions in "2." and "3." are also applicable to this embodiment, and the structures described therein may be used appropriately.

[0257] 2. Sludge control method used in the reverse osmosis membrane device according to this embodiment.

[0258] Regarding the slime control method used in the reverse osmosis membrane device according to the present invention, it is appropriate to omit the descriptions of the first step, the second step, the oxidative slime inhibitor, the organic slime inhibitor, etc., which are repetitive with the structures described in "1." and "3." below. However, the descriptions in "1." and "3." are also applicable to this embodiment, and the structures described therein can be appropriately adopted. In addition, the slime control method according to this embodiment can be applied to a device or system.

[0259] The slime control method used in the reverse osmosis membrane device according to this embodiment is suitable to include: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0260] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0261] It is suitable that the concentration of the oxidative slime inhibitor during the first addition period is adjusted to be greater than the concentration of the organic slime inhibitor during the first addition period.

[0262] It is appropriate to add the aforementioned oxidative slime inhibitor more than once every 3 days during operation.

[0263] It is appropriate to add the oxidative slime inhibitor for at least 10 minutes each time.

[0264] It is appropriate to add the aforementioned oxidative slime inhibitor at a concentration of 0.1 mg / L or higher, based on the total chlorine concentration.

[0265] It is appropriate to add the aforementioned organic slime inhibitor at a concentration of 0.01 mg / L or higher.

[0266] 3. The water treatment apparatus involved in this embodiment

[0267] Regarding the water treatment apparatus involved in this invention, it is appropriate to omit the descriptions of structures such as the first process, the second process, the oxidative slime inhibitor, and the organic slime inhibitor that are repetitive with the structures described in "1." and "2.", but the descriptions of "1." and "2." are also applicable to this embodiment, and the structures described therein may be used appropriately.

[0268] Alternatively, the water treatment apparatus involved in this embodiment may also be a water treatment apparatus or water system having at least a reverse osmosis membrane device. The water treatment apparatus may also be a water treatment system or water treatment system.

[0269] The water treatment apparatus described in this embodiment is suitable for implementing the method of this embodiment, wherein the method of this embodiment comprises:

[0270] The first step involves intermittently adding an oxidative slime inhibitor and intermittently supplying the treated water containing the oxidative slime inhibitor to the reverse osmosis membrane unit; and

[0271] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0272] The water treatment apparatus described in this embodiment is suitable for the operation method of the reverse osmosis membrane device implemented in this embodiment, or the sludge control method used in the reverse osmosis membrane device of this embodiment.

[0273] The water treatment apparatus according to this embodiment preferably includes a first reagent addition unit, a second reagent addition unit, and a reverse osmosis membrane unit, and includes a control unit for controlling these units. Preferably, a safety filter unit is included as a pretreatment unit before the reverse osmosis membrane unit. The first and second reagent addition units are preferably connected to the upstream or downstream flow path of the safety filter unit and the upstream flow path of the reverse osmosis membrane unit, thereby allowing reagents to be added to the water to be treated and supplying the treated water containing the reagents to the reverse osmosis membrane unit. Furthermore, these units can be single or multiple, and they can also be an apparatus.

[0274] The following shows one example of the implementation of this embodiment, but the implementation of this embodiment is not limited to this. In addition, the implementation of this embodiment can be carried out by a control unit, or by a water treatment control device, water treatment device, water treatment system, water system, or other device.

[0275] As an example of this embodiment, a control unit configured to perform the first and second steps, or a device including such a control unit, is preferred. This allows for a better implementation of the method of this embodiment.

[0276] The control unit can control and implement the first and second processes by instructing the first and second reagent addition units on the conditions (addition sequence (e.g., intermittent, continuous), dosage, etc.) of adding oxidative and organic slime inhibitors to the water being treated.

[0277] In addition, the control unit can also use various measuring devices to monitor the supply status of the treated water containing the reagents to the reverse osmosis membrane device in the first and second processes, and can also feed back the measuring results to the first and second reagent addition processes as needed, and control these processes.

[0278] As a suitable configuration, the control unit can control and implement the first and second processes by instructing the first and second reagent addition units on more suitable reagent addition conditions (addition sequence (e.g., intermittent, continuous), addition concentration, etc.) based on the supply status. This allows for more stable long-term operation of the water system equipped with the reverse osmosis membrane device. Furthermore, this improves the reduction of slime present in the reverse osmosis membrane or better inhibits the increase of slime, thereby also better suppressing biological fouling.

[0279] As a more suitable configuration, it is preferable for the control unit to execute steps 11 and 21 concurrently, and even more preferable to execute steps 12 and 22 concurrently. Furthermore, the control unit can adjust the amount, timing, or duration of the addition of oxidative and organic slime inhibitors to the treated water in the first and second addition steps while preparing treated water containing oxidative and / or organic slime inhibitors. The control unit can supply the treated water containing oxidative and / or organic slime inhibitors prepared in the first and second addition steps to the reverse osmosis membrane unit during the first and second supply steps. In this way, the control unit can ensure the water system with the reverse osmosis membrane unit operates stably for a longer period. This also helps to suppress biological fouling and other build-up in the reverse osmosis membrane unit.

[0280] As part of step 11 of the first process, the control unit controls the first reagent addition unit by intermittently adding oxidative slime inhibitors to the water being treated in the water system. According to the instructions of the control unit, the first reagent addition unit intermittently adds oxidative slime inhibitors to the water being treated in the water system.

[0281] As part of the first process, step 12 involves the control unit intermittently supplying the treated water containing the oxidative slime inhibitor to the reverse osmosis membrane unit after addition.

[0282] As step 21 of the second process, the control unit controls the second agent addition unit to add the organic slime inhibitor during periods other than those in the first process. According to the control unit's instructions, the second agent addition unit adds the organic slime inhibitor during periods other than those in the first process.

[0283] As part of the second process, step 22, the control unit controls the process by supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit after the addition.

[0284] The control unit is suitably configured to instruct the first and second reagent addition units so that the addition concentration of the oxidative slime inhibitor (in terms of total chlorine concentration) is adjusted to be higher than that of the organic slime inhibitor (in terms of reagent mass concentration), thereby setting the desired reagent addition amount for each.

[0285] In addition, the control unit is suitable for instructing the first agent addition unit to add oxidized slime inhibitor more than once every 3 days during operation, thereby setting the desired addition period.

[0286] In addition, the control unit is suitable for instructing the first agent addition unit to add an oxidized slime inhibitor for at least 0.1 minutes each time, thereby setting the desired addition period.

[0287] As an example, such as Figure 3 As shown, the control unit (not shown) can control the first reagent addition device 10 and the second reagent addition device 20 included in the water system with a reverse osmosis membrane device. The control unit can instruct the first reagent addition device 10 to add an oxidative slime inhibitor upstream of the safety filter 3 or the reverse osmosis membrane device 2 according to a first procedure. The control unit can instruct the second reagent addition device 20 to add an organic slime inhibitor upstream of the safety filter 3 or the reverse osmosis membrane device 2 according to a second procedure. Thus, the control unit can supply treated water containing oxidative slime inhibitor and / or organic slime inhibitor to the reverse osmosis membrane device 2. In this way, by controlling and implementing the first and second addition procedures, the control unit can ensure the long-term stable operation of the water system with the reverse osmosis membrane device.

[0288] Furthermore, the method of this embodiment can also be implemented by an apparatus for implementing or managing the operation of the reverse osmosis membrane device, a slime control method, or other methods (e.g., the methods described in "1." and "2."), or by a control unit (including a central processing unit (CPU) or processor, etc.) included in the apparatus. Such apparatus or control units can be provided. Examples of such implementable or manageable apparatus include: computers, notebook computers, desktop personal computers, tablet personal computers (tabletPCs), programmable logic controllers (PLCs), servers, cloud services, etc. Furthermore, such implementable or manageable apparatus may appropriately include: input units such as touchscreens or keyboards, inter-unit transceivers or networks, communication units such as network access units, and display units such as touchscreens or displays. Thus, the method of this embodiment can be implemented. The apparatus for implementation or management may suitably include, for example, a CPU, random access memory (RAM), a storage unit, a display unit, and a communication unit as its structure, which may be connected as needed via, for example, a bus serving as a data transmission path.

[0289] Furthermore, the method of this embodiment can also be programmed and saved to hardware resources including storage media (such as non-volatile memory, solid-state drives (SSDs), hard disk drives (HDDs), compact discs (CDs), digital video discs (DVDs), Blu-ray discs, etc.) and implemented by the control unit. The method of this embodiment can be provided as a program. A storage medium storing the method of this embodiment can be provided. Therefore, the method of this embodiment can be implemented.

[0290] Additionally, devices, water treatment apparatuses, systems, or water systems may be provided that include the control unit, the storage medium, or the program, and are configured to operate the reverse osmosis membrane device or control sludge buildup in the reverse osmosis membrane device. These devices, water treatment apparatuses, systems, or water systems can thus be implemented. The method of this embodiment can be carried out accordingly. These devices, water treatment apparatuses, systems, or water systems can also be suitably configured in a corresponding manner depending on the purpose.

[0291] Furthermore, as an example of this embodiment, a program can be provided that enables a computer to operate a reverse osmosis membrane device or control sludge, including a first function and a second function. The first function is configured to intermittently add oxidative sludge inhibitors and intermittently supply treated water containing the oxidative sludge inhibitors to the reverse osmosis membrane device. The second function is configured to add organic sludge inhibitors during periods other than the addition period of the first step and supply treated water containing the organic sludge inhibitors to the reverse osmosis membrane device. The method is not limited to this. Thus, the method of this embodiment can be implemented.

[0292] Furthermore, in the procedures involved in this embodiment, it is appropriate to omit the descriptions of the first step, the second step, the oxidative slime inhibitor, the organic slime inhibitor, and other structures that are repetitive with the structures described in “1.”, “2.”, etc., but the descriptions of “1.”, “2.”, etc. are also applicable to this embodiment, and the structures described therein may be used appropriately.

[0293] This technology can adopt the following structure.

[0294] [1] A method for operating a reverse osmosis membrane device, comprising: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0295] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0296] [2] A method for controlling slime in a reverse osmosis membrane device, comprising: a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane device; and

[0297] The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit.

[0298] ·〔3〕According to the method described in 〔1〕 or 〔2〕, the concentration of the oxidative slime inhibitor is adjusted to be higher than that of the organic slime inhibitor.

[0299] ·〔4〕The method described in any one of 〔1〕 to 〔3〕, wherein the oxidative slime inhibitor is added more than once every 3 days during operation.

[0300] · [5] The method described in any one of [1] to [4], wherein the oxidative slime inhibitor is added for more than 10 minutes each time.

[0301] · [6] The method described in any one of [1] to [5], wherein the oxidative slime inhibitor is added at a concentration of 0.1 mg / L or more based on the total chlorine concentration.

[0302] · [7] The method described in any one of [1] to [6], wherein the organic slime inhibitor is added at a concentration of 0.01 mg / L or more.

[0303] · [8] The method according to any one of [1] to [7], wherein the oxidative slime inhibitor is a halogenated agent, preferably selected from one or more of chloramine compounds, stabilized bromides and halogenated hydantoin compounds, more preferably chloramine compounds and / or stabilized bromides.

[0304] · [9] The method according to any one of [1] to [8], wherein the organic slime inhibitor is one or more selected from isothiazolinium compounds, halocyanoacetamide compounds, aldehyde compounds, and oxime compounds, preferably one or more selected from 2,2-dibromo-3-azoxypropionamide (DBNPA), 5-chloro-2-methyl-4-isothiazolin-3-one (Cl-MIT), 2-methyl-4-isothiazolin-3-one (MIT), and glutaraldehyde.

[0305]

[10] A water treatment apparatus or water treatment system that implements an operation method of a reverse osmosis membrane device according to any one of [1] and [3] to [9], or a sludge control method applied in a reverse osmosis membrane device according to any one of [2] to [9]. The water treatment apparatus or water treatment system preferably has at least a reverse osmosis membrane device, and further preferably has a safety filter device upstream of the reverse osmosis membrane device. Additionally, it is preferable to have a safety filter device for pre-treating the water before it is supplied to the reverse osmosis membrane device, thereby allowing the treated water treated by the safety filter to be supplied to the reverse osmosis membrane device.

[0306]

[11] may also include a water treatment apparatus or water treatment system configured to implement the method described in any one of [1] to [9], or a control unit or control device, the control unit may also include a CPU, and the control device is preferably a computer device. It may also be a water treatment apparatus or water treatment system having the control unit or the control device.

[0307] ·

[12] An operating system for a reverse osmosis membrane device or a sludge control system used in a reverse osmosis membrane device, which causes a computer to implement the method described in any one of [1] to [9].

[0308] ·

[13] A program that causes a computer to perform the method described in any one of [1] to [9].

[0309]

[14] A program or a computer-readable medium storing the program, or an apparatus containing the program or the medium, the program causing a computer to operate a reverse osmosis membrane apparatus including a first function and a second function, the first function performing a first step of intermittently adding an oxidative slime inhibitor and intermittently supplying treated water containing the oxidative slime inhibitor to the reverse osmosis membrane apparatus.

[0310] The second function performs a second step of adding an organic slime inhibitor during a period other than the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit. A control unit, water treatment apparatus, control system, and water treatment system are configured to implement the procedure.

[0311] [Example]

[0312] The following examples and comparative examples illustrate the implementation of the present invention. However, the scope of the present invention is not limited to these examples.

[0313] <Experimental Example 1>

[0314] A substrate is added to the raw water to promote microbial-based biofouling. Specifically, ethanol (calculated as C) at 50 mg / L, ammonium chloride (calculated as N) at 10 mg / L, and sodium dihydrogen phosphate (calculated as P) at 0.5 mg / L are added to the raw water as a substrate, and the resulting substance is used as the treated water. The raw water (treated water) has a pH of 6–8, a TOC of 1 mg / L, an ORP of 300 mV, and a temperature of 25°C.

[0315] The water to be treated is pressurized to 1.5 MPa using a pump and supplied as feed water (flow rate 100 mL / min, pressure 0.2 MPa, temperature 25°C) to the concentrate chamber of the RO membrane unit for RO membrane treatment. The RO membrane unit is constructed by filling a single vessel with 4-inch spiral RO membrane modules (manufactured by Nitto Denko Corporation, ES20) of an aromatic polyamide RO membrane. The flow rate of the supply water is 3 m / s per 8-inch spiral module. 3 / h~10m 3 / h. The so-called differential pressure change refers to the change in pressure between the initial pressure (set to 0 kPa) and the pressure at each subsequent water flow time.

[0316] <Evaluation Methods for Sliming Inhibition in Reverse Osmosis Membranes>

[0317] In evaluating the slime suppression effect on reverse osmosis membranes, a membrane fouling simulator described in Non-Patent Literature 1 (JS Vrouwenvelder et al.) was used. Under the conditions recorded in Table 1, the number of days required for the differential pressure to increase by 100 kPa was measured. The day the differential pressure was reached was defined as the day biological fouling occurred, i.e., the occlusion day. The evaluation was that the longer the number of days leading to occlusion, the better the slime suppression.

[0318] [Comparative Example 1-1]: No drugs added

[0319] [Comparative Examples 1-2]: Sodium monochloramine sulfonate was added separately from day 0 until occlusion at an amount of 1.5 mg / L based on the total chlorine concentration (T-Cl).

[0320] Comparative Example 3: Cl-MIT was added at a dose of 0.15 mg / L (calculated as Cl-MIT) from day 0 until occlusion.

[0321] [Example 1-1]: The first process of <J1-1> and the second process of <J2-2> are performed in parallel.

[0322] In <J1-1>, starting from day 0, sodium monochloramine sulfonate, as an oxidative slime inhibitor, is added to the treated water every 2 hours at a rate of 6 mg / L based on T-Cl, starting at 8:00 AM each day, and the treated water containing the agent is supplied to the RO membrane device.

[0323] In <J2-2>, starting from day 0, Cl-MIT (5-chloro-2-methyl-4-isothiazolin-3-one), an organic slime inhibitor, is continuously added at a concentration of 0.15 mg / L (Cl-MIT mass concentration), and the treated water containing this agent is supplied to the RO membrane unit. In the case of continuous addition, the agent is added to the treated water from day 0 until clogging occurs, without stopping the addition, and the treated water containing this agent is supplied to the reverse osmosis membrane unit. During the period when the addition periods of <J1-1> and <J2-2> are repeated, the treated water containing these agents is supplied to the RO membrane unit.

[0324] <Preparation of pharmaceuticals containing sodium monochloramine sulfonate>

[0325] A sodium hydroxide aqueous solution was prepared using pure water with sodium hydroxide (manufactured by Kishida Chemical Co., Ltd.) at 48% by mass. 19.5 g of the pre-prepared sodium hydroxide aqueous solution was mixed with 7.5 g of pure water, and then 15.0 g of ammonium sulfonic acid (manufactured by Kishida Chemical Co., Ltd.) was added and mixed. Subsequently, 58.0 g of sodium hypochlorite (manufactured by Asahi Glass Co., Ltd.) with an effective chlorine concentration of 12% by mass was added and mixed to prepare a monochloramine sulfonic acid reagent. Furthermore, the total chlorine concentration of this reagent, calculated as Cl2, was 7% by mass.

[0326] [Table 1]

[0327] Table 1: Experimental Example 1

[0328]

[0329] Based on the water flow results shown in Table 1, the following can be confirmed.

[0330] It can be confirmed that it is better to alternate between adding different systems of slime inhibitors every few days than to continuously add a single slime inhibitor.

[0331] It can be confirmed that by performing the first addition process of intermittently adding oxidative slime inhibitor once a day for 2 hours, and the second addition process of continuously adding organic slime inhibitor, the number of days of blockage is increased and the slime inhibition effect is better.

[0332] <Experimental Example 2>

[0333] The treated water was prepared by adding isopropyl alcohol (IPA) at a concentration of 1.4 mg / L (C) and sodium dihydrogen phosphate at a concentration of 0.02 mg / L (P) to the raw water as a matrix. The water temperature of the treated water was set to 30°C, and the following conditions were used as the conditions for adding the bactericide. Otherwise, the test was conducted under the same conditions as in <Experimental Example 1>.

[0334] [Comparative Example 2-1]

[0335] Cl-MIT, an organic slime inhibitor, is continuously added at a concentration of 0.1 mg / L and continuously fed into the RO membrane unit. Thus, the treated water containing the reagent is continuously fed into the downstream RO membrane unit.

[0336] [Example 2-1]

[0337] The following operations are repeated sequentially: continuously adding the second-stage organic slime inhibitor for a "certain time", and then, during the period when the addition of the second-stage organic slime inhibitor stops, continuously adding the first-stage oxidative slime inhibitor for a "certain time".

[0338] Therefore, oxidative slime inhibitors are intermittently added, and treated water containing the oxidative slime inhibitors is continuously passed through the reverse osmosis membrane unit for a "certain period of time". On the other hand, organic slime inhibitors are continuously added during "periods other than the addition period of the first step", and treated water containing the organic slime inhibitors is continuously passed through the reverse osmosis membrane unit during "periods other than the addition period of the first step".

[0339] Specifically, Cl-MIT, used as an organic slime inhibitor in the second process, is continuously added at a concentration of 0.1 mg / L (Cl-MIT) for 23.5 hours from 9:30 AM to 9:00 AM the following day, and water is continuously fed into the downstream RO membrane unit during the specified period. Meanwhile, monochloroamine sulfonic acid, used as an oxidative slime inhibitor in the first process, is continuously added at a concentration of 5 mg / L (T-Cl) for 0.5 hours from 9:00 AM to 9:30 AM, and water is continuously fed into the downstream RO membrane unit during the specified period. Thus, treated water containing organic slime inhibitors, treated water containing oxidative slime inhibitors, treated water containing organic slime inhibitors… are supplied to the reverse osmosis membrane unit in the following order:

[0340] The results of the differential pressure changes (kPa) up to 6 days in Examples 2-1 and Comparative Examples 2-1 are shown in... Figure 4 In Example 2-1, the pressure differential increase was noticeably sluggish, indicating that the method in Example 2-1 possesses excellent slime-inhibiting properties. Furthermore, in Example 2-1, even with low concentrations of both organic and oxidative slime inhibitors, the pressure differential remained below 10 kPa even after 6 days, resulting in very good slime inhibition. This effectively confirms that even at low concentrations of both organic and oxidative slime inhibitors, effective slime inhibition is achieved.

[0341] <Experimental Example 3>

[0342] The treated water was prepared by adding 50 mg / L of ethanol (calculated as C), 20 mg / L of ammonium chloride (calculated as N), and 1.0 mg / L of sodium dihydrogen phosphate (calculated as P) to the raw water as a matrix. The bactericide addition conditions were as follows, and the test was conducted under the same conditions as in <Experimental Example 1>.

[0343] [Comparative Example 3-1]

[0344] Cl-MIT, an organic slime inhibitor, is continuously added at a concentration of 0.5 mg / L, and water is continuously passed through the RO membrane unit. This process continuously feeds the treated water containing the reagent into the downstream RO membrane unit.

[0345] [Example 3-1]

[0346] The following operations are performed in parallel: the organic slime inhibitor of the second process is added continuously "once" and the oxidized slime inhibitor of the first process is added continuously "at certain intervals and at certain times".

[0347] Therefore, oxidative slime inhibitors are intermittently added, and treated water containing the oxidative slime inhibitors is continuously passed through the reverse osmosis membrane unit for a "certain period of time". On the other hand, organic slime inhibitors are continuously added "constantly" for at least "a period other than the addition period of the first step", and treated water containing the organic slime inhibitors is continuously passed through the reverse osmosis membrane unit "constantly". Thus, treated water containing organic slime inhibitors, treated water containing both oxidative and organic slime inhibitors, and treated water containing organic slime inhibitors are supplied to the reverse osmosis membrane unit in the following order: treated water containing organic slime inhibitors, treated water containing both oxidative and organic slime inhibitors, and treated water containing organic slime inhibitors...

[0348] Specifically, in the second step, Cl-MIT, an organic slime inhibitor, is continuously passed through water at a concentration of 0.5 mg / L (Cl-MIT by mass), and the treated water containing the reagent is continuously passed through the downstream RO membrane unit. Furthermore, in the first step, monochloroamine sulfonic acid, an oxidative slime inhibitor, is continuously added at a concentration of 25 mg / L (T-Cl) for one hour every other day, and the treated water containing the reagent is continuously passed through the downstream RO membrane unit for a specified period.

[0349] The results from Example 3-1 and Comparative Example 3-1 up to day 19 are shown below. Figure 5 In Example 3-1, the pressure differential increase was noticeably sluggish, thus indicating that the method in Example 3-1 possesses excellent slime-inhibiting properties. Furthermore, although Example 3-1 was implemented with a high concentration of oxidative slime inhibitor, the pressure differential change remained below 10 kPa even after 16 days, resulting in very good slime inhibition. Therefore, it was effectively confirmed that the slime-inhibiting function can be effectively performed.

[0350] <Experimental Example 4>

[0351] The treated water was prepared by adding ethanol (calculated as C) at a concentration of 30 mg / L, ammonium chloride (calculated as N) at a concentration of 10 mg / L, and sodium dihydrogen phosphate (calculated as P) to the raw water as a matrix. The water temperature of the treated water was set to 20°C, and the addition period and concentration of the slime inhibitor were set as shown in Table 2. Otherwise, the test was conducted under the same conditions as in <Experimental Example 1>.

[0352] In Table 2, under "Intermittent Addition (9:00-9:30 daily)," the oxidative slime inhibitor is continuously added during the period of 9:00-9:30 daily, and no addition is made during the period of 9:30-9:00 the following day. The oxidative slime inhibitor is continuously added for "30 minutes," and the treated water containing the agent is continuously passed through the downstream RO membrane unit for "30 minutes."

[0353] In Table 2, under "Intermittent Addition (21:00-21:30 daily)," the organic slime inhibitor is continuously added during the period of 21:00-21:30 daily, but not during the period of 21:30-21:00 the following day. The organic slime inhibitor is continuously added for "30 minutes," and the treated water containing the agent is continuously passed through the downstream RO membrane unit for "30 minutes."

[0354] In Table 2, "Continuously Added" means that the reagent is added continuously from the start of the test until the end of the test. During this period, the reagent is added continuously, and the treated water containing the reagent is continuously passed through the RO membrane unit.

[0355] In addition, in Comparative Examples 4-6, 4-7, and 4-1, as shown in Table 2, the first and second processes were performed in parallel.

[0356] Table 2 below shows the drug addition conditions and the number of days required to reach a differential pressure of 100 kPa. As shown in Table 2, the following results were obtained: This suggests that the treatment involving the parallel, intermittent addition of oxidative slime inhibitors in the first addition step and the continuous addition of organic slime inhibitors in the second addition step resulted in the longest occlusion period and the best slime inhibition effect.

[0357] [Table 2]

[0358] Table 2: Experimental Case 4

[0359]

Claims

1. A method of operating a reverse osmosis membrane device for obtaining permeate water from treated water containing oxidative slime inhibitors and / or organic slime inhibitors through reverse osmosis membrane treatment, comprising: a first step of intermittently adding oxidative slime inhibitors and intermittently supplying treated water containing the oxidative slime inhibitors to the reverse osmosis membrane device; and The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit. The concentration of the oxidative slime inhibitor is adjusted to be higher than that of the organic slime inhibitor. The concentration of the oxidative slime inhibitor, based on the total chlorine concentration, is 0.1 mg / L to 600 mg / L, and the concentration of the organic slime inhibitor, based on the total chlorine concentration, is 0.01 mg / L (based on reagent mass) to 100 mg / L (based on reagent mass). The oxidative slime inhibitor is a reagent containing at least one of chloroamine sulfonic acid, chloroamine sulfonate, bromoamine sulfonic acid, and bromoamine sulfonate. The organic slime inhibitor is a drug agent selected from one or more of isothiazolinone compounds, halocyanoacetamide compounds, aldehyde compounds and oxime compounds; The first process has a first intermittent addition period per unit and a first no-addition period per unit, wherein the first intermittent addition period per unit is shorter than the first no-addition period per unit.

2. The method of operating the reverse osmosis membrane device according to claim 1, wherein the oxidative slime inhibitor is added more than once every 3 days during operation.

3. The method of operating the reverse osmosis membrane device according to claim 1 or 2, wherein the oxidative slime inhibitor is added for at least 10 minutes each time.

4. The method of operating the reverse osmosis membrane device according to claim 1 or 2, wherein the first intermittent addition period for each unit is 10 minutes to 300 minutes.

5. The method of operating the reverse osmosis membrane device according to claim 1 or 2, wherein the first additive-free period for each unit is 5 to 100 hours.

6. A slime control method used in a reverse osmosis membrane device for permeate obtained from treated water containing oxidative slime inhibitors and / or organic slime inhibitors after reverse osmosis membrane treatment, comprising: a first step of intermittently adding oxidative slime inhibitors and intermittently supplying treated water containing the oxidative slime inhibitors to the reverse osmosis membrane device; and The second step involves adding an organic slime inhibitor during a period other than at least the addition period of the first step, and supplying the treated water containing the organic slime inhibitor to the reverse osmosis membrane unit. The concentration of the oxidative slime inhibitor is adjusted to be higher than that of the organic slime inhibitor. The concentration of the oxidative slime inhibitor is 0.1 mg / L to 600 mg / L based on the total chlorine concentration, and the concentration of the organic slime inhibitor is 0.01 mg / L to 100 mg / L based on the reagent mass concentration. The oxidative slime inhibitor is a reagent containing at least one of chloroamine sulfonic acid, chloroamine sulfonate, bromoamine sulfonic acid, and bromoamine sulfonate. The organic slime inhibitor is a drug agent selected from one or more of isothiazolinone compounds, halocyanoacetamide compounds, aldehyde compounds and oxime compounds; The first process has a first intermittent addition period per unit and a first no-addition period per unit, wherein the first intermittent addition period per unit is shorter than the first no-addition period per unit.

7. A water treatment apparatus that implements the operation method of the reverse osmosis membrane device as described in claim 1 or 2, or the sludge control method used in the reverse osmosis membrane device as described in claim 6.

Images