JP6819781B2 - Reverse osmosis membrane treatment method, water-based biofouling suppression method and equipment for that purpose - Google Patents

Description

The present invention relates to a method for treating a reverse osmosis membrane, an apparatus for producing a reaction solution containing a bound halogen, a method for suppressing biofouling in an aqueous system, and the like.

In treated water systems, it is common practice to treat water to be treated with a reverse osmosis (RO) membrane for the purpose of producing industrial water and ultrapure water, collecting and reusing wastewater, and desalinating seawater and brackish water. ing.
However, microorganisms contained in the water to be treated proliferate in the water flow pipe of the reverse osmosis membrane treatment device and on the membrane surface of the reverse osmosis membrane to form slime, which causes fouling such as a decrease in the amount of permeated water in the reverse osmosis membrane. May cause. As a countermeasure, oxidizing agents such as hydrogen peroxide solution, bound halogen agent, and halogen agent are used for suppressing the growth of microorganisms and decomposing organic substances.
For example, in order to prevent reverse osmosis membrane fouling due to the growth of microorganisms, a free chlorine agent and a stabilizer are added to the water to be treated to generate stabilizing bond chlorine in the water to be treated, and the stabilizing bond is generated. Water to be treated containing chlorine is supplied to the reverse osmosis membrane, or water to be treated containing chloramine is added to the reverse osmosis membrane.

Further, even in plant cooling water systems, wastewater treatment water systems, steel water systems, paper pulp water systems, cutting oil water systems, etc. of various factories, biofilms and the like are generated in water systems due to microorganisms (for example, bacteria, filamentous fungi, algae, etc.). It is said that these biofilms and the like cause a decrease in thermal efficiency; blockage of water flow pipes, flow paths, membranes (for example, RO membranes, etc.); and corrosion of pipe metal materials.

Further, for example, in Patent Document 1, in a method of supplying a liquid to be treated to a permeable membrane to perform membrane separation, a free chlorine agent is added to the liquid to be treated for sterilization, and then ammonium ions are added. A membrane separation method has been proposed, which comprises producing chloramine and suppressing the growth of microorganisms.

JP-A-1-104310

Here, as shown in Comparative Example 1 described later, when a chlorine-based oxidizing agent and a stabilizer are added to the water to be treated to generate bound chlorine, the free chlorine concentration in the water to be treated is 0.2 mg-. It was about Cl ₂ / L. For example, when water to be treated containing a free chlorine concentration of about 0.2 mg-Cl ₂ / L is supplied to a reverse osmosis membrane for the purpose of preventing biofouling, the reverse osmosis membrane has low chlorine resistance. The osmosis membrane tends to deteriorate. Further, for example, since free chlorine causes corrosion, it is preferable that the free chlorine concentration in the water system is small because corrosion of the water system (for example, a water flow pipe or a flow path) can be suppressed.

Further, it is conceivable to reduce the concentration of free chlorine in the water to be treated by lengthening the time until the water to be treated containing free chlorine reaches the reverse osmosis membrane treatment as much as possible. However, as in Comparative Example 1, the free chlorine concentration in the water to be treated hardly decreased even when the water to be treated in which about 0.2 mg-Cl ₂ / L of free chlorine was generated was allowed to elapse for a certain period of time. From this, even if time passes, the effect of reducing the free chlorine concentration in the water system (for example, the water to be treated) is hardly obtained. In addition, if the effect of reducing the free chlorine concentration is hardly obtained even after a lapse of time, even in a water system such as a circulating water system (for example, a water flow pipe or a flow path), corrosion occurs due to the free chlorine existing in the water system. It can occur.

In addition, a method of significantly increasing the amount of sulfamic acid added as a stabilizer to reduce free chlorine can be considered. However, as in Comparative Example 2, the free chlorine concentration in the water to be treated remained at about 0.2 mg-Cl ₂ / L even when the stabilizer concentration was increased by one order. From this, even if the amount of the stabilizer added is significantly increased, the effect of reducing the free chlorine concentration in the water system (for example, the water to be treated) is limited.

Therefore, it is a main object of the present invention to provide a technique for reducing the free halogen concentration in an aqueous system as much as possible even when a halogen-based oxidizing agent and a stabilizer are used in the aqueous system.

As a result of diligent studies, the present inventor has made a reaction solution in which a halogen-based oxidant and a stabilizer are reacted so as to have a total residual halogen concentration of a predetermined value or higher before adding to an aqueous system (for example, water to be treated). By producing and adding the reaction solution to an aqueous system (for example, water to be treated), the free halogen concentration (specifically, free chlorine concentration) in the aqueous system (for example, water to be treated) is significantly reduced. We found what we could do and completed the present invention.

In the present invention, a reaction solution obtained by reacting a stabilizer and a halogen-based oxidizing agent so that the total residual halogen concentration becomes 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate a bound halogen is applied to water to be treated. It provides a method of adding and treating the water to be treated with a reverse osmosis membrane.
Further, in the present invention, a reaction solution obtained by reacting a stabilizer and a halogen-based oxidant so that the total residual halogen concentration becomes 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate a bound halogen is applied to an aqueous system. It is added to provide a method of suppressing water-based biofouling.
The present invention is an apparatus for producing a reaction solution containing a bonded halogen.
A generator that reacts a stabilizer and a halogen-based oxidant to produce a reaction solution containing a bound halogen.
A control unit that adjusts the stabilizer and halogen-based oxidant so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration in the reaction solution.
To provide a manufacturing apparatus having the above.
The stabilizer may be a sulfamic acid compound.
The stabilizer may react with 1 mol of the halogen-based oxidizing agent in an amount of 1 mol or more.
The free halogen ratio (%) in the reaction solution may be 10% or less of the total residual halogen.
The total residual halogen concentration may be 125 mg-Cl ₂ / L or more.
The reaction solution containing the bonded halogen may be a reaction solution for suppressing fouling of a reverse osmosis membrane or a reaction solution for suppressing biofouling of an aqueous system.

The present invention can provide a technique for reducing the concentration of free halogen in a water system (for example, water to be treated) as much as possible even when a halogen-based oxidizing agent and a stabilizer are used in a water-treated water system. The effects described here are not necessarily limited, and may be any of the effects described in the present specification.

It is a figure which shows the bonding state of chlorine in the solution (reaction solution) at the time of dilution and mixing of a stabilizer and a chlorine-based oxidizing agent. Vertical axis: Chlorine abundance ratio (%) (◆ Stabilized bound chlorine, □ Free chlorine), Horizontal axis: Total residual halogen concentration in reaction solution (mg-Cl ₂ / L). As an example of the embodiment of the present invention, in an aqueous system, a reaction solution obtained by mixing a stabilizer and a halogen-based oxidizing agent and reacting them so that the total residual halogen concentration becomes a predetermined value or more is prepared in front of the reverse osmosis membrane treatment system. , Is a flow chart in the case of adding to the water to be treated and treating the water to be treated with a reverse osmosis membrane.

Preferred embodiments of the present invention will be described. However, the present invention is not limited to the following preferred embodiments, and can be freely modified within the scope of the present invention. It should be noted that the embodiments described below show an example of typical embodiments of the present invention, and the scope of the present invention is not limited and interpreted thereby. Further, the upper limit value and the lower limit value of each numerical value range can be arbitrarily combined as desired.

In the method for treating a reverse osmosis membrane according to the embodiment of the present invention, a stabilizer and a halogen-based oxidizing agent are reacted so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration to obtain bound halogen. The generated reaction solution is added to the water to be treated, and the water to be treated is subjected to reverse osmosis membrane treatment.
Further, in the method for suppressing water-based biofouling according to another embodiment of the present invention, the total residual halogen concentration of the stabilizer and the halogen-based oxidizing agent is 100 mg-Cl ₂ / L or more as the total chlorine concentration. The reaction solution obtained by reacting with the above to generate a bound halogen is added to the aqueous system.
In a narrow sense, "Biofouling" means a phenomenon in which microorganisms grow on a membrane used for water treatment and the like, and a substance derived from the microorganism such as a biofilm clogs the membrane. .. However, in the present invention, "Biofouling" includes not only the phenomenon of clogging the membrane but also microbial stains (slime) in water systems such as cooling towers and pulp and paper manufacturing processes.

<Stabilizer>
The "stabilizer" used in the present embodiment is not particularly limited as long as it can react with a halogen-based oxidizing agent described later to produce a bonded halogen (preferably a stabilized bonded halogen) described later. A compound having an amino group is preferable. In the present specification, a monovalent functional group (-NH ₂ , -NHR, -NRR') obtained by removing hydrogen from ammonia, a primary amine or a secondary amine is referred to as an "amino group".

As the stabilizer, for example, a sulfamic acid compound such as sulfamic acid or a derivative thereof; a hydridein such as 5,5'-dimethylhydantoin; isocyanuric acid; urea; biuret; methyl carbamate; ethyl carbamate ;, acetamide, nicotinic acid. Amide compounds such as amides, methanesulfonamides and toluenesulfonamides; imide compounds such as maleimide, succinimide and phthalimide; amino acids such as alanine, glycine, histidine, lysine, treonine, ornithine and phenylalanine; methylamine, hydroxylamine, morpholin , Amines such as piperazine, imidazole and histamine, aminomethanesulfonic acid, taurine; ammonia; ammonium salts such as ammonium sulfate and the like. The example of the stabilizer is also an example of a chlorine stabilizer that easily produces stabilized bonded chlorine.
One or more of these may be selected and used alone, or two or more may be used in combination.

Among the stabilizers, sulfamic acid compounds and / or organic nitride compounds (for example, amino acids, amide compounds, etc.) are preferable. A sulfamic acid compound is more preferable, and the free chlorine concentration can be reduced by using the sulfamic acid compound. By using the sulfamic acid compound, deterioration of the reverse osmosis membrane can be suppressed more appropriately, and corrosion of the water system can be suppressed more appropriately. Further, in the present embodiment, it is possible to appropriately exert the effect caused by the bound halogen (for example, the fouling of the reverse osmosis membrane can be better prevented).

Examples of the sulfamic acid compound include a compound represented by the following general formula [1] or a salt thereof.

R ¹ R ² NSO ₃ H ... [1]
(However, in the general formula [1], R ¹ and R ² are independently hydrogen atoms or hydrocarbons having 1 to 8 carbon atoms.)
Examples of the hydrocarbon having 1 to 8 carbon atoms include an aromatic group which may have a substituent (more preferably a phenyl group), an alkyl group which may have a substituent (more preferably a methyl group), and the like. Can be mentioned.

Examples of the sulfamic acid compound represented by the general formula [1] include N-methylsulfamic acid, N, N-dimethylsulfamic acid, and N, in addition to sulfamic acid in which both R ¹ and R ² are hydrogen atoms. -Phenylsulfamic acid and the like and salts thereof and the like can be mentioned.

The salt of the compound may be a general one, and may be an inorganic salt (metal salt such as alkali metal salt, alkaline earth metal salt, iron salt, zinc salt; ammonium salt, etc.) or an organic salt (carboxylate, etc.). Can be mentioned.
Examples of inorganic salts of the above compounds include alkali metal salts (eg, sodium salts, potassium salts, etc.), alkaline earth metal salts (eg, calcium salts, strontium salts, barium salts, etc.), and other metal salts (eg, calcium salts, strontium salts, barium salts, etc.). Manganese salt, copper salt, zinc salt, iron salt, cobalt salt, nickel salt, etc.), ammonium salt, guanidine salt, etc. can be mentioned.

Specific examples of the sulfamate include sodium sulfamate, potassium sulfamate, calcium sulfamate, strontium sulfamate, barium sulfamate, iron sulfamate, zinc sulfamate, ammonium sulfamate and the like.
One or two or more of the sulfamic acid compounds may be selected and used alone, or two or more of them may be used in combination.

<Halogen oxidizer>
The halogen-based oxidizing agent used in the present embodiment is not particularly limited, and examples thereof include chlorine-based, bromine-based, and reactants of a bromine compound and a chlorine-based oxidizing agent. The halogen-based oxidizing agent may be either chlorine-based or bromine-based, but the chlorine-based oxidizing agent is preferable from the viewpoint of easily exerting the effect of the present invention.

The chlorine-based oxidizing agent used in the present embodiment is not particularly limited, and is, for example, chlorine gas, chlorine dioxide, hypochlorous acid or a salt thereof, chloric acid or a salt thereof, chloric acid or a salt thereof, perchloric acid or a salt thereof. Examples thereof include salts, chlorinated isocyanuric acid and salts thereof. Of these, hypochlorite is preferable from the viewpoint of easy handling and the effect of the present invention. One or more of these may be selected and used alone, or two or more may be used in combination.

Specific examples of the salt form of the chlorine-based oxidizing agent include, for example, an alkali metal hypochlorite salt (for example, sodium hypochlorite, potassium hypochlorite, etc.) and an alkaline earth metal hypochlorite salt (for example,). , Calcium hypochlorite, barium hypochlorite, etc.), alkali metal chlorite salts (eg, sodium chlorate, potassium chlorate, etc.), alkaline earth metal chlorite (eg, chloric acid) Barium, etc.), other metal chlorite salts (eg, nickel chlorate, etc.), alkali metal chlorate salts (eg, ammonium chlorate, sodium chlorate, potassium chlorate, etc.), alkaline earth metal chlorate salts (For example, calcium chlorate, barium chlorate, etc.) and the like can be mentioned.
One or more of these may be selected and used alone, or two or more may be used in combination.
Further, the hypochlorite alkali metal salt and the hypochlorite alkaline earth metal salt may be those obtained by electrolyzing a sodium chloride-containing liquid such as seawater.

The bromine-based oxidizing agent used in the present embodiment is not particularly limited, and examples thereof include liquid bromine, bromine chloride, bromic acid or a salt thereof, hypobromous acid or a salt thereof, and the like. One or more of these may be selected and used alone, or two or more may be used in combination. The salt may be any salt that can be generally used, and for example, the above-mentioned salt (for example, an alkali metal salt) may be used.
In the present embodiment, as the halogen-based oxidizing agent, a bromine compound, a chlorine-based oxidizing agent, and a reactant can be used. Here, as the bromine compound, sodium bromide, potassium bromide, lithium bromide and hydrobromic acid, particularly sodium bromide can be preferably used. As the chlorine-based oxidizing agent, the above-mentioned chlorine-based oxidizing agent, particularly sodium hypochlorite, can be preferably used.

<Bound halogen>
The bound halogen is a compound produced by reacting a halogen-based oxidizing agent such as hypochlorous acid with ammonia or an amino compound, and is an oxidizing agent having a weaker oxidizing power than a free halogen such as free chlorine.
The bound halogen used in the present embodiment is not particularly limited, but is a compound detected by the stabilized bound chlorine concentration and / or the activated bound chlorine concentration described later, and is particularly detected as the stabilized bound chlorine concentration. Is more preferable.
In this embodiment, the bound halogen detected as the stabilized bound chlorine concentration is described as stabilized bound chlorine.

<Reaction solution>
In the present embodiment, it is preferable to use a reaction solution obtained by reacting the stabilizer and the halogen-based oxidizing agent so that the total residual halogen concentration becomes a predetermined concentration of 100 mg-Cl ₂ / L or more as the total chlorine concentration. Is. In the reaction solution, the stabilizer and the halogen-based oxidant may be mixed at the same time or separately. The reaction solution contains the bound halogen produced during the reaction.
In the present embodiment, the concentration of free halogen in the reaction solution can be lowered, while the efficiency of producing bound halogen in the reaction solution can be increased. Since the production efficiency of the bonded halogen is high, the effect caused by the bonded halogen can be efficiently brought out. Further, since free halogen is easily decomposed by an aqueous reducing substance, it is preferable to increase the production efficiency of the bound halogen in order to effectively exert the bound halogen. Therefore, this embodiment is also advantageous from this viewpoint. Has advantages.

In the present embodiment, the reaction solution reacted so that the total residual halogen concentration becomes a predetermined concentration or more is added to the aqueous system. More specifically, the reaction solution is added to aqueous water (for example, water to be treated, circulating water, etc.). When the reaction solution is added to an aqueous system (for example, water to be treated), the free halogen concentration in the aqueous system (for example, water to be treated) is easily set to less than 0.2 mg-Cl ₂ / L as the free chlorine concentration. The free chlorine concentration can be reduced to 0.1 mg-Cl ₂ / L or less, and more preferably 0.05 mg-Cl ₂ / L or less (more preferably 0.01 mg-Cl _2). / L or less) is also possible. Further, it is desirable that free chlorine in the water system (for example, water to be treated) is not detected by the DPD method 5 minutes after the reaction solution is added to the water system (for example, water to be treated).

By adding the reaction solution of the present embodiment to an aqueous system (for example, water to be treated), the free halogen concentration (for example, free chlorine concentration) in the aqueous system (for example, water to be treated) can be significantly reduced. Therefore, when the reverse osmosis membrane treatment of the present embodiment is performed, deterioration of the reverse osmosis membrane to be supplied afterwards can be suppressed, and since the reaction solution of the present embodiment contains bound halogen, the reaction solution is water-based (for example,). , Water to be treated, etc.) can suppress fouling of the reverse osmosis membrane that is subsequently supplied with water. Further, since the free halogen concentration can be significantly reduced in this embodiment as described above, when the reaction solution of this embodiment is added to the water system, the cause is the free halogen in the water system (for example, a water flow pipe or a flow path). Corrosion can be suppressed better. More specifically, by adding the reaction solution of the present embodiment, the corrosion of equipment and devices provided in the water system (more specifically, water flow pipes and flow paths of the equipment and devices) can be improved. It can be suppressed. The corrosion generally refers to the corrosion of a metal, but in the present embodiment, unless otherwise specified, it means to include the deterioration of a resin such as plastic, and more preferably, the suppression of the metal corrosion in the present embodiment. Further, in the reaction solution of the present embodiment, in an aqueous system (for example, a water flow pipe or a flow path), an effect caused by a bonded halogen (for example, an effect of suppressing fouling of a reverse osmosis membrane or other aqueous system) is appropriate. ) Can be exhibited better.

In the present embodiment, the stability is such that the total residual halogen concentration of the reaction solution is at least 100 mg-Cl ₂ / L or more, preferably 125 mg-Cl ₂ / L or more, and more preferably 150 mg-Cl ₂ / L or more. The agent is reacted with the halogen-based oxidizing agent. By adding the reaction solution to an aqueous system (for example, water to be treated), deterioration of the reverse osmosis membrane can be suppressed more satisfactorily. Further, according to the present embodiment, corrosion of the water system can be suppressed more satisfactorily as appropriate. Further, in the present embodiment, the effects caused by the bound halogen (for example, suppression of reverse osmosis membrane fouling, suppression of water-based biofouling, etc.) can be more satisfactorily exhibited.
The upper limit of the total residual halogen concentration of the reaction solution is not particularly limited, but from the viewpoint of the halogen-based oxidizing agent and stabilizer used, the upper limit is about 100,000 mg-Cl ₂ / L.

By reacting the reaction solution so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more, the free halogen ratio (%) can be suppressed to 10% or less of the total residual halogen. As a result, deterioration of the reverse osmosis membrane can be suppressed more appropriately, and corrosion of the water system can be suppressed more appropriately.
Further, by reacting the reaction solution so that the total residual halogen concentration is 150 mg-Cl ₂ / L or more, 95% or more of the total residual halogen in the reaction solution can be made into stabilized bonded chlorine, and the reaction solution can be obtained. The free halogen ratio (%) in the medium can be suppressed to less than 2% of the total residual halogen. Thereby, deterioration of the reverse osmosis membrane can be suppressed more satisfactorily, and corrosion of the water system can be suppressed satisfactorily as appropriate. Further, in the present embodiment, the effects caused by the bound halogen (for example, suppression of reverse osmosis membrane fouling, suppression of water-based biofouling, etc.) can be more satisfactorily exhibited.

In the present embodiment, the free halogen ratio (%) in the reaction solution is preferably 10% or less, more preferably 8% or less, still more preferably 3% or less, and more preferably 2.5% or less of the total residual halogen. , More preferably 2.0% or less, more preferably 1.5% or less, more preferably 1.1% or less. By using a reaction solution having a low free chlorine ratio (%) in an aqueous system (for example, water to be treated), deterioration of the reverse osmosis membrane can be appropriately suppressed, and corrosion of the aqueous system can be appropriately suppressed. Can be suppressed. Further, according to the present embodiment, the effects caused by the bound halogen (for example, suppression of reverse osmosis membrane fouling, suppression of water-based biofouling, etc.) can be more satisfactorily exhibited.

In the present embodiment, the stabilized bound chlorine ratio (%) in the reaction solution is preferably 85% or more, more preferably 87% or more, still more preferably 95% or more, still more preferably 98% of the total residual halogen. Above, more preferably 99% or more. By using the reaction solution having a high stabilized bound chlorine ratio (%) in an aqueous system (for example, water to be treated), deterioration of the reverse osmosis membrane can be appropriately suppressed, and corrosion of the aqueous system can be suppressed more appropriately. it can. Further, according to the present embodiment, the effects caused by the bound halogen (for example, suppression of reverse osmosis membrane fouling, suppression of water-based biofouling, etc.) can be more satisfactorily exhibited.

The total residual halogen concentration, free halogen concentration, and free halogen ratio (%) are measured (calculated) as total chlorine concentration (total residual chlorine concentration), free chlorine concentration, and free chlorine ratio (%), respectively. The residual chlorine concentration, free chlorine concentration, free chlorine ratio (%) and the activated bound chlorine concentration, stabilized bound chlorine concentration and stabilized bound chlorine ratio (%) are described in <Method for measuring total residual chlorine concentration> described later. Can be measured (calculated).

The reaction solution is preferably a mixture of a high concentration stabilizer and a high concentration halogen-based oxidizing agent and reacted so that the total residual chlorine concentration becomes the predetermined concentration. A reaction solution having a predetermined total residual chlorine concentration obtained by mixing the two at a high concentration may be diluted with water before being added to an aqueous system (for example, water to be treated).

Further, in the reaction solution, the total residual chlorine concentration is determined by using a diluted solution obtained by diluting either or both of the stabilizer and the halogen-based oxidizing agent with water and diluting either or both of them with water. Those that have been reacted to a concentration are suitable.
Further, the reaction solution may be prepared by mixing a drug before water dilution and a drug after water dilution, or by mixing a drug after water dilution and a drug after water dilution. Alternatively, it may be prepared by water dilution before adding to an aqueous system (for example, water to be treated).

Examples of the water used for the dilution include desalted water, pure water, ultrapure water and the like. The water is preferably industrial water, well water, tap water, rainwater or the like that has been subjected to impurity removal treatment (for example, ion exchange treatment, membrane treatment, etc.). Of these, desalted water or pure water is preferable from the viewpoint of cost and the effect of the present technology.

The concentration of the active ingredient (preferably the concentration of the sulfamic acid compound) in the stabilizer is not particularly limited, but the lower limit thereof is preferably 10% by mass or more from the viewpoint of further reducing the concentration of free chlorine in the reaction solution. , More preferably 15% by mass or more, still more preferably 20% by mass or more, and the upper limit thereof is about 30% by mass from the viewpoint of solubility.

The effective halogen concentration in the halogen-based oxidizing agent is not particularly limited, but the lower limit thereof is preferably 1% by mass or more, more preferably 5% by mass or more from the viewpoint of being able to further reduce the free halogen concentration in the reaction solution. It is more preferably 10% by mass or more, and the upper limit thereof is preferably about 12% by mass from the viewpoint of solubility, stability and the like.

The amount of the stabilizer used is preferably 1 mol or more, more preferably 1.1 mol or more, with respect to 1 mol of the halogen-based oxidizing agent. The upper limit of the amount of the stabilizer used is preferably 20 mol or less, more preferably 15 mol or less, still more preferably 10 mol or less, relative to 1 mol of the halogen-based oxidizing agent, from the viewpoint of stable reaction and cost. Even more preferably, it is 5 mol or less. The amount of the stabilizer to be used is more preferably 1 to 10 mol, still more preferably 1 to 3 mol, based on 1 mol of the halogen-based oxidizing agent.

In the present embodiment, it is preferable that the stabilizer contains an alkali containing an alkali metal hydroxide and a sulfamic acid compound. It is preferable to use this stabilizer to react with the halogen-based oxidizing agent to obtain a reaction solution having a predetermined total residual halogen concentration, and to add this reaction solution to an aqueous system (for example, water to be treated). ..

The content ratio of the alkali of the stabilizer and the sulfamic acid compound is N / alkali metal (molar ratio), preferably 0.5 to 1.0, and more preferably 0.5 to 0.7. .. The N / alkali metal (molar ratio) corresponds to the number of moles of the above-mentioned sulfamic acid compound and the number of moles of an alkali composed of an alkali metal hydroxide, and here, the alkali contained in the sulfamate. The amount of metal salt is added as alkali.

The pH of the reaction solution is not particularly limited, and is preferably alkaline, more preferably 11 or more, still more preferably 13 or more.

The temperature of the reaction solution is not particularly limited, and the lower limit is preferably −5 ° C. or higher, and the upper limit is preferably 80 ° C. or lower. The temperature range is more preferably 10 to 60 ° C, still more preferably 10 to 40 ° C. The reaction solution used in the present embodiment can generally be carried out at the temperature of the water to be treated in an apparatus for reverse osmosis membrane treatment of the water to be treated, which is an advantage in the present embodiment. The present embodiment is not particularly limited to the device. Further, the reaction solution used in the present embodiment can be used, for example, in a circulating water system device, or can be applied to the temperature conditions of the device to be applied.

In the present embodiment, any component may be used in addition to the stabilizer and the halogen-based oxidizing agent as long as the effects of the present invention are not impaired. For example, an arbitrary component may be mixed with the reaction solution, or an arbitrary component may be mixed with an aqueous system (for example, water to be treated) to which the reaction solution is added. Optional components include, for example, pH regulators, alkaline agents, dispersants, antiscale agents, slime control agents that work by other mechanisms of action, and the like.
Examples of the alkaline agent include alkali metal salts (for example, lithium salt, sodium salt, potassium salt, etc.), alkaline earth metal salts (for example, magnesium salt, calcium salt, etc.) and the like.

<Method of use in water system in this embodiment: (For example, method of reverse osmosis membrane treatment of water to be treated)>
The water system in the present embodiment is not particularly limited, but for example, a water treatment system for treating water to be treated, a water treatment system for producing industrial water and ultrapure water, a water treatment system for collecting and reusing wastewater, and a seawater kettle. It can also be applied to one or more types of water systems selected from the group consisting of water treatment systems for desalinating water, plant cooling water systems, wastewater treatment water systems, steel water systems, paper pulp water systems, cutting oil water systems, etc. is there.

As an example of the present embodiment, in the water system of the present embodiment (more preferably, the water-treated water system), the reaction solution is added to the water to be treated, and the water to be treated is treated with a reverse osmosis membrane. Permeated water (treated water) can be obtained from this water to be treated by reverse osmosis membrane treatment. This makes it possible to produce industrial water and ultrapure water, collect and reuse wastewater, desalinate seawater and brackish water, and the like.

Further, as an example of the present embodiment, in the water system of the present embodiment, the reaction solution can be added to the water system to exert the effect caused by the bound halogen. In addition, the reaction solution of the present embodiment can appropriately suppress water-based biofouling and / or corrosion. In addition, this embodiment can be used in plant cooling water systems, wastewater treatment water systems, steel water systems, pulp and paper water systems, cutting oil water systems, and the like in various factories.
Further, among the water systems, the circulating water system is often operated while being circulated for a long period of time, and is therefore suitable from the viewpoint of reducing corrosion. Further, a circulating cooling water system (preferably an open circulating cooling water system) or the like is more preferable. In this embodiment, from the viewpoint of corrosion suppression, the bonded halogen can be effectively and long-term added to the circulating cooling water system and the like.

In the water system containing the reaction solution of the present embodiment (for example, water to be treated), the free halogen concentration can be suppressed to less than 0.2 mg-Cl ₂ / L as the free chlorine concentration. Further, according to the present embodiment, it is preferable to suppress the free halogen concentration of the aqueous system containing the reaction solution (for example, water to be treated) to 0.1 mg-Cl ₂ / L or less as the free chlorine concentration. Preferably, it can be suppressed to about 0.00 to 0.05 mg-Cl ₂ / L.

In this way, the concentration of free chlorine in the water system (for example, water to be treated) that passes through the reverse osmosis membrane can be reduced as compared with the conventional method (specifically, Comparative Examples 1 and 2 described later). Deterioration of the film can be suppressed more satisfactorily, and corrosion of the water system can be suppressed more satisfactorily as appropriate. Further, since the aqueous system (for example, water to be treated) contains stabilized bound chlorine, fouling of the reverse osmosis membrane can be appropriately suppressed, and the effect caused by the bound halogen is appropriately improved. It can also be demonstrated in. It is also possible to add a reaction solution containing the bound halogen (preferably stabilized bound chlorine) to an aqueous system (for example, water to be treated) and use it in an aqueous system (for example, a water treated aqueous system). .. As a result, the effect of suppressing biofouling in the water system and the bactericidal / algae killing effect can be expected, and examples of the water system include water treatment water systems; circulating water systems such as cooling towers; and process water systems such as pulp and paper production. Be done. Further, the stabilized bound chlorine in the water system (for example, the water to be treated) can be expected to have higher stability than the conventional chloramine T, and can be expected to generate less free chlorine.

The raw water (for example, water to be treated) used in the present embodiment is not particularly limited, and for example, industrial wastewater containing organic substances, seawater / brackish water, fresh water (river water, lake water, etc.), industrial water / city water, etc. Can be mentioned.

Therefore, the water treatment method using the reverse osmosis membrane treatment of the present embodiment is for collecting and reusing high-concentration to low-concentration TOC-containing wastewater discharged in the electronic device manufacturing field, the semiconductor manufacturing field, and various other industrial fields. Water treatment; desalination of seawater and brackish water; production of pure water or ultrapure water from industrial water and city water; it can be effectively applied to water treatment in other fields. Since this embodiment can also suppress the production of free bromine in seawater / brine, which is more likely to deteriorate the reverse osmosis membrane, it is suitable for application to desalination of seawater / brine.
Further, as another aspect of the present embodiment, the method of using the present embodiment for a water system is more preferably applied to a plant cooling water system, a wastewater treatment water system, a steel water system, a paper pulp water system, a cutting oil water system, and the like. A circulating cooling water system is preferable. Thereby, the corrosion of this water system can be suppressed, and the effect caused by the bound halogen in the reaction solution of the present embodiment can be appropriately exerted in the water system.

<Reverse osmosis membrane>
The reverse osmosis membrane (hereinafter, also referred to as “RO membrane”) used in the present embodiment is not particularly limited, and is, for example, polyamide-based, polyethersulfone-based, polysulfone-based, polyimide-based, polyethyleneimine-based, polyethylene oxide-based, and acetic acid. Examples include cellulose type.
Among these, the polyamide-based RO membrane has an advantage that it can be suitably used because it has a high blocking rate of ionic substances and a large flux. In particular, since aromatic polyamide-based RO membranes have low resistance to chlorine, when a halogen-based oxidant is used, a large amount of free chlorine remains and film deterioration is likely to occur. According to this embodiment, the concentration of free chlorine in the water system (for example, water to be treated) can be significantly reduced, and on the other hand, the effect of preventing fouling of the RO membrane can be obtained, so that the treatment capacity is excellent. However, a polyamide-based RO membrane having low salt resistance can be efficiently used.

<Dose and usage of reaction solution>
The reaction solution of the present embodiment is preferably 3 to 100 mg / L, more preferably 5 to 50 mg / L, and further preferably 10 to 40 mg / L in an aqueous system (for example, water to be treated). For example, it is preferable to add it to water to be treated. The amount to be added is preferably water to be treated.

When the reaction solution is added to an aqueous system (for example, water to be treated) in the present embodiment, the stabilized bound chlorine concentration in the aqueous system (for example, water to be treated) is preferably 0.05 mg-Cl as the lower limit value. _It can be adjusted to be ₂ / L or more, more preferably 0.1 mg-Cl ₂ / L or more, and the upper limit value is preferably 20 mg-Cl ₂ / L or less, more preferably 5 mg-Cl ₂ / L or less. Suitable.
When the reaction solution is added to an aqueous system (for example, water to be treated) in the present embodiment, the range of the stabilized bound chlorine concentration in the aqueous system (for example, water to be treated) is preferably 0.5 to 5 mg. -Cl ₂ / L, and more preferably it is preferable to adjust so that _1~2mg-Cl 2 / L. The amount to be added is preferably water to be treated.
Further, in the present embodiment, when the reaction solution is added to an aqueous system (for example, water to be treated), it is preferable to adjust so that free halogen in the aqueous system (for example, water to be treated) is not detected. .. The addition is preferably in the case of water to be treated.

The addition of the reaction solution of the present embodiment is not particularly limited in the case of an aqueous system in which the membrane treatment is performed, as long as it is before the membrane treatment (preferably reverse osmosis membrane treatment) in the aqueous system (see, for example, FIG. 2). The reaction solution is preferably added between the intake of an aqueous system (for example, water to be treated) and the membrane treatment (preferably reverse osmosis membrane treatment). The place where the reaction solution is added may be, for example, an intake port, a coagulation treatment, a solid-liquid separation treatment, a pre-filter treatment, a reverse osmosis membrane treatment, or any of these channels.
The method of adding the reaction solution is not particularly limited, and a method generally used in a water-treated water system can be adopted, as long as both can be mixed, and the water system (for example, water to be treated) is used for the reaction. It may be added to the solution.
As a more specific example, for example, in the present embodiment, the concentration of the bound halogen (preferably stabilized bound chlorine) in the water system (preferably the water to be treated) can be increased, so that the reverse osmosis membrane treatment can be performed. The reaction solution can be added in the vicinity of the upstream side, and the effect caused by the bound halogen can be exerted in the downstream side.

Further, the reaction solution of the present embodiment can be added as a place of addition, for example, the reaction solution can be added near the intake of the water to be treated (see FIG. 2).
Further, as an example, in the present embodiment, since the free chlorine concentration in the water to be treated can be significantly reduced, it can be added immediately before the reverse osmosis membrane treatment. As a result, the concentration of stabilized bound chlorine in the water to be treated immediately before the reverse osmosis membrane treatment can be increased while suppressing the deterioration of the reverse osmosis membrane, so that the biofouling suppressing effect can be efficiently enhanced. In order to obtain this effect, the stabilized bound chlorine concentration in the water to be treated may be adjusted immediately before the reverse osmosis membrane treatment.

When the water system of the present embodiment is a circulating water system, the time or place of adding the reaction solution of the present embodiment is not particularly limited, and the reaction solution can be added at a place where an effect due to the bonded halogen is expected. In the present embodiment, it is preferably applied to an open circulation type device having a cooling water system, a heat storage water system, a dust collecting water system, a scrubber water system, and the like.

Since the present embodiment can have a high concentration of bound halogen (preferably stabilized bound chlorine), microorganisms or microorganisms adhering to the water flow pipe or flow path of the water system are downstream of the addition of the reaction solution of the present embodiment to the water system. It is also possible to prevent the adhesion of organisms (biofouling) and to sterilize and kill algae. In the present embodiment, biofouling of the water system can be suppressed in this way, and in the present embodiment, free halogen can be reduced as much as possible. Therefore, for the purpose of suppressing corrosion, the water system (for example, through) It can also be used for water pipes, flow paths, etc.).

As another aspect of the present embodiment, the use or method of use of the reaction solution of the present embodiment can be provided, and the purpose of use thereof is, for example, an aqueous biofouling suppression method, an aqueous anticorrosion method, or an aqueous system. A method for preventing the film scale of the above can be mentioned. Further, the present embodiment can also provide a water treatment method, a biofouling suppression method, an anticorrosion method, or a scale prevention method by adding the reaction solution of the present embodiment to an aqueous system. A configuration that overlaps with the above configuration will be omitted as appropriate.

<Water treatment equipment>
As another aspect of the present invention, it is also possible to provide the reaction solution production apparatus, a water treatment apparatus provided with the reaction solution production apparatus, and the like. The reaction solution manufacturing apparatus and the water treatment apparatus provided with the reaction solution can carry out the method of the present embodiment described above (preferably a method of treating water to be treated with a reverse osmosis membrane). Permeated water (treated water) can be obtained by the reverse osmosis membrane treatment method. The concentrated water separated from the water to be treated can be returned to the water-treated water system.
Further, the reaction solution production apparatus and the water system apparatus provided with the reaction solution apparatus (preferably a circulating water apparatus) can appropriately exert an effect caused by the bound halogen (for example, suppression of biofouling), and also. Corrosion of the water system (preferably the circulating water system) can be suppressed as appropriate.

The reaction solution manufacturing apparatus according to the embodiment of the present invention
An apparatus for producing a reaction solution containing a bonded halogen is suitable, and the reaction solution producing apparatus is used.
A generator that reacts a stabilizer and a halogen-based oxidant to produce a reaction solution containing a bound halogen.
A control unit that adjusts the stabilizer and halogen-based oxidant so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration in the reaction solution.
A device having the above is more preferable.
The reaction solution is preferably a reaction solution for suppressing fouling of a reverse osmosis membrane or a reaction solution for suppressing biofouling of an aqueous system.

The water treatment apparatus according to the embodiment of the present invention
A generator that produces a reaction solution containing a bound halogen produced by reacting a stabilizer and a halogen-based oxidant,
The reaction solution contains a control unit that adjusts the stabilizer and halogen-based oxidant so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration.
A reverse osmosis membrane treatment unit for reverse osmosis membrane treatment of an aqueous system (preferably water to be treated) to which a reaction solution having a total residual halogen concentration of 100 mg-Cl ₂ / L or more as a total chlorine concentration is added.
A device having the above is suitable.

An example of the present embodiment will be shown and the present invention will be described with reference to FIG. 2, but the present embodiment is not limited thereto.

The control unit 6 can adjust the composition of the stabilizer and the halogen-based oxidizing agent so that the total residual halogen concentration in the reaction solution described above is reached. The control unit 6 can obtain a measured value (data) of the total residual halogen concentration in the reaction solution from the reaction solution mixing unit 9 that reacts the stabilizer with the halogen-based oxidizing agent. Further, the control unit 6 can obtain a measured value (data) of the MF film processing unit and / or the RO membrane processing unit, and the total residual halogen concentration immediately before or after these. As an apparatus (not shown) for measuring the total residual halogen concentration, a known measuring apparatus may be used. Alternatively, the reaction solution or an aqueous system (for example, water to be treated) may be sampled from the reaction solution mixing unit 9, the total residual halogen concentration may be measured, and the measurement result may be input to the control unit 6.

Based on the measured value of the total residual halogen concentration, the control unit 6 adds a stabilizer and an amount of the halogen-based oxidizing agent so as to obtain the predetermined total residual halogen concentration described above. It is possible to instruct the part 7 and the halogen-based oxidant addition part 8. As a result, the stabilizer is added to the reaction solution mixing section 9 from the stabilizer adding section 7, and the halogen-based oxidizing agent is added to the reaction solution mixing section 9 from the halogen-based oxidizing agent adding section 8.

The control unit 6 can adjust by adding water for dilution to a stabilizer, a halogen-based oxidizing agent, or a mixed agent thereof, if necessary.
The control unit 6 can instruct a pump, a reaction solution addition unit (not shown), or the like to add the reaction solution to an aqueous system (for example, water to be treated) from the reaction solution mixing unit 9. The addition location may be any location from the reverse osmosis membrane treatment unit 2 to the intake port of the water system (for example, water to be treated). Further, the control unit 6 can also control the addition amount, addition timing, stirring and the like of the reaction solution to the water system (for example, water to be treated). In addition, the control unit 6 can adjust the amount of the stabilizer added and the amount of the halogen-based oxidizing agent added so that the concentration in the system after the addition of the reaction solution becomes a predetermined value. Further, the control unit 6 can be adjusted so that the reaction solution is continuously or discontinuously (intermittently) added to the water system (for example, water to be treated).

The method of the present embodiment is realized by a control unit including a CPU in an apparatus for producing the reaction solution or an apparatus for performing reverse osmosis membrane treatment of water to be treated (for example, a personal computer, PLC, etc.). It is also possible. Further, the method of the present embodiment may be stored as a program in a hardware resource including a recording medium (nonvolatile memory (USB memory or the like), HDD, CD, network, server, etc.) and realized by the control unit. It is possible.
A system for producing the reaction solution, or a reverse osmosis membrane separation treatment system or an aqueous system (for example, water treatment) for controlling the reaction solution to be produced and added to an aqueous system (for example, water to be treated) by the control unit. It is also possible to provide systems (systems, circulating water systems, etc.).
When the present embodiment is applied to a water system or a circulating water system, the method of the present embodiment can be executed by incorporating the manufacturing apparatus of the present embodiment into a normal water treatment device or a circulating water device. ..

The reaction solution manufacturing apparatus in this embodiment preferably includes a reaction solution generation unit 10 and a control unit 6.
The reaction solution generation unit 10 mixes the stabilizer addition unit 7 and the halogen-based oxidant addition unit 8, and the stabilizer and the halogen-based oxidant to prepare the reaction solution so that the total residual halogen concentration becomes a predetermined concentration. It is preferable to include the reaction solution mixing unit 9 to be produced.
The reaction solution generation unit 10 may control the stabilizer addition unit 7, the halogen-based oxidant addition unit 8, and the reaction solution mixing unit 9 by a command from the control unit 6. Further, the reaction solution generation unit 10 may have a second control unit that receives a command from the control unit 6, and the second control unit may provide a stabilizer addition unit 7 and a halogen-based oxidant addition unit. 8 and the reaction solution mixing unit 9 may be controlled.

Further, the stabilizer adding section 7 and the halogen-based oxidizing agent adding section 8 may be a tank capable of storing the stabilizer and the halogen-based oxidizing agent, respectively, or in a flow path such as a water flow pipe. There may be. Each addition amount and each transfer amount of these chemicals and diluted water can be adjusted by a pump, a flow rate adjusting valve, or the like.
Further, the reaction solution mixing unit 9 may have a place where a stabilizer and a halogen-based oxidizing agent can be mixed, and examples thereof include a flow path such as a water flow pipe and a tank. Further, it is preferable that the reaction solution mixing unit 9 is provided with a mixing device such as stirring. The amount of these chemicals, reaction solution, diluted water, etc. added and transferred can be adjusted with a pump, a flow rate adjusting valve, or the like.

As another embodiment of the present embodiment, a pump is provided at each discharge port of the stabilizer addition section 7 and the halogen-based oxidant addition section 8, the reaction solution mixture 9 is used as a mixing line, and a catch valve is provided at the inlet of the mixing line. Be prepared. It is preferable that the mixing line is provided with a device capable of mixing both drugs, and examples thereof include a static mixer.
According to the command of the control unit 10, the stabilizer and the halogen-based oxidant are transferred from the pump discharge ports of the stabilizer addition unit 7 and the halogen-based oxidant addition unit 8 to the mixing line. According to the command of the control unit 10, the flow rates of both are adjusted by the catch valve so that the total residual halogen concentration becomes equal to or higher than a predetermined value. The two are reacted in a mixing line where the two meet to produce a reaction solution containing a bound halogen when the total residual halogen concentration is equal to or higher than a predetermined value. Then, the reaction solution is added to an aqueous system (for example, water to be treated), and the aqueous system (for example, water to be treated) is treated with a reverse osmosis membrane. Thereby, permeated water can be obtained. By using the reaction solution, it is possible to suppress the fouling of the reverse osmosis membrane while suppressing the deterioration of the reverse osmosis membrane. Furthermore, by using the reaction solution, an aqueous biofouling inhibitory effect can be appropriately obtained. The biofilm and slime are produced by microorganisms (bacteria, algae, etc.).

The apparatus or system of the present embodiment allows a reaction solution in which the free halogen of the present embodiment is significantly reduced and contains a bound halogen to be added to an aqueous system (for example, water to be treated), whereby a reverse osmosis membrane can be added. It is possible to obtain the effect of suppressing fouling of the reverse osmosis membrane and the effect of suppressing slime in the water system while suppressing the deterioration of the water system.
Further, examples of the water treatment system according to the present embodiment include a pure water production system, a seawater desalination system, and a wastewater treatment system. Further, the water system device according to the present embodiment is not particularly limited, and may be a water treatment system device such as a pure water production device or a seawater desalination device having these exemplary systems, and a circulating water system such as a circulating cooling water device. It may be a device having.

In addition, the present technology can also adopt the following configurations.
[1] A reaction solution obtained by reacting a stabilizer and a halogen-based oxidizing agent so that the total residual halogen concentration becomes 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate a bound halogen is added to the water to be treated. A method of treating the water to be treated with a reverse osmosis membrane.
[2] A reaction solution obtained by reacting a stabilizer and a halogen-based oxidizing agent so that the total residual halogen concentration becomes 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate a bound halogen is added to the aqueous system. A method for suppressing biofouling in the water system.
[3]
The method according to the above [1] or [2], wherein the stabilizer is a sulfamic acid compound.
[4]
The method according to the above [1] to [3], wherein the stabilizer reacts with 1 mol of the halogen-based oxidizing agent in an amount of 1 mol or more.
[5]
The method according to any one of [1] to [4] above, wherein the free halogen ratio (%) in the reaction solution is 10% or less of the total residual halogen.
[6]
The method according to any one of [1] to [5] above, wherein the total residual halogen concentration is 125 mg-Cl ₂ / L or more.

[6]
A device for producing reaction solutions containing bonded halogens.
A generator that reacts a stabilizer and a halogen-based oxidant to produce a reaction solution containing a bound halogen.
A control unit that adjusts the stabilizer and halogen-based oxidant so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration in the reaction solution.
Manufacturing equipment with.
[7]
The production apparatus according to the above [6], wherein the reaction solution containing the bound halogen is a reaction solution for suppressing fouling of a reverse osmosis membrane or a reaction solution for suppressing biofouling of an aqueous system. The manufacturing apparatus is preferably applied to a reverse osmosis membrane treatment apparatus or a circulating cooling water apparatus.
[8]
The production apparatus according to any one of [6] and [7] above, wherein the stabilizer is a sulfamic acid compound.
[9]
The production apparatus according to any one of [6] to [8], wherein the stabilizer reacts with 1 mol of the halogen-based oxidizing agent at 1 mol or more.
[10]
The manufacturing apparatus according to any one of [6] to [9] above, wherein the free halogen ratio (%) in the reaction solution is 10% or less of the total residual halogen.
[11]
The manufacturing apparatus according to any one of [6] to [10] above, wherein the total residual halogen concentration is 125 mg-Cl ₂ / L or more.

An embodiment of the present invention will be described with reference to the following examples and comparative examples. The scope of the present invention is not limited to the examples.

[Example 1: Free chlorine concentration in water to be treated]
The bonding state of chlorine when the oxidizing agent and the stabilizer were mixed in advance and then added into the system was evaluated on a desk.
<Procedure>
A sodium sulfamic acid solution having a sulfamic acid concentration of 20% or more was prepared. Sodium hypochlorite having an effective chlorine concentration of 10% or more was added thereto. The mixing ratio was 3 mg / L or more as sulfamic acid with respect to a 1 mg-Cl ₂ / L solution of sodium hypochlorite.
As a result, a reaction solution containing a stabilizer and a chlorine-based oxidizing agent was prepared. The total residual chlorine concentration of the reaction solution containing the stabilizer and the chlorine-based oxidizing agent was 100 mg-Cl ₂ / L or more. Then, a 500 mg / L NaCl solution was used as the water to be treated.
The above reaction solution 5 minutes after preparation was added to a 500 mg / L NaCl solution so that the concentration was 20 mg / L. The residual chlorine concentration 5 minutes and 60 minutes after the addition of sulfamic acid was measured by the DPD method.

<Calculation method of total residual chlorine concentration>
The total residual chlorine concentration was calculated based on the following method.
Total residual chlorine concentration = free chlorine concentration + activated combined chlorine concentration + stabilized combined chlorine concentration.
Free chlorine concentration: Free chlorine concentration by the DPD method (Pocket Residual Chlorine Meter, manufactured by HACH) [Here, the free chlorine concentration by the DPD method is 5 to 30 seconds after the DPD (Free) reagent, which is a reagent for measuring free chlorine. Chlorine concentration measurement result (mg-Cl ₂ / L)].
Activation-bound chlorine concentration: From the chlorine concentration measurement result (mg-Cl ₂ / L) after 300 seconds using the DPD (Free) reagent, which is a reagent for measuring free chlorine, the free chlorine concentration (mg-Cl ₂ / L) Value after subtracting the measurement result.
Stabilized bound chlorine concentration: From the chlorine concentration measurement result (mg-Cl ₂ / L) after 180 seconds with the DPD (Total) reagent, which is a reagent for measuring total chlorine, it depends on the DPD (Free) reagent, which is a reagent for measuring free chlorine. The value obtained by subtracting the chlorine concentration measurement result (mg-Cl ₂ / L) after 300 seconds.
Free chlorine ratio (%) = (free chlorine concentration / total residual chlorine concentration) x 100
Stabilized bound chlorine ratio (%) = (Stabilized bound chlorine concentration / total residual chlorine concentration) x 100
The temperature of the test environment was 25 ° C.

<Results / Discussion>
[Results of residual chlorine concentration immediately after the addition of the drug (reaction solution) to the water to be treated (water to be treated after the addition of the reaction solution)]
・ Free chlorine concentration = 0.01mg-Cl ₂ / L
・ Activation-bound chlorine concentration = 0.00 mg-Cl ₂ / L
-Stabilized bound chlorine concentration = 1.26 mg-Cl ₂ / L

Since the stabilizer and the chlorine-based oxidizing agent were reacted at high concentrations, free chlorine in the reaction solution was no longer detected after a reaction time of 5 minutes.
From this, if a reaction solution containing stabilized bonded chlorine generated by reacting a stabilizer and a chlorine-based oxidant so that the total residual chlorine concentration becomes 100 mg-Cl ₂ / L or more is used, a short time is required. Residual chlorine will not be detected.
Therefore, since the residual chlorine of the reaction solution of the present invention has sufficiently reached a level that does not deteriorate the reverse osmosis membrane, the reaction solution can suppress the deterioration of the reverse osmosis membrane. Furthermore, since the reaction solution contains stabilized bound chlorine, it is possible to suppress slime in the reverse osmosis membrane system and prevent fouling of the reverse osmosis membrane.

Further, a reaction solution containing a stabilizer and a chlorine-based oxidizing agent was prepared so that the total residual chlorine concentration was 48,000 mg / L or more. This reaction solution was added to a 500 mg / L NaCl solution (water to be treated) at water temperatures of 5 ° C., 20 ° C., 40 ° C., and 50 ° C. and mixed. As for the free chlorine concentration in the 500 mg / L NaCl solution at each water temperature to which the reaction solution was added, free chlorine was not detected within 30 seconds.
From this, even at the water temperature normally treated by the reverse osmosis membrane treatment apparatus, residual chlorine is not detected in a short time by using the reaction solution as in Example 1. Therefore, the reaction solution of the present invention can be used without any problem at a water temperature that is usually treated with a reverse osmosis membrane.

[Comparative Examples 1 and 2]
The chlorine binding state when the oxidizing agent and the stabilizer were added separately into the system was evaluated on the desk.
<Procedure>
A 500 mg / L NaCl solution was prepared as water to be treated in a beaker.
Instead of using a mixed solution in which a stabilizer and a chlorine-based oxidant are mixed in advance as in [Example 1] above, each of them is separately added to the NaCl solution to add the stabilizer and the chlorine-based oxidant. The total residual chlorine concentration and sulfamic acid concentration were adjusted while adding to the NaCl solution.
To the above NaCl solution, a sodium hypochlorite solution and a sodium sulfamic acid solution were separately added in this order so that the total residual chlorine concentration was 1 mg-Cl ₂ / L and the sulfamic acid concentration was 3 mg / L or more.
The residual chlorine concentration 5 minutes and 60 minutes after the addition of sulfamic acid was measured by the DPD method (the calculation method is the same as in Example 1).
The temperature of the test environment was 25 ° C.

<Results / Discussion>
[Comparative Example 1: Water to be treated with chlorine-based oxidizing agent added and then sulfamic acid added]
(1) Residual chlorine concentration result "5 minutes after addition of sulfamic acid" to the water to be treated with chlorine-based oxidant-Free chlorine concentration = 0.20 mg-Cl ₂ / L
-Activation-bound chlorine concentration = 0.47 mg-Cl ₂ / L
・ Stabilized combined chlorine concentration = 0.37 mg-Cl ₂ / L
(2) Residual chlorine concentration result "60 minutes after addition of sulfamic acid" to the water to be treated with chlorine-based oxidant-Free chlorine concentration = 0.20 mg-Cl ₂ / L
-Activation-bound chlorine concentration = 0.29 mg-Cl ₂ / L
-Stabilized bound chlorine concentration = 0.53 mg-Cl ₂ / L

[Comparative Example 2: Water to be treated with chlorine-based oxidant added and then high-concentration sulfamic acid added]
Results of residual chlorine concentration when "sulfamic acid 27 mg / L", which is one order higher than the sulfamic acid concentration, was added (after 60 minutes)
-Free chlorine concentration = 0.19 mg-Cl ₂ / L
-Activation-bound chlorine concentration = 0.28 mg-Cl ₂ / L
-Stabilized bound chlorine concentration = 0.55 mg-Cl ₂ / L

From the above results, in Comparative Example 1, about 0.2 mg-Cl ₂ / L of free chlorine remained, and there was a risk of deteriorating the RO film. It does not decrease completely with the passage of time, and it is difficult to reduce free chlorine by reacting a stabilizer in the system. Even if the concentration of sulfamic acid was significantly increased, the effect was limited.

[Example 2: Total residual chlorine concentration of reaction solution]
Chlorine when the total residual chlorine concentration when mixing the oxidant-based agent and its stabilizer is changed in the reaction solution containing the stabilized bonded chlorine generated by reacting the stabilizer and the chlorine-based oxidant. The combined state of was evaluated on the desk.
<Procedure>
Pure water was prepared in a beaker. The temperature of the test environment was 25 ° C. A sodium sulfamic acid solution prepared so that the sulfamic acid concentration was 20% or more was added to pure water. Sodium hypochlorite having an effective chlorine concentration of 10% or more was added to the aqueous solution containing sulfamic acid. The mixing ratio was adjusted so that the amount of sulfamic acid was 3 mg / L or more with respect to the 1 mg / L solution of sodium hypochlorite. As a result, a reaction solution containing a stabilizer and a chlorine-based oxidizing agent was prepared.
The residual chlorine concentration after mixing the prepared reaction solution for 30 seconds was measured by the DPD method (the calculation method is the same as in Example 1). This operation was repeated while changing the amount of pure water. As a result, the chlorine binding state at the time of dilution and mixing was adjusted, and reaction solutions containing stabilizers and chlorine-based oxidizing agents having different total residual chlorine concentrations were prepared (see Table 1 and FIG. 1).

<Result>
Table 1 and FIG. 1 show the results of summarizing the abundance ratios of stabilized bound chlorine and free chlorine in the total residual chlorine for each total residual chlorine concentration after mixing. Only the low concentration side is shown in FIG.
From the results, if the total residual chlorine concentration after mixing is 100 mg-Cl ₂ / L or more, free chlorine can be suppressed to within 10% of the total residual chlorine.
Therefore, when either or both of sodium hypochlorite and the stabilizer are diluted and used, the total residual chlorine concentration after mixing needs to be 100 mg-Cl ₂ / L or more, preferably 100 mg-Cl ₂ / L or more. It is desirable that it is 125 mg-Cl ₂ / L or more, more preferably 150 mg-Cl ₂ / L or more.
When the reaction solution of Example 2 was added to the water to be treated 5 minutes after preparation so that the concentration was 20 mg / L, the free chlorine concentration was 0.00 to 0.05 mg / L. It is about L.

From this, if a reaction solution containing stabilized bonded chlorine generated by reacting a stabilizer and a chlorine-based oxidant so that the total residual chlorine concentration becomes 100 mg-Cl ₂ / L or more is used, a short time is required. Residual chlorine will not be detected.
Therefore, since the residual chlorine of the reaction solution of the present invention has sufficiently reached a level that does not deteriorate the reverse osmosis membrane, the reaction solution can suppress the deterioration of the reverse osmosis membrane. Furthermore, since the reaction solution contains stabilized bound chlorine, it is possible to suppress slime in the reverse osmosis membrane system and prevent fouling of the reverse osmosis membrane.

[Example 3: Ratio of stabilizer used]
The chlorine binding state when the mixing ratio of the oxidizing agent and the stabilizer was changed was evaluated on the desk.
<Procedure>
Pure water was prepared in a beaker. The temperature of the test environment was 25 ° C. A sodium sulfamic acid solution prepared so that the sulfamic acid concentration was 20% or more was added to pure water. Sodium hypochlorite having an effective chlorine concentration of 10% or more was added to the aqueous solution containing sulfamic acid. As a result, a reaction solution containing a stabilizer and a chlorine-based oxidizing agent was prepared.
The residual chlorine concentration after mixing the prepared reaction solution for 30 seconds was measured by the DPD method (the calculation method is the same as in Example 1). This operation was repeated at the same residual chlorine concentration (450 mg-Cl ₂ / L) while changing the amount of sulfamic acid. As a result, the chlorine state when the usage ratio of the chlorine-based oxidant and the stabilizer is changed is adjusted, and the usage ratio of the chlorine-based oxidant and the stabilizer in the reaction solution containing the stabilizer and the chlorine-based oxidant is different. A solution was prepared (see Table 2).

<Result>
Table 2 shows the amount [mol] of sulfamic acid added to 1 mol of hypochlorous acid. From the results, if 1.1 mol or more of sulfamic acid is added to 1 mol of hypochlorous acid, 95% or more of the total residual chlorine becomes stabilized bonded chlorine, and free chlorine is 2.0% of the water to be treated. It can be seen that it can be suppressed to less than.
Therefore, even when the amount of stabilizer added is small with respect to sodium hypochlorite, if sulfamic acid is added 1.1 mol times or more with respect to hypochlorous acid, almost the entire amount is added. A stable component that has become stabilized bound chlorine can be obtained.

From this, when a reaction solution containing stabilized bonded chlorine produced by reacting a stabilizer and a chlorine-based oxidant so that the total residual chlorine concentration becomes 100 mg-Cl ₂ / L or more is prepared, it is stable. It is more preferable that the ratio of the agent and the chlorine-based oxidant to be used is 1.1 mol times or more the stabilizer and 1 mol of the chlorine-based oxidant.
As a result, the reaction solution of the present invention can better suppress the deterioration of the reverse osmosis membrane. In addition, the reaction solution can better contain stabilized bound chlorine, thus suppressing slime in the reverse osmosis membrane system and better preventing fouling of the reverse osmosis membrane.

1 Water-treated water system; 2 RO membrane treatment unit (RO membrane treatment); 3 Aggregation treatment unit (aggregation treatment); 4 Solid-liquid separation treatment unit (solid-liquid separation treatment); 5 MF membrane treatment unit (prefilter treatment); 6 Control unit; 7 Stabilizer addition unit; 8 Halogen-based oxidizer addition unit; 9 Reaction solution mixing unit; 10 Reaction solution generation unit

Claims (8)

In an aqueous system, before adding to the water to be treated, a stabilizer and a halogen-based oxidizing agent were reacted so that the total residual halogen concentration was 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate bound halogen. Produce a reaction solution ,
The reaction solution is added to the water to be treated so that the stabilized bound chlorine concentration is in the range of 0.05 mg-Cl ₂ / L or more and 20 mg-Cl ₂ / L or less in the water to be treated, and the water to be treated is reverse osmotic. It is a method of membrane treatment,
The stabilizer is a sulfamic acid compound,
The reaction solution is obtained by reacting the stabilizer with 1 mol of the halogen-based oxidizing agent in an amount of 1 mol or more.
The reaction solution, total residual halogen concentration is of _100mg-Cl 2 / L or more _100000mg-Cl 2 / L or less as total chlorine concentration, free halogen ratio of the reaction solution (%) is the total residual halogen 10% or less,
The reverse osmosis membrane treatment method . The reverse osmosis membrane treatment method according to claim 1 , wherein the stabilized bound chlorine ratio (%) in the reaction solution is 85% or more of the total residual halogen . Free halogen concentration is 0.2mg-Cl as free chlorine concentration ₂ The reverse osmosis membrane treatment method according to claim 1 or 2, wherein the water to be treated with less than / L is treated with a reverse osmosis membrane. The reverse osmosis membrane treatment method according to any one of claims 1 to 3 , wherein the total residual halogen concentration is 125 mg-Cl ₂ / L or more. A device for producing a reaction solution containing a bonded halogen in an aqueous system .
Before adding to the water to be treated, a stabilizer and a halogen-based oxidizing agent are reacted so that the total residual halogen concentration is 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate a reaction solution containing bound halogen. has a reaction solution generating unit,
The stabilizer is a sulfamic acid compound,
The reaction solution is obtained by reacting the stabilizer with 1 mol of the halogen-based oxidizing agent in an amount of 1 mol or more.
The reaction solution, total residual halogen concentration is one 100 _mg-Cl 2 / L or more _100000-Cl in 2 / L or less as total chlorine concentration, free halogen Ratio (%) 10 total residual halogen of the reaction solution % Or less
The reaction solution is added to the water to be treated so that the stabilized bound chlorine concentration is in the range of 0.05 mg-Cl ₂ / L or more and 20 mg-Cl ₂ / L or less in the water to be treated.
The manufacturing equipment. An apparatus for producing a reaction solution containing the bonded halogen according to claim 5.
The stabilizer is reacted with 1 mol of the halogen-based oxidant at 1 mol or more, and the total residual halogen concentration of the stabilizer and the halogen-based oxidant is 100 mg-Cl as the total chlorine concentration. ₂ Prepare the reaction solution so that it is / L or more, and
Stabilizing the reaction solution The combined chlorine concentration is 0.05 mg-Cl in the water to be treated. ₂ / L or more 20 mg-Cl ₂ It has a control unit that controls addition to the water to be treated so as to be in the range of / L or less.
The manufacturing equipment. The production apparatus according to claim 5 or 6, wherein the reaction solution containing the bonded halogen is a reaction solution for suppressing fouling of a reverse osmosis membrane or a reaction solution for suppressing biofouling of an aqueous system. In an aqueous system, before adding to the water to be treated, a stabilizer and a halogen-based oxidizing agent were reacted so that the total residual halogen concentration was 100 mg-Cl ₂ / L or more as the total chlorine concentration to generate bound halogen. Produce a reaction solution ,
A method of suppressing biofouling in an aqueous system by adding the reaction solution to the aqueous system so that the stabilized bound chlorine concentration is in the range of 0.05 mg-Cl ₂ / L or more and 20 mg-Cl ₂ / L or less in the water to be treated. And
The stabilizer is a sulfamic acid compound,
The reaction solution is obtained by reacting the stabilizer with 1 mol of the halogen-based oxidizing agent in an amount of 1 mol or more.
The reaction solution, total residual halogen concentration is of _100mg-Cl 2 / L or more _100000mg-Cl 2 / L or less as total chlorine concentration, free halogen ratio of the reaction solution (%) is the total residual halogen 10% or less,
A method for suppressing biofouling in an aqueous system.