JP6649697B2 - Water sterilization method - Google Patents

Description

  The present invention relates to a method for disinfecting water such as wastewater containing a large amount of ammonia nitrogen and organic substances, and particularly to a method for disinfecting sewage and the like.

  When discharging industrial wastewater and sewage treatment water, including industrial wastewater, into public water bodies, these discharged waters are subject to drainage standards according to the Water Pollution Control Law. In addition, Tokyo Bay, Ise Bay, and the Seto Inland Sea are subject to COD, nitrogen, and phosphorus.

  Of the wastewater, for example, sewage, it is necessary to sterilize the bacterium so that the number of coliform bacteria is 3,000 / mL or less before release, in addition to ammonia nitrogen and organic matter (COD) in order to comply with the wastewater standard and the total amount regulation. It is desirable to reduce the content of components subject to drainage regulations such as component) as much as possible.

  Further, in the sewage treatment, particularly in rainy weather, part of the sewage is discharged into a public water area without treatment, and there is a possibility that the environment of the discharge destination may be deteriorated. Therefore, there is a need for a method of disinfecting water that can reduce the number of coliform bacteria in a short time.

  Chlorine oxidants such as sodium hypochlorite, calcium hypochlorite, liquefied chlorine, and chlorinated isocyanuric acid used as disinfectants are disinfectants for household disinfectants and industrial wastewater including industrial wastewater. It is used in various sterilization applications. On the other hand, in the sterilization of sewage or the like containing a large amount of ammonia nitrogen, particularly when it is rainy, when a part of the sewage is discharged into a public water area without treatment, sterilization in a short time of about 5 minutes is required. . However, the chlorine-based oxidizing agent reacts with ammonia nitrogen contained in the sewage to form chloramine, and the sterilization performance is significantly reduced. Chloramine has a high persistence in the environment. Although chloramine has low sterilizing performance of coliform bacteria, it may remain in public waters as residual chlorine for a long time and adversely affect the environment, so sewage treatment, especially sterilization treatment in rainy weather There is a demand for a disinfectant to replace the chlorine-based oxidant.

  In addition, hypochlorite and bromide, for example, sodium hypobromite produced by mixing sodium hypochlorite and sodium bromide in equimolar amounts, wastewater containing a large amount of ammonia nitrogen, especially as a sterilization application for sewage Can be used. Unlike hypochlorite, hypobromite does not generate bound residual chlorine such as chloramine, so that the influence on aquatic organisms to be discharged can be reduced, and environmental problems hardly occur. However, storage stability of hypobromite is significantly lower than that of hypochlorite. Therefore, it is necessary to add, for example, sodium hypochlorite and sodium bromide immediately before mixing.

JP-A-2003-012425

  An object of the present invention is to provide a method for disinfecting water, which can reduce the number of coliform bacteria in a short time.

The present invention is a method for disinfecting water, in which a chlorine-based oxidizing agent and a stabilized hypobromous acid composition are added to water containing at least 20 mg / L of ammoniacal nitrogen, wherein the stabilized hypobromite is added. acid composition is a reaction product of bromine-based oxidizing agent, or a bromine compound and a chlorine-based oxidizing agent, wherein the sulfamic acid compound, wherein the chlorine-based oxidizing agent, Ri hypochlorous acid or a salt thereof der, The ratio (b / a) of the total chlorine equivalent addition concentration (b) of the stabilized hypobromous acid composition to the total chlorine equivalent addition concentration (a) of the chlorine-based oxidizing agent is 0.11 to 9%. 00 area by der, and is a method of sterilizing water.

The present invention is a method for disinfecting water, in which a chlorine-based oxidizing agent and a stabilized hypobromous acid composition are added to water containing at least 20 mg / L of ammoniacal nitrogen, wherein the stabilized hypobromite is added. The acid composition contains a reaction product of a bromine-based oxidizing agent, or a reaction product of a bromine compound and a chlorine-based oxidizing agent, and a sulfamic acid compound, wherein the chlorine-based oxidizing agent is hypochlorous acid or a salt thereof. der is, the ratio of the added concentration of total chlorine conversion of the stabilizing hypobromite composition for addition concentration of total chlorine conversion (a) of the chlorine-based oxidizing agent (b) (b / a) is 0. area by der of 11 to 9.00, which is a method of sterilizing water.

The present invention is a method for disinfecting water, in which a chlorine-based oxidizing agent and a stabilized hypobromous acid composition are added to water containing at least 20 mg / L of ammoniacal nitrogen, wherein the stabilized hypobromite is added. acid composition comprises the reaction product of a brominated and sulfamic acid compound, the chlorine-based oxidizing agent is hypochlorous acid or a salt thereof, sterilizing method der water is, the chlorine-based oxidizing agent all the ratio of the concentration of the added total chlorine conversion of the stabilizing hypobromous acid composition to the addition concentration of chlorine conversion (a) (b) (b / a) is, area by der of 0.11 to 9.00.

In the sterilization method of the water, the addition concentration of total chlorine conversion of the chlorine-based oxidizing agent (a) concentration of the added total chlorine conversion of the stabilizing hypobromite composition for _{(mg / L as Cl 2)} (b) (mg / L as Cl ₂₎ the ratio of (b / a) is more preferably in the range of 0.11 to 0.67.

  In the method for sterilizing water, it is preferable that the chlorine-based oxidizing agent is added to the water after the stabilized hypobromite composition is added.

  According to the present invention, it is possible to provide a method for disinfecting water in which an effect of reducing the number of coliform bacteria is obtained in a short time.

  An embodiment of the present invention will be described below. The present embodiment is an example for implementing the present invention, and the present invention is not limited to the present embodiment.

<Water sterilization method>
The method of disinfecting water according to the embodiment of the present invention is a method of adding, to water, a “chlorine-based oxidant”, a mixture of a “bromine-based oxidant” and a “sulfamic acid compound”, or This is a method of adding an "oxidizing agent", a "reaction product of a bromine compound and a chlorine-based oxidizing agent", and a mixture of "sulfamic acid compound", respectively. When a stabilized hypobromite composition is formed by a mixture of "brominated oxidizing agent" and "sulfamic acid compound" or a mixture of "reacted product of bromine compound and chlorine oxidizing agent" and "sulfamic acid compound" Conceivable.

  The method of disinfecting water according to the embodiment of the present invention comprises, in water, a `` chlorine oxidizing agent '' and a stabilized hypobromous acid composition that is a `` reaction product of a brominated oxidizing agent and a sulfamic acid compound ''. Or a stabilized hypobromous acid composition which is a "chlorine oxidant" and a "reaction product of a bromine compound and a chlorine oxidant, and a sulfamic acid compound." Is a method of adding each.

  The method for disinfecting water according to the present embodiment includes the steps of: adding "chlorine oxidizing agent" to water; for example, "a reaction product of bromine and a sulfamic acid compound"; and "a reaction product of bromine chloride and a sulfamic acid compound". Or a stabilized hypobromous acid composition which is a "reaction product of sodium bromide and hypochlorous acid with a sulfamic acid compound".

  By these methods, the effect of reducing the number of coliform bacteria can be obtained in a short time. For example, the number of coliforms can be sterilized to 3000 (pieces / mL) or less within 5 minutes.

  In the water disinfection method according to the present embodiment, for example, in water, "chlorine oxidizer", "reaction product of bromine oxidizer and sulfamic acid compound", or "bromine compound and chlorine oxidizer And a reaction product of the sulfamic acid compound ”may be respectively injected by a chemical injection pump or the like.

  The chlorine-based oxidizing agent and the stabilized hypobromite composition may be simultaneously added to water, or the chlorine-based oxidizing agent may be added after the stabilized hypobromite composition is added to water. Alternatively, the stabilized hypobromite composition may be added after the chlorine-based oxidizing agent is added to water. Since the effect of reducing the number of coliform bacteria is high, it is preferable to add the chlorine-based oxidizing agent after adding the stabilized hypobromous acid composition to water. For example, after the stabilized hypobromite composition is added to water, a chlorine-based oxidizing agent may be added after a lapse of a predetermined time, for example, after 5 seconds to 15 minutes. Further, the stabilized hypobromite composition may be added upstream of the aqueous system to be treated, and the chlorine-based oxidizing agent may be added downstream. By adding the stabilized hypobromite composition first, the chlorine-based oxidizing agent reacts with the stabilized hypobromite composition before reacting with the ammoniacal nitrogen contained in the water to form chloramine. It is presumed to show a synergistic effect.

  The ratio of the equivalent of “sulfamic acid compound” to the equivalent of “bromine oxidant” or “reactant of bromine compound and chlorine oxidant” is preferably 1 or more, and more preferably 1 or more and 2 or less. Is more preferable. If the ratio of the equivalent of the “sulfamic acid compound” to the equivalent of the “bromine oxidant” or the “reactant of the bromine compound and the chlorine oxidant” is less than 1, bromate ( (Reference value 0.01 mg / L or less) may occur.

Addition concentration (b) (mg / L as) of “stabilized hypobromite composition” with respect to addition concentration (a) (mg / L as Cl ₂ ) of total amount of “chlorine oxidizing agent” in terms of total chlorine. The ratio (b / a) of Cl ₂ ) is preferably in the range of 0.11 to 9.00, and more preferably in the range of 0.11 to 0.67. If the ratio (b / a) is less than 0.11, the bactericidal effect of the coliform group may be reduced, and if it exceeds 9.00, the bactericidal effect of the coliform group may be reduced.

The “concentration in terms of total chlorine” of the “chlorine-based oxidizing agent” and the “stabilized hypobromite composition” means that the sample was appropriately diluted, and HACH was used for the HACH multi-item water quality analyzer DR / 4000. a total chlorine measuring method PROGRAM 1450 (DPD (diethyl -p- phenylenediamine) method) value measured by _{(mg / L as Cl 2)} . The concentration of the “stabilized hypobromite composition” can be represented by bromine concentration (mg / L as Br ₂ ), but here, the concentration and the unit of the “chlorine-based oxidizing agent” are compared. Therefore, the “concentration in terms of total chlorine” (mg / L as Cl ₂ ), which is a value measured by the above-described total chlorine measurement method, is used.

The concentration of the “chlorine oxidizing agent” and “stabilized hypobromite composition” is preferably 1 to 10 (mg / L as Cl ₂ ) in terms of total chlorine concentration. When the concentration of the “chlorine-based oxidizing agent” and the “stabilized hypobromite composition” is less than 1 (mg / L as Cl ₂ ), a sufficient bactericidal effect may not be obtained, and 10 (mg) / L as Cl ₂ ), the chemical may remain in public water bodies and adversely affect the environment.

  Examples of the bromine-based oxidizing agent include bromine (liquid bromine), bromine chloride, bromate, bromate, hypobromite and the like.

  Among these, the preparations of "bromine and sulfamic acid compound" or "reaction products of bromine and sulfamic acid compound" using bromine are the preparations of "hypochlorous acid, bromine compound and sulfamic acid" and "bromine chloride". And sulfamic acid ”are more preferable because they have less by-product of bromic acid and a lower possibility of causing corrosion of metal materials such as pipes.

  That is, in the method for disinfecting water according to the present embodiment, it is preferable to add a “chlorine oxidizing agent” and a “reaction product of bromine and a sulfamic acid compound” to water, respectively.

  Examples of the bromine compound include sodium bromide, potassium bromide, lithium bromide, ammonium bromide, and hydrobromic acid. Of these, sodium bromide is preferred from the viewpoint of formulation cost and the like.

  Examples of the chlorine-based oxidizing agent include chlorine gas, chlorine dioxide, hypochlorous acid or a salt thereof, chlorite or a salt thereof, chloric acid or a salt thereof, perchloric acid or a salt thereof, chlorinated isocyanuric acid or a salt thereof. And the like. Among these, examples of the salt include alkali metal hypochlorites such as sodium hypochlorite and potassium hypochlorite, and alkaline earth hypochlorite such as calcium hypochlorite and barium hypochlorite. Metal salts, alkali metal chlorites such as sodium chlorite and potassium chlorite, alkaline earth metal chlorites such as barium chlorite, and other metal chlorites such as nickel chlorite And alkali metal chlorates such as ammonium chlorate, sodium chlorate and potassium chlorate, and alkaline earth metal chlorates such as calcium chlorate and barium chlorate. One of these chlorine-based oxidizing agents may be used alone, or two or more thereof may be used in combination. As the chlorine-based oxidizing agent, sodium hypochlorite is preferably used from the viewpoint of handleability and the like.

The sulfamic acid compound is a compound represented by the following general formula (1).
R ₂ NSO ₃ H (1)
(In the formula, R is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.)

  As the sulfamic acid compound, for example, in addition to sulfamic acid (amidosulfate) in which both R groups are both hydrogen atoms, N-methylsulfamic acid, N-ethylsulfamic acid, N-propylsulfamic acid, N- One of two R groups such as isopropylsulfamic acid and N-butylsulfamic acid is a hydrogen atom, and the other is an alkyl group having 1 to 8 carbon atoms; a sulfamic acid compound; N, N-dimethylsulfamic acid; Two R groups such as N-diethylsulfamic acid, N, N-dipropylsulfamic acid, N, N-dibutylsulfamic acid, N-methyl-N-ethylsulfamic acid and N-methyl-N-propylsulfamic acid; One of two R groups such as a sulfamic acid compound in which both are alkyl groups having 1 to 8 carbon atoms, N-phenylsulfamic acid, etc. An atom, the other is sulfamic acid compound or a salt thereof, such as an aryl group having 6 to 10 carbon atoms. Examples of the sulfamate include, for example, alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt, strontium salt and barium salt, manganese salt, copper salt, zinc salt, iron salt, cobalt salt, and the like. Other metal salts such as nickel salts, ammonium salts, guanidine salts and the like. The sulfamic acid compounds and salts thereof may be used alone or in combination of two or more. As the sulfamic acid compound, it is preferable to use sulfamic acid (amidosulfuric acid) from the viewpoint of environmental load and the like.

  In the method for sterilizing water according to the present embodiment, an alkali may be further present. Examples of the alkali include alkali hydroxides such as sodium hydroxide and potassium hydroxide. Sodium hydroxide and potassium hydroxide may be used in combination from the viewpoint of product stability at low temperatures. The alkali may be used as an aqueous solution instead of a solid.

  In the water disinfection method according to this embodiment, the pH of the water to be treated is preferably in the range of 3 to 11, and more preferably in the range of 4 to 9. If the pH of the water to be treated is less than 3, hypobromite is likely to be volatilized as bromine gas, and the bactericidal effect of the number of coliforms may be reduced. In some cases, the effectiveness of the process according to the present invention is reduced.

  The water to be treated in the water sterilization method according to the present embodiment is, for example, water such as wastewater containing a large amount of ammonia nitrogen or organic substances, and particularly water containing ammonia nitrogen in an amount of 5 mg / L or more, such as sewage. Untreated water discharged from a treatment plant, sewage including rainwater subjected to simple treatment, and the like.

<Stabilized hypobromite composition>
The stabilized hypobromite composition used in the water disinfection method according to the present embodiment includes a `` bromine-based oxidizing agent '' or a `` reactant of a bromine compound and a chlorine-based oxidizing agent '' and a `` sulfamic acid compound '' And may further contain an alkali.

  Further, the stabilized hypobromite composition used in the method for disinfecting water according to the present embodiment is a `` reaction product of a brominated oxidizing agent and a sulfamic acid compound '', or `` a brominated compound and a chlorine oxidizing agent. And a sulfamic acid compound, and may further contain an alkali.

  The bromine-based oxidant, bromine compound, chlorine-based oxidant, and sulfamic acid compound are as described above.

  As the stabilized hypobromite composition used in the water disinfection method according to the present embodiment, bromine and sulfamine are preferred in terms of low corrosiveness to metal materials such as pipes and little by-product of bromate. Those containing an acid compound or those containing a reaction product of bromine and a sulfamic acid compound are preferred.

  The pH of the stabilized hypobromite composition is, for example, more than 13.0, and more preferably more than 13.2. If the pH of the stabilized hypobromite composition is 13.0 or less, the stabilized hypobromite composition may become unstable.

  The bromic acid concentration in the stabilized hypobromite composition is preferably less than 5 mg / kg. When the concentration of bromate in the stabilized hypobromite composition is 5 mg / kg or more, the concentration of bromate ion in the treated water may increase.

<Method for producing stabilized hypobromite composition>
The stabilized hypobromite composition used in the water sterilization method according to the present embodiment is a mixture of a brominated oxidizing agent and a sulfamic acid compound, or a reaction product of a brominated compound and a chlorine oxidizing agent, and sulfamine. It is obtained by mixing with an acid compound, and may further be mixed with an alkali.

  Bromine and a stabilized hypobromite composition containing a sulfamic acid compound, or a method for producing a stabilized hypobromite composition containing a reaction product of bromine and a sulfamic acid compound include water, It is preferable to include a step of adding bromine to a mixed solution containing an alkali and a sulfamic acid compound under an inert gas atmosphere to cause a reaction. By adding and reacting in an inert gas atmosphere, the bromate ion concentration in the composition is reduced.

Used but are not limited to inert gas, at least one and preferably one in terms of nitrogen and argon, such as production, nitrogen is particularly preferred from the viewpoint of production cost and the like.

  The oxygen concentration in the reactor at the time of adding bromine is preferably 6% or less, more preferably 4% or less, further preferably 2% or less, and particularly preferably 1% or less. If the oxygen concentration in the reactor during the reaction of bromine exceeds 6%, the amount of bromic acid generated in the reaction system may increase.

  The addition ratio of bromine is preferably 25% by weight or less, more preferably 1% by weight or more and 20% by weight or less based on the total amount of the composition. If the bromine addition rate exceeds 25% by weight based on the total amount of the composition, the amount of bromic acid generated in the reaction system may increase. If it is less than 1% by weight, the bactericidal effect may be poor.

  The reaction temperature at the time of adding bromine is preferably controlled in the range of 0 ° C. or more and 25 ° C. or less, but is more preferably controlled in the range of 0 ° C. or more and 15 ° C. or less from the viewpoint of production cost and the like. If the reaction temperature at the time of adding bromine exceeds 25 ° C., the amount of bromic acid generated in the reaction system may increase, and if it is lower than 0 ° C., it may freeze.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

In the following Examples and Comparative Examples, the “chlorine-based oxidizing agent” and the “concentration in terms of total chlorine” of the “stabilized hypobromite composition” refer to the HACH company's multi-item water quality analysis by appropriately diluting the sample. with a total of DR / 4000, the total chlorine assay of HACH PROGRAM 1450 (DPD (diethyl -p- phenylenediamine) method) value measured by _{(mg / L as Cl 2)} . The concentration of the “stabilized hypobromite composition” can be represented by bromine concentration (mg / L as Br ₂ ), but here, the concentration and the unit of the “chlorine-based oxidizing agent” are compared. Therefore, the “concentration in terms of total chlorine” (mg / L as Cl ₂ ), which is a value measured by the above-described total chlorine measurement method, was used.

<Preparation of stabilized hypobromite composition>
The stabilized hypobromite compositions A, B, and C used in the examples are as follows.

[Preparation of stabilized hypobromite composition A]
Under a nitrogen atmosphere, liquid bromine: 16.9% by weight (wt%), sulfamic acid: 10.7% by weight, sodium hydroxide: 12.9% by weight, potassium hydroxide: 3.94% by weight, water: residual The composition was prepared by mixing the minutes. The composition had a pH of 14 and a bromine content (concentration) of 16.9% by weight (as Br ₂ ). The concentration of bromine in terms of total chlorine was 7.5% by weight (as Cl ₂ ). The detailed preparation method of the stabilized hypobromite composition A is as follows.

  1436 g of water and 361 g of sodium hydroxide were added to a 2 L four-necked flask sealed by continuous injection while controlling the flow rate of nitrogen gas with a mass flow controller so that the oxygen concentration in the reaction vessel was maintained at 1%. After mixing and then adding 300 g of sulfamic acid and mixing, 473 g of liquid bromine was added while maintaining the temperature of the reaction solution at 0 to 15 ° C., and 230 g of a 48% potassium hydroxide solution was further added. The intended stabilized hypobromite composition A, wherein the weight ratio of sulfamic acid to the total amount of the composition is 10.7%, the bromine content is 16.9%, and the equivalent ratio of sulfamic acid to the equivalent of bromine is 1.04. I got The pH of the resulting solution was 14, as measured by the glass electrode method. The bromine content of the resulting solution was measured by a method of converting bromine into iodine with potassium iodide and then performing redox titration with sodium thiosulfate, and found to be 16.9%. The theoretical bromine content (16.9) %). The oxygen concentration in the reaction vessel during the bromine reaction was measured using "Oxygen Monitor JKO-02 LJDII" manufactured by Jiko Co., Ltd. The bromate concentration was less than 5 mg / kg.

The pH was measured under the following conditions.
Electrode type: Glass electrode type pH meter: Toa DKK, IOL-30 type Calibration of electrode: Neutral phosphate pH (6.86) standard solution (2nd class), Kanto Chemical Co., boric acid Performed by two-point calibration of salt pH (9.18) standard solution (second type) Measurement temperature: 25 ° C
Measured value: The electrode was immersed in the test solution, and the value after stabilization was taken as the measured value, the average of three measurements

[Preparation of stabilized hypobromite composition B]
Sodium bromide: 11% by weight, 12% aqueous solution of sodium hypochlorite: 50% by weight, sodium sulfamate: 14% by weight, sodium hydroxide: 8% by weight, water: The residue is mixed to prepare a composition. did. The composition had a pH of 14 and a bromine content (concentration) of 13.5% by weight (as Br ₂ ). The concentration of bromine in terms of total chlorine was 6% by weight (as Cl ₂ ). The detailed preparation method of the stabilized hypobromite composition B is as follows.

  17 g of water was put in a reaction vessel, 11 g of sodium bromide was added and stirred to dissolve, 50 g of a 12% aqueous sodium hypochlorite solution was added and mixed, and then 14 g of sodium sulfamate was added and stirred. After dissolution, 8 g of sodium hydroxide was added, and the mixture was stirred and dissolved to obtain the intended stabilized hypobromite composition B.

[Preparation of stabilized hypobromite composition C]
A stabilized hypobromite composition C was prepared based on the description in International Patent Application Publication No. 03/093171. The stabilized hypobromite composition C is a composition containing liquid bromine, sulfamate, and sodium hydroxide. The stabilized hypobromite composition C had a pH of 14 and a bromine content (concentration) of 16.1% by weight (as Br ₂ ). The concentration of bromine in terms of total chlorine was 7.1% by weight (as Cl ₂ ). The equivalent ratio of sulfamic acid to bromine equivalent was 1.45.

<Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-4>
A germicidal test was performed using the sewage having the water quality described in Table 1. 300 mL of sewage is placed in a 300 mL beaker, and a chemical (stabilized hypobromite composition A and sodium hypochlorite) is added thereto so that the total concentration in terms of total chlorine becomes 5 mg / L as Cl ₂ as shown in Table 2. ) Was added and the mixture was stirred with a digital stirrer at 250 rpm. At this time, as a method of adding the chemical, a method of simultaneously adding the stabilized hypobromite composition A and sodium hypochlorite directly to the water to be treated (Examples 1-1 to 1-6); The bromite composition A and sodium hypochlorite were previously mixed and added by two methods (Comparative Examples 1-4). In addition, no drug was added (Comparative Example 1-1), a single agent was added with sodium hypochlorite (Comparative Example 1-2), and a single agent was added with stabilized hypobromite composition A (Comparative Example 1-3). Was also tested. Five minutes after all the chemicals were added, a predetermined amount of treated water was collected, and sodium thiosulfate was added to inactivate available chlorine. Then, the number of coliform bacteria in Petrifilm (trademark) medium manufactured by 3M Corporation was measured. The number of coliforms was measured by using a CC plate. Table 2 shows the results.

  By adding the stabilized hypobromite composition A and sodium hypochlorite together and directly to the sewage (Examples 1-1 to 1-6), the stabilized hypobromite composition A or When sodium chlorite is added as a single agent (Comparative Example 1-3, Comparative Example 1-2), the stabilized hypobromite composition A and sodium hypochlorite are mixed in advance and then added. It showed higher sterilization performance than the case (Comparative Example 1-4).

<Examples 1-7 and 1-8>
In the same test method as in Example 1-5, the agent as a stabilizing hypobromite composition A and (1.0mg / L as Cl ₂₎ and sodium hypochlorite (4.0mg / L as Cl ₂₎ A method of adding sodium hypochlorite and adding the stabilized hypobromite composition A 15 seconds later (Example 1-7), adding the stabilized hypobromite composition A 15 seconds later, sodium hypochlorite was added (Example 1-8). It compared with the method (Example 1-5) of simultaneously adding the said chemical | medical agent to to-be-processed water. The time was defined as 0 minutes from the time when the drug was added first, and the number of coliform bacteria was measured 5 minutes after that. Table 3 shows the results.

  When sodium hypochlorite was added after adding the stabilized hypobromite composition A (Example 1-8), the stabilized hypobromite composition A and sodium hypochlorite were simultaneously added directly. In the case (Example 1-5), the effect of reducing the number of coliform bacteria was higher than that in the case where the stabilized hypobromite composition A was added after the addition of sodium hypochlorite (Example 1-7). Was.

<Example 2 and Comparative Examples 2-1 and 2-2>
In the same test method as in Examples 1-1 to 1-8, stabilized hypobromite composition B was used instead of stabilized hypobromite composition A as a drug. At this time, as a method of adding the chemical, stabilized hypobromite composition B (1.0 mg / L as Cl ₂ ) and sodium hypochlorite (4.0 mg / L as Cl ₂ ) are simultaneously added to the water to be treated. Two methods, a direct addition method (Example 2) and a method in which stabilized hypobromite composition B and sodium hypochlorite are mixed in advance and then added (Comparative Example 2-1) did. In addition, a test was also performed on the addition of a single agent of the stabilized hypobromite composition B (Comparative Example 2-2), and no agent was added (Comparative Example 1-1), and a single agent of sodium hypochlorite was added (Comparative Example 1-1). This was compared with Comparative Example 1-2). Table 4 shows the results.

  The stabilized hypobromite composition B or sodium hypochlorite was used in combination with sodium hypochlorite and directly added to the sewage (Example 2) to thereby stabilize the stabilized hypobromite composition B or sodium hypochlorite. (Comparative Example 2-2, Comparative Example 1-2), when the stabilized hypobromite composition B and sodium hypochlorite are mixed in advance and then added (Comparative Example 2- It showed higher sterilization performance than 1).

<Example 3 and Comparative Examples 3-1 and 3-2>
In the same test method as in Examples 1-1 to 1-8, stabilized hypobromite composition C was used instead of stabilized hypobromite composition A as a drug. At this time, as a method of adding the chemical, stabilized hypobromite composition C (1.0 mg / L as Cl ₂ ) and sodium hypochlorite (4.0 mg / L as Cl ₂ ) were simultaneously added to the water to be treated. Two methods, a direct addition method (Example 3) and a method in which stabilized hypobromite composition C and sodium hypochlorite are mixed in advance and then added (Comparative Example 3-1) did. In addition, a test was also performed on the addition of a single agent of the stabilized hypobromite composition C (Comparative Example 3-2), and no agent was added (Comparative Example 1-1), and a single agent of sodium hypochlorite was added (Comparative Example 1-1) This was compared with Comparative Example 1-2). Table 5 shows the results.

  The stabilized hypobromite composition C and sodium hypochlorite were used in combination and directly added to the sewage (Example 3), whereby the stabilized hypobromite composition C or sodium hypochlorite was simply added. (Comparative Example 3-2, Comparative Example 1-2), when the stabilized hypobromite composition C and sodium hypochlorite are mixed in advance and then added (Comparative Example 3- It showed higher sterilization performance than 1).

  Thus, by adding the chlorine-based oxidizing agent and the stabilized hypobromite composition A, the stabilized hypobromite composition B, or the stabilized hypobromite composition C to the wastewater, respectively, After 5 minutes, the number of coliforms became 3000 / mL or less, and the effect of reducing the number of coliforms was obtained in a short time.

Claims (5)

A method for disinfecting water, comprising adding a chlorine-based oxidizing agent and a stabilized hypobromite composition to water containing at least 20 mg / L of ammoniacal nitrogen,
The stabilized hypobromite composition,
A bromine-based oxidant or a reaction product of a bromine compound and a chlorine-based oxidant;
A sulfamic acid compound;
Including
The chlorine-based oxidizing agent, Ri hypochlorous acid or a salt thereof der,
The ratio (b / a) of the total chlorine equivalent addition concentration (b) of the stabilized hypobromous acid composition to the total chlorine equivalent addition concentration (a) of the chlorine-based oxidizing agent is 0.11 to 9%. sterilization method of water which is characterized the range der Rukoto of 00. A method for disinfecting water, comprising adding a chlorine-based oxidizing agent and a stabilized hypobromite composition to water containing at least 20 mg / L of ammoniacal nitrogen,
The stabilized hypobromite composition,
A bromine-based oxidant or a reaction product of a bromine compound and a chlorine-based oxidant;
A sulfamic acid compound;
Containing the reaction product of
The chlorine-based oxidizing agent, Ri hypochlorous acid or a salt thereof der,
The ratio (b / a) of the total chlorine equivalent addition concentration (b) of the stabilized hypobromous acid composition to the total chlorine equivalent addition concentration (a) of the chlorine-based oxidizing agent is 0.11 to 9%. sterilization method of water which is characterized the range der Rukoto of 00. A method for disinfecting water, comprising adding a chlorine-based oxidizing agent and a stabilized hypobromite composition to water containing at least 20 mg / L of ammoniacal nitrogen,
The stabilized hypobromite composition comprises a reaction product of bromine and a sulfamic acid compound,
The chlorine-based oxidizing agent, Ri hypochlorous acid or a salt thereof der,
The ratio (b / a) of the total chlorine equivalent addition concentration (b) of the stabilized hypobromous acid composition to the total chlorine equivalent addition concentration (a) of the chlorine-based oxidizing agent is 0.11 to 9%. sterilization method of water which is characterized the range der Rukoto of 00. A method for sterilizing water according to any one of claims 1 to 3,
The ratio (b / a) of the total chlorine equivalent addition concentration (b) of the stabilized hypobromous acid composition to the total chlorine equivalent addition concentration (a) of the chlorine-based oxidizing agent is 0.11 to 0.1. 67. A method for disinfecting water, wherein the range is 67. A method for sterilizing water according to any one of claims 1 to 4 ,
A method for disinfecting water, comprising adding the stabilized hypobromite composition to the water and then adding the chlorine-based oxidizing agent.