JP2554989B2 - Sterilization method in water system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilization method in a water system, and more particularly to a method capable of preventing slime troubles in a cooling water system, a papermaking process and the like.

[0002]

2. Description of the Related Art The main uses of industrial water are cooling water,
There are treatment water for products, washing water, water for temperature control, etc., and in these applications, failures caused by microorganisms frequently occur. In particular, viscous substances secreted by microorganisms are mixed with sediment in water, iron rust, other organic substances, etc. to produce a mud called slime,
This will cause many obstacles in the operation of the factory. In cooling water systems, the recovery and reuse of water has become popular in order to make up for the shortage of water and reduce the cost of water. In this case, the cooling water is mainly used after being recooled in the cooling water tower, so that the water is concentrated, and at the same time, the concentration of nutrients and pollutants is increased, and the propagation of microorganisms becomes more active. When the growth of bacteria, algae and fungi is promoted, and the adsorption of pollutants is also added thereto, slime formation is further increased. Adhesion and breeding of slime not only hinders the passage of water through the strainer and heat transfer of the heat exchanger, but also reduces the flow rate of cooling water due to the reduction of the cross-sectional area of the pipe, and in the more significant case, clogging of the pipe. Promotes pitting corrosion. As a measure against slime, generally, various fungicides, growth inhibitors and algaecides are used to suppress or kill the growth of microorganisms. It is often used because it is effective.

A large amount of industrial water is used in paper mills, but it becomes increasingly difficult to secure good quality industrial water, and due to environmental problems, a large amount of waste water cannot be discharged. For this reason, process water is being reused, but when water is reused in this way, suspended solids such as dissolved substances, pulp, starch, and talc are concentrated in the circulating water, promoting the growth of microorganisms. At the same time, slime is very likely to be generated due to the accumulation of suspended matter. Slime is generated not only in the water system but also in the white water pit, flow box, piping, etc. in the papermaking process. When the slime formed in the papermaking process grows to a certain extent, it is peeled off from the wall surface and mixed with pulp to make paper. For this reason, the paper contains slime, and the paper strength of the slime portion remarkably decreases, which easily causes paper breakage in the drying process. Further, when a paper containing slime is used as a product, coloring, spots, and eyeballs are generated on the surface of the paper, and this phenomenon is particularly noticeable in high-quality paper, so that the product value is remarkably reduced. As described above, when slime is generated in the paper manufacturing process, a great economic loss is brought about. Since the effect of the chlorine-based bactericide is lowered in a system containing a large amount of organic components such as in the paper manufacturing process, the organic halogen-based bactericide is mainly used for slime control, but the effect is still not sufficient.

[0004]

If the amount of the bactericide is increased excessively, not only the cost will increase but also the device will be adversely affected, which is not preferable.

An object of the present invention is to provide a sterilizing method in an industrial water system in which the sterilizing power is dramatically improved while suppressing the increase in the amount of the sterilizing agent.

[0006]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to establish a large sterilization method with high penetrability and a small amount of bactericide in order to prevent slime in industrial water systems. It has been found that a strong bactericidal power can be exhibited with a small amount of bactericide by simultaneously acting a specific organic bromine compound and a chlorine agent, and the present invention has been completed.

That is, according to the present invention, α-
Aliphatic bromine compound having at least one selected from a cyano group, a nitro group, a carbonyl group, a carboxyl group, an amide group, an alkoxyl group, a hydroxyl group and a sulfone group as a substituent on the carbon atom at the position and / or β-position , And one or two or more kinds of organic bromine compounds selected from the group consisting of N-bromimide compounds as a solution, which is premixed with a chlorine agent, and then added to the water system. It is about the method.

The organic bromine compound of the present invention is an aliphatic bromine compound or an N-bromimide compound, and has cyano group, nitro group, carbonyl group, carboxyl group,
The bromine-carbon bond or the bromine-nitrogen bond is weakened by an amide group, an alkoxyl group, a hydroxyl group, a sulfone group and the like. In the aliphatic bromine compound, the number of these substituents bonded to the α-position and / or the β-position is usually about 1 to 3. The molecular weight of the organic bromine compound is not particularly limited, but it is in a form capable of reacting with a chlorine agent in an aqueous system, that is, dissolved in water or in a liquid state at the water temperature. The bactericidal action can be exerted on microorganisms that easily propagate in industrial water systems. The bactericidal action does not have to be exerted on all microorganisms, and for that purpose or for other purposes two or more organic bromine compounds can be combined. Examples of such organic bromine compounds include 2-bromo-2-nitro-
1,3-propanediol, 2-bromo-2-nitro-
1,3-Pentanediol, 2,2-dibromo-2-nitroethanol, 2,2-dibromo-3-nitrilopropionamide, 1,1-dibromo-2-nitro-2-acetoxyethane, 2-bromo-2 -Nitro-1,3-diacetoxypropane, 1,2,3-tris (bromoacetoxy) propane, benzyl bromoacetate, 1,3
-Diacetoxy-2-bromo-2-nitropropane,
1,1-dibromo-1-nitropropanol-2,2-
Nitro-3-bromo-n-butyl monobromoacetate, bis (tribromomethyl) sulfone, bromodicyanoacetamide, 2-butoxyethyl bromoacetate, (2-butoxy-1-methyl) -ethyl bromoacetate, bromoacetic acid, 2 -Bromobutyric acid, 2-bromopropionic acid, 1,4-dibromo-2,3-butanedione,
Examples include bromopyruvic acid ethyl ester, 2-bromoethanol, dibromopropanol, N-bromosuccinimide and the like.

The chlorine agent generates effective chlorine having an oxidizing action in water, and is chlorine gas, hypochlorite, chlorine dioxide or the like. Examples of hypochlorites include sodium hypochlorite and calcium hypochlorite.

The mixing ratio of the organic bromine compound and the chlorine agent is arbitrarily selected, but in order to exert a remarkable effect in the method of the present invention, a sufficient amount of the chlorine agent for activating the bromine atom in the organic bromine compound is used. is necessary. That is, the addition amount of the chlorine agent is an amount sufficient to activate the bromine atom in the organic bromine compound, and one chlorine atom corresponds to one bromine atom. Practically, the ratio of the number of bromine atoms in the organic bromine compound to the number of available chlorine generated by the chlorine agent is 1: 1 to 1:10.
It is 0, preferably 1: 1 to 1: 5. Although there is some effect outside this range, the effect does not increase relative to the amount added, which is economically undesirable.

The amount added to the water system varies depending on the number of bacteria in the water, the water quality, the temperature, and other operating conditions, but generally the active bromine compound is 0.01 to 1000 ppm, preferably 0.1 to It is 100 ppm. Here, the active bromine compound is generated from the organic bromine compound by the action of the chlorine agent. The effect is small at 0.01 ppm or less, 1000 ppm
Although the above-mentioned effects are obtained, the effects are not increased relative to the amount added, which is economically unfavorable.

In the sterilization method of the present invention, an organic bromine compound is made into a solution having an appropriate concentration, a chlorine agent is added thereto, and the mixture is mixed in advance and then added to an aqueous system. When mixing the organic bromine compound and the chlorine agent, the chlorine agent may be simply added to the solution of the organic bromine compound, but it may be preferable to acidify the solution of the organic bromine compound and add the chlorine agent to the solution.
However, the present invention does not specifically limit such a mixing method.

In the method of the present invention, at the same time,
There is no limitation on the addition of other germicidal agents, germicides, slime dispersants, anticorrosives, and scale inhibitors. Further, there is no limitation on the combined use with an inorganic bromine compound such as sodium bromide (NaBr).

[0014]

[Function] The conventional disinfectant treatment is for the purpose of only killing the microorganisms. The microorganisms are dispersed in sterilized water and the sterilizing agent is added thereto to kill the microorganisms by changing the turbidity or the colony counting method. It has been developed using the degree as an index. However, in an actual system, viscous substances secreted by microorganisms, mud and sand in water, iron rust, pulp, and other organic substances are mixed to form slimes, and the microorganisms inhabit. Therefore, even if it has the ability to kill microorganisms floating in water, it is insufficient as a bactericidal agent unless it acts on such microorganisms covered with organic matter. In fact, it has been reported that attached microorganisms are more resistant to chemicals than suspended microorganisms [Microbial Ecology 16 (Academic Publication Center) p. 37], using glucanase to control slime. A method for compensating the bactericidal activity by decomposing polysaccharides secreted by microorganisms (JP-A-3-193),
It has been reported that it is necessary to reduce the viscosity of polysaccharides secreted by microorganisms in order to remove slime (Japanese Patent Laid-Open No. 5-1557).
No. 19) is also available. It is suggested that it is necessary to consider not only the microorganisms but the entire slime including the surrounding organic matter. In addition, many types of microorganisms are covered with extracellular polysaccharides and capsular (capsule) polysaccharides that are secreted by themselves, and the bactericide often does not reach the bacterial cells. However, it is easier to produce slime as the microorganisms secreting such polysaccharides. However, it is meaningless as a bactericidal treatment agent unless it has an effect on microorganisms having a high ability to form slime. Since conventional bactericides have not been developed from the viewpoint of such sterilizing agents, even if it is confirmed that the number of bacteria in the water is reduced by adding the bactericide to the cooling water system or the paper manufacturing process, slime The inventor of the present invention considered that there was a lot of contradiction that the above-mentioned phenomenon occurred, and reached the present invention.

Regarding the bactericidal action of bromine compounds, it has been conventionally known that hypobromic acid is produced from sodium bromide and sodium hypochlorite, which has a higher pH than sodium hypochlorite alone. Has excellent bactericidal effect (JE Alleman etc, Water Reuse Symposium 5 o
f American Water Works Association Aug / 1987, JE
Alleman etc, 42 nd Annual Purodue Industrial Wate
r Conference May / 1987), brominated acetic acid is effective in controlling mussels (Japanese Patent Publication No. 52-84), alkyl brominated acetic ester is effective in suppressing the growth of algae (Japanese Patent Publication 6).
No. 0-46082) and the bactericidal power of nitroalkyl bromide alone (JP-A-59-175406). However, these methods are still insufficient when it comes to killing microorganisms covered with slime and polysaccharides.

The present invention is a method for preventing slime in an industrial water system, let alone microorganisms floating in water.
It provides a method for preventing slime by killing microorganisms inhabiting slime, and penetrating extracellular polysaccharide or capsular polysaccharide to directly act on microorganisms covered with these polysaccharides to kill them. is there.

The organic bromine compound and the chlorine agent used in the method of the present invention have a proper bactericidal action by themselves. However, when these organic bromine compounds and chlorine agents are combined, a more remarkable bactericidal action with penetrating power is exhibited. The organic bromine compound of the present invention has a weak bromine-carbon bond or bromine-nitrogen bond in the molecule, and the chlorine agent acts on the bromine-carbon bond or the bromine-nitrogen bond in the molecule, and the organic bromine compound in the active state. make. This active organobromine compound has the property of penetrating into the inside of slime substances and slime substances such as extracellular polysaccharides and capsular polysaccharides secreted by microorganisms, and it is possible to sterilize the microorganisms living in these. became.

[0018]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

[Organic Bromine Compound Used in Examples] Compound-A: 2-Bromo-2-nitro-1,3-propanediol (“Mayaside AS” manufactured by Booth Co.) Compound-B: 2,2-dibromo- 2-Nitroethanol (“DBNE” manufactured by Nagase Kasei Co., Ltd.) Compound-C: 2,2-dibromo-3-nitrilopropionamide (“DBNPA” manufactured by Rohm and Haas Co.) Compound-D: 1,2,3- Tris (bromoacetoxy) propane (“TBAP” manufactured by Ichikawa Gosei Co., Ltd.) Compound-E: benzyl bromacetate (CALGON
"Melvac-35" manufactured by the company) Compound-F: 1,2-bis (bromoacetoxy) propane ("BBAP" manufactured by Ichikawa Gosei Co., Ltd.) Compound-G: 1,3-diacetoxy-2-bromo-2-
Nitropropane ("HF-DABN" manufactured by Nagase Kasei Co., Ltd.)
P ") Compound-H: Bromoacetic acid (Kanto Chemical Co., Inc. reagent) Compound-I: 2-Bromopropionic acid (Kanto Chemical Co., Ltd. reagent) Compound-J: 2-Bromobutyric acid (Kanto Chemical Co., Ltd.) Reagent) Compound-K: Brompyruvic acid ethyl ester (Aldrich reagent) Compound-L: 2-Bromoethanol (Kanto Chemical Co., Inc.)
Reagent) Compound-M: Dibromopropanol (manac company) Compound-N: Bromosuccinimide (manufactured by Kanto Chemical Co., Inc.)
Reagent) The above organic bromine compound is acetone-water (1: 1 volume ratio)
Dissolved in the mixture.

[Bactericidal agent used in the examples] 0.2 ml of an aqueous solution of sodium hypochlorite (effective chlorine concentration: 5%) was added to 1 ml of a 1% by weight solution of an organic bromine compound to prepare a test sample. For comparison, 1 ml of pure water plus 0.2 ml of sodium hypochlorite aqueous solution, 1% by weight of each organic bromine compound
A solution was prepared by adding 0.2 ml of pure water to 1 ml of the solution.

[Strain used in Examples] Escherechia coli (IAM-12119) Staphrococcus aureu
s: IAM-12544) Pseudomonas aeruginos
a: IFO-12689) Pseudomonas fluorec
ens: IAM-1154) Bacillus coaqulans: IFO
−12583) Beijerinckia indica:
IFO-3745) Alcaligenes latus B-16
-16: FERM BP-2015) Xanthmonas campestr
is: IFO-13551) Trichoderma viride: IFO-5
720) Saccharomyces cerevisia
e: IAM-4274)

[Example 1] Escherichia coli cells adjusted to the logarithmic growth phase, Staflococcus aureus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Bacillus coagulum were each added to 1 platinum loop, 10 ml.
After adding 0.1 ml to the plate of nutrient broth (pH = 6.8) (manufactured by Dicffico), the suspension was added to the sterilized water of the above to make a suspension, and the mixture was evenly spread with a conradi stick. A sterilized glass filter having a diameter of 5 mm was placed on the center portion, and 0.02 ml of the sterilization treatment agent sample was dropped.

After culturing at 30 ° C. for 3 days, the growth inhibition area of the fungus was measured. Since there is no growth of the bacterium in the area where the bactericidal agent has penetrated, the wider the growth inhibition area of this bacterium, the higher the bactericidal ability of the bactericidal agent in the agar medium (in organic matter) and the higher the bactericidal ability. Shows. The results are shown in Table 1.

[0024]

[Table 1]

From these results, the combination of the organic bromine compound and sodium hypochlorite has a markedly improved osmotic power and is capable of sterilizing a wide range as compared with the organic bromine compound alone and the sodium hypochlorite alone. It was recognized that it was possible.

[Example 2] Escherichia coli cells, Staflococcus aureus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Bacillus coagulans adjusted to the logarithmic growth phase, 1 platinum loop, 10 ml, respectively
Sterilized water to make a suspension, and add these bacterial solutions to glycine Na
0.1 ml was added dropwise to a nutrient broth plate adjusted to pH = 8.5 by adding a buffer solution, and glycine Na buffer solution was further added to adjust the pH value to 8.5, and then uniformly spread with a conradi stick. In the same manner as in Example 1,
A sterilized glass filter was placed on the center, 0.02 ml of the sterilizing agent solution was dropped on the glass filter, and the mixture was incubated at 30 ° C. for 3 days, and then the growth inhibition area of the bacterium was measured. Table 2 shows the results.

[0027]

[Table 2]

From these results, it was confirmed that even at pH = 8.5, the combination of the organic bromine compound and sodium hypochlorite has excellent penetrating power and can sterilize a wide range.

Example 3 To 1 ml of a 1% by weight solution of an organic bromine compound, 0.1 ml of 3% hydrochloric acid was added to adjust the pH to 3 or less, and sodium hypochlorite (reagent having an effective chlorine concentration of 5%) was added thereto.
0.2 ml was added to make a sterilization treatment agent sample. For comparison, 1 ml of pure water plus 0.2 ml of sodium hypochlorite,
A solution was prepared by adding 0.2 ml of pure water to a 1% by weight solution of the organic bromine compounds A to S. Escherichia coli cells adjusted to the logarithmic growth phase were suspended in 10 ml of sterile water with 1 platinum loop. Nutrient
Broth pH = 6.8 plate and 0.1 ml of each were added to a plate of nutrient broth prepared by adding glycine Na buffer to pH = 8.5, and then uniformly spread well with a conradi stick. 0.02 ml of the sterilizing agent solution was dropped on a sterile glass filter placed at the center of the filter, and the mixture was cultured at 30 ° C. for 3 days. For each sterilizing agent,
The growth inhibition area of the bacterium was measured. The results are shown in Table 3.

[0030]

[Table 3]

From these results, the mixture of the organic bromine compound and sodium hypochlorite at a low pH has a larger penetration power and a bactericidal power than the organic bromine compound alone or the sodium hypochlorite alone. It turns out to be big.

[Example 4] PDA plate (Tanabe Seiyaku)
Ltd.) Cultured Tricohdermaviri
de: fungi) was placed in sterilized water to prepare a spore suspension containing 1 × 10 ⁸ cells / ml. Further, after adjusting Saccharomyces cerevisiae (yeast) to the logarithmic growth phase, 1 platinum loop was put into 10 ml of sterilized water and well shaken to prepare a suspension. These bacterial solutions were dropped on a PDA plate and then uniformly spread with a conradi stick. 0.02 ml of the sterilizing agent solution was dropped on a sterilized glass filter placed at the center of the filter, and the mixture was cultured at 25 ° C for 5 days. The growth inhibition area of the bacterium was measured for each sterilizing agent. The results are shown in Table 4.

[0033]

[Table 4]

From these results, it can be seen that the mixture of the organic bromine compound and sodium hypochlorite has a large osmotic power and a large bactericidal power against molds and yeasts.

[Example 5] Each of strains Beijerinckia indica (Beijerinckia indica) whose cells are covered with polysaccharides, Alcaligenes latus B-16, and Xanthmonas campestris are used. A sterilization test in water was performed. Escherechia coli was used as a control. These strains in the logarithmic growth phase were placed in 100 ml of sterile water to prepare a suspension. After measuring the number of bacteria in this bacterial solution by the colony counting method, add 0.05 ml of the bactericidal treatment solution and add it to 30 ° C.
After shaking for 1 hour, the number of bacteria was measured again by the colony counting method. The survival rate (%) was obtained from the measured values of the number of bacteria before and after the addition of the disinfectant treatment agent, and the disinfectant treatment agent was evaluated.
The results are shown in Table 5.

[0036]

[Table 5]

From these results, sodium hypochlorite alone sterilized Escelesia coli, which was used as a control, but the strains Beigelinchia indica, Alcaligenes reitus B-16, and Xanthomonas campestris, which were covered with polysaccharides, were killed. Has no bactericidal effect. This is because the bacteria are protected by polysaccharides. The organic bromine compound alone has no bactericidal effect against any bacteria. However, when the organic bromine compound of the present invention and sodium hypochlorite are combined, a very strong bactericidal effect is exerted not only on Escherichia coli, but also on the strains Beigericia indica, Alcaligenes lettus B-16, and Xanthomonas campestris which are covered with polysaccharides. showed that.

[0038]

According to the method of the present invention, it is possible to exert a strong bactericidal force with a large penetrating force in an aqueous system with a small amount of the bactericide. As a result, the microorganisms in the water are killed, and the viscous substances secreted by the microorganisms, the sediment in the water, iron rust, pulp, and other organic substances permeate the entangled slime to kill the microorganisms inhabiting. In addition, it can permeate extracellular polysaccharides and capsular polysaccharides and directly act on the microorganisms covered with these polysaccharides to kill them. Further, since it has strong permeability, slime already formed can lose its cohesiveness, and the slime can be dispersed and eliminated. Further, the method of the present invention has a large sterilizing power even at a high pH and is less corrosive as compared with the conventional chlorine-based bactericides, and is therefore preferable for industrial use.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display area A01N 29/02 A01N 29/02 C02F 1/76 C02F 1/76 A (56) References 50-79163 (JP, A) JP 60-129182 (JP, A) JP 4-35788 (JP, A) JP 58-96003 (JP, A) JP 1-254287 (JP, A) Japanese Patent Publication Sho 46-6640 (JP, B1)

Claims (2)

(57) [Claims] 1. An α-position and / or β with respect to a bromine atom
Aliphatic bromine compound having, as a substituent, at least one selected from a cyano group, a nitro group, a carbonyl group, a carboxyl group, an amide group, an alkoxy group, a hydroxyl group and a sulfone group at the 1-position carbon atom, and N-bromimide A method for sterilizing treatment in an aqueous system, characterized in that a solution of one or more organic bromine compounds selected from the group consisting of compounds is mixed with a chlorine agent in advance and then added to the aqueous system. 2. The chlorine agent is chlorine, sodium hypochlorite,
The sterilization method according to claim 1, which is one kind or two or more kinds selected from calcium hypochlorite and chlorine dioxide.