CZ135497A3 - Synergetic biocidal mixture - Google Patents

Abstract

The present invention is directed to microbiocidal combinations and processes for inhibiting the growth of microorganisms. The novel combinations and processes of the present invention show unexpected activity against microorganisms, including bacteria, fungi and algae. Specifically, the microbiocidal combinations comprise (i) an oxidant or oxidizing biocide such as potassium monopersulfate, sodium perborate, hydrogen peroxide or sodium percarbonate, (ii) a non-oxidizing microbiocide such as glutaraldehyde and optionally (iii) a surfactant/dispersant, (iv) an anti-corrosive material, and (v) an anti-scale material.

Description

BACKGROUND OF THE INVENTION

The invention relates to synergistic microbiocidal agents and methods utilizing these synergistic microbiocidal agents to inhibit the growth of microorganisms in aqueous systems. In particular, the synergistic microbiocidal compositions of the invention comprise a combination of (i) an oxidant and (ii) a non-oxidizing microbiocide, optionally with a surfactant / dispersing and anticorrosive material and / or anti-scaling material.

BACKGROUND OF THE INVENTION

The growth of microorganisms and the resulting slime formation is a problem commonly found in many aqueous systems. Problematic mucus producing microorganisms include bacteria, airborne microorganisms, sulfate-reducing bacteria, fungi and algae. Slime deposits are commonly found in many aqueous industrial systems, including water cooling, for example in paper and pulp mills, oil processing, industrial lubricants, coolants and coolants. The formation of slime by the action of microorganisms in these systems is a significant and persistent problem.

Slime deposits damage, for example, wooden cooling towers and promote corrosion when deposited on the metal surface of water cooling systems. In addition, slime deposits tend to clog and clog pipes and valves and reduce heat exchange or cooling efficiency of heat transfer surfaces.

Systems in pulp and paper mills operate under conditions that promote the growth of microorganisms and often lead to clogging problems. In addition, microorganisms can form large slime deposits that can be released and will appear as holes, holes or cracks in the paper produced. This requires interrupting the operation of the papermaking process to clean the equipment and leads to time loss.

Slime can also be a nuisance in terms of cleanliness and remediation in breweries, wine makers, dairies and other industrial food and beverage processes operating with water systems. In addition, sulphate-reducing bacteria are a common problem in waters used for secondary oil extraction or in oil wells in general. For example, these organisms reduce the sulphates present in the injection water to form deposits of insoluble iron sulphide and can promote metal corrosion by accelerating the galvanic action.

The growth of bacteriological contamination in lubricants and cutting fluids is a known problem due to elevated temperatures and non-remediation conditions in many metalworking plants. Sometimes it is necessary to discard these liquids for microbiological contamination.

Because of these problems in many industrial processes, many biocidal materials are used to eliminate or reduce microbial growth. Various oxidizing biocides, including chlorine, chlorine dioxide and bromine, have found widespread use in such applications. However, these oxidizing biocides are not always effective to control microbiological growth. For example, oxidizing biocides are consumed by inorganic substances such as divalent iron, reduced manganese and sulfides, as well as organic compounds that are commonly found in these systems.

In addition, the effectiveness of the biocide is rapidly lost due to exposure to harmful physical conditions such as temperature or contact with incompatible water treatment agents in the system.

Therefore, it has hitherto been necessary to use multiple doses of large quantities of expensive biocidal chemicals to keep microbial growth under control.

SUMMARY OF THE INVENTION It is an object of the present invention to provide novel microbiocidal compositions with improved efficiency in controlling and inhibiting the growth of microorganisms in aqueous systems.

It is a further object of the invention to provide an improved method for controlling microorganisms in aqueous systems such as papermaking and cellulose-producing systems, water cooling systems, liquids in the metalworking industry, and in petroleum processing.

Yet another object of the invention is to reduce the level of toxic biocides in industrial waste water. It is an advantage of the invention that the synergistic biocidal compositions make it possible to reduce the dosage of biocides required for the treatment of microbiological pollution in industrial waters and to significantly reduce the time required to combat microbiological organisms.

SUMMARY OF THE INVENTION

The synergistic biocidal composition according to the invention consists of:

(i) microbiocidally to inhibit growth comprising a monomer amount of a microorganism oxidizing agent selected from diperoxyorganic acid, halogen dioxides, monopersulfates, halogens, halogen releasing compounds, perborates, peroxides, percarbonates, persulfates, permanganates, ozone and mixtures thereof; and (ii) microbiocide an effective amount of a microbiocide to inhibit the growth of microorganisms selected from glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decylthio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitroethyl) furan, poly (oxyethylene (dimethylimino)) ethylene (dimethylimino) ethylene dichloride), and 1-alkyldimethylbenzylammonium chloride, alkylamidopropylpropylene glycol, dimethalammonium chloride phosphate, 2,4,4'-trichloro-2'-hydroxydiphenyl ether, tetrakis-hydroxylmethylphosphonium sulfate, tributyltetradecylchloride

2-nitropropane-1,3-diol, 2,2-dibromo-2-nitroethanol, and sanquinaria extract.

A method for controlling or inhibiting microbial growth in aqueous systems is to add to the system (i) microbiocidally to inhibit growth comprising monohalogens, halogens, an effective amount of a microorganism oxidizing agent selected from diperoxyorganic acid, dioxides monopersulfates, halogens, perborate-releasing compounds, peroxides, percarbonates, persulfates, permanganates, ozone and mixtures thereof; and (ii) a microbiocidally effective amount of microbiocide to inhibit the growth of microorganisms selected from glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decylthio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitroethyl) furan, poly (oxyethylene (dimethylimino) ethylene (dimethylimino) ethylene dichloride), alkyldimethylbenzylammonium chloride, alkylamidopropylpropylene glycol, dimethalammonium chloride phosphate,

2., 4,4'-tri-chloro-2'-hydroxydiphenyl ether, tetrakis-hydroxylmethylphosphonium sulfate, tributyltetradecylphosphonium chloride, 2-bromo

2-nitropropane-1,3-diol, 2 ', 2-dibromo-2-nitroethanol and sanquino-riaextract -------. ----------- —_____. _ _

The present invention is directed to some novel biocidal compositions comprising a combination of oxidizing agents and non-oxidizing biocides that are added to the aqueous system in amounts effective to inhibit and control the growth of microorganisms in the aqueous system.

The biocidal compositions of the invention comprise (i) microbiocidally to inhibit growth comprising a mono-effective amount of a microorganism oxidizing agent selected from diperoxyorganic acid, halogen dioxides, monopersulfates, halogens, halogen-releasing compounds, perborates, peroxides, percarbonates, persulfates, permanganates, ozone and their and (ii) a microbiocidally effective amount of microbiocide to inhibit the growth of microorganisms selected from glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decyl-thio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitroethyl) furan, poly (oxyethylene (dimethylimino) ethylene (dimethylamino) ethylenedichloride), alkyldimethylbenzylammonium chloride, alkylamidopropylpropylene glycol, dimethalammonium chloride phosphate, 2,4,4'-trichloro-2'-hydroxydiphenyl ether, tetrakis-hydroxylmethylphosphonium trisodium phosphonium phosphate, bromo-2-nitropropane-1,3-diol, 2,2-dibromo-2-nitroethanol and sanqui nariaextrakt.

(iii) a surfactant / dispersant, (iv) an anti-corrosive agent, and (v) an anti-scale agent.

The oxidizing agents and non-oxidizing microbiocides of the invention are commercially available or can be readily synthesized from commercially available raw materials by known methods.

Suitable peroxides include inorganic peroxides such as hydrogen peroxide, sodium peroxide, and organic peroxides such as benzoyl peroxide. Suitable halogen-releasing compounds are hydantoins such as 1,3-dichloro-5,5-dimethylhydantoin, 1,3-dibromo-5, 5-dimethylhydantoin or 1,3-diiodo-5,5-dimethylhydantoin Suitable mono- or di- peroxyorganic acids include, but are not limited to, perbenzoic acid, peroxypropionic acid, hexane piperoxoic acid, dodecane piperoxoic acid. Suitable halogenated dioxides are sulfur dioxide, bromine dioxide and iodine dioxide. Specific examples of other suitable oxidizing agents are sodium perborate, sodium percarbonate, potassium permanganate, sodium persulfate, chlorine, bromine, iodine and compounds releasing chlorine, bromine and iodine, sodium monopersulfate, potassium monopersulfate, and ammonium monopercarbonate. A preferred oxidizing agent is potassium monopersulfate (commercially available as OXONE and DuPont),

Surprisingly, this combination of said oxidizing agents and non-oxidizing biocides provides an improved biocidal activity that is greater than the sum of the individual components of the compositions. The microbiocidal compositions of the present invention have a high degree of mucosal activity which could not be predicted from the known activities of the individual components forming the combination. The improved biocidal activity of the compositions of the invention is particularly surprising since not all oxidizing agents provide improved biocidal activity when combined with non-oxidizing biocides. In fact, some oxidizing agents are antagonistic when used with non-oxidizing biocides and result in lower biocidal activity than using each component alone.

The biocidal combinations of the present invention effectively control growth and prevent the growth and reproduction of microorganisms, for example, in water cooling systems in paper mill systems and in pulp mills in oil operations (eg oil wells), industrial lubricants and refrigerants, bays, lakes and in ponds. The particular type of microorganism present in these regions varies locally and even varies at a given location with time. Representative examples of microorganisms that can be effectively combated with the biocidal compositions of the invention include fungi, bacteria and algae, and particularly include species such as Aspergillus, Penicillium, Candida, Saccharomyces, Aerobacter, Escherichia, Alcaligenes, Bacillus, Chlorella, Spirogyra, Oselalatoria, Vaucheria , Pseudomonas, Salmonella, Staphylococcus, Pullularia, Flavobacterium, and Rhizopus.

According to the invention, the aqueous system is treated to prevent the growth of microorganisms by adding at least one oxidizing agent and at least one non-oxidizing microbiocide. These components are present in the system simultaneously. While oxidizing agents and a non-oxidizing biocide may be combined, it is generally preferred not to combine the microbiocide with the oxidizing agent too early before addition to the aqueous system, since these materials may be deleterious when brought into direct contact with each other in their concentrated form.

Dosage amounts of the oxidizing agent and non-oxidizing microbiocide added to the aqueous system can vary widely depending upon the nature of the aqueous system being treated, the degree of organism present in the aqueous system, and the degree of inhibition desired. When dosing the oxidizing agents of the invention, an important consideration is the content of, for example, iron (II), reduced manganese, sulfide, ammonia, and organic substances that can react and thus consume the oxidizing agents of the invention. The term oxidant consumption refers to the difference between the amount of oxidant dosed and the residual oxidant concentration after the prescribed contact time, pH and temperature. The term Oxidant Requirement means the metered amount of oxidizing agent required to achieve a given residual concentration at a prescribed contact time, pH and temperature.

Since the contents of, for example, divalent iron, reduced manganese and sulphide can vary within wide limits in different systems, the consumption of oxidizing agent for the aqueous system to be treated should be determined by the method of the invention. For purposes of the invention, the dosed amount of oxidizing agent added to the aqueous system, i.e. the biocidally effective amount, corresponds to the concentration of residual oxidizing agent in the aqueous system. The residual concentration of oxidizing agent is readily ascertained by one of ordinary skill in the art.

The dosage amount of the oxidizing agent may generally be 0.1 ppm to 100 ppm, preferably about 0.5 ppm to about 45 ppm. The dosage amount of the non-oxidizing microbiocide in the system may be 0.1 ppm to 125 ppm, preferably about 0.5 ppm up to about 45 ppm. When microbiocides and oxidizing agents are present in the indicated amounts, the resulting combination has a higher degree of activity against microorganisms than the individual constituents of the combination. While more microbiocides or oxidizing agents can be used without detrimental effects, they increase treatment costs and generally provide little additional preference.

The microbiocidal compositions of the present invention may be used. used in combination with one or more surfactants / dispersants to disperse biomass and to improve the dispersibility and stability of these microbiocidal compositions. Suitable surfactants / dispersants include, but are not limited to, cationic, anionic or amphoteric surfactants and polymers such as fluorinated surfactants, alkylaryl polyether alcohols, polyether alcohols, sodium dodecylsulfate, sodium nonylbenzene sulfonate, sodium dioctylsulfosulfate, sodium octyl polyoxyethylene sulfonate, sodium octyl polyoxyethylene sulfonate, sodium polyoxyethylene sulfonate. with long-chain alcohols, mercaptans, amines, carboxylic acids, sodium sulphonate or condensed naphthalene-formaldehyde and lignin sulphonate, alkylbenzene sulphonates and sulphates, linear dodecylbenzene9 sulphonate, propylene oxide / ethyleoxide block copolymers, such as polyoxypropylene glycol polymers of 1500 to 2000 molecular weight up to 30% ethylene oxide (a commercial product of Pluronic and Tetronic, BASF surfactants) and the like. Suitable fluorinated surfactants include those manufactured by 3M such as FC-99, FC-100 and FC-129. FC-99 is an anionic surfactant that is a 25% active solution of aminoperfluoroalkyl sulfonate in water. FC-100 is an amphoteric surfactant that is a 28% active solution of a solid fluorine surfactant in a glycol / water system. FC-129 is an anionic surfactant that is a 50% solution of fluorinated potassium alkylcarboxylate in water, in butyl cellulose and ethanol. The dosage amount of surfactant / dispersant in the aqueous system is not in itself critical, provided that it is added in an amount effective to disperse the biomass or to stabilize the respective microbiocidal composition. These dosages are generally 0.5 to 500 ppm.

The biocidal compositions of the invention may also be combined with an anticorrosive material. Suitable anticorrosive materials include, but are not limited to, phosphates such as sodium tripolyphosphate, tetrasodium pyrophosphate, phosphonates, and carboxylates. These components may be added to help protect the mild steel from corrosive attack by the oxidizing agent. The anti-corrosive material may be mixed with the oxidizing agent prior to addition to the system, or may be added separately. Typically, the anti-corrosive material is added to the system in an amount of 0.5 to 50% based on the total amount of the mixture of oxidizing agent and the anti-corrosive material. More preferably, the amount of anticorrosive material is at least 1% of the total amount of the oxidizing agent / anticorrosive material mixture.

The biocidal compositions of the invention may also be used in combination with other biocides that further enhance synergistic action. Suitable biocidal combinations include, for example, glutaraldehyde with isothiazolone. The ratio of these biocidal combinations may be 1:10 to 10: 1 by weight. A preferred isothiazolone is a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one.

The biocidal compositions of the invention may also be used in combination with a scaling agent. Suitable anti-scaling materials include, for example, polyacrylates such as sodium polyacrylate, phosphonates such as hydroxyethylidene phosphonic acid, and the like. The anti-scaling material is usually added to the system in an amount of 0.5 to 50% based on the total amount of oxidizing agent / anti-scaling material mixture.

The oxidizing agents of the invention may be in a solid or liquid state and may be diluted with a solid or liquid carrier. Powders may be prepared with finely divided solid carriers including talc, clay, pyrophyllite, diatomaceous earth, hydrated silica, calcium silicate or magnesium carbonate. The powders may typically contain 1 to 15% of the microbiocides of the invention, while a wettable powder may be obtained by increasing the microbiocide content to about 50 or more percent. A typical example of a wettable powder is a mixture of 20 to 50% of suitable compounds of the invention 45 to 75% of one or more finely divided solid particles, 1 to 5% of a wetting agent, and 1 to 5% of a dispersant.

The oxidizing agents according to the invention can also be used in the form of liquid concentrates. Such concentrates are prepared by diluting or dissolving the oxidizing agents and / or microbiocides of the invention in a solvent together with one or more surfactants.

The invention is illustrated, but not limited, by the following examples. Unless otherwise indicated, percentages are by weight.

The synergism of the two-component microbiocidal combinations of the present invention is demonstrated by testing a wide range of concentrations and ratio of components, at two serial dilutions in liquid. The fluid consists of deionized water supplemented with inorganic components to mimic industrial water. The work is carried out with bacterial Enterobacter aerogens or with a mixed culture of bacteria consisting of Enterobacter aerogens, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis; Aspergillus niger fungi and Chlorella vulgaris or Scenendesmus quadracauda. All organisms are typical representatives of organisms found in industrial waters. The contact time is 2 to 24 hours and incubation on the agar surface takes place at temperatures, times and illumination allowing growth of visible colonies. The agar surface for bacteria is Trypcic Soy, for algae CHU-10 and for fungi yeast extract potato dextrose. During the tests are. carry out a uniform vaccination of the imitated industrial waters so that all test solutions and all exposures of organisms are carried out at the same organism density per milliliter. After inoculation of imitated industrial waters, these cell densities are thousands per ml for fungal spores and alg and millions per ml for bacteria. After contacting the bacteria-biocide in the liquid medium and the agar subculture, organic nutrition is added to each tube or well of the bioassay in the form of sterile tryptic soybean, followed by re-incubation to determine the viability of all surviving organisms expressed as turbidity (growth). There is no growth in clear medium without turbidity.

A 90 to 100% reduction is used to calculate the synergy compared to the untreated control samples of the different colony-forming states.

Test results demonstrating the synergy of biocidal combinations are shown in the following examples.

Each table in the examples shows the synergy expressed as (1) the concentration of each test material acting alone needed to produce a given final state of preventing growth or inhibiting colony formation compared to untreated control samples and (2) as lower required concentrations of the combined test materials.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

This example shows the synergy between glutaraldehyde and hydrogen peroxide using Enterobacter aerogenes and a mixed bacterial culture.

Table I

Active biocide concentration to achieve 100X inhibition of Enterobacter aerogenes at four hour contact

Glutaraldehyde mg / l, H2O2mg / l

0

200.0

6.3

Table II

Active concentration of biocide to achieve 100X inhibition of four mixed bacterial species at four hour contact

Glutaraldehyde mg / l H2O2mg / l 100 ALIGN! 0 0 100.0 3.8 50.0 7.5 25.0 15.0 '’* -” 3.1 ”*

Example 2

This example shows the synergy between glutaraldehyde and hydrogen peroxide using green algae Clorella vulgaris and Scenedesmus quadracauda

Table III

Active biocide concentration to achieve 100% inhibition of Clorella vulgaris and unknown Ancillary Bacteria at 23 hour contact

Glutaraldehyde mg / _{1_:} _ H202mg / l> 320 0

40

20 May

Table IV

Active biocide concentration to achieve 100% inhibition of Scenedesmus quadracaud at 4 hour contact

Glutaraldehyde mg / l_H2O2mg / l

0

40

5

Example 3

The data in Table V indicate the synergistic action of hydrogen peroxide in combination with glutaraldehyde and Kathon 886F (4: 1 active ingredient) using green algae Clorella vulgaris. Kathon 886F is a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and a

2-methyl-4-isothiazolin-3-one.

Table V

Active concentration of biocide to achieve 100% inhibition of Clorella vulgaris at 2 hour contact

Glutaraldehyde mg / i_H20zmg / l

416. O

O 100.0

104 6,3

12.5

Example 4

This example illustrates the synergy between limonene and oxygenating biocides using a mixture of four bacterial species.

Table VI

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

d-Limonene mg / l H2O2mg / l Peracetic acid mg / l > 2000 0 0 0 300 0 0 0 23.5 ³¹ 75 0 31 0 11.8 Example 5 This example shows synergy between 2- (decylthio) ethane-

amine (DTEA) and an oxygenating biocide hydrogen peroxide using a mixed culture of bacteria.

Table VII

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on Four hour contact

DTEA mg / l_H2O2mg / l

100 ALIGN!

O

- -25

100.0

3.1

Example 6

This example shows the synergy between 2,2-dibromo-2-nitroethanol and the oxygenating biocide hydrogen peroxide.

Table VIII

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

2,2-Dibromo-2-nitroethanol mg / lH2O2mg / l

7.8 0> 200.0

3.9 3,1

Example 7

This example demonstrates the synergy between poly (oxyetbylene (dimethylimino) ethylene (dimethylimino) ethylene dichloride) (WSCP) and the oxygenating biocide hydrogen peroxide, using bacterium Enterobacter aerogenes as the test organism.

Table IX

Active concentration of biocide to achieve 100% inhibition

Enterobacter aerogenes at 4 hour contact WSCP mg / l - H 2 O 2 mg / l

0

30

5

Example 8

This example shows the synergy between tetradecyldimethylbenzylammonium chloride and the oxygenating biocide hydrogen peroxide.

Table X

Active concentration of biocide to achieve 100% inhibition

Enterobacter aerogenes at four-hour contact Tetradecyldimethylbenzylammonium chloride mg / l H2O2ing / l 20 May 0 0 100 ALIGN! 2.5 20 May 5.0 10

Example 9

This example shows the synergy between tetrakishydroxymethylEosphonium sulfate and hydrogen peroxide.

Table XI

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

Tetrakishydroxymethyl phosphonium sulphate mg / lH 2 Q 2 mg / l

31.2 0 O 100

15,6 50

Example 10

This example shows the synergy between tributyltetradecylphosphonium chloride and hydrogen peroxide.

Table XII

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

Tributyltetradecylphosphonium chloride mg / l_H202mg / l

31,3 0

200.0. 7 »8 _____ .3.1

Example 11

This example shows the synergy between 2-bromo-2-nitropropane

1,3-diol and hydrogen peroxide.

Table XIII

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

2-Bromo-2-nitropropane-1,3-diol mg / l_H2O2mg / l

62.5 0

100.0

7.8 25.0

15.6 6,3

Example 12

This example illustrates the synergy between cocamidopropylpropylene glycol dimethylammonium phosphate and hydrogen peroxide.

Table XIV

Active concentration of biocide to achieve 100% inhibition of Enterobacter aerogenes at two hour contact.

Cocamidopropylpropylene glycol dimethylaminoDonium chloride phosphate mg / 1_H2O2mg / l

0

200.0

2.5

Example 13

This example shows the synergy between 2,4,4'-trichloro-2'hydroxydiphenyl ether and hydrogen peroxide,

Table XV

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

2,4,4 ', - triclor- ^2H -hydroxy-diphenyl ether mg / 1HZOmg / l

500.0 0

150

31,2 75

Example 14

The data in Table VI show the synergy of hydrogen peroxide with the sanquinium extract against a mixed culture of bacteria.

Table XVI

Active biocide concentration of four bacterial species at

Sanquinaria extract to achieve 100% inhibition of the four hour contact mixture mg / l_H2O2mg / L

31.2

3.9

7.8

200.0 25.0

3.1

Example 15

This example shows the synergy between poly (oxyethylene (dimethylamino) ethylene (dimethylimino) ethylene dichloride) (WSCP potassium monopersulfate).

Table XVII

Active concentration of biocide to achieve 99.93% inhibition of mixture of four bacterial species on 15-hour contact

WSCP mg / l_Monopersulphate mg / l

0 ______________ 0 ... __________________.> 4.0- ______8 0.5

- 19 19;

Example 16

This example shows the synergy between glutaraldehyde and sodium hypochlorite.

Table XVIII

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on four-hour contact

Glutaraldehyde mg / l Sodium hypochlorite mg / l 25 0 0 > 1 12.5 0.016

Example 17

This example shows the synergy between glutaraldehyde and bromine.

Table XIX

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on two-hour contact

Glutaraldehyde mg / l Bromine mg / l

0

1,000

3.1 0.125

Example 18

Experimental results (Table XX) show the synergy of peracetic acid with glutaraldehyde using a mixture of bacteria.

Table XX

Active concentration of biocide to achieve 100% inhibition of a mixture of four bacterial species on two-hour contact.

Glutaraldehyde mg / l 50.0 0

6,3 peracetic acid mg / l

25.0

6.3

Example 19

Other combinations showing synergy of microbiocidal activity are:

(1) bis (trichloromethyl) sulfone and potassium carbonate, (2) dodecylguanidine hydrochloride and sodium perborate, (3) 2- (2-bromo-2-nitroethyl) furan and ozone, (4) glutaraldehyde and potassium permanganate, (5) (6) tributyltetradecylphosphonium chloride and sodium persulfate, (7) bis (trichloromethyl) sulfone and diperoxydodecanoic acid, (8) d-limonene, hydrogen peroxide and peracetic acid, (9) glutaraldehyde, sodium peroxide and nonylbenzene (10) Glutaraldehyde, peracetic acid and polyoxypropylene glycol polymer, molecular weight 1650, reacted with 25% by weight ethylene oxide (a commercial product of Plurinic)

(11) d-limonene, hydrogen peroxide and sodium dioctylsulfosuccinate.

Example 20

In this example, 4,5-dichloro-1,2-dithiol-3-one (Dithiol) is evaluated under experimental conditions and there is no synergy in inhibition between dithiol and hydrogen peroxide. The results in Table XXI show no synergy but very strong antagonism between the two test materials, suggesting that not all microbiocides can be combined with an oxidizing agent to control the growth and deposition of slime-forming microorganisms in water,

Table XXI

Survival of colony-forming units on tryptic soybean agar after four hours exposure to a combination of hydrogen peroxide and dithiol

Mixture of four kinds of bacteria

Processing - Number surviving colony forming units Dithiol 15.6 ppm 0 Dithiol 15.6 ppm + • H2O2 25 ppm > 2 X 106 Dithiol 62.5 ppm + H2O2 25 ppm > 2 X 10 ^ H2O2 25 ppm > 2 X 10 *

Industrial applicability

Microbiocidal compositions and processes utilizing these microbiocidal compositions for inhi. whips for the growth of microorganisms in aqueous systems. In particular, microbiocidal compositions based on a synergistic mixture of (i) an oxidant and (ii) a non-oxidizing agent; microbiocide optionally with a surfactant / dispersant and a non-corrosive agent and / or a scaling agent.

- 28 / He / she will have the nationality of his / her research-tbprarv-e-n ^

Claims (9)

PATENT CLAIMS 1. A synergistic biocidal mixture comprising: (i) microbiocides to inhibit growth comprising an effective amount of a microorganism oxidizing agent selected from the group consisting of a diperoxyorganic acid, halogen dioxides, monopersulfates, halogens, halogen-releasing compounds, perborates, peroxides, percarbonates, persulfates, permanganates, ozone and mixtures thereof; ii) a microbiocidally effective amount of a microbiocide for inhibiting the growth of microorganisms selected from glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decylthio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitroethyl) furan, poly (oxyethylene (dimethylimino) (ethylene (dimethylimino) ethylene di chloride), alkyldimethylbenzylammonium chloride, alkylamidopropylpropylene glycol, dimethalammonium chloride phosphate, 2,4,4'-trichloro-2'-hydroxydiphenyl ether, tetrakis-hydroxylmethyiphosphonium sulphate, tributyltetradecyl 2-nitrophosphonium 2-phosphonium 2-phosphonium 2-phosphonium 2-phosphonium , 2,2-dibromo-2-nitroethanol and sanquinariaextrakt. 2. A method for controlling or inhibiting microbial growth in aqueous systems, comprising adding (i) microbiocidally to the system an effective amount of a microorganism oxidizing agent selected from the group consisting of mono- and diperoxyorganic acids, halogen dioxides, monopersulfates, halogens halogen-releasing compounds, perborates, peroxides, percarbonates, persulfates, permanganates, ozone and mixtures thereof; and (ii) a microbiocidally effective amount of microbiocide to inhibit the growth of microorganisms selected from glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decylthio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitroethyl) furan, poly (oxyethylene (dimethylimino) ethylene (dimethylimino) ethylenedichloride), alkyldimethylbenzylammonium chloride, alkylamidopropylpropylene glycol, diBethalammonium chloride trisphosphate, 2,4'-triethylammonium phosphate -2'-hydroxydiphenyl ether, tetrakis-hydroxylmethylEosphonium sulphate, tributy 1-tetradecylphosphonium chloride, 2-bromo-2-nitropropane-1,3-diol, 2,2-dibromo-2-nitroethanol and sanquinariaextrakt. 3. The method of claim 2 wherein the aqueous system is an aqueous papermaking and pulp mill system. 4. The method of claim 2 wherein the microorganisms are a bacteria-reducing sulfate and the aqueous system is an oil processing system. 5. The method of claim 2 wherein the microorganisms are algae, bacteria, and fungi. 6. The method of claim 5, wherein the aqueous system is a water cooling system. 7. A method of controlling and inhibiting the growth and deposition of mucus-forming microorganisms in water, comprising adding (i) a microbiocidally effective amount of an oxidizing agent or an oxidizing biocide to inhibit the growth of microorganisms selected from the group consisting of perborates, peroxides and percarbonates; (ii) a microbiocidally effective amount of a microbiocide to inhibit the growth of microorganisms selected from the group consisting of glutaraldehyde and a combination of glutaraldehyde, 5-chloro-2-methyl-4-iso30 thiazolin-3-one and 2-methyl-4-isothiazolin-3-one . The method according to claim 8, characterized in that at least 10 parts by weight of microbiocide and 90 parts by weight of oxidizing agent are used up to 90 parts by weight of microbiocide and 10 parts by weight of oxidizing agent. 11. A synergistic biocidal mixture comprising: (i) a microbiocidally effective amount of an oxidant for inhibiting the growth of microorganisms selected from the group consisting of monopersulfates halogens, halogen releasing compounds, perborates, peroxides, percarbonates, peroxyorganické acid, chlorine dioxide, persulfates, diperoxy dodecanoic acid, permanganates, ozone and mixtures thereof, and ^{(ii (iii)} (ii) a microbiocidally effective amount of microbiocide for inhibiting the growth of microorganisms selected from the group consisting of glutaraldehyde, limonene, bis (trichloromethyl) sulfone, 2- (decylthio) ethanamine, dodecylguanidine hydrochloride, 2- (2-bromo-2-nitrite) roethyl ⁱ⁾ furan, poly (oxyethylene (dimethyliminio) ethylene '(dimethylamino hy1imi ~ no) ethylendichlor id}, alkylene Idimethylbe.nzy lamoniumchlor ID alkylamidopropylpropylenglykol, dimethalamoniumchloridfosfát, 2,4,4''trichloro-2'-hydroxydiphenyl ether, tetrakis-hydroxylmethylphosphonium sulfate, tributyltetradecylphosphonium chloride, 2-bromo 2-nitropropane-1,3-diol, 2,2-dibromo-2-nitroethanol and sanquinariaextract and (iii) surfactant / dispersant 10. A synergistic biocidal composition according to claim 11, which comprises 0.5 to 45 ppm of an oxidizing agent and 0.5 to 45 ppm of a microbiocide.