Slime control compositions containing phenolic compounds and their use
United States Patent [1 1 Brink, Jr. et al.  
 [451 Apr. 8, 1975 1 SLIME CONTROL COMPOSITIONS CONTAINING PIIENOLIC COMPOUNDS AND THEIR USE [75] Inventors: Robert H. Brink, Jr., Doylestown;  
  Bernard F. Shema, Glenside; Roger L. Justice, Cornwells Heights; Paul Swered, Philadelphia, all of Pa.  
  Related U.S. Application Data [62] Division of Ser. No. 160,191, July 6, 1971, Pat. No.  
 [52] U.S. C1. 424/277; 71/67; 162/190; 424/346 [51] Int. Cl A0ln 9/02 [58] Field of Search 71/67; 424/277, 346  
 [56] References Cited UNlTED STATES PATENTS 2,997.380 8/1961 Josephs 71/66 3,031,372 4/1962 Brock 424/277 3,824,318 7/1974 Shema et a1. 71/67 3,829,305 8/1974 Brink, Jr. et a1. 71/67 Primary E.\&#39;aniiner.1ames 0. Thomas, Jr. Attorney, Agent, or FirmAlexander D. Ricci [57] ABSTRACT The present invention relates to certain processes and compositions useful for inhibiting and/or controlling the growth of slime in water and, in particular, water employed for industrial purposes. Water employed in the manufacture of pulp paper and water employed in cooling water systems, as well as other industrial waters, provide environments which are conducive to slime formation. The novel compositions of the present invention are mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems. The slime, of course, is objectionable from an operational and/or an aesthetic point of view. Specifically, the invention is directed to and the use of compositions-comprising a combination of 5- chloro-4-phenyl-1,2-dithiole-3-one and phenolic compounds (or mixtures thereof). The inventive compositions inhibit the growth of slime in water, or more specifically, possess biocidal activity against bacteria,  
 fungi and/or algae. The phenolic compounds contem-&#39; plated for use in accordance with the present invention are those phenolic compounds which possess the capacity to kill or inhibit the growth of slime-forming microorganisms such as bacteria, fungi and algae. The type phenolic compounds encompassed by the present invention may be exemplified by: phenol, orthophenylphenol, 2, 3, 4, 6-tetrachlorophenol, 4-ch1oro- 2-cyclopentylphenol and 2-chloro-4-phenylphenol.  
 5 Claims, N0 Drawings SLIME CONTROL COMPOSITIONS CONTAINING PHENOLIC COMPOUNDS AND THEIR USE This is a continuation, division, of application Ser. No. 160,191, filed July 6, 1971 now U.S. Pat. No. 3,829,305.  
 BACKGROUND OF THE INVENTION The formationof slime by microorganisms is a problem which attends many systems. For example, lagoons, lakes, ponds, pools and such systems as cooling water systems and pulp and paper mill systems all possess conditions which are conducive to the growth and reproduction of slime-forming microorganisms. In both once-through and recirculating cooling systems, for example, which employ large quantities of water as a cooling medium, the formation of slime by microorganisms is an extensive and constant problem.  
  Airborne organisms are readily entrained in the water from cooling towers and find this warm medium an&#39; ideal environment for growth and multiplication. Aerobic and heliotropic organisms flourish on the tower proper while other organisms colonize and grow in such areas as the tower sump and the piping and passages of the cooling system. Such slime serves to deteriorate the tower structure in the case of wooden towers. In addition, the deposition of slime on metal surfaces promotes corrosion. Furthermore, slime carried through the cooling system plugs and fouls lines, valves, strainers, etc. and deposits on heat exchange surfaces. In the latter case, the impedance of heat transfer can greatly reduce the efficiency of the cooling system.  
  In pulp and paper mill systems, slime formed by microorganisms is also frequently and, in fact, commonly encountered. Fouling or plugging by slime also occurs in the case of pulp and paper mill systems. Of greater significance, the slime becomes entrainedin the paper produced to cause breakouts on the paper machines with consequent work stoppages and the loss of production time or unsightly blemishes in the final product; this, of course, results in rejects and wasted output. The previously discussed problems have resulted in the extensive utilization of biocides in cooling water and pulp and paper mill systems. Materials which have enjoyed widespread use in such applications include chlorine, organo-mercurials, chlorinated phenols, organobromines, and various organo-sulfur compounds. All of these compounds are generally useful for this purpose but each is attended by a variety of impediments. For example, chlorination is limited both by its specific toxicity for slime-forming organisms at economic levels and by the ability of chlorine to react which results in the expenditure of the chlorine before its full biocidal function may be achieved. Other biocides are attended by high costs, odor problems and hazards in respect to storage, use or handling which limit their utility. To date, no one compound or type of compound has achieved a clearly established predominance in respect to the applications discussed. Likewise, lagoons, ponds, lakes and even pools, either used for pleasure purposes or used for industrial purposes for the disposal and storage of industrial wastes become, during the warm weather, besieged by slime due to microoraganism growth and reproduction. In the case of the recreational areas, the problem of infection, odor, etc. is obvious. In the case of industrial storage or disposal of industrial materials, the microorganisms cause additional problems which must be eliminated prior to the materials use or the waste is treated for disposal.  
  It is the object of the present invention to provide compositions for controlling slime-forming microorganisms in aqueous systems, such as cooling water systems and pulp and paper mill systems, and for controlling slime formation or microorganism populations in aqueous bodies ingeneral. Moreover, another object of the invention is the provision of methods for preserving materials and for controlling slime-forming microorganisms in any aqueous system which is conducive to the growth and reproduction of microorganisms and, in particular, cooling water and paper and pulp mill systems. These methods employ a combination of 5- chloro-4-phenyl-1,2-dithiole-3-one and a phenolic compound (or mixtures thereof). The phenolic compound must possess the property of being biocidally active against bacteria, fungi and/or algae, i.e., either kill or inhibit the growth of these microorganisms.  
  In the practice of the invention, the combination is added to the particular material to be preserved or to the system being treated, for example cooling water sytems, paper and pulp mill systems, pools, ponds, lagoons, lakes, etc., in a quantity adequate to control the slime-forming microorganisms which are contained by, or which may become entrained in, the system which is treated. It has been found that such compositions and methods control the growth and occurrence of such microorganisms as may populate these particular systems.  
 GENERAL DESCRIPTION OF THE INVENTION As earlier stated, the inventive compositions comprise a combination of 5-chloro-4-phenyl-1,2-dithiole- 3-one and a particular phenolic compound (or mixtures thereof) with either compound being present in such a quantity as to impart a synergistic behavior for the purpose to the composition as a whole. Preferably, the compositions contain a percentage by weight ranging from about 5 to about percent of the dithiole- 3-one compound and from about 5 to about 95 percent of the phenolic compound. When these two ingredients are mixed either beforehand or by addition to the aqueous system individually, the resulting mixtures possess a high degree of slimicidal activity which could not have been predicted beforehand from the known activity of the individual ingredients comprising the mixture. Accordingly, it is therefore possible to produce a more effective slime-control agent than has previously been available. Because of the enhanced activity of the mixture, the total quantity of biocide required for an effective treatment may be reduced. In addition, the high degree of biocidal effectiveness which is provided by each of the ingredients may be exploited without use of the higher concentrations of each. This feature is not only important and advantageous from an economical point of view, but also most desirable from the pollution or ecological standpoints. In this regard, it might be pointed out that the smaller the amount of a chemical that is required for effective treatment, the smaller the problem in treating the wastes from these systems. In both cooling water systems and in paper and pulp mill systems, certain discharge of waste water, e.g., blowdown in cooling water systems, is a necessity. However, because of the current concern and legislation regarding the discharge of wastes, the effluent waste water must be treated to reduce and, hopefully, to eliminate any undesirable constituents. This treatment, of course, is time consuming and costly. Accordingly, a reduction in additive usage will result in a corresponding reduction in costs for the treatment of wastes containing these additives.  
  To demonstrate the synergism which is obtainable from the combination of the phenolic compounds with the 5-chloro-4-phenyl-l,2-dithiole-3-one (supplied by Hercules Corporation under designation S-l6l2), various exemplary phenolic compounds were chosen. As earlier indicated, synergistic activity can be obtained by combining the dithiole-3-one compound with phenolic compounds which exhibit growth inhibitory or biocidal activity with respect to bacteria, fungi and/or algae. The phenolic compounds which were chosen as representative are as follows: phenol, orthophenylphenol (Dow Chemical Dowicide I); 2-chloro- 4-phenylphenol (Dowicide 4); 2, 3, 4, 6- tetrachlorophenol (Dowicide 6); and 4-chloro-2- cyclopentylphenol.  
  In order to illustrate the synergistic activity, the efficacy and the comparative effectiveness ofthe inventive compositions, various tests were utilized and will be described following.  
 growth was determined by turbidity or clarity respectively in the medium. End points for the various mixtures were then compared with end points for the pure active ingredients working alone in concomitantly prepared culture bottles. Synergism was determined by the method described by Kull et al., [F. C. Kull, P. C. Eisman, H. D. Sylwestrowicz and R. L. Mayer, Applied Microbiology, 9, 538-41, (1961 )]and the relationships, QA/Qu Q /Q 1 is additivity I is antagonism Where, I IS synergism TABLE l Weight Ratio Quantities Producing End Points (ppm) Q, Q of A to B Q, Q Mixture Q IQ Qn/QlI Q&#34; Q.  
 100/0 14 (Q0) 95/5 10.45 0.55 l 1.0 0.747 0.0003 0.75 50/50 10.0 10.0 20.0 0.714 0.005 0.72 5/95 9.0 171 180 0.643 0.086 0.73 0/ l 00 2000(Q SPECIFIC EMBODIMENTS It is evident from the data recorded in Table I that EXAMPLE I SYNERGISTIC COMBINATION:  
 Compound A: 5-chloro-4-phenyl-l,2-dithiole-3-one Compound B: Phenol The compositions of this Example contained 5-chloro-4-phenyl-l,2dithiole-3-one (referred to as Compound A in the Test Equations and in Tables I through 1C and phenol (referred to as Compound B in this Example and in the Test Equations and in Tables 1 through 1C) in the weight ratios expressed in the Tables which follow. The compositions were tested for synergistic activity in accordance with the method described. The synergism test was utilized to evaluate each of the combinations of this Example and the following Examples. Synergistic Index Test 7 Synergistic activity was demonstrated by ading Compound A and Compound B in varying ratios and over a range of concentrations to liquid nutrient medium which was subsequently inoculated with a standard volume of suspension of the bacterium Aerobacter aerogenes. Following 2 days incubation, the lowest concentration of each ratio which prevented growth of the bacteria was taken as the end point. Growth or nocompositions of the present invention function to control slime growth due to microorganisms not only at equal portions of the respective ingredients, but also where just minor amounts of one or the other are present. This discovery of synergism at the lower levels is extremely valuable since it illustrates conclusively that the ingredients are compatible over the wide percentage by weight range.  
 BACTERICIDAL EFFECTIVENESS The bactericidal effectiveness of the mixture of Compound A and Compound B of this Example is demonstrated by the following Table in which the inhibiting power of a 50/50 by weight mixture of A and B is shown. Aerobacter aerogenes was employed as the test organism and a substrate technique was utilized. Specifically, the biocidal mixture was added in gradually increasing quantities to nutrient agar media which was then inoculated with A. aerogenes. The preparation was then incubated for 48 hours. The values set forth in the Table indicate the quantity of biocide required, in parts by weight for each one million parts by weight of the medium, in order to achieve complete inhibition of the growth of the test organism.  
 TABLE IA Biocidal Material Compound A (571 Compound B (S /1). Inert FUNGICIDAL EFFECTIVENESS In order to test the effectiveness of the inventive rnixtures in respect to fungi. evaluations were made following the procedures described by B. F. Shema and J. H. Conkey [Journal for the Technical Association of The Pulp and Paper Industry, 36, 20A-30A, (1953)]. The described procedure generally entails incorporating the biocide under test in a nutrient substrate such as agar, malt, etc. and pouring the resulting medium into a Petri dish and allowing the medium to solidify. A button of fungus inoculum is placed on the surface of the solidified medium and the medium is incubated for a period of l4 days. After the period, the diameter of the colony is measured and compared with the diameter of the button of inoculum originally placed upon the surface. If there is no increase in the diameter, the growth of the fungus is&#39;considered to be completely inhibited and the treatment level which accomplished this is considered the inhibitory concentration. The fungal species utilized as the test microorganism to evaluate the efficacy of the present mixture were Penicillium expansum and Aspergillus niger.  
 TABLE I8 percentage kill (based on the initial control count) may be calculated. In this evaluation the water sample was taken from a water tray of a paper machine located in the northeastern United States.  
  For the purposes of comparison, the mixture of A and B was evaluated together with two recognized commercial biocides, Pentachlorophenol and a Commercial Product.  
  A perusal of the recorded percentages clearly establishes that the composition of the present invention, although less concentrated with respect to active ingredients as compared to the two commercial products, gave excellent rates of kill even at low treatment levels. As earlier expressed, excellent performance of a biocidal composition at low treatment levels not only provides a most desirable cost performance index, but also provides most desirable advantages from theaspects of Quantity (ppm) for inhibition Biocidal Material P. expansmn A. niger Compound A (5% Compound B (5%), Inert (90%) 100 100 TABLE IC Quantity of Percent kill Biocidal Material biocide (ppm) after 6 hours Compound A (5%). Compound B (S /1). Inert (90%) 5 77 do. do. do. 10 89 do. do do. 25 94 do. do. do. 50 99 do. do. do. 100 100 Pentachlorophenol (10091) 5 82 do. 10 9] do. 25 100 do. 50 100 do. 100 100 Commercial Product active: Combination of dithiocarbamates) 5 72 do. do. 10 72 do. do. 25 73 do. do. 78 do. do. 100 88 SLIME CONTROL EFFECTIVENESS The inventivemethods and compositions were also tested with respect to theirperformance in the control of slime formation in industrial systems. In this test an industrial recirculating water was obtained from a system which was currently experiencing problems in respect to the formation of slime by microorganisms. Such tests do not demonstrate the efficiency of the biocide employed with respect to specific species of microorganisms but instead supply a practical demonstration of the efficacy of the biocide tested in relation to those communities of microorganisms which have evidenced their ability to form slime in actual industrial systems.  
 In the testing of recirculating water samples, a sub strate evaluation was employed. ln&#39;such testing identical portions of water samples are treated with varying pollution abatement, waste treatment costs and the preservation of the ecological strain.  
 EXAMPLE 2 For mixtures of Compounds A and B, and for Cornpound A and Compound B acting alone, the following results were observed:  
  SLIME CONTROL EFFECTIVENESS The test procedure used was that explained in Example 1. For comparative purposes, two commercial TABLE 2 Weight Ratio Quantities Producing End Points (ppm) Q, of A to B Q. Qn Mixture QA/Qu QH/Qh Q&#34; Q1 The above evaluation established that the compositions in the weight ratios evaluated all exhibited synergistic activity. As set forth in the explanation of the test earlier in this text, when Q. /Q,, +Q is less than i. then the two individual components are acting in a synergistic manner.  
 BACTERICIDAL EFFECTIVENESS The bactericidal effectiveness of the combination of this Ex-ample was tested in accordance with the procedure outlined in Example 1. The values obtained are recorded in Table 2A which follows:  
 25 active in kill percentage.  
 TABLE 2A Quantity (ppm) required for inhibition Biocidal Material of A. aerogenex Compound A (5%). Compound B (5&#39;71). Inert (90%) 300 TABLE 2C Quantity of Percent kill Biocidal Material biocide (ppm) after 6 hours Compound A (5%). Compound B (57:). lnert (90%) 5 0 do. do. do. l0 l2 do. do. do. 25 35 do. do. do. 50 95 do. do. do. 100 I00 Pentachlorophenol (100%) 5 4| do. 10 59 do. 87 do. 50 100 do. I00 100 Commercial Product active See Table IC) 5 0 do. do. 10 0 do. do. 25 0 do. do. 18 do. do. l00 28 50 The above data established that the combination ef- EXAMPLE 3 fectively inhibited the growth of the particular bacterial Strain SYNERGISTIC COMBINATION Compound A: 5-chloro-4-phenyl-l,2-dithiole-3-one Compound B: 2-chloro-4-phenylphenol The combination of this Example 5-chloro-4-phenyl-l ,2-dithiole-3-one ferred to as Compound A) FUNGICIDAL EFFECTIVENESS The effectiveness of the composition of Example 2 was tested in accordance with the procedures set forth in Example 1. The results were:  
  contained (hereafter reand 2-chloro-4- Table 2B Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (S /r). Compound B (5% Inert (90%) 500 500 The composition was quite effective in controlling fungus growth when it is considered that it contained only 10 percent active material.  
 phenylphenol (referred to in this Example as Compound B). As with the previous Examples, combinations of these ingredients were tested in accordance 9 with the various test procedures outlined in Example 1. As with the previous Examples, the composition was The data obtained is recorded in the. follwing Tables compared with commercially available products using 3through 3C. samples of water derived from the sump of an air- Synergistic Index Test 3 washer of an industrial cooling water system located in For mixtures of Compounds-A and B, and for Com- 5 the northeastern United States. pound A and Compound B acting alone, the following Again, the slime control effectiveness of the instant results were observed: composition even at only 3 hour contact times was su- TABLE 3 Weight Ratio Quantities Producing End Points (ppm) Q Q Of A [O B Q; I I Q]: Mixture QA/Qu H h Q1: OI:  
 100/0 16.0 l 95/5 15.2 r 0.8 t 16.0 0.950 0.027 0.98 50/50 7.0 7.0 14.0 0.438 0.233 0.67 5/95 f 1.0 19.0 20.0 0.063 0.633 0.70  
  The results obtained for this particular combination perior to the commercial products at low treatment established unequivocally that the two ingredients beranges and was significantly better overall as compared have synergistically together. to the percent active Commercial Product.  
 BACTERICIDAL EFFECTIVENESS EXAMPLE 4 The test procedure as described in Example 1 was SYNERGISTIC COMBINATION utilized. The results established that the composition 2 Compound A: 5-chloro-4-phenyl-l,2-dithiole-3 one was effective in controlling this strain of bacteria. ompoun BI .6-t tr1Chl0r0phnOl TABLE 3A Quantity (ppm) required for inhibition Biocidal Material of A. aarugenes Compound (3%), Compound B (5%). lnert (90%) I 300 i FUNGICIDAL EFFECTIVENESS V l Synergistic Index Test The synergistic activity of the combinations of 5- chloro-4-phenyl-1,2-dithiole-3-one (referred to as Compound A) and 2,3,4,6-tetrachlorophenol (referred to in this Example as Compound B) was evaluated in The fungicidal activity of the composition of this Example was tested in accordance with the procedure previously described. The results were:  
 Compound A (5%), Compound B (5%). Inert (90%) g 500 500 SUME CO O EFFECTIVENESS accordance with the test described. The results were as follows:  
  The slime control effectiveness of the present com- For mixtures of Compounds A and B, and for Composition was evaluated using actual paper mill water as pound A and Compound B acting alone, the following explained under the procedure outlined in Example 1. results were observed:  
 TABLE 3C Quantity of Percent kill Biocidal Material biocide (ppm) after 3 hours Compound A (5%), Compound B (5%), Inert 5 5 do. do. do. 10 63 do. do. do. 25 76 do. do. do. 50 do. do. do. 100 100 Pentachlorophenol 100%) 5 4 do. 10 24 do. 25 71 do. 50 98 do. f 100 100 Commercial Product (30% active See Table 1C) 5 0 do. do. i 10 0 do. do. 7 25 5 do. do. 50 19 do. do. 100 23 TABLE 4 Weight Ratio Quantities Producing End Points (ppm) Q Q of A to B Q; Q Mixture Q /Q Q /Q, 0,,  
 Trial (1) I00/0 18.0  
  50/50 14.0 14.0 28.0 0.778 0.047 0.83 5/95 4.0 76.0 80.0 0.222 0.253 0.47 0/I00 300 Trial (2) 100/0 5.0  
 The Combinations exh b te a QA/Q QB/QB of from the airwasher sump of a cooling tower located in less than 1 which, of course, established that the indithe northeastern United States. vidual ingredients operated in concert to produce a The composition of this Example, as with the previsynergistic result. ous Examples, exhibited overall desriable and attractive slime control capacity. Of special interest is the BACTERICIDAL EFFECTIVENESS fact that at low percentage active concentrations the The efficacy of the compositions of this Example was compositions were capable of controlling the slimetested in accordance with the procedure outlined earforming organisms. lier. The results of the test clearly established that the combination of the instant invention is effective even EXAMPLE 5 at low percentages of active ingredients. SYNERGISTIC COMBINATION TABLE 4A Quantity (ppm) required for inhibition Biocidal Material of A. aerogenes Compound A (57:). Compound B (57:). Inert (90%) 300 FUNGICIDAL EFFECTIVENESS Compound A: 5-chloro-4-phenyl-l,2-dithioIe-3-one The fungicidal activity of the composition of this Ex- S pq B: 4 Chloro&#39;zcyclopemylphenol ample was tested in accordance with the procedure ilfi w Test. previously described. The result of this evaluation was e synerglstlc actmty of the combmauons of as follows: 5-chloro-4-phenyl-l.2-dithiole-3-one (referred to as TABLE 4B Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (5%), Compound B (5%), Inert (90%) I00 500 SLIME CONTROL EFFECTIVENESS Compound A) and 4-chloro-2-cyclopentylphenol (re- As in the previous Examples and in the manner set ferred to in this Example as Compound B) was evaluforth in the previous Examples. the slime control effecated in accordance with the test described. The results tiveness of the composition of Example was tested. The were as follows: outcome of this evaluation and the data derived using For mixtures of Compounds A and B, and for Comthe Commercial Products are set forth in the following pound A and Compound B acting alone, the following Table. The water sample used in this test was obtained results were observed:  
 TABLE 4C Quantity of Percent kill Biocidal Material biocide (ppm) after 6 hours Compound A (57:), Compound B (571), Inert 5 35 do. do. do. [0 45 do. do. do. 25 64 do. do. do. 50 85 do. do. do. I00 I00 Pentachlorophenol (I007!) 5 41 do. IO 59 do 25 87 do. 50 do. 100 I00 Commercial Product (30% active See Table IC) 5 0 do. do. 10 0 do. do. 25 0 do. do. 50 18 do. do. I00 28 TABLE 5 Weight Ratio Quantities Producing End Points (ppm) Q -l- 0,, Of A to B Q3 Mixture QJ/Qu Qn/Qli Q&#34; 0!;  
 All of. the combinations tested exhibited a QA/Qa cial interest is the fact that at low percentage active +QB/Qb of less than I which, of course, established concentrations the compositions were capable of conthat the individual ingredients operated in concert to trolling the slime-forming organisms.  
 produce a synergistic esult When the inventive compositions are employed in BACTERICIDAL EFFECTIVENESS IS the treatment of coollng or paper mill water, they are preferably utilized in the form of relatively dilute solu- The efficacy O he C PO U HS 0f thlS mp Was tions or dispersions. For example. a preferred solution tested in accordance with the procedure outline earlier. comprises b tw 5 percent to 65 percent by weight The results of the test clearly established that the comf h Synergistic bi i i admixture i h i.  
 bination of the instant invention is effective even at low Gus l nt d solubilizing agents. ,An example of Percentages of active ingredients such a synergistic biocidal product comprises from TABLE 5A Quantity (ppm) required for inhibition Biocidal Material of A. aerogenes Compound A (5%), Compound B (5%), lnert (90%) 300 FUNGlClDAL EFFECTIVENESS about 5 to percent by weight of the phenol, from about 5 to 10 percent by weight of the 5-chloro-4- The fungicidal activity of the composition of this Exphenyl-l,2- i hi0l -3-0n n he remainder compose ample was tested in accordance with the procedure of such materials as surfactants, stabilizers, organic solpreviously described. The result of this evaluation was vents. su h as al an s. ar mati hyd a ns and/ r as follows: water.  
 &#39; TABLE 5B Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (57:), Compound B (5%), lnert (907:) 500 500 SLI E CON EFFECTIVENESS surfactants such as the alkylaryl polyether alcohols, As in the previous Examples and in the manner set polyether alcohols, sulfonates and sulfates. and the forth in the previous Examples, the slime control effeclike may be employed to enhance the dlsperslblmy and tiveness of the Composition of the Example was-tested stability of these dispersions. The foregoing solutions of The outcome of this evaluation h the data derived the biocidalcompositions are utilized in order to insure using the commerical products are set forth in the folh fapld urflform dlspefslblhty of the blocldes lowing Table The water sample used in this test was wtthm the industrial water which 15 treated. It has been obtained o the Water tray of a paper machine of a found that either aqueous or non-aqueous solvents are mill located in the northeastern United States. generally Sultable the Preparatlon of composltlons of TABLE 5C Quantity of Percent kill Biocidal Material biocide (ppm) after 3 hours Compound A (571). Compound B (5% lnert 5 38 do. do. do. i0 84 do. do. do. 25 86 do. do. do. 50 92 do. do. do. 100 95 Pentachlorophenol 1007:) 5 89 (l0. l() 94 do. 25 do. 50 100 do. I00 100 Commercial Product (30% active See Table lC) 5 38 do. do. 10 36 do. do. 25 9 do. do. 50 0 do. do. 100 36 The composition of this Example exhibited overall the invention, e.g., methyl cellosolve, organic solvents,  
  desirable and attractive slime control capacity. Of spesuch as the aliphatic and aromatic hydrocarbons, e.g.,  
 kerosene. Based upon the synergism study as outlined above, it was ascertained that in the treatment of paper mill and cooling water, effecive biocidal actions is obtained when the concentration or treatment level of the combination or admixture of biocides is between 0.5 parts per million to 1,000 parts per million, and preferably between 1 and 100 parts per million, based upon the total content of the aqueous system treated, such as the total quantity of cooling water or paper mill water.  
  The compositions may also be utilized for the preservation of slurries and emulsions containing carbohydrates, proteins, fats, oils, etc.; dosage levels for this purpose range in the vicinity of 0.01 to 5 percent. The compositions of the invention which can be prepared by merely combining the respective ingredients and mixing thoroughly at standard conditions may be fed continuously &#39;to the treated system, e.g., by means of a metered pump, or may be fed periodically at predetermined intervals calculated to control the growth of slime-forming organisms in the system. Naturally, in the treatment of cooling water, the feeding of the inventive compositions must be designed to compensate for blowdown in those systems which employ that expedient.  
  Although the foregoing has been specifically directed to liquid formulations, the combinations of the invention may, of course, be formulated dry with well-known pelletizing agents, e.g, sodium chloride, talc, aluminate, etc. to produce solid pellets or briquettes which are added directly to the systems to be treated. The pellets or briquettes, of course, dissolve in accordance with predetermined conditions or rates.  
  In describing the inventive subject matter, the expression composition&#34; has been utilized. However, it is to be understood that physical compositions or combinations are not the sole utility of the invention. If, for example, the separate ingredients of the composition&#34; are added independently to a particular system, it is intended that this usage of the subject matter is within the scope of the invention and is to be construed within the broad interpretation of composition and/or combination.&#34;  
  As would be expected, the inventive composition may be added to the cooling water or paper and pulp mill systems at any convenient point. Naturally, in once-throughor non-circulating systems, the composition must be addedupstream from the point or points at which microorganism control is desired. In circulating systems or pulp and paper systems, the compositions must be added at any point provided that the time lapse and the conditons experienced between point of addition and the point at which the effect of the composition is to be experienced are not so drastic as to result in the neutralization of the effect of the composition.  
  Although the invention has been described specifically as being directed to specific compositions comprising 5-chloro-4-phenyl-1,2-dithiole-3-one in combination with the phenol as described in Example 1, the phenylpheno] of Example 2, the 2-chlorophenylphenol of Example 3, the chloropehnol of Example 4 or the pentylphenol of Example 5, it is obvious that homologues, analogues, etc. of the dithiole-3-one compound certainly are operable for the purpose. Likewise, the derivatives of the specially exemplifed organo-bromine compounds also have utility in the present inventive concept. Moreover, as earilier described, mixtures of the various organo-bromine compounds would also serve the purpose. the provision, of course, is that the organo-bromine compound possesses biocidal or growth inhibitory capacity with respect to bacteria, fungi, and algae.  
  It should be noted that while the evidence has been derived from the treatemnt .of samples taken from paper and pulp mill aqueous systems, the compositions and methods of the present invention are broadly applicable to the treatemnt of aesthetic waters as well as industrial waters such as cooling waters which are plagued by deposits formed by slime-forming organisms, or by the very presence such organisms.  
 Having thus described the invention, what we claim 1. A method for controlling the growth of the microorganism Aerobacter Aerogenes in an aqueous system in which said microorganism is found which comprises adding to said system so as to contact said microorganism an effective amount of a combination comprising 5-chloro-4-phenyl-l,2-dithiole-3-one and phenol, where the weight ratio of the dithiole to the phenol is from 5 percent to percent to 95 percent to 5 percent.  
  2. The method of claim 1 where said weight ratio is 50 percent to 50 percent.  
  3. The method of claim 1 where said combination is added to said system in an amount of from 0.5 to about 1,000 parts by weight of said combination per million parts by weight of said aqueous system.  
  4. A composition which is effective in controlling the growth of the microorganism Aerobacter Aerogenes in aqueous microorganism system where said is found which comprises 5 chloro-4phenyl-1,2-dithiole-3one phenol, wherein the weight ratio of the dithiole to the phenol is from about 5 percent to 95 percent to 95 percent to 5 percent.&#34;  
 5. The composition of claim 4 wherein said weight ratio is 50 percent to 50 percent.