PT100872A - Methods and systems of compositions for control of the growth of microbial agents in aqueous media based on chlorine and glycoluryl - Google Patents

Abstract

The present invention relates to methods and compositions for hygiene (cleansing) of aqueous media which combine a composition that is a chlorine source and a composition that is a glycoluryl source. The method is essentially characterized in that a total available chlorine concentration effective for control of the growth of microbial agents and a glycoluryl concentration varying between about 0.1 and about 40.0 ppm, effective for stabilizing the total available chlorine, are maintained in the water. The compositions are added together or separately, continuously or batchwise, and by any one of a series of methods. The glycoluryl compound stabilizes the chlorine and prolongs its useful life as a microbicidal agent.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to the field of disinfectant systems for pools and mineral water, cooling tower water, and other aqueous media. More particularly, the invention relates to systems which use chlorine as a disinfectant, and to compositions and methods for stabilizing and increasing the chlorine lifetime in such systems.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The continuous increase in the number of pools in use each year has led to the need to find a more effective, safe and convenient chemical disinfection. Chlorine in various forms is the most widely used chemical for this purpose, as it is both economical and highly effective in controlling bacteria and algae. However its effectiveness varies, and depends on the method used to introduce the element into pool water and the type of chlorine compound used. Chlorine gas, hypochlorites, and chlorinated organic agents are all used for the disinfection of swimming pools and present different types of chlorine residues and varying degrees of bactericidal activity, algicidal activity, and chemical consumption. In addition, external variables such as pool usage and climatic conditions have significant effects on the effectiveness of the disinfection action.

Several methods for stabilizing chlorine in disinfection systems have been proposed in the techniques. For example, in U.S. Patent No. 2,988,471, issued to Robert J. Fuchs et al. on June 13, 1961, there is described a method for 3-

stabilize the chlorine in aqueous solutions against decomposition by exposure to ultraviolet light or by contact with iron and copper. The method involves the addition to the aqueous solution of cyanuric acid, amelide or a salt thereof. The loss of active chlorine is said to be substantially reduced when the weight concentration of the cyanuric acid is higher than the concentration by weight of the available chlorine. The use of cyanuric acid to substantially reduce the loss of active chlorine in aqueous systems exposed to sunlight, for example in swimming pools, has been commercially widely accepted. See also, for example, U.S. Patent No. 4,187,293, published by Nelson on February 5, 1980.

Although satisfactory results are achieved with the use of cyanuric acid, there are serious problems. One problem is the relatively short half-life of active chlorine when exposed to sunlight. At 50 ppm of cyanuric acid, the half-life of chlorine is only seven hours. On a normal sunny day most of the chlorine disinfectant is rapidly depleted.

A second problem that exists is the formation of cyanuric acid in the aqueous systems. It is recommended that atypically high concentrations of cyanuric acid be reduced to less than 10 ppm by partially draining pool water by refilling with fresh water. Indeed, in commercial pool operations some health officials will close a swimming pool if cyanuric acid exceeds 70 ppm. Kirk-othmer Encyclopedia of Chemical Technology, 3rd Ed. Vol. 24, p. 430.

In contrast to the present invention, halogenated glycolurils have been proposed in the prior art as the chlorine source of disinfection. For example, in U.S. Patent No. 3,165,521, issued to Slezak et al. on January 12, 1965, a method for disinfecting the water systems 4

aqueous solutions in which haloglycolurils are used as the source of free chlorine to function as pool disinfectants. The amount of the compound used is that which provides satisfactory disinfection levels of residual chlorine, i.e., about 0.4 to 0.8 ppm. The use of haloglycolurils as the disinfectant in pools is also disclosed in U.S. Patent No. 3,165,521, issued by Lezak. The use of polyhaloglycolurils for the control of algae in water is shown in U.S. Patent No. 3,252,901, issued to Zettler. The use of chlorinated glycolurils in the treatment of sewage is disclosed in U.S. Patent No. 3,445,383, published by Horvath et al. The glycoluril preparation is shown in U.S. Patent No. 2,731,472, issued to Reibnitz. U.S. Patent No. 3,071,591, issued to Paterson, discloses a method for the preparation of N-halogenated glycolurils containing both bromine and chlorine for use as disinfecting agents. Various other disinfection techniques have involved the use of certain substituted glycoluryls. The use of

I substituted glycolurils in combination with trichlorocyanuric acid and sodium stearate in " sticks " of disinfection is disclosed in U.S. Patent No. 3,342,674, issued by Kowalski. The use of chlorinated glycolurils in combination with a metal hypochlorite in the treatment of sewage is disclosed in U.S. Patent No. 3,629,408, issued to Horvath. U.S. Patent No. 3,187,004, issued to Slezak, discloses the synthesis of alkyl and aryl substituted glycolurils and their use in pool disinfection. This patent discloses the use of halogenated glycolurils in N with alkali metal salt. 5

While these various techniques for disinfecting pools, etc., have been proposed in the prior art, there remains a substantial need to find improved compositions and methods that provide for prolonged disinfection of the aqueous media. Although many in the past have sought to obtain chlorine based systems, the shelf life in these systems has remained undesirably short. Viable commercial proposals were not published, and theoretical proposals were dropped. The present invention satisfies the need for an effective, stable, chlorine-based disinfection system.

SUMMARY OF THE INVENTION

It is an aspect of the present invention that glycoluril has been found to stabilize the added chlorine for disinfection of an aqueous medium, thereby prolonging the shelf life of the added chlorine compounds. The glycoluril may be added at any time, either before or after the addition of the chlorine source composition, and is maintained at the level determined to provide a desired stabilizing effect for the chlorine.

Aqueous systems, such as pool water, operated with treatment programs based on this presentation allow efficient use of chlorine disinfectant by substantially increasing the half-life of chlorine. Several advantages are thus obtained. Cost savings will be made because pool water will consume up to 50% less chlorine in a normal pool season. In addition, reducing the amount of chlorine consumed will reduce the formation of certain chemicals, such as cyanuric acid, associated with the use of particular chlorine source compositions, for example trichloro-s-triazinetrione (TCCA). 6

Controlling the source composition of chlorine and glycoluril at the rates indicated in this presentation enables the actuation of a very effective treatment program for aqueous systems.

Other objects of the present invention include providing compositions and methods for reducing the presence of trihalomethanes and unpleasant odors associated with certain chlorine source compositions such as TCCA.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to promote an understanding of the principles of the invention, reference will now be made to the preferred embodiment of the invention and specific language will be used to describe it. It should be understood, however, that no limitation of the scope of the invention is intended, the changes, modifications and other applications of the principles of the invention being contemplated as would be by any person skilled in the art with which the invention relates. The use of chlorine as a disinfectant for pool water, cooling tower water and other aqueous media has been well known for many years. In these media, chlorine compounds are added continuously or periodically to the water to maintain a microbicidal concentration of chlorine. Without periodic addition, the effective chlorine concentration in the water will decrease due to dissipation, reaction, conversion into unusual forms, etc. According to prior methods, the added chlorine lifetime has been undesirably short, and an unmet need remained to extend the effective lifetime of the added chlorine compounds. 7

The present invention provides compositions, systems and methods for prolonging the shelf life of chlorine provided to the aqueous media for purposes of disinfection. In particular, the present invention utilizes glycoluril activity as a stabilizer for chlorine in an aqueous medium. The addition of glycoluril and chlorine compositions may be done at the same time or at different times, in a continuous or periodic manner, and by any of a number of addition methods. The presence of the glycoluril at a stabilization concentration appropriate for the chlorine concentration will result in a prolonged effective lifetime for the chlorine at a stage suitable for microbicidal activity. For example, the half-life for trichloro-s-triazine trione (TCCA) in a given system is about 6-7 hours, while the use of glycoluril in the system prolongs the half-life to about 25 hours. The present invention utilizes a glycoluril source composition which provides glycoluril in order to stabilize and extend the chlorine shelf life. The glycoluril source compositions useful with the present invention include any one that contributes a glycoluril compound compatible with and useful for stabilizing chlorine, and is suitable for the aqueous medium to be treated. Substitution of the glycoluril is not of critical importance as long as the substituents do not interfere with the utility of the glycoluril in the manner described herein.

As used herein, the term " glycoluril " encompasses a compound comprising the basic formula:

m -CH (NH 2) o - (CH 2) c - o (I)

I I o I

NH-CH-NH wherein a is 0 or 1. In addition to the unsubstituted glycoluril (I), glycoluril source compositions include the chloro, alkyl and phenyl substituted glycoluryls. The term glycoluril thus includes compounds having the above basic structure (I), as well as compounds including substituents such as alkyl, phenyl and chloro groups at available binding sites. Bromo-substituted glycolurils may also be useful in certain applications, although the presence of the bromo substituent may interfere in some systems with the utility of glycoluril as a chlorine stabilizer.

More specifically, preferred glycoluril source compositions include glycolurils having the following structure:

N - (X)

0 * C

I (X) -N-

I c- (ÇU2) ç

I to I

(X) â € ƒâ € ƒâ € ƒwherein R6 are independently selected from the group consisting of hydrogen, lower alkyl radicals having 1 to 4 carbon atoms, and phenyl; each X is hydrogen, chlorine or bromine; and a is either 0 or 1. It is preferred that R and R1 are either hydrogen or methyl, since alkyl radicals with greater carbon lengths render the glycolurils less soluble in water. The concentration of chlorine in the aqueous medium may be obtained from any suitable source which provides hypochlorous acid (HCl) to the water. Compositions chlorine sources may include both inorganic and organic materials. Useful inorganic materials include molecular chlorine, lithium hypochlorite (LiOCl), calcium hypochlorite (Ca (OCl) 2, sodium hypochlorite (NaOCl) and hypochlorous acid (CHCl)) Organic sources may include, for example, bromochlorodimethylhydantoin (BCDMH), dichlorodimethylhydantoin (DCDMH) or compositions based on cyanuric acid such as dichloro-s-triazinotrione or sodium or potassium trichloroisetrione (TCCA) These compounds are readily available in commercial form. from a number of different suppliers including Monsanto Chemical Co. under the name ACL-90. The preferred composition is TCCA, however, it will be appreciated that the source of chlorine is not of critical importance to the present invention, provided that the source is compatible with the aqueous system to be treated and is stabilized by the glycoluril compound that is used.

A wide range of aqueous media can be treated by the present invention. In general, any aqueous medium which is effectively treated with chlorine, and which is compatible with the chemicals described, may be treated. Typical systems for which the present invention is useful include pools, mineral waters, hot baths and related therapeutical baths, decorative fountains, recrystallization water cooling systems, dehumidification systems, reservoirs and purge water systems.

The concentrations of glycoluril and chlorine will vary depending on the aqueous medium to be treated. An advantage of the present invention is that the glycoluril level can be rapidly harmonized with the desired chlorine concentration effective for a given aqueous system. The glycoluril level will facilitate the maintenance of the desired microbicidal level of the chlorine in the water.

Appropriate concentrations of chlorine, and thus glycoluril, will also differ based on the conditions present in the aqueous media. For example, effective levels may differ depending on such factors as the extent and nature of the microbicidal activity needed, the presence of other chemical treatments, and conditions of use such as temperature, amount of sunlight, pH, etc. Generally, any factors that affect chlorine stability will have an impact on the desired levels of glycoluril. The present invention contemplates that the desired level of chlorine and glycoluril may be

be readily determined by one skilled in the art without undue experimentation, and concentrations. specific are therefore not specified herein for each of the varieties of treatable aqueous systems. The level of glycoluril in water is that which provides an effective concentration of glycoluril in order to usefully stabilize the chlorine present in the system. Typical glycoluril concentrations effective as described will range from about 0.1 to about 40.0 ppm glycoluril in water. More preferably, the glycoluril is present in the water at about 1.0 to about 10.0 ppm, most preferred being 3.0-7.0 ppm for many applications.

In some instances, it may be desirable to provide glycoluril levels as high as 100 ppm, such as in the initial treatment of a pool. In this way, the glycoluril level would remain at an effective level for an extended period of time. Such elevated glycoluril levels may also be used in combination with particularly high levels of chlorine in the water. The concentration of chlorine in the water is that which provides an effective level of chlorine for the degree of microbicidal activity desired for a given aqueous medium. The term "total available chlorine" is used herein to include both free chlorine and combined chlorine. Typically, a suitable concentration of total available chlorine will be in excess of about 1.0 ppm and will preferably range from about 1.0 to about 5.0 ppm in water. This is true, for example, in the case of pool water. By comparison, the total available chlorine level in the cooling tower may differ, ranging from about 1.0 to about 10.0 ppm of the total available chlorine. 12

The present invention advantageously uses two separate compositions, one primarily providing the chlorine and the other mainly providing the glycoluril. The overall effect is that glycoluril is maintained at a level that stabilizes chlorine and extends its lifetime to reduce the amount and frequency of chlorine addition. While certain forms of glycoluril source compositions may include chlorine that will be delivered to water, such glycoluril forms are contemplated in the present invention as primarily stabilizing compositions. Indeed, the amount of chlorine that may be added to the water via a chlorinated form of glycoluril is typically or insufficient, or will require the use of amounts of chlorinated glycoluril which are otherwise undesirable.

The glycoluril and chlorine compositions may be administered to the aqueous medium in any manner effective to provide the desired concentrations of each compound. The glycoluril and chlorine may be added to the water either together or separately, and either periodically or continuously. The methods of application may vary according to the aqueous systems to be treated, and the conditions of use which are pertinent to it. In general, however, the methods are restricted only by the need to maintain effective levels of glycoluril and chlorine as described, and may be any suitable methods for the particular physical forms and compounds used. Existing chlorine disinfecting systems contemplate various methods for maintaining a desired level of chlorine in an aqueous system. The present invention is advantageous in that it can be readily adapted for use with a wide range of such existing water treatment systems. 13

Typical methods of addition known in the art are methods of emission and erosion. Emission refers to a direct addition of the chemical to the aqueous medium in a solid, typically granular, or liquid form. Compositions useful in the present invention may be rapidly prepared in forms and concentrations convenient for emission application.

In the erosion method, the compositions are made of a solid material which is contacted with water in a manner which causes a relatively slow erosion of the solid material, thereby gradually releasing the composition into the water. The composition to be added is formed or pressed into solid forms, such as tablets, "sticks", disks and other formats, typically by a hydraulic or mechanical press. The materials in solid form may include inert fillers, such as sodium chloride or boric acid, which aid in the compression process. The solid material may also contain other ingredients such as compression aids, for example, mold releasing agents, binding agents, corrosion inhibitors, desquamation inhibitors and other components known to those skilled in the art. Erosion methods are commonly used in the prior art to introduce chlorine source compositions into pools, for example. The chlorine composition in solid form is placed in a release device through which water is circulated in order to erode the solid material. In the case of a pool, the tablet, " stick " or disk may be placed in a skimmer basket, in-line or off-line delivery agents, or in a floating release device. Although erosion may also be used for glycoluril, it has been found that at least certain forms and types of glycoluril are not well suited for introduction by continuous erosion methods, 14 because for these forms erosion provides insufficient levels of glycoluril in water .

Source glycoluril and chlorine source compositions may be provided either as two separate materials or as a physically combined product, depending on the form and intended mode of addition of the products. The provision of separate materials is preferred since the preparation of the compositions is thereby rendered simpler. It also happens that methods and compounds for adding chlorine and glycoluril are more flexible, for example by allowing the use of liquid chlorine with a granular glycoluril composition, or permitting the continuous addition of the chlorine by erosion and a periodic emission of the glycoluril composition . The separate addition further allows the user to independently control the concentrations of the two compounds, which will be particularly useful if the water conditions result in a disparate depletion of one compound compared to the other.

A particular method for maintaining the desired levels of chlorine and glycoluril is to provide a continuous addition of chlorine to the water, along with a periodic emission addition of the glycoluril compound. The additive glycoluril source compositions may be formulated rapidly to provide the desired levels of glycoluril in the water upon addition of prescribed amounts of material with indicated time intervals. For example, granular forms of the compositions may be prepared rapidly which provides for desired concentrations of glycoluril when added to the water at intervals ranging from daily or once every one to two weeks. Of course, the frequency of the addition will depend on the conditions to which the water is subjected, and also on the amount,

concentration and type of glycoluril source composition to be added.

In a particular embodiment, the above method may be improved by using as the chlorine source a mixture of a chloro compound and a glycoluril compound in a physical combination that facilitates a constant release of the chloro compound into the water. Thus, a tablet form or " stick " of chlorine source material can be formulated so that it also includes a percentage of glycoluril. The glycoluril is formulated with the chlorine source compound in the tablet or " stick " solid because it was found that this would retard the erosion rate for the solid material. This in turn extends the life of the solid material and reduces the frequency with which the tablets or "sticks" need to be replaced. Accordingly, the chlorine is added to the aqueous system at a controlled and uniform rate over a longer period of time. The tablet in this method will also contribute to a certain amount of glycoluril in the water, but the desired level of glycoluril may not be primarily obtained from this source. Instead, a glycoluril source compound is also otherwise added, such as by periodic emission, to raise and maintain the glycoluril level in water as desired.

According to this particular technique, the tablets or " sticks " in solid form are formulated so as to include both chlorine source compounds and glycoluryl source. The chloro compound is preferably selected from the group consisting of calcium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinotrione, potassium dichloro-s-triazinotrione and trichloro-s-triazinetrione, and is present in an amount which ranges from about 50.0% to about 99.99% by weight. The glycoluril source composition is preferably 16

selected from the group consisting of glycoluril, alkyl substituted glycoluril, phenyl substituted glycoluril, chloro substituted glycoluril, and is present in an amount ranging from about 0.01% to about 50.0% by weight. Another discussion of such compositions and their advantages is contained in co-pending U.S. Patent Application Serial No. 652,983, filed February 11, 1991, and incorporated by reference herein.

According to this method, an execution of the chlorine material in solid form comprises about 50-99.99% by weight of trichloro-s-triazinotrione and 0.01-50% by weight of glycoluril. In a related embodiment, the solid form material comprises about 50-99.9% by weight trichloro-s-triazinetrione, 0.01-50% by weight glycoluril and 0-20% by weight of an alkali bromide salt. A preferred composition is 80-98 & trichloro-s-triazinotrione (TCCA) and 2-20% glycoluril, or 70-90% trichloro-s-triazinotrione (TCCA), 5-10% sodium or potassium bromide salt, and 5-20% % glycoluril. Another preferred blend is 75-90% trichloro-s-triazinetrione, 5-10% potassium bromide and 5-20% glycoluril. Preferred glycolurils are unsubstituted glycoluril (1) and chloroglycolurils, such as dichloro glycoluril and tetrachloroglycoluril. For most applications glycoluril is preferred. By way of particular example, the present invention is well-suited for use in the treatment of pool water, current systems provide the addition of chlorine in order to maintain certain acceptable levels, typically 1 to 5 ppm of total available chlorine in the water. The present invention may be directly adapted for use in the series of prior art systems which use chlorine as a disinfectant by maintaining in those systems the indicated levels of glycoluril effective for 17

stabilize the chlorine. Glycoluril can also be used with various other chemical treatments typically used in such systems, such as algicides, clarifiers, etc.

In addition, it is a feature of the present invention that the compositions can be readily formulated to suit their use in pools and other aqueous systems. Pool chemicals, for example, are typically formed to require the addition of convenient, prescribed amounts on a periodic basis, usually weekly. The chemicals used in the present invention may be formulated in this base. More preferably, the present invention extends the shelf life of chlorine to such an extent that the frequency of the addition of chemicals can be extended beyond the usual weekly basis, perhaps to once every two weeks or to a longer period .

In a typical pool application, the present invention would proceed as follows. More or less every week the user employs a prescribed amount of tablets or " sticks " source of chlorine in the solid form in an erosion device. In addition there is the periodic addition of the glycoluril source composition, also preferably at one week intervals. The presence of glycoluril prolongs the shelf life of chlorine by reducing the frequency at which chlorine would otherwise be added.

In an alternative method, the solid form material includes the chlorine and glycoluril source composition, for example about 95% TCCA and about 5% glycoluril. This formulation has a slower erosion rate compared to the prior art chlorine products, and thus will last up to two weeks or more. The stabilization of chlorine by

glycoluril binds well with the prolonged erosion time of these tablets or " sticks " alternatives.

In addition, other chemicals may be used at the same time. In particular, it may be desirable to perform " shocking " pool water or other water, a common step in prior art processes. In this case, the shock can conveniently be carried out, for example every two weeks, by adding conventional material, such as sodium dichlorocyanurate, at the same time as adding the glycoluril. A complete pool treatment system would only require the addition of algicide, such as a quaternary ammonium compound, over the same period of two weeks, thereby providing the user with a system and method suitable for the treatment of pool water.

It has been observed that the ratio of glycoluril to total available chlorine can be selected in order to optimize the duration and microbicidal effectiveness of chlorine. The amount of glycoluril in the water is preferably limited to an appropriate degree to result in sufficient hydrolysis of the chlorine. It is possible that the presence of excess glycoluril in comparison with the amount of total available chlorine will affect the amount of chlorine in solution, and thus the microbicidal activity. In one sense, glycoluril may be present in amounts so high relative to chlorine that chlorine is rendered so stable as to reduce its microbicidal activity. For example, a standard hypochlorite solution will effectively kill 10 bacteria in about 30 seconds. A ratio of glycoluril to total available chlorine of about 5: 1 will result in the killing of about half of the bacteria in about two minutes, and higher ratios will further delay the time required for bacteria to die. Thus, although water systems having 19

higher glycoluril and total available chlorine levels still have microbicidal efficacy, performance will be decreased. Preferred ratios of total available chlorine to glycoluril have been found to range from about 10: 1 to about 1:10, more preferably from about 5: 1 to about 1: 5. While increased chlorine stability is usually associated with decreased microbicidal activity, the present invention provides increased stability and desired microbicidal activity. The present invention is useful in a wide range of applications. One skilled in the art can readily determine the covenience of a particular chlorine source composition and a source glycoluril composition for a given aqueous system. The present invention may also be used in conjunction with a number of other chemicals such as algicides, fungicides, clarifiers, pH adjusters, sequestrants, etc., and may be used with other chlorine stabilizers such as cyanuric acid, oxazolidinone, imidazolidinone , dimethylhydantoin, succinimide, toluenesulfonamide, sulfonamidobenzoic acid, melamine, dioxohexahydrotriazine, piperazinedione, and azodicarbonamidine.

In addition to chlorine stabilization, it has been found that the present invention also provides various auxiliary benefits to aqueous systems. For example, addition of glycoluril in the indicated amounts reduces the unpleasant odor of chloramine associated with certain chlorination systems, such as those using TCCA. Similarly, the development of trihalomethanes is decreased in the presence of glycoluril.

The following examples further illustrate the present invention, and are provided as exemplary but not restrictive of the scope of the present invention. 20

EXAMPLE 1

This example illustrates a method for the treatment of water systems according to the present invention. This experiment was conducted to demonstrate the rate of loss of chlorine from solutions containing cyanuric acid, glycoluril and mixtures of the two. This experiment was conducted under controlled conditions to simulate expected conditions when operating a pool under intense sunlight.

Four liter liters containing 3,500 mis of distilled water were placed in a Revco environment chamber equipped with a special ultraviolet lamp emitting UV radiation at 295-340 nm. It is known that chlorine is degraded by sunlight in the region of 295-340 nm. The water was balanced to the following specifications:

Calcium Hardness 200-250 ppm

Total Alkalinity 100-135 ppm pH 7.2-7.4

The test chemicals were then added as indicated in Table I below:

TABLE I

Test Systems Test Kit # 1 Cyanuric Acid (CYA) Glycolyl (PPM) 1 10 0 2 50 0 3 0 5 4 0 10 5 0 20 6 50 5 7 10 10 8 50 10 9 10 20 10 50 20 11 The need for chlorine in the test systems was satisfied by adding excess chlorine and leaving the water circulating at night.The total available chlorine level was adjusted the following morning with the TCCA stock solution The study was conducted over a 24 hour period, during which the test tubes were continuously shaken.The test solutions were exposed to ultraviolet radiation at 295-340 NM. air and water were monitored at 80 ° -85 ° F and relative humidity at 80-100% .Water samples were collected and the total available chlorine was measured using a HACH 3000 spectrophotometer and DPD colorimetric method.

large number of specimens involved, the study was conducted twice. per \

TABLE II

Test Data - Experiment # 1 Test # 1 2 3 4 5 CYA / G (ppm) 10/0 50/0 0/5 0/10 0/20 Time TC12 TC12 Td2 TC12 TC12 Initial 1.80 1.78 1.79 1.82 1.80 1 hr 1.36 1.48 1.65 1.68 1.67 2 hr 1.08 1.25 1.54 1.56 1.53 3 hr 0.93 1.15 - - - 9 hr 0.25 0.68 1.26 1.31 1.31 19 hr 0.09 0.27 0.95 1.01 1.01 24 hr 0.06 0.15 0.80 0.87 0 , 89

TABLE III

Test Data - Experiment # 2 POVETA # G 7 8 9 10 11 CYA / G (ppm) 0/5 10/5 50/10 10/10 50/20 10/20 Time TC12 TC12 tci2 tci2 TC12 TC12 Initial 1,50 1 , 51 1.52 1.53 1.60 1.5 2 hr 1.27 1.38 1.36 1.43 1.45 1.4 5 hr 1.15 1.24 1.29 1.31 1, 34 1.3 21 hr 0.89 0.82 0.94 0.98 0.98 0.9 24 hr 0.61 0.80 0.88 0.91 0.90 0.9 The purpose of this study was to to determine loss of total available chlorine (TC12) from the aqueous systems containing cyanuric acid, glycoluril and mixtures of the two when exposed to ultraviolet light in the wavelength region of 295-340 nm. The chlorine half-life was determined by recording the% of the total available chlorine (TC12) vs. time (hours). As indicated in TABLE IV, aqueous systems containing both cyanuric acid and glycoluril had a longer half-life than aqueous systems containing only cyanuric acid, i.e. the residual total available chlorine is dissipated more slowly in aqueous systems containing a combination cyanuric acid and glycoluril. Thus, chlorine is available for a longer period of time, and its bactericidal and disinfecting activity is more continuously effective.

TABLE IV

Chlorine Semi-Life CYA Glicoluryl Test # 1 íasal t 1/2 Ihr 1 10 0 5.0 2 50 0 7.0 3 0 5 22.0 4 0 10 24.0 5 0 20 25.0 6 50 5 29 , 0 7 10 5 27.0 8 50 10 33.0 9 10 10 35.0 10 50 20 32.0 11 10 20 35.0 EXAMPLE 2

Solutions comprising 1 ppm, 2.5 ppm and 5 ppm of total available chlorine from TCCA, and concentrations of glycoluril of 5, 10 and 25 ppm were tested for biocidal activity. These compositions were added to [test microbes] and the [death rate] was measured. As indicated in FIG. 1, each of the chlorine concentrations had higher biocidal activity at lower glycoluril concentrations. Additionally, the rate of biocidal activity in the 25 ppm glycoluril solution was slower than rates at 5 and 10 ppm glycoluril. EXAMPLE 3

This example examines the potential of glycoluril to fill through normal pool use. A pool on the 20,000-gallon vinyl floor was filled with water and balanced to the following specifications:

Calcium Hardness: 175 ppm

Total Alkalinity: 125 ppm pH: 7.4 CYA: 35 ppm The pool was maintained at 1 to 3 ppm total available chlorine using " sticks " of half-pound TCCA, tablets, and was subjected to shock treatment twice weekly using lithium hypochlorite to bring the total available chlorine level to 8 ppm.

During the eight-month test period the glycoluril level ranged from 1 to 5 ppm. A total of 1,125 grams of glycoluril was added to the pool during the test period. At the end of the test period less than 1 ppm of glycoluril was measured in water. EXAMPLE 4

This Example illustrates the ability of glycoluril to reduce the volatility of chlorine and inorganic chloramines from aqueous systems, thereby reducing the unpleasant odors caused by the compounds. The results indicate that glycoluril appears to effectively retard the loss of free chlorine and inorganic chloramines from aqueous systems. 27

In order to determine the effect of glycoluril on the volatility of chlorine and chloramines, the air withdrawal apparatus shown in Fig. 2.0 was constructed by initially passing through a glass wool bush in order to fix solid particles, like droplets of oil. The air was then passed through a column filled with activated carbon to subsequently clean the stream of air. After the carbon filter, another glass wool bushing fixed any carbon particles that might have escaped the spine. As shown above a sequential filtration like this generates required halogen free air. The required free air was channeled into a spray tank filled with required free water. The air leaving the tank must have been saturated with water. This water-rich air was used to eliminate chlorine from the solutions used in subsequent experiments. It was necessary to use air saturated with water for these experiments in order to minimize evaporative losses in the flasks containing the halogen solutions. In addition, to increase the effect of the air scavenging action, magnetic stirrers were used to continuously agitate the solutions. The chlorine was dosed into Erlenmeyer flasks containing one liter of required free water (resistance 18 megohm) at a concentration of 2 ppm. The concentration of ammonium chloride was 2 ppm. The glycoluril was added to give a final concentration of 1.2 or 5 ppm. Vial 1 contained chlorine and 5 ppm glycoluril, vial 2 contained chlorine and ammonium salt, vial 3 contained chlorine, ammonium salt and 1,2 glycoluril, and vial 4 contained chlorine, ammonium salt and 5 ppm glycoluril. In flasks 3 and 4, the ammonium chloride was added after addition of the chloro and glycoluril. The results are set forth in Table V and Figure 3. 28 OUADRO V Time = 0 Total Halo Oxygen Bottle 1 2.01 2 1.96 3 2.00 4 1.99 Time = 15 hr Halocrene Bottle Total ppm 1 1.96 2 1.16 3 1.10 4 1.46 Time = 19 hr Halooen bottle Total ppm 1 1.90 2 1.03 3 0.98 4 1.43 By adding glycoluril to Vial 1 the chlorine volatility decreased. Referring to Fig. 4, the entire line indicates the first 6 hours of data extrapolated at 21 ° hour. This is close to the rate of volatilization of chlorine under conditions 29

experiments. The dotted line demonstrates the effect of the glycolyl ether. The glycoluril was added at the sixth hour and the chloro release essentially ceased. EXAMPLE 5

Aqueous solutions containing 2.5 ppm total available chlorine and 5, 10 and 25 ppm glycoluril were prepared and tested over a 5 minute period for microbicidal activity according to the method of Example 2. The results of this test are reported in FIG. 5, indicating that the rate of biocidal activity in the 25 ppm glycoluril solution is slower than the 5 and 10 ppm rate of glycoluril. EXAMPLE 6

Another study was conducted to demonstrate the efficacy of chlorine as a disinfectant when stabilized with glycoluril and another chlorine stabilizer. As indicated in Fig. 6, a solution containing 1.5 mg / l of available total chlorine remains essentially equally effective as a disinfectant, either combined with 7 mg / l glycoluril alone or 7 mg / l glycoluril and 50 mg / 1 isocyanuric acid (CYA). The glycoluril used in accordance with the present invention in various concentrations as discussed above is an effective stabilizer for chlorine disinfectant and chlorine remains an effective disinfectant both in the presence and absence of other chlorine stabilizers. EXAMPLE 7 The following example illustrates the efficacy of

glycoluril to inhibit the formation of trihalomethanes (THM) from humic acid. Test solutions were prepared in new 120 ml vaccine bottles which were washed with chromic acid cleansing solution, rinsed with hot running water, and then distilled water before use. The following stock solutions were prepared for use in these tests: a solution of 20 ppm available commercial bleach chlorine, a 0.1% humic acid solution (humic acid, sodium salt; Aldrich Chemical Co., Inc. , CAS # 1415-93-6), a solution of 0.04% glycoluril, and a 0.1% solution of s-triazinetrione (CYA). Thirteen solutions were prepared as shown in Table VI. 31

TABLE VI

Preoaracão of Test Solutions ml of Test Stock Solution HA Bottle Como.G CYA Chlorine 1 0.3 1.5 - 6 2 0.3 3.0 - 6 3 0.3 7.5 - 6 4 0.3 15.0 - 6 5 0.3 1.5 6 6 6 0.3 3.0 6 6 7 0.3 7.5 6 6 8 0.3 15.0 6 6 9 0.3 - - 6 10 0 , 3 - 6 6 11 - 15.0 - 6 12 - - 6 6 13 - - 6

Each bottle was filled to 3/4 with distilled water in a boiled glass vessel, and the stock solutions were then added. Each bottle was then filled to the top with boiled distilled water, covered with a Teflon cap, and sealed with a shrouded metal vaccine cap. The bottles were kept at room temperature overnight and the next day were analyzed for the presence of trihalomethanes. The solutions were analyzed for chloroform, bromoform, bromodichloromethane and dibromochloromethane, and the results are shown in Tables VII and VIII. 32

TABLE VII

Concentrations of Reagents in Solutions and

Result Chloroform ppm ppm in each Solution ml of Solution Stock Test Results Bottle HA Comp.G CYA Chlorine (ppm CHC13) 1 15 5 - 10 0.015 2 15 10 - 10 <0.010 3 15 25 - 10 0.061 4 15 50 - 10 0.102 5 15 5 50 10 0.069 6 15 10 50 10 0.047 7 15 25 50 10 0.030 8 15 50 50 10 0.031 9 15 - - 10 0.137 10 15 - 50 10 0.081 11 - 15 - 10 0.088 12 - - 50 10 0.059 13 - - &lt; 0.010 9 33

TABLE VIII

Percent Reduction of Chloroform in Sample Compared to Control Solution 9, at 137 oob Bottle oob CHC1_% Reduction in THM 1 15 HA, 5G 3 15 89.1 2 15HA, 10G &lt; 3.0 &gt; 92.7 3 15 HA , 25G 61 55.5 4 15HA, 50G 102 25.5 5 15HA, 5G, 50CYA 69 49.6 6 15HA, 10G, 50CYA 47 65.7 7 15HA, 25G, 50CYA 30 78.1 8 15HA, 50G, 40CYA 31 77.4 9 positive control 137 - 10 15HA, 50 CYA 81 40.9 11 50 G 88 35.8 12 50 CYA 59 56.9 13 negative control &lt; 10 &gt; 92.7

As the data show, except for chloroform, the THMs were below the minimum detection level of less than 0.010 ppm in all test solutions. Solution 13 was a negative control, containing only 10 ppm chlorine in boiled distilled water, and had less than 0.010 ppm chloroform. When only CYA (# 12), only glycoluril (# 11) and CYA plus glycoluril together (# 10) were added to the chlorine solution, there were increases in chloroform to 59, 88 and 81 parts per billion (ppb), respectively. This indicated that the available chlorine reacted with these compounds or impurities in these compounds to form some chloroform. The addition of humic acid alone to the solution of 34

chloro (# 9) gave the highest chloroform value of 137 ppb, and acted as the positive control.

Solutions 1-4 represented varying concentrations of glycoluril in combination with 15 ppm of humic acid and chlorine. The results indicate that 5 and 10 ppm of glycoluril almost completely prevented chloroform formation, whereas 25 ppm only inhibited formation in 55.5%, and 50 ppm glycoluril only resulted in a 25.5% reduction over control positive. It is thus shown that low levels of glycoluril (5 and 10 ppm) prevent the formation of chloroform from humic acid almost completely, while higher concentrations inhibit the formation of THM but to a lesser extent. These results can be explained by the supposition that an impurity in the glycoluril would result in the formation of chloroform. At levels of 5 and 10 ppm, the impurity was too low to form an appreciable amount of chloroform, while at higher concentrations there were sufficient impurities to appreciably affect the test. In any event, the tests demonstrate the efficacy of the glycoluril to prevent or inhibit the formation of THMs.

Solutions 5-8 represent various levels of glycoluril with 50 ppm CYA. This treatment group gave a good reduction over the positive control, and the results were consistent with various concentrations of glycoluril. There was slight inhibition of chloroform at 5 ppm of glycoluril and greater inhibition at 10, 25 and 50 ppm of glycoluril in combination with CYA. Maximum inhibition was achieved at 25 ppm, with no improvement at 50 ppm. Thus, the optimum glycoluril range is between 10-25 ppm.

This test broadly demonstrates a defined reduction of chloroform from the reaction of chlorine with humic acid when τ 35 ο the treatment group contained both CYA and glycoluril. There was about 41% reduction by 50 ppm of CYA alone, but a reduction as high as 78% was observed with combinations of CYA and glycoluril. The combination of CYA and glycoluril was more effective at low concentrations than any compound alone.

Lisbon, September 17, 1992

Official Agent of Industrial Property RUA VICTOR COROON, 10-A 3. "1200 USBOA

Claims (13)

A method for controlling the growth of microbial agents in an aqueous system comprising: a. maintaining in the water a total available chlorine concentration effective for controlling the growth of microbial agents; and b. maintaining a concentration ranging from about 0.1 to about 40.0 ppm glycoluril effective to stabilize the total available chlorine. A method according to claim 1 which comprises maintaining between about 1.0 and about 10.0 ppm glycoluril in water. 33. The method of claim 1 wherein the glycoluril has the formula: wherein R 1, R 2, R 3, R 4, Wherein R 1 is independently selected from the group consisting of hydrogen, lower alkyl radicals having 1 to 2 carbon atoms, 1 to 4 carbon atoms, and phenyl; each X is hydrogen, chlorine or bromine; and a is 0 or 1. A method according to claim 1 characterized in that it comprises maintaining in the water a concentration of at least about 0.6 ppm of total available chlorine. The method of claim 4 which comprises maintaining up to about 10.0 ppm glycoluril in water. The method of claim 5 which comprises maintaining between about 1.0 and about 10.0 ppm glycoluril in water. A method according to claim 6 characterized in that it comprises maintaining between about 1 and about 5 ppm total available chlorine in the water. The method according to claim 1 wherein said glycoluril source composition comprises a composition selected from the group consisting of: glycoluril, alkyl substituted glycoluril, and phenyl substituted glycoluril. A method according to claim 1 characterized in that it further includes the addition to the water of a chlorine stabilizer in addition to the glycoluril, the additional stabilizer being selected from the group consisting of cyanuric acid, oxazolidinone, imidazolidinone, dimethylhydantoin, succinimide , toluenesulfonamide, sulfonamidobenzoic acid, melamine, dioxohexahydrotriazine, piperazinedione, and azodicarbonamidine. 3 10. A method according to claim 1 characterized in that it comprises the addition to water of a first composition comprising a chlorine source composition and the addition to water of a second composition different from the first composition and comprising a glycoluril source composition . The method of claim 10 wherein said second composition essentially consists of a glycoluril source composition. A method according to claim 10 wherein said chlorine source composition comprises a composition selected from the group consisting of: calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, dichloro-s-triazinetrione of sodium, chlorine gas, dichloro-s-triazine-potassium trione, trichloro-s-triazinotrione, bromochlorodimethylhydantoin, dichlorodimethylhydantoin and hypochlorous acid. The method of claim 10 wherein said source glycoluril composition comprises a composition selected from the group consisting of: glycoluril, alkyl substituted glycoluril, phenyl substituted glycoluril, and chloro substituted glycoluril. The method of claim 13 wherein said chlorine source composition comprises a composition selected from the group consisting of: calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinetrione , potassium dichloro-s-triazinotrione, chlorine gas, trichloro-s-triazinotrione, bromochlorodimethylethyantoin, dichlorodimethylhydantoin and hypochlorous acid. 4 15. A method according to claim 10 wherein said chlorine source composition is physically combined with said glycoluryl source composition and said addition comprises simultaneously adding the two compositions to the water. 16. The method of claim 10 wherein said chlorine source composition is physically separated from said source glycoluril composition and said addition comprises the addition of said chlorine source composition and said source composition separately. glycoluril. The method of claim 16 wherein said addition of the chlorine source composition comprises providing a solid material material containing a chlorine source composition, contacting the water with the material in the solid form of a so as to erode the material in a solid form, and gradually erode the material in order to introduce the source chlorine composition into the water. 18. The method of claim 17 wherein the chlorine source composition is selected from the group consisting of: calcium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinotrione, dichloro-s-triazinetriol- potassium, bromochlorodimethylhydantoin, dichlorodimethylhydanedine and trichloro-s-triazinetrione. The method of claim 18 wherein the solid material comprises trichloro-s-triazinetrione. 5 The method of claim 17 wherein said solid material further comprises a source glycoluril composition selected from the group consisting of glycoluril, alkyl substituted glycoluril, phenyl substituted glycoluril, and glycoluril substituted with chloro. A method as claimed in claim 20 wherein said solid material comprises from about 50% to about 99.99% of the source chlorine composition and from about 0.01% to about 50% , 0% of the glycoluril source composition. The method of claim 21 wherein the chlorine source composition comprises trichloro-s-triazinetrione. 23. The method of claim 16 wherein said addition of the glycoluril source composition comprises seeding the glycoluril source composition in the water. The method of claim 23 comprising seeding the source glycoluril source composition in water at a frequency ranging from once a week to once every two weeks. The method of claim 23 wherein the glycoluryl source composition is a composition selected from the group consisting of: glycoluril, alkyl substituted glycoluril, phenyl substituted glycoluril, bromo substituted glycoluril, and glycoluril substituted with chloro. 6 26. A method according to claim 25 wherein said addition of the chlorine source composition comprises providing a material in a solid form containing the chlorine source composition, contacting the water with the solid a method which erodes the material in the solid form, and gradually leads to erosion of the material in order to introduce the source chlorine composition into the water. The method of claim 26 wherein the chlorine source composition is selected from the group consisting of: calcium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinotrione, dichloro-s-triazinotrion-na potassium, bromochlorodimethylhydantoin, dichlorodimethylhydanethine and trichloro-s-triazinetrione. 28. The method of claim 10 wherein the aqueous system is pool water. 29. The method of claim 28 comprising adding the chlorine source composition to maintain between 1.0 and 5.0 ppm the total available chlorine in the pool, and further comprising addition of the glycoluril source composition in order to maintain between about 1.0 and about 10.0 ppm glycoluril in pool water. The method of claim 10 wherein the aqueous system is cooling tower water. 31. A method as claimed in claim 30 comprising adding the chlorine source composition to maintain between 1.0 and about 10.0 ppm the total available chlorine in the cooling tower water, and further comprising adding the glycoluril source composition in order to maintain 7 from about 1.0 to about 10.0 g of glycoluril in the water in the cooling tower. 32. The method of claim 10 wherein said addition of the chlorine source composition and said addition of the glycoluril source composition are carried out at rates that maintain a ppm ratio in the aqueous system between available chlorine and glycoluril from 10 to 1 and about 1 to 10. A method according to claim 32 wherein said addition of the chlorine source composition and said addition of the source glycoluril composition are carried out at rates that maintain a ppm in the aqueous system between chlorine and glycoluril are available in total from about 5 to 1 and about 1 to 5. An improved method for disinfecting aqueous systems, and including maintenance of a total available chlorine concentration effective to control the growth of microbes in the water, characterized in that: maintaining in the water a concentration of glycoluril of about and 0.1 to about 100.0 ppm. The method of claim 34 which comprises maintaining about 1.0 to about 10.0 ppm glycoluril in water. 36. The method of claim 34 which comprises maintaining the total available chlorine in the water at a concentration of at least about 0.6 ppm in the water. 8 The method of claim 34 wherein said maintenance comprises the addition to water of a glycoluril source composition selected from the group consisting of glycoluril, alkyl substituted glycoluril and phenyl substituted glycoluril. A method for stabilizing the total available chlorine present in an aqueous system, the total available chlorine being present in the water in an amount ranging from about 1.0 to about 5.0 ppm, characterized in that the maintenance in the water of a varying concentration from about 0.1 to about 40.0 ppm glycoluril. 39. A method as claimed in claim 38 comprising maintaining between about 1.0 and about 10.0 ppm glycoluril in water. 402 - system of compositions for use in the disinfection of aqueous systems, characterized in that it comprises: a first chlorine source composition adapted for addition to the aqueous system to provide a total available chlorine concentration at a water concentration of from about 1 to about 5 ppm: and a second glycoluril source composition, different from said chlorine source composition, adapted for addition to the aqueous system to provide a concentration of glycoluril in the water ranging from about 0.1 to about 40.0 ppm. The system according to claim 40 wherein said chlorine source composition essentially consists of a composition selected from the group consisting of chlorine gas, calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinetrione , 9 dichloro-s-triazinotrione, bromochlorodimethylhydantoin, dichlorodimethylhydantoin, trichloro-s-triazinotrione and hypochlorous acid. 42S-system according to claim 40, characterized in that said glycoluril source composition essentially consists of a composition selected from the group consisting of glycoluril, alkyl substituted glycoluril, phenyl substituted glycoluril, bromo substituted glycoluril, and substituted glycoluryl with chlorine. The system of claim 42 wherein said chlorine source composition essentially consists of a composition selected from the group consisting of chlorine, calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, dichloro-s-tr sodium triazinotrione, potassium dichloro-s-triazinotrione, bromochlorodimethylhydantoin, dichlorodimethylhydantoin, trichloro-s-triazinotrione and hypochlorous acid. The system of claim 40 characterized in that it comprises a material in the solid form containing said chlorine source composition and adapted to release the source chlorine composition by erosion upon contacting said material in solid form with the water of the aqueous system. The system of claim 44 wherein said solid form material further comprises a glycoluril source composition selected from the group consisting of glycoluril, alkyl substituted glycoluril, substituted phenyl glycoluril, bromo substituted glycoluril, and chloro substituted glycolurils. The system of claim 45 wherein said chlorine source composition essentially consists of a composition selected from the group consisting of calcium hypochlorite, lithium hypochlorite, sodium dichloro-s-triazinetrione, bromochlorodimethylhydantoin , dichloro-dimethylhydantoin, potassium chloro-s-triazinotrione and trichloro-s-triazinetrione. 47a. The system of claim 46 wherein the source chlorine composition is trichloro-s-triazinetrione and said solid-form material comprises from about 50.0% to about 99.99% of the source composition of chlorine and from about 0.01% to about 50.0% of the source glycolitrile composition. Disinfected aqueous system characterized in that it comprises: water; total available chlorine present in the water in a concentration ranging from about 1.0 to about 5.0 ppm; and the glycoluril compound present in the water in a concentration ranging from about 1.0 to about 10.0 ppm. The system of claim 48 wherein said glycoluryl compound is selected from the group consisting of glycoluryl, alkyl substituted glycoluril and substituted phenyl glycoluril. A method for reducing the odor of an aqueous medium treated with chlorine disinfectant in order to control the growth of microbes in the aqueous medium, characterized in that it comprises: maintaining in the aqueous medium a concentration ranging from about 0.1 to about 100, 0 ppm glycoluril. 11 A method for reducing the presence of trihalomethanes in an aqueous medium treated with a chlorine disinfectant in order to control the growth of microbes in the aqueous medium, characterized in that it comprises: maintaining in the aqueous medium a concentration of glycoluril varying between about 0, 1 to about 100.0 ppm. The method of claim 10 wherein said source chlorine composition comprises halogenated dialkylhydantoin. 532. The method of claim 52 wherein said chlorine source composition is bromochloro-dialkylhydantoin or dichlorodialkylhydantoin. The method of claim 10 wherein the aqueous system is selected from the group consisting of pools, hot springs, hot baths, medicinal baths, decorative fountains, recirculation systems for cooling water, systems for dehumidification, tanks, reservoirs and wastewater systems. Lisbon, September 17, 1992 Official Agent of Industrial Property RUA VICTOR CORDON, 10- A 3 ° 1200 LtSBOA