| United States Patent Application |
20030189013
|
| Kind Code
|
A1
|
|
Unhoch, Michael Joseph
; et al.
|
October 9, 2003
|
Treatment of circulating water systems
Abstract
The present invention relates to a method of inhibiting the growth of
killing algae, bacteria, yeast and/or fungi in a recirculating water
system which comprises adding to the water a polymeric biguanide and an
adjuvant of the Formula (1) or a salt thereof; wherein: R.sup.1 is an
optionally substituted C.sub.8 to C.sub.12 or C.sub.18 to C.sub.22 alkyl
group; and R.sup.2 and R.sup.3 each independently is H or optionally
substituted C.sub.1-4-alkyl. 1
| Inventors: |
Unhoch, Michael Joseph; (Newcastle, DE)
; Vore, Roy Dean; (Newcastle, DE)
|
| Correspondence Name and Address:
|
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
| Serial No.:
|
296861 |
| Series Code:
|
10
|
| Filed:
|
June 3, 2003 |
| PCT Filed:
|
May 29, 2001 |
| PCT NO:
|
PCT/GB01/02362 |
| U.S. Current Class: |
210/764 |
| U.S. Class at Publication: |
210/764 |
| Intern'l Class: |
C02F 001/68 |
Claims
1. A method for inhibiting the growth of or killing microorganisms
particularly, algae, bacteria, yeast, and/or fungi in a recirculating
water system comprising adding to the water a polymeric biguanide and an
adjuvant of the Formula (1) or a salt thereof: 13wherein: R.sup.1 is an
optionally substituted C.sub.8 to C.sub.12 or C.sub.18 to C.sub.22 alkyl
group; and R.sup.2 and R.sup.3 each independently is H or optionally
substituted C.sub.1-4-alkyl.
2. A method according to claim 1 wherein the adjuvant is selected from the
group consisting of dodecylamine, octadecylamine, N,N-dimethyloctadecylam-
ine or a salt thereof.
3. A method according to claim 1 or claim 2 wherein the adjuvant is added
to the recirculating water system to give a concentration thereof in the
range 0.1 to 30 ppm, preferably 0.5 to 15 ppm.
4. A method according to claim 3 wherein the adjuvant is added to the
recirculating water system to give a concentration thereof in the range 5
to 15 ppm, preferably 6 to 10 ppm.
5. A method according to any one of the preceding claims wherein the
polymeric biguanide contains at least two biguanide units of Formula (2):
14linked by a bridging group which contains at least one methylene
group.
6. A method according to any one of the preceding claims wherein the
polymeric biguanide is a mixture of polymer chains in which the
individual polymer chains, excluding the terminating groups, are of the
Formula (6) or a salt thereof: 15wherein n is from 4 to 40.
7. A method according to any one of the preceding claims wherein the
polymeric biguanide is in the hydrochloride salt form.
8. A method according to any one of the preceding claims wherein the
polymeric biguanide is added to the re-circulating water system to give a
concentration thereof in the water of from 1 to 20 ppm.
9. A method according to claim 8 wherein the polymeric biguanide is added
to the recirculating water system to give a concentration thereof in the
water of from 5 to 12 ppm, preferably 6 to 10 ppm.
10. A method according to any one of the preceding claims wherein the
polymeric biguanide and the adjuvant are added to the recirculating water
system as a composition comprising the polymeric biguanide, the adjuvant
and optionally a carrier.
11. A method according to claim 10 wherein the carrier is a water miscible
organic solvent.
12. A method according to any one of the preceding claims which further
comprises adding one or more further antimicrobial compound(s).
13. A method according to claim 12 wherein the further antimicrobial
compound is a polyquaternary ammonium compound.
14. A method according to claim 13 wherein the polyquaternary ammonium
compound comprises a repeat unit of the Formula (7): 16wherein: R.sup.4,
R.sup.5, R.sup.1 and R.sup.7 each independently is C.sub.1-6alkyl
optionally substituted by hydroxy; Q.sup.2- is a divalent counter ion,
two monovalent counter ions or a fraction of a polyvalent counter ion
sufficient to balance the cationic charge in the repeat unit; and a, b
and t each independently is 1 to 4.
15. A method according to claim 13 or 14 wherein the adjuvant and
polyquaternary ammonium compound are added to the recirculating water
system together as a formulation.
16. A method according to any one of the preceding claims, wherein the
recirculating water system is selected from swimming pool systems, spa
systems, heating systems, cooling systems, cooling towers, domestic
central heating systems, and ornamental ponds.
17. A method for inhibiting the growth of or killing algae microorganisms
particularly, bacteria, yeast, and/or fungi in a recirculating water
system comprising adding to the water in either order or simultaneously:
(i) dodecylamine or a salt thereof; and (ii) a polymeric biguanide;
wherein the dodecylamine is added to the water system to give a
concentration thereof of from 0.1 to 24 ppm and the polymeric biguanide
is added to the water system to give a concentration thereof of from 1 to
20 ppm.
18. A recirculating water system comprising: (i) water, an adjuvant of the
Formula (1) as defined in claim 1 and a polymeric biguanide; and (ii) a
means for recirculating the water; wherein the adjuvant and polymeric
biguanide are dissolved in the water.
19. A kit for treating recirculating water comprising: (i) an adjuvant of
the Formula (1) as defined in claim 1 or a salt thereof; (ii) a polymeric
biguanide; and (iii) instructions for adding (i) and (ii) to a
recirculating water system.
20. A composition comprising: (a) an adjuvant of the Formula (1) as
defined in claim 1 or a salt thereof; and (b) a polymeric biguanide.
21. A composition according to claim 20 wherein the adjuvant of Formula
(1) is selected from the group consisting of dodecylamine,
octadecylamine, N,N-dimethyloctadecylamine or a salt thereof.
22. A composition according to claim 20 or 21 wherein the weight ratio of
component (a) to component (b) is 99:1 to 1:99, preferably from 4:1 to
1:4.
23. A composition according to claim 22 wherein the weight ratio of
component (a) to component (b) is 1:2 to 2:1, preferably 1:1 to 2:1.
24. A composition according to any one of preceding claims 20 to 23 which
further comprises a carrier.
25. A composition according to claim 24 which comprises: (a) from 10 to 60
parts of a mixture of the compound of Formula (1) as defined in claim 1
and a polymeric biguanide; and (b) from 40 to 90 parts of a carrier
wherein the parts (a) and (b) are by weight and the sum of the parts (a)
and (b)=100.
26. A composition according to claim 25 which comprises: (a) from 5 to 30
weight % of the compound of Formula (1) as defined in claim 1 and 5 to 30
weight % polymeric biguanide; and (b) from 90 to 60 weight % carrier.
27. A composition according to claim 24, 25 or 26 wherein the carrier
comprises a water miscible organic solvent.
28. A composition according to any one of claims 20 to 27 which further
comprises one or more further antimicrobial compound(s).
29. A composition according to claim 28, wherein the further antimicrobial
compound(s) comprise from 5 to 50%, preferably from 10 to 30% by weight
of the composition.
Description
FIELD OF INVENTION
[0001] This invention relates to a method for inhibiting the growth of or
killing microorganisms such as algae, bacteria, yeast and/or fungi in a
recirculating water system, to treated recirculating water systems and to
compositions and kits suitable for use in the method.
BACKGROUND OF THE INVENTION
[0002] The water in many industrial and recreational recirculating water
systems such as cooling towers, swimming pools, spas, ornamental ponds,
plumbing, pipework and other surfaces and the like is susceptible to
infection by microorganisms such as bacteria, algae, yeast and fungi.
These organisms may be pathogens or potential pathogens. Thus, for safety
reasons, it is highly desirable to control their growth by the addition
to the water of sanitizing agents. It is also desirable for aesthetic
reasons, to control the growth of non-pathogenic bacteria, algae, yeast
and fungi, particularly the so-called "nuisance" algae, yeast and fungi
which cause discoloration and/or staining of the water and surfaces in
contact with the water
[0003] A variety of sanitising agents have been employed for controlling
undesirable micro-organisms in recreational recirculating water systems.
The most common sanitising agents provide free chlorine and/or bromine
(typically at a concentration in the water of 1 to 5 ppm free halogen).
Chlorine may be provided either directly as chlorine gas or sodium or
calcium hypochlorite or via a chlorine release agent such as a
chlorinated isocyanurate or chlorinated and brominated hydantoin.
Chlorine may also liberated in situ by electrolysis of sodium chloride.
Other sanitising agents which have been used in such systems include
ozone, ozone forming chemicals, hydrogen peroxide, hydrogen peroxide
forming chemicals, copper and/or silver salts which provide copper,
silver or chelated copper ions (typically at a concentration in the water
of 0.1 to 1.0 ppm), quaternary amines and polymeric biguanides,
especially poly(hexamethylene biguanide) (hereinafter referred to as
PHMB) which is typically used at a concentration in recreational water of
6-10 ppm. Systems employing ultra violet light have also been used to
sanitise recirculating water. Sanitising agents are used at higher
concentrations in industrial recirculating water systems and additional
sanitising agents may be used including but not limited to
2-methylisothiazolinone, 5-chloro-2-methylisothiazolinone,
benzisothiazolinone, 2-bromo-2-nitropropane-1,3-diol,
1,2-dibromo-2,4-dicyanobutane, methylene bisthiocyanate,
2-(thiocyanomethylthio)-benzothiazole, formaldehyde and formaldehyde
release agents, glutaraldehyde, dibromonitrilopropionamide and
bromo-hydroxyacetophenone or mixtures thereof.
[0004] Although these primary sanitising agents are very effective in
controlling bacteria they do not always provide consistent control of the
so called "nuisance" algae, yeast and fungi which can cause discoloration
and/or staining of the water and surfaces in contact with the water.
[0005] Examples of "nuisance" algae which are found in swimming pools
include eukaryotic and prokaryotic algae, for example green algae (e.g.
Chlorella spp.), black algae (e.g. Phormidium spp.) and mustard algae
(e.g. Eustigmatos spp.). Of these, we have found that mustard algae are
particularly difficult to control, regardless of the type of primary
sanitising agent used. They appear as slimy deposits attached to the pool
sides and bottom, as well as in the plumbing and in the filter, and vary
in colour from dark green to brown.
[0006] Examples of "nuisance" fungi (often referred to as mold) isolated
from swimming pools include Aspergillus spp., Cladosporium spp., Mucor
spp. and Paecilomyces spp. Paecilomyces lilacinus is the causative agent
in so-called "water mold", "pink mold" and "pink algae". P lilacinus can
manifest itself as white, grey or pink slimy deposits that are found in
niches such as under ladder steps, in skimmer and pump baskets, in
filters and piping. P lilacinus is also found growing in recirculating
water filters where it can have an adverse effect on the efficiency and
lifespan of the filter media. In its mature form, the fungus can also
attach itself to pool surfaces and cause chronic turbidity problems which
are difficult to control.
[0007] Examples of common "nuisance" yeasts found in swimming pools
include Saccharomyces and Candidia species.
[0008] The wide spread occurrence of "nuisance" algae and fungi has lead
to the introduction of methods of controlling these persistent microbes
such as dosing with larger amounts of the sanitiser, shock dosing with
chlorine or the introduction of further sanitisers or additives such as
chelated copper, copper sulfate, combinations of chlorine and ammonium
sulfate,
colloidal silver, linear and/or cyclic quaternary amine
compounds and polyquaternary amine compounds. However, these methods and
algicides/fungicides have shown only limited efficacy against the
"nuisance" algae and fungi and can give rise to undesirable levels of
foam, especially in re-circulating water systems such as spas.
Furthermore, in some circumstances, the additives themselves (especially
chelated copper and copper sulphate) can cause staining of surfaces in
contact with the water.
[0009] Any agent to be added to a recreational water system to control
bacterial growth and "nuisance" algae, yeast and fungi must meet a number
of demanding performance criteria. These include:
[0010] a) an excellent toxicology profile;
[0011] b) reasonable solubility;
[0012] c) freedom from unpleasant taste;
[0013] d) odourless or free from unpleasant odours (post addition);
[0014] e) non-staining of the construction materials e.g. plaster,
plastic;
[0015] f) stability to light;
[0016] g) stability to other additives present in the water (e.g.
sanitisers, H.sub.2O.sub.2 and EDTA);
[0017] h) little or no effect on foaming; and
[0018] i) no adverse effect on water appearance e.g. discoloration or
turbidity.
[0019] Thus, there is a need for a method of treating recirculating water
systems to control not only the growth of pathogens, potential pathogens
and other bacteria, but also the growth of those "nuisance" algae, yeast
and/or fungi which persist in the presence of a primary sanitizing agent.
SUMMARY OF THE INVENTION
[0020] According to the present invention there is provided a method for
inhibiting the growth of or killing microorganisms, particularly
bacteria, algae, yeast, and/or fungi in a recirculating water system
comprising adding to the water a polymeric biguanide and an adjuvant of
the Formula (1) or a salt thereof: 2
[0021] wherein:
[0022] R.sup.1 is an optionally substituted C.sub.8 to C.sub.12 or
C.sub.18 to C.sub.22 alkyl group; and
[0023] R.sup.2 and R.sup.3 each independently is H or optionally
substituted C.sub.1-4-alkyl.
[0024] The Adjuvant
[0025] The alkyl group represented by R.sup.1 may be a branched chain or
more preferably a straight chain alkyl group. It is especially preferred
that R.sup.1 is n-octadecyl or more preferably n-dodecyl.
[0026] When any of R.sup.2 and R.sup.3 is C.sub.1-4-alkyl it may be a
branched chain or more preferably a straight chain alkyl group. Examples
of suitable alkyl groups include ethyl, n-propyl, iso-propyl and
especially methyl. It is preferred however that R.sup.2 and R.sup.3 are
H.
[0027] The alkyl groups represented by R.sup.1, R.sup.2 and R.sup.3 may be
substituted by one or more substituents which do not adversely affect the
activity of the adjuvant when used in combination with a polymeric
biguanide according to the present invention. Suitable optional
substituents include hydroxy, aryl (especially phenyl), amino,
C.sub.1-4-alkoxy, hydroxy-C.sub.1-4-alkoxy or halogen (especially Cl). It
is preferred, however that R.sup.1, R.sup.2 and R.sup.3 are
un-substituted.
[0028] The adjuvant is preferably sufficiently water-soluble to give a
concentration thereof in the recirculating water system which is
sufficient to inhibit the growth of or kill microorganisms such as
bacteria, algae, yeast, and/or fungi present in the recirculating water
system. When the adjuvant is added to a recreational recirculating water
system such as a swimming pool or spa it is also preferable that the
adjuvant has sufficient water solubility not to adversely effect the
appearance of the water in the recirculating water system, for example
water colour or clarity.
[0029] Preferably the adjuvant has a water-solubility of at least 1 ppm,
preferably at least 2 ppm, especially at least 5 ppm more especially at
least 50 ppm and particularly at least 100 ppm. The upper limit of the
adjuvant's water-solubility does not matter, although typically the
adjuvant has a water-solubility below 100,000 ppm, more usually below
25,000 ppm.
[0030] The term "ppm" means parts per million by weight. One may easily
determine the water-solubility of an adjuvant in ppm because this is the
same as the weight of adjuvant in milligrams which will dissolve in 1
litre of water at 20.degree. C. For example if 10 mg of adjuvant
dissolves in 1 litre of water at 20.degree. C. the water-solubility is 10
ppm.
[0031] The solubility of many adjuvants is influenced by pH. In a
recreational recirculating water system the pH is preferably in the range
of from 6.5 to 9.0, more preferably from 6.8 to 8.5 and especially from
7.0 to 8.2. Accordingly the above mentioned preferred solubility of the
adjuvant is the solubility in water at the pH of the recirculating water
system.
[0032] The adjuvant is preferably added to the water system to give a
concentration thereof in the range 0.1 to 30 ppm, more preferably 0.1 to
24 ppm, more preferably 0.5 to 15 ppm, especially 5 to 15 ppm and more
especially 6 to 10 ppm. These preferred concentrations provide good
protection against the growth of microorganisms such as bacteria and
nuisance algae, yeasts and fungi. It is especially preferred that the
concentration of adjuvant is less than 25 ppm, because we have found that
in some circumstances a higher concentration of adjuvant can result in
water turbidity.
[0033] In view of the foregoing preferences the adjuvant is preferably
selected from the group consisting of dodecylamine, octadecylamine,
N,N-dimethyloctadecylamine and salts thereof. It is especially preferred
that the adjuvant is dodecylamine or octadecylamine or a salt thereof.
More especially the adjuvant is dodecylamine or a salt thereof.
Dodecylamine provides good protection against the growth of
microorganisms such as bacteria and "nuisance" algae, yeast and/or fungi
and does not affect water quality, particularly water clarity.
[0034] When the adjuvant is used in the form of a salt, the salt may be
formed with any anion which does not adversely affect the activity of the
adjuvant when used with the polymeric biguanide. Preferably, the salt is
an acid addition salt, more preferably a water-soluble acid addition
salt. The acid forming the salt may be an inorganic acid or an organic
acid. When the acid is an inorganic acid it is preferably hydrochloric
acid.
[0035] When the salt is formed with an organic acid, the acid may contain
a phosphonic, phosphoric, sulphonic or sulphate group but preferably
contains a carboxylic acid group. The organic acid may be aromatic but is
preferably aliphatic, including alicyclic. When the organic acid is
aliphatic, the aliphatic chain of the organic acid may be linear or
branched, saturated or unsaturated, including mixtures thereof.
Preferably, the aliphatic chain is linear and it is also preferred that
the organic acid is an aliphatic carboxylic acid.
[0036] It is preferred that the organic acid contains up to 12, more
preferably up to 6 carbon atoms excluding the acid group.
[0037] The organic acid may contain more than one acid group but it is
preferred that only one such group is present.
[0038] The organic acid may be substituted by a halogen or particularly a
hydroxy group.
[0039] Suitable aliphatic carboxylic acids from which the salt can be
formed include acetic acid, propionic acid, butyric acid, valeric acid,
pivalic acid and lauric acid. Suitable aliphatic di-carboxylic acids
include oxalic acid, malonic acid, succininic acid and gluconic acid.
Suitable hydroxy substituted acids include glycolic acid, lactic acid,
glyceric acid, malic acid and tartaric acid.
[0040] The salts of the adjuvant may be formed using conventional methods,
for example by reacting the compound of Formula (1) with the acid
optionally in the presence of a solvent. The resulting salt may then be
isolated by, for example evaporation. It is preferred that the resulting
salt is purified prior to use in the present method to remove undesirable
impurities.
[0041] A single adjuvant or two or more of the adjuvants may be used in
the present method. The use of two or more of the adjuvants may
advantageously provide a broader spectrum of activity than the use of a
single adjuvant.
[0042] Polymeric Biguanide
[0043] The polymeric biguanide preferably contains at least two biguanide
units of Formula (2): 3
[0044] linked by a bridging group which contains at least one methylene
group. The bridging group preferably includes a polymethylene chain,
optionally incorporating or substituted by one or more hetero atoms such
as oxygen, sulphur or nitrogen. The bridging group may include one or
more cyclic moieties which may be saturated or unsaturated. Preferably,
the bridging group is such that there are at least three, and especially
at least four, carbon atoms directly interposed between two adjacent
biguanide units of Formula (2). Preferably, there are not greater than 10
and especially not greater than eight carbon atoms interposed between two
adjacent biguanide units of Formula (2).
[0045] The polymeric biguanide may be terminated by any suitable group,
such as a hydrocarbyl, substituted hydrocarbyl or by an amine group or by
a cyanoguanidine group of the formula: 4
[0046] When the terminating group is hydrocarbyl, it is preferably alkyl,
cycloalkyl, aryl or aralkyl. When the terminating group is substituted
hydrocarbyl, the substituent may be any substituent which does not
exhibit undesirable adverse effects on the microbiological properties of
the polymeric biguanide. Preferred aryl groups include phenyl groups.
Examples of suitable substituents are aryloxy, alkoxy, acyl, acyloxy,
halogen and nitrile.
[0047] When the polymeric biguanide contains two biguanide groups of
Formula (2), it is preferred that the two biguanide groups are linked
through a polymethylene group, especially a hexamethylene group and the
biguanide is a bisbiguanide.
[0048] The terminating groups in such bisbiguanides are preferably
C.sub.1-10-alkyl which may be linear or branched and optionally
substituted aryl, especially optionally substituted phenyl. Examples of
such terminating groups are 2-ethylhexyl and 4-chlorophenyl. Specific
examples of such bisbiguanides are compounds represented by Formula (3)
and (4) in the free base form: 5
[0049] The polymeric biguanide preferably contains more than two biguanide
units of Formula (2) and is preferably a linear polymeric biguanide which
has a recurring polymeric chain represented by Formula (5) or a salt
thereof: 6
[0050] wherein X and Y represent bridging groups which may be the same or
different and in which together the total of the number of carbon atoms
directly interposed between the pairs of nitrogen atoms linked by X plus
the number of carbon atoms directly interposed between the pairs of
nitrogen atoms linked by Y is more than 9 and less than 17.
[0051] The bridging groups X and Y preferably consist of polymethylene
chains, optionally interrupted by hetero atoms, for example, oxygen,
sulphur or nitrogen. X and Y may also incorporate cyclic moieties which
may be saturated or unsaturated, in which case the number of carbon atoms
directly interposed between the pairs of nitrogen atoms linked by X and Y
is taken as including that segment of the cyclic group, or groups, which
is the shortest. Thus, the number of carbon atoms directly interposed
between the nitrogen atoms in the group 7
[0052] is 4 and not 8.
[0053] The linear polymeric biguanides having a recurring polymer unit of
Formula (5) are typically obtained as mixtures of polymers in which the
polymer chains are of different lengths. Preferably, the number of
individual biguanide units of formulae: 8
[0054] is, together, from 3 to about 80.
[0055] The preferred linear polymeric biguanide is a mixture of polymer
chains in which X and Y are identical and the individual polymer chains,
excluding the terminating groups, are of the Formula (6) or a salt
thereof: 9
[0056] wherein n is from 4 to 40 and especially from 4 to 15. It is
especially preferred that the average value of n is about 12. Preferably,
the average molecular weight of the polymer in the free base form is from
1100 to 3300.
[0057] The linear polymeric biguanides may be prepared by the reaction of
a bisdicyandiamide having the formula: 10
[0058] with a diamine H.sub.2N--Y--NH.sub.2, wherein X and Y have the
meanings defined above or by reaction between a diamine salt or
dicyanimide having the formula: 1 ( H 3 N + - X - N +
H 3 ) ( N - ( CH ) 2 ) 2
[0059] with a diamine H.sub.2N--Y--NH.sub.2 wherein X and Y have the
meanings defined above. These methods of preparation are described in UK
specifications numbers 702,268 and 1,152,243 respectively, and any of the
polymeric biguanides described therein may be used.
[0060] As noted hereinbefore, the polymer chains of the linear polymeric
biguanides may be terminated either by an amino group or by a
cyanoguanidine group: 11
[0061] This cyanoguanidine group can hydrolyse during preparation of the
linear polymeric biguanide yielding a guanidine end group. The
terminating groups may be the same or different on each polymer chain.
[0062] A small proportion of a primary amine R-NH.sub.2, where R
represents an alkyl group containing from 1 to 18 carbon atoms, may be
included with the diamine H.sub.2N--Y--NH.sub.2 in the preparation of
polymeric biguanides as described above. The primary amine acts as a
chain-terminating agent and consequently one or both ends of the
polymeric biguanide polymer chains may be terminated by an --NHR group.
These --NHR chain-terminated polymeric biguanides may also be used.
[0063] The polymeric biguanides readily form salts with both inorganic and
organic acids. Preferred salts of the polymeric biguanide are
water-soluble. When the polymeric biguanide is represented by a compound
of Formula (3) in the free base form, a preferred water soluble salt is
the digluconate. When the polymeric biguanide is represented by a
compound of Formula (4) in the free base form, a preferred water soluble
salt is the diacetate. When the polymeric biguanide is a mixture of
linear polymers represented by Formula (6) in the free base form, the
preferred salt is the hydrochloride.
[0064] It is especially preferred that the polymeric biguanide is a
mixture of linear polymers, the individual polymer chains of which,
excluding the terminating groups, are represented by Formula (6) in the
hydrochloride salt form. This is commercially available from Avecia Inc.
under the trademark BAQUACIL
[0065] The polymeric biguanide is preferably added to the re-circulating
water system to give a concentration thereof in the water of from 1 to 20
ppm, more preferably from 4 to 15 ppm, especially from 5 to 12 ppm, more
especially from 6 to 10 ppm.
[0066] We have found that a combination of a polymeric biguanide
(especially PHMB) with an adjuvant of the Formula (1) or a salt thereof
provides particularly effective control over the growth of bacteria and
nuisance algae, yeast and fungi. Furthermore, the combination of the
polymeric biguanide and adjuvant gives a fast rate of kill of undesirable
micro-organisms. We have also found that the combination of adjuvant and
polymeric biguanide exhibit a high residence time in the water, thereby
providing long term protection against the growth of bacteria and
nuisance algae. A long residence time is desirable because it reduces the
frequency of re-dosing with the polymeric biguanide and/or adjuvant
necessary to sustain protection in the recirculating water system.
[0067] As hereinbefore mentioned the polymeric biguanide and adjuvant may
be added sequentially in any order. However, for ease of dosing it is
preferred that they are added together as a composition comprising the
polymeric biguanide, the adjuvant and optionally a carrier. The carrier,
when present, may be a solid or a liquid medium and may comprise a
mixture of one or more solids or liquids.
[0068] When the carrier is a solid it is preferably a solid which, when
dissolved in the recirculating water system, does not have an adverse
effect upon the water, such as discoloration of the water or causing
turbidity. It is especially preferred that the solid is a water soluble
solid, because this avoids the formation of undesirable deposits in the
recirculating water system. Solid carriers which may be used include, but
are not limited to kaolin, bentonite, kieselguhr, calcium carbonate,
talc, powdered magnesia, china clay or more preferably a water soluble
inorganic salt, or a filler conventionally used in the preparation of
tablets, such as microcrystalline cellulose, lactose and mannitol.
[0069] When the carrier is a solid the adjuvant and polymeric biguanide
may be simply mixed with the carrier to provide a powder formulation
which can be added directly to the recirculating water system.
Alternatively, the powder may be encapusulated in a water-soluble
capsule, for example as is commonly used for encapsulating
pharmaceuticals. This has the advantage that dosing of the powder is
easily controlled, for example a single capsule can be filled with
sufficient powder to give an effective concentration of the polymeric
biguanide and adjuvant in the recirculating water system.
[0070] In an embodiment of the invention the polymeric biguanide and
adjuvant may be used in the form of a tablet. Suitable tablet
formulations include those commonly used for dispensing pharmaceuticals.
The tablets may contain a number of components commonly used in the art
of tablet formulation, for example, fillers, binders, and excipients.
[0071] When the carrier is a liquid medium, the composition is preferably
a solution, suspension, emulsion, dispersion or micro-emulsion of the
polymeric biguanide and adjuvant in the liquid medium.
[0072] The liquid medium is preferably water, a water-miscible organic
solvent or more preferably a mixture of water and one or more
water-miscible organic solvents.
[0073] Suitable water-miscible organic solvents include alcohols,
preferably C.sub.1-6-alkanols, for example methanol, ethanol, propanol
and isopropanol; diols, preferably diols having from 2 to 12 carbon
atoms, for example pentane-1,5-diol, ethylene glycol, propylene glycol,
butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol;
oligo- and poly-alkyleneglycols, for example diethylene glycol,
triethylene glycol, dipropylene glycol, polyethylene glycol (preferably
with an average M.sub.n<1000, more preferably <500) and
polypropylene glycol (preferably with an average M.sub.n<1000);
triols, for example glycerol and 1,2,6-hexanetriol; mono-C.sub.1-4-alkyl
ethers of diols, preferably mono-C.sub.1-4-alkyl ethers of diols having 2
to 12 carbon atoms, for example 2-methoxyethanol, 2-(2-methoxyethoxy)etha-
nol, 2-(2-ethoxyethoxy)-ethanol, 2-[2-(2-methoxyethoxy)ethoxy]ethanol,
2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol and ethyleneglycol monoallylether;
amides, for example N,N-dimethylformamide; cyclic amides, for example
N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and 2-pyrrolidone; and
sulphoxides, for example, dimethylsulphoxide; carboxylic acids, for
example saturated and unsaturated aliphatic monocarboxylic or
dicarboxylic acids for example methanoic, ethanoic, propanoic, butanoic,
2-methylpropanoic, pentanoic, 3-methylbutanoic, 2,2-dimethylpropanoic,
dodecanoic, tetradecanoic, hexadecanoic, octadecanoic, ethandioic,
propanedioic, butanedioic, pentandioic, hexanedioic, heptanedioic,
octanedioic, nonanedioic, and decanedioc acid, unsaturated aliphatic acid
for example propenoic, propynoic, 2-methylpropenoic, trans and
cis-2-butenoic, trans and cis-9-octadecanoic, trans and cis-butenoic and
cis-methylbutenedioic, C.sub.1-6-alkanols and C.sub.1-4 saturated
carboxylic acids are particularly preferred. Especially preferred
water-miscible organic solvents include acetic acid, propanoic acid and
ethanol.
[0074] If the formulation is in the form of a suspension, dispersion or
emulsion, it preferably also contains a surface active agent to produce a
stable dispersion or to maintain the non-continuous phase uniformly
distributed throughout the continuous phase. Any surface active agent
which does not have a significantly adverse effect on the biocidal
activity of the adjuvant and polymeric biguanide may be used. Suitable
surface active agents include emulsifiers and surfactants and mixtures
thereof. The emulsifiers/surfactants may by non-ionic, anionic or a
mixture thereof. Suitable anionic emulsifiers and surfactants include
alkylarylsulfonates (for example calcium dodecylbenzenesulfonate),
alkylsulfates (for example sodium dodecylsulfate), sulfosuccinates (for
example sodium dioctylsulfosuccinate), alkylethersulfates,
alkylarylethersulfates, alkylether carboxylates, alkylarylethercarboxylat-
es, lignin sulfonates or phosphate esters. Suitable non-ionic emulsifiers
and surfactants include fatty acid ethoxylates, ester ethoxylates,
glyceride ethoxylates (for example castor oil ethoxylate), alkylaryl
polyglycol ethers (for example nonylphenol ethoxylates), alcohol
ethoxylates, propylene oxide-ethylene oxide condensation products, amine
ethoxylates, amide ethoxylates, amine oxides, alkyl polyglucosides,
sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters,
polyoxyethylenesorbitol esters or alcohol ethoxy carboxylates, especially
those obtainable from C.sub.12-14-alcohols.
[0075] The weight ratio of the polymeric biguanide:adjuvant may vary over
wide limits, but in many embodiments is from 99:1 to 1:99, preferably
from 4:1 to 1:4, more preferably from 1:2 to 2:1. It is especially
preferred that the weight ratio of the polymeric biguanide to adjuvant is
from 1:1 to 2:1.
[0076] Further improvements in the efficacy of the present method may be
achieved by adding the adjuvant and polymeric biguanide to the
recirculating water system in conjunction with one or more further
antimicrobial compound(s). The addition of further antimicrobial
compound(s) to the recirculating water system can provide a broader
spectrum of antimicrobial activity and/or provide increased efficacy
against particularly problematic algae, bacteria, yeast and/or fungi
present in the recirculating water system. Furthermore, the combination
of the adjuvant compound the polymeric biguanide and one or more further
antimicrobial compound(s) may provide a synergistic effect.
[0077] The further antimicrobial compound(s) may possess anti-bacterial,
anti-fungal, anti-algal or other antimicrobial activity. Suitable further
anti-microbial compounds include agricultural fungicides, agricultural
herbicides, algicides, sanitises, disinfectants or quaternary ammonium
compounds and combinations thereof.
[0078] When the further antimicrobial compound is a sanitising agent the
choice of sanitising agent will depend upon the recirculating water
system in which it will be used. For recreational waters, suitable
sanitising agents include for example chlorine, bromine, ozone, hydrogen
peroxide, calcium hypochlorite, sodium hypochlorite, lithium
hypochlorite, a chlorine release agent (preferably a chlorinated
isocyanurate, or a chlorinated hydantoin, more preferably
dichlorocyanuric acid or trichlorocyanuric acid), a bromine release
agent, a hydrogen peroxide release agent, an ozone release agent or
water-soluble copper or silver or chelated copper salts, (e.g. copper
sulphate, chelated copper sulphate). In industrial recirculating water
systems where the toxicity of the sanitising agent is not so important,
other sanitisers may also be suitable for example 2-methylisothiazolinone-
, 5-chloro-2-methylisothiazolinone, benzisothiazolinone,
2-bromo-2-nitropropane-1,3-diol, 1,2-dibromo-2,4-dicyanobutane, methylene
bisthiocyanate, 2-(thiocyanomethylthio)-benzothiazole, formaldehyde and
formaldehyde release agents, glutaraldehyde, dibromonitrilopropionamide
and bromo-hydroxyacetophenone or mixtures thereof.
[0079] When the further antimicrobial compound is a quaternary ammonium
compound it may be a compound with a single quaternary ammonium group or
a polyquaternary ammonium compound. Examples of suitable quaternary
ammonium compounds include for example, N,N-diethyl-N-dodecyl-N-benzylamm-
onium chloride, N,N-dimethyl-N-octadecyl-N-(dimethylbenzyl)ammonium
chloride, N,N-dimethyl-N,N-didecylammonium chloride,
N,N-dimethyl-N,N-didodecylammonium chloride; N,N,N-trimethyl-N-tetradecyl-
ammonium chloride, N-benzyl-N,N-dimethyl-N-(C.sub.12-C.sub.18alkyl)ammoniu-
m chloride, N-(dichlorobenzyl)-N,-N-dimethyl-N-dodecylammonium chloride,
N-hexadecylpyridinium chloride, N-hexadecylpyridinium bromide,
N-hexadecyl-N,N,N-trimethylammonium bromide, N-dodecylpyridinium
chloride, N-dodecylpyridinium bisulphate, N-benzyl-N-dodecyl-N,N-bis(beta-
-hydroxy-ethyl)ammonium chloride, N-dodecyl-N-benzyl-N,N-dimethylammonium
chloride, N-benzyl-N,N-dimethyl-N-(C.sub.12-C.sub.18 alkyl) ammonium
chloride, N-dodecyl-N,N-dimethyl-N-ethylammonium ethylsulphate,
N-dodecyl-N,N-dimethyl-N-(1-naphthylmethyl)ammonium chloride,
N-hexadecyl-N,N-dimethyl-N-benzylammonium chloride or
N-dodecyl-N,N-dimethyl-N-benzylammonium chloride.
[0080] In a preferred embodiment the further antimicrobial compound is a
polyquaternary ammonium compound. Antimicrobial polyquaternary ammonium
compounds which may be used include those described in U.S. Pat. Nos.
3,874,870, 3,931,319, 4,027,020, 4,089,977, 4,111,679, 4,506,081,
4,581,058, 4,778,813, 4,970,211, 5,051,124, 5,093,078, 5,142,002 and
5,128,100 which are incorporated herein by reference thereto.
[0081] Especially preferred polyquaternary compounds comprise a repeat
unit of the Formula (7): 12
[0082] wherein:
[0083] R.sup.4, R.sup.5, R.sup.6 and R.sup.7 each independently is
C.sub.1-6-alkyl optionally substituted by hydroxy;
[0084] Q.sup.2- is a divalent counter ion, two monovalent counter ions or
a fraction of a polyvalent counter ion sufficient to balance the cationic
charge in the repeat unit; and
[0085] a, b and t each independently is 1 to 4.
[0086] Preferably Q.sup.2- is two monovalent anions selected from a halide
anion and a trihalide anion, more preferably chloride or bromide.
[0087] R.sup.4, R.sup.5, R.sup.6 and R.sup.7 are preferably each
independently C.sub.14-alkyl, more preferably methyl.
[0088] a, b and t are preferably each independently 1, 2 or 3. It is
especially preferred that a, band tare 2.
[0089] The polyquaternary ammonium compound with the repeat unit of
Formula (7) preferably has a average molecular weight of from 1,000 to
5,000. An especially preferred polyquaternary ammonium compound with a
repeat unit of Formula (7) is poly(oxyethylene-(dimethyliminio)ethylene(d-
imethyliminio)ethylenedichloride). This polymer is commercially available
under the Trademark WSCP from Buckman Laboratories Inc.
[0090] We have found that the use of a polyquaternary ammonium (especially
poly(oxyethylene-(dimethyliminio)ethylene(dimethyliminio)ethylene
dichloride)) in addition to the polymeric biguanide and adjuvant provides
good protection against the growth of algae, especially those commonly
found in recreational waters such as swimming pools.
[0091] This combination is particularly useful as a remedial treatment for
algal blooms in recreational waters.
[0092] When the further antimicrobial compound is a polyquaternary
ammonium compound it is convenient to add the adjuvant and polyquaternary
ammonium compound to the recirculating water system together as a
formulation. Such formulations are commercially available, for example
Busan .sub.20/.sub.20T.TM. (ex Buckman Laboratories Inc.) is a
formulation comprising poly(oxyethylene-(dimethyliminio)ethylene(dimethyl-
iminio)ethylene dichloride) and a salt of dodecylamine.
[0093] Alternatively, the further antimicrobial compound may be added to
the recirculating water system together with the adjuvant and polymeric
biguanide together as a composition comprising optionally a carrier. The
carrier, when present, may be a solid or a liquid medium. Suitable solid
and liquid carriers which may be employed are as previously described.
When a further antimicrobial compound is present in such a composition,
the further antimicrobial compound typically comprises from 5 to 50%, and
preferably from 10 to 30% by weight of the composition.
[0094] The Recirculating Water System
[0095] The invention is applicable to any industrial or recreational
recirculating water system but is especially suitable for recreational
recirculating water systems. Examples of industrial water systems include
heating and cooling systems, e.g. cooling towers and domestic central
heating systems. Examples of recreational recirculating water systems
include swimming pools, spas and ornamental ponds. The invention is also
applicable to plumbing, pipework and other surfaces which form part of
the industrial or recreational recirculating water systems and which are
susceptible to infection by microorganisms.
[0096] Best Mode
[0097] A preferred embodiment comprises a method for inhibiting the growth
of or killing microorganisms, particularly algae, bacteria, yeast, and/or
fungi in a recirculating water 35 system, preferably a recreational
recirculating water system, comprising adding to the water in either
order or simultaneously:
[0098] (i) dodecylamine or a salt thereof; and
[0099] (ii) a polymeric biguanide, especially PHMB;
[0100] wherein the dodecylamine adjuvant is added to the water system to
give a concentration thereof of from 0.1 to 24 ppm, preferably 0.5 to 15
ppm, more preferably 6 to 15 ppm and especially 6 to 10 ppm, and the
polymeric biguanide is added to the water system to give a concentration
thereof of from 1 to 20 ppm, preferably 5 to 12 ppm more preferably 6 to
10 ppm.
[0101] The combination of components (i) and (ii) provides very effective
protection against the growth of microorganisms such as bacteria and
"nuisance" algae, yeast and/or fungi without affecting water quality,
especially water clarity.
[0102] Recirculating Water Systems
[0103] According to a second aspect of the present invention there is
provided a recirculating water system comprising (i) water, an adjuvant
of the Formula (1) as hereinbefore defined and a polymeric biguanide; and
(ii) a means for recirculating the water; wherein the adjuvant and
polymeric biguanide are dissolved in the water.
[0104] The preferred adjuvant and polymeric biguanide, their preferred
amounts and the preferred water systems are as defined above in relation
to the first aspect of the present invention.
[0105] The preferred means for recirculating the water comprises a pump.
[0106] Composition
[0107] According to a third aspect of the present invention there is
provided a composition comprising:
[0108] (i) an adjuvant of the Formula (1) as hereinbefore defined;
[0109] (ii) a polymeric biguanide; and
[0110] (iii) optionally a carrier.
[0111] The preferred adjuvants, polymeric biguanides and carriers, and
weight ratio of polymeric biguanide:adjuvant are as hereinbefore
described in relation to the first aspect of the present invention.
[0112] In a preferred embodiment of the invention the composition
comprises:
[0113] (a) from 10 to 60 parts of a mixture comprising the compound of
Formula (1) and a polymeric biguanide; and
[0114] (b) from 40 to 90 parts of a carrier wherein the parts (a) and (b)
are by weight and the sum of the parts (a) and (b)=100.
[0115] Preferably the compositions comprises:
[0116] (a) from 5 to 30, more preferably 10 to 20 weight % of the compound
of Formula (1) and from 5 to 30, more preferably 10 to 20 weight % of
polymeric biguanide; and
[0117] (b) from 90 to 60 more preferably 80 to 40 weight % of carrier.
[0118] The compositions may be used to treat recirculating water systems,
for example industrial and recreational recirculating water systems.
[0119] Kits
[0120] According to a fourth aspect of the present invention there is
provided a kit for treating recirculating water comprising:
[0121] (i) an adjuvant of the Formula (1) as hereinbefore defined;
[0122] (ii) a polymeric biguanide; and
[0123] (iii) instructions for adding (i) and (ii) to a recirculating water
system, preferably to a swimming pool, spa or ornamental pond. The
instructions preferably comprise instructions to use (i) and (ii) for
inhibiting the growth of and/or killing microorganisms such as algae,
bacteria, yeast and/or fungi.
[0124] The invention is further illustrated by the following examples in
which all parts and percentages are by weight unless otherwise indicated.
EXAMPLES 1 TO 6
Preventative Laboratory Studies on Algae
[0125] Pre-Amble
[0126] Preventative treatments, as the name implies, are intended to
prevent an outbreak occurring. Without adequate control measures,
outbreaks can occur in two different scenarios. In the first scenario,
the organism is present at all times but the concentration of the
organism is so low that it is not noticeable. If a triggering event
occurs, the organism reproduces rapidly resulting in a "bloom". Examples
of triggering events are pH shifts, disturbance of a harbouring biofilm
in the filter or plumbing, and introduction of additional but previously
limited nutrients, such as nitrogen.
[0127] In the second scenario, low numbers of organisms can be introduced
into a previously non-colonized pool that having optimal growth
conditions. The combination of organisms and optimal growth conditions
can result in a "bloom". The organisms can be introduced by the fill
water, atmospheric dust, rainfall, or by bathing suits which have been
previously used in infected pools or rivers and not washed before re-use.
[0128] In preventative laboratory treatment studies, growth conditions are
optimised to support a bloom. An experimental flask is prepared with a
medium having optimised growth conditions to support a bloom, the medium
in the flask is treated with a prescribed concentration of a test
formulation, and then inoculated with a low concentration of a
bloom-forming organism. The medium is monitored for a period of time to
observe whether the formulation is effective at preventing an algal
bloom.
[0129] These studies used the most problematic organisms, i.e. field
isolated mustard algae. Any compound that shows good efficacy against
such organisms would be expected to provide even better control against
the less environmentally-robust green and black algae.
[0130] Experimental
[0131] A series of innocula of naturally occurring mustard algae was
prepared by inoculating flasks of modified Jaworski's medium with
un-purified wild algal isolates collected in the field and containing low
levels of bacteria and culturing the flasks for two weeks. The
Jawaorski's medium was modified by the addition of 4 ppm
polyhexamethylene biguanide (PHMB) (ex Avecia Inc.) to inhibit the growth
of the bacteria present in the algal isolates. The inocula were harvested
by aseptic vacuum filtration and the concentration of algal cell masses
were combined ("pooled") and redispersed in a aseptic medium to provide a
concentrated pooled inoculum. The amount of inoculum used was varied to
achieve an initial optical density of 0.010 in the test flasks. The
optical density was determined using a Milton Roy Spec 20
spectrophotometer.
[0132] Test adjuvants and Busan 20/20.TM. (ex Buckman Laboratories Inc. a
mixture of dodecylamine and a polyquaternary ammonium compound
(WSCP.TM.)) were assessed, in triplicate, for anti-algal activity and a
blank control, by adding each adjuvant or known Busan 20/20.TM. at 0 ppm
and 15 ppm to Jaworski's medium (50 ml) contained in 125 ml flasks
containing 6 mm borosilicate beads (50). Each flask was then inoculated
with a prescribed amount of the pooled inoculum, so that the liquid in
the flask had no visible green cast. The flasks (including a control or
blank containing no adjuvant or Busan 20/20.TM. were closed with
translucent caps and incubated at 80 F for 10 days with 18 hours/day of
illumination by a combination of fluorescent grow lamps and standard
incandescent lamps. The incubation time was 10 days. Growth was scored by
visual observation on a 0-4 scale and the results are shown in Table 1
below. A score of "1" indicates that the flask is slightly green. A score
of "2" indicates that bloom has begun. A score of "4" indicates that the
flasks are too turbid to see through. Any score >1 is considered a
preventative failure.
1TABLE 1
Visual score - Preventive Algae Control
Adjuvant PHMB Average
Example Adjuvant Conc. (ppm) Conc.
(ppm) Visual 10000Score Comments
1 Dodecylamine 2.5 4.0 0
no visible growth
2 Dodecylamine 5.0 4.0 0 no visible growth
3 Dodecylamine 10.0 4.0 0 no visible growth
4 Dodecylamine 15.0
4.0 0 no visible growth
5 Busan 20/20 .TM. 10.0 4.0 0 no visible
growth
6 Busan 20/20 .TM. 15.0 4.0 0 no visible growth
Control None 0 4.0 4.0 very heavy growth
Control None 0 0 4.0 very
heavy growth
[0133] The data in Table 1 clearly illustrates the effectiveness of the
combinations of PHMB and dodecylamine and PHMB and Busan 20/20.TM. over
the PHMB, alone, at preventing the field isolated mustard algae outbreak
from occurring.
EXAMPLES 7 TO 12
Remedial Laboratory Studies on Algae
[0134] Pre-Amble
[0135] Remedial treatments are intended to reduce a bloom of algae once it
has already occurred. During blooms the algal infestation of the system
is obvious, even to the casual observer. Effective remedial treatments
are those that reduce the obvious symptoms, even if they do not result in
a complete kill of the algae. Remedial treatments are considered
effective if they return the system to a pre-bloom state.
[0136] Remedial efficacy was evaluated in this example using field
isolated mustard algae. Any treatment showing good control of this
organism is expected to display similar efficacy against green and black
algae.
[0137] Experimental
[0138] Studies were conducted in 125 ml flasks containing 6 mm
borosilicate glass beads (50) and Jaworski's medium (50 ml). The flasks
were inoculated with pooled cultures of mustard algae to achieve an
initial absorbance of 0.10, as measured using a Milton Roy Spec 20
Spectrophotometer. This concentration of algae in the water resulted in a
noticeable green colour similar to that seen after brushing pools with
moderate blooms. The adjuvants identified in Table 2 were added at levels
of 1.25 and 2.5 ppm active ingredient. Busan 20/20.TM. identified in
Table 3 was added at levels of 0.625, 1.25, 2.5 and 5.0 ppm. The
performance of the adjuvants were compared to the controls with and
without PHMB. The flasks were closed using translucent caps, illuminated
for 8 hours using a combination of fluorescent grow lamps and standard
incandescent lamps each day and incubated at 80.degree. F. for a period
of 5 days. Algal growth was measured after 5 days using a Milton Roy Spec
20 spectrophotometer. The higher the optical density the heavier the
growth. Treatments that result in a terminal optical density of less than
0.2 display either algistatic or algicidal activity. The results are
shown in Table 2.
2TABLE 2
Remedial Algae Control
Adjuvant
PHMB Average
Example Adjuvant Conc. (ppm) Conc. (ppm) Optical
Density Comments
7 Dodecylamine 2.5 4.0 0.12 Control
(Armeen 12 D .TM.)
8 Dodecylamine 1.25 4.0 0.08 Excellent
(Armeen 12 D .TM.) Control
9 Octadecylamine 2.5 4.0 0.08
Excellent
(Armeen 18 D .TM.) Control
10 Octadecylamine
1.25 4.0 0.16 Control
(Armeen 18 D .TM.)
11
Dimethyloctadecylamine 2.5 4.0 0.07 Excellent
(Armeen DM 18 D
.TM.) Control
12 Dimethyloctadecylamine 1.25 4.0 0.12 Control
(Armeen DM 18 D)
Control None 0 4.0 0.62 Very heavy
growth
Control None 0 0 0.48 Heavy growth
Footnote to Table 2: Armeen 12 D, Armeen 18 D and Armeen DM are trademark
names for dodecylamine, octadecylamine and dimethyloctadecylamine ex Akzo
Nobel.
[0139] The data in Table 2 shows that all of the combinations of adjuvants
and PHMB were successful at significantly reducing the growth of the
field isolated mustard algae and much more effective than the PHMB by
itself. Also, there was no significant difference in the performance of
the straight chained octadecylamine and dimethyloctadecylamine at 2.5
ppm.
Example 13
Effect of an Additional Polyquaternary Ammonium Compound on the Control of
Algal Growth
[0140] The experiments described in Examples 7 to 9 were repeated except
that in place of the dodecylamine Busan 20/20.TM. (a mixture of
dodecylamine and a polyquaternary 5 ammonium compound available under the
trademark WSCP ex Buckman Laboratories Inc.) was used. The results are
shown in Table 3.
3TABLE 3
Remedial Algae Control
PHMB
Average
Conc. Conc. Optical
Example Adjuvant (ppm)
(ppm) Density Comments
13 Busan 0.625 4.0 0.32 Moderate
growth
20/20 .TM.
14 Busan 1.25 4.0 0.20 Slight growth
20/20 .TM.
15 Busan 2.5 4.0 0.16 Control
20/20 .TM.
16 Busan 5.0 4.0 0.12 Control
20/20 .TM.
Control None
0 4.0 0.81 Very heavy growth
Control None 0 0 0.51 Heavy growth
[0141] The data in Table 3 shows that at concentrations of Busan 20/20.TM.
greater than or equal to 1.25 ppm in combination with PHMB gave a
significant improvement over PHMB alone.
Example 17
Effect of Adjuvant on Water Clarity
[0142] When treating recreational waters such as swimming pools or spas it
is highly desirable to add an agent to the water which can be dosed in
one application or will accumulate over time and will not adversely
effect the water quality, for example clarity, colour, foaminess, or
objectionable odour or taste. If swimming pool water is not clear it
could present a hazard to swimmers who may not be able to see the pool's
sides or bottom.
[0143] Experimental
[0144] Six 10 gallon fish aquariums equipped with a heater and a
recirculating pump (to simulate a swimming pool environment) were filled
with simulated swimming pool water containing polyhexamethylene biguanide
(PHMB) comprising:
4
Sodium bicarbonate (total alkalinity) 80-150 ppm
Calcium chloride (hardness) 180-275 ppm
Hydrogen peroxide 25-30
ppm
Polyhexamethylene biguanide (PHMB) 6-12 ppm
[0145] To these tanks was added the adjuvant shown in Table 4. The pH of
the tanks was maintained between 7.2 and 7.8 and the water temperature
was maintained at 70.+-.3.degree. F. After the chemical additions the
water was circulated for 24 hours. The water in each tank was then
visually inspected and tested for turbidity using a Hach Turbidimeter.
The results are shown in Table 4.
5TABLE 4
Effect of Dodecylamine and Tetradecylamine
on Water Clarity
Adjuvant
Concentration Turbidity
Visual
Tank Adjuvant (ppm) (NTU) Observations
1
Control 0 2.3 Clear
2 Dodecylamine 2.5 2.7 Clear
3
Dodecylamine 5.0 1.8 Clear
4 Dodecylamine 10.0 2.5 Clear
5
Tetradecylamine 5.0 10.1 Cloudy
6 Tetradecylamine 10.0 19.0 Cloudy
[0146] The results in Table 4 clearly indicate that the dodecylamine had
no effect on water clarity whereas tetradecylamine resulted in water
turbidity.
