Plant protecting and regulating compositions – Plant growth regulating compositions – Aquatic plant regulator
Reexamination Certificate
2001-02-06
2004-03-23
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Aquatic plant regulator
C504S154000, C504S155000, C504S157000, C504S158000
Reexamination Certificate
active
06710017
ABSTRACT:
FIELD OF INVENTION
The present invention relates to compositions and methods for treating recirculating water systems to inhibit the growth of or kill algae and kits suitable for use in the methods of the present invention.
BACKGROUND OF THE INVENTION
The water in many industrial and recreational recirculating water systems such as cooling towers, swimming pools, spas, ornamental ponds and the like is susceptible to contamination by 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 of sanitizing agents to the water. 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.
A variety of sanitizing agents have been employed for controlling undesirable microorganisms in recreational recirculating water systems. The most common sanitizing 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, sodium or calcium hypochlorite or via a chlorine release agent such as a chlorinated isocyanurate or chlorinated hydantoin. Chlorine may also liberated in situ by electrolysis of sodium chloride. Other sanitizing 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 ultraviolet light have also been used to sanitize recirculating water. In industrial recirculating systems, sanitizing agents are used at higher concentrations and other sanitizing 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.
Although these sanitizing agents are very effective in controlling bacteria, they do not suitably control the growth of the so-called “nuisance” algae, which can cause discoloration and/or staining of the water and surfaces in contact with the water.
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, mustard algae are particularly difficult to control, regardless of the type of sanitizing agent used.
The widespread occurrence of “nuisance” algae has lead to the introduction of methods of controlling these persistent microbes such as dosing with larger amounts of the sanitizer, shock dosing with chlorine or the introduction of further sanitizers 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 algaecides have shown only limited efficacy against the “nuisance” algae 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.
Any anti-algal agent to be added to recreational water systems to control “nuisance” algae, must meet a number of demanding performance criteria. These criteria include:
a) an excellent toxicology profile;
b) reasonable solubility;
c) freedom from unpleasant taste
d) odorless or free from unpleasant odors;
e) non-staining of construction materials e.g. plaster, plastic;
f) stability to light;
g) stability to other chemicals which may be present in the recirculating water system, for example sanitizers, water clarifiers, oxidizing agents and chelating agents;
h) little or no effect on foaming; and
i) no adverse effect on water appearance e.g. discoloration or turbidity.
It has been proposed to add herbicides such as Simazine™ (CAS number 122-34-9, 6-chloro-N2,N4-diethyl-1,3,5-triazine-2,4-diamine) or Erase™ (CAS number 5915413, 1,3,5-triazine-2,4-diamine, 6-chloro-N-(1,1 -dimethylethyl)-N′-ethyl-2-tert-butylamino-4-chloro-6-ethylamino-s-triazine) to recreational waters in order to control the “nuisance” algae. However, such chemicals have relatively high mammalian toxicity at the levels required to control the algae, and are thus not suitable in practice for this purpose.
In addition, the following herbicides and agricultural fungicides are not considered within the scope of the invention for controlling the growth of nuisance algae in recirculating water systems:
(i) the herbicide 2-chloro-4,6-diamino-s-triazine of the Formula (1) as disclosed in U.S. Pat. No. 4,659,359 used in combination with active halogen or an agent which releases active halogen;
(ii) the herbicide 4-fluoroalkyl diphenylether as described in U.S. Pat. No. 5,158,596 at col. 3, lines 10 to 40 used in combination with a material selected from the group consisting of sodium hypochlorite, halodialkylhydantoin, n-alkyl dimethyl benzylammonium chloride, 2,2-dibromo-3-nitrilopropionamide, 2-bromo-2-nitro-1,3-propanediol, poly[oxyethylene(dimethylimino)ethylene(dimethylimino)ethylene dichloride], 3-iodo-2-propynylbutylcarbamate, sodium N-methyldithiocarbamate, zinc bis(dimethyldithiocarbamate), p-tolyldiiodomethylsulfone and a fatty acid salt;
(iii) when the herbicide is used in a swimming pool in combination with iodine, the herbicide is not one of those disclosed in Table 1, page 817, of
Applied and Environmental Microbiology,
1977 Vol. 34, no 6;
(iv) when the herbicide is used in an industrial recirculating water system, it is not a methylthiotriazine derivative of the Formula (1) as described in JP 09 328405 used in combination with 3-(3,4-dichlorophenyl)-1,1-dimethylurea or 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea;
(v) the herbicide is not Simazine™ (CAS number 122-34-9, 6-chloro-N2,N4-diethyl-1,3,5-triazine-2,4-diamine) or Erase™ (CAS number 5915413, 1,3,5-triazine-2,4-diamine, 6-chloro-N-(1,1-dimethylethyl)-N′-ethyl-2-tert-butylamino-4-chloro-6-ethylamino-s-triazine);
(vi) the agricultural fungicide is not a flavenoid aldehyde or alcohol of the Formula (1) described in U.S. Pat. No. 5,738,861; and
(vii) when the agricultural fungicide is used in a swimming pool in combination with iodine, it is not one of those disclosed in Table 1, page 817, Applied and Environmental Microbiology,1977 Vol. 34, no 6.
None of these have been successful in controlling the growth of nuisance algae in recirculating water systems.
Thus, there is and remains a need for compositions and methods of treating recirculating water systems to control the growth of those “nuisance” algae which persist in the presence of a sanitizing agent.
SUMMARY OF THE INVENTION
According to the present invention, there are provided compositions and methods for inhibiting the growth of or killing algae, particularly nuisance algae, in a recirculating water system comprising adding to the water a compound having anti-algal activity selected from the group of a herbicide or an agricultural fungicide and combinations thereof, said compound having the desired anti-algal activity with respect to the nuisance algae described above.
By way of the present invention, kits containing compounds or compositions for controlling the growth
Unhoch Michael J.
Vore Roy D.
Avecia Inc.
Clardy S. Mark
Law Offices of John A. Parrish
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