Compositions – Fire-extinguishing – Foam or gas phase containing
Reexamination Certificate
1999-11-03
2003-03-04
Cooney, Jr., John M. (Department: 1711)
Compositions
Fire-extinguishing
Foam or gas phase containing
C252S002000, C424S093400, C521S065000
Reexamination Certificate
active
06527970
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved formulation both for extinguishing fires and for decomposing (bioremediating) residual organic materials, including hydrocarbons, that were fueling the fire or that continue to create a hazard after the fire is extinguished. In particular, the present invention relates to an aqueous film forming foam (AFFF) fire-fighting formulation that also biodegrades in situ the residual hydrocarbons remaining at a fire site after the fire is extinguished, including biodegrading certain of the components of the fire-fighting formulation.
BACKGROUND OF THE INVENTION
Without limiting the scope of the invention, its background is described in connection with uses of foaming concentrates for use as fire-fighting agents. Foaming concentrates for use as fire-fighting agents have been known and used since before 1940. Additional ingredients are added to such concentrates for a variety of reasons. For example, because such concentrates contain organic or proteinaceous foaming agent, microbicides (bactericides) are added to the concentrate to kill or prevent bacteria which would decay the foaming agent. Some typical foam fire-fighting formulations produce a foam that may persist for up to several days. Persistent foams have utility for such applications as temporary covers for landfills and waste piles, vapor barriers for spills of hazardous materials, and crop protection against frost. The presence of a bactericide in the foam to prevent the decomposition of the foam by bacteria promotes the persistence of the foam.
Examples of protein hydrolysates as a constituent of prior art foam formulations include U.S. Pat. No. 5,225,095 to DiMaio, and also U.S. Pat. No. 5,133,991 to Norman et al. Because these hydrolysates are excellent nutrient sources for microbiological life forms, a low-level toxicity microbicide or bactericide is usually recommended as an additive to preserve the concentrate. The fact that most foams are susceptible to microbial decomposition provides a basis for the conclusion that the art of fire-fighting foams teaches against the inclusion of microbial life forms in their formulations.
Organics decomposing microorganisms have been commercially available to clean oil spills from oil tankers and to assist in waste removal from grease interceptors in restaurants for some time now. Microbes specifically engineered for the decomposition of difficult organic compounds are well known and readily available.
Investigation of microbial degradation of oil dates back to at least 1942, when the American Petroleum Institute began to subsidize research in the field. Considerable basic knowledge about factors that affect natural biodegradation, the kinds of hydrocarbons capable of being degraded, and the species and distribution of the microorganisms involved in biodegradation had already been developed in the early 970s. For instance, the Office of Naval Research sponsored more than a dozen basic and applied research projects in the late 1960s and early 1970s on oil biodegradation to control marine oil spills. Since this time, a large number of refineries, tank farms, and transfer stations now employ in situ bioremediation to restore land contaminated by accidental spills of fuel oil or other hydrocarbons.
An important series of field tests of the use of fire-fighting foam to control organics and hydrocarbon fires were conducted in the aftermath of the Persian Gulf War. The oil field fires created an environment of urgency and necessity which focused creative minds on solving the problems at hand, and on concentrating on research and development to solve some of the problems anticipated to occur again in the future.
The difficulties encountered in incorporating microbe cultures in a fire-fighting foam solution which will extinguish organically fueled fires and begin the disposal of the residual hydrocarbon waste products were many. The first challenge was the selection of a hardy strain of organics-consuming (primarily hydrocarbon-consuming) microorganisms that can withstand the extremely severe environment associated with organically fueled fires in a proportion sufficient to adequately address the magnitude of the overall bioremediation challenge presented. A second challenge was determining the specific organism that digest or decompose a particular grease or oil and yet remain capable of being stabilized so that they have a satisfactory shelf life thereby being available when needed. A third challenge was the selection of a microbial strain that be stable in surfactant mixtures strong enough to extinguish the fire.
A need, therefore, exists for a bioremediating fire-fighting foam mixture and a method for the decomposition of organic materials which meets the challenges presented in order to reduce cleanup costs and increase the quality of the cleanup by providing an effective and environmentally safe means to do so.
SUMMARY OF THE INVENTION
The object of the present invention is to provide effective fire-fighting formulations that initiate bioremediation of the site of the fire. Generally, the invention is an aqueous formulation which includes preselected bioremediation agents in a fire-fighting foam-forming composition.
In one embodiment of the present invention, a composition for extinguishing fires and bioremediating a fire site is provided comprising a foam-forming surfactant component and a bioremedial component comprising one or more sporogenous nonpathogenic bacteria species. By foam-forming surfactant component is meant one or more surfactants including if desired mixtures of surfactants including anionic, cationic, non-ionic, and amphoteric surfactants. Certain of these surfactants may be fluorinated surfactants that provide a film-forming foam.
The bioremediation component comprises a biological agent having the characteristics: 1) the ability to at least partially degrade flammable organic materials; 2) the ability to remain viable in fire-fighting, foam-forming and the film-forming foam formulations; and 3) lack of pathogenicity in humans of normal vulnerability. Suitable microorganisms utilized in one embodiment of the present invention may include, for example, sporogenous bacteria embodying the desired characteristics. Certain commercially available sporogenous Bacillus strains, for example, include Bacillus formulated by Sybron Chemicals, Inc. Bacillus are a gram-positive bacterium which, under certain conditions, are spore-forming. Examples of Bacillus strains effective in the practice of the invention in connection with the consumption of volatile organic compounds include but are not limited to
B. subtilis, B. licheniformis, B. polymyxa
(now
Paenibacillus polymyxa
),
B. amyloliquifaciens, B. pasteurii
and
B. laevolacticus.
In addition, the selection among the above strains is advantageous because these species of Bacillus are not true pathogens as are the species
B. anthracis
and
B. cereus
. Reports of infections in man caused by Bacillus species other than
B. anthracis
and
B. cereus
are rare. According to a report by the Department of Biology of the Virginia Polytechnic Institute and State University,
B. subtilis, B. licheniformis
, and
B. polymyxa
as described by the manufacturer, Sybron, would not constitute a public health hazard unless the microorganisms were used in an area where individuals with an unusual vulnerability (such as with open wounds or immunodeficiency) would be exposed. Similarly,
B. amyloliquifaciens, B. pasteurii
and
B. laevolacticus
are considered not to constitute a public health hazard because they are not
B. anthracis
or
B. cereus
species.
Microorganisms (microbes) of the type used in the present invention are capable of assimilating and breaking down the non-soluble organic materials including hydrocarbons that compose grease and oil into relatively harmless substances of water-soluble products, carbon dioxide and a lesser quantity of fatty acids. The bacterial component may consist essentially of bacteria in aqueous solution or may include additional com
Cox Charles S.
Scogin William L.
Cooney Jr. John M.
Haynes and Boone LLP
Montgomery John W.
Verde Environmental, Inc.
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