Chemistry: molecular biology and microbiology – Carrier-bound or immobilized enzyme or microbial cell;... – Enzyme or microbial cell is immobilized on or in an...
Reexamination Certificate
2000-07-17
2003-01-07
Naff, David M. (Department: 1651)
Chemistry: molecular biology and microbiology
Carrier-bound or immobilized enzyme or microbial cell;...
Enzyme or microbial cell is immobilized on or in an...
C210S601000, C210S610000, C210S615000, C210S616000, C435S177000, C435S262500
Reexamination Certificate
active
06503740
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to organically modified minerals which are biologically activated. More particularly, the present invention pertains to organically modified mineral materials on which select biologically active organisms are grafted. The present invention also pertains to methods for treating contaminated aqueous material using biologically activated organically modified minerals.
It has been ascertained that many types of bacteria useful in areas such as water purification systems exhibit enhanced growth and activity if permitted to grow on solid substrates. Such substrate—attached systems such as trickling filters and the like require relatively small amounts of maintenance and external care or input to function well.
In contrast, water treatment systems which employ activated sludge methodology or include large fermentation tanks require vast inputs of energy both to maintain the treatment organisms in suspension and to ensure that adequate oxygen is supplied to meet the oxygen demands of the system.
Various methods have been proposed for providing water treatment processes which employ bacteria fixed on solid substrate(s) in order to enhance existing treatment processes and render them more energy and labor efficient. Various substrates have been proposed for this purpose, such as sand or rock. Additionally, U.S. Pat. No. 4,620,929 to Hofmann and U.S. Pat. No. 3,935,067 to Thayer teach the use of expanded clay or plastic materials in combination with bentonite which advantageously exhibits moisture retention characteristics.
Other types of anaerobic filtration systems employ materials such as baked clay, sepiolite, or other clay materials such as vermiculite, attapulgite and the like. These materials have been found advantageous to bacteria fixation. Without being bound to any theory, it is believed that this is due to the presence of trace elements such as copper, zinc and magnesium. These trace elements are electrostatically fixed to the surface of the clay and can serve as nutrients for the bacteria.
Various methods have been proposed for achieving bacteria fixation on the surface of various solid substrates. U.S. Pat. No. 4,177,144 to Hickey et al. teaches pre-inoculation of granulated activated carbon with cellular material. The activated carbon adsorbs organic contaminants in a waste water source. The adsorbed contaminants are, in turn, digested by the bacteria.
Adsorption and bio-degradation are used in tandem to enhance biological treatment of the contaminated water. However, this waste water treatment method does have several drawbacks. As a result of the process, a thin film of biological and biologically-derived material can form around the carbon granules. The phenomenon can result in rapid diminution of adsorption capacity. Additionally, the bacteria will rest on the surface of the granules in a manner which blocks entrance to pores on the surface of the activated carbon preventing adsorption of contaminants in the waste water. Finally, materials such as activated carbon do not supply nutrients which encourage or promote bacterial growth or reproduction.
While cellular material such as bacteria will graft onto clay minerals and other materials, engraftment is enhanced when the material of choice possesses a surface charge such as is the case with both clays and zeolites. In such instances, the adsorption capacity of these minerals for bacteria is the ion exchange capacity.
It has also been found that organically modified materials such as organically modified bentonite or zeolite is efficacious in wastewater treatment processes. When a charged material such as bentonite or zeolite is organically modified, it still retains a good portion of its surface area to which bacteria can attach.
Effective biologically activated organically modified minerals have not been successfully produced. Without being bound to any theory, it is believed that this is due to the toxicity of organic modification agents such as quaternary amines to microbial material such as bacteria.
Thus, it would be desirable and is an object of the present invention to provide an organically modified mineral material which could be employed as a substrate for biologically active cellular material such as bacteria. It is a further object of the present invention to provide an organically modified mineral material which could provide nutrients for the bacteria engrafted thereon. Still further, it is an object of the present invention to provide a biologically activated organically modified material which could be used to reduce contaminants such as PCBs and dioxins from aqueous streams.
SUMMARY OF THE INVENTION
The present invention is directed to a treatment media capable of acting upon at least one chemical contaminant in an aqueous composition and assisting in the decomposition thereof. The treatment media is a biologically activated organically modified material which includes a mineral based substrate, selected from the group consisting of clay, clay analogs, synthetic resins, and mixtures thereof. The mineral based substrate is treated with an organic modification compound selected from the group consisting of quaternary amines, pyridinium compounds, phosphonium amines, and mixtures thereof. At least one strain of bacteria is engrafted to the mineral-based substrate, the bacteria being capable of facilitating decomposition of the chemical contaminant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention is predicated on the unexpected discovery that certain quaternary amines, when employed in context with substrate material are not significantly toxic toward select microbial treatment material such as bacteria. Without being bound to any theory, it is believed that this is due, at least in part, to the mediating nature of the substrate material such as, for example, bentonite or zeolite. It is also believed that these quaternary amines will exhibit an ability to fixate organic compounds in a manner which renders them amenable to bacterial digestion.
In the present invention, as broadly contemplated, micro-organism colonies are engrafted onto a suitable mineral-based substrate which has been organically modified by a suitable quaternary amine compound. The micro-organism colonies are generally made up of bacteria which exhibit ability to digest and/or break down organic pollutants present in an aqueous media to a simpler or more basic compound or compounds. Examples of compounds which can be processed in this manner include, but are not limited to polychlorinated biphenyls (PCB), dioxins, PNAH's, Phenolia, BTEX's, and the like. The microbial agents include various bacterial strains which would be known to those skilled in the art.
The suitable mineral-based substrate of the present invention is contemplated as one which is essentially water stable either in quiescent or agitated media. The material of choice will possess capacity for promoting bacterial engraftment. Preferably, the mineral-based substrate is a clay or clay analog or a synthetic resin suitable for use in water treatment. Suitable clay materials or clay analog materials include clays selected from the group consisting of bentonite, smectite, montmorillonite, paligorskite, attapulgite, sepiolite, saponite, kaolinite, halloysite, hectorite, beidellite and others. Other minerals include zeolites such as chabazite, clinoptilolite, and others. Yet other materials include stevensite, fire clay, ground shale, mud, and silt. Preferably, the clay material will be characterized as having a surface charge. Synthetic and natural materials having a surface charge are also contemplated as being suitable as the substrate of the present invention. It is to be understood that the materials contemplated as being suitable as the substrate, as well as equivalents thereof, may be used either alone, or a mixture of two or more of these materials may be used.
In the preferred embodiment, mineral-based substrate is selected from the group consisting of bentonites, zeolites and mixtures th
Biomin Inc.
Dierker & Glassmeyer, P.C.
Naff David M.
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