FIELD OF THE INVENTION The present invention relates to a method of dissolving and cleaning human waste from waste containers and the like. More specifically, the invention relates to a method of preparing a cleaning solution to be used for cleaning containers for human waste, and the like.

BACKGROUND OF THE INVENTION It is often necessary to treat human waste in holding tanks on boats, recreation vehicles (RV's), portable toilets, trains, airplanes and household septic tanks. The waste held in these tanks must be broken down into relatively harmless by-products and the odor somewhat neutralized.

Due to the proteinaceous nature of the soils common to waste that must be treated, the use of proteolytic enzymes has been shown effective in improving the breakdown and removal of these materials from the waste. The use of a proteolytic enzyme in combination with a surfactant is taught in United States Patent No. 5,234,832 to Disch et al. which teaches the cleaning and sterilization of medical endoscopes, particularly heat and corrosion sensitive endoscopes made of flexible glass fiber, using a solution of surfactant, proteolytic enzyme and an aldehyde disinfectant. One problem with preparations such as taught by Disch et al. is that storage of liquid enzymes for prolonged periods, especially after dilution and unless refrigerated, can lead to inactivation of the enzyme which reduces or eliminates cleaning performance.

The use of disinfectant or sterilant concentrates in a powdered form has been taught in the prior art; for example, in U. S. Patent No. 5,350,563 to Kralovic et al.

The problem with the use of powders as disinfectant concentrates is that they also must be measured in order to prepare the diluted solution and must be poured from one container to another. In addition, there are sometimes problems with forcing the powder into solution.

Concentrated liquid cleaners have been found to be highly desirable by certain consumers. Important considerations in the selection of a cleaning composition include ease of handling, cleaning ability and stability of the product during storage.

One advantage of liquid cleaners is the ease of handling because liquids can be automatically pumped or dispensed directly to their final use application. Liquid cleaners can also be made into a highly concentrated intermediate aqueous solution which is subsequently flushed/diluted to its proper final use application solution.

Liquid cleaners are generally more rapidly soluble than powder or granule cleaners with the same or comparable active ingredients. Liquid cleaners can use higher levels of some surfactants that would cause powders or granules to cake if used at similar levels.

Almost all liquid cleaners have the disadvantage that they are diluted with water, so larger volumes and weights have to be shipped, stored and used to accomplish the equivalent cleaning as a highly concentrated powder or granules. Also, liquid cleaners cannot tolerate high concentration of organic surfactants with dissolved inorganic builders and sequestering agents with all the ingredients remaining homogenous throughout its shipping and storage. Many liquid cleaners utilize high concentrations of corrosive chemicals which easily spill or splatter on users causing chemical burns, inhalation burns, blindness or discomfort. Liquids can be corrosive to their dispensing equipment by virtue of the caustic alkali being incompatible with pump parts or delivery tubing. Additionally, the ingredients within liquids interact because the ingredient molecules are mobile. These interactions can precipitate or irreversibly inactivate some of the active ingredients upon storage.

Furthermore, liquids, for the most part, do not allow a stable, homogeneous solution

of surfactants, builders, sequestrants and oxygen bleach sources in a compatible stable product with long term storage stability.

One advantage of powder and granular cleaners is the high concentrations of active ingredients because few or no inert ingredients are required. In powder or granules cleaners, high levels of inorganic or organic salts can be used to raise alkalinity and soften water by chelating or sequestering water hardness ions. The powdered or granule cleaners can be used to provide oxidizing agents (bleaches) or reducing agents and granular enzyme materials which can be blended into free flowing powder or granule cleaners. The oxidizing or reducing agents and the enzymes are stable in the powdered or granulated cleaners with no significant loss of activity on extended storage. However, oxidizing agents mixed with caustic agents can prematurely decompose. This occurs because some caustic agents, specifically alkali metal hydroxides, are hygroscopic and the highly alkaline solution formed on the surface of the caustic agents reacts with the oxidizing agents.

A significant disadvantage of powder or granular cleaners for commercial applications is that they are not as accurately controllable in dispensing equipment as liquids. Powder or granular systems can require manually scooping a quantity of powder or granules for each use, thus not taking advantage of the ease, accuracy and hands-off labor savings of liquid dispensers. Also, powders and granules can cake if exposed to high humidity or temperatures. Once they become caked, they cannot be subsequently removed from their shipping container. Powders and granules can lose some of their activity if moistened or exposed to high humidity. Non-homogeneous powders and granules can segregate in their shipping containers, that is, separate or stratify by particle size or density resulting in a non-uniform mixture that may not be appropriate for ultimate use applications. Furthermore, powders and granules can create a safety hazard in that granules or airborne dust particles of irritating or corrosive materials can exit their container or otherwise come in direct contact with tissue, including lung tissue, causing burns or discomfort.

Other patents, for example, those of Hunt et al., U. S. Patent No. 4,265,847, and White et al., U. S. Patent No. 4,536,389, teach effervescent tablets useful for preparing solutions for sterilizing or disinfecting. Such compositions are rapid water soluble tablets typically comprising an active chemical compound, an alkali metal bicarbonate, e. g. sodium or potassium bicarbonate, and a solid aliphatic carboxylic acid such as citric acid, tartaric acid, adipic acid, or an acid salt thereof. In use, such tablets are dissolved in water whereupon the interaction of the bicarbonate and acid components results in the release of carbon dioxide, thus increasing the rate of solution of the other components and producing a solution in which the active (disinfecting) ingredient is homogenously dissolved. Methods for forming effervescent tablets are well known in the art. For example, see U. S. Patent No.

4,265,847 to Hunt et al. and U. S. Patent No. 5, 114,647 to Levesque et al., which disclosures are incorporated herein in their entireties, by reference.

Halogen compounds are effective as disinfecting agents but their use as such agents is limited due to difficulties in storage, mixing, and handling of concentrated halogens and instability of dilute forms. The use of sodium dichloroisocyanurate as a disinfecting agent is known in the prior art. For example, see U. S. Patent No.

4,536,389, to White et al., and U. S. Patent No. 5,114,642, to Levesque et al. Sodium dichloroisocyanurate hydrolyses in water to produce hypochlorous acid (HOCI) and hypochlorite (OC1-), which exist in solution at an equilibrium that is dependent upon the pH of the solution. For example, as shown in Figure 1, at neutral pH a solution consists of about 75% hypochlorous acid and 25% hypochlorite. The prior art teaches the use of bromide as a disinfectant, the hypobromous acid and hypobromite species are produced in solution typically by the use of bromo, chloro-5,5-dimethylhydantoin.

The hypohalous acid species is the antimicrobial form of the above compounds, with the hypohalite having some antimicrobial effect. However, the negative charge of the hypohalite inhibits its diffusion through the cell wall for microorganisms and thus lowers its antimicrobial effect.

United States Patent No. 4,252,664 to Inamorato, teaches a granular detergent composition with two types of granules, one type containing detergent and the other type containing effervescing agent and other ingredients, which may be a proteolytic enzyme. The composition is taught for use in clothes-washing machines. United States Patent No. 5,055,305 to Young teaches a denture cleansing tablet comprising a bleaching agent and an effervescing agent. United States Patent No. 3,962,107 to Levin et al. teaches a denture cleaning tablet comprising an enzyme and an effervescing agent.

Accordingly, there is a need for an effective disinfecting waste treatment agent packaged and supplied in a convenient effervescent form. The effervescent tablet must fully and rapidly dissolve in a rapid fashion to form a homogeneous disinfecting solution which is highly active and stable for a useful length of time, as well as produce a sizeable amount of effervescent foam. It has been heretofore unknown in art how to produce a waste treatment composition in tablet form that can dissolve rapidly and produce a sufficient amount of foam to aid in the waste treatment.

Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION The present invention comprises a water soluble effervescent tablet containing surfactant and enzymes which can be added directly to waste that is being treated. Thus, it is an object of the present invention to provide a cleaning product to be used for treating waste in holding tanks that is easier to use because it requires no measurement or pre-mixing, and that performs better and more reliably than current products.

The surfactants used in the invention are generally non-ionic, anionic, or amphoteric at concentrations sufficient to improve the wetting of the soils and consequently increase the contact between soil and enzyme.

The enzymes used are generally bacterial proteases from the genus Bacillus of the type used in other detergent applications but can also be from other microorganisms, such as from fungus, as for example Aspergillus or Saccharomyces, or may be plant

derived proteases such as papain, bromelin, or ficin, or animal derived proteases such as pancreatin, trypsin or pepsin.

The effervescing agents used in the present invention are generally sodium bicarbonate, sodium carbonate, and an acid, but may be other agents known in the art.

The tablet prepared from the surfactant, enzyme and effervescing agent and other optional ingredients, is of such a size and concentration to allow using whole tablets or multiple tablets directly in ultrasonic devices of different sizes and thus eliminating diluting, mixing and refrigerated storing of diluted liquids. The effervescence provides rapid solubility and mixing of the active ingredients.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an effervescent waste treatment composition in a tablet form and method of preparing the tablet. The waste treatment composition is contained in a single application atmospheric-resistant pouch. The single application pouches provide a convenient and compact, yet safe way to keep and store this waste treatment composition. To activate the waste treatment composition, the cleaner should be placed directly into the toilet bowl. Generally, single application pouches contain a pre-measured amount of cleaner to a pre-determined volume of a waste holding tank. The cleaner dissolves in the water in about 4 to 5 minutes, or another indication of dissolution is that the effervescence ceases. The effervescent foam level is sufficiently high to enhance the cleaning effectiveness of the tablet.

The waste treatment composition is carefully prepared, stored, and packaged to prevent moisture from initiating premature decomposition of the cleaning components rendering it less effective. The waste treatment composition is produced in a moisture-controlled atmosphere. This is done to inhibit the active ingredients from absorbing moisture from the air. Thus, the preparation and packaging of the waste treatment composition decreases the possibility of premature decomposition.

The waste treatment composition includes at least one enzyme, one surfactant, and an effervescent system. Additionally, at least one binder, lubricant, fragrance and odor blocker can be included in the waste treatment composition.

The proteolytic enzymes of the present invention are generally derived from, but not limited to, bacteria of the Bacillus species including B. subtilis, B. licheniformis and B. alkalophilis. Fungal enzymes derived from Aspergillus flavus or Aspergillus oryzae are also suitable as are the plant and animal enzymes papain, bromelin, ficin, pancreatin, trypsin and pepsin. These enzymes are available commercially from any of a number of enzyme suppliers at various levels of activity and degrees of purity. Some are also available as dedusted powders or in coated granulated forms for safe handling. The choice of enzyme is dependent upon the composition of the soils to be removed and the type of waste holding tank to be cleaned. The enzyme used in a preferred embodiment of the present invention is Deterzyme APUG-380TM, a partially granulated protease enzyme formulation manufactured by ENMEX, S. A. de C. V. of Mexico City, Mexico.

The enzyme Deterzyme in a preferred embodiment represents approximately 5-20% of the total weight of the tablet.

Other enzymes such as lipases or carbohydrases may also be included. Lipases are enzymes which break down lipids, or fats, which are often a component of the soil on the instrument to be cleaned. Thom, et al., United States Patent No. 5,133,893 teaches the combination of a detergent with a lipase. Carbohydrases are enzymes which break down carbohydrates, such as starch, into their component parts. Additionally enzymes derived from fungi Aspergillus niger and Trichoderma viride that breakdown cellulosic solid wastes and paper, such as cellulase, may be included in the waste treatment composition. In a preferred embodiment, cellulase represents approximately 5-20% by weight of the total weight of the tablet.

The surfactants used must be compatible with the enzymes used, should be low foaming and should be compressible low moisture powders suitable for use in effervescent tableting. The surfactant should make up from about 5% to about 20% of the tablet weight. Suitable nonionic surfactants are polyphenol, ethoxylates,

polyglycosides, polysorbate ethers, polyoxyethylene glycol ethers, alkyl polyglycosides, polysorbate ethers, polyoxyethylene ethers, and polyoxypropylene ethers. Suitable anionic surfactants are alcohol sulfates and alcohol ether sulfates. Amphoteric surfactants may be included as well.

In addition, the waste treatment composition is composed of an effervescent system. The effervescent system is composed of one or more of an alkali metal carbonate and an acid. One or more alkali metal carbonates may be selected from the following: sodium carbonate, sodium bicarbonate, and potassium carbonate. More particularly, sodium carbonate can be used as the alkali metal carbonate in 0-15% by weight, and sodium bicarbonate can be used in 10-40% by weight. Furthermore, one or more acids may be selected from the following: citric; maleic; fumeric; adipic; potassium or sodium phosphate, monobasic; oxalic; lactic; sulfamic; tataric acid; sodium bisulfite; and sodium or potassium pyrophosphate. In a preferred embodiment, citric acid is used as the acid in the range from 5-20% by weight of the tablet. The effervescent system, summation of the alkali metal carbonate and the acid, represents approximately 15-75% by weight of the total weight of the waste treatment composition.

In addition to the above ingredients, others anticipated include chelating or sequestering agents, enzyme stabilizers and activators, buffers, detergent builders, binders, colors, fragrances, odor inhibitors and fillers.

The lubricating agent limits sticking. The lubricant that may be used can be selected from, but not limited to, the following: sodium benzoate, stearates, mineral oil, silicates, or algenic acid. In a preferred embodiment, sodium benzoate is used as the lubricating agent. The lubricant represents 0-5% by weight of the total weight of the waste treatment composition.

In addition, the waste treatment composition may be composed of a binder.

The binder that may be used can be selected from, but is not limited to, the following: polyethylene glycol or sorbitol maltodextrin sugars (lactose, sucrose). In a preferred

embodiment, sorbitol is used as the binder. The binder represents 5-25% by weight of the total weight of the waste treatment composition.

Additionally, the waste treatment composition may contain an odor inhibitor or odor blocker. In a preferred embodiment, the odor blocker used is OrdenoneTM, available from Bel Air Fragrances, Mundelein, Illinois. The odor blocker represents 0-5% by weight of the total weight of the waste treatment composition.

Table 1 below lists the ingredients of the preferred embodiment of the invention, as well as the weight percent of each ingredient.

Table 1. Ingredients of the Preferred Embodiment Ingredient Weight Percent (%) Citric Acid (fine granualar) 5-20 Sodium Bicarbonate 10-40 Sorbitol 5-20 DeterzymeTM 5-20 Sodium Carbonate 0-15 Atlanta Fragrance #21544 0-5 FD&C Blue # 1 0-2 Cellulase 5-20 OrdenoneTM 0-5