Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials

Definitions

• the present invention relates generally to a new method of treating waste.
• the present invention relates to a method of treating articles of regulated wastes comprised of an acid polymer or a thermoplastic polymer and a contaminant by degrading and/or chemically treating the article.
• Waste disposal is an increasingly problematic concern for industrial facilities. Over the past 20 years, governments around the world have tightened environmental pollution regulations, resulting in stricter disposal requirements. Regulated wastes particularly have experienced tighter waste disposal regulations. The problem is magnified by the fact that ordinary wastes can become hazardous simply be coming into contact, and absorbing minimal amounts of regulated wastes. One particularly troublesome regulated waste is generated from industrial painting.
• Disposal costs generally depend on the level of the waste's hazard and the volume. The more hazardous the waste, the fewer available disposal sites and the more expensive the disposal cost. Likewise, for any waste, the bulkier the waste, the higher the disposal cost.
• the present invention relates to a method for treating wastes.
• One aspect of the present invention relates to a method of treating an article of regulated waste comprising the steps of: (a) providing an article comprising at least one acid polymer and at least one contaminant; (b) dissolving at least a portion of the article in a disposal liquid thereby creating a waste mixture comprising waste solids and the disposal liquid; and (c) treating the waste solids.
• Another aspect of the present invention relates to a method of treating an article of regulated waste comprising the steps of: (a) providing an article comprising at least one thermoplastic polymer and at least one contaminant; (b) dissolving at least a portion of the article in a disposal liquid (i) to introduce at least a portion of the contaminants into the disposal liquid and (ii) to create a waste mixture; (c) separating the disposal liquid from the waste mixture to obtain waste solids; and (d) treating the waste solids to render a non-regulated waste.
• Ranges may be expressed herein as from “about” one particular value, and/or to "about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
• X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.
• a weight percent of a component is based on the total weight of the formulation or composition in which the component is included.
• an effective amount of a compound or property as provided herein is meant such amount as is capable of performing the function of the compound or property for which an effective amount is expressed.
• the exact amount required will vary from process to process, depending on recognized variables such as the compounds employed and the processing conditions observed. Thus, it is not possible to specify an exact "effective amount.” However, an appropriate effective amount may be determined by one of ordinary skill in the art using only routine experimentation.
• Acid polymer means a polymer that forms a salt in a basic aqueous solution, such as aqueous solutions with a pH above about 7.0.
• Example acid polymers include, but are not limited to, ethylene acrylic acid polymers, ethylene methacrylic acid polymers, and derivatives, copolymers, and mixtures thereof. Acid polymers are not water soluble in neutral pH conditions at ambient temperatures but become soluble in water under suitable pH and temperature conditions.
• Bi-directional Shake Test means a test that measures the number of particles generated and released by a stressed equipment jacket. This test is based on American Standard Test Method F51.
• Biologically hazardous material means infectious material, potentially infectious material, and biologically active material such that an article contaminated with this material is rendered a regulated waste.
• biologically active material is a pharmaceutical agent.
• “Chemically treating” means contacting an article with a chemical other than water that chemically reacts with the article, or alters the charge characteristics of the article, as opposed to simply encapsulating the article.
• “Contaminants” within the context herein means any material that renders an article a regulated waste.
• Example contaminants include, but are not limited to, oil, paint, hydrocarbons, biologically active materials, infectious material, potentially infectious material, and radioactive material.
• “Degrade” means to lessen the structural integrity and, to subdivide the material into a greater number of parts. Thus, the degradation can occur by shredding (i.e. cutting, grinding, or chopping), crushing, or at a molecular level by dispersing or dissolving the material.
• the dispersion can be only partial, but the article will still be considered to have been dispersed within the meaning of this document.
• less than half (by weight) of the material may be dispersed or dissolved in solution. The remainder is broken into pieces that can be retrieved. Degradation preferably facilitates the eventual treatment of the material's hazardous characteristics, and preferably occurs in a disposal liquid.
• Degradable polymer means a polymer that undergoes a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties.
• Example degradable polymers include hydrolytically degradable polymers such as polylactic acid, polyesteramides, polyglycolic acid, polyhydroxy butyrate-co-valorate and the like, and combinations thereof as copolymers, blends, mixtures, and the like.
• Disperse means that upon contact with a fluid under appropriate conditions, the material disperses partially or completely into the fluid to form a dispersion.
• Dissolve means that upon contact with a fluid under appropriate conditions, the weight of solid material is reduced by partial or complete dissolution of the material into solution.
• the material preferably fragments or breaks apart structurally, if it does not dissolve or disperse completely.
• Halzardous describes a solid waste, or combination of a solid and liquid waste, which because of its quantity, concentration, or physical, chemical, or infectious characteristics:
• (a) may cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness;
• (b) may pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed; or
• (c) has been defined as a hazardous substance in 42 U.S.C. 9601 or by the Administrator of the Environmental Protection Agency.
• articles of regulated waste include infectious waste generated at hospitals (i.e. articles that have come into contact with bodily fluids), and industrial waste that must typically be managed as a "hazardous substance" under 42 U.S.C. 9601, such as articles contaminated by paint.
• NDP stands for novel degradable polymer and when used in this specification refers to an ethylene-(meth)acrylic acid copolymer.
• "Ethylene-(meth)acrylic acid copolymer” in turn, means a copolymer of ethylene and acrylic acid, a copolymer of ethylene and methacrylic acid, a mixture of copolymers of acrylic and methacrylic acids or terpoiymers of acrylic acid, methacrylic acid and ethylene.
• the ethylene-(meth)acrylic acid copolymer preferably comprises 10-30 wt.% acid residues, more preferably 15-25 wt.%.
• the NDP may be present as an acid polymer.
• the term "ionomer” means a copolymer of ethylene and (meth)acrylic acid, wherein the copolymer has been neutralized with a metal cation.
• Ethylene- (meth)acrylic acid ionomers are typically obtained by partially reacting an ethylene-(meth)acrylic acid copolymer with a metallic salt to form ionic crosslinks between the (meth)acrylic acid moiety residues within a copolymer chain or between neighboring chains. The cationic charge of the metallic salt partially neutralizes the acid residues of the copolymer.
• Suitable cations for neutralizing the acidic moieties are Na + , K + , Li + , Cs + , Rb + , Hg + , Cu + , Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Cu 2+ , Cd 2+ , Hg 2+ , Sn 2+ , Pb 2+ , Fe 2+ , Co 2+ , Ni 2+ , Zn 2+ , Al 3+ , Sc 3+ , Fe 3+ and Y 3+ .
• Preferred cations include sodium, lithium and potassium ions.
• the NDP may also be present as a blend of ionomer and ethylene-
• (meth)acrylic acid copolymer The blend of ionomer and ethylene- (meth)acrylic acid copolymer can be present at various ratios, including less than or greater than 9:l, 8:l, 7:l, 6:l, 5:l, 4:l, 3:1, 2:1, 1 :1, 1 :2, 1 :3, 1 :4, 1 :5, 1 :6, 1 :7, 1 :8, and 1:9.
• NDP is disclosed in U.S. Application Serial Nos. 08/923,698 and
• NDP Treatable FilmTM commercially available from Isolyser Company, Inc., Norcross, Georgia.
• Optional or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
• the phrase "optionally substituted lower alkyl” means that the lower alkyl group may or may not be substituted and that the description includes both unsubstituted lower alkyl and lower alkyl where there is substitution.
• “Potentially infectious” means including, but not limited to, blood and body fluids and materials or articles contaminated with blood or body fluids that are typically considered to be infectious.
• Radioactive means a material or article contaminated with radioactive isotopes.
• Regular Waste includes (1) hazardous; (2) potentially infectious; and (3) radioactive wastes.
• a "non-regulated waste” is a waste that is not considered a regulated waste as disclosed herein.
• Readily Releasable Particles means particles that exist on the surface of a cover or jacket and can be removed without the application of mechanical energy. This test is based on American Standard Test Method F51. "Particle” means a solid or liquid object generally between 0.001 and 1000 ⁇ m in size. The most common particle is lint.” Surface Resistivity” means resistance measured in ohms/square at 73 °F and 50% relative humidity.
• thermoplastic polymer materials means thermoplastic polymers, thermoset polymers, solvent castable polymers, natural polymers, and derivatives and copolymers of these polymers. These materials may be manufactured into panels of knitted fabrics, woven fabrics, non- woven fabrics, films, and molded panels using any available manufacturing method including, but not limited to: single knit, double knit, interlock knit, warped knit, crocheted knit, air laid, dry laid, wet laid, hydroentangled, thermo bonded, chemical bonded, blown extrusion, cast extrusion, hot melt processing, blow molding or injection molding. These thermoplastic polymer materials may be composites or a single layer.
• Water soluble means that the polymer will completely dissolve upon extended contact with water.
• Nonlimiting examples of water soluble polymers include polyvinyl alcohol, poly aspartic acid, polyacrylic acid, polymethacrylic acid, polyacrylamid, polyvinyl pyrrolidone, polyalkylene oxides, complex carbohydrates, and derivatives, copolymers and mixtures thereof.
• Articles of regulated waste can be present in many forms, and include knitted fabrics, woven fabrics, non-woven fabrics, films, and molded parts of polymers configured using any available manufacturing method including, but not limited to: single knit, double knit, interlock knit, warped knit, crocheted knit, air laid, dry laid, wet laid, hydroentangled, thermo bonded, chemical bonded, blown extrusion, cast extrusion, hot melt processing, blow molding or injection molding. Polymeric materials may be composites or a single layer.
• Other articles of regulated waste may include, but are not limited to, surgical drapes and gowns, woven sponges and towels, personal protective garments, wipes, collection devices (such as suction canisters), and equipment covers.
• the article of regulated waste preferably comprises an acid polymer, a thermoplastic polymer, natural fabric or fiber, or any combination of these materials.
• One preferred class of articles comprises acid polymers alone or in combination with water soluble polymers, degradable polymers and/or dispersable polymers.
• polymeric materials examples include polylactic acid, polyethylene, polypropylene, ethylene vinyl acetate, polybutylene, polyolefm, polyester, polyurethane, polyacrylate, polymethacrylate, polyvinyl chloride, polyvinyl acetate, cellophane, polyvinyl alcohol, and NDP, and blends of these materials.
• Polyvinyl alcohol and NDP are preferred polymeric materials.
• Particularly suitable natural fabric or fiber includes cotton, wool, leather, and silk, and blends of these materials.
• the article can be present as a film, a shaped and molded article, or as a fibrous fabric.
• the article can be absorbent, and can, for example, be used as an industrial wipe to manage spills of hazardous materials, or to otherwise wipe up hazardous liquids.
• the article can be a fabric, a plurality of non- fabric fibers, or granular material when used for such absorption.
• the material can also be a filter used to trap fluid-borne contaminants from liquid or gas streams.
• cover, and jackets that can be employed in the present invention, are those articles that sustain a low release of particles.
• low release it is meant that the jacket is functional as an equipment jacket in a desired low particle environment. This can be measured in a variety of manners.
• one preferred embodiment of the invention relates to an article with less than 500,000 readily releasable particles per square meter of equipment jacket, more preferably less than 100,000 readily releasable particles per square meter.
• Another preferred embodiment of the method of disposal of the present invention uses an article with less than 2.5 million particles per square meter of equipment jacket as measured with the bi-directional shake test, more preferably less than 200,000 particles per square meter.
• a further embodiment uses an article devoid of particles that are readily visible to the naked eye.
• the above-described low release of particles may result with or without anti-particle treatment. Suitable anti-particle treatments include laundering and application of surface coating agents.
• a preferred embodiment of the invention provides a method of disposal of an article that has anti-static properties and/or comprises an antistatic agent.
• Example antistatic agents include amines, glycerol esters, quaternary ammonium compounds, anionics, alkane sulfonates, and the like as disclosed in Modern Plastics, Mid-November 1998 issue, pages C47- C51 , which is incorporated in this application in its entirety.
• the article may have anti-static properties.
• One indication of anti-static properties is surface resistivity.
• a suitable surface resistivity is based on the particular industrial application in which the article is employed. For example, the NFPA (National Fire Protection Agency) standard for surface resistivity is 1 x 10 11 ohms/square. Where anti-static properties are an issue, it can often be desirable to meet this standard.
• the article(s) may be comprised of a monolithic film of thermoplastic polymer material. Alternatively, the articles may be comprised of additional layers, such as a reinforcing layer.
• the thermoplastic polymer panel(s) may have any thickness such that it has sufficient strength to withstand the required use.
• One preferred embodiment has a thermoplastic polymer panel(s) thickness of about 0.01 mm to about 0.6 mm. More preferably, the thickness is about 0.02 mm to about 0.2 mm, with the range of about 0.03 mm to about 0.6 mm as the most desirable thickness, most preferably 0.06 mm.
• Similar articles can be used in medical applications where they can become contaminated with blood and body fluids, which may be potentially infectious. Treatment of these articles may include disinfection (signifying a 10 6 reduction in vegetative microorganisms in an aqueous solution at temperatures above 90 °C) or sterilization (defined as 10 6 reduction in
• Bacillus spores in an aqueous solution at temperatures above 118 °C for time intervals appropriate to the level of treatment.
• These same articles may also be contaminated with radioactive waste. Degradation of these articles will release the radioactive contamination into an aqueous solution which may be held for half life degradation or filtering. The resulting aqueous solution can be safely discharged.
• the article may comprise paint, a liquid hydrocarbon, oil, ink, or combinations of these substances.
• the article comprises a polymeric material, natural fabric or fiber, and further comprises paint, a liquid hydrocarbon, oil, ink, or combinations of these substances, that have been splattered on or absorbed by the article.
• a step of the process involves treating the article so as to dissolve and/or degrade a portion of the article.
• Degradation can occur by any of the methods discussed above.
• the degradation occurs while contacting the article with a disposal liquid at temperatures above about 37 °C, 40 °C, 45 °C, 50°C, 55 °C, 60°C, 65°C, 70°C,75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, with temperatures above 90°C particularly preferred.
• Such high temperature treatment has two potential benefits: (1) many materials dissolve or disperse in hot liquid (such as polyvinyl alcohol and NDP), and dissolve or disperse better at hotter temperatures; and (2) higher temperatures can disinfect the article and render it nonhazardous. Higher temperatures are thus desirable whenever disinfection is desired, regardless of the method of degradation.
• the high temperature treatment can occur separately from any other step of the process, or alternatively the article can be degraded, and/or chemically treated during or by the high temperature treatment.
• the degradation occurs while contacting the article with a disposal liquid of pH greater than about 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0, where a pH greater than 10.0 is especially preferred.
• a disposal liquid of pH greater than about 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0, where a pH greater than 10.0 is especially preferred.
• Such high pH treatments are especially preferred when degrading articles comprising acid polymers that degrade best at higher pH levels.
• the article comprises NDP, and is degraded at elevated pH levels and temperatures. Any combination of temperature and pH can be employed in the inventive process. These processes can include pH and temperature combinations which are consistent with commercial and traditional laundering, e.g., on the order of 70°F and pH on the order of 9.5 to 12.0. In addition, combinations of
• the disposal liquid acts as a heat and/or chemical transfer medium.
• any suitable disposal liquid may be used.
• Example disposal liquids include, but are not limited to, water.
• the disposal liquid may include additional components that act as processing aid, such as, but not limited to, surfactants, acids, bases, and coagulants.
• the article is degraded by shredding and dispersing and/or dissolving the article, either simultaneously or consecutively.
• degradation can be enhanced by shredding the article before or during the pH and temperature treatment.
• the process of the present invention includes the dissolution of at least a portion of the article in the disposal liquid so as to form a waste mixture comprising waste solids and the disposal liquid which preferably includes at least a portion of the contaminants.
• the waste mixture containing degraded waste solids and the disposal liquid can be further processed after dissolution by suitable treatment.
• the waste solids can be treated by processes such as chemical treatment, disinfection, and deactivation of biologically active materials.
• Chemical treatment can occur by many methods known to workers skilled in the art. For example, a paint contaminated article that has been sufficiently degraded can be chemically treated. Chemical treatment can also occur by contacting the article with a basic solution. The higher pH can disinfect the article or render it nonhazardous. For example, a high pH detackifies paint and renders articles contaminated by paint less hazardous.
• the high pH treatment can thus function as chemical treatment apart from the degradation step, or alternatively the article can be degraded and chemically treated in the high pH.
• Disinfection and/or deactivation of biologically active materials may include denaturing proteins.
• This process may be performed by any suitable method including, but not limited to, heat or an antimicrobial agent. Any suitable antimicrobial/antifungal agent may be used, such as chlorohexidine glucanate, iodophores, pyrithiones, isothiazolines, or benzimidazoles. These agents may be present in any effective amount.
• Treatment can preferably involve separating the waste solids from the disposal liquid. The waste solids can then be disposed or further processed, and the disposal liquid discharged with other waste water. Depending on the size and nature of the waste solids, a number of separation techniques may be used, including filtering and skimming. The separated waste solids can then be dewatered and treated.
• the article may be appropriate to further treat the waste solids to facilitate its separation from the disposal liquid.
• acid can be used to precipitate the NDP out of solution.
• the pH of the solution is lowered to 8.5 or below by adding an acid such as sulfuric acid.
• the precipitated solids can be coagulated with a coagulant such as alum to even further facilitate separation.
• coagulants include, but are not limited to, aluminum and ferric compounds and organic macromolecules known as polyelectrolytes (or polymers).
• a proper dosage of the right polyelectrolyte can improve finished water quality while significantly reducing sludge volume and overall operation costs.
• Suitable coagulating and flocculating agents are described in "Everything you want to know about Coagulation & Flocculation,” Zeta-Meter, Inc., 1993, which is incorporated herein by reference in its entirety.
• the invention provides a number of ways that regulated waste streams can be managed. By degrading hazardous articles into smaller pieces, one is able to better treat the article chemically. Treatment of articles contaminated with paint is a good example. Although presented as an example of the invention, it should in no way limit the scope of the invention.
• dissolution of a paint contaminated article gives waste paint solids in a disposal liquid.
• complete dissolution of the contaminated article is not necessary to employ these treatment methods.
• These treatment methods can also be employed if the article is degraded into pieces or particles which, because of their reduced size, can be treated by similar methods.
• the waste mixture is treated to separate the waste paint solids which are then introduced to a paint sludge pit and managed along with the paint sludge from a paint booth.
• the article and/or any dissolved or dispersed waste solids are recovered from the disposal liquid, and the liquid discharged to an on-site waste water treatment process.
• the degradation of the contaminated article can also facilitate further processing of the waste other than by chemical treatment.
• the waste can be subsequently processed by shredding, compacting or crushing.
• the material that is obtained is greatly reduced in volume, and is more readily disposed.
• one or more of the articles in a waste stream is degraded by dissolution or dispersion, and reclaimed.
• the reclaimed articles and/or solids can then be further processed by shredding, compacting or crushing (or otherwise reduced in volume) before disposal.
• valuable articles will remain intact after the initial degradation step. When such articles are present they can be recovered, and reused, before the rest of the waste stream is further processed before disposal.
• This method has particular application to medical waste, which can be disinfected during either the degradation or shredding.
• the method is used to treat articles collected in a bag, in which only some of the articles are degradable, or the articles do not fully dissolve or disperse when degraded.
• the contents of the bag can be processed by first subjecting the bag and its contents to degradation conditions (and optionally disinfection or chemical treatment). Any contents that do not degrade, or which only partially degrade, can be reclaimed after the degradation step, and either segregated for reuse, or further processed by shredding, compacting or crushing.
• the degradable bag and its contents can be placed into a mesh bag or basket that does not degrade. Alternatively, the degradable articles can be placed directly into the mesh bag or basket.
• Example 1 A 1.5 gram sample of NDP film was covered with a solvent-based primer paint. The film was immersed in a 0.2 -0.5 wt% NaOH solution (5 wt.% NDP, 95 wt.% NaOH solution) at 95 °C and agitated. A suspended solution was obtained from this procedure. The pH of the suspended solution was about 12.0 units. The biochemical oxygen demand (“BOD”), chemical oxygen demand (“COD”) and total suspended solids (“TSS”) were measured and the results are recorded as the "suspended solution" sample in table 1.
• BOD biochemical oxygen demand
• COD chemical oxygen demand
• TSS total suspended solids
• Example 2 A 1.5 gram sample of NDP film was covered with a water-based color paint and treated as described in example 1. The sample did not settle as quickly or filter as easily as in example 1, but a clear supernatant was still obtained. The results for BOD, COD and TSS for the suspended solution and the supernatant are included in table 2. The TCLP results indicated that the settled solids were below regulatory limits for metals, volatiles and semi- volatiles, thus making the solids a non-regulated waste.
• Example 3 A 1.5 gram sample of NDP film was covered with a solvent-based clear paint and treated as described in example 1. The sample quickly settled and filtered easily, but the supernatant was cloudy. The results for BOD, COD and TSS for the suspended solution and the supernatant are included in table 3. The TCLP results indicated that the settled solids were below regulatory limits for metals, volatiles and semi-volatiles, thus making the solids a non-regulated waste. Table 3 : Clear Paint- solvent based

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  • 2000-07-28 EP EP00950829A patent/EP1214157A1/de not_active Withdrawn
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