Cleaning and separating medical waste

Abstract

The present invention comprises a method of shredding treated medical waste, cleaning it of all traces of biological gunk, and sorting it into separate components for recycling. To clean biological gunk from materials, all materials must be first shredded into small parts to expose the interior. The cleaning is performed by submerging the gunk coated materials into a caustic solution that breaks down and dissolves the gunk off of the materials. The caustic solution may comprise sodium hydroxide, potassium hydroxide, or a similar chemical, which is highly effective in producing a corrosive chemical that can break down blood, bone marrow, urine, unused medication, food waste, organs, tissues and any other biologic materials. After all of the biological material is removed from the cleaned materials, they are sorted into component materials, such as plastics, metals, rubbers, glass, etc.

Claims

1. A method of cleaning and separating treated medical waste into component materials for recycling, the method comprising: first receiving material feed; second reducing the size of the material feed; third washing the material with a caustic solution comprising of potassium hydroxide to remove biologic contamination, wherein the caustic solution has a pH of about 11 pH to 12.5 pH and a temperature of about 120 degrees F. to 140 degrees F.; fourth separating the washed material into a primary top fraction group comprising polypropylene, polyethylene, labels, polystyrene, fibers, rubbers, gloves, nylon, acrylonitrile butadiene styrene (ABS), and textiles; a primary bottom fraction group comprising glass and metals; fifth performing a density separation to separate the primary top fraction group into a secondary top fraction group comprising polypropylene, polyethylene, labels, and polystyrene, and a secondary bottom fraction group comprising fibers, rubber, plastics selected from the group consisting of nylon, ABS, and gloves, and textiles; sixth rinsing the materials in the secondary top fraction group, the secondary bottom fraction group, and the primary bottom fraction group; seventh drying the materials in the primary bottom fraction group; eight storing the materials in the secondary top fraction group, the secondary bottom fraction group, and the primary bottom fraction group in feeder bins; ninth drying the materials in the secondary top fraction group and the secondary bottom fraction group; tenth separating the materials in the secondary top fraction group and the secondary bottom fraction group with air classification; eleventh separating out ferrous metal material from the secondary top fraction group, the secondary bottom fraction group, and the primary bottom fraction group using magnets; twelfth separating out nonferrous metal material from the secondary top fraction group, the secondary bottom fraction group, and the primary bottom fraction group using eddy currents; and thirteenth separating out the remaining materials in the secondary top fraction, secondary bottom fraction, and primary bottom fraction groups into polypropylene, polyethylene, rubber, glass, nylon, and ABS.

2. The method of claim 1, wherein the remaining materials are separated out using near-infrared sorting.

3. The method of claim 1, wherein the remaining materials are separated out using density separation.

4. A method of cleaning and separating treated medical waste into component materials for recycling, the method comprising: first receiving material feed; second reducing the size of the material feed; third washing the material with a caustic solution comprising of potassium hydroxide to remove biologic contamination, wherein the caustic solution has a pH of about 11 pH to 12.5 pH and a temperature of about 120 degrees F. to 140 degrees F.; fourth separating the washed material into a top fraction group comprising polypropylene, polyethylene, labels, polystyrene, fibers, rubbers, gloves, nylon, ABS, and textiles; fifth separating the washed material into a primary bottom fraction group comprising glass and metals; sixth drying the materials in the primary bottom fraction group; seventh separating out ferrous metal material from the primary bottom fraction group using magnets; eight separating out nonferrous metal material from the primary bottom fraction group using eddy currents ninth using a hot sink float tank to separate the top fraction group into a primary top fraction group comprising polypropylene, polyethylene, labels, and polystyrene, and a secondary bottom fraction group comprising fibers, rubber, plastics, gloves, nylon, ABS, and textiles; tenth rinsing the materials in the primary top fraction group and the secondary bottom fraction group; eleventh drying the materials in the primary top fraction group and the secondary bottom fraction group; twelfth using air classification to separate waste from the materials in the primary top fraction group and the secondary bottom fraction group; thirteenth separating the remaining materials in the primary top fraction group into polypropylene and high density polyethylene; and fourteenth using density separation to separate the materials in the secondary bottom fraction group into plastics, nylon, ABS, and rubber.

5. The method of claim 4, wherein the remaining materials are separated out using density separation.

6. A method of cleaning and separating treated medical waste into component materials for recycling, the method comprising: first receiving material feed; second reducing the size of the material feed; third washing the material with a caustic solution comprising of potassium hydroxide to remove biologic contamination wherein the caustic solution has a pH of about 11 pH to 12.5 pH and a temperature of about 120 degrees F. to 140 degrees F.; fourth separating the washed material into a primary top fraction group comprising polypropylene, polyethylene, plastics, labels, polystyrene, fibers, rubber, gloves, nylon, ABS, and textiles; fifth separating the washed material into a primary bottom fraction group comprising glass and metals; sixth rinsing the materials in the primary top fraction group and the primary bottom fraction group; seventh drying the materials in the primary top fraction group and the primary bottom fraction group; eight separating the materials in the primary top fraction group with air classification; ninth separating the materials in the primary top fraction group with magnets; tenth separating the remaining materials in the primary top fraction group into polypropylene, polyethylene, polystyrene, plastics, nylon, ABS, and rubber; eleventh separating the materials in the primary bottom fraction group with additional magnets; and twelfth separating out nonferrous metal material from the primary bottom fraction group using eddy currents.

7. The method of claim 6, wherein the remaining materials are separated out using near infrared sorting.

8. The method of claim 6, wherein the remaining materials are separated out using density separation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.

(2) FIG. 1 is a flowchart of a method in which at least one of the embodiments of this invention is implemented.

(3) FIG. 2 is a flowchart of the first part of a method in which at least one of the embodiments of this invention is implemented.

(4) FIG. 3 is a flowchart of the second part of a method in which at least one of the embodiments of this invention is implemented.

(5) FIG. 4 is a fraction diagram of a method in which at least one of the embodiments of this invention is implemented.

(6) FIG. 5 is an alternative embodiment of a fraction diagram of a method in which at least one of the embodiments of this invention is implemented.

(7) FIG. 6 is an alternative embodiment of a flowchart of the first part of a method in which at least one of the embodiments of this invention is implemented.

(8) FIG. 7 is an alternative embodiment of a flowchart of the second part of a method in which at least one of the embodiments of this invention is implemented.

(9) FIG. 8 is another alternative embodiment of a flowchart of a method in which at least one of the embodiments of this invention is implemented.

DETAILED DESCRIPTION OF THE INVENTION

(10) It is to be understood that this invention is not limited to any particular embodiment described, which may vary. Also, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of this invention will be limited only by the appended claims.

(11) In the following detailed description, numerous specific details are set forth in order to explain and provide a thorough understanding of the present invention. However, it is apparent that the present invention may be practiced without all of these specific details. Thus, all illustrations of the drawings are for the purpose of describing versions of the present invention, and are not intended to limit the scope of the invention.

(12) In the following section, the present invention is described fully by referencing the details in the enclosed drawings, which illustrate certain embodiments of the invention. The numbers shown in this specification refer to the corresponding numbers in the enclosed drawings. The terminology used is to describe the particular embodiment shown and is not intended to limit the scope of the invention. The invention may also be embodied in many other forms in addition to the embodiments shown. Thus, the embodiments shown should not be construed as limiting, but rather, to allow a thorough and complete description of the disclosure that conveys the scope of the invention to a person having ordinary skill in the art in the field of this invention. Therefore, for the terms used herein, the singular forms “the,” “a,” and “an” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. The term “and” includes any and all combinations of one or more of the associated listed items. As used herein, the terms “comprising” and “comprises” when used in this specification, identify specific steps, integers, operations, features, components, and elements, but do not preclude the presence or addition of one or more other steps, operations, features, components, and elements. In addition, the features, components, and elements referenced may be exaggerated for clarity.

(13) Unless otherwise defined, all scientific terms, technical terms, or other terms used herein have the same meaning as the term that is understood by one having ordinary skill in the art in the field of this invention. It is also understood that these terms, including their dictionary meaning, should be understood as having the meaning, which is consistent with their definitions in the related relevant art. In addition, the present disclosure is not to be interpreted in an idealized or overly formal sense unless expressly stated so herein. Constructions or functions that are well known in the art may not be fully described in detail for brevity.

(14) In describing the invention, it is understood that a number of steps and methods may be disclosed. Each of these may have individual benefit. Also, each may be used in conjunction with at least one or more of the disclosed steps and methods. Therefore, this description will refrain from stating each and every possible combination of the individual steps and methods for the sake of brevity. Regardless, the specification and related claims should be understood with the combinations that are entirely within the scope of the claims and inventions.

(15) The disclosure in this invention are examples of how it may be implemented and are not intended to limit the scope of the invention to the specific embodiments shown in the accompanying drawings or the description provided herein. The present invention will now be described by example in the following paragraphs by referencing the accompanying drawings, which represent embodiments and alternative embodiments.

(16) With reference to FIG. 1, a method of separating and cleaning treated medical waste is described to separate it into its component materials for recycling. The method comprises first receiving treated medical waste, which is known as “Material Feed” 110. Although the Material Feed 110 is noninfectious, it may still be coated with traces of biological gunk, which may include blood, bone marrow, urine, unused medication, food waste, organs, tissues, or other biologic materials.

(17) Next, the Material Feed 110 is reduced in size by shredding it into small parts to expose its interior, in a process known as “Size Reduction” 120. After that, the Material Feed is washed to remove biologic contamination, in a step called “Washing” 130. Specifically, Washing 130 is performed by submerging the gunk coated materials into a caustic solution that may comprise sodium hydroxide, potassium hydroxide, or a similar chemical. This caustic solution is highly effective in producing a corrosive chemical that can break down and dissolve gunk off of the materials. The potential of hydrogen (“pH”) level for the caustic solution may preferably be in the range of 11 pH to 12.5 pH, and the temperature of the caustic solution may preferably be in the range of between 120 degrees Fahrenheit (“F”) to 140 degrees F.

(18) Next, the materials are dried, in a step called “Drying” 140. After that, the resulting material is separated out using air in a step called “Air Classification” 150. Air Classification 150 is a method of using air pressure to separate light fluffy material, such as gloves, labels, and textiles, from denser materials, such as plastic, glass, and metal.

(19) Next, ferrous metal materials are separated out with magnets, in a step called “Magnets” 160. After that, nonferrous metal materials are separated out with eddy currents in a step called “Eddy Currents” 170. Eddy Currents 170 is a method of extracting nonferrous (nonmagnetic) metals by producing an electromagnetic field that opposes metallic objects. As nonferrous metals pass over the magnetic field, they are pushed out of and ejected from the other materials.

(20) Next, materials are separated based on their density into segregated plastics, rubber, and glass, by Density Separation and/or Near-Infrared Sorting 180. Density Separation is a term used to describe separating materials according to their specific gravity, which is the ratio of the density of a substance to the density of a reference substance. The most common method is to utilize water, which has a specific gravity of approximately 1.0. Its density may be increased by adding salt or decreased by adding isopropyl alcohol. By modifying the density of the liquid, materials with a lower density than the liquid will float while materials with a higher density will sink. By modifying the liquid density, various material separations may be conducted. Similar Density Separation can also be conducted with hydrocyclones, air and other methods. Near-Infrared (“NIR”) Sorting, also known as NIR Spectroscopy, involves using the wavelength for different material chemistries of mixed plastics to sort colored resins composed of different polymers. Diffuse reflection measurements are made in the NIR region to capture distinct spectral differences resulting from the unique polymer compositions, while avoiding the detection of spectral differences arising from resin color.

(21) FIG. 2 is a flowchart of a method of separating and cleaning treated medical waste to separate it into its component materials for recycling. The method comprises first receiving the Material Feed 110 as described above. Next, Size Reduction 120 reduces the Material Feed 110 in size by shredding it into small parts to expose the interior. The Material Feed 110 then under goes Washing 130 in a sink/float tank with a caustic solution to remove the biologic contamination. The pH level for the caustic solution may preferably be in the range of 11 pH to 12.5 pH, and the temperature of the caustic solution may preferably be in the range of between 120 degrees F. to 140 degrees F.

(22) After that, the washed materials are separated into a Primary Top Fraction group 200 and a Primary Bottom Fraction group 300. The Primary Top Fraction group 200 consists of polypropylene, polyethylene, labels, Styrofoam, fibers, and rubber. Styrofoam is a registered trademark of Dow Chemical Company for a closed-cell extruded polystyrene foam. The Primary Bottom Fraction group 300 consists of glass and metals, such as steel, stainless steel, and titanium.

(23) Next, Density Separation 210 is performed on the Primary Top Fraction group 200 to further separate the materials into a Secondary Top Fraction group 220 and a Secondary Bottom Fraction group 240. The Secondary Top Fraction group 220 consists of polypropylene, polyethylene (high density and low density), labels, and Styrofoam. The Secondary Bottom Fraction group 240 consists of fibers, rubber, heavy plastics, gloves, nylon, Acrylonitrile Butadiene Styrene (“ABS”), textiles, and trash.

(24) The Secondary Top Fraction 220 materials are then rinsed, in a step called Rinse 225, and then stored in a feeder bin 230. Similarly, the Secondary Bottom Fraction 240 materials are rinsed, in a step called Rinse 245, and stored in a feeder bin 250. The Primary Bottom Fraction materials 300 are also rinsed (Rinse 310), dried (Drying 320), and placed in feeder bins 330 for storage.

(25) Next, as shown in FIG. 3, the Secondary Top Fraction 220 and the Secondary Bottom Fraction 240 groups are dried (Drying 140). After that, these materials are separated with Air Classification 150 to separate out the light fluffy waste materials, such as labels, low density polyethylene, Styrofoam, gloves, fibers, and textiles, which leaves the denser materials, such as heavier plastics, glass, and metal. Next, ferrous metal waste are separated out from these materials using Magnets 160. After that, nonferrous metal waste in these materials are separated out with Eddy Currents 170. Similarly, as shown in FIG. 3, the ferrous metal waste in the Primary Bottom Fraction materials 300 materials are separated out with Magnets 160, and the nonferrous metal waste are separated out with Eddy Currents 170.

(26) The next step involves using density and/or electrostatic separation 400 to separate the materials into separate groups of polypropylene 410 or high density polyethylene 420. Also, segregated plastics, such as polypropylene, polyethylene, nylon, ABS and other heavy plastics are separated with Density Separation 430. Density Separation 450 is also used to separate out rubber 460. In addition, glass 470 is separated out.

(27) With reference to FIG. 4, further details are explained regarding the various stages of separation. The first stage involves separating the unprocessed bulk material, known as Material Feed 110. During the first stage, the Material Feed 110 is separated into a Primary Top Fraction group 200, which comprises polypropylene, polyethylene, rubber, gloves, nylon, ABS, other plastics, textiles, and trash; and a Primary Bottom Fraction group 300, which comprises glass and metal.

(28) The Primary Top Fraction group 200 is further separated into a Secondary Top Fraction group 220, which comprises polypropylene, polyethylene, PE labels, some gloves, and textiles, and a Secondary Bottom Fraction group 240 or “Middle Fraction,” which is comprised of rubber, gloves, nylons, ABS, other plastics, textiles, and trash.

(29) Next, the Secondary Top Fraction group 220 is divided into polypropylene 410; polyethylene (regrind) 420; and PE labels, gloves, textiles, and waste 480. The Secondary Bottom Fraction group 240 is divided into PE labels, gloves, textiles, and waste 480; nylon, ABS, and other plastics 440; and rubber 460. Finally, the Primary Bottom Fraction group 300 is separated into steel 485, stainless steel 490, titanium 495, and glass 470.

(30) In at least one alternative embodiment, as shown in FIG. 5, an optional method with less steps is shown for reducing the number of stages of separation. The first stage still involves separating the Material Feed 110 into a Primary Top Fraction group 200 and a Primary Bottom Fraction group 300. The Primary Top Fraction group 200 is then directly separated into polypropylene 410; polyethylene 420; labels, gloves, textiles, and waste 480; nylon, ABS, and other plastics 440; and rubber 460. The Primary Bottom Fraction group 300 is still directly separated into steel 485, stainless steel 490, titanium 495, and glass 470.

(31) With reference to FIG. 6, an alternative method of separating and cleaning treated medical waste is described to separate it into its component materials for recycling. The method comprises first receiving Material Feed 110. Next, the Material Feed 110 under goes Size Reduction 120 by shredding it into small parts to expose the interior. The Material Feed 110 is then washed in a caustic solution in a hot sink/float tank to remove the biologic contamination in a step called Washing 130. Washing 130 is performed by submerging the gunk coated materials into a caustic solution that may comprise sodium hydroxide, potassium hydroxide, or a similar chemical. This caustic solution Washing 130 is highly effective in producing a corrosive chemical that can break down and dissolve gunk off of the materials. The pH level for the caustic solution may preferably be in the range of 11 pH to 12.5 pH, and the temperature of the caustic solution may preferably be in the range of between 120 degrees F. to 140 degrees F.

(32) Next, the washed materials are separated into a Top Fraction group 200 that comprises polypropylene, polyethylene, labels, Styrofoam, fibers, and rubbers; and a Primary Bottom Fraction group 300 that comprises glass and metals, such as steel, stainless steel, and titanium. After that, a hot sink/float tank 500 is used to separate the Top Fraction group 200 into a Primary Top Fraction group 220 which comprises polypropylene, polyethylene (high density and low density), labels, and Styrofoam; and a Secondary Bottom Fraction group 240, which comprises fibers, rubber, heavy plastics, gloves, nylon, ABS, textiles, and trash.

(33) FIG. 6 at point “E” continues to point “E” on FIG. 7 to a step entitled Rinse 225, which involves rinsing the Primary Top Fraction 220 materials. Next, the materials are dried in a step entitled Drying 510. After that, the materials are separated in a step called Air Classification 530, which separates out waste such as, labels, low density polyethylene, Styrofoam, gloves, fibers, and textiles. After that, Density Separation and/or Electrostatic Separation 550 is used to separate the materials into polypropylene and high density polyethylene.

(34) FIG. 6 at point “F” continues to point “F” on FIG. 7, where a step entitled Rinse 245 involves rinsing the Secondary Bottom Fraction group 240 materials. After that, in a step entitled Drying 520, the materials are dried. Next, the materials are separated in a step called Air Classification 540, which separates out waste such as, labels, low density polyethylene, Styrofoam, gloves, fibers, and textiles. After that, Density Separation 560 is used to separate the materials into segregated heavy plastics, such as nylon, ABS, and other heavy plastics. Density Separation 600 is used to separate out rubber.

(35) FIG. 6 at point “G” continues to point “G” on FIG. 7, where a step entitled Drying 570, involves drying the Primary Bottom Fraction 300 materials. After that, Magnets 580 are used to separate out the ferrous metal materials. Next, nonferrous metal materials and mixed glass cullet are separated out with Eddy Currents 590, which extracts nonferrous metals by producing an electromagnetic field.

(36) With reference to FIG. 8, another alternative method of separating and cleaning treated medical waste is described to separate it into its component materials for recycling. The method comprising first receiving Material Feed 110. Next, the Material Feed 110 undergoes Size Reduction 120 by shredding it into small parts to expose the interior. The Material Feed 110 is then washed in a caustic solution in a hot sink/float tank to remove biologic contamination during Washing 130, where the gunk coated materials are submerged into a caustic solution that may comprise sodium hydroxide, potassium hydroxide, or a similar chemical. This caustic solution Washing 130 is highly effective in breaking down and dissolving gunk off of the materials. The pH level for the caustic solution may preferably be in the range of 11 pH to 12.5 pH, and the temperature of the caustic solution may preferably be in the range of between 120 degrees F. to 140 degrees F.

(37) The materials are then separated into a Primary Top Fraction group 200 that comprises polypropylene, polyethylene, labels, Styrofoam, fibers, and rubbers; and a Primary Bottom Fraction group 300 that comprises glass and metals, such as steel, stainless steel, and titanium.

(38) Next, the Primary Top Fraction group 200 further undergoes Rinse 225, where the materials are rinsed. After that, the materials undergo a step called Drying 510, where the materials are dried. Next, the materials are separated in a step called Air Classification 530. After that, high intensity Magnets 585 are used to separate out stainless steel. Next, Density Separation and/or NIR Sorting 555 is used to separate the materials into polypropylene, polyethylene, polystyrene, nylon, ABS, Polyethylene Terephthalate (“PET”), rubber, and other heavy plastics. As previously discussed, NIR Sorting involves using the wavelength for different material chemistries of mixed plastics to sort colored resins composed of different polymers.

(39) The materials in the Primary Bottom Fraction group 300 are also rinsed in a step entitled Rinse 245. After that, in a step entitled Drying 520, the materials are dried. Next, the ferrous metal materials are separated out with Magnets 580. After that, the nonferrous metal materials are separated out with Eddy Currents 590. Next, High Intensity Magnets 585 separate the materials into stainless steel, titanium, and glass.

(40) All of these embodiments and the invention disclosed herein are intended to be within the scope herein disclosed. These and other embodiments of the invention will become readily apparent to those skilled in the art from the detailed description of the preferred embodiments having reference to the attached figures, the embodiments not being limited to any particular, preferred embodiments disclosed. Also, the invention disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.