WO2011072136A2

WO2011072136A2 - Method and system for the processing of medical and other wastes with integrated waste to energy conversion

Info

Publication number: WO2011072136A2
Application number: PCT/US2010/059711
Authority: WO
Inventors: Scott Timothy Bolo; Janet Lea Norman
Original assignee: The Insite Group Re Llc
Priority date: 2009-12-11
Filing date: 2010-12-09
Publication date: 2011-06-16
Also published as: WO2011072136A3

Abstract

The present invention provides waste-to-energy systems for processing medical and other wastes while concurrently recycling recoverable products and generating energy, including electrical energy, from the waste materials. Methods of processing the medical and other wastes and converting such waste materials to energy also are described.

Description

METHOD AND SYSTEM FOR THE

PROCESSING OF MEDICAL AND OTHER WASTES WITH INTEGRATED WASTE TO ENERGY CONVERSION

This application is being filed on 09 December 2010, as a PCT International Patent application in the name of The InSite Group RE LLC, a U.S. national corporation, applicant for the designation of all countries except the US, and Scott Timothy Bolo and Janet Lea Norman, both citizens of the U.S., applicants for the designation of the US only, and claims priority to U.S. Provisional patent application Serial No. 61/282,074, filed on December 11, 2009, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates generally to methods, systems, and apparatus for processing waste materials while concurrently converting the waste materials to energy.

Infectious and medical waste is refuse that can transmit disease. Generators of medical waste include facilities that can include, but are not limited to, hospitals, doctors' offices, clinics, dental offices, laboratories, nursing homes, funeral parlors, and the like. In addition, as medical costs rise, more long-term illnesses are being treated at home, and medical waste is often being mixed with ordinary household garbage. In recent years, the amount of medical waste has increased dramatically, some of which can be attributed to the increased use of disposable products rather than reusable products. Moreover, in many jurisdictions, the definition of medical waste has been broadened to include an ever increasing variety of materials. The

Centers for Disease Control has issued recommended procedures whereby any material that may come into contact with a patient's bodily fluids should be treated as if it were infectious. Examples of waste materials, therefore, can include bandages, gloves, tubing, syringes, laboratory cultures, and pathological wastes, among others. This medical waste can be isolated in special sealed containers until the waste can be treated. Infectious bacteria, viruses, and organisms normally can be destroyed by some form of heat. The most widely used forms of such treatment can include autoclaving, or sterilization with steam, and burning at specially equipped incineration sites, since most hospital incinerators do not meet pollution control and other regulatory standards, and are extremely inefficient to operate. Certain incineration and waste treatment apparatus are disclosed in, for example, DE 3400189, FR 2817151, and U.S. Patent Publication Nos.

2001/0009969, 2003/0221597, 2006/0112639, and 2009/0217848, the disclosures of which are incorporated herein by reference in their entirety. However, the methodologies employed therein do not consider the benefits of segregating mixed waste into discrete solid and liquid components, of the strategic processing of these discrete solid and liquid components, of integrated energy recovery, of system self- sufficiency, and of generating electrical energy from processed materials (e.g., bio- solids, bio-gases, fuel oils, etc.), amongst other considerations.

Therefore, there is still a need to provide an alternative waste treatment system and method which enables the discrete treatment of different waste streams with one integrated system by, for example, incineration, oxidative steam- pressurization, wastewater treatment, and pyrolysis; and in doing so, both recover recyclable materials and generate bio-fuels for recovery and use in waste-to-energy generation.

Overriding issues that producers of medical waste face are increasing waste disposal costs, recovery of recyclable materials, and energy efficiency. It would be beneficial if medical and other wastes could be efficiently processed, but integrated with this waste processing, the refined waste streams could be utilized to generate energy. The energy could, therefore, be used to drive various apparatus used in the waste processing to improve the overall energy efficiency, reduce the overall costs, and reduce the environmental impact of the system. Accordingly, it is to these ends that the present invention is directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify required or essential features of the claimed subject matter. Nor is this summary intended to be used to limit the scope of the claimed subject matter.

The present invention generally relates to waste-to-energy systems for processing medical and other wastes. Such waste-to-energy systems can generate energy, including electrical energy, from the waste materials. Also disclosed herein are methods of processing the medical and other wastes, and converting these waste materials to energy.

Aspects of the present invention are directed to separating liquid waste from solid waste, and treating the respective waste streams in a manner that is more suitable for each. Such a methodology can improve both energy and cost efficiency. Due to the diverse nature of medical waste, effective treatment of the entire waste stream under one treatment regime is impractical. For instance, animal parts, pathological wastes, and pharmaceuticals in a waste stream often can be disposed of in an incinerator, while certain medical instruments, glass, and plastics, can be sterilized, cleaned, and recycled, instead of incinerated.

Additionally or alternatively, aspects of the present invention are directed to processing a waste stream having a liquid content of the waste stream of over 50%, such as, for instance, over 60%, over 70%, or over 75%.

Additionally or alternatively, aspects of the present invention are directed to segregating certain plastics, metals, and other recoverable materials from a solid waste stream, using the plastics for energy generation, and recovering the useful metals and other recoverable materials (i.e., glass) for recycling. Recycling of such materials can be beneficial, both environmentally and economically.

Additionally or alternatively, aspects of the present invention are directed to a waste processing system that can be a net generator of electricity. Excess electricity generated in the waste processing system can be sold to the electrical grid.

Additionally or alternatively, aspects of the present invention are directed to utilizing waste materials and/or the processing of waste materials to generate heat energy and/or electrical energy.

Additionally or alternatively, aspects of the present invention are directed to minimizing the volume of waste materials that have to be landfilled.

Additionally or alternatively, aspects of the present invention are directed to maximizing the recovery of recyclable materials and/or inert components of liquid and solid waste streams. Medical waste often contains a number of recyclable materials such as PVC, PET, HDPE, biomass, precious and semi-precious metals, among others. It can be beneficial for these recyclable materials to be recovered, instead of being either burned or landfilled.

Additionally or alternatively, aspects of the present invention are directed to minimizing the environmental footprint of a waste processing system, and to meeting or exceeding all applicable regulatory standards for the treatment and disposal of medical waste.

Additionally or alternatively, aspects of the present invention are directed to a waste processing system that requires no external power or energy from outside sources. For instance, the system can be a stand-alone waste processing system in which the electricity generated on-site can be sufficient to supply the needs of the other components of the waste processing system. Accordingly, in these and other aspects, the waste-to-energy system can be skid-mounted and deployed to remote areas.

Both the foregoing summary and the following detailed description provide examples and are explanatory only. Accordingly, the foregoing summary and the following detailed description should not be considered to be restrictive. Further, features or variations may be provided in addition to those set forth herein. For example, certain aspects and embodiments may be directed to various feature combinations and sub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various aspects and embodiments of the present invention. In the drawings:

FIG. 1 is a process flow schematic diagram of a waste processing and waste- to-energy system of an embodiment of the present invention.

FIG. 2 is a process flow schematic diagram of a waste processing and waste- to-energy system of another embodiment of the present invention.

DEFINITIONS

To define more clearly the terms used herein, the following definitions and conventions are provided.

While systems and methods are described in terms of "comprising" various apparatus or steps, the systems and methods can also "consist essentially of or "consist of the various apparatus or steps, unless stated otherwise.

Although any systems, apparatus, methods, and steps similar or equivalent to those described herein can be used in the practice or testing of the invention, the typical systems, apparatus, methods, and steps are herein described. All publications and patents mentioned herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the constructs and methodologies that are described in the publications, which might be used in connection with the presently described invention. The publications discussed throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention.

The terms "a," "an," and "the" are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of "a boiler," "an outlet," etc., is meant to encompass one, or more than one, boiler, outlet, etc., unless otherwise specified.

The term "contacting" is used herein to describe components or materials that are contacted together in any order, in any manner, and for any length of time. For example, contacting of the components or materials can be accomplished by blending, mixing, or any suitable method. Further, the "contacting" of the various components or materials can result in mixtures, blends, solutions, slurries, reaction products, and the like, or combinations thereof. The contacting of two or more components can result in, for instance, a reaction product or a reaction mixture. Consequently, depending upon the circumstances, a "contacting" step can result in a mixture, a reaction mixture, a reaction product, a solution, etc.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description refers to the accompanying drawings.

Wherever possible, similar reference numbers are used in the drawings and the following description to refer to the same or similar elements. While aspects and embodiments of the invention may be described, modifications, adaptations, and other implementations are possible. For example, substitutions, additions, or modifications may be made to the elements illustrated in the drawings, and the methods described herein may be modified by substituting, reordering, or adding stages to the disclosed methods. Accordingly, the following detailed description does not limit the scope of the invention.

The present invention is directed generally to the processing of medical and other wastes, integrated with the utilization of the medical and other wastes to generate energy which can be used to process the medical and other wastes. In an aspect, the system can be a facility fueled in whole or in part by the processing of the inputted waste materials. Other aspects are directed to a waste-to-energy (WTE) system capable of running on various waste materials as fuel, and strategically disposing of the waste materials while producing electricity simultaneously.

In accordance with certain aspects and embodiments of the present invention, a medical waste processing and waste-to-energy system is provided herein. One such system can comprise:

(i) a separation apparatus for separating liquid medical waste from solid medical waste in a medical waste stream entering the system, with a first separation apparatus outlet comprising water, a second separation apparatus outlet comprising solid medical waste, and an optional third separation apparatus outlet comprising digester gas and bio solids;

(ii) a heated vessel for cleaning and disinfecting the solid medical waste from the separation apparatus, with a first heated vessel outlet comprising mixed solid waste and a second heated vessel outlet comprising a suspension of solids;

(iii) a sorting apparatus for separating lighter plastic solid waste from heavy solid waste, with a first sorting apparatus outlet comprising plastic solid waste, a second sorting apparatus outlet comprising recyclable heavy solid waste, and a third sorting apparatus outlet comprising non-recyclable heavy solid waste;

(iv) a pressurized oxidation chamber for sterilizing the recyclable heavy solid waste from the sorting apparatus, with an oxidation chamber outlet comprising sterilized recyclable solid waste;

(v) a pyrolysis chamber for converting the plastic solid waste from the sorting apparatus to fuel oils, and a pyrolysis chamber outlet comprising fuel oils;

(vi) an incinerator for burning a portion of the non-recyclable heavy solid waste from the sorting apparatus, with a first incinerator outlet comprising ash and a second incinerator outlet comprising hot gas;

(vii) a heat exchanger for converting the hot gas from the incinerator into steam, with a heat exchanger outlet comprising steam and optionally hot air for use throughout the system;

(viii) a metals recovery system for removing recyclable metals from the ash present in the first incinerator outlet;

(ix) a boiler for converting waste products present in the system to steam, with a boiler outlet comprising steam for use throughout the system; and (x) a turbine and generator for converting steam to electricity, with a turbine and generator outlet comprising electricity for use throughout the system and optionally for use in conveying energy for sale to the electrical grid.

In accordance with aspects of the invention, this medical waste processing and waste-to-energy system can further comprise a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the boiler for transferring a portion of the fuel oils from the pyrolysis chamber to the boiler. The conduit or other means of conveyance can comprise any suitable means for transferring an outlet stream from one part of the system to another part of the system, and such means can include, but are not limited to, gravity flow, pumping, carrying, dumping, etc., whether manually or automated, and the like, including combinations thereof.

Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the incinerator for transferring a portion of the fuel oils from the pyrolysis chamber to the incinerator. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the boiler outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the boiler to the pressurized oxidation chamber. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the boiler outlet to an inlet of the turbine and generator for transferring a portion of the steam from the boiler to the turbine and generator. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the heat exchanger to the pressurized oxidation chamber.

Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the turbine and generator for transferring a portion of the steam from the heat exchanger to the turbine and generator. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the turbine and generator outlet to the pressurized oxidation chamber for supplying electrical power to the pressurized oxidation chamber. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the turbine and generator outlet to the electrical grid for supplying excess electrical power to the electrical grid. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the optional third separation apparatus outlet to an inlet of the boiler for transferring the digester gas and bio solids from the separation apparatus to the boiler and/or to the pyrolysis chamber. Additionally or

alternatively, the system can further comprise a conduit or other means of conveyance from the boiler to an inlet of the pyrolysis chamber for transferring a portion of the steam from the boiler to the pyrolysis chamber. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger to an inlet of the pyrolysis chamber for transferring a portion of the steam and/or hot air to the pyrolysis chamber.

In these and other aspects, the medical waste processing and waste-to-energy system can further comprise a HOH production device for using water (and optionally, with electrolytes) and electricity to produce HOH gas for use throughout the system. In such circumstances, the system can further comprise a conduit or other means of conveyance from the turbine and generator outlet to the HOH production device for supplying electrical power to the HOH production device.

In another aspect, the separation apparatus for separating liquid medical waste from solid medical waste in the medical waste stream entering the medical waste processing and waste-to-energy system can comprise:

(I) a screening or sorting device for separating the liquid medical waste from the solid medical waste, the screening or sorting device comprising the second separation apparatus outlet comprising the solid medical waste and a screening or sorting device outlet comprising liquid medical waste, for instance, as a solution or a suspension;

(II) a liquid waste sterilization vessel for sterilizing the liquid medical waste from the screening or sorting device with a liquid waste sterilization vessel outlet comprising sterile liquid waste;

(III) a neutralization or dilution tank for neutralizing and/or diluting the sterile liquid waste from the liquid waste sterilization vessel, with a tank outlet comprising diluted liquid waste; and

(IV) a waste water treatment apparatus for treating the diluted liquid waste from the neutralization or dilution tank, with the first separation apparatus outlet comprising water, and the third separation apparatus outlet comprising the digester gas and bio solids. In this and other aspects, the system can further comprise a conduit or other means of conveyance from the second heated vessel outlet to an inlet of the liquid waste sterilization vessel for transferring the suspension of solids from the heated vessel to the liquid waste sterilization vessel. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the waste water treatment apparatus for transferring a portion of the hot air from the heat exchanger to the waste water treatment apparatus.

Another waste-to-energy system described herein for the processing of medical and other wastes can comprise at least the following:

(a) a pressurized oxidation chamber for sterilizing recyclable solid medical waste entering the system, with an oxidation chamber outlet comprising sterilized waste;

(b) an incinerator for burning miscellaneous medical waste entering the system, with a first incinerator outlet comprising ash and a second incinerator outlet comprising hot gas;

(c) a heat exchanger for converting the hot gas from the incinerator into steam, with a heat exchanger outlet comprising steam and optional hot air for use throughout the system;

(d) a boiler for converting waste products present in the system to steam, with a boiler outlet comprising steam for use throughout the system; and

(e) a turbine and generator for converting steam to electricity, with a turbine and generator outlet comprising electricity for use throughout the system and optionally for use in conveying energy for sale to the electrical grid.

In certain aspects, this medical waste processing and waste-to-energy system can further comprise a pyrolysis chamber for converting medical waste plastics to fuel oils, and a pyrolysis chamber outlet comprising fuel oils. Additionally, this system can further comprise a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the boiler for transferring a portion of the fuel oils from the pyrolysis chamber to the boiler. The conduit or other means of conveyance, as noted above, can comprise any suitable means for transferring an outlet stream from one part of the system to another part of the system, and such means can include, but are not limited to, gravity flow, pumping, carrying, dumping, etc., whether manually or automated, and the like, including combinations thereof. Moreover, the system can further comprise a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the incinerator for transferring a portion of the fuel oils from the pyrolysis chamber to the incinerator. It is also contemplated that the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pyrolysis chamber for transferring a portion of the hot air from the heat exchanger to the pyrolysis chamber.

In a particular aspect of the invention, the system can further comprise a vessel for digesting solid medical waste entering the system, with a vessel outlet comprising digester gas and bio solids. In this aspect, the system can further comprise a conduit or other means of conveyance from the vessel outlet to an inlet of the boiler for transferring the digester gas and bio solids from the vessel to the boiler. In other aspects, a portion of the bio solids can be transferred to the pyrolysis chamber.

Additionally or alternatively, the medical waste processing and waste-to- energy system can further comprise a conduit or other means of conveyance from the boiler outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the boiler to the pressurized oxidation chamber.

Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the boiler outlet to an inlet of the turbine and generator for transferring a portion of the steam from the boiler to the turbine and generator. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the boiler outlet to an inlet of the pyrolysis chamber for transferring a portion of the steam from the boiler to the pyrolysis chamber.

Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the heat exchanger to the pressurized oxidation chamber. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the turbine and generator for transferring a portion of the steam from the heat exchanger to the turbine and generator. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pyrolysis chamber for transferring a portion of the steam from the heat exchanger to the pyrolysis chamber. Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the turbine and generator outlet to the pressurized oxidation chamber for supplying electrical power to the pressurized oxidation chamber.

Additionally or alternatively, the system can further comprise a conduit or other means of conveyance from the turbine and generator outlet to the electrical grid for supplying excess electrical power to the electrical grid.

In other aspects and embodiments of the present invention, methods of processing medical waste and converting waste to energy are disclosed and described. One such method, in which the medical waste can comprise solid medical waste, plastic medical waste, heavy recyclable medical waste, and miscellaneous solid waste, can comprise the following steps:

(A) digesting the solid medical waste to produce a mixture comprising digester gas and bio solids;

(B) contacting the heavy recyclable medical waste with ozone and steam to produce sterilized waste;

(C) heating and converting the plastic medical waste to fuel oils;

(D) incinerating the miscellaneous solid waste to produce incinerator ash and hot gas;

(E) producing a first steam stream and optional hot air from the hot gas;

(F) burning the digester gas, the bio solids, and a first portion of the fuel oils to produce a second steam stream; and

(G) converting a portion of the first steam stream and a portion of the second steam stream to electricity.

In this method of processing medical waste and converting waste to energy, Applicant also contemplates that a second portion of the fuel oils can be used to fire the incinerator. Additionally or alternatively, a portion of first steam stream and/or a portion of the second steam stream can be used to supply the steam in step (B). Additionally or alternatively, a portion of the electricity can be used to produce the ozone in step (B). Additionally or alternatively, a portion of the electricity can be supplied to the electrical grid. Additionally or alternatively, the electricity generated in step (G) can exceed an amount required to process the solid medical waste, the plastic medical waste, the heavy recyclable medical waste, and the miscellaneous solid waste in this method. Additionally or alternatively, a portion of the steam and/or hot air generated in steps (E) and (F) can be used to produce the fuel oils in step (C).

Another method of processing medical waste and converting waste to energy is provided, in which the medical waste can comprise liquid medical waste and solid medical waste. This method can comprise:

(1) separating the liquid medical waste from the solid medical waste to produce a liquid waste stream and a solid waste stream;

(2) contacting the solid waste stream with a disinfecting agent at a temperature in a range from about 50°C to about 150°C to produce a cleaned mixture of solid waste;

(3) separating the cleaned mixture of solid waste into a first stream comprising lighter plastic solid waste, a second stream comprising recyclable heavy solid waste, and a third stream comprising non-recyclable heavy solid waste;

(4) contacting the recyclable heavy solid waste with ozone and steam to produce a sterilized recyclable waste stream;

(5) heating and converting the plastic solid waste to fuel oils;

(6) incinerating the non-recyclable heavy solid waste to produce incinerator ash and hot gas;

(7) producing a first steam stream and optional hot air from the hot gas;

(8) burning a first portion of the fuel oils to produce a second steam stream; and

(9) converting a portion of the first steam stream and a portion of the second steam stream to electricity.

In accordance with certain aspects of the invention, a portion of the electricity in this method of processing medical waste and converting waste to energy can be used to gasify water to produce HOH gas. Additionally or alternatively, a second portion of the fuel oils can be incinerated. Additionally or alternatively, a portion of first steam stream and/or a portion of the second steam stream can be used to supply the steam in step (4). Additionally or alternatively, a portion of the electricity can be used to produce the ozone in step (4). Additionally or alternatively, a portion of the electricity can be supplied to the electrical grid.

Additionally or alternatively, the electricity generated in step (9) can exceed an amount required to process the liquid medical waste and the solid medical waste in this method of processing medical waste and converting waste to energy. It is also contemplated that step (1) in this method of processing medical waste and converting waste to energy can comprise the steps of:

(I) segregating the medical waste to produce the solid medical waste and the liquid medical waste;

(II) sterilizing the liquid medical waste to produce sterile liquid waste;

(III) neutralizing and/or diluting the sterile liquid waste to produce diluted liquid waste; and

(IV) treating the diluted liquid waste in a waste water treatment apparatus to produce water, digester gas, and bio solids.

Various aspects and embodiments of the systems and methods consistent with the present invention will hereinafter be described with reference to the accompanying drawings. For clarity, not all inlet and outlet streams are shown or labeled in the drawings, nor are all inlet and outlet streams required.

FIG. 1 illustrates an embodiment of the invention directed to a waste processing system 1 with concurrent waste-to-energy generation. A waste stream comprising medical and/or other wastes can be fed to a separation apparatus 5. The separation apparatus 5 can be any suitable means for separating liquid waste from solid waste. For instance, separation apparatus 5 can utilize sorting or pre-sorting to separate liquid waste from solid waste. Additionally or alternatively, separation apparatus 5 can comprise screens and/or centrifugation to facilitate the separation of liquids from solids. While not wishing to be bound by theory, Applicant believes that, in some instances, greater than half of medical waste can be in liquid form, but the liquid waste is often treated in a waste stream as if it were a solid. By the use of a separation apparatus 5, a waste stream comprising a substantial portion of liquids

(e.g., often greater than 50%) can be segregated into primarily liquid and primarily solid streams to reduce and/or eliminate the amount of liquid waste that is further processed in a manner that may be more suitable for solid waste stream processing.

Generally, the separation apparatus 5 can be operated at ambient or room

temperature, typically about 20-35°C, although this is not a requirement. Solid materials can be mixed, homogenized, and reduced in average size through a combination of operations including, but not limited to, crushing, shredding, and the like, in the separation apparatus 5. The output liquids stream and the output solids streams can be fed to a liquid waste sterilization apparatus 10 and a solid waste disinfecting apparatus 20, respectively. Alternatively, liquid waste and solid waste can be separated off-site, and the liquid waste stream can be fed directly to the liquid waste sterilization apparatus 10, while the solid waste stream can be fed directly to the solid waste disinfecting apparatus 20.

The liquid waste sterilization apparatus 10 can comprise a vessel or holding tank where liquid waste can be sterilized through the application of bactericidal chemicals (e.g., chlorine, sodium hypochlorite, glutaraldehyde, formaldehyde, peroxide, ozone, and the like, including combinations thereof), or through the application of high pH and high temperature and pressure (e.g., pH of 12-13 and high temperature and pressure), or any combination thereof. In some aspects, the liquid waste can be sterilized via chemical means, while in other aspects, the liquid waste can be sterilized with steam under elevated temperature and/or pressure.

Generally, the temperature can be in a range from 100 to 200°C, and the pressure can be in a range from 15 to 50 psig. In yet another aspect, the liquid waste sterilization apparatus 10 can comprise an autoclave. Prior to discharge of the effluent from the liquid waste sterilization apparatus 10 to the dilution and neutralization apparatus 15, the effluent can be tested and verified as being sterile or non-infectious.

Sterilized liquid/effluent entering the dilution and neutralization apparatus 15 can be neutralized and/or diluted to quench any reactive biocidal materials or sterilization materials in the sterilized liquid/effluent. The dilution and

neutralization apparatus can comprise a mixing tank, and in some aspects, dilution water can be added to the sterilized liquid. After thorough mixing, the liquid outflow stream can be tested to confirm that it has been diluted and/or neutralized sufficiently, so that this outflow does not adversely affect microbial cultures or other materials in a downstream waste water treatment apparatus 17.

The diluted liquid stream can enter the waste water treatment apparatus 17, which can comprise any suitable waste water treatment plant equipment, such as, an aeration pond, a clarifier, a digester, a sludge drying bed, etc., and combinations thereof. In an aspect, any resultant solids from the clarifier can be transferred to a digester and then to drying beds. One output stream from the waste water treatment apparatus 17 can comprise digester gas and/or bio solids, and this stream can be fed to a boiler 65, to be discussed further below, so that the energy/fuel from these waste materials can be recovered and used in the waste-to-energy system 1 illustrated in

FIG. 1. Another output stream from the waste water treatment apparatus 17 can comprise water, some of which can be recycled for use as dilution water in the dilution and neutralization apparatus 15.

A solid waste stream from the separation device 5 can be fed into the solid waste disinfecting apparatus 20. Additionally or alternatively, off-site solid waste can be fed into the solid waste disinfecting apparatus 20. The solid waste disinfecting apparatus 20 can comprise a vessel configured to wash and/or deodorize and/or disinfect the solid waste stream. For instance, solid materials fed into the solid waste disinfecting apparatus 20 can be contacted with detergent, alkaline salts, and/or other chemicals to disinfect and start to break down waste proteins and to counterbalance any acids and odors in the waste stream. Steam, water jets, and agitation all can be used to break down any remaining biological materials in the solid waste and convert such materials to liquid from. Heat via hot air or other suitable means can be used to melt fats and lipids, as well as to melt agar that may be present in any microbial waste. In some aspects, the solid waste disinfecting apparatus 20 can be operated at an elevated temperature, such as in a range from about 50°C to about 150°C, from about 60°C to about 120°C, from about 75°C to about 110°C, or from about 75°C to about 95°C, for example. The solid waste disinfecting apparatus 20 can comprise a compaction and/or a drying phase.

Additionally, the solid waste disinfecting apparatus 20 can have an outlet stream comprising a suspension of solids and/or bio-solids (colloids, small pieces of solid organic and inorganic medical waste material, and the like), and this stream can be fed to the liquid waste sterilization apparatus 10.

Solid waste exiting the solid waste disinfecting apparatus 20 can enter a solids sorting apparatus 25. The solids separation apparatus 25 can be configured to sort or separate lighter density, plastic materials from the remainder of the solid waste, optionally followed by cleaning the plastic materials. In an aspect, the solids sorting apparatus 25 can comprise a flotation system, wherein lighter plastic materials float in a liquid medium (and heavier solids do not), and are collected in a separate stream leaving the solids separation apparatus 25. Additionally or alternatively, the sorting apparatus 25 can comprise hand sorting and/or a mechanical device for sorting the solid materials.

Generally, heavier recyclable materials exiting the solids separation apparatus 25 can enter a sterilization apparatus 30, which can comprise a pressurized oxidation chamber. The pressurized oxidation chamber can be configured to sterilize glass, surgical instruments, and other recyclable materials using steam and heat and ozone under pressure (typically, in the 10-50 psig range). The pressurized oxidation chamber can use electricity generated within the system 1 to produce ozone within the chamber. The ozone can break down any remaining proteins accompanying the waste and render the waste sterile. In an alternative aspect, the recyclable waste sterilization apparatus can comprise an autoclave. Prior to exiting the sterilization apparatus 30, the waste can be cleaned or washed, if needed, and then transferred to a plastic fuel oil recovery apparatus 35. Alternatively, this sterilized waste can be recycled and and/or re-used. Contaminated water and/or contaminated liquid from the pressurized oxidation chamber can be conveyed to the liquid waste sterilization apparatus 10.

Generally, plastic materials exiting the solids separation apparatus 25 can enter a fuel oil recovery apparatus. The plastic fuel oil recovery apparatus 35 can comprise a pyrolysis chamber. In this chamber, the temperature can be raised to between 200 and 1000°C to melt the recovered plastic wastes and, often, this melting process can be conducted in the absence of oxygen. Waste plastic in the pyrolysis chamber can be converted and separated into three exit streams: char residue, oil, and gas. The gas can be taken to a catalytic converter, which can convert the gas into a distillate fraction or a liquid vapor, and subsequently cooled in a condenser. After going through a recovery tank, the distillate can be separated from

contaminants through the use of a centrifuge or similar device. In another aspect, the waste plastic entering the pyrolysis chamber can be converted to fuel oils. The pyrolysis chamber can be heated by incinerator flue gasses or by burning of fuels recovered in the waste destruction process (e.g., HOH, fuel oil, digester gas) to generate heat. Typically, waste plastic has a high recovered value in a waste-to- energy process and/or system.

Solid wastes exiting the solids separation apparatus 25 as well as other special wastes that are presorted can enter an incineration apparatus 40. For instance, solid waste materials can be loaded into a hopper, charged into an incinerator, and burned. In some aspects, the incinerator can be beneficial because it may be the only practical way to dispose of some medical wastes that are too difficult to recycle otherwise (e.g., implanted materials, pathological waste, pharmaceuticals, some hazardous medical wastes, etc.). The incineration apparatus can provide heat to a heat recovery unit 45. The heat recovery unit can comprise a heat exchanger. The incinerator can be fired by reclaimed fuel oils from plastics, HOH gas, other waste materials such as bio diesel and reclaimed motor oil, for example, including combinations thereof, as well by the energy generated by the burning of the waste in the incinerator. To reduce emissions, the incinerator can comprise pollution control technology such as a wet scrubber, and any waste water exiting the scrubber can be fed to the waste water treatment apparatus 17.

Hot gases leaving the incineration apparatus 40 can be at temperatures of 950-1000°C, and above, and these high temperatures can be useful for both energy recovery and for processing of other waste materials. In one aspect, hot dry gas can be used to dry and/or heat materials in the solid waste disinfecting apparatus 20 and/or provide process heat to the plastic fuel oil recovery apparatus 35.

Additionally or alternatively, hot dry gas can be used to dry and/or heat sludge in drying beds that may be part of the waste water treatment apparatus 17.

Additionally, heat from the incineration apparatus 40 can be processed through the heat recovery unit 45 (e.g., through a heat exchanger) to produce steam. Steam generated in the heat recovery unit 45 can provide steam for, as an example, the solid waste disinfecting apparatus 20 and/or the plastic waste sterilization apparatus 30 and/or the fuel oil recovery apparatus 35 and/or an electrical generation apparatus 55.

Ash from the incineration apparatus 40 can be fed to a metals recovery apparatus 50, if desired. Additionally, ash from the plastic fuel oil recovery apparatus 35 can be fed to the metal recovery apparatus 50. The ash can be processed using metal recovery techniques - such as, for example, based on magnetism - to recover useful metals from the remaining waste, including but not limited to, platinum, chromium, ferrous metals, aluminum, and the like, including mixtures, alloys, or other combinations thereof. Other waste exiting the metals recovery apparatus 50 can be non-recyclable waste and can be sent to a landfill for disposal.

The electrical generation apparatus 55 can comprise a turbine and a generator. In one aspect, steam produced via the incineration apparatus 40 and the heat recovery unit 45, and additionally, steam generated from a boiler 65 can be used to power a turbine, which rotates a generator to produce electrical power.

Electrical energy in FIG. 1 can be created from the waste products and streams processed therein. Electrical power generated in the electrical generation apparatus 55 can be used throughout the waste-to-energy system 1 and other plant operations. In one aspect, the turbine and generator can be configured to produce all of the electricity required in the waste processing system 1. For instance, electrical energy can be used to operate a water gasification unit 60 and the plastic waste sterilization apparatus 30, among others. It is also contemplated the excess electrical energy generated can be sold to the electrical power grid.

In some aspects, electrical energy can be used to operate the water gasification unit 60, one purpose of which can be to gasify water (or water with dilute potassium hydroxide) using electrodes into a gaseous state known as HOH. The HOH gas can be collected and compressed for use in the plant waste-to-energy operations including, for example, the incineration apparatus 40, a boiler 65, and the plastic fuel oil recovery apparatus 35. While not wishing to be bound by theory, Applicant believes that HOH gas can be beneficial because it burns at about 950- 1000°C, or more, potentially increasing the efficiency of the incineration apparatus 40, the boiler 65, and the plastic fuel oil recovery apparatus 35.

The boiler 65 can burn HOH gas, digester gas, biosolids, plastic fuel oils (gasoline, diesel, kerosene, etc.) and can complete the process of converting waste to energy. The boiler 65 also can be used to provide a steady source of heat and steam when the incineration apparatus 40 is not running, as well as to balance the heat and mass flows in the system 1 with the assistance of a program logic controller and operational forecasting. In an aspect, the boiler 65 can be configured to provide for the continuous generation of electrical power. To reduce emissions, the boiler 65 can comprise pollution control technology such as a wet scrubber, and any waste water exiting the scrubber can be fed to the waste water treatment apparatus 17, which can be integrated into the system as shown in FIG. 1.

Referring now to FIG. 2, which illustrates another embodiment of the invention directed to a waste processing system 100 with concurrent waste-to- energy generation. Waste solids and liquids can be separated prior to being fed to the waste processing and waste-to-energy system 100.

A waste stream comprising medical waste solids can be fed to a vessel 120 for digesting. In this regard, the medical waste solids inlet stream typically can a water content of less than about 20%, less than about 10%, less than about 5%, or less than about 1%. The incoming waste stream can comprise an outlet stream of a waste water treatment plant or can comprise dehydrated medical waste. An outlet waste stream exiting the vessel 120 for digesting can comprise digester gas and/or bio solids, and this stream can be fed to a boiler 165 (optionally, bio solids can be fed to a plastic fuel oil recovery apparatus 135), so that the energy/fuel from these waste materials can be recovered and used in the waste to energy system 100 illustrated in FIG. 2. Alternatively, digester gas and bio solids from medical waste converted at a waste water treatment facility can be fed directly to the boiler 165. Further, some or all of the bio solids can be fed directly to the plastic fuel oil recovery apparatus 135.

A waste stream generally comprising recyclable medical waste materials can enter a waste sterilization apparatus 130, which can comprise a pressurized oxidation chamber. The pressurized oxidation chamber can be configured to sterilize recyclable materials using steam and heat and ozone under pressure. The pressurized oxidation chamber can use electricity generated within the system 100 to produce ozone within the chamber. The ozone can break down any remaining proteins accompanying the recyclable waste and render the waste sterile and/or odorless. In an alternative aspect, the waste sterilization apparatus can comprise an autoclave. Prior to exiting the waste sterilization apparatus 130, the recoverable materials can be cleaned or washed, if needed, and then transferred to a sorting and recovery area in some aspects contemplated herein.

A waste stream generally comprising plastic medical waste materials can enter a fuel oil recovery apparatus 135. The fuel oil recovery apparatus 135 can comprise a pyrolysis chamber. In this chamber, the temperature can be raised to melt the recovered plastic wastes; this melting process can be, and often is, conducted in the absence or substantial absence of oxygen. Waste plastic in the pyrolysis chamber can be converted and separated into three exit streams: char residue, oil, and gas. The gas can be taken to a catalytic converter, which can convert the gas into a distillate fraction or a liquid vapor, and subsequently cooled in a condenser. After going through a recovery tank, the distillate can be separated from contaminants through the use of a centrifuge or similar device. In another aspect, the waste plastic entering the pyrolysis chamber can be converted to fuel oils. The pyrolysis chamber can be heated by incinerator flue gasses or by burning of fuels recovered in the waste destruction process (e.g., HOH, fuel oil, digester gas) to generate heat. Typically, waste plastic has a high recovered value in a waste to energy process and/or system. Other or miscellaneous or special solid waste can enter an incineration apparatus 140. These solids can include, but are not limited to, animal carcasses, pathological wastes, pharmaceuticals, paper waste items, biological materials, and certain plastics, and combinations thereof. For instance, these solid waste materials can be loaded into a hopper, charged into an incinerator, and burned. In some aspects, the incinerator can be beneficial because it may be the only practical way to dispose of some medical wastes that are too difficult to recycle otherwise (e.g., implanted materials or pathological wastes). The incineration apparatus can provide heat to a heat recovery unit 145. The heat recovery unit can comprise a heat exchanger. The incinerator can be fired by fuel oils and bio-solids reclaimed from the medical wastes, reclaimed motor oil, biodiesel, HOH gas, for example, including combinations thereof, as well by the energy generated by the burning of other system waste in the incinerator. To reduce emissions, the incinerator can comprise pollution control technology such as a wet scrubber, and any waste water exiting the scrubber can be fed to a waste water treatment plant. Ash from the incineration apparatus 140 can be landfilled or, alternatively, fed to a metals recovery system, to recover useful metals from the remaining ahs waste, including but not limited to, platinum, chromium, ferrous metals, aluminum, and the like, including mixtures, alloys, or other combinations thereof.

Hot gases leaving the incineration apparatus 140 can be at temperatures of 950-1000°C, and above, and these high temperatures can be useful for both energy recovery and for processing of other waste materials. In one aspect, hot dry gas can be used to dry and/or heat materials in the solid waste disinfecting apparatus 120. Additionally, heat from the incineration apparatus 40 can be processed through the heat recovery unit 145 (e.g., through a heat exchanger) to produce steam. Steam and/or hot air generated in the heat recovery unit 145 can provide steam and/or hot air as needed to the solid waste disinfecting apparatus 120, and/or the plastic waste sterilization apparatus 130, and/or the fuel oil recovery apparatus 135, and/or an electrical generation apparatus 155, for example.

The electrical generation apparatus 155 can comprise a turbine and a generator. In one aspect, steam produced via the incineration apparatus 140 and the heat recovery unit 145, and additionally, steam generated from a boiler 165 can be used to power a turbine, which rotates a generator to produce electrical power.

Electrical energy in FIG. 2 can be created from the waste products and streams processed therein. Electrical power generated in the electrical generation apparatus 155 can be used throughout the waste-to-energy system 100 and other plant operations. In one aspect, the turbine and generator can be configured to produce all of the electricity required in the waste processing system 100. For instance, electrical energy can be used to operate the plastic waste sterilization apparatus 130, among others. It is also contemplated the excess electrical energy generated can be sold to the electrical power grid.

The boiler 165 can burn digester gas, biosolids, plastic fuel oils (gasoline, diesel, kerosene, etc.) and can complete the process of converting waste to energy. The boiler 165 also can be used to provide a steady source of heat and steam when the incineration apparatus 140 is not running, as well as to balance the heat and mass flows in the system 100 with the assistance of a program logic controller and operational forecasting. In an aspect, the boiler can supply steam to the fuel oil recovery apparatus 135. Additionally or alternatively, the boiler 165 can be configured to provide for the continuous generation of electrical power. To reduce emissions, the boiler 165 can comprise pollution control technology such as a wet scrubber, and any waste water exiting the scrubber can be fed to a waste water treatment plant.

While certain aspects and embodiments of the invention have been described, other aspects and embodiments may exist. Further, any disclosed methods' steps or stages may be modified in any manner, including by reordering steps and/or inserting or deleting steps, without departing from the invention. While the specification includes a detailed description and associated drawings, the invention's scope is indicated by the following claims. Furthermore, while the specification has been described in language specific to structural features and/or methodological acts, the claims are not limited to the features or acts described above. Rather, the specific features and acts described above are disclosed as illustrative aspects and embodiments of the invention. Various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present invention or the scope of the claimed subject matter.

Claims

CLAIMS I claim:

1. A medical waste processing and waste-to-energy system comprising:

(v) a pyrolysis chamber for converting the plastic solid waste from the sorting apparatus to fuel oils, with a pyrolysis chamber outlet comprising fuel oils;

2. The system of claim 1, further comprising a HOH production device for using water and electricity to produce HOH gas for use throughout the system.

3. The system of claim 2, further comprising a conduit or other means of conveyance from the turbine and generator outlet to the HOH production device for supplying electrical power to the HOH production device.

4. The system of any one of claims 1 to 3, wherein the separation apparatus for separating liquid medical waste from solid medical waste in the medical waste stream entering the system comprises:

(I) a screening or sorting device for separating the liquid medical waste from the solid medical waste, the screening or sorting device comprising the second separation apparatus outlet comprising the solid medical waste and a screening or sorting device outlet comprising liquid medical waste;

(IV) a waste water treatment apparatus for treating the diluted liquid waste from the neutralization or dilution tank, with the first separation apparatus outlet comprising water, and the third separation apparatus outlet comprising the digester gas and bio solids.

5. The system of claim 4, further comprising a conduit or other means of conveyance from the second heated vessel outlet to an inlet of the liquid waste sterilization vessel for transferring the suspension of solids from the heated vessel to the liquid waste sterilization vessel.

6. The system of claim 4, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the waste water treatment apparatus for transferring a portion of the hot air from the heat exchanger to the waste water treatment apparatus.

7. The system of any one of claims 1 to 6, further comprising a conduit or other means of conveyance from the optional third separation apparatus outlet to an inlet of the boiler for transferring the digester gas and bio solids from the separation apparatus to the boiler.

8. The system of any one of claims 1 to 7, further comprising a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the boiler for transferring a portion of the fuel oils from the pyrolysis chamber to the boiler.

9. The system of any one of claims 1 to 8, further comprising a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the incinerator for transferring a portion of the fuel oils from the pyrolysis chamber to the incinerator.

10. The system of any one of claims 1 to 9, further comprising a conduit or other means of conveyance from the boiler outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the boiler to the pressurized oxidation chamber.

11. The system of any one of claims 1 to 10, further comprising a conduit or other means of conveyance from the boiler outlet to an inlet of the turbine and generator for transferring a portion of the steam from the boiler to the turbine and generator.

12. The system of any one of claims 1 to 11, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the heat exchanger to the pressurized oxidation chamber.

13. The system of any one of claims 1 to 12, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the turbine and generator for transferring a portion of the steam from the heat exchanger to the turbine and generator.

14. The system of any one of claims 1 to 13, further comprising a conduit or other means of conveyance from the turbine and generator outlet to the pressurized oxidation chamber for supplying electrical power to the pressurized oxidation chamber.

15. The system of any one of claims 1 to 14, further comprising a conduit or other means of conveyance from the turbine and generator outlet to the electrical grid for supplying excess electrical power to the electrical grid.

16. A medical waste processing and waste-to-energy system comprising:

17. The system of claim 16, further comprising a pyrolysis chamber for converting medical waste plastics to fuel oils, with a pyrolysis chamber outlet comprising fuel oils.

18. The system of claim 17, further comprising a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the boiler for transferring a portion of the fuel oils from the pyrolysis chamber to the boiler.

19. The system of claim 17, further comprising a conduit or other means of conveyance from the pyrolysis chamber outlet to an inlet of the incinerator for transferring a portion of the fuel oils from the pyrolysis chamber to the incinerator.

20. The system of claim 17, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pyrolysis chamber for transferring a portion of the hot air from the heat exchanger to the pyrolysis chamber.

21. The system of any one of claims 16 to 20, further comprising a vessel for digesting solid medical waste entering the system, with a vessel outlet comprising digester gas and bio solids.

22. The system of claim 21 , further comprising a conduit or other means of conveyance from the vessel outlet to an inlet of the boiler for transferring the digester gas and bio solids from the vessel to the boiler.

23. The system of any one of claims 16 to 22, further comprising a conduit or other means of conveyance from the boiler outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the boiler to the pressurized oxidation chamber.

24. The system of any one of claims 16 to 23, further comprising a conduit or other means of conveyance from the boiler outlet to an inlet of the turbine and generator for transferring a portion of the steam from the boiler to the turbine and generator.

25. The system of any one of claims 16 to 24, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the pressurized oxidation chamber for transferring a portion of the steam from the heat exchanger to the pressurized oxidation chamber.

26. The system of any one of claims 16 to 25, further comprising a conduit or other means of conveyance from the heat exchanger outlet to an inlet of the turbine and generator for transferring a portion of the steam from the heat exchanger to the turbine and generator.

27. The system of any one of claims 16 to 26, further comprising a conduit or other means of conveyance from the turbine and generator outlet to the pressurized oxidation chamber for supplying electrical power to the pressurized oxidation chamber.

28. The system of any one of claims 16 to 27, further comprising a conduit or other means of conveyance from the turbine and generator outlet to the electrical grid for supplying excess electrical power to the electrical grid.

29. A method of processing medical waste and converting waste to energy, the medical waste comprising solid medical waste, plastic medical waste, heavy recyclable medical waste, and miscellaneous solid waste, the method comprising:

(C) heating and converting the plastic medical waste to fuel oils;

(E) producing a first steam stream and optional hot air from the hot gas;

30. The method of claim 29, wherein a second portion of the fuel oils is incinerated.

31. The method of claim 29 or 30, wherein a portion of first steam stream and/or a portion of the second steam stream are used to supply the steam in step (B).

32. The method of any one of claims 29 to 31 , wherein a portion of the electricity is used to produce the ozone in step (B).

33. The method of any one of claims 29 to 32, wherein a portion of the electricity is supplied to the electrical grid.

34. The method of any one of claims 29 to 33, wherein the electricity generated in step (G) exceeds an amount required to process the solid medical waste, the plastic medical waste, the heavy recyclable medical waste, and the miscellaneous solid waste.

35. A method of processing medical waste and converting waste to energy, the medical waste comprising liquid medical waste and solid medical waste, the method comprising:

(5) heating and converting the plastic solid waste to fuel oils;

(7) producing a first steam stream and optional hot air from the hot gas; (8) burning a first portion of the fuel oils to produce a second steam stream; and

36. The method of claim 35, wherein a portion of the electricity is used to gasify water to produce HOH gas.

37. The method of claim 35 or 36, wherein a second portion of the fuel oils is incinerated.

38. The method of any one of claims 35 to 37, wherein a portion of first steam stream and/or a portion of the second steam stream are used to supply the steam in step (4).

39. The method of any one of claims 35 to 38, wherein a portion of the electricity is used to produce the ozone in step (4).

40. The method of any one of claims 35 to 39, wherein a portion of the electricity is supplied to the electrical grid.

41. The method of any one of claims 35 to 40, wherein the electricity generated in step (9) exceeds an amount required to process the liquid medical waste and the solid medical waste.

42. The method of any one of claims 35 to 41, wherein step (1) comprises the steps of:

(II) sterilizing the liquid medical waste to produce sterile liquid waste;