MEDICAL WASTES AND THEIR DISPOSAL STRATEGY

Dr. Chimezie Anyakora

A medical waste is all waste material generated at health care facilities such as clinics, physician’s office, dental practices, blood banks, and vertinary hospicals/clinics, as well as medical research facilities and laboratories.

Also defined as any solid waste that is generated in the diognosis, treatment, or immunization of human beings or animals, in research pertaining thereto, or in the production or testing of biologicals.

DEFINITION

Medical WasteA Comprehensive classification of hospital waste

REGULATED MEDICAL WASTE

Regulated Medical Waste is a subset of all medical wastes and include seven distinct categories:1. Cultures and stocks of infectious agents.2. Human pathological wastes (e.g. tissues, body parts)3. Human blood and blood products4. Sharps (e.g. hypodermic needles and syringes)5. Certain animal wastes6. Certain isolation wastes (e.g. wastes from patients with highly communicable diseases)7. Unused sharps.

INFECTIOUS WASTE

EPA has provided the following guidance on what constitutes an infectious waste. These factors include:1. Presence of a pathogen of sufficient virulence2. Dose3. Portal of entry 4. Resistance of hostThus, for a waste to be infectious, it must contain a pathogen with sufficient virulence and quantity so that exposure to the waste by a person or animal could result in an infectious disease.

INFECTIOUS WASTE

EPA categorizes infectious wastes into the following seven categories:1. Isolation wastes – wastes generated by hospitalized patients who are isolated to protect others from communicable diseases.2. Cultures and stocks of infectious agents and associated biologicals – this category includes: - Specimens from medical and biological laboratories - Cultures and stocks of infectious agents from clinical, research, and industrial laboratories3. Human blood and blood products – this includes waste blood, serum, plasma, and blood products.

INFECTIOUS WASTE

4. Pathological waste – tissues, organs, body parts, blood, and body fluids. 5. Contaminated sharps – contaminated hypodermic needles, syringes, scalpel blades, Pasteur pipettes, and broken glass.6. Contaminated animal carcasses, body parts, and animal bedding 7. Miscellaneous Contaminated Wastes – these include: - Wastes from surgery and autopsy - Miscellaneous laboratory wastes - Dialysis unit wastes - Contaminated equipment

INFECTIOUS WASTE MANAGEMENT PLANS

Components of an Infectious Waste Management Plan: 1. Designation of the waste that should be managed as infectious 2. Segregation of infectious waste from the noninfectious waste3. Packaging4. Storage5. Treatment6. Disposal7. Contingency measures for emergency situations 8. Staff training

DESIGNATION OF AN INFECTIOUS WASTE

The infectious waste plan for your facility should specify which wastes are to be managed as infectious wastes. The previous slides in this course can help determine what should be included. A responsible official or committee should determine any other miscellaneous wastes should be handled as an infectious waste.

SEGREGATING MEDICAL WASTES

Segregation of infectious wastes at the point of origin. Segregation of infectious waste with multiple hazards as necessary for management and treatment. Use of distinctive, clearly marked containers or plastic bags for infectious wastes. Use of the universal biological hazard symbol on infectious waste containers as appropriate.

SEGREGATING MEDICAL WASTES

Whenever possible, do not combine medical waste with hazardous chemicals or radioactive waste. Separate sharps waste from other medical wastes. Sharps should be stored in puncture-proof containers. Separate pathology wastes from other medical wastes. Separate chemotherapy wastes from other medical wastes.

SEGREGATING MEDICAL WASTES

If different types of waste are mixed, treat mixtures as follows: Mixtures of medical and radioactive waste --decontaminate the biohazardous component and manage as radioactive waste. Mixtures of medical and hazardous chemical waste -- if safe to do so, decontaminate the biohazardous component and manage as chemical waste. Mixtures of medical, radioactive, and hazardous chemical waste -- if safe to do so, decontaminate the biohazardous component and manage as radioactive waste.

PACKAGING INFECTIOUS WASTE

Selection of packaging materials that are appropriate for the type of waste handled:

- Plastic bags for many types of solid or semisolid infectious waste. - Bottles, flasks, or tanks for liquids. Use of packaging that maintains its integrity during storage and transport, Closing the top of each bag by folding or tying as appropriate for the treatment or transport Place liquid wastes in capped/ tightly stopped bottles. Do not compact infectious wastes before treatment.

Medical Waste• In any area that produces hazardous waste (such as hospital wards, treatment rooms, operating theatres, laboratories, etc.) five bins should be provided:

– Black: Non risk waste

–Red: Risk waste with sharp

–Blue: Risk waste without sharp

–Yellow: Radioactive waste

–Green: Chemical like Mercury and Cadmium

Medical Waste Segregation & Classification

HANDLING SHARPS

Each year there are some 600,000 incidents where people are accidentally stuck by needles and sharps. The most common times of risk for spreading bloodborne pathogens occurs:

– Recapping needles – Failing to dispose of used needles properly in puncture-

resistant sharps containers – Accidental breakage of the tubes used for collection of blood

in a variety of health care settings. There are an estimated 2,800 injuries from these glass capillary tube breakage every year.

HANDLING SHARPS

To protect against needlestick injuries, take the following precautions: Avoid the use of needles where safe and effective alternatives are available. Help your employer select and evaluate devices with safety features that reduce the risk of needlestick injury. Use devices with safety features provided by your employer. Avoid recapping needles. Plan for safe handling and disposal of needles before using them.

HANDLING SHARPS

Promptly dispose of used needles in appropriate sharps disposal containers. Report all needlestick and sharps-related injuries promptly to ensure that you receive appropriate followup care. Tell your employer about any needlestick hazards you observe. Participate in training related to infection prevention. Get a hepatitis B vaccination.

PACKAGING OF SHARPS

Containers are rigid puncture-resistant containers that, when sealed, are leak resistant and cannot be reopened without great difficulty. Must be red in color, have a biohazard label, be accessible to employees, and be located as close as feasible to the immediate area where sharps are used. Must remain upright throughout use and be replaced routinely. Should not be overfilled to present a hazard. Containers of contaminated sharps will be closed immediately. Secondary containers must be closable and prevent leakage during handling, storage, transport, or shipping.

STORAGE

Storage temperature and duration are important considerations. Warmer temperatures cause higher rates of microbial growth and putrefaction, resulting in odor problems. EPA recommends: Locating the storage area near the treatment site. Minimizing storage time. Proper packing that ensures containment of infectious waste and the exclusion of rodents and vermin. Limited access to storage areas. Prominently displaying the universal biological hazard symbol on storage area door, waste containers, etc.

TRANSPORT

Avoidance of mechanical loading devices that may rupture packaged wastes. Frequent disinfection of carts used to transfer wastes within the facility. Placement of all infectious waste into rigid or semi-rigid containers before transport off site. Transport of infectious waste in closed leakproof trucks or dumpsters. Use of appropriate hazard symbols in accordance with local, state and federal regulations.

MEDICAL WASTE HAULING

There are three methods for transporting regulated medical waste, including sharps, to a permitted regulated medical waste treatment or storage facility. 1. By a healthcare professional employed by the facility. 2. By contract with a transporter registered with the state.3. By mail, parcel post, or courier service (sharps only).

ON-SITE TREATMENT

There are several methods that have been successful in the treatment of infectious waste on-site. These include:

1. Autoclaving (steam sterilization)2. Incineration3. Thermal inactivation4. Gas/Vapor Sterilization5. Chemical Disinfection6. Sterilization by irradiation (radiofrequency and microwave)

AUTOCLAVING

Autoclaving (heating under high pressure) is widely accepted as an effective medical waste treatment technology. Steam sterilization, autoclaving, involves the use of saturated steam within a pressure vessel at temperatures high enough to kill infectious agents in the waste. Sterilization is accomplished primarily by steam penetration. Steam sterilization is most effective with low-density material such as plastics, metal pans, bottles, and flasks. High-density polyethylene and polypropylene plastic should not be used in this process because they do not facilitate steam penetration to the waste load.

AUTOCLAVING

Plastic bags should be placed in a rigid container before steam treatment to prevent spillage and drain clogging. Bags should be opened and caps and stoppers should be loosened immediately before they are place in the steam sterilizer. Care should be taken to separate infectious wastes from other hazardous wastes. Infectious waste that contains noninfectious hazards should not be steam-sterilized. Waste that contains antineoplastic drugs, toxic chemicals, or chemicals that would be volatilized by steam should not be steam-sterilized.

AUTOCLAVING

Persons involved in steam sterilizing should be trained in handling techniques to minimize exposure to hazards from these wastes. These should include: •Use of protective equipment •Minimization of aerosol formation •Prevention of spillage during autoclave loading/unloading •Prevention of burns from handling hot containers•Management of spills Check autoclave temperature to ensure that the proper temperature is being maintained for a long enough period during the cycle. Steam sterilizers should be routinely inspected.

INCINERATIONIncineration, complete combustion by exposure of the waste to intense heat, has been used for several years to treat and destroy medical wastesNewly Regulated Emissions from Medical Waste Incineration: 1. Particulate Matter2. Carbon Monoxide3. Dioxin4. Sulfur Dioxide5. Hydrogen Chloride6. Nitrogen Oxides7. Cadmium8. Lead9. Mercury

THERMAL INACTIVATION

Thermal inactivation involves the treatment of waste with high temperatures to eliminate infectious agents. This method is usually used for large volumes. Liquid waste is collected in a vessel and heated by heat exchangers or a steam jacket surround the vessel. The types of pathogens in the waste determine the temperature and duration of treatment. After treatment, the contents can be discharged into the sanitary sewer in a manner that complies with State, Federal, and local requirements. This method requires higher temperatures and longer treatment cycles than steam treatment.

GAS/VAPOR STERILIZATION

Gas/vapor sterilization uses gaseous or vaporized chemicals as the sterilizing agents. Ethylene oxide is the most commonly used agent, but should be used with caution since it is a suspected human carcinogen. Because ethylene oxide may be adsorbed on the surface of treated materials, the potential exists for worker exposure when sterilized materials are handled.

CHEMICAL DISINFECTION

Chemical disinfection is the preferred treatment for liquid infectious wastes. Consider the following:

– Type of microorganism – Degree of contamination – Amount of proteinaceous material present – Type of disinfectant – Contact time – Other relevant factors such as temperature, pH, mixing

requirements, and the biology of the microorganism Ultimate disposal of chemically treated waste should be in accordance with State and local requirements.

STERILIZATION BY IRRADIATION

Advantages of irradiation: Electricity requirements are nominal. Steam is not required. No heat or chemicals remain the treated waste.The principal disadvantages are as follows: Capital costs are high. Highly trained personnel are required. Space requirements are great. Worker exposure as a result of leaks in seals or poor work practices. Disposal of the radiation source may pose problems.

RADIOFREQUENCY IRRADIATION

Large radiofrequency irradiation medical waste treatment units include an initial destruction phase. The waste is automatically fed into a waste grinding device where it is shredded and sprayed with steam to increase the moisture content of the waste to approximately 10 percent. The moist ground waste is then heated by exposure to radiofrequency irradiation. This process heats the waste to >90 C. The factors which affect radiofrequency irradiation treatment of medical waste include the frequency and wavelength of the irradiation, the duration of the exposure, destruction and moisture content of the waste material, temperature achieved throughout the waste load during treatment, and waste storage duration.

MICROWAVE IRRADIATION

Large microwave irradiation medical waste treatment units include an initial destruction phase. The waste is automatically fed into a waste grinding device where it is shredded and sprayed with steam to increase the moisture content of the waste to approximately 10 percent. The moist ground waste is then heated by exposure to six microwave irradiation units over a 2 hour period. This process heats the waste to > 90 C. The factors which affect microwave treatment of medical waste include the frequency and wavelength of the irradiation, the duration of the exposure, destruction and moisture content of the waste material, process temperature, and the mixing of waste during treatment.

DRAIN DISPOSAL

Some liquid medical wastes, such as human blood, may be disposed of in sinks if the waste is first autoclaved or brought to a final concentration of 1 percent bleach. The following medical wastes may not be drain disposed: •Human or animal cultures suspected of containing infectious agents •Cultures and stocks of infectious agents •Wastes from the production of infectious bacteria, viruses, spores, discarded live and attenuated vaccines Non-infectious medical waste disposal should only be made to sanitary sewers only.

DISPOSAL OF TREATED WASTE

Infectious waste that has been effectively treated is no longer biologically hazardous and may be mixed with the disposed of as ordinary solid waste, provided the waste does not pose other hazards that are subject to federal or state regulations. EPA recommends:

– Contacting state and local governments to identify approved disposal options.

– Discharge of treated liquids and pathological wastes (after grinding) to the sanitary sewer system. Approval of the local sewer authority must be obtained.

CONTINGENCY PLANNING

The infectious waste management plan should include a contingency plan to provide for emergency situations. The plan should include, but not limited to, procedures to be used under the following circumstances: Spills of liquid infectious waste – cleanup procedures, Protection of personnel, and disposal of spill residue Rupture of plastic bags (or other loss of containment) – cleanup procedures, protection of personnel, and repackaging of waste Equipment failure – alternative arrangements for waste storage and treatment (e.g. offsite treatment).

DECONTAMINATION

All surfaces, tools, and other objects in contact with potentially infectious materials must be decontaminated and as soon as possible. Equipment and tools must be cleaned and decontaminated before servicing or being put back to use. Decontamination should be accomplished by using

– A solution of 5.25% sodium hypochlorite (household bleach / Clorox) diluted between 1:10 and 1:100 with water.

– Lysol or some other EPA-registered tuberculocidal disinfectant.

DECONTAMINATION

To clean up spilled blood, you can carefully cover the spill with paper towels or rags, then gently pour your 10% solution of bleach over the towels or rags, and leave it for at least 10 minutes. To decontaminate equipment or other objects (be it scalpels, microscope slides, broken glass, saw blades, tweezers, mechanical equipment upon which someone has been cut, first aid boxes, or whatever) you should leave your disinfectant in place for at least 10 minutes before continuing the cleaning process. Cleanup materials must be decontaminated.

STAFF TRAINING

Training should include an explanation of the infectious waste management plan and assignment of roles and responsibilities for implementation of the plan. Training programs should be implemented:

When the infectious waste management plan are first developed and instituted.

When new employees are hired, and When infectious waste management practices change.

Continuous education is also an important part of staff training.

ELEMENTS OF A SUCCESSFUL MEDICAL WASTE PROGRAM

1. DETAILED WRITTEN MEDICAL WASTE INSPECTION

GUIDELINES.

2. DETAILED WRITTEN MEDICAL BEST MANAGEMENT

PRACTICES.

3. EXTENSIVE EMPLOYEE TRAINING PROGRAMS

4. PERIODIC REINFORCEMENT OF TRAINING

5. SUFFICIENT DISCIPLINE REGARDING IMPLEMENTATION

6. PERIODIC FOLLOW-UP