A vast amount of waste is generated in the process of healthcare, research, testing, or related procedures on human beings or animals conducted in hospitals, clinics, labs, or similar establishments. This waste is called biomedical waste. Due to the presence of a higher concentration of infectious and other such hazardous substances, this form of waste requires special attention for its safe disposal.
If the waste finds its way back to the community, the results would be disastrous to say the least. It can act as a source of infection to residents or visitors of hospitals, and the chemicals contained in the waste may seep into the surrounding soil and contaminate wells and tanks, thereby polluting them.
Types of Biomedical Waste
Handling of biomedical waste is increasingly associated with the risk of laboratory-acquired infections. Most of these infections include those caused by hepatitis B virus, Bacillus anthracis, Mycobacterium tuberculosis, Francisella tularensis, Shigella species, and Brucella species.
Biomedical wastes are of the following types:
Human anatomical waste: This consists of human tissues, organs, and body parts, but does not include teeth, hair, and nails.
Animal waste: This consists of all animal tissues, organs, body parts, carcasses, bedding, fluid, blood and blood products, items saturated or dripping with blood, body fluids contaminated with blood, and body fluids removed for diagnosis or removed during surgery, treatment, or autopsy. This excludes teeth, hair, nails, hooves, and feathers.
Microbiology laboratory waste: This consists of laboratory cultures, stocks or specimens of microorganisms, live or attenuated vaccines, and human or animal cell cultures used in research and laboratory material that have come into contact with any of these.
Human blood and body fluid waste: This consists of blood and blood products, items saturated or dripping with blood, human body fluids contaminated with blood, and body fluids removed for diagnosis during surgery, treatment, or autopsy. This does not include urine or feces.
Waste sharps: Waste sharps are clinical and laboratory materials consisting of needles, syringes, blades, or laboratory glass capable of causing punctures or cuts.
Cytotoxic waste: The term is commonly used to refer to pharmaceuticals used in treating cancer, e.g., antineoplastics or chemotherapy agents.
Waste Treatment Methods
Steam autoclaving: Steam autoclaving is an appropriate method for treating microbiology laboratory waste, human blood and body fluid waste (if applicable), waste sharps, and nonanatomical animal wastes. It must not be used for treating either human or animal anatomical waste.
Special emphasis is given to the type of plastic bags used in the autoclave. Some bags impede steam penetration, while others may melt during the autoclave cycle. Plastic bags, therefore, are assessed under actual working conditions to ensure their effectiveness and integrity throughout the autoclave cycle. Organic wastes containing oxidizing agents like sodium hypochlorite or solvents are not autoclaved due to their potential for explosion.
Chemical decontamination: Chemical decontamination is recommended for treating microbiology laboratory waste, human blood, and body fluid waste. It is not used for treating anatomical waste. Waste sharps may be chemically decontaminated; however, the sharps may not be completely sterilized unless mechanical shredding is involved. Shredding is only done where the shredder is integral to an incinerator, which is sealed to prevent any release.
Incineration: Incineration is a process in which combustible materials are converted into noncombustible residue or ash, achieving a reduction of 90% by volume or 75% by weight when the incinerator is properly operated. Incineration has traditionally been the principal method used by hospitals, medical colleges, and other healthcare facilities providers to process their anatomical and non-anatomical biomedical wastes. To date, incineration is the only disposal technology proven to be capable of handling all components of the biomedical waste stream.
Microwave treatment: Radiations produced by microwave are increasingly used nowadays for treatment of infectious hospital wastes. The microwaves heat the biological wastes to a temperature of 97–100°C in a 40–45 minutes cycle. The advantage of the method is that it is not associated with any hazardous emissions, but it cannot be used to treat anatomical body parts and tissues.
Plasma torch: Waste treatment by plasma torch produces a very high temperature that is very useful for treatment of biological wastes. It is a very safe method, although it is highly expensive.