Waste management has different purposes which may include:
· protect people who handle waste items from accidental injury,
· prevent the spread of infection to healthcare workers who handle the waste,
· prevent the spread of infection to the local community, and
· safely dispose of hazardous materials (toxic chemicals and radioactive compounds).
Waste can be classified into different groups such as combustible waste and non combustible waste, contaminated waste and non contaminated waste.
Combustible (burnable) wastes include paper, cardboard and contaminated wastes such as used dressings and gauze. Noncombustible (nonburnable) wastes include glass and metals. Wastes from hospitals and healthcare facilities may be contaminated (potentially infectious) or noncontaminated. Approximately 85% of the general waste produced by hospitals and clinics is noncontaminated waste and poses no infectious risk to persons who handle it. Examples of noncontaminated waste include paper, trash, boxes, bottles, plastic containers and food. They can be disposed of by the usual methods or sent to the local landfill or dumpsite (CDC 1985; Rutala 1993).
Some waste from healthcare facilities, however, is contaminated. If not disposed of properly, contaminated wastes may carry microorganisms that can infect the people who come in contact with the waste as well as the community at large. Contaminated wastes include blood, pus, urine, stool and other body fluids, as well as items that come in contact with them, such as used dressings. Wastes from operating rooms (human tissue, blood or blood soaked sponges, gauze or cotton) and laboratories (blood, feces, sputum, urine specimens and microbiological cultures) should be considered contaminated. Soiled medical devices or items that can inflict injury (e.g., used needles and scalpel blades) are capable of spreading bloodborne diseases such as hepatitis B, hepatitis C and AIDS, and are also considered contaminated waste.
Other types of waste that do not contain infectious agents, but are considered hazardous because of the potential harm they can cause to the environment include:
Ø chemical and pharmaceutical residues (e.g., cans, bottles or boxes containing expired drugs and vaccines, laboratory reagents and disinfectants such as formaldehyde and glutaraldehydes, and organic solvents such as acetone and chloroform);
Ø cytotoxic waste (e.g., drugs typically used in cancer chemotherapy);
Ø waste with a high content of heavy metals (e.g., mercury from broken thermometers, blood pressure gauges or dentistry materials, and cadmium from discarded batteries); and
Ø nonrecyclable and discarded pressurized containers (spray cans), that are hazardous if burned because they can explode.
Because of the risk that waste posed on the environment, different ways of disposals have been developed to enable a sustainable environment for all. Few among the many disposal methods are:
Encapsulation: is recommended as the easiest way to safely dispose of sharps. Sharps are collected in puncture-resistant and leakproof containers. When the container is three-quarters full, a material such as cement (mortar), plastic foam or clay is poured into the container until completely filled. After the material has hardened, the container is sealed and may be landfilled, stored or buried. It is also possible to encapsulate chemical or pharmaceutical waste together with sharps (WHO 1999).
Sanitary landfill: Engineered method of disposing of solid waste on land in a manner that protects the environment (e.g., by spreading the waste in thin layers, compacting it to the smallest practical volume and then covering it with soil at the end of each working day).
Incineration: is a high-temperature process that reduces the volume and weight of waste. This process is usually selected to treat waste that can not be recycled, reused or disposed of in a sanitary landfill or dumpsite.
Types of Incinerator can range from extremely sophisticated, high-temperature ones to very basic units that operate at much lower temperatures. All types of incinerators, if operated properly, eliminate microorganisms from waste and reduce the waste to ashes.
Four basic types of incinerators are used for treating waste:
1. Double-chamber, high-temperature incinerators are designed to burn infectious waste.
2. Single-chamber, high-temperature incinerators are less expensive and are used when double-chamber incinerators are not affordable.
3. Rotary kilns operate at high temperatures and are used for destroying cytotoxic substances and heat-resistant chemicals.
4. Drum or brick (clay) incinerators operate at lower temperatures and are less effective, but can be made locally using readily available materials.
Types of Waste That Should Not Be Incinerated
· Pressurized gas containers (aerosol cans)
· Large amounts of reactive chemical waste
· Silver salts and photographic or radiographic wastes
· Plastic containing polyvinyl chloride (blood bags, IV tubing or disposable syringes)
· Waste with high mercury or cadmium content, such as broken thermometers, used batteries and lead-lined wooden panels.
Adapted from: WHO 1999
Open piles of waste should be avoided because they:
· are a risk to those who scavenge and unknowingly reuse contaminated items,
· allow persons to accidentally step on sharp items and injure themselves,
· produce foul odors, and
· attract insects and animals.
In summary, we should be environmentally conscious and avoid buying or using chemical products or other products that can create impossible or very expensive disposal problems wherever possible.
References:
ü Centers for Disease Control (CDC). 1985. Recommendations for preventing transmission of infection with human T-lymphotropic virus type III/lymphadenopathy-associated virus in the workplace. MMWR34(45): 681–686; 691–695.
ü World Health Organization (WHO). 1999. Safe Management of Wastes from Healthcare Activities. WHO: Geneva.
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