Waste produced in the healthcare sector may in significant part be considered
as the hazardous waste. The health and environmental risks caused by this waste
can be well defined and conditions for its management can be clearly separated
from those of the waste generated in other areas.
According to the position statement by the United Nations’ World Health
Organization (WHO), in 2000 improper treatment of medical waste (primarily the
use of infected hypodermic needles and syringes) caused the following infections
- Hepatitis B: 21 million infections;
- Hepatitis C: 2 million infections; and
- HIV: 260,000 infections.
The above figures show that how relevant appropriate medical waste treatment is.
According to the WHO directive, hazardous waste should be processed as near to
its place of generation as is possible. The risks involved in the transportation
of hazardous waste are very large and risk factor found in some materials (e.g.
those that are infectious) increases daily. Suitably located and equipped waste
disposal facilities can minimize the need to transport the hazardous materials.
A lot of waste from hospitals is infectious biological material or objects,
which although they are considered communal waste, are in fact contaminated.
These latter items include textiles, bandages, syringes, and other objects
exposed to infection through contact with the patients. Very much of the waste
from hospitals is made up of special surgical instruments, such as the surgical
implants and other implements employed during operations. The disposal of
medical waste poses numerous questions, first of which is: How can medical waste
Types Of Biomedical Waste
There are following types of biomedical waste:
- Infectious waste:
Infectious waste is that which is suspected of containing pathogens (bacteria,
viruses, parasites, or fungi) in a sufficiently large quantity or concentration
to result in disease which are in susceptible hosts.
This category includes:
Cultures and stocks of infectious agents from the laboratories;
waste from operations and autopsies on the patients with infectious diseases
(e.g. body tissues, and materials or instruments having come into contact with
blood or other body fluids);
Waste originating from the infected patients in isolation wards (e.g. feces and
urine, dressings from infected or surgical wounds, clothing that is heavily
soiled with blood or other body fluids);
waste having come into contact with the infected haemodialysis patients (e.g.
dialysis equipment such as tubing and filters, disposable towels, gloves,
aprons, laboratory coats, and gowns);
And infected animals from laboratories.
- Pathological waste
Infectious materials containing dead tissue may conceal especially the dangerous
and/or communicable infectious agents. Such waste includes blood, body fluids,
tissues, organs, body parts, human foetuses, and animal carcasses. A subcategory
of pathological waste is anatomical waste, which consists of the identifiable
human or animal body parts, healthy or otherwise.
Sharps are the objects sharp enough to cut or puncture the skin, e.g. knives,
scalpels and other blades, infusion sets, needles, hypodermic needles, saws,
broken glass, nails, etc. They can transmit infections directly into
bloodstream. Sharps are treated as highly hazardous medical waste regardless of
whether they are contaminated or not.
Regarding sharp waste, special consideration must necessarily be paid to:
infusion, transfusion, and perfusion sets; butterfly needles; cannulas;
disposable scalpel blades and razors; hemodialysis sets; laboratory slides;
broken glass containers (bacteriological and clinical laboratories); ampoules
containing solution residues, etc.
How does biomedical waste impact environment?
Improper segregation of biomedical waste and different medical waste streams
from the point of origin can trigger a domino-like effect on environment that
incurs dangers to people, animals, or soil and water sources.
Improper segregation and disposal of biomedical waste has the potential to
contaminate groundwater sources, which in turn may infect the humans and animals
alike. From a hospital’s waste and storage receptacles to the landfills,
biomedical waste needs to be properly contained to keep it away from birds,
rodents, and stray animals (as well as humans). This enhances packaging and
labeling of the contaminants and helps prevent the spread of illness through
human and animal populations – by air, land, or water.
If not properly contained, segregated, and incinerated through on-site or
off-site incineration, environmental hazards associated with improper healthcare
waste management can contaminate air we breathe through dangerous airborne
particles. A radioactive particle produced with diagnostic technologies has the
potential to reach a landfill or other areas of the environment, especially air.
Air pollutants disseminated over huge areas of inhabited land have potential to
trigger a number of illnesses.
Improper disposal of biomedical waste may cause negative impact on the water
quality as different pollutants may leach out from the waste dumping sites into
the ground water. Al Raisi et al. (2014) assessed and found that the heavy
metals in leachate were exceeding the drinking water standards. The
concentrations of the Al, V, Cr, Mn, Co, Ni, Ba, Pb, and Fe 2.050, 0.9775,
2.800, 0.503,0.128, 0.773, 0.8575, 0.130, and 39.25 mg/L, respectively. The
effect of these contaminants was considered as the surface and ground water
Improper and unscientific disposal of biomedical waste may change the quality of
soil near the waste dumping sites. Different pollutants may get mixed with soil
and may change the chemistry and biology of the soil ecosystem. Abidemi and
Theresa (2015) analyzed five heavy metals (chromium, nickel, zinc, lead, and
copper) for their levels in the soil. The concentration of the heavy metals in
soil were zinc (1133 ± 897 mg/kg), nickel (26.3 ± 51.1 mg/kg), copper
(110 ± 90 mg/kg), lead (137 ± 64 mg/kg), and chromium (3.63 ± 2.46 mg/kg). The
level of heavy metals at different sampling site were higher than the soils from
background with factors of 67 (zinc), 18 (copper), and 20 (lead).
Medical hazardous waste disposal and treatment technologies
Certain treatment solutions that diminish the risks of infection from medical
waste and preclude scavenging may even cause other health and environmental
hazards. Incineration of certain kinds of medical waste, particularly those
which contain heavy metals or chlorine, may release toxic substances into the
atmosphere (due to, for example, insufficiently high incineration temperatures
or the inadequate control of emissions).
Disposal of waste by burial in landfill may cause the pollution of groundwater
(if the site is inappropriately designed and/or managed). Because of the
aforementioned hazards, when a treatment or disposal solution for medical waste
is selected (especially when there is a risk of toxic emissions or other
dangerous consequences), relative risks and the integration of the method into
the overall framework of a comprehensive waste strategy should be carefully
evaluated taking local conditions into consideration.
Various technologies for medical waste disposal are:
Incineration was formerly the most popular method of disposing of the majority
of the hazardous medical waste. Although it remains a widely-used solution,
alternative methods are also growing in popularity. When selecting a treatment
solution, various factors must be taken into consideration and many of these
depend on the local conditions, such as health and safety requirements, and the
available options for the final disposal of the waste, etc.
The effectiveness of incineration is beyond doubt, yet this method entails
serious issues concerning air quality. Due to the fact that reagent is
atmospheric oxygen, a large volume of air shall continuously pass through the
system. If exhaust air does not pass through a control device, all substances
that are volatile at the system’s operating temperature will be emitted with the
The disadvantages of incinerators are:
- Investment and operating costs are high.
- The cytotoxics are not completely destroyed.
- The emissions of the atmospheric pollutants are significant.
- The periodic removal of the slag and the soot is necessary.
- Destruction of thermally-resistant chemicals and drugs such as cytotoxics is inefficient.
- Only 99% of the microorganisms are destroyed.
- Simple chemical disinfection processes
Chemical disinfection has an extensive role in healthcare, being used to
eliminate the microorganisms on medical equipment, and on walls and floors.
Nowadays chemical disinfection process is also used to treat medical waste. The
addition of chemicals to the waste destroys or deactivates the pathogens in it,
although the result is more frequently disinfection rather than the
sterilization. This solution is most appropriate for the treatment of the liquid
waste including blood, liquid excreta, or hospital sewage.
In spite of this
fact, the solid (and even highly hazardous) medical waste materials, such as
microbiological cultures, sharps, etc., can also be chemically disinfected. The
aforementioned process has the following drawbacks:
The efficiency of disinfection is dependent on the operational conditions.
Chemical disinfection is typically performed on site, i.e. within the hospital
itself. However there is a growing tendency for the development of commercial,
self-contained, and fully automatic systems for medical waste treatment located
in the industrial zones. The processed waste can be disposed of as non-risk
medical waste, but if the chemical disinfectants used leak or are improperly
disposed of, they may have a detrimental impact on environment.
The disadvantages of chemical disinfection are:
- Hazardous substances that require the comprehensive safety measures are
- In cases of pharmaceutical, chemical, and some types of infectious
waste, it is inadequate.
- If chemical disinfectants are costly, the process is made expensive.
- Ozone is an effective sterilizer in a medical waste treatment system and
it does not generate any by-products to be encountered when using chlorine
compounds. However, since ozone is greatly damaging to the lungs, steps must
be taken to ensure that those in the vicinity of the system are not exposed
to this gas.
- Other agents utilized for chemical treatment of the medical waste are
alkalis, either highly corrosive ones (sodium hydroxide or lye), or in
milder forms (calcium oxide or quicklime). Among the other effects, alkalis
have the tendency to hydrolyze proteins. If the expense of the reagents is
disregarded, the main disadvantage of this method is the risk of contact, as
alkaline solutions are injurious to the skin and the lungs.
- Wet thermal treatment (steam sterilization / autoclaving)
In wet thermal treatment, the waste is first shredded and then exposed to very
high-pressure, high-temperature steam. It has some similarities to the process
of autoclave sterilization. Given a suitable temperature and contact time, most
varieties of the microorganism are inactivated by wet thermal disinfection (for
example for sporulated bacteria, the minimum necessary temperature is 121°C).
In order to increase the efficiency of the disinfection, sharps should be
crushed or milled. This solution is unsuitable for the treatment of anatomical
waste and animal carcasses and is inefficient when processing the chemical or
The disadvantages of wet thermal treatment are:
- Operational conditions have a pronounced influence on the efficiency of
- An inadequate shredder may retard the efficiency.
- It is unsuitable for the treatment of the anatomical, pharmaceutical,
and chemical waste and also for waste materials that do not easily permit
the penetration of steam.
- Land disposal
Land disposal is considered to be an acceptable solution when there is no means
of treating the waste prior to its disposal. If hazardous and untreated medical
waste accumulates at hospitals, for example, a far greater risk of infections
being transmitted is posed than if the waste is carefully disposed of at the
landfill site. Objections to this method may be religious or cultural, or they
may even be based on a perceived risk of the escape of pathogens into the air,
soil, and water, or on the dangers entailed by scavengers having access to the
Due to the unorganized and scattered deposit of the waste at open dumps, there
may be serious pollution issues, fires, a heightened risk of disease
transmission, and ingress by human and animal scavengers. Medical waste must
never be disposed of on or in the vicinity of the open dumps. The dangers of
people or animals coming into contact with active pathogens are exacerbated by
the additional risk of the subsequent transmission of infections, either
directly via wounds, inhalation, or ingestion, or indirectly via the pathogenic
host species or the food chain.
Sanitary landfill sites are preferable to the open dumps considering at least
four points: they geologically isolate waste materials from the environment;
engineering specifications for the acceptance of waste are met; operations are
directed by on-site personnel; waste-deposit is organized and the wastes are
covered over daily. The disposal of some of the medical waste (infectious waste
and pharmaceutical waste in small amounts) is acceptable.
Medical waste disposal: the WHO's recommendation
Waste generated by the healthcare activities includes a broad range of
materials, from used needles and syringes to soiled dressings, body parts,
diagnostic samples, blood, chemicals, pharmaceuticals, medical devices, and
Poor management of the medical waste potentially exposes healthcare workers,
waste handlers, patients and the community at large to infection, toxic effects
and injuries, and risks polluting the environment. It is essential that all the
medical waste materials are segregated at the point of generation, appropriately
treated, and disposed of safely.
Management of the biomedical waste is linked with risks to people who are
directly and indirectly associated with this profession. Biomedical waste has
caused the challenge to maintain the quality of water, air, and soil. The
quantities and proportions of different constituents of the wastes, their
handling, treatment, and disposal methods in different healthcare settings
varies and treatment and disposal methods have been found to be inadequate in
most of the studies.
Hazards associated with the poor biomedical waste management and shortcomings in
the existing system have been identified by various researchers. The development
of the waste management policies, plans, and protocols were recommended in most
of the studies. Moreover, establishing training programs on proper waste
management for all the healthcare workers was established. Research to convert
the biomedical waste into energy and other useful products need to be explored.
This will be helpful to prevent environmental contamination and the health risk