Medical Waste Management and Control

Abstract

Medical centers including hospitals, clinics and places where diagnosis and treatment are conducted generate wastes that are highly hazardous and put people under risk of fatal diseases. Although the understanding of medical waste management and control techniques is important, technical elective courses that are offered in undergraduate chemical, civil or environmental engineering place less emphasis on this area of education. In this paper, the meaning of medical waste, the risks of exposure, medical waste management regulatory acts, medical waste management procedures and control techniques are presented. The contents presented in this paper served as a supplementary material in an under-graduate elective course on waste management and as an educational guide for medical staff training on waste handling.

Full text

Journal of Environmental Protection, 2012, 3, 1625-1628
doi:10.4236/jep.2012.312179 Published Online December 2012 (http://www.SciRP.org/journal/jep) 1625
Medical Waste Management and Control
Zarook M. Shareefdeen
American University of Sharjah, Sharjah, UAE.
Email: zshareefdeen@aus.edu
Received August 22nd, 2012; revised September 19th, 2012; accepted October 21st, 2012
ABSTRACT
Medical centers including hospitals, clinics and places where diagnosis and treatment are conducted generate wastes
that are highly hazardous and put people under risk of fatal diseases. Although the understanding of medical waste
management and control techniques is important, technical elective courses that are offered in undergraduate chemical,
civil or environmental engineering place less emphasis on this area of education. In this paper, the meaning of medical
waste, the risks of exposure, medical waste management regulatory acts, medical waste management procedures and
control techniques are presented. The contents presented in this paper served as a supplementary material in an under-
graduate elective course on waste management and as an educational guide for medical staff training on waste handling.
Keywords: Medical Waste; Medical Waste Act; Waste Management and Control
1. Introduction
Waste in general is any substance (solid, liquid, or gas)
that has no direct use and is discarded permanently. A
waste is considered hazardous if it exhibits any of the
characteristics such as being flammable, reactive, explo-
sive, corrosive, radioactive, infectious, irritating, sensi-ti-
zing, or bio-accumulative [1]. Medical waste is limited to
infectious, hazardous, and any other wastes that are gen-
erated from health care institutions, such as hospitals,
clinics, dental offices, and medical laboratories [2]. The
management of medical waste has been of major concern
due to potentially high risks to human health and the en-
vironment. In the past, medical wastes were often mixed
with household wastes and disposed in municipal solid
waste landfills.
Hassan et al., 2008 [3] report a survey on Bangladesh
hospitals that generate a total of 5562 kg/day of wastes,
of which about 77.4% are non-hazardous and about
22.6% are hazardous. The average waste generation rate
for the surveyed hospital is 1.9 kg/bed/day or 0.5 kg/pa-
tient/day. The study reveals that there is no proper, sys-
tematic management of medical wastes except in a few
private hospitals that segregate their infectious wastes.
Some cleaners were found to salvage used sharps, saline
bags, blood bags and test tubes for resale or reuse. In
Bangladesh, proper medical waste management is a new
phenomenon and government of Bangladesh is trying to
develop a new and modern approach to deal with the
medical waste properly. Project in Agriculture, Rural In-
dustry, Science and Medicine (PRISM-Bangladesh), a
reputed national NGO in Bangladesh, with the financial
support from Canadian International Development Agency
(CIDA) has recently developed a disposal facility for low
cost medical waste treatment and management in Dhaka
City.
Similarly, the generation of medical waste in Korea
has been increasing in quantity and variety, due to the
wide acceptance of single-use disposable items (e.g.
gloves, plastic syringes, medical packages, bedding, tub-
ing, and containers) [4]. In recent years, increased public
concerns over the improper disposal of medical waste
have led to a movement to regulate the waste more sys-
tematically and stringently by the Korea Ministry of En-
vironment. Waste minimization and recycling are still
not practiced, thus significant amounts of medical wastes
are to be disposed. Incineration is the main method of
medical waste treatment in Korea.
In the United Arab Emirates (UAE), there are over 800
clinics and hospitals that generate hazardous medical
wastes [5,6]. The main method of medical waste treat-
ment in most countries of the Middle East is incineration;
however, other techniques that produce less pollution are
now being introduced. The literature shows numerous
case studies on the mismanagement of medical wastes as
described above for illustration purpose.
The objective of this paper is to introduce readers
about the medical waste management regulatory acts,
definition of medical wastes, risks of exposure, medical
waste management procedures and control techniques.
2. Medical Waste Tracking Act and
Definitions
The Medical Waste Tracking Act (MWTA, 1988) is the
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Medical Waste Management and Control
1626
first act to regulate medical wastes [7]. It was imple-
mented after life-threatening incidents occurred due to
the lack of proper medical waste disposal systems. One
example of such incident was on June 1987 when 12
children in Indianapolis, Indiana, played with vials they
found in a dumpster outside a medical office. The vials
were filled with blood, and two of them were infected
with AIDS. After medical wastes were found washing up
on several East Coast beaches, USEPA (US Environ-
mental Protection Agency) prompted US Congress to
enact the MWTA in 1988 [8]. The Act required EPA to
create a two-year medical waste demonstration program.
For the purpose of the demonstration program, the
MWTA: a) defined medical waste and those wastes to be
regulated; b) established a cradle to grave tracking sys-
tem utilizing a generator initiated tracking form; c) re-
quired management standards for segregation, packaging,
labeling and marking, and storage of the waste; and d)
established record keeping requirements and penalties
that could be imposed for mismanagement. According to
MWTA medical waste is “any solid waste that is gener-
ated in the diagnosis, treatment, or immunization of hu-
man beings or animals, in research, or in the production
or testing of biologicals” [8,9].
The World Health Organization (WHO) has classified
medical waste into different types: a) Infectious: mate-
rial-containing pathogens in concentrations high enough
to cause diseases on exposure. This includes waste from
surgery, lab cultures, used dressings, and others. b)
Sharps: disposable needles, syringes, blades, broken
glasses. c) Pathological: tissues, organs, body parts, hu-
man flesh, blood and body fluids. d) Pharmaceuticals:
drugs and chemicals that are returned, spilled, expired or
contaminated. e) Chemical: waste resulting from diagno-
sis, or cleaning material. f) Radioactive: waste contami-
nated with radioactive substances used in diagnosis and
treatment of diseases. g) Pressurized containers including
gas cylinders and h) Substances with high heavy metal
content: broken mercury thermometers, blood pressure
gauges. Infectious, pathological and sharps are the most
dominant types of medical waste [10].
The definition of medical waste excludes waste con-
taining microbiological cultures used in food processing,
urine, saliva, and nasal secretions unless they contain
blood. Like any household and office, medical facilities
also generate general wastes such as paper and plastic
that are not dangerous to human beings [9]. Medical
waste such as sharps (i.e. needles, syringes, scalpels, etc.)
can endanger human in a non-infectious way.
Depending on the institutions, the quantities of medi-
cal wastes produced vary [11]. Households are consid-
ered to be small quantity generators, while hospitals are
considered to be large quantity generators (>100 kg/
month or more of medical waste). Medical wastes in-
cluding infectious and sharp wastes account for about
35% of the total waste generated in hospitals. The re-
maining 65% of the wastes are non-infectious. Unlike
industrial wastes which vary depending on the type of
processes or sectors (i.e. chemical, petroleum, municipal
etc.), medical waste compositions remain more or less
the same.
Regardless of its quantity and where it is generated,
medical waste has serious sometimes fatal effects on
exposure. Medical staff, janitors, medical center visitors
and patients are exposed to the risk of infection and dis-
eases as a result of exposure. Thus, medical waste haz-
ards and risks exist not only for the waste generators and
operators, but also for the general community including
children who play near disposal areas. The possible ex-
posure pathways include direct contact, airborne trans-
mission, contaminated water sources and the environ-
ment in general.
3. Medical Waste Management Techniques
There are several methods to minimize the hazards re-
sulting from medical waste [10].
3.1. Segregation
Segregation is useful since it prevents the contamination
of non-hazardous waste by the hazardous waste and
making the whole waste stream hazardous. Thus, this
method will reduce the toxicity and the volume of the
waste stream. Moreover, segregation makes it easier to
transport the waste. Waste is segregated depending on
the quantity, composition, and the disposal method of the
waste stream.
3.2. Separating Different Categories of Medical
Wastes
In medical centers, infectious and pathological waste,
and sharps are placed in different containers. The con-
tainers are labeled as “biohazard”, closed, water tight and
of uniform color for each type of medical waste through-
out the medical center. The size of the containers de-
pends on the volume of waste generated and the contain-
ers used are easy to handle and transport. For used nee-
dles specially designed containers are used.
The system for segregation, packaging, labeling and
marking involves separating the medical waste into
categories, as described. The packaging is done in col-
ored bags [12]. For example, yellow plastic bags are used
for infectious medical waste that is meant to be disposed
by means of incineration or deep burial in landfill. How-
ever, if they are to be treated by autoclave or microwave,
they are placed in red plastic bags or containers. In steam
autoclaving, the waste is decontaminated by the effects
of the saturated steam at elevated temperatures and high
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Medical Waste Management and Control 1627
pressure. This method is not applicable for pathological,
chemotherapy and radioactive wastes.
Hazardous waste packaged in either blue or white
transparent bags is usually treated by autoclave, micro-
wave, chemical treatment and shredding, or by landfill-
ing. As for labeling and marking, medical wastes are
popularly known to have the bio-hazard symbol. Both the
packaging and labeling are adopted worldwide. The dif-
ference is in treatment methods [12].
3.3. Disinfection
In order to reduce the toxicity of some medical wastes,
chemical disinfectants (i.e. chlorine dioxide, sodium hy-
pochlorite, or per acetic acid) are sometimes used. For
solid wastes, disinfection is effective if only waste mate-
rials are shredded. In some cases, the disinfectants them-
selves are hazardous, thus it is not recommended for
treating pharmaceutical, chemical and some types of in-
fectious waste.
3.4. Incineration
Incineration is the process of destructing waste by burn-
ing it at elevated temperatures in furnaces. The process
removes hazardous materials, reduces the mass and
volume of the waste and converts it into ash that is
harmless. Incineration is suitable for wastes that are 60%
combustible. Incineration is suitable for pathological and
infectious waste or sharp wastes. Incinerators exist in
several different types; each type has a specific function.
A mobile incinerator called “drug terminator” is used for
disposal of pharmaceuticals. A diesel fired medical waste
incinerator called “MediBurn” treats pathological and
infectious waste in small medical facilities, and laborato-
ries [13]. This unit is portable and easy to operate and it
can incinerate everything from laboratory waste to ani-
mal remains.
The advantage of incineration process is that the vol-
ume of the waste that will remain for disposal will be
reduced by 50 - 400 times [14]. Incineration has a sig-
nificant advantage of decreasing the volume of the
wastes; however its disadvantages include high costs,
smoke generation and pollution risks. Incinerators used
in hospitals produce more furans and dioxins than incin-
erators used in municipality. This higher concentration of
furans and dioxins are due to a) frequent startups and
shutdowns b) less stringent emission controls c) poor
combustion control (e.g., waste mixing and oxygen con-
trols), and d) differences in the waste feed composition
as compared with municipal solid waste [15]. Incinera-
tors are usually built with a chimney to reduce the smoke
and its effect on pollution. Moreover, incinerators are
usually located at least 100 m away from the medical
center in order to reduce the effect of smoke. A pit below
the incinerator is usually available in order to collect the
ashes. Incineration is one of the most efficient methods
of disinfecting medical waste.
3.5. Disinfection by Plasma
In this process, low temperature plasma which is pro-
duced by the plasma generator using air as working fluid
organizes a combustion process. The medical waste is
constantly mixed, thus it maximizes the heat and mass
exchange which saves any energy loss. The heat pro-
duced is used as an additional heat source in the process.
This technology eliminates the formation and release of
irregular forms of NOX and high-toxic substances (i.e.
dioxins) into the atmosphere. Another main advantage is
that it has low consumption of energy compared to other
mineralization (i.e. combustion) processes [14].
3.6. Emerging Technology
A new technology for management of hazardous medical
waste that transforms the regulated medical waste into
municipal solid waste is recently introduced. This
method involves shredding and grinding the infectious
medical waste bags via sharp cutting blades that are in-
stalled within the vessels. The blades rotate around 1750
revolutions per minute and the volume of the shredded
waste is reduced by 80% [16]. The steps included in
the process are loading, shredding, heating, sterilization,
cooling, draining, vacuum and unloading. The whole
process is enclosed in a compact system and there is no
intermediate handling of the waste within the process.
Due to the compact size, this system can easily be used
for on-site treatment of the waste and installed in hospi-
tals. This will reduce the transportation costs of the
medical wastes. In terms of environmental aspects, it is a
clean and chemical-free technology and does not have
any hazardous emission or radiation [16]. This method is
economical and environmentally friendly and is reliable
in terms of ease of use and maintenance. This technology
is currently practiced in the middle-eastern countries
such as Iraq, Jordan, Kuwait, Lebanon, Syria and UAE.
Similarly, a team of engineers in Idaho National
Laboratory, USA have invented a new patented technol-
ogy that helps in better management and treatment of the
medical wastes. Based on this technology, Med-Shred,
Inc., (Texas, USA) has developed a mobile shredding
and chemical disinfecting machine that is aimed for
on-site treatment of hazardous medical waste [17]. The
machine converts the medical waste into disposable mu-
nicipal waste using shredders that shred the waste into
smaller particles which are then wetted with disinfectant
spray and immersed in a disinfection solution. The wet
waste is then dried using a hot off-gas in a drying cham-
ber. Considering the number of clinics and hospitals in
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Medical Waste Management and Control
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1628
middle-east, this method will be very successful if util-
ized, as it can treat the medical waste on-site which helps
in better management of wastes.
4. Conclusion
Medical wastes are highly hazardous and put people un-
der risk of fatal diseases. The understanding of medical
waste management and control techniques is important.
In this paper, introductory materials on the definition of
medical waste, medical waste management regulatory acts,
the risks of exposure, medical waste management proce-
dures and control techniques are presented.
5. Acknowledgements
The author acknowledges feedback of chemical engi-
neering students from the American University of Shar-
jah (AUS) and medical staff of Al-Qassimi Hospital,
Sharjah, UAE.
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