TOPIC- HOSPITAL WASTE
MANAGEMENT
SUBMITTED BY: ASIYATH SHAHANA BADARUDEEN
SUBMITTED TO: DR.PRAMADA
DEPARTMENT OF PUBLIC HEALTH DENTISTRY
REG NO: 20D013
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CONTENTS
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INTRODUCTION
DISPOSAL OF SOLID WASTE
DISPOSAL OF HEALTH CARE WASTE
CONCLUSION
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INTRODUCTION
Waste management is the collection, transport, processing, recycling or disposal of
waste materials. The term usually relates to materials produced by human activity,
and is generally undertaken to reduce their effect on health, the environment or
aesthetics. Waste management can involve solid, liquid, gaseous or radioactive
substances, with different methods for each.
Solid waste
The term "solid wastes" includes
• garbage (food wastes)
• rubbish (paper; plastics, wood, metal, throw-away containers, glass)
• demolition products (bricks, masonry, pipes)
• sewage treatment residue (sludge and solids from the coarse screening of
domestic sewage)
• Dead animals
• Manure and other discarded material.
Strictly speaking it should not contain nightsoil.
Sewage:
Waste water from a community containing solid and liquid excreta, derived from
houses, street and yard washings, factories and industries.
Sullage:
Waste water which does not contain human excreta.
THE HEALTH HAZARD OF ACCUMULATED SOLID WASTE ARE,
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• it decomposes and favors fly breeding
• it attracts rodents and vermin
• The pathogens present in the solid waste may be conveyed back to man's
food through flies and dust.
• there is a possibility of water and soil pollution
• It is unaesthetic and produces bad odours.
Storage
The first consideration to be given is to the proper storage of refuse, while awaiting
collection. The dust bin should be large enough to cater to the requirements and
should have a close fitting cover.
Collection
Waste can be collected from each house, which is the best method of collecting
refuse. Another method is to have public bins in which waste can be collected.
Transport
Waste should be transported using enclosed vans to the area of disposal
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DISPOSAL OF SOLID WASTE
There is no single method of refuse disposal, which is equally suitable in all
circumstances. The principal methods of are,
• Dumping
• Controlled tipping or sanitary land-fill
• Incineration
• Composting
• Manure pits
• Burial
Dumping:
In this method, refuse is dumped in low lying areas. This is an easy method of
disposal of dry refuse and is also suitable for reclamation of land. As a result of
bacterial action, refuse decreases considerably in volume and is converted
gradually into humus.
The drawbacks of open dumping are:
• The refuse is exposed to flies and rodents
• It is a source of nuisance because of the smell and unsightly appearance
• The loose refuse is dispersed by the action of the wind
• Drainage from dumps contributes to the pollution of surface and ground
water.
It is considered as the most unsanitary method of waste disposal.
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Controlled tipping (sanitary landfill)
It is the most satisfactory method of refuse disposal where suitable land is
available. It this method, the material is placed in a trench or other prepared area,
adequately compacted, and covered with earth at the end of the working day.
Three methods are used in this operation, the trench method, the ramp method and
the area method.
The trench method: This method is used where level ground is available. A long
trench is dugout - 6-10 ft. deep and 12-36 ft. wide, depending upon local
conditions. The refuse is compacted and covered with excavated earth.
The ramp method: This method is used where the terrain is moderately sloping
Some excavation is done to secure the covering material.
The area method: This method is used for filling land depressions. The refuse is
deposited and sealed on its exposed surface with a mud cover. This method has the
disadvantage of requiring supplemental earth from outside sources.
Chemical, bacteriological and physical changes occur in the buried refuse. The
temperature rises to over 60°C within 7 days and kills all the pathogens and
hastens the decomposition process. It takes 4 to 6 months for complete
decomposition of organic matter into an innocuous mass
Incineration
Refuse can be disposed off hygienically by burning or incineration. Incineration
requires a preliminary separation of dust or ash from the refuse. Incineration
involves heavy outlay and expenditure, besides manipulative difficulties. Further,
disposal of refuse by burning is a loss to the community in terms of the much
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needed manure. Therefore, it has a limited application in refuse disposal and is
mainly used for health care waste disposal.
Composting
It is a process of nature where matter breaks down under bacterial action resulting
in the formation of a relatively stable humus-like material, called the compost
which has considerable manurial value for the soil. The principal by-products are
carbon dioxide, water and heat. The heat produced during composting 60°C or
higher, destroys all pathogenic agents. The compost formed contains few or no
disease producing organisms and is a good soil builder containing small amounts
of the major plant nutrients such as nitrates and phosphates. The methods of
composting are,
 Bangalore method (hot fermentation process)
This anaerobic method was developed by the Indian Council of Agricultural
Research at the Indian Institute of Science, Bangalore. Trenches are dug depending
upon the amount of refuse and nightsoil to be disposed off. Depths greater than 3 ft
are not recommended because of slow decomposition. The pits should be located at
least 800 m away from the city limits.First a layer of refuse is spread at the bottom
of the trench. Over this, nightsoil is added. Then alternate layers of refuse and
nightsoil are added till the heap rises 1 ft above the ground level. The top layer
should be of refuse, at least 9 inches in thickness. Then the heap is covered with
excavated earth and compacted. Within 7 days as a result of bacterial action
considerable heat (over 600C) is generated in the compost mass. The intense heat
which persists over 2 to 3 weeks, causes decomposition of the material. At the end
of 6 months, decomposition is complete and the resulting material is a well
decomposed, odourless, innocuous material with manurial value.
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 Mechanical composting
In this aerobic method, compost is, manufactured on a large scale. The refuse is
first cleared of salvageable materials such as rags, bones, metal, glass and other
items which are likely to interfere with the grinding operation. It is then pulverized
in a pulverizing equipment in order to reduce the size of particles to less than 2
inches. The pulverized refuse is then mixed with sewage, sludge or nightsoil in a
rotating machine and incubated. The entire process of composting is complete in 4
to 6 weeks.
Manure pits
They are dug by individual householders to dump the garbage, cattle dung, straw;
and leaves. They are covered with earth after each day's dumping. In 5 to 6 month's
time, the refuse is converted into manure which can be returned to the field. This
method of refuse disposal is effective and relatively simple in rural communities.
Burial
A trench is excavated, and at the end of each day the trench is filled with earth and
compacted. This method is suitable for small camps.
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DISPOSAL OF HEALTH CARE WASTE
Health care waste is defined as all the waste generated by health-care
establishments, research facilities and laboratories. In addition, it includes the
waste originating from 'minor' or "scattered" sources such as that produced in the
course of health care undertaken in the home (dialysis, insulin injection etc.).
Waste produced in the course of health care activities carries a higher potential for
infection and injury than any other types of waste. Inappropriate and inadequate
handling of health care waste may have serious public health consequences and a
significant impact on the environment.Wherever it is generated, safe and reliable
methods for its handling are therefore essential.
Categories of health care waste:
1. Infectious waste: Waste suspected to contain pathogens. Eg. Lab cultures,
equipment that have been in contact with infected patients.
2. Pathological waste: Human tissues or fluids. Eg. Body parts, blood
3. Sharps: Needles, blade
4. Pharmaceutical waste: Expired drugs
5. Genotoxic waste: Contains Genotoxic substances which may have carcinogenic
properties. Eg. Cytotoxic drugs, vomit or urine of patients using these drugs.
6. Chemical waste: Lab reagents, solvents, disinfectants
7. Wastes with high content of heavy metal: Mercury
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8. Pressurized containers: Gas, cylinders, aerosol cans
9. Radioactive waste: Unused liquid from radiotherapy, contaminated glassware.
Handling, storage and transportation of health care wastes:
The key to minimization and effective management of health care waste is
segregation and identification of the waste. The most appropriate way of
identifying the categories of health care waste is by. Sorting the waste into color
coded plastic bags or containers. The other practices recommended are,
1. Sharps should be collected together, regardless of whether they are
contaminated or not. Containers should be puncture-proof, rigid,
impermeable, tamper-proof and with covers. Where plastic or metal
containers are unavailable, dense cardboard containers with a plastic lining
are recommended (WHO 1997)
2. Bags and containers for infectious waste should be marked with the
international infectious substance symbol.
3. Highly infectious waste should preferably be packaged in red bags and
sterilized immediately by autoclaving.
4. Expired pharmaceuticals should be returned to the pharmacy for disposal.
5. The identity of the waste should be clearly marked on the container:
Eg. 'Cytotoxic waste' or the name of the chemical in case of chemical waste.
6. Waste with a high content of heavy metals like cadmium or mercury should
be collected separately.
7. Aerosol containers if empty may be collected with general health care
wastes. They should not be incinerated.
Non-hazardous waste should be handled in the same manner as domestic refuse
and collected in black bags.
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Collection:
The waste bags should be tightly closed or sealed when they are about threequarters full. Light gauge bags can be closed by tying the neck but heavier gauge
bags probably require a plastic sealing tag.
• Waste should not be allowed to accumulate at the point of production.
• Waste should be collected daily and transported to the storage site.
• No bags should be removed unless they are labeled.
• The bags and containers should be replaced immediately with new ones of
the same type.
Storage:
The waste should be stored in a separate area, room or building of a size
appropriate to the quantity of waste produced and the frequency of collection.
• The storage area should have an impermeable hard standing floor with good
drainage. It should be easy to clean and disinfect.
• There should be a water supply for cleaning purposes.
• The storage area should allow easy access for staff.
• Easy access for waste collection vehicles is essential.
• There should be protection from the sun.
• It should be inaccessible for animals, insects and birds.
• It should have good lighting and ventilation.
• It should not be located close to food sources.
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Transportation:
Wastes should be transported by means of wheeled trolleys, containers or carts that
are not used for any other purposes. They should,
• be easy to load and unload
• have no sharp edges that could damage waste bags
• be easy to clean
The vehicles should be cleaned and disinfected daily.
Treatment and disposal technologies for health-care waste:
The choice of treatment system for healthcare waste should be made carefully, on
the basis of various factors, many of which depend on local conditions,
• Quantity of waste and disposal capacity of the system
• Type of waste
• Infrastructure requirements
• Training requirements for operation of the method
• Operation and maintenance considerations
• Available space
• Investment and operating costs
• Regulatory requirements
The treatment and disposal options are:
1. Incineration
2. Chemical disinfection
3. Wet thermal treatment
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4. Microwave irradiation
5. Encapsulation
6. Safe burying
7. Inertization
INCINERATION
Incineration is a high temperature dry oxidation process that reduces organic and
combustible waste to inorganic, incombustible matter and results in a very
significant reduction of waste volume and weight.
This process is usually used to treat wastes that cannot be recycled, reused or
disposed off in a landfill site.
Types of incinerators:
1. Double-chamber pyrolytic incinerators
2. Single - chamber furnaces with static grate
3. Rotary kilns
1) Pyrolytic incinerators:
This is the most reliable and commonly used process for health-care waste. They
are also called controlled air incineration or double - chamber incineration. The
pyrolytic incinerators comprises of
• a pyrolytic chamber
• a post-combustion chamber
In the pyrolytic chamber, the waste is thermally decomposed through an oxygen
deficient medium temperature combustion process [800 - 900°C) producing solid
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ashes and gases. The pyrolytic chamber includes a fuel burner, used to start the
process. The waste is loaded in suitable waste bags or containers. The gases
produced in this way are burned at high temperature [90- 1200°C] by a fuel burner
in the post-combustion chamber, using an excess of air to minimize smoke and
odors
The pyrolytic and post-combustion chambers should be of steel with an internal
lining of refractory bricks, resistant to corrosive waste or gas and to thermal shock.
Pyrolytic incinerators are suitable for:
• Infectious waste [including sharps] and pathological waste
• Pharmaceutical and residues.
• They are inadequate for
• Non-risk health care waste
• Genotoxic waste
• Radioactive waste chemical
Drawbacks:
• Relatively expensive equipment
• Expensive to operate and maintain
• Well-trained personnel are required.
Activities involved in operation of pyrolytic incinerators.
1. Removal of ashes left inside the pyrolytic chamber [after cooling down]
2. Loading of waste packages to be incinerated
3. Ignition of the pyrolytic fuel burner to start waste burning in the pyrolytic
chamber
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4. Ignition of fuel burner in post-combustion chamber
5. Monitoring high-temperature burning of gas inside post-combustion
chamber.
6. Stopping the fuel burners after completion of waste and gas burning and
letting the incinerator cool down
Incinerators must be located at a minimum distance of 500 meters from any human
settlement.
2) Single - chamber incinerator:
This can be used for health-care waste if a pyrolytic incinerator cannot be
afforded.This type of incinerator treats waste in batches. Loading and de-ashing
operations are performed manually. The combustion is initiated by addition of fuel
and should then continue unaided.
A 'drum' or 'field' incinerator is the simplest form of a single-chamber incinerator:
It should be used only as a last resort as it is difficult to burn the waste completely
without generating potentially harmful smoke.
A 210 litre steel drum is used, with both ends removed. This will allow the burning
of one bag of waste at a time. A fine screen is placed on the top of the drum to
prevent some of the ash or light material from blowing out. Another screen or fine
grate is placed under the drum and a chimney is fitted on top. This type of
incinerators can also be fabricated from sheet metal or clay.A good fire should first
be established on the ground underneath the drum. One bag of waste should then
be lowered into the drum. Wood should be added to the fire until the waste is
completely burnt. After burning is complete, the ashes from both the fire and the
waste itself should be collected and buried safely. A "brick incinerator" is used in
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similar circumstances and is built by constructing a closed area with brick or
concrete walls.
Drawbacks:
• Chemical and pharmaceutical residues will persist if temperatures do not
exceed 200°C.
• The process will cause emission of black smoke, fly ash and potentially
toxic gases
• Exhaust gas cleaning is not practical - can cause air pollution
3) Rotary kiln:
A rotary kiln comprises of a rotating oven and a post-combustion chamber. The
axis of a rotary kiln is inclined at a slight angle to the vertical [3 - 5° slope]. The
kiln rotates2 -5 times per minute and is charged with waste at the top. Ashes are
evacuated at the bottom end of the kiln. The gases produced in the kiln are heated
to high temperatures to burn off gaseous organic compounds in the postcombustion chamber and typically have a residence time of 2 seconds. Rotary kilns
may operate continuously and are adaptable to a wide range of loading devices.
Those designed to treat toxic wastes should preferably be operated by specialist
waste disposal agencies and should be located in industrial areas.
Rotary kilns can be used for:
• Infectious waste [including sharps] and pathological waste
• All chemical and pharmaceutical wastes including cytotoxic waste.
Rotary kilns are inadequate for:
• Non-risk health-care waste:
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• Incineration in rotary kilns would represent a waste of resources.
• Radio-active waste: Treatment does not affect radio-active properties and
may disperse radiation.
Temperature of rotary kilns: 1200 - 1600°C. This allows decomposition of very
persistent chemicals such as polychlorobi phenyls [PCBs]
Capacity of rotary kilns: Available capacities range from 0.5 - 3 tonnes/hour.
Disadvantages of rotary kilns:
• Well trained personnel are required
• Equipment and operation costs are high
• Energy consumption is high
• Highly corrosive waste and byproducts damage the refractory lining of the
kiln
CHEMICAL DISINFECTION:
In this method, chemicals are added to waste to kill or inactivate the
pathogens.This method is most suitable for treating liquid waste such as blood,
urine, stools or hospital sewage.
Solid wastes and highly hazardous health-care wastes may also be disinfected
chemically, with the following limitations:
1. Shredding or milling of waste is usually necessary before disinfection
2. Powerful disinfectants are required which are themselves hazardous and
should be used only by well-trained personnel.
3. Only the surface of intact solid waste will be disinfected.
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The effectiveness of disinfection is estimated from the survival rates of indicator
organisms in standard microbiological tests.
Types of chemical disinfectants:
1. Formaldehyde
It has an inactivating effect against all microorganisms including bacteria, viruses
and bacterial spores [contact time: 45 minutes]
Gloves and protective eye glasses should be worn during handling of formaldehyde
to protect skin and eyes. In case of skin contact, the area should be rinsed
abundantly with water. Formaldehyde has been classified as a probable human
carcinogen by the International Agency for Research on Cancer.
Therefore, formaldehyde is suitable for use as a chemical disinfectant only in
situations in which a high level of chemical safety can be maintained.
2. Ethelene oxide
It inactivates all microorganisms including bacteria, viruses and spores. It can also
disinfect solid wastes at temperatures of 37.55°C at 60 -809 humidity for 4-12
hours.
Liquid ethylene oxide and aqueous solutions are extremely irritant to skin and
eyes.
Ethylene oxide has been classified as a human carcinogen by the International
Agener for Research on Cancer: Protective measures are therefore necessary. The
use of ethylene oxide is not recommended because of significant health hazards.
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3. Glutaraldehyde
It is active against both bacteria and parasite eggs. It should be used as 2% aqueous
solution with acetate buffer:
Contact time: 5 minutes for disinfection of medical equipment 10 hours to kill
spores. Since concentrated solutions are irritant to eyes and skin, gloves and
protective eye glasses should be worn during handling.
Glutaraldehyde is suitable only in situations in which a high level of chemical
safety can be maintained. Glutaraldehyde waste should never be discharged in
sewers. It may be neutralized through careful addition of ammonia or sodium
bisulfite. It may also be incinerated, after. mixing with a flammable solvent.
4. Sodium hypochlorite:
It is active against most bacteria, viruses and spores but not effective for
disinfection of liquids with high organic content such as blood or stools. Solutions
should be protected from light, which accelerate its decomposition to sodium
chlorate, sodium chloride and oxygen. It reacts with acids to produce hazardous
chlorine gas.
Gloves and protective eye glasses should be worn. Although it is an irritant to skin,
eyes and respiratory tract, sodium hypochlorite may be widely used because of
relatively mild health hazards.
5. Chlorine dioxide
It is a reddish - yellow gas at ambient temperature. It will react with water or steam
to produce corrosive fumes of hydrochloric acid. It is active against most bacteria,
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viruses and spores. It is an irritant to skin, eyes and respiratory tract. It is widely
used in drinking water preparation, sanitation and waste water treatment.
WET THERMAL TREATMENT:
Wet thermal treatment or steam disinfection is based on exposure of shredded
infectious waste to high-temperature, high-pressure steam. It inactivates most types
of microorganisms.
This process requires that waste be shredded before treatment to increase
disinfection efficiency. The process is inappropriate for the treatment of anatomical
waste and animal carcasses.
The disadvantages are:
• The shredder is liable to mechanical failure and breakdown
• The efficiency of disinfection is very sensitive to operational conditions
• The advantages are:
• Relatively low investment and operating costs
• The low environmental impact
Autoclaving is an efficient wet thermal disinfection process. They allow for the
treatment of only limited quantities of waste and are therefore commonly used only
for highly infectious waste, such as microbial cultures or sharps.
MICROWAVE IRRADIATION:
Most microorganisms are destroyed by the action of microwaves of a frequency of
about 2450 MHz and a wavelength of 12.24 cm. The water contained within the
wastes is rapidly heated by the microwaves and the infectious components are
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destroyed by heat conduction. Although this process is becoming increasingly
popular, relatively high costs coupled with potential operation and maintenance
problems mean that it is not yet recommended for use in developing countries.
ENCAPSULATION
This procedure involves filling containers made of high density polyethylene or
metal drums, with waste. These containers are them filled up with a medium of
immobilizing material such as plastic foam, cement mortar or clay. After the
medium has dried, the containers are sealed and disposed off in landfill sites. It is a
simple, low-cost and safe method but not recommended for non-sharp infectious
waste.
SAFE BURYING:
Safe burial of waste may be used when this is the only viable option available
especially in establishments which use minimal programs for health care waste
management. However, certain basic rules should be followed,
• Access to the disposal site should be restricted to authorized personnel
only.
• The burial site should be lined with a material of low permeability like
clay.
• Only hazardous health-care waste should be buried, so as to conserve
space.
• Large quantities of chemical waste should not be buried at one time to
avoid environmental pollution
• The burial site should be covered with a layer of earth to prevent health
hazard
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INERTIZATION:
This process involves mixing waste with cement and other substances before
disposal in order to minimize the risk of toxic substances contained in the waste
migrating into surface water or ground water. It is especially suitable for
pharmaceuticals and for incineration ashes with a high metal content. This is a
relatively inexpensive method of waste disposal but it is not applicable to
infectious waste.
CONCLUSION
The key to man's health lies in his environment. Much of man's ill-health can be
traced to adverse environmental factors such as water pollution, air pollution, poor
housing conditions and presence of vectors of diseases which pose a constant
threat to man's health. The purpose of environ mental health is to create and
maintain ecological conditions that will promote health and thus prevent disease.
International Biohazard symbol
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