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Autoclaving is a time-tested process of
sterilization of medical waste using high temperature and high-pressure
steam. Effective sterilization results in the destruction of bacteria,
viruses, spores, fungi and other pathogenic micro-organisms. Conventional
autoclaves are essentially cylindrical vessels with a provision for loading
and unloading waste. Steam at high temperature and pressure is introduced
into the vessel jacket. The steam transmits heat rapidly to the waste which
in turn produces steam of its own. |
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Salient Features
1. The process effectively destroys pathogens and
renders the waste dry.
2. Typical operating conditions for an autoclave
are a temperature of at least 121°C at a pressure of
105 kPa for a period of
at least 60 minutes.
3. The widely used autoclaving methods include: the
induced vacuum method, where the steam is
introduced into a vacuum, and the
gravity displacement method, where in the steam entering the
chamber
displaces the air.
4. The penetration of steam into the waste is crucial to
the effectiveness of the treatment and therefore
attention must be paid to
packing the waste in a manner promoting penetration.
5. Any liquid waste
formed may need to be treated before disposal.
Advantages
1. The autoclave process is an appropriate
technology for the treatment of microbiology laboratory
waste, human blood
and body fluid waste, waste sharps and non-anatomical waste.
2. The treated
residue is acceptable for disposal in a municipal landfill, if shredded or
macerated to
render it unrecognizable and in the case of sharps, incapable
of causing injury.
3. The Bio-Medical Waste (Management and Handling) Rules,
2000 recommend autoclaving for
disposables, microbiological waste and
sharps.
4. Simple maintenance procedures and a low cost of maintenance make it
a popular technology for
waste treatment.
5. It is commercially available in
various sizes in the Indian market.
6. Servicing facilities are also available
in most cities.
7. Waste is reduced by an estimated 30% of its volume,
enhanced, if accompanied by mechanical
shredding and can either be landfilled directly or compacted further.
8. Anatomical and pathological
wastes, low-level radioactive waste, organic solvents, laboratory
chemicals
and chemotherapy waste should not be treated in an autoclave.
9. Operational
malfunctioning may result in ineffective treatment.
10. Steam treatment wets the
waste resulting in an increase in weight. But compared to incineration,
the
reduction in volume is small.
11. The capital and operating costs for an
autoclave are as compared to that for other treatment
options. |
