Several methods of disposal may be used in pharmaceutical waste management.
1. Incineration or thermal treatment: In this method,
solid organic waste materials are incinerated or burnt to convert them into
gaseous products and a solid residue in the form of ash. This is one of the
most effective methods and can be used for the disposal of solid, liquid as
well as gaseous wastes. While there are mixed opinions on its dangers such as the
emission of polluting gases, it is certainly one of the best ways to dispose of
hazardous wastes such as biomedical waste.
This method is unsuitable for wastes that are highly
reactive chemicals containing halogens, halogenated plastics, mercury,
pressurized gases, and radiographic waste.
The ash produced after incineration must be disposed of in a
secure landfill. There must be arrangements to prevent gases produced during
the combustion process from causing air pollution.
2. Chemical disinfection: This method involves
treating waste materials with some chemicals that will inactivate the chemicals
or biological materials that may be present in liquid waste. The effectiveness
of the process depends on the type of chemical used, its concentration, and the
nature of contact between the disinfectant material and the waste.
3. Microwaving: Microwaving involves the use of
microwave radiation and can destroy the infectious materials in biomedical
waste. It is advantageous because the electricity requirement is less; steam is
not needed either. However, it is not very suitable for pharmaceutical waste.
Also, waste must be shredded before microwaving to allow the
radiation to come into contact with the waste material.
4. Autoclaving: Here, saturated steam is passed
through the waste in the autoclave for a duration and at a temperature
sufficient to destroy pathogens. This is most commonly used for biomedical
waste disposal and also for waste generated from the microbiological testing
laboratory. The waste produced after autoclaving must be disposed of by
landfilling. Autoclaving is not the best method for chemical or pharmaceutical
waste.
5. Secure landfilling: Here, the wastes are disposed
of by burying them in a landfill that has been designed to contain the
hazardous wastes. Unless properly designed and operated, the landfill may lead
to liquid leaching into the groundwater, attraction of vermin, and other such
problems. It is also important to have gas extraction systems in landfills to
remove the carbon dioxide and methane that are produced by the anaerobic
breakdown of waste.
6. Deep burial: In this method, waste is buried in
deep pits or trenches that are at least 2 meters deep. One must ensure the soil
is impermeable in these areas, and that there are no shallow wells in the area
to avoid the risk of water contamination. Half the pit is covered with biomedical
waste, and the rest is filled with lime, stopping 50 cm below the ground
surface. The final layer of the pit is made up of soil to cover the waste. Such
burial should be done only in areas that are not prone to flooding.
7. Waste encapsulation – immobilization:
Encapsulation of waste involves making waste immobile in the form of a solid
block contained within a steel or plastic drum. Clean drums are filled to 75%
of their capacity with waste; the remaining space is filled with either cement
or lime-cement mix, or bituminous sand or plastic foam. The drum is then sealed
and placed at the bottom of a landfill and fresh solid waste is covered on top
of it.
8. Waste immobilization – inertization: Inertization
involves grinding pharmaceutical products after removing them from the packing
materials. The ground product is mixed with cement, water, and lime and made
into a paste. This paste is transported to a landfill and poured into normal
waste where it sets as a solid mass.
9. Sewer treatment: Liquid drug products can be
largely diluted by mixing with water and flushed down the sewer very slowly in
small quantities. Small quantities of very diluted medicines may be flushed
down fast-flowing water bodies too.