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Incineration: How Medical Waste is Incinerated

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Incineration is a thermal process that reduces organic and combustible waste into inorganic, incombustible matter. This high temperature reduces the waste volume and weight and works best for waste that cannot be disposed of, reused, and recycled.

Unlike waste disposal methods like autoclaving, incineration requires no pre-treatment to destroy medical waste. It works effectively for different types of medical wastes such as:

•    Human waste such as body parts, body fluids, blood, and, tissues.
•    Dressing materials.

However, incineration cannot be used for wastes such as pressurized gas containers, waste with high mercury, radiographic waste, or a large amount of reactive chemical waste. For chemical and pharmaceutical wastes to be destroyed, very high temperatures will be needed. Normally, medical waste incinerators operate at high temperatures of between 900 to 1200 degrees Celsius.

Today, medical waste incinerators are becoming popular in developing countries where mobile incinerators are used on-site in hospitals and clinics. Developing countries in Africa and Asia use incinerators that are cost-effective and feature simple designs.

In India, hospitals use small-scale decentralized incinerators with a capacity of 200-1000kg per day while off-site regional facilities use large-scale incinerators that have a capacity of 1-8 tonnes per day.
Pyrolytic incineration is the most reliable and popular medical waste incineration technology. This incinerator is also known as a double-chamber incinerator or controlled air incinerator and is designed with a post-combustion chamber and pyrolytic chamber.

The process involves thermally decomposing medical waste into the pyrolytic chamber via an oxygen-deficient combustion process with a medium temperature of 800-900 degrees Celsius. Consequently, this produces gases and solid ashes.

The gases produced are then burned in the post-combustion chamber by a fuel burner at a high temperature of 900 to 1200 degrees Celsius. During the process, excess air is used to lower the production of smoke and odor.
Although incinerators are becoming popular in developing countries, the WHO has said that there could be risks associated with them. These risks are in the form of carbon monoxide, acid gases, pathogens, organic compounds, particulate matter, heavy compounds, and dioxins.

Following this, most industrialized countries like the USA, Portugal, Germany, Canada, and Ireland are phasing out medical waste incinerators. Instead, they are investing in technologies that don’t produce dioxins.