Air Pollution Technology and Medical Waste

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Pollutants

• Sulfur dioxide - produced in combustion
• Carbon monoxide - produced in inefficient combustion
• Aldehydes - produced in decomposition of animal bodies (fats, oils)
• Nitrogen oxides - produced in combustion
• Phosgene - produced in decomposition of chlorinated hydrocarbons
• Suspended particulates - many types of operations produce solid and/or liquid particles that become suspended in air and are referred to as “particulates”. They range up to 1 millimeter in diameter.
• Odor - produced by many sources

Methods of Dealing with Air Pollutants

Electrostatic precipitators

Upsides

• Can be extremely efficient, especially is processing a steady waste stream
• Can remove very small particulates
• Low pressure drop through unit
• Can operate at high pressure and/or high temperature

Downsides

• High cost - capital cost
• Ozone produced in operation
• Removes particulate but not dissolved gases
• High voltages can be hazards for personnel
• Big floorplan
• Cannot handle input streams that vary in composition and flowrate without loss of efficiency
• Unsuitable for some waste streams (e.g. contain combustibles)

Condensers

Upsides

• Can recover condensed material that might be useful
• No need to add material to waste stream

Downsides

• Hard to get pollutants down to very low levels just by condensing
• Coolant system cost (capital and operating) and complexity

Combustion

Upsides

• Simple, can destroy a lot of chemical compounds
• Really efficient destruction of organic contaminants if operated correctly
• Generation of heat which can be useful.

Downsides

• High operating costs - fuel, personnel
• Hazards of playing with fire
• Potential for incomplete combustion and production of carbon monoxide and other hazardous chemicals such as dioxins

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