How do biofilters work in air pollution control?

• A. By using chemicals to neutralize pollutants
• B. By filtering air through physical barriers
• C. By using microorganisms to degrade pollutants
• D. By absorbing pollutants with activated carbon

Answer: (C)

Biofilters work by utilizing microorganisms to degrade pollutants found in the air. In a biofilter system, contaminated air is passed through a filter media that is typically populated with a diverse population of bacteria, fungi, and other microorganisms. These organisms metabolize and break down harmful pollutants into less harmful substances, often converting them into carbon dioxide, water, and biomass.

The process operates on the principle of bioremediation, where biological agents are employed to detoxify and rehabilitate polluted environments. The efficiency of a biofilter in treating air pollution depends on factors such as the residence time of the air within the filter, the type of pollutants present, and the health and activity level of the microbial community.

Unlike methods that rely on chemicals, physical barriers, or activated carbon, which focus on various forms of adsorption or filtration, biofilters specifically leverage biological processes, making them a sustainable option for controlling air pollution. They are particularly effective for volatile organic compounds (VOCs), odors, and certain inorganic gases. This biological approach not only offers effective pollutant removal but can also contribute to a reduction in overall environmental impact.