Biofiltration of volatile organic compounds and polycyclic aromatic hydrocarbons

Indoor and outdoor air pollution is a complex and multifactorial problem involving particulate matter (PM), biological agents, and gaseous pollutants. Several organizations, such as the World Health Organization, the United States Environmental Protection Agency, or the French Indoor Air Quality Observatory, have established acceptable levels for indoor air pollutants including volatile organic compounds (VOCs, such as benzene and formaldehyde) and polycyclic aromatic hydrocarbons (PAHs), among many other compounds, based on their ubiquity, concentration and sources, being motor vehicle emissions, cooking, smoking, and residential heating the chief sources of VOCs and PAHs.
Despite the abundance of studies demonstrating the potential of biological methods to eliminate VOCs in laboratory scale, less is known regarding the elimination of PAH vapors by biological systems at concentrations typically found in polluted environments.
This chapter introduces the problem of VOCs and PAHs as air contaminants and the fundamentals of biofiltration as a technology for their elimination. Research in this area has been active during the last decades, and a thorough revision of the discoveries is provided before introducing the most important considerations in the design and operation of biofilters for the treatment of VOCs and PAHs, including pH, temperature, selection of the packing media, and the microorganisms used for inoculation. The later might influence the mass transfer, solubility, and biodegradation of this type of contaminants as the use of filamentous fungi (along with bacteria forming a consortium) can promote the direct absorption of VOCs and PAHs, from the gas phase.