High-performance biofilters for air treatment applications

Biofilters are air-phase biological reactors used for treatment of industrial air pollutants, which include odorous compounds such as hydrogen sulfide and ammonia or volatile organic compounds (VOCs) such as benzene and toluene. United States Environmental Protection Agency classified more than 180 compounds as hazardous air pollutants (HAPs) which can cause serious health and environmental problems. Many of the listed HAPs are VOCs that can be treated by biofiltration. In the last two decades, biofilter technology, which is based on biooxidation process, has gained importance for industrial air treatment over conventional technologies due to many advantages. Interactions between biooxidation process and mass transfer effects of pollutants in the gas as well as biofilm phases make this process complex. Continuous research and development is underway to make this technology highly efficient and feasible for different environmental and operational conditions. In this chapter, an overview of biofiltration process, key factors that contribute to efficient biofilter performance, and recent applications, which use conventional as well as innovative packing materials, are discussed. Furthermore, advances in biofiltration, biofilter configurations, and future direction in biofilter applications are presented.