Removal of VOCs from contaminated gas streams by biofiltration

Widespread emissions of hazardous pollutants such as benzene, toluene, and xylenes (commonly called BTX) in chemical and petrochemical industries have caused considerable concern over their potential adverse effects on human health and the environment. BTX compounds are among the hazardous air pollutants (HAPs) identified by the U.S. Environmental Protection Agency (USEPA). The presence of these compounds at even low concentrations in the ambient air has adverse impacts on human health. These substances are toxic to the liver, kidneys, and central nervous system as they enter the body by skin contact or by breathing (Akers et al., 1999; Fishbein, 1985; Olaniran et al., 2001). These compounds have been the subject of extreme importance in recent environmental regulations. Although industries emitting volatile organic compounds (VOCs) are required to install control devices to reduce their emissions, it is not widely practiced due to lack of cost-effective techniques, resulting in increasing concentrations of VOCs in ambient air. This need for cost-effective techniques prompted this study on biofiltration of BTX compounds; the results are presented in this chapter.