Biological treatment of benzene vapors in biofilters

Biofiltration has been recognized as a cost effective technology for the purification of air contaminated with low concentrations of biologically degradable contaminants. Biofilters are packed columns with biologically active materials such as immobilized cells and compost or inorganic or polymeric media on which immobilized microbial mass is attached. Biotrickling filters employing synthetic, inorganic media yield more uniform gas distribution and biological contact. Hydrophilic volatile organic compounds (VOCs) are easily degradable while hydrophobic ones pose a great challenge for adequate treatment due to the transfer of the VOC to the liquid phase. This chapter will review the current status of biotechnology treatment. Different techniques of biodegradation of benzene in biotrickling filters will be presented including pH change, biomass accumulation and empty bed resident time. Biodegradation of benzene as sole VOC in addition to benzene in mixtures of benzene, toluene, and xylenes (BTX) and benzene, toluene, ethylbenzene and xylenes (BTEX) and others are also considered.