Innovative Methods in Biofiltration of Air Contaminants

Abstract

Biofiltration is an effective, economical and environmentally benign technology for treating contaminants from industrial airstreams. It is based on the ability of microorganisms to oxidize (degrade) toxic and odorous air contaminants. The contaminants treated in a biofilter are biodegradable volatile organic compounds (VOCs) or inorganic odifer-ous compounds. These compounds are released from various industrial sources such as wastewater and petrochemical industries, rendering plants, composting facilities, coating industries, and food processing industries. These chemicals are emitted in large amounts and create hazards to the ecosystem and to human health. The VOCs, many of which are carcinogens, are also precursors to smog formation. Inorganic contaminants (hydrogen sulfide, ammonia) and reduced sulfur compounds (methyl mercaptan, dimethyl sulfide and dimethyl disulfide), prevalent in municipal wastewater collection and treatment systems, are highly odorous, and thus create a nuisance in the environment. The regulatory agencies have set strict controls on emission of VOCs and odorous gases. The United States Environmental Protection Agency (USEPA) enforces strict controls on more than 180 hazardous air pollutants (Guilbault 2002). The market for the removal of odor and VOCs is driven by regulatory issues, generally enforced as a result of public complaints about poor local air quality and through emissions monitoring by the enforcement agencies. International protocols, such as those for the reduction of greenhouse gases, are resulting in increased regulations and enforcement of the regulations (Shareefdeen et al. 2003).