ABSTRACT
The biological treatment of volatile organic compounds and other pollutants has received increasing attention. Biofiltration involves the removal and oxidation of organic compounds from contaminated air by beds of compost, peat, or soil. The simplest biofiltration system is a soil bed, where a horizontal network of perforated pipe is placed about 2 to 3 ft below the ground. Biofiltration combines the mechanism of adsorption, the washing effect of water, and oxidation. A biofiltration system uses microorganisms immobilized in the form of biofilm layer on an adsorptive filter substrate such as compost, peat, or soil. As a contaminated vapor stream passes through the filtered bed, pollutants transfer from the vapor to the liquid biolayer and oxidize. Biofiltration has been used for many years for odor control at slaughter houses in Germany, the Netherlands, the United Kingdom, and Japan and to a limited extent in the United States. Many wastewater and sludge treatment facilities have used biofilters for odor control purposes.
