Biological Treatment of VOCs

    Volatile organic compounds (VOCs), together with particulate matter, sulfur oxides and nitrogen oxides, are major components of air pollution that can lead to serious environmental and health hazards. Physical, chemical and biological treatment methods are available to remove VOCs from the air by either recovery or destruction [1-3]. Biological treatment methods, while less well-established than some of the other methods, can offer advantages over physical and chemical approaches. Table 1 compares the various methods with respect to the maturity of the technology, capital and operating costs, operability range, safety issues, nature of side products and potential downstream issues. In some cases, a hybrid approach that combines more than one technology can be advantageous over the individual treatment procedures. VOCs generally have low boiling points and hence vaporize readily. These emissions originate from many places, including the chemical process industries (CPI), where sources include breathing and loading losses from storage tanks, venting of process vessels, leaks from piping and equipment, paint booths, wastewater streams and losses from heat exchangers. The compounds from which the VOCs arise may include, for…