Biofiltration compared to chemical scrubbing for odor control Definition of concepts and background information Due to high levels of industrialization, food processing has increased and this means that the environment is being affected by the odors emitted from the plants of processing (Hedley 2002, p.99). Processing plants are near residential areas so that they can get workforce from the neighborhood and this means that the odor coming from the industries must be dealt with to avoid adverse effects to the people, plants and animals.