Biofiltration is a technology by which the gaseous emissions to be treated are conveyed through a biologically active porous medium.

This is nothing more than a sort of bed made up of materials such as bark, shredded wood, mature compost, and peat kept at constant temperature and humidity conditions and colonized by aerobic microorganisms capable of degrading the compounds to be treated present in the airstream.

It is important to emphasize that colonization and metabolic activities occur within the biofilm which, in this case, is the water film that is created around the particles of the solid part of which the biofilter is made.

Before leaving the filter bed, the airstream is enriched with carbon dioxide, of the others volatile organic compounds produced and the heat generated by biochemical reactions.