Procedurally, the biofilter consists of an organic and damped packing. The air to be treated flows through the packing with minor velocity. The packing naturally contains a microflora that increases with convenient milieu conditions and adapts to the components which are to be removed.
When flowing through the organic biofilter bed, the contaminants are being absorbed by the filter material and dissolved in a thin liquid film which is around the filter material. The now dissolved contaminants enter the cells of the microoganisms by means of diffusion and osmosis and are decomposed into harmless products.