One particular objective of this study is that of promoting compost as a viable biofilter-filling material.
Previous studies Wu et al., 1999 have demonstrated that the use of peat ‘beads’, bound together with a
binder, has several advantages over other types of biofilter media. Consequently another objective of the
study is to demonstrate that a bed composed of a compacted mixture of compost and a particular binder
substance has advantages, e.g. resistance to clogging, easy washing, and satisfactory performance in comparison
to some alternative materials. Thus, a further objective of this paper is to demonstrate that our
‘innovative’ bed material performs well in the task of the biological removal of toluene a (widely used VOC
in industry) from air Environnement Canada, 1992 . A natural ‘feature’ of the biofiltration work with this
compost is that no micro-organisms are introduced into the filter-beds in order to take full advantage of the
particularly rich microflora already present in the selected compost. From the experimental results obtained,
a simple model, based on Ottengraf and van der Oever, 1983 , was subsequently established to present .
the results in a systematic and more meaningful form.Plexiglas tube having a 15.3-cm internal diameter. It
was divided into three 45-cm high sections, each section being filled to a height of 33-cm with equal amounts
of the prepared filter-bed material. In order to support the filter-bed and to ensure homogeneous radial distribution
of the input gas, a stainless steel mesh was installed at the base of each section. These supports were reinforced with stainless steel rods in order to bear the weight of the wet filter material. The biofilter was fed by a measured primary airflow, provided by a continuous compressed air source, the delivered air flowing through a water column in order to become fully saturated. A secondary fraction of the main airflow was directed to a ‘bubbler’ unit containing the
liquid toluene reagent (Fischer Scientific, 99.9% pure). The now ‘pollutant’-saturated gas was carried through
Teflon-internally-coated tubing in order to prevent toluene reaction with the tube material. The previous
separate gas flows were then mixed together and the resultant polluted humid input gas mixture was carried
to the base of the biofilter.