Biofilm growth-percolation models and channeling in biofilter clogging.

Biomass accumulation is a load-limiting factor in the operation of biofilters used for air pollution control. As the biofilm thickens, portions at the base are no longer exposed to contaminants and oxygen and, thus, provide no treatment. Smaller pores are filled with biomass so that air no longer flows into them.

Removal of ultrafine and fine particulate matter from air by a granular bed filter.

The removal efficiency of granular filters packed with lava rock and sand was studied for collection of airborne particles 0.05-2.5 microm in diameter.