Webster Environmental Associates, Inc. products

Biofilters are an odor treatment technology that utilizes biological processes as the treatment mechanism. Biofilters are considered to be a “green” approach to odor control, because they utilize microorganisms in media to oxidize odor and air emission compounds to carbon dioxide, water, biomass, and other benign by-products such as chloride and sulfate. The by-products are either emitted in the outlet air, drained from the biofilter, or consumed by the microorganisms. The biological activity in a biofilter is similar to the activities performed by the microorganisms in activated-sludge secondary wastewater treatment processes.

Biotrickling Scrubbers are an odor treatment technology that utilizes biological processes, as opposed to chemical processes as their treatment mechanisms. They are similar to biofilters in this regard. Biotrickling scrubbers use artificial media and closed vessel construction, where biofilters often use natural media and open bed construction.

Activated carbon has a complex pore structure with a very large surface area.  Odorous compounds are transferred from the air being treated to the surface of the carbon as the air is forced through the carbon bed.  There is a physical attraction between the compound and the carbon once contact is made which causes a bonding.  The compounds will continue to adsorb onto the surface of the carbon until all of the pore space in the carbon is used up.  When that happens odors will breakthrough and the carbon has to be replaced or regenerated.