Air coming out of wastewater treatment plants (WWTP) always contains H₂S (Hydrogen Sulphide) and Total Reduced Sulphur compounds (TRS) such as DMS (Dimethyl Sulphide) or MM(Methyl Mercaptins). Reducing H₂S does not assure the removal of bad odors from the air since TRS contributes significantly to odor problems even in very low concentrations.  Simply cutting H₂S amounts in half is not likely to be a noticeable reduction in smell. 


A very effective way of treating this smelly air is by using biotrickling filters (used for high concentrations of H₂S) followed by biofilters (where total odor removal is required).  Both a biotrickling filter and biofilter are made up of a media upon which grows naturally occurring bacteria.  By passing this air through the media the bacteria digests the contaminants in the air that contributes to odor thus purifying the air.  Biotricklers are able to handle very high concentrations of H₂S while biofilters handle lower concentrations but are also able to handle the TRS.  The two biggest advantages of using these technologies are that there are no environmental side effects and that total odor removal is achievable.

Biofilters are also able to handle other compounds such as Volatile Organic Compounds (VOC’s).  This widens the use of these technologies into many other areas such as composting plants, industrial plants and energy from waste plants where odor and other pollutants need to be removed from air.

Technology Comparison