The Application of Air Modeling to Show the Reduction of Off-gas Odour from an Industrial Fermentation Process Using Biofiltration

Biofiltration is an inexpensive method of odour removal in which a contaminated air stream is passed through a moist, porous medium before being vented to the atmosphere. Contaminants are absorbed onto the surface of the medium and degraded by microorganisms. Using an air model, the odour reduction resulting from the use of a vertical, lab-scale biofilter in treating off-gases intermittently released from a local fermentation facility was described. The filter was operated for two months, totaling 30 medium sterilizations, and the relationship between odour reduction and off-gas flow rate was examined. The filter maintained an odour reduction above 35%, and sustained odour reduction over consecutive sterilization cycles. An AUSPLUME dispersion model was used by inputting all necessary parameters inherent to the study site and weather conditions to compare the theoretical dispersion of stack emissions before and after implementation of a the biofilter. The analysis showed that the biofilter reduced the odour to below the minimum annoyance level of 5 OUm, thereby lowering the likelihood of complaints from neighbouring facilities.