Gasoline Vapor Biofiltration

While gasoline vapor emissions are common sources of air pollution, very few results have been published on the biofilter biodegradation of gasoline vapors in flowing waste gases. This investigation reports on a bench‐scale biofilter of an ID of 50 mm and a bed height of 850 mm with an inexpensive fire clay chip medium as a packing material. The biofilter was inoculated with a concentrate of a mixed culture of the common microflora. After an acclimatization period of three weeks, loading tests were carried out at increasing gasoline inlet concentrations at a constant Empty Bed Retention Time (EBRT) of 16 min. Evaluating the removal rate and efficiency of aliphatic and aromatic fractions of the gasoline vapor, it was found that in a range of overall organic loading (OL_TPH) up to 33.6 g/m³ h the removal efficiency of aromatic hydrocarbons decreased from 90 to 70 %, while that of the aliphatic components decreased much more significantly from 60 to 10 % after six months of operation. The removal rate and efficiency achieved for total petroleum hydrocarbons were 13 g/m³ h and 45 %, respectively. The microbial strains and genera of culturable cells in the inoculum and in the biofilm after six months of gasoline degradation were evaluated.