BIOFILTRATION OF BENZENE CONTAMINATED AIR STREAMS USING COMPOST-ACTIVATED CARBON FILTER MEDIA

Three laboratory-scale biofilter columns were operated for 81 days to investigate the removal of benzene from a waste gas stream. The column s contain an mixture of yard waste and sludge compost as biomedia. Dif ferent amounts of granular activated carbon (GAC) are mixed with the c ompost in two of the three columns to evaluate the extent to which bio filter performance can be enhanced. The effects of different operating conditions on the performance of the removal of benzene from air were evaluated. More than 90% removal efficiency was observed for an influ ent benzene concentration of about 75 ppm and an air flow rate of 0.3 L/min. in all 3 columns under steady-state conditions. Under most case s of shock leading conditions, such as a sudden increase in the air fl ow rate, or the benzene concentration in the influent, the biofilters containing GAC provided higher removal efficiencies and more stable op eration than the biofilter containing compost only.