DYNAMICS OF TOLUENE DEGRADATION IN BIOFILTERS

Biodegradation processes have been validated as a promising alternativ e to other conventional air pollution control technologies. The object ive of this research was to systematically investigate the transient b ehavior of shut down and restart-up operation and shock loading of the biofilter. Experiments were conducted in three laboratory-scale biofi lters with mixtures of chaff/compost, D.E.(diatomaceous earth)/compost , and GAC(granular activated carbon)/compost, respectively as the filt er materials. Toluene was used as the gas pollutant in this study. The response of each biofilter to shock loading was studied by abruptly c hanging the concentration or flow rate of the inlet gas. For each tran sient operation, toluene concentration was continuously measured until a new steady state was achieved. The results indicated that the biofi lters responded effectively to the shut down and restart-up operation and shock loading of toluene concentration or gas flow rate. Moreover, the highly adsorptive GAC could improve the biofilter performance, es pecially for the treatment of less water soluble compounds such as tol uene. Therefore, the GAC/compost biofilter had the highest maximum eli mination capacity of 97 (g hr(-1) m(-3)).