Microbial biofilter for toluene removal: Performance evaluation, transient operation and theoretical prediction of elimination capacity

Toluene contributes a major part amongst the hazardous volatile organic compounds (VOCs). In this present work, toluene removal in a novel lab scale biofilter packed with ceramic beads and compost has been studied after 20 d of acclimatization. For different initial toluene concentrations (0.2-3.7 g m−3), the elimination capacity (EC) and removal efficiency (RE) are studied. A maximum EC of 96 g m−3 h−1 was found at the toluene inlet loading rate of 98.8 g m−3 h−1 with high RE of 97% during its 22 d continuous operation. The removal of toluene biofilter was better at the entry section of the contaminated air. The study also showed stability of biofilter during transient operation in treating toluene. The experimental EC values are compared with theoretical EC values from mathematical model. The theoretical average biofilm thickness was found to be 0.47 mm. The Ottengraf mathematical model was able to predict the theoretical EC at different regime of biofilter operations.