PERFORMANCE STUDIES ON BIOFILTRATION OF BENZENE AND XYLENE VAPOURS IN A PURE AND MIXED FORMS - KINETICSAND MODELLING

摘要

Benzene and xylene are produced in large quantities in the petrochemical industries and have been listed among the hazardous and toxic atmospheric contaminants due to their adverse effects on environment and human health. In this study experiments were conducted to evaluate the performance of biofilters in treating benzene and xylene. The bench scale biofilters was operated in long term experiments in order to study the removal of benzene and xylene as a mixture. The biofilter media consists of a mixture of casuarina seeds and berl saddles (50: 50 vol-%). The media was mixed with wastewater sludge obtained from the paper industry as inoculum. The biofilters were operated at different inlet concentrations of VOCs (0.2 to 1.2 g~(-3)h~(-1)) and at a gas flow rate of 0.03 m3/h. Maximum Removal efficiencies higher than 95% were obtained with the mixture of benzene 60 % and xylene 40 % of inlet concentration. Further increase in the xylene concentration caused a drop in the removal efficiency. Ottengraf-van den Oever model was tested and fitting demonstrated a good agreement between calculated and experimental data for pure VOCS and mixed VOCs.