Effects of nitrogen source, empty bed residence time and inlet concentration on biofilter removal of chlorobenzene

A new biofilter with bamboo carriers was used to remove gaseous chlorobenzene. Operating parameters such as the nitrogen source, the empty bed residence time (EBRT) and the inlet concentration of chlorobenzene were varied. The ability of the biofilter to remove chlorobenzene was evaluated under each set of conditions. The experimental results indicated that better biofilter performance was achieved using ammonium instead instead of nitrate nitrogen as the nitrogen source. However, an addition of excess ammonium did not further increase the removal efficiency. The optimal ration of carbon to nitrogen supply (C/N) was 7:1-14:1. Increasing EBRT increased the biofilter efficiency from 0-20% (EBRT = 24s) to 30-50% (EBRT = 41s) and to 50-70% (EBRT = 122s). The relationship between removal efficiency and EBRT indicated that the removal of chlorobenzene is a pseudo first order kinetic process below the concentration of 400 mg/m(3). A substrate inhibition model the Haldane equation, successfully described the removal rate of the biofilter at various inlet concentrations. With increasing inlet concentration, the biofilter at various inlet concentrations. With increasing inlet concentration, the removal rate initially rose and then declined. The highest removal rate of 18 g/m(3) x h was achieved at an inlet concentration of 1440 mg/m(3).