[Performance of trace ozone-augmented biological trickling filter in toluene degradation]

Biological Trickling Filter (BTF) is the most widely applied bioreactor for waste gas purification. However, the biological clogging and performance deterioration during the long-term operation are considered to be common hurdles in its application. In this study, ozonation as a new control strategy was proposed for regulating biofilm thereby strengthening the long-term operation of BTF, which demonstrated significance from both engineering and science standpoints. BTF introduced with intermittent trace ozone (40 mg x m(-3)) could achieve a longer duration of stable performance comparing with the conventional BTF. In this study, the O3-BTF was continuously operated for over 180 days. The removal efficiency, mineralization extent and the maximum elimination capacity (r(max)) of 03-BTF was over 80%, 87.1% and 95 g (m3 x h)(-1), respectively. The maximum AWCD values of the upper and lower sections in the O3-BTF were higher than those of the control BTF, illustrating the trace ozone could improve the metabolic activity of the biofilm. In the later period, the porosities of the control BTF and O3-BTF were 55% and 60% , respectively, pressure drops of the control BTF and O3-BTF were 103.2 Pa and 44. 1 Pa, respectively, and the average biomass contents were 36.59 mg x g(-1) and 29.12 mg x g(-1) in the respective reactors. Based on the above results, the trace ozone could effectively prevent the clogging of the medium and performance deterioration, thus keep BTF continuously operating for a longer period. Besides, ozonation could enhance the long-term operation efficiency, toluene elimination capacity and mineralization rate of the BTF.