微量臭氧强化生物滴滤降解甲苯性能研究

生物滴滤(BTF)是目前废气生物处理研究和应用最多的工艺,其长期运行填料层堵塞和运行性能恶化是该技术工程应用面临的共性科学技术难题.本研究提出利用微量臭氧化调控生物膜相,进而强化反应体系长期稳定运行.结果表明,生物滴滤塔间歇通入40 mg·m-3的微量臭氧,可延长反应体系的运行周期(本实验运行180 d),并保证甲苯去除率维持在80%以上,最大去除负荷达到95 g·(m3·h)-1,矿化率达到87.1%.O3-BTF的上、下段最大AWCD值分别为0.90、1.08,明显高于BTF体系,表明微量臭氧在运行后期可明显改善生物膜的代谢活性.床层特性与平均生物量表明,BTF和O3-BTF运行后期,平均生物量分别为36.59 mg·g-1和29.12 mg·g-1,床层孔隙率分别为55%和60%,压降分别为103.2 Pa和44.1 Pa.上述实验结果表明,生物滴滤降解甲苯长期运行过程中,微量臭氧能有效控制填料层堵塞和运行性能恶化,维持生物滴滤塔长期高效运行,并且对甲苯的去除和矿化具有一定的强化作用.

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·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 (rmax) of O₃-BTF was over 80%, 87.1% and 95 g·(m³·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·g^-1 and 29.12 mg·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.