Lo Cheng-Shing, Hwang Shyh-Jye
Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
Environ Sci Technol. 2004 Apr 1;38(7):2271-80. doi: 10.1021/es030455z.
Suspension microorganisms in an internal-loop airlift bioreactor were utilized to treat waste gas containing toluene. The working volume of the reactor was 35 L, and the biomass concentration was 3 kg/m3. The gas pollutant flowed into the reactor from the bottom; it then transferred from the gas phase to the liquid phase and was degraded by the microorganisms suspended in the liquid phase. The microorganisms were able to degrade 50-90% of the inlet toluene when its concentration was from 0.5 to 10 g/m3, and the superficial gas velocity ranged from 0.15 to 1.23 cm/s. A comprehensive mathematical model was also developed to describe the overall degradation process of toluene in the internal-loop airlift bioreactor. The overall degradation process included gas flow, gas-liquid mass transfer, flow and dispersion of the liquid phase, and microbial kinetics. The hydrodynamic properties including the gas and liquid superficial velocities, the gas holdup, the volumetric mass transfer coefficients of toluene and oxygen, and the microbial kinetics were obtained for this model. The substrate inhibition theory was used to simulate the microorganism growth kinetics, and its kinetic constants were obtained experimentally. The penetration theory was used to predict the volumetric mass transfer coefficient. And the drift-flux theory was used to predict the hydrodynamic properties in each section (riser, gas-liquid separator, downcomer, and bottom) of the airlift bioreactor. The concentration distributions of toluene and oxygen in the airlift bioreactor and the removal efficiency of toluene predicted by the mathematical model agreed well with the experimental data.
在内循环气升式生物反应器中利用悬浮微生物处理含甲苯废气。反应器的工作体积为35L，生物质浓度为3kg/m³。气体污染物从底部流入反应器；然后从气相转移到液相，并被液相中悬浮的微生物降解。当甲苯入口浓度为0.5至10g/m³且表观气速范围为0.15至1.23cm/s时，微生物能够降解50 - 90%的入口甲苯。还建立了一个综合数学模型来描述内循环气升式生物反应器中甲苯的整体降解过程。整体降解过程包括气体流动、气液传质、液相的流动和扩散以及微生物动力学。针对该模型获得了包括气体和液体表观速度、气体持液率、甲苯和氧气的体积传质系数以及微生物动力学在内的流体动力学特性。采用底物抑制理论模拟微生物生长动力学，并通过实验获得其动力学常数。采用渗透理论预测体积传质系数。采用漂移通量理论预测气升式生物反应器各部分（上升管、气液分离器、下降管和底部）的流体动力学特性。数学模型预测的气升式生物反应器中甲苯和氧气的浓度分布以及甲苯的去除效率与实验数据吻合良好。
