Hsieh C C
Department of Environmental and Safety Engineering, National Yunlin University of Science and Technology, Yunlin, 640, Touliu, Taiwan.
J Hazard Mater. 2000 Dec 1;79(1-2):173-87. doi: 10.1016/s0304-3894(00)00259-4.
This study investigated the factors in plant operating parameters effecting volatile organic compound (VOC) removal and elucidated each individual mechanism in an activated sludge process (ASP). The results suggest that stripping increase with an increase in Henry's law constant with the exception of toluene, which differed because of the effect of biodegradation competition. The emission rate can be controlled by increasing the active biomass concentration (X(b)) in the aeration basin, hydraulic retention time (HRT), and oxygen transfer efficiency (OTE). Increasing X(b) enhances total VOC removal and biodegradation, which reduces the fraction of the stripping removal. Longer HRT can reduce stripping removal significantly if other variables such as oxygen requirement and OTE are held constant. For the same volatile compound, a process with higher air-to-water ratio requires a higher active biomass concentration to reduce stripping removal. Increasing OTE decreases the air-to-water ratio requirement, which reduces the gas-phase transfer of VOCs into the atmosphere. The results show a reasonable agreement between measured and predicted stripping values.
本研究调查了影响挥发性有机化合物（VOC）去除的工厂运行参数因素，并阐明了活性污泥法（ASP）中的各个单独机制。结果表明，除甲苯外，随着亨利定律常数的增加，汽提作用增强，甲苯的情况有所不同，这是由于生物降解竞争的影响。可以通过增加曝气池中的活性生物量浓度（X(b)）、水力停留时间（HRT）和氧传递效率（OTE）来控制排放速率。增加X(b)可提高总VOC去除率和生物降解率，从而降低汽提去除的比例。如果其他变量如需氧量和OTE保持不变，较长的HRT可显著降低汽提去除率。对于相同的挥发性化合物，气水比更高的工艺需要更高的活性生物量浓度来降低汽提去除率。增加OTE可降低气水比要求，从而减少VOCs向大气中的气相转移。结果表明，实测汽提值与预测值之间具有合理的一致性。
