Research group EnVOC, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
Research group EnVOC, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Department of Chemical Engineering and Food Technology, Vine and Agri-Food Research Institute (IVAGRO), University of Cadiz, Pol. Río San Pedro s/n, Puerto Real 11510, Cadiz, Spain.
Sci Total Environ. 2023 Dec 15;904:167326. doi: 10.1016/j.scitotenv.2023.167326. Epub 2023 Sep 23.
The emission of volatile organic compounds (VOCs) into the atmosphere causes negative environmental and health effects. Biofiltration is known to be an efficient and cost-effective treatment technology for the removal of VOCs in waste gas streams. However, little is known on the removal of VOC mixtures and the effect of operational conditions, particularly for hydrophobic VOCs, and on the microbial populations governing the biofiltration process. In this study, we evaluated the effect of inoculum type (acclimated activated sludge (A-AS) versus Rhodococcus erythropolis) and packing material (mixture of compost and wood chips (C + WC) versus expanded perlite) on the removal of a mixture of hydrophobic VOCs (toluene, cyclohexane and hexane) in three biofilters (BFs), i.e., BF1: C + WC and R. erythropolis; BF2: C + WC and A-AS; and BF3: expanded perlite and R. erythropolis. The BFs were operated for 374 days at varying inlet loads (ILs) and empty bed residence times (EBRTs). The results showed that the VOCs were removed in the following order: toluene > cyclohexane > hexane, which corresponds to their air-water partitioning coefficient and thus bioavailability of each VOC. Toluene is the most hydrophilic VOC, while hexane is the most hydrophobic. BF2 outperformed BF1 and BF3 in each operational phase, with average maximum elimination capacities (ECmax) of 21 ± 3 g toluene m h (removal efficiency (RE): 100 %; EBRT: 82 s), 11 ± 2 g cyclohexane m h (RE: 86 ± 6 %; EBRT: 163 s) and 6.2 ± 0.9 g hexane m h (RE: 96 ± 4 %; EBRT: 245 s). Microbial analysis showed that despite having different inocula, the genera Rhodococcus, Mycobacterium and/or Pseudonocardia dominated in all BFs but at different relative abundances. This study provides new insights into the removal of difficult-to-degrade VOC mixtures with limited research to date on biofiltration.
挥发性有机化合物（VOCs）排放到大气中会对环境和健康造成负面影响。生物过滤被认为是一种高效且具有成本效益的废气处理技术，可去除 VOCs。然而，对于 VOC 混合物的去除以及操作条件的影响，特别是对于疏水性 VOCs 的影响，以及对控制生物过滤过程的微生物种群的影响，知之甚少。在这项研究中，我们评估了接种物类型（驯化的活性污泥（A-AS）与红球菌（Rhodococcus erythropolis））和包装材料（堆肥和木屑的混合物（C+WC）与膨胀珍珠岩）对三种生物过滤器（BF）中疏水性 VOC 混合物（甲苯、环己烷和己烷）去除的影响，即 BF1：C+WC 和 R. erythropolis；BF2：C+WC 和 A-AS；和 BF3：膨胀珍珠岩和 R. erythropolis。BF 在不同的入口负荷（IL）和空床停留时间（EBRT）下运行了 374 天。结果表明，VOC 按以下顺序去除：甲苯>环己烷>己烷，这与它们的气-水分配系数有关，因此与每个 VOC 的生物利用度有关。甲苯是最亲水的 VOC，而己烷是最疏水的 VOC。在每个操作阶段，BF2 均优于 BF1 和 BF3，最大消除容量（ECmax）分别为 21±3g 甲苯 m h（去除效率（RE）：100%；EBRT：82s）、11±2g 环己烷 m h（RE：86±6%；EBRT：163s）和 6.2±0.9g 己烷 m h（RE：96±4%；EBRT：245s）。微生物分析表明，尽管接种物不同，但在所有 BF 中，优势属为红球菌（Rhodococcus）、分枝杆菌（Mycobacterium）和/或诺卡氏菌（Pseudonocardia），但相对丰度不同。本研究为目前关于生物过滤的研究中有限的难降解 VOC 混合物的去除提供了新的见解。
