Anoxic biodegradation of BTEX in a biotrickling filter.
Anoxic biodegradation of BTEX in a biotrickling filter.
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DOI：
10.1016/j.scitotenv.2017.02.130
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
Ilker Akmirza;C. Pascual;A. Carvajal;Rebeca Pérez;R. Muñoz;R. Lebrero
中科院分区：
文献类型：
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作者：
Ilker Akmirza;C. Pascual;A. Carvajal;Rebeca Pérez;R. Muñoz;R. Lebrero
石化工业排放的BTEX（苯、甲苯、乙苯和二甲苯）具有污染物浓度低和缺氧的特点。利用硝酸盐作为电子受体对这些污染物进行生物降解是将残余气体用于惰化目的的关键。然而，BTEX的生物矿化往往受到其顽固性和次生代谢产物毒性的限制。本文评估了缺氧生物滴滤池处理进口浓度为~ 700 mg m - 3的无氧btex模型排放的潜力。在生物过滤前的回收液和进口气体排放中也测试了紫外线氧化步骤。甲苯和乙苯的去除率均达到bbb90 %，对应的去除率（ECs）分别为1.4±0.2 g m−3h−1和1.5±0.3 g m−3h−1，而二甲苯的去除率为~ 45% (EC = 0.6±0.1 g m−3h−1)，液体循环速率为2 m h−1。然而，苯的生物降解受到液相中有毒代谢物积累的限制。这些中间体在回收液中的紫外光解氧化促进了苯的减排，平均EC为0.5±0.2 g m−3h−1，去除率为~ 40%。然而，在进气排放中采用UV氧化作为预处理步骤，导致生物滴滤器对BTEX的生物降解能力下降。最后，在整个实验中观察到高度的细菌多样性，主要的门是变形杆菌和热球菌。
Emissions of BTEX (benzene, toluene, ethylbenzene and xylene) from the petrochemical industry are characterized by a low pollutants concentration and the absence of oxygen. Biodegradation of these pollutants using nitrate as the electron acceptor is of key interest to reuse the residual gas for inertization purposes. However, the biological mineralization of BTEX is often limited by their recalcitrant nature and the toxicity of the secondary metabolites produced. The potential of an anoxic biotrickling filter for the treatment of a model O2-free BTEX-laden emission at inlet individual concentrations of ~ 700 mg m− 3was here evaluated. A UV oxidation step was also tested both in the recycling liquid and in the inlet gas emission prior to biofiltration. Removal efficiencies > 90% were achieved for both toluene and ethylbenzene, corresponding to elimination capacities (ECs) of 1.4 ± 0.2 g m− 3h− 1and 1.5 ± 0.3 g m− 3h− 1, respectively, while ~ 45% of xylene (EC = 0.6 ± 0.1 g m− 3h− 1) was removed at a liquid recycling rate of 2 m h− 1. Benzene biodegradation was however limited by the accumulation of toxic metabolites in the liquid phase. The oxidation of these intermediates in the recycling liquid by UV photolysis boosted benzene abatement, achieving an average EC of 0.5 ± 0.2 g m− 3h− 1and removals of ~ 40%. However, the implementation of UV oxidation as a pretreatment step in the inlet gas emission resulted in the deterioration of the BTEX biodegradation capacity of the biotrickling filter. Finally, a high bacterial diversity was observed throughout the entire experiment, the predominant phyla beingProteobacteriaandDeinococcus-thermus.