Jewell Kevin S, Falås Per, Wick Arne, Joss Adriano, Ternes Thomas A
Federal Institute of Hydrology, Am Mainzer Tor 1, 56068, Koblenz, Germany.
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland.
Water Res. 2016 Nov 15;105:559-567. doi: 10.1016/j.watres.2016.08.002. Epub 2016 Aug 8.
The biotransformation of diclofenac during wastewater treatment was investigated. Attached growth biomass from a carrier-filled compartment of a hybrid-MBBR at the wastewater treatment plant (WWTP) in Bad Ragaz, Switzerland was used to test the biotransformation. Laboratory-scale incubation experiments were performed with diclofenac and carriers and high-resolution LC-QTof-MS was implemented to monitor the biotransformation. Up to 20 diclofenac transformation products (TPs) were detected. Tentative structures were proposed for 16 of the TPs after characterization by MS fragmentation and/or inferring the structure from the transformation pathway and the molecular formula given by the high resolution ionic mass. The remaining four TPs were unambiguously identified via analytical reference standards. The postulated reactions forming the TPs were: hydroxylation, decarboxylation, oxidation, amide formation, ring-opening and reductive dechlorination. Incubation experiments of individual TPs, those which were available as reference standards, provided a deeper look into the transformation pathways. It was found that the transformation consists of four main pathways but no pathway accounted for a clear majority of the transformation. A 10-day monitoring campaign of the full-scale plant confirmed an 88% removal of diclofenac (from approximately 1.6 μg/L in WWTP influent) and the formation of TPs as found in the laboratory was observed. One of the TPs, N-(2,6-dichlorophenyl)-2-indolinone detected at concentrations of around 0.25 μg/L in WWTP effluent, accounting for 16% of the influent diclofenac concentration. The biotransformation of carriers was compared to a second WWTP not utilising carriers. It was found that in contact with activated sludge, similar hydroxylation and decarboxylation reactions occurred but at much slower rates, whereas some reactions, e.g. reductive dechlorination, were not detected at all. Finally, incubation experiments were performed with attached growth biomass from a third WWTP with a similar process configuration to Bad Ragaz WWTP. A similarly effective removal of diclofenac was found with a similar presence of TPs.
研究了双氯芬酸在废水处理过程中的生物转化。使用来自瑞士巴德拉加兹污水处理厂(WWTP)混合移动床生物膜反应器(MBBR)中载体填充隔室的附着生长生物量来测试生物转化。用双氯芬酸和载体进行了实验室规模的培养实验,并采用高分辨率液相色谱-四极杆飞行时间质谱(LC-QTof-MS)监测生物转化。检测到多达20种双氯芬酸转化产物(TPs)。通过质谱裂解表征和/或根据转化途径以及高分辨率离子质量给出的分子式推断结构后,为其中16种TPs提出了暂定结构。其余4种TPs通过分析参考标准明确鉴定。推测形成TPs的反应有:羟基化、脱羧、氧化、酰胺形成、开环和还原脱氯。对作为参考标准可用的单个TPs进行的培养实验,更深入地了解了转化途径。发现转化由四个主要途径组成,但没有一个途径占转化的明显多数。对该全尺寸工厂进行的为期10天的监测活动证实,双氯芬酸的去除率为88%(污水处理厂进水约1.6μg/L),并且观察到了实验室中发现的TPs的形成。其中一种TPs,N-(2,6-二氯苯基)-2-吲哚酮,在污水处理厂出水浓度约为0.25μg/L,占进水双氯芬酸浓度的16%。将载体的生物转化与第二个未使用载体的污水处理厂进行了比较。发现与活性污泥接触时,发生了类似的羟基化和脱羧反应,但速率要慢得多,而一些反应,如还原脱氯,根本未检测到。最后,用来自第三个污水处理厂、工艺配置与巴德拉加兹污水处理厂相似的附着生长生物量进行了培养实验。发现双氯芬酸的去除效果相似,TPs的存在情况也相似。