Center for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Center for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Sci Total Environ. 2019 Mar 20;657:739-745. doi: 10.1016/j.scitotenv.2018.12.094. Epub 2018 Dec 7.
This study evaluated the removal of diclofenac (DCF) in activated sludge and its long-term exposure effects on the function and structure of the microbial community. Activated sludge could remove <50% of 50 μg/L DCF. The removal decreased significantly to below 15% when DCF concentrations increased to 500 and 5000 μg/L. Quantitative assessment of the fate of DCF showed that its main removal routes were biodegradation (21%) and adsorption (7%), with other abiotic removals being insignificant (<5%). The biodegradation occurred through cometabolic mechanisms. DCF exposure in the range of 50-5000 μg/L did not disrupt the major functions of the activated sludge ecosystem (e.g. biomass yield and heterotrophic activity) over two months of DCF exposure. Consistently, 16S rRNA gene-based community analysis revealed that the overall community diversity (e.g. species richness and diversity) and structure of activated sludge underwent no significant alterations. The analysis did uncover a significant increase in several genera, Nitratireductor, Asticcacaulis, and Pseudacidovorax, which gained competitive advantages under DCF exposure. The enrichment of Nitratireductor, Asticcacaulis, and Pseudacidovorax genus might contribute to DCF biodegradation and emerge as a potential microbial niche for the removal of DCF.
本研究评估了活性污泥对双氯芬酸（DCF）的去除效果及其对微生物群落功能和结构的长期暴露效应。活性污泥可以去除浓度为 50μg/L 的 DCF 的 <50%。当 DCF 浓度增加到 500 和 5000μg/L 时，去除率显著下降至 <15%。对 DCF 归宿的定量评估表明，其主要去除途径是生物降解（21%）和吸附（7%），其他非生物去除途径可以忽略不计（<5%）。生物降解是通过共代谢机制发生的。在长达两个月的 DCF 暴露期间，50-5000μg/L 的 DCF 暴露并未破坏活性污泥生态系统的主要功能（如生物量产量和异养活性）。同样，基于 16S rRNA 基因的群落分析表明，活性污泥的整体群落多样性（如物种丰富度和多样性）和结构没有发生显著变化。分析确实发现了几个属的显著增加，如 Nitratireductor、Asticcacaulis 和 Pseudacidovorax，它们在 DCF 暴露下获得了竞争优势。Nitratireductor、Asticcacaulis 和 Pseudacidovorax 属的富集可能有助于 DCF 的生物降解，并成为去除 DCF 的潜在微生物生态位。
