Department of Civil and Environmental Engineering, Duke University , Box 90287, Durham, North Carolina 27708, United States.
Environ Sci Technol. 2014 Jan 21;48(2):970-6. doi: 10.1021/es403640j. Epub 2014 Jan 10.
Consumer products such as clothing and medical products are increasingly integrating silver and silver nanoparticles (AgNPs) into base materials to serve as an antimicrobial agent. Thus, it is critical to assess the effects of AgNPs on wastewater microorganisms essential to biological nutrient removal. In the present study, pulse and continuous additions of 0.2 and 2 ppm gum arabic and citrate coated AgNPs as well as Ag as AgNO3 were fed into sequencing batch reactors (SBRs) inoculated with nitrifying sludge. Treatment efficiency (chemical oxygen demand (COD) and ammonia removal), Ag dissolution measurements, and 16S rRNA bacterial community analyses (terminal restriction fragment length polymorphism, T-RFLP) were performed to evaluate the response of the SBRs to Ag addition. Results suggest that the AgNPs may have been precipitating in the SBRs. While COD and ammonia removal decreased by as much as 30% or greater directly after spikes, SBRs were able to recover within 24 h (3 hydraulic retention times (HRTs)) and resume removal near 95%. T-RFLP results indicate Ag spiked SBRs were similar in a 16s rRNA bacterial community. The results shown in this study indicate that wastewater treatment could be impacted by Ag and AgNPs in the short term but the amount of treatment disruption will depend on the magnitude of influent Ag.
消费品，如服装和医疗产品，越来越多地将银和银纳米粒子（AgNPs）整合到基础材料中，作为一种抗菌剂。因此，评估 AgNPs 对生物营养去除至关重要的废水微生物的影响至关重要。在本研究中，将 0.2 和 2 ppm 的阿拉伯树胶和柠檬酸钠涂层 AgNPs 以及 Ag 作为 AgNO3 的脉冲和连续添加到接种硝化污泥的序批式反应器（SBR）中。进行处理效率（化学需氧量（COD）和氨去除）、Ag 溶解测量和 16S rRNA 细菌群落分析（末端限制性片段长度多态性，T-RFLP），以评估 SBR 对 Ag 添加的响应。结果表明，AgNPs 可能在 SBR 中沉淀。虽然 COD 和氨去除率在直接添加后直接下降了多达 30%或更多，但 SBR 在 24 小时内（3 个水力停留时间（HRT））恢复并恢复近 95%的去除率。T-RFLP 结果表明，Ag 加标 SBR 在 16s rRNA 细菌群落中相似。本研究结果表明，废水处理可能会在短期内受到 Ag 和 AgNPs 的影响，但处理中断的程度将取决于进水 Ag 的数量。
