Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Shandong Provincial Key Laboratory of Marine Environmental Geology Engineering, Ocean University of China, Qingdao 266100, China.
Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2022 Oct 10;842:156670. doi: 10.1016/j.scitotenv.2022.156670. Epub 2022 Jun 11.
Anaerobic ammonium oxidation (anammox) is a promising technology applied to treat industrial wastewater, while the commonly coexistent heavy metals and salinity usually become a challenging issue to be addressed. In this study, the responses of anammox sludge in terms of performance, activity, functional enzyme and extracellular polymeric substance (EPS) to the combined stress of Ni(II) and salinity (20 ‰) were investigated holistically. It turned out that low Ni(II) concentration (0.2 mg·L) together with salinity (20 ‰) showed an insignificant effect on the anammox performance, while a decreased nitrogen removal by 46.96 % was observed with the increased Ni(II) concentration to 1 mg·L. It should be pointed out that the anammox system exhibited good robustness evidenced by rapid recovery to achieve 89.13 % of nitrogen removal efficiency and 1.21 kg·m·d of nitrogen removal rate after the elimination of stress factors within 40 days. Ni(II) concentration was revealed to play a more important role in the specific activity of anammox sludge. The functional enzymes related to nitrogen removal, e.g. nitrite reductase (NIR), hydrazine oxidase (HZO) and heme c were found to be inhibited by the combined stress of Ni(II) and salinity, with decreased activity by 49.54 %, 39.39 % and 45.88 %, respectively. However, the enzyme related to assimilation, e.g. alkaline phosphatase (AKP) and nitrate reductase (NAR) appeared to be enhanced. The EPS content was found to decrease by 55.19 % under the combined stress. Detailed analysis of 3D-EEM and FTIR spectra further revealed that the combined stress of Ni(II) and salinity could change both the quantity and composition of EPS in anammox sludge. These results are expected to offer insights into the combined effect of nickel and salinity on the anammox system, and benefit the application of anammox technology for industrial metal-rich saline wastewater treatment.
厌氧氨氧化（anammox）是一种有应用前景的处理工业废水的技术，而通常共存的重金属和盐度通常成为需要解决的挑战。在这项研究中，全面研究了 anammox 污泥在性能、活性、功能酶和胞外聚合物（EPS）方面对 Ni(II)和盐度（20‰）联合胁迫的响应。结果表明，低浓度 Ni(II)（0.2 mg·L）与盐度（20‰）联合作用对 anammox 性能没有显著影响，而当 Ni(II)浓度增加到 1 mg·L 时，氮去除率下降了 46.96%。值得指出的是，anammox 系统表现出良好的鲁棒性，在 40 天内消除胁迫因素后，快速恢复到 89.13%的氮去除效率和 1.21 kg·m·d 的氮去除速率。研究表明，Ni(II)浓度对 anammox 污泥比活度的影响更为重要。与氮去除相关的功能酶，如亚硝酸盐还原酶（NIR）、肼氧化酶（HZO）和血红素 c 被发现被 Ni(II)和盐度的联合胁迫抑制，活性分别降低了 49.54%、39.39%和 45.88%。然而，与同化相关的酶，如碱性磷酸酶（AKP）和硝酸盐还原酶（NAR）似乎增强了。在联合胁迫下，EPS 含量下降了 55.19%。3D-EEM 和 FTIR 光谱的详细分析进一步表明，Ni(II)和盐度的联合胁迫可以改变 anammox 污泥中 EPS 的数量和组成。这些结果有望为深入了解镍和盐度对 anammox 系统的联合影响提供依据，并有助于 anammox 技术在处理富含金属的工业含盐废水方面的应用。
