School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 20092, PR China; Shanghai Engineering Research Center of Landscape Water Environment, Shanghai, 200031, PR China.
J Environ Manage. 2022 Dec 15;324:116326. doi: 10.1016/j.jenvman.2022.116326. Epub 2022 Sep 28.
Iron-based ecological floating beds (EFBs) are often used to treat the secondary effluent from wastewater treatment plant to enhance the denitrification process. However, the impact and necessity of plants on iron-based EFBs have not been systematically studied. In this research, two iron-based EFBs with and without plants (EFB-P and EFB) were performed to investigate the response of plants on nutrient removal, GHG emissions, microbial communities and functional genes. Results showed the total nitrogen and total phosphorus removal in EFB-P was 45-79% and 48-72%, respectively, while that in EFB was 31-67% and 44-57%. Meanwhile, plants could decrease CH emission flux (0-3.89 mg m d) and improve CO absorption (4704-22321 mg m d). Plants could increase the abundance of Nitrosospira to 1.6% which was a kind of nitrifying bacteria dominant in plant rhizosphere. Among all denitrification related genera, Simplicispira (13.08%) and Novosphingobium (6.25%) accounted for the highest proportion of plant rhizosphere and iron scrap, respectively. Anammox bacteria such as Candidatus_Brocadia was more enriched on iron scraps with the highest proportion was 1.21% in EFB-P, and 2.20% in EFB. Principal co-ordinates analysis showed that plants were the critical factor determining microbial community composition. TN removal pathways were mixotrophic denitrification and anammox in EFB-P while TP removal pathways were plant uptake and phosphorus-iron coprecipitation. In general, plants play an important directly or indirectly role in iron-based EFBs systems, which could not only improve nutrients removal, but also minimize the global warming potential and alleviate the greenhouse effect to a certain extent.
铁基生态浮床（EFB）常用于处理污水处理厂的二级出水，以增强脱氮过程。然而，植物对铁基 EFB 的影响和必要性尚未得到系统研究。本研究采用有无植物的两种铁基 EFB（EFB-P 和 EFB），研究植物对养分去除、温室气体排放、微生物群落和功能基因的响应。结果表明，EFB-P 的总氮和总磷去除率分别为 45-79%和 48-72%，而 EFB 的去除率分别为 31-67%和 44-57%。同时，植物可以降低 CH 排放通量（0-3.89mgm d）和提高 CO 吸收（4704-22321mgm d）。植物可以增加硝化菌在植物根际中的优势地位，将 Nitrosospira 的丰度提高到 1.6%。在所有与脱氮相关的属中，Simplicispira（13.08%）和 Novosphingobium（6.25%）分别在植物根际和铁屑中的比例最高。厌氧氨氧化菌如 Candidatus_Brocadia 在铁屑中更为丰富，EFB-P 中的最高比例为 1.21%，EFB 中的最高比例为 2.20%。主坐标分析表明，植物是决定微生物群落组成的关键因素。EFB-P 中 TN 的去除途径为混合营养型反硝化和厌氧氨氧化，TP 的去除途径为植物吸收和磷铁共沉淀。总的来说，植物在铁基 EFB 系统中发挥着重要的直接或间接作用，不仅可以提高养分去除率，而且可以在一定程度上减少温室气体排放潜力，缓解温室效应。
