College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai, 201620, China.
College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai, 201620, China.
J Hazard Mater. 2020 Jul 5;393:122407. doi: 10.1016/j.jhazmat.2020.122407. Epub 2020 Feb 25.
Sponge iron (s-Fe) is a potential alternative electron donor for nitrate reduction. To gain insight into the mechanism of denitrification in a constructed wetland- sponge iron coupled system (CW-Fe system), the removal performance and reduction characteristics of nitrate in constructed wetlands (CWs) with and without s-Fe application were compared. Results indicated that s-Fe intensified the removal of nitrate with a 6h-HRT. The nitrate removal efficiency was improved by 16-76 % with various influent NO-N concentrations (10-30 mg L) and at a chemical oxygen demand(COD)/N ratio of 5. The rates of chemical denitrification were positively correlated with the dosage of s-Fe and negatively correlated with the influent COD concentration. 16S rDNA sequencing revealed that hydrogen-utilizing autotrophic denitrifier of Hydrogenophaga was highly enriched (accounting for 10 % of the total OTUs) only in CW-Fe system. The micro-environment created by s-Fe was suitable for heterotrophic denitrifiers of Thauera, Tessaracoccus and Simplicispira. The determination of physiological indicators for plants showed that the application of s-Fe causes abiotic stress to wetland plants (Canna indica L.). Nevertheless, s-Fe can be used as a substrate for CWs, since it allows a high-efficiency removal of nitrate by mediating chemical denitrification and hydrogen-driven autotrophic denitrification.
海绵铁（s-Fe）是一种潜在的硝酸盐还原电子供体替代物。为了深入了解人工湿地-海绵铁耦合系统（CW-Fe 系统）中的反硝化机制，比较了添加和不添加海绵铁的人工湿地（CWs）中硝酸盐的去除性能和还原特性。结果表明，海绵铁强化了硝酸盐的去除，6h-HRT 时硝酸盐去除效率提高了 16-76%。在不同的进水 NO-N 浓度（10-30mg/L）和 COD/N 比为 5 时，硝酸盐去除效率都得到了提高。化学反硝化速率与海绵铁的用量呈正相关，与进水 COD 浓度呈负相关。16S rDNA 测序结果表明，仅在 CW-Fe 系统中高度富集了氢利用自养反硝化菌氢噬菌（占总 OTUs 的 10%）。海绵铁创造的微环境有利于异养反硝化菌陶厄氏菌属、塔氏球菌属和单胞菌属的生长。对植物生理指标的测定表明，海绵铁的应用会对湿地植物（美人蕉）造成非生物胁迫。然而，由于海绵铁可以通过介导化学反硝化和氢驱动自养反硝化来实现硝酸盐的高效去除，因此它可以作为 CWs 的一种基质。
