Untangling the nitrate removal pathways for a constructed wetland-sponge iron coupled system and the impacts of sponge iron on a wetland ecosystem
Untangling the nitrate removal pathways for a constructed wetland-sponge iron coupled system and the impacts of sponge iron on a wetland ecosystem
复制标题
阐明人工湿地-海绵铁耦合系统的硝酸盐去除途径以及海绵铁对湿地生态系统的影响
DOI：
10.1016/j.jhazmat.2020.122407
复制
发表时间：
2020
影响因子：
13.6
通讯作者：
Wolfgang
中科院分区：
文献类型：
--
作者：
Si Zhihao;Song Xinshan;Wang Yuhui;Cao Xin;Wang Yifei;Zhao Yufeng;Ge Xiaoyan;S;Wolfgang
海绵铁(S-Fe0)是一种潜在的硝酸盐还原的替代电子供体。为深入了解人工湿地-海绵铁耦合系统(CW-FeO)的反硝化机理，比较了投加S-FeO前后人工湿地对硝酸盐氮的去除性能和还原特性。结果表明，S-FeO强化了6h水力停留时间对硝酸盐的去除。在不同进水−-N浓度(10~30 mg L-1)和化学需氧量/N比为5时，硝酸盐氮的去除效率提高了16~76%。化学反硝化速率与S-FeO投加量呈正相关，与进水COD浓度呈负相关。16S rDNA测序表明，仅在CW-Fe0体系中，氢噬菌氢利用自养反硝化菌高度浓缩(占总OTUS的10%)。S-Fe0所创造的微环境适合于异养反硝化细菌--水母、水蚤和单胞藻的生长。对植物生理指标的测定表明，S-FeO对湿地植物(美人掌)造成非生物胁迫。然而，S-Fe0可以作为水煤浆的基质，因为它可以通过介导化学反硝化和氢驱动的自养反硝化来高效地去除硝酸盐。
Sponge iron (s-Fe0) 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-Fe0system), the removal performance and reduction characteristics of nitrate in constructed wetlands (CWs) with and without s-Fe0application were compared. Results indicated that s-Fe0intensified the removal of nitrate with a 6h-HRT. The nitrate removal efficiency was improved by 16–76 % with various influent NO3−-N concentrations (10–30 mg L-1) and at a chemical oxygen demand(COD)/N ratio of 5. The rates of chemical denitrification were positively correlated with the dosage of s-Fe0and negatively correlated with the influent COD concentration. 16S rDNA sequencing revealed that hydrogen-utilizing autotrophic denitrifier ofHydrogenophagawas highly enriched (accounting for 10 % of the total OTUs) only in CW-Fe0system. The micro-environment created by s-Fe0was suitable for heterotrophic denitrifiers ofThauera,TessaracoccusandSimplicispira. The determination of physiological indicators for plants showed that the application of s-Fe0causes abiotic stress to wetland plants (Canna indicaL.). Nevertheless, s-Fe0can 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.