由于城市生活污水处理厂二级结构出水C/N的影响,人工湿地(CWs)的反硝化效率不令人满意,限制了其在城市生活污水深度处理中的广泛应用。为了解决这个问题,我们构建了增强的CWs,并进行了正交实验来研究不同因素(C/N,填料,和植物)对常规污染物的去除和温室气体(GHG)排放的减少。实验结果表明,C/N为8时,锰砂,最高反硝化效率为85.7%,95.9%,TN为88.6%,NH4+-N,还有COD,分别。在温室气体减排方面,这一组合导致全球变暖潜势最低(176.8毫克/平方米·天),N2O和CH4排放量为0.53和1.25mg/m2·天,分别。填料的表征表明,在锰砂和黄铁矿的表面上形成了磷酸盐的小球形团簇,在黄铁矿的表面上形成了氧化铁晶体。此外,锰砂的表面Mn(II)含量增加了8.8%,黄铁矿上的Fe(III)/Fe(II)和SO42-/S2-分别增加了2.05和0.26,与实验前水平相比。高通量测序表明存在丰富的自养反硝化细菌(硫磺,硫磺,和硫杆菌)在CW中,这解释了增强的CW的反硝化性能。本研究旨在探索增强型CW的高效反硝化和温室气体减排机理。为城市生活污水深度处理提供理论指导。
Owing to the impact of the effluent C/N from the secondary structures of urban domestic wastewater treatment plants, the denitrification efficiency in constructed wetlands (CWs) is not satisfactory, limiting their widespread application in the deep treatment of urban domestic wastewater. To address this issue, we constructed enhanced CWs and conducted orthogonal experiments to investigate the effects of different factors (C/N, fillers, and plants) on the removal of conventional pollutants and the reduction of greenhouse gas (GHG) emission. The experimental results indicated that a C/N of 8, manganese sand, and calamus achieved the best denitrification efficiencies with removal efficiencies of 85.7%, 95.9%, and 88.6% for TN, NH4+-N, and COD, respectively. In terms of GHG emission reduction, this combination resulted in the lowest global warming potential (176.8 mg/m2·day), with N2O and CH4 emissions of 0.53 and 1.25 mg/m2·day, respectively. Characterization of the fillers revealed the formation of small spherical clusters of phosphates on the surfaces of manganese sand and pyrite and iron oxide crystals on the surface of pyrite. Additionally, the surface Mn (II) content of the manganese sand increased by 8.8%, and the Fe (III)/Fe (II) and SO42-/S2- on pyrite increased by 2.05 and 0.26, respectively, compared to pre-experiment levels. High-throughput sequencing indicated the presence of abundant autotrophic denitrifying bacteria (Sulfuriferula, Sulfuritalea, and Thiobacillus) in the CWs, which explains denitrification performance of the enhanced CWs. This study aimed to explore the mechanism of efficient denitrification and GHG emission reduction in the enhanced CWs, providing theoretical guidance for the deep treatment of urban domestic wastewater.