来自废物压缩站点的新鲜渗滤液(FL)中的有机物(OM)和氮构成环境和健康风险。即使人工湿地(CW)可以有效地去除这些污染物,FL中溶解OM(DOM)的分子水平转化仍不确定。这项研究报告了CW中FL处理期间DOM和脱氮的分子动力学。采用了两个实验室规模的垂直流CW系统:一个仅使用沙子作为基质(作为对照,CW-C)和另一种使用锰矿石粉和沙子的相等混合物(实验,CW-M)。超过488天的手术,CW-M对化学需氧量(COD)的去除率明显更高,氨氮(NH4+-N),和溶解的有机物(以溶解的有机碳表示,DOC)为98.2±2.5%,99.2±1.4%,和97.9±1.9%,分别,与CW-C(92.8±6.8%,77.1±28.1%,和74.7±9.5%)。三维荧光激发发射矩阵(3D-EEM)和傅立叶变换离子回旋共振质谱(FT-ICRMS)分析揭示,进水DOM主要由易于生物降解的蛋白质样物质组成,具有高碳含量和低不饱和度。在整个治疗过程中,它导致低O/C和高H/C化合物的降解,导致形成具有较高不饱和度和芳香性的DOM,类似腐殖质的物质。CW-M展示了独特的DOM组成,碳含量较低,但不饱和度和芳香性高于CW-C。该研究还确定了γ变形杆菌的存在,据报道,锰氧化细菌在CW-M的上层和中层中具有明显更高的丰度,促进锰循环和提高DOM去除。有助于DOM去除的关键途径包括吸附,锰氧化物催化氧化,和微生物降解。这项研究为CW治疗期间DOM转换和从FL中去除提供了新的见解,这将有助于更好的设计和提高性能。
The organic matter (OM) and nitrogen in Fresh leachate (FL) from waste compression sites pose environmental and health risks. Even though the constructed wetland (CW) can efficiently remove these pollutants, the molecular-level transformations of dissolved OM (DOM) in FL remain uncertain. This study reports the molecular dynamics of DOM and nitrogen removal during FL treatment in CWs. Two lab-scale vertical-flow CW systems were employed: one using only sand as substrates (act as a control, CW-C) and the other employing an equal mixture of manganese ore powder and sand (experimental, CW-M). Over 488 days of operation, CW-M exhibited significantly higher removal rates for chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and dissolved organic matter (represented by dissolved organic carbon, DOC) at 98.2 ± 2.5%, 99.2 ± 1.4%, and 97.9 ± 1.9%, respectively, in contrast to CW-C (92.8 ± 6.8%, 77.1 ± 28.1%, and 74.7 ± 9.5%). The three-dimensional fluorescence excitation-emission matrix (3D-EEM) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses unveiled that the influent DOM was predominantly composed of readily biodegradable protein-like substances with high carbon content and low unsaturation. Throughout treatment, it led to the degradation of low O/C and high H/C compounds, resulting in the formation of DOM with higher unsaturation and aromaticity, resembling humic-like substances. CW-M showcased a distinct DOM composition, characterized by lower carbon content yet higher unsaturation and aromaticity than CW-C. The study also identified the presence of Gammaproteobacteria, reported as Mn-oxidizing bacteria with significantly higher abundance in the upper and middle layers of CW-M, facilitating manganese cycling and improving DOM removal. Key pathways contributing to DOM removal encompassed adsorption, catalytic oxidation by manganese oxides, and microbial degradation. This study offers novel insights into DOM transformation and removal from FL during CW treatment, which will facilitate better design and enhanced performance.