Shao Liming, Deng Yingtao, Qiu Junjie, Zhang Hua, Liu Wanying, Bazienė Kristina, Lü Fan, He Pinjing
Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092, PR China.
Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
Water Res. 2021 May 1;195:117000. doi: 10.1016/j.watres.2021.117000. Epub 2021 Mar 3.
Mature landfill leachate contains a substantial fraction of recalcitrant dissolved organic matters (DOM) that is a challenging for conventional wastewater treatment that is typically focused on the removal of biodegradable organic matter. "Biological treatment + membrane treatment" has been widely employed to treat complex leachate. However, the performance of each unit based on both conventional bulk indicators and molecular information has not been well understood. Therefore, the fate of DOM chemodiversity along the full-scale treatment process across ten sampling points over three different seasons were analyzed to determine the efficiency of every unit process with the assistance of ultra-performance liquid chromatography coupled with hybrid quadrupole Orbitrap mass spectrometry. Results showed that the process performance, visualized through the molecular signals, were relatively stable in the temporal dimension. The process removed 83.2%-92.2% of DOM molecules in terms of richness, where lignin/carboxyl-rich alicyclic compounds (CRAM)-likes with relatively high saturation was preferentially removed, while newly generated bio-derived N-containing compounds (N/C 0.15-0.17) became resistant. The relationship between conventional bulk physicochemical indicators and molecular indexes suggested that soluble chemical oxygen demand (sCOD) and dissolved organic carbon (DOC) were contributed by the refractory DOM with high weighted average double bond equivalents (DBE), which was distributed in the region of O/C 0.2-0.5 and H/C 1.2-1.8. This refractory DOM required ultrafiltration and nanofiltration for removal. DOM molecules were positively correlated with five-day biochemical oxygen demand (BOD) and revealed that approximately 96.9%-98.4% of the DOM could be removed or transformed in the primary anoxic zone. In addition, the bio-derived aliphatic/proteins, lipids and lignin/CRAM-likes (O/C > 0.2) with condensed aromatization were the sources of dissolved organic nitrogen (DON) and still remained in the final effluent. The present study suggests that the design and operation of the combination process with biological and membrane treatment could be specifically optimized based on the DOM molecular characteristics of the wastewater.
成熟垃圾渗滤液含有大量难降解的溶解有机物（DOM），这对通常专注于去除可生物降解有机物的传统废水处理来说是一项挑战。“生物处理 + 膜处理”已被广泛用于处理复杂的渗滤液。然而，基于传统总体指标和分子信息的每个单元的性能尚未得到很好的理解。因此，借助超高效液相色谱与混合四极杆轨道阱质谱联用技术，分析了三个不同季节十个采样点全规模处理过程中DOM化学多样性的去向，以确定每个单元过程的效率。结果表明，通过分子信号可视化的过程性能在时间维度上相对稳定。该过程在丰富度方面去除了83.2% - 92.2%的DOM分子，其中饱和度相对较高的类木质素/富含羧基的脂环族化合物（CRAM）优先被去除，而新生成的生物源含氮化合物（N/C 0.15 - 0.17）变得具有抗性。传统总体理化指标与分子指标之间的关系表明，可溶性化学需氧量（sCOD）和溶解有机碳（DOC）由具有高加权平均双键当量（DBE）的难降解DOM贡献，其分布在O/C 0.2 - 0.5和H/C 1.2 - 1.8区域。这种难降解DOM需要超滤和纳滤来去除。DOM分子与五日生化需氧量（BOD）呈正相关，表明约96.9% - 98.4%的DOM可在初级缺氧区被去除或转化。此外，具有缩合芳构化的生物源脂肪族/蛋白质、脂质和木质素/CRAM类物质（O/C > 0.2）是溶解有机氮（DON）的来源，并且仍残留在最终出水中。本研究表明，生物和膜处理组合工艺的设计和运行可基于废水的DOM分子特征进行具体优化。
