State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092, PR China.
Water Res. 2020 May 15;175:115705. doi: 10.1016/j.watres.2020.115705. Epub 2020 Mar 14.
Biological treatment of wastewater always leaves plenty of refractory dissolved organic matters (DOM) in effluents, specifically for fresh waste leachate. Aiming at comprehending the production and removal of these compounds, this study investigated DOM transformation in a simultaneous denitrification and methanogenesis with activated sludge (SDM-AS) system with NO/NO backflow for raw fresh leachate. Chemical oxygen demand (COD) was reduced to 854 ± 120 mg/L from 63000 ± 470 mg/L, and total nitrogen (TN) decreased from 2500 ± 647 mg/L to 404 ± 75 mg/L, during an operation of 440 days. The SDM reactor was fed at organic loading rate of 6.70 kgCOD/(m·d) to generate 2.52 L CH/(L·d). Molecular information of leachate DOM was acquired by using ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry. A DOM classification based on Venn diagram was proposed to divide leachate DOM into seven categories. It revealed that 76-84% of final effluent DOM stemmed from biological derivation. Posteriori non-target screening showed anthropogenic micropollutants, e.g. phosphate flame retardants and industrial agents, probably contributed to the remnant native inert DOM in the effluent at the levels of 5-200 μg/L. DOM Classification also showed a portion of bio-derived DOM can be completely removed by SDM-AS processes, while the rest bio-derived DOM can be partially removed depending on DOM nature and the recirculation ratio. The removal and production rate of a specific bio-derived molecule in respective SDM and AS units theoretically satisfied a hyperbolical and dual relationship in terms of mass balance. The persistence of each DOM category was sorted. These results showed anaerobic degradation could be a promising approach to reduce aerobic bio-derived DOM.
废水的生物处理总会在废水中留下大量难处理的溶解有机物（DOM），特别是对于新鲜垃圾渗滤液。本研究旨在了解这些化合物的产生和去除，针对新鲜垃圾渗滤液，采用带有 NO/NO 回流的同步反硝化和产甲烷活性污泥（SDM-AS）系统，研究了 DOM 的转化。在 440 天的运行过程中，化学需氧量（COD）从 63000±470mg/L 降低到 854±120mg/L，总氮（TN）从 2500±647mg/L 降低到 404±75mg/L。SDM 反应器的有机负荷率为 6.70kgCOD/（m·d），产气量为 2.52L CH/（L·d）。采用超高效液相色谱-轨道阱质谱联用技术获取渗滤液 DOM 的分子信息。基于文氏图提出了一种 DOM 分类方法，将渗滤液 DOM 分为七类。结果表明，最终出水 DOM 中有 76-84%来自生物衍生。后续非靶向筛选表明，人为微污染物，如磷酸盐阻燃剂和工业药剂，可能以 5-200μg/L 的水平存在于废水中，对残留的天然惰性 DOM 有贡献。DOM 分类还表明，SDM-AS 工艺可以完全去除一部分生物衍生 DOM，而其余生物衍生 DOM的去除程度取决于 DOM 的性质和回流比。在理论上，特定生物衍生分子在各自的 SDM 和 AS 单元中的去除和产生速率符合质量平衡的双曲线和双重关系。对每个 DOM 类别的持久性进行了排序。这些结果表明，厌氧降解可能是减少好氧生物衍生 DOM 的一种很有前途的方法。
