Cai Min-Hui, Tian Ye-Chao, Li Ai-Min, Li Yan, Han Yu-Ze, Ji Wen-Xiang, Zhou Qing, Li Jun, Li Wen-Tao
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023 Nanjing, China.
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023 Nanjing, China; Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 210094 Nanjing, China.
Water Res. 2023 May 15;235:119879. doi: 10.1016/j.watres.2023.119879. Epub 2023 Mar 13.
Changes in spectral features and molecular weight (MW) of dissolved organic matter (DOM) along the A/A/O processes in eight full-scale wastewater treatment plants (WWTPs) were characterized using size exclusion chromatography with a diode array detector, a fluorescence detector and an organic carbon detector in tandem (SEC-DAD-FLD-OCD) as well as bulk water quality parameters. The parallel factor (PARAFAC) and the nonnegative matrix factorization (NMF) analyses have been effectively applied to the postprocessing of SEC-FLD fingerprints and SEC-OCD chromatograms, respectively. Individual SEC-FLD-PARAFAC or SEC-OCD-NMF components may span a broad range of MW, indicating that these SEC fractions within the same component were cognate and varied coherently across the dataset samples. The SEC-FLD-PARAFAC modeling and SEC-OCD-NMF analysis have clearly and concisely presented that the dramatic decreases of dissolved organic carbon, UV absorbance at 254 nm and protein-like fluorescence at Ex280/Em350 nm in the anaerobic process were primarily associated with the degradation of the large MW proteinaceous and polysaccharide-like biopolymers. It has also revealed that fluorescence of humic acid-like fractions increased significantly during the anaerobic process, but fluorescence of fulvic acid-like and humic substances' building blocks decreased slightly. Laboratory experiments further confirmed the presence of the humification process in anaerobic processes, and the formation of humic acid-like fluorophores may be associated with carbohydrate metabolism. The combination of SEC-FLD-PARAFAC and SEC-OCD-NMF helped to establish the links between changes in bulk water quality parameters and the evolution of SEC MW fractions, which provides a more in-depth insight into wastewater DOM treatability and enables the optimization of wastewater treatment processes.
利用配备二极管阵列检测器、荧光检测器和有机碳检测器的串联尺寸排阻色谱法（SEC-DAD-FLD-OCD）以及总体水质参数，对八个全尺寸污水处理厂（WWTPs）在A/A/O工艺过程中溶解有机物（DOM）的光谱特征和分子量（MW）变化进行了表征。平行因子（PARAFAC）分析和非负矩阵分解（NMF）分析已分别有效地应用于SEC-FLD指纹图谱和SEC-OCD色谱图的后处理。单个SEC-FLD-PARAFAC或SEC-OCD-NMF组分可能涵盖广泛的分子量范围，这表明同一组分内的这些SEC级分是同源的，并且在整个数据集样本中连贯变化。SEC-FLD-PARAFAC建模和SEC-OCD-NMF分析清楚而简洁地表明，厌氧过程中溶解有机碳、254nm处的紫外线吸光度以及Ex280/Em350nm处类蛋白质荧光的显著下降主要与大分子量蛋白质和类多糖生物聚合物的降解有关。研究还表明，类腐殖酸级分的荧光在厌氧过程中显著增加，但类富里酸和腐殖物质结构单元的荧光略有下降。实验室实验进一步证实了厌氧过程中存在腐殖化过程，类腐殖酸荧光团的形成可能与碳水化合物代谢有关。SEC-FLD-PARAFAC和SEC-OCD-NMF的结合有助于建立总体水质参数变化与SEC分子量级分演变之间的联系，这为深入了解废水DOM的可处理性提供了帮助，并能够优化废水处理工艺。
