Novel insights into variation of fluorescent dissolved organic matters during antibiotic wastewater treatment by excitation emission matrix coupled with parallel factor analysis and cosine similarity assessment

摘要

In this work, the variation of fluorescent dissolved organic matters (FDOM) of antibiotic wastewater in a full-scale treatment plant was studied. Fluorescent components of anaerobic, aerobic, Fenton stages were separately figured out by parallel factor analysis (PARAFAC) based on excitation emission matrix (EEM) dataset. Then, these components were pairwise quantitatively compared according to cosine similarity (CS). It was found that, after the anaerobic treatment, the major components showed remarkable similarity (CS 0.97) to those of raw wastewater, although their maximum fluorescence intensity (F-max) decreased slightly or moderately (7% similar to 54%). However, the aerobic treatment dramatically changed both the composition and content of fluorescent components, as all the protein-like components completely disappeared and only the humic-like components with much lower intensity were observed. After Fenton oxidation, all these humic-like components were remained (CS 0.97) with fairly reduced F-max (51% similar to 61%). For both aerobically treated and Fenton-oxidized wastewater, F-max correlated well with dissolved organic carbon (DOC). This suggested a dominant proportion of humic-like substances. The combination of PARAFAC based on separate EEM dataset of each treatment stage and CS assessment is a good approach to better understand FDOM variation and can be of much practical significance to monitor wastewater quality. (C) 2018 Elsevier Ltd. All rights reserved.