1. State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
2. Research Center of Environmental Technology in Pollution Source Identification and Precise Supervision, School of Environment, Tsinghua University, Beijing 100084, China
3. Research and Development Center of Advanced Environmental Supervision Technology and Instrument, Research Institute for Environmental Innovation (Suzhou), Tsinghua, Suzhou 215151, China
4. Jiangyin Environmental Monitoring Station, Jiangyin 214433, China
Abstract：Textile printing and dyeing is one of the major industrial sectors in Jiangyin City, Jiangsu Province and textile wastewater was received by many wastewater treatment plants (WWTPs) in Jiangyin City. Dissolved organic matter (DOM) was the major removal target during the wastewater treatment process. Due to fast and convenient measurement, high sensitivity and moderate selectivity, excitation-emission matrix (EEM) has been extensively used to characterize DOM in various water bodies. In this study, the DOM components of the effluents from the main WWTPs in Jiangyin were investigated by EEM. The SUV254 values of the effluents were 1.42～5.71 L·(mg·m)-1, which indicated higher aromaticity than treated municipal wastewater. The effluents generally exhibited two protein-like fluorophores. The protein-like fluorescence intensity per unit of DOC of the effluents from the WWTPs employing biological or “biological + coagulation” process (>2.86 R. U.·L·mg-1) was much higher than that of the effluents from the WWTPs with strong oxidation process (<0.60 R. U.·L·mg-1), which was ascribed to the decomposition of aromatic structure of protein-like fluorescent DOM by strong oxidation. The effluents from about 33% of the WWTPs showed humic-like fluorescence with a higher humification index than the effluents from the other WWTPs. Two parallel factor analysis obtained two protein-like components with the peaks at 225, 280/320 nm and 230, 285/340 nm and one humic-like component with the peak at 240/415 nm. These protein-like fluorophores could be mainly ascribed to Dispersant MF, a kind of common commercial dye additives to improve the dispersion performance of vat and disperse dyes. The main components of Dispersant MF are the formaldehyde condensates of sulfonated washing oil, which are poorly biodegradable. The findings of this work contributed to a profound understanding of the DOM composition in the effluents from the WWTPs in Jiangyin, which was significant to optimization of the treatment process and development of advanced treatment process.
Key words：Effluents from the WWTPs; Textile wastewater; Dissolved organic matter; Excitation emission matrix
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