Removal Features of DOM in Bio-treated Effluents by Enhanced Coagulation Process

WANG Jingbo1, ZHANG Linnan1,†, LI Zhenshan2

1. Faculty of Science, Shenyang University of Technology, Shenyang 110870; 2. College of Environmental Science and Engineering, Peking University, Beijing 100871; † Corresponding author, E-mail: zln2277@263.net

Abstract Three advanced flocculants were used to treat the biochemical treatment samples extracted from the landfill leachate. In order to explore the transformation characteristics of dissolved organic matter (DOM) in the process of coagulation, all the samples’ DOM from three stages were characterized by ultraviolet-visible spectra (UV-VIS), three dimensional fluorescence spectra (EEM) and Fourier transform ion cyclotron resonance electrospray mass spectrometry (ESI FT-ICR MS). UV-VIS spectra showed that the ratio of small molecules increased in water while both the humification degree and condensation degree reduced after coagulation. EEM suggested that the removal efficiency of protein and humic acid substances were very high after coagulation. FT-ICR MS indicated that there was a strong selectivity of flocculants for the removable DOM in different stages of coagulation. DOM in the final residual water was mainly smaller molecular weight, containing impurity atoms with low unsaturation, O/C<0.3, and H/C>1.5. Key words landfill leachate; biochemical unit effluent; dissolved organic matter (DOM); coagulation

垃圾渗滤液是一种含有大量不易被生物降解的富含有机物的污水, 含腐殖酸和富里酸类等溶解性有机物(dissolved organic matter, DOM)以及高浓度的氨氮、重金属、氯代有机物和无机盐等[1–4]。因

此, 垃圾渗滤液必须经过处理, 达标后才能排放。DOM 在垃圾渗滤液中占很大比例, 约占总有机物的 85%[5–7]。所以, 对于 DOM 的研究具有十分重要的意义。

辽宁省教育厅科学技术研究项目(201764136)资助收稿日期: 2017–03–01; 修回日期: 2017–05–31; 网络出版日期: 2018–05–10