title: [Excitation-emission matrix fluorescence spectra characteristics of DOM in a subsurface constructed wetland for advanced treatment of municipal sewage plant effluent].
abstract: Composition and dynamics of dissolved organic matter (DOM) were analyzed in a horizontal subsurface constructed wetland for advanced treatment of municipal sewage plant effluent using three-dimensional excitation emission matrix fluores cence spectroscopy (3D-EEM). The results indicate that the two subsurface constructed wetlands performed excellent purification of organic substances, and the removal rates of COD(cr), and DOC were 61.6% and 70.1%, respectively. The constructed wetland system filled with ceramsite showed slightly greater removal efficiency of organic substance than that with zeolite substrate. Four different types of peaks such as aromatic protein-like compounds (S), soluble microbial byproducts (T), fulvic acid-like compounds, visible fulvic-like (M) and UV fulvic-like compounds (A) were found in DOM from inflow and outflow of the subsurface wetlands based on the three-dimensional fluorescence spectroscopy analysis. The fluorescence intensity of the four peaks was significantly decreased in the effluent after purification by the subsurface constructed wetlands. Especially, the visible fulvic-like compounds and soluble microbial byproducts were effectively removed from the sewage plant effluent by the subsurface constructed wetland with fluorescence intensity reduction percentages of 16.4% and 11.7%. Aromatic structures of humic-like compounds were weakened and organic compounds with benzene rings were decreased in the outflow of the subsurface constructed wetland. This indicates that the subsurface constructed wetlands can decompose the chemically stable and biorefractory humic-like compounds. The fluorescence intensity of M and T peaks decreased along distance, while the fluorescence intensity of S peaks firstly increased, then decreased along the distance of the subsurface constructed wetlands. As compared to zeolite substrate constructed wetland system, the constructed wetland system filled with ceramsite was more effective to reduce the fluorescence intensity of characterized peaks of DOM from the sewage plant effluent.
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze Water Environment of Ministry of Education, Tongji University, Shanghai 200092, China. cmyang@tongji.edu.cn
authors.forename: Chang-ming
authors.initials: CM
authors.lastname: Yang
authors.forename: Meng-meng
authors.initials: MM
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Ma
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Li