[Spectroscopic characterization indicator of landfill in the process of stabilizing]

In the present study, dissolved organic matter (DOM) extracted from landfill of four different ages was studied with fluorescence and ultraviolet-visible spectroscopy in order to explore the possibility of using spectral characteristic changes of DOM as stabilization indicators for landfill. The three-dimensional fluorescence excitation-emission matrix spectroscopy (EEM) displayed that DOM of 0-year-old contained mainly protein-like matter, while DOM extracted from 1, 5 and 10-year-old consisted chiefly of humic matter-like substance, and the intensity change of DOM of 1, 5 and 10-year-old landfill was disordered. Besides, the fluorescence spectroscopy also showed that the r(A,C) value and the fluorescence index f(450/500) of DOM of four different years both decreased with landfill age, which indicated that the low molecular weight fraction of DOM was translated into the high molecular aromatic matter and the degree of humification was enhanced with the time increasing. In addition, the specific ultraviolet-visible absorbance (SUVA) increased with landfill age, which also revealed the law that the degree of humification strengthened with the time increasing, but the change regularity of E4/E6 value of DOM was unconspicuous since the E4/E6 value was easily impacted by some other factors. Therefore, the r(A,C) value, the fluorescence index f(450/500) and the SUVA value of DOM extracted from aged refuse reflected effectively the law of how landfill changed, and could be employed as simple stabilization indicators for aged refuse and closed landfill compartments.