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Xue S.,Liaoning University | Xue S.,Key Laboratory of Aquatic Environmental Biology and Ecological Security of Liaoning Province | Zhao Q.L.,Harbin Institute of Technology | Wei L.L.,Harbin Institute of Technology | And 4 more authors.
Environmental Technology (United Kingdom) | Year: 2013

The aim of this study was to identify qualitative and quantitative changes in the character of water-extractable organic matter (WEOM) in soils as a consequence of soil aquifer treatment (SAT). Soil samples were obtained from a soil-column system with a 2-year operation, and divided into seven layers from top to bottom: CS1 (0-12.5 cm), CS2 (12.5-25 cm), CS3 (25-50 cm), CS4 (50-75 cm), CS5 (75-100 cm), CS6 (100-125 cm) and CS7 (125-150 cm). A sample of the original soil used to pack the columns was also analysed to determine the effects of SAT. Following 2 years of SAT operation, both soil organic carbon and water-extractable organic carbon were shown to accumulate in the top soil layer (0-12.5 cm), and to decrease in soil layers deeper than 12.5 cm. The WEOM in the top soil layer was characterized by low aromaticity index (AI), low emission humification index (HIX) and low fluorescence efficiency index (F eff. On the other hand, the WEOM in soil layers deeper than 12.5 cm had increased values of HIX and F eff, as well as decreased AI values relative to the original soil before SAT. In all soil layers, the percentage of hydrophobic and transphilic fractions decreased, while that of the hydrophilic fraction increased, as a result of SAT. The production of the amide-2 functional groups was observed in the top soil layer. SAT operation also led to the enrichment of hydrocarbon and amide-1 functional groups, as well as the depletion of oxygen-containing functional groups in soil layers deeper than 12.5 cm. © 2013 Copyright Taylor and Francis Group, LLC.

Xue S.,Liaoning University | Xue S.,Key Laboratory of Aquatic Environmental Biology and Ecological Security of Liaoning Province | Zhao Q.,Harbin Institute of Technology | Wei L.,Harbin Institute of Technology | And 5 more authors.
Environmental Progress and Sustainable Energy | Year: 2015

Jar test experiments were performed to investigate the reductions of dissolved organic matter (DOM) in secondary municipal effluents by coagulation, as well as the effect of coagulation on the structural and functional properties of DOM fractions. The reductions of 9-58% and 17-71% in dissolved organic carbon (DOC) and the removals of 30-75% and 30-83% in absorbance of ultraviolet light at 254 nm (UV-254) were obtained by coagulation of two secondary municipal effluents, respectively. Moreover, the order of DOC and UV-254 removals by coagulation was pH 5 > pH 6 > unadjusted pH at all coagulant dosages. The reductions of the bulk fluorescent materials by coagulation were lower than those of UV-254 absorbing compounds. Among four types of fluorophores, aromatic protein-like fluorophores were preferentially removed by coagulation. The coagulation treatability of hydrophobic acid (HPO-A) was the highest and that of hydrophilic fraction (HPI) was the lowest, among five DOM fractions. In addition, the value of specific ultraviolet light absorbance for each DOM fraction decreased significantly after coagulation. The Fourier-transform infrared spectra revealed that aromatics were effectively removed by coagulation while coagulation seemed to be inefficient in removing amide-2 functional groups and those hydrocarbons exhibiting absorbance characters at 2950-2850 cm-1. © 2014 American Institute of Chemical Engineers Environ Prog.

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