Characterization of persistent colors and decolorization of effluent from biologically treated cellulosic ethanol production wastewater

Shan, Lili; Liu, Junfeng; Yu, Yanling; Ambuchi, John J.; Feng, Yujie

Characterization of persistent colors and decolorization of effluent from biologically treated cellulosic ethanol production wastewater

2016

Shan, Lili | Liu, Junfeng | Yu, Yanling | Ambuchi, John J. | Feng, Yujie

The high chroma of cellulosic ethanol production wastewater poses a serious environmental concern; however, color-causing compounds are still not fully clear. The characteristics of the color compounds and decolorization of biologically treated effluent by electro-catalytic oxidation were investigated in this study. Excitation-emission matrix (EEM), fourier transform infrared spectrometer (FTIR), UV-Vis spectra, and ultrafiltration (UF) fractionation were used to analyze color compounds. High chroma of wastewater largely comes from humic materials, which exhibited great fluorescence proportion (67.1 %) in the biologically treated effluent. Additionally, the color compounds were mainly distributed in the molecular weight fractions with 3–10 and 10–30 kDa, which contributed 53.5 and 34.6 % of the wastewater color, respectively. Further decolorization of biologically treated effluent by electro-catalytic oxidation was investigated, and 98.3 % of color removal accompanied with 97.3 % reduction of humic acid-like matter was achieved after 180 min. The results presented herein will facilitate the development of a well decolorization for cellulosic ethanol production wastewater and better understanding of the biological fermentation.

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