盐度变化对厌氧污泥胞外聚合物的影响

为探讨盐度变化对厌氧污泥胞外聚合物的影响,采用三维荧光(3D-EEM)和傅里叶变换红外(FTIR)技术,研究了不同盐度下升流式厌氧污泥流化床(UASB)中污泥的松散结合型胞外聚合物(LB-EPS)与紧密结合型胞外聚合物(TB-EPS)的变化规律,并分析了LB-EPS和TB-EPS与污泥沉降性间的关系.结果表明,进水盐度由0逐渐增加至8%,厌氧污泥LB-EPS和TB-EPS含量分别由4.94和12.25 mg·g~(-1)(以VSS计)增加至41.47和43.04 mg·g~(-1)(以VSS计);LB-EPS和TB-EPS中蛋白(PN)和多糖(PS)含量的比值分别由3.2和3.8降低至1.8和2.3;污泥容积指数(SVI)与LB-EPS、TB-EPS均正相关;3D-EEM光谱显示,色氨酸蛋白和芳环蛋白荧光峰存在于不同盐度下LB-EPS和TB-EPS中,类胡敏酸荧光峰仅存在于盐度高于4%的TB-EPS中;FTIR分析表明,进水盐度的增加导致LB-EPS和TB-EPS中PS的C—O组分相对含量增加.

Effect of salinity on extracellular polymeric substances of anaerobic sludge

The effect of salinity on the loosely bound extracellular polymeric substances (LB-EPS) and tightly bound extracellular polymeric substances (TB-EPS) from anaerobic sludge in an upflow anaerobic sludge blanket (UASB) reactor was investigated using three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy and Fourier transform infrared (FTIR) spectra. The relationships of the LB-EPS and TB-EPS with sludge volume index (SVI) at different salinities were analyzed. As the increase of influent salinity from 0 to 8%, the LB-EPS and TB-EPS from anaerobic sludge increased from 4.94 and 12.25 mg·g^-1 VSS to 41.47 and 43.04 mg·g^-1 VSS, respectively, and the protein/polysaccharide (PN/PS) ratios in the LB-EPS and TB-EPS decreased from 3.2 and 3.8 to 1.8 and 2.3, respectively. Both the LB-EPS and TB-EPS exhibited positive correlations with SVI. 3D-EEM fluorescence spectroscopy results show that the tryptophan and aromatic protein-like peaks were present in the LB-EPS and TB-EPS at 0~8% salinity, however the humic acid-like peak was only found in the TB-EPS at 4%~8% salinity. Results of FTIR spectrometry exhibit that the increase of influent salinity resulted in the increase of the relative contents of C-O groups of polysaccharide.