不同粒径成熟好氧颗粒污泥EPS的三维荧光光谱特性

Three-dimensional Excitation Emission Matrix Fluorescence Spectroscopic Characterization of Extracellular Polymeric Substances of Mature Aerobic Granular Sludge with Different Particle Sizes

为了研究不同粒径成熟好氧颗粒污泥(AGS)中胞外聚合物(EPS)的分布及物理化学特性,探究AGS的最优培养粒径,采用超声结合加热法提取了SBR中8种不同粒径成熟AGS的EPS,并利用三维荧光光谱(3D-EEM)结合化学法对其主要组分进行了定性和定量分析。3D-EEM分析结果显示,随着AGS粒径的不断增大,AGS中蛋白质类的荧光强度逐渐增强,表明蛋白质类物质在大粒径(d>1.25 mm)AGS内分布较多,蛋白质类物质有助于污泥的颗粒化。腐殖酸类物质的荧光强度随着粒径的增大而逐渐减弱,意味着腐殖酸类物质在小粒径AGS中分布较多,表明其可能对AGS的形成影响不大。在AGS的培养过程中,并非粒径越大越好。研究中,不同粒径AGS的蛋白质/多糖在1.6~2.0 mm范围内达到最大,且在此范围内AGS的SVI30值最低,因此可以认为1.6~2.0 mm是AGS的最优粒径。

To investigate the properties of extracellular polymeric substances( EPS) in mature aerobic granular sludge( AGS) with different particle sizes,EPS of AGS with 8 different particle sizes was extracted by ultrasonic wave and heating method. A combination of three-dimensional excitation emission matrix fluorescence spectra(3 D-EEM) and chemical method was applied to analyze the composition of EPS in each particle size. The results of 3 D-EEM showed that the fluorescence intensity of protein in AGS gradually increased with the increasing of AGS particle size,indicating the protein mainly distributed in AGS with larger size particles( d > 1. 25 mm). It also implied that protein( PN) facilitated the sludge granulation. While fluorescence intensity of humus decreased with the increasing of AGS particle size,suggesting that the humic acid substances mainly distributed in the smaller particle size of AGS. It possibly meant that humic acids had little effect on the formation of AGS. In the process of AGS cultivating,bigger particle size of AGS was not necessarily better. In the present study,the PN/polysaccharide( PS)proportion of AGS reached the maximum in the range of 1. 6-2. 0 mm,with which AGS had the lowest SVI30 value. Thus,AGS with the particle size of 1. 6-2. 0 mm was considered to have the most excellent performance.