胞外多聚物在厌氧污泥颗粒化成核过程中的特性

Characteristics of extracellular polymeric substances on nucleation of anaerobic granular sludge

以模拟啤酒废水为底物在IC反应器中进行厌氧污泥颗粒化培养,并对污泥颗粒化过程中胞外多聚物(EPS)的主要成分变化及其与细胞表面疏水性和Zeta电位之间的相互关系进行分析,以此来阐述EPS对污泥颗粒化成核的作用。研究结果表明,好氧剩余污泥在经过56 d的培养后,平均粒径由接种时的54.72μm增长到103.46μm,实现了厌氧污泥颗粒化成核过程;EPS蛋白质含量(PN)在颗粒化过程中逐渐由接种时的18.1 mg/g增至54.3 mg/g,而EPS多糖含量(PS)则无明显变化;此外,PN/PS与污泥平均粒径、细胞表面疏水性(RH)以及Zeta电位之间呈正相关关系,相关系数分别为0.9727、0.9593和0.9274。由此可推测:厌氧污泥颗粒化成核过程的主要作用成分为胞外蛋白质,其可以改变污泥细胞表面疏水性和Zeta电位,从而在厌氧污泥颗粒化过程中有着重要的促进作用。

The cultivation of anaerobic granular sludge with simulated beer wastewater in IC reactor was investigated. The relationships among EPS composition and the average particle size,cell surface hydrophobicity and Zeta potential were analyzed during the cultivation process,by which the effects of extracellular polymeric substances( EPS) on the nucleation of anaerobic sludge were further discussed. Results showed that the nucleation of anaerobic sludge could be achieved after 56 days cultivation process,and the average size of sludge particle increased from 54. 72 μm to 103. 46 μm. The EPS protein content( PN) gradually increased from 18. 1 mg /g to54. 3 mg /g in the nucleation process,while the EPS polysaccharide content( PS) show little variation. Furthermore,the PN /PS ratio was found to be positively correlated with the average particle size,cell surface hydrophobicity( RH) and Zeta potential. The correlation coefficients were 0. 9727,0. 9593 and 0. 9274,respectively. Base on the above results,we proposed that EPS protein was a dominant factor during the nucleation process. The functional factor could adjust the cell surface hydrophobicity( RH) and Zeta potential,and therefore could promote the formation of anaerobic granular sludge.