Profiles of Zeta Potential and EPS in Granulation Process of Aerobic Sludge
好氧污泥颗粒化过程中Zeta电位与EPS的变化特性

The profiles of Zeta potential and EPS, and their correlation were investigated for the aerobic sludge during granulation process. The complete aerobic granular particles were cultivated and grew by controlling operational conditions. During the granulation process, Zeta potential of sludge was decreased from -19.1 mV to -10.1 mV gradually. And it was maintained at a low level-about -10 mV in matured granules, which indicated a low Zeta potential of sludge is an important factor for the development of aerobic granulation of sludge. There was no big variation of polysaccharide in EPS during the granulation, but the protein of EPS was significantly increased, from 13.65 mg·g-1 to 54.12 mg·g-1. The protein/polysaccharide ratio was went up from 0.67 to 3.31.There existed a good correlation between PN/PS ratio and Zeta potential, coefficient 0.849.These results demonstrated the protein of EPS played a significant role on decrease of surface electronic potential, stimulating the growth of sludge aggregation and the formation the aerobic granular sludge.