胞外聚合物中蛋白质对好氧污泥颗粒化的影响

Effect of protein in extracellular polymeric substance on aerobic sludge granulation

为确定胞外聚合物(EPS)中蛋白质(PN)对好氧颗粒污泥(AGS)形成的影响,研究了好氧污泥颗粒化过程,污泥EPS变化规律及其与污泥表面特性的相关性,分析了AGS和接种污泥EPS组分和相关官能团的差异并确定了EPS分布情况。结果表明,在好氧污泥颗粒化期间,EPS中PN含量由13.98 mg·g^(−1)增加到41.86 mg·g^(−1),多糖(PS)含量维持在15.88~26.74 mg·g^(−1),PN与PS的比值(PN/PS)由0.88增加到1.57。PN含量与污泥Zeta电位和污泥表面疏水性(RH)分别呈负相关和正相关,所对应的相关系数(r)分别为0.950和0.934。与接种污泥相比,AGS的EPS中代表酪氨酸和色氨酸类蛋白质的荧光强度增强,并且出现芳香族蛋白和富里酸类物质以及含有N—H官能团的蛋白质。因此,在好氧污泥颗粒化过程中,EPS中PN种类和含量均有所增加,污泥Zeta电位降低,RH升高,对微生物相互聚集形成AGS具有促进作用。

In order to determine the effect of protein(PN)in extracellular polymeric substances(EPS)on the formation of aerobic granular sludge(AGS),the variation of EPS in aerobic sludge granulation process and its correlation with sludge surface characteristics were studied.The differences of EPS components and related functional groups were analyzed between AGS and inoculated sludge,and the distribution of EPS was determined.The results showed that the PN content increased from 13.98 mg·g^(−1) to 41.86 mg·g^(−1),the polysaccharides(PS)content maintained at 15.88~26.74 mg·g^(−1),and the PN/PS ratio(PN/PS)increased from 0.88 to 1.57 during the aerobic sludge granulation.The PN content was negatively correlated with Zeta potential and positively correlated with sludge surface hydrophobicity(RH),with correlation coefficients(r)of 0.950 and 0.934,respectively.Compared with inoculated sludge,the fluorescence intensity of protein representing tyrosine and tryptophan in EPS of AGS increased,and aromatic protein,fulvic acid substance and protein with N—H functional group appeared.Therefore,in the process of aerobic sludge granulation,both the type and content of PN in EPS increased,Zeta potential decreased and RH increased,which promoted the formation of AGS through aggregation of microbes.