好氧污泥强化造粒过程中EPS的分布及变化规律

发布时间：2018-09-10 10:44

【摘要】：本试验通过在好氧颗粒污泥生长前期投加混凝剂的方式,考察混凝剂的投加对颗粒生长的影响,比较在颗粒生长过程中污泥外观形态及其基本特性的区别,测定整个过程中污泥的细胞表面相对疏水性及Zeta电位,并用三维荧光光谱法分析胞外多聚物(EPS)在颗粒生长过程中的变化规律及其与污泥特性的相关性。研究结果如下:(1)投加混凝剂PAC的反应器里培养的好氧污泥颗粒生成时间和完全颗粒化时间分别比未投加的反应器提前3d和12d,其强度和比重也分别比对照组高出2.05%和0.032,混凝强化造粒条件下形成的颗粒污泥外形规则、结构密实,且沉降絮凝性能均高于对照组。(2)反应器R1中的颗粒污泥完全颗粒化后的细胞表面疏水性维持在75%左右,Zeta电位也稳定在-11m V左右,高于没有投加PAC的反应器中的污泥细胞表面疏水性和Zeta电位,但污泥的表面疏水性和Zeta电位的变化都表现出相同的趋势,且可以明显看出R1的Zeta电位值的上升速率比未投加PAC的R2迅速。(3)对混凝强化造粒条件下颗粒污泥的各形态EPS三维荧光光谱分析发现,生长期松散型胞外多聚物(LB-EPS)的峰点为溶解性微生物代谢产物,及少量的芳香蛋白类物质和腐殖酸类物质,颗粒成熟后溶解性微生物代谢产物和蛋白类物质的荧光强度均减小,腐殖酸类物质消失,而溶解型胞外多聚物(S-EPS)和紧密型胞外多聚物(TB-EPS)的峰点及强度在两阶段无明显变化。(4)分析好氧颗粒污泥形成过程中EPS的含量变化发现,S-EPS含量和TB-EPS含量在整个过程中无明显规律,而LB-EPS含量随颗粒生长逐渐升高,颗粒成熟后逐渐降低至稳定,其中的主要成分蛋白质含量和LB-EPS含量变化趋势基本相同,而多糖含量基本保持在1-5 mg/g MLSS。(5)LB-EPS与S-EPS和TB-EPS相比,与好氧污泥颗粒化的关系有非常密切的关系。LB-EPS与好氧颗粒污泥的SVI有较强的线性相关性,其相关系数为:r=0.812。而LB-EPS中的PN含量与好氧污泥相对疏水性及其Zeta电位也有一定的相关性,其相关系数分别为:r=-0.996和r=-0.937。
[Abstract]:In this experiment, the effect of coagulant on the growth of aerobic granular sludge was investigated by adding coagulant in the early stage of the growth of aerobic granular sludge, and the difference of the appearance and basic characteristics of sludge in the process of granular growth was compared. The relative hydrophobicity and Zeta potential of the cell surface of the sludge were measured during the whole process. The variation of the extracellular polymer (EPS) in the process of granular growth and its correlation with the characteristics of the sludge were analyzed by three dimensional fluorescence spectrometry. The results are as follows: (1) the granulation time and the complete granulation time of aerobic sludge cultured in the reactor with coagulant PAC were 3 days and 12 days earlier than that of the reactor without coagulant respectively, and the intensity and specific gravity of aerobic sludge in the reactor were 2.05% higher than that in the control group, respectively. And 0.032, the shape rules of granular sludge formed under coagulation-enhanced granulation, (2) the hydrophobicity of granular sludge in reactor R1 was maintained at about 75% and Zeta potential was about -11 MV. The surface hydrophobicity and Zeta potential of sludge were higher than those of the reactor without PAC, but the changes of surface hydrophobicity and Zeta potential of sludge showed the same trend. And it can be seen that the rise rate of Zeta potential of R1 is faster than that of R2 without adding PAC. (3) Three-dimensional EPS fluorescence spectrum analysis of different forms of granular sludge under coagulation-enhanced granulation is found. The peak point of loose extracellular polymer (LB-EPS) in growing stage was soluble microbial metabolites, a small amount of aromatic protein and humic acids, and the fluorescence intensity of metabolites and proteins of dissolved microbes decreased after particle maturation. Humic acids disappear, However, the peak point and intensity of dissolved extracellular polymer (S-EPS) and compact extracellular polymer (TB-EPS) did not change significantly in the two stages. (4) the changes of EPS content during aerobic granular sludge formation showed that the contents of S-EPS and TB-EPS were not regular in the whole process. However, the content of LB-EPS increased with the increase of particle growth, and decreased to a stable level after maturation. The content of protein and LB-EPS in the main components were the same, while the content of polysaccharide was maintained at 1-5 mg/g MLSS. (5) LB-EPS, compared with that of S-EPS and TB-EPS. LB-EPS has a strong linear correlation with the SVI of aerobic granular sludge, and its correlation coefficient is: 1 / r ~ (0.812). The relative hydrophobicity and Zeta potential of aerobic sludge were also correlated with the content of PN in LB-EPS, and the correlation coefficients were: 1 r-0.996 and r-0.937, respectively.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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