剪切应力对好氧颗粒污泥形态结构和微生物活性的影响机制研究

对不同剪切应力(0.189、0.267、0.327和0.377 N/m2)下4个序批式反应器(SBR)中好氧颗粒污泥的形态结构、比耗氧速率(SOUR)以及胞外聚合物进行了对比分析.结果表明,好氧颗粒污泥具有稳定的基本形态特征,其微生物主要由杆菌、球菌和丝状菌组成;其中杆菌能承受高剪切作用.是剪切应力为0.377 N/m2时的优势菌群.4个反应器中污泥粒径分布范围分别为0.2-0.5、0.5-1.5、0.5-1.5和0.3-0.5 mm;SOUR分别为34.54、40.08、46.26和46.42 mg/(g·h),胞外多聚糖分别为59.71、66-81、80.88和109.99 mg/g,胞外蛋白质分别为9.29、9.80、12.35和17.02 mg/g.好氧颗粒污泥比耗氧速率SOUR和胞外聚合物与剪切应力有很好的正相关性.确定了好氧颗粒污泥微生物活性与剪切应力的响应关系.

Effect of Shear Stress on Morphology, Structure and Microbial Activity of Aerobic Granules

The aerobic granules were cultivated in four sequencing batch reactors (SBRs) under the shear stress of 0.189, 0.267, 0.327 and 0.377 N/m2, respectively. The morphology and structure, specific oxygen utilization rate (SOUR) and extracellular polymeric substances of different aerobic granules were studied. Results show that aerobic granules can maintain the stable morphologic characteristics. A close examination of the granule surface revealed the presence of a large diversity of microbial morphotypes, including bacterial rods and cocci, and fungi. These microorganisms are embedded in an extracellular polymeric matrix. The bacterial robs were the dominant microbes in the granules under 0.377 N/m2. In the four reactors, the diameters of the granules are 0.2-0.5, 0.5-1.5, 0.5-1.5 and 0.3-0.5 mm; SOUR are 34.54, 40.08, 46.26 and 46.42 mg/(g x h); the extracellular polysaccharides are 59.71, 66.81, 80.88 and 109.99 mg/g; the extracellular proteins are 9.29, 9.80, 12.35 and 17.02 mg/g; respectively and correspondingly. The positive relationship of the microbial activity of the aerobic granules with the shear stress was introduced depending on the analysis of the variation of SOUR and extracellular polymeric substances.