| 污泥龄对膜生物反应器性能的影响 |
| 摘要点击 1274 全文点击 1130 投稿时间：2007-09-29 修订日期：2007-12-03 |
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| 中文关键词 膜生物反应器 污泥龄 粒径分布 胞外聚合物 污泥特性 过滤阻力 |
| 英文关键词 membrane bioreactor (MBR) sludge retention time (SRT) size distribution extracellular polymeric substances (EPS) sludge characteristics filtration resistance |
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| 中文摘要 |
| 研究了膜生物反应器污泥龄对胞外聚合物（EPS）含量、污泥特性、污泥颗粒粒径分布及膜过滤阻力的影响.结果表明，污泥龄(SRT)为30 d时混合液中胞外聚合物(EPS)和膜面上的EPS含量分别约为90 mg/g、 0.8 g/m2，随污泥龄的延长二者同步增加，EPS在膜面上几乎没有积累；混合液EPS含量的增加改变了细菌表面电荷且增大了细菌表面亲水基和疏水基的比例，使细菌存在状态由不稳定型（R型）向稳定型（S型）转变，造成污泥的沉降困难；在长污泥龄运行中，混合液中污泥颗粒呈现双峰分布，泥龄30 d时在0.5 μm和16 μm处有2个峰且平均粒径约14 μm，污泥龄延长双峰分布向颗粒小的方向移动；混合液中微细颗粒含量及粒径分布对膜污染起决定性作用.综合考虑膜污染和污泥特性，膜生物反应器的污泥龄应控制在优势菌最小世代时间（运行温度下的最大比增长速度）的120倍以下. |
| 英文摘要 |
| The effects of sludge retention time (SRT) on extracellular polymeric substances (EPS) content, the characteristics of sludge，the size distribution of sludge particles and the membrane resistance of filtration in the membrane bioreactor were studied. The results indicate that the EPS content is about 90 mg/g in the mixed liquor and 0.8 g/m2 on the membrane surface at 30 d of SRT. And EPS contents increase simultaneously with the extension of SRT, but EPS is hardly accumulated on the membrane surface. In addition, the electric charge on the surface of bacteria change and the proportion of hydrophilic group and hydrophobic group enhance with the rise of the EPS content，then the bacteria are transformed from the unstable (R) from to the stable (S) and the sludge is difficult to settle. The size-distribution profile of particles in the mixed liquor presents a bimodal shape at the long SRT and the peak values shift to the smaller range with SRT extension，at 30 d of SRT the average size of particles is about 14 μm and the two peaks occur at 0.5 μm and 16 μm, respectively. It shows that the content and the size distribution of small particles in the mixed liquor are crucial to the membrane fouling. It is found that it is suitable to control the SRT of membrane bioreactor below 120 times of the shortest generation-time of dominant bacteria (at the highest specific growth rate under the operation temperature) considering the membrane pollution and the characteristics of the mixed liquor. |
