中文摘要：

以序批式反应器培养的好氧颗粒污泥为对象，从出水MLSS、COD、污泥粒径分布、污泥圆形度及复杂度角度，研究颗粒污泥失稳过程及其成因。结果表明，出水MLSS从接种时的693．3mg／L降低至稳定运行至67d时的9．5mg／L，出水COD保持在50mg／L以下，去除率由89．3％增加至98．1％。随着颗粒污泥的失稳，出水MLSS由9．5mg／L增加至507．6mg／L，出水COD增加至在70mg／L，去除率为94．2％，好氧颗粒污泥逐渐转变为真菌颗粒。颗粒粒径急剧增大，圆形度降低，复杂度增加，说明失稳后的真菌形状不规则，沉降性能因此变差。这是由于在有机冲击负荷条件下，部分有机物未能充分降解而酸化，导致pH值提高，丝状真菌在与细菌的竞争中有优势，导致菌群失稳，功能菌群被淘汰，最终导致颗粒失稳。

英文摘要：

On the basis of concentrations of effluent mixed liquid suspended solids （MLSS）, effluent chemical oxygen demand （cOD）, granule size distribution, roundness and complexity, mechanism of the instability process of aerobic granular sludge cultivated in the sequencing batch reactor （SBR） was investigated. Experimental results showed that when the reactor reached steady state, the effluent MLSS in SBR decreased from 693.3 mg/L to 9.5 mg/L at 67 d, the effluent COD kept below 50 mg/L, and removal efficiency of COD increased from 89.3% to 98.1%. After 67 th day, the effluent MLSS increased again to 507.6 rag/L, the effluent COD increased to 70 mg/L, and removal efficiency of COD decreased to 94.2%. Aerobic granular sludge gradually changed to fungal granules and the granule size increased. Granule roundness and complexity increased, indicating the shape of fungal granules was irregular, and this was due to acidification of partial organics which were degraded insufficiently when organic shock loads existed. The filamentous fungi won the competition to bacterium at low pH.