VFAs对好氧/延长静置系统除磷微生物的影响

在2个序批式反应器中,研究了废水中常见的两种挥发性脂肪酸乙酸、丙酸对于AEI强化生物除磷的影响。结果表明,短期的驯化中,R1的除磷效果优于R2,两者去除率为75.5%和61.8%。随着驯化的进行,R2的除磷效果提升。48～96 d,R1和R2的去除率为76.95%和92.1%。两者除磷效率的高低与微生物体内聚磷水平密切相关。静置期,R1和R2有明显释磷现象。     

Metabolic shift of polyphosphate-accumulating organisms with different levels of polyphosphate storage

Previous studies have shown that polyphosphate-accumulating organisms (PAOs) are able to behave as glycogen-accumulating organisms (GAOs) under different conditions. In this study we investigated the behavior of a culture enriched with Accumulibacter at different levels of polyphosphate (poly-P) storage. The results of stoichiometric ratios Gly_degraded/HAc_uptake, PHB_synthesized/HAc_uptake, PHV_synthesized/HAc_uptake and P_release/HAc_uptake confirmed a metabolic shift from PAO metabolism to GAO metabolism: PAOs with high poly-P content used the poly-P to obtain adenosine tri-phosphate (ATP), and glycogen (Gly) to obtain nicotinamide adenine dinucleotide (NADH) and some ATP. In a test where poly-P depletion was imposed on the culture, all the acetate (HAc) added in each cycle was transformed into polyhydroxyalkanoate (PHA) despite the decrease of poly-P inside the cells. This led to an increase of the Gly_degraded/HAc_uptake ratio that resulted from a shift towards the glycolytic pathway in order to compensate for the lack of ATP formed from poly-P hydrolysis. The shift from PAO to GAO metabolism was also reflected in the change in the PHA composition as the poly-P availability decreased, suggesting that polyhydroxyvalerate (PHV) is obtained due to the consumption of excess reducing equivalents to balance the internal NADH, similarly to GAO metabolism. Fluorescence in situ hybridization analysis showed a significant PAO population change from Type I to Type II Accumulibacter as the poly-P availability decreased in short term experiments. This work suggests that poly-P storage levels and GAO-like metabolism are important factors affecting the competition between different PAO Types in enhanced biological phosphorus removal systems.     

自养硝化污泥除磷能力研究

采用静态试验对自养硝化污泥的除磷特性进行研究.分别提供氨、无机碳源和氨、无机碳源三种营养条件,考察了厌氧-好氧交替环境下硝化细菌摄取磷酸盐的情况.结果表明:在与聚磷菌的运行模式相对应的条件下,硝化污泥无除磷效果;通过染色观察,硝化细菌体内几乎没有PHB颗粒及异染颗粒;按照传统聚磷菌除磷模式培养的硝化细菌未表现出明显的除磷特性.论文从能量利用、营养类型及培养条件等方面对该现象和产生的原因进行了分析.