Characteristics of Nutrients Removal under Viscous Sludge Bulking Treating Synthetic Wastewater

Viscous sludge bulking is a rare phenomenon in activated sludge process.The performances of nutrients removal were investigated with normal sludge and viscous bulking sludge.The results showed that when COD loading and C/N ratio were around 0.13 mg COD/(mg MLSS·d)and 7.67,the effect of viscous sludge bulking on the maximum specific oxidation rates of NH_(4)^(+)⁃N was very little,while the maximum specific oxidation rates of NO_(2)^(-)⁃N decreased from 24.69 mg/(g·h)to 1.20 mg/(g·h).Compared with normal sludge,viscous bulking sludge had bigger particle size and more extracellular polymeric substances(EPS).The mass transfer resistance in sludge flocs might be the main cause of the difference in NO-2⁃N oxidation rates.Therefore,this study demonstrates that viscous sludge bulking is beneficial to enhance simultaneous nitrification and denitrification(SND),and excessive EPS will exhibit storage function during phosphorus removal process.

Microlunatus phosphovorus与Tetrasphaera的葡萄糖代谢特征及其在生物除磷过程中的协同与竞争机制研究

本研究旨在探究强化生物除磷(Enhanced Biological Phosphorus Removal,EBPR)工艺中两种常见的聚磷菌(Polyphosphate Accumulating Organisms,PAOs):Microlunatus phosphovorus(积磷小月菌)和Tetrasphaera以葡萄糖为碳源条件下的代谢特征与竞争机制.通过厌氧-好氧全周期实验,系统表征了两种PAOs的摄碳除磷动力学参数以及碳源利用与除磷的计量学关系.结果表明,在厌氧阶段,Microlunatus phosphovorus平均以109.2 mg·g^(-1)·h^(-1)的速率摄取葡萄糖(厌氧碳源摄取/释磷计量比为0.82),将葡萄糖以糖原的形式储存在细胞内,此过程中未检测到发酵产物的生成;在好氧阶段,Microlunatus phosphovorus利用在厌氧条件下储存的糖原供能吸收磷酸盐,其吸磷速率为22.6 mg·g^(-1)·h^(-1).相较之下,在厌氧阶段,Tetrasphaera的葡萄糖摄取速率明显较低(6.10 mg·g^(-1)·h^(-1),厌氧碳源摄取/释磷计量比为0.64),其将葡萄糖发酵成乙酸、琥珀酸和乳酸并排出胞外;好氧段则继续摄取葡萄糖,为吸收磷酸盐提供能量,其吸磷速率为3.7 mg·g^(-1)·h^(-1).此外,探究了Microlunatus phosphovorus和Tetrasphaera以葡萄糖为碳源条件下的相互作用特征.两者以1∶1的比例共存时,实际厌氧阶段净释磷量小于理论释磷量而葡萄糖的摄取量则大于理论值,表明两者存在碳源摄取过程中的相互促进作用.好氧阶段,两者共存可实现更低的出水磷酸盐浓度.本文通过利用葡萄糖作为唯一碳源对纯菌培养的Microlunatus phosphovorus和Tetrasphaera进行代谢研究及摄碳除磷动力学研究,构建了Microlunatus phosphovorus和Tetrasphaera以葡萄糖为碳源时的代谢模型,探究了两者的相互作用关系,研究结果将为提高以葡萄糖作为碳源条件下强化生物除磷系统运行稳定性与除磷效率提供理论支撑.