Research Centre of Environmental Microbial Resource Development and Application Engineering, Research Institute of Tsinghua University in Shenzhen, Guangdong 518000, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
Shenzhen Qingyan Environment Technology Co., Ltd., Guangdong 518000, China.
Sci Total Environ. 2020 Apr 20;714:136764. doi: 10.1016/j.scitotenv.2020.136764. Epub 2020 Jan 17.
This study investigated the aerobic sludge granulation and nitrogen removal performance in a modified airlift loop reactor treating municipal wastewater under different operation conditions. Dynamic feeding and aeration control were applied to create feast/famine conditions to facilitate microbial aggregation. Experimental results demonstrated that aerobic granular sludge could be cultivated in continuous-flow reactors fed with an optimized dynamic feeding condition. Fresh granules sizing 0.4-0.6 mm were observed in the reactors after a 61-day operation, then turned to matured granules after another 33-day operation with a compact structure, a stable size of 2-4 mm, and a low SVI of ~35 mL/g. Extracellular polymeric substances (EPS) analysis results showed that both EPS contents and the ratio of protein to polysaccharides increased with the granulation process, leading to an increase of cell hydrophobicity. Granular sludge exhibited a good nitrogen removal ability with a comparable level of specific nitrification rate and denitrification rate with those measured in state-of-the-art sequential batch reactors. Microbial population analysis showed an increase in the relative abundance of functional microbes, including Zoogloea, Nitrospira, Dechloromonas, and Thauera in the cultivated granules, suggesting a potentially crucial role of these microbes in sludge granulation and nitrogen removal. The dynamic feeding strategy and the reactor configuration are considered as critical factors for aerobic granulation under continuous-flow conditions for creating feast/famine conditions and allow sludge backflow without structure damage.
本研究考察了在不同运行条件下，改良气升式环流反应器处理城市污水时的好氧污泥颗粒化和脱氮性能。采用动态进料和曝气控制来创造丰/贫食条件，以促进微生物聚集。实验结果表明，在优化的动态进料条件下，可在连续流反应器中培养出好氧颗粒污泥。在 61 天的运行后，反应器中观察到粒径为 0.4-0.6mm 的新鲜颗粒，经过 33 天的运行后，颗粒成熟，结构紧凑，粒径稳定在 2-4mm，SVI 低至约 35mL/g。胞外聚合物（EPS）分析结果表明，随着颗粒化过程的进行，EPS 含量和蛋白质与多糖的比例均增加，导致细胞疏水性增加。颗粒污泥具有良好的脱氮能力，其比硝化速率和反硝化速率与先进的序批式反应器相当。微生物种群分析表明，在培养的颗粒中，功能微生物（如动胶菌属、硝化螺旋菌属、脱氯菌属和陶厄氏菌属）的相对丰度增加，表明这些微生物在污泥颗粒化和脱氮过程中可能发挥着重要作用。动态进料策略和反应器构型被认为是在连续流条件下实现好氧颗粒化的关键因素，可创造丰/贫食条件，并允许污泥回流而不会造成结构破坏。
