Abstract The effect of the sludge retention time (SRT) on the stability and performance of an aerobic granular sludge (AGS) sequencing-batch reactor (SBR) on the simultaneous organic matter, nitrogen and phosphorus removal from simulated domestic wastewater was assessed in a long-term study (392 days). Operated under alternating anaerobic-aerobic conditions, the reactor was subjected to four experimental conditions: uncontrolled SRT (run I), SRT of 30 (run II), 20 (run III) and 15 days (run IV). The results showed that COD removal was kept stable and over 90 % throughout the SBR operation, regardless of the SRT. On the other hand, by allowing the sludge age to be dependent on natural solids washout by effluent withdrawal (SRT of 47–61 days), phosphate removal was substantially low (15 %), as also observed at an SRT of 30 days. Filamentous bacteria overgrowth was noticed at the later conditions, which affected the stability of the granular biomass, leading to a deterioration of its settling properties. The ratio between the sludge volume index after 30 and 5 min of settling (SVI30/SVI5) was around 0.70. Biological phosphate removal started to thrive at the sludge age of 20 days (35 %), reaching around 100 % at SRT of 15 days, at which the highest P-release/COD uptake ratio (0.14 mg P/mgCOD) and specific phosphate uptake (11.4 mgPO43−-P/(gVSS h)) were observed. Under the lowest SRT applied, the granules exhibited better structural and settling properties, with the SVI30/SVI5 ratio reaching almost 1.0. Moreover, nitrification was kept stable, and, even though nitrite build-up occurred during the SBR cycle, nitrate was the main oxidized nitrogen form in the effluent. Average COD, ammonium and total nitrogen removal amounted to 93 %, 97 % and 58 %. Cycle tests under normal and special conditions were carried out to assess specific nitrification, denitrification and phosphate uptake rates, and elucidate the key players in the biological conversions processes taking place in the AGS reactor. No phosphate uptake coupled to nitrate reduction was noticed, implying that P removal was not driven by denitrifying dephosphatation activity. To track the dynamics of important microbial functional groups, fluorescence in situ hybridization analysis was conducted.

中文翻译：

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污泥龄对好氧颗粒污泥的影响：解决养分去除性能和生物质稳定性

摘要 污泥滞留时间 (SRT) 对好氧颗粒污泥 (AGS) 序批式反应器 (SBR) 稳定性和性能的影响对模拟生活废水中同时去除有机物、氮和磷的影响进行了长期评估。 - 学期学习（392 天）。在交替的厌氧-好氧条件下运行，反应器经受四种实验条件：不受控制的 SRT（运​​行 I）、SRT 为 30（运行 II）、20（运行 III）和 15 天（运行 IV）。结果表明，在整个 SBR 操作过程中，COD 去除率保持稳定且超过 90%，而与 SRT 无关。另一方面，通过允许污泥龄依赖于排出废水（SRT 为 47-61 天）的自然固体冲刷，磷酸盐去除率非常低（15%），这在 SRT 为 30 天时也观察到。在后期条件下观察到丝状细菌过度生长，这影响了颗粒生物质的稳定性，导致其沉降性能变差。沉降 30 和 5 分钟后的污泥体积指数之间的比值 (SVI30/SVI5) 约为 0.70。生物除磷在 20 天的污泥龄 (35 %) 开始蓬勃发展，在 15 天的 SRT 时达到 100 % 左右，此时磷释放/COD 吸收比 (0.14 毫克 P/mgCOD) 和特定磷酸盐吸收率最高(11.4 mgPO43--P/(gVSS h))被观察到。在最低 SRT 应用下，颗粒表现出更好的结构和沉降性能，SVI30/SVI5 比值几乎达到 1.0。此外，硝化作用保持稳定，即使在 SBR 循环期间发生亚硝酸盐累积，硝酸盐仍是流出物中主要的氧化氮形式。平均 COD、铵和总氮去除率分别为 93%、97% 和 58%。在正常和特殊条件下进行循环测试以评估特定的硝化、反硝化和磷酸盐吸收率，并阐明 AGS 反应器中生物转化过程的关键参与者。没有注意到与硝酸盐减少相关的磷酸盐吸收，这意味着除磷不是由反硝化脱磷活性驱动的。为了跟踪重要微生物功能组的动态，进行了荧光原位杂交分析。并阐明在 AGS 反应器中发生的生物转化过程中的关键参与者。没有注意到与硝酸盐减少相关的磷酸盐吸收，这意味着除磷不是由反硝化脱磷活性驱动的。为了跟踪重要微生物功能组的动态，进行了荧光原位杂交分析。并阐明在 AGS 反应器中发生的生物转化过程中的关键参与者。没有注意到与硝酸盐减少相关的磷酸盐吸收，这意味着除磷不是由反硝化脱磷活性驱动的。为了跟踪重要微生物功能组的动态，进行了荧光原位杂交分析。