Northeastern University, Boston, Massachusetts.
University of Asia Pacific, Dhaka, Bangladesh.
Water Environ Res. 2020 Mar;92(3):389-402. doi: 10.1002/wer.1185. Epub 2019 Oct 14.
Investigations of the impact of solid residence time (SRT) on microbial ecology and performance of enhanced biological phosphorus removal (EBPR) process in full-scale systems have been scarce due to the challenges in isolating and examining the SRT from other complex plant-specific factors. This study performed a comprehensive evaluation of the influence of SRT on polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) dynamics and on P removal performance at Clark County Water Reclamation District Facility in Las Vegas, USA. Five parallel treatment trains with separated clarifiers were operated with five different SRTs ranging from 6 to 40 days. Microbial community analysis using multiple molecular and Raman techniques suggested that the relative abundances and diversity of PAOs and GAOs in EBPR systems are highly affected by the SRT. The resultant EBPR system stability and performance can be potentially controlled and optimized by manipulating the system SRT, and shorter SRT (<10 days) seems to be preferred. PRACTITIONER POINTS: Phosphorus removal performance and kinetics are highly affected by the operational solid residence time (SRT), with lower and more stable effluent P level achieved at SRT < 10 days. Excessive long SRTs above that needed for nitrification may harm EBPR performance; additionally, excessive long SRT may favor GAOs to dominate over PAOs and thus further reducing efficient use of rbCOD for EBPR. Microbial population abundance and diversity, especially those functionally relevant PAOs and GAOs, can impact the P removal performances, and they are highly dependent on the operational solid residence time. EBPR performance can be potentially controlled and optimized by manipulating the system SRT, and shorter SRT (≤10 days) seems to be preferred at the influent rbCOD/P ratio and environmental conditions as in the plant studied.
由于从其他复杂的工厂特定因素中分离和检查固体停留时间（SRT）存在挑战，因此对全规模系统中固体停留时间对微生物生态学和增强生物除磷（EBPR）性能的影响进行调查的研究很少。本研究对固体停留时间对聚磷菌（PAOs）和糖原积累菌（GAOs）动态以及对美国拉斯维加斯克拉克县水回收区设施的磷去除性能的影响进行了全面评估。五个平行的处理列车分别装有五个不同的 SRT（从 6 天到 40 天）。使用多种分子和拉曼技术进行微生物群落分析表明，EBPR 系统中 PAOs 和 GAOs 的相对丰度和多样性受 SRT 的高度影响。通过操纵系统 SRT，可以潜在地控制和优化由此产生的 EBPR 系统稳定性和性能，并且似乎更喜欢较短的 SRT（<10 天）。
磷去除性能和动力学受操作固体停留时间（SRT）的高度影响，在 SRT<10 天的情况下，可实现更低且更稳定的出水 P 水平。过长的 SRT（超过硝化所需的 SRT）可能会损害 EBPR 的性能；此外，过长的 SRT 可能有利于 GAOs 占主导地位而不是 PAOs，从而进一步降低 rbCOD 对 EBPR 的有效利用。微生物种群丰度和多样性，特别是那些与功能相关的 PAOs 和 GAOs，会影响磷去除性能，并且它们高度依赖于操作固体停留时间。通过操纵系统 SRT，可以潜在地控制和优化 EBPR 性能，并且在研究工厂中的进水 rbCOD/P 比和环境条件下，较短的 SRT（≤10 天）似乎更受欢迎。
