State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China.
State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China.
Environ Res. 2022 Apr 1;205:112564. doi: 10.1016/j.envres.2021.112564. Epub 2021 Dec 11.
In this study, for the first time, endogenous denitrification (ED) was enhanced in a practical anaerobic-anoxic-oxic-[post-anoxic]-[post-oxic] (AAO-AO) process, contributing to a remarkable increase in the nitrogen removal efficiency (NRE). The long-term operation (203 days) result showed that the NRE was improved by 7% compared to the theoretical maximum NRE (68-70%) of AAO processes, with the effluent total nitrogen (TN) decreasing from 13.7 (1 d) to 6.1 mg/L (203 d). Approximately 99.4% of the influent COD was transformed to poly-β-hydroxyalkanoates (PHAs) in the anaerobic zone. The synthesized PHAs were consumed in the following zones and the secondary sedimentation tank accompanied by over 32.5% N-loss, indicating that the ED process could be responsible for the enhanced NRE. 16S rRNA amplicon sequencing results further confirmed that denitrifying glycogen-accumulating organisms, which are capable of ED, were enriched with the relative abundance of 2.10%. Our findings provide a novel cost- and energy-efficient strategy to improve nitrogen removal without external carbon additions but by enhancing ED performance.
在这项研究中，首次在实际的厌氧-缺氧-好氧-（缺氧后）-（好氧后）（AAO-AO）工艺中增强了内源性反硝化（ED），从而显著提高了氮去除效率（NRE）。长期运行（203 天）的结果表明，与 AAO 工艺的理论最大 NRE（68-70%）相比，NRE 提高了 7%，出水总氮（TN）从 13.7（1d）降至 6.1mg/L（203d）。大约 99.4%的进水 COD 在厌氧区转化为聚-β-羟基烷酸酯（PHAs）。合成的 PHAs 在以下区域和二次沉淀池被消耗，伴随着超过 32.5%的氮损失，表明 ED 过程可能是增强 NRE 的原因。16S rRNA 扩增子测序结果进一步证实，能够进行 ED 的反硝化糖原积累菌的相对丰度增加到 2.10%。我们的发现提供了一种新颖的、具有成本效益和节能的策略，可在不添加外部碳源的情况下提高氮去除率，同时增强 ED 性能。
