Department of Civil and Environmental Engineering, Western University, London, Canada.
Suez Water Technologies and Solutions, Oakville, Canada.
Environ Technol. 2023 Nov;44(26):4084-4097. doi: 10.1080/09593330.2022.2079998. Epub 2022 Jun 6.
Carbon redirection has become the desired option for sustainable and energy-efficient wastewater treatment due to its contribution to a circular economy. However, its impact on downstream processes such as nitrification and denitrification requires further investigation. This research characterizes the nitrogen removal performance, footprint, aeration mode, and microbial composition of a flow-through membrane aerated biofilm reactor (MABR) downstream of a chemically enhanced primary treatment (CEPT) carbon redirection unit. The batch and long-term studies demonstrated relatively higher nitrification rates than those reported using conventional primary treated wastewaters. The results indicated that reducing carbon in the liquid train positively impacted nitrification by achieving 87 ± 12% (1.4 ± 0.4 g/m.d) ammonia removal with an effluent 2.5 ± 2.8 mg/L ammonia concentration at a short hydraulic retention time (HRT) of 2.5 h. Despite the lower (1.9 ± 1) soluble COD:N, up to 75 ± 25% (0.6 ± 0.4 g/m.d) total nitrogen removal was achieved at 4 h HRT by implementing intermittent aeration. The batch tests using the developed biofilms showed nitrification (denitrification) capacity up to 11 ± 1.7 gNH-N/m.d (8.5 ± 0.5 gNO-N/m.d) and 2.7 ± 0.6 gNH-N/m.d (2 ± 0.3 gNO-N/m.d) corresponding to ammonia and nitrate concentrations ranging from 10-30 mg/L and 2-10 mg/L, respectively. Microbial analysis indicated that the nitrifiers such as Nitrosomonas and Nitrospira were the dominant species. The ammonia-oxidizing, nitrite-oxidizing, and denitrifying bacteria relative abundances were 10.3 ± 1.5%, 20.7 ± 1.7%, and 20.0 ± 2.8% under continuous aeration and 1.3 ± 0.07%, 1.8 ± 0.09%, and 40.5 ± 3.1% under intermittent aeration, supporting the observed ammonia and total nitrogen removal processes, respectively. Overall, the results demonstrated that MABR downstream of the CEPT behave differently; thus, design guides should be updated accordingly.
由于其对循环经济的贡献，碳转向已成为可持续和节能废水处理的理想选择。然而，其对硝化和反硝化等下游工艺的影响需要进一步研究。本研究描述了经过化学增强的一级处理（CEPT）碳转向单元后的流动膜曝气生物膜反应器（MABR）的氮去除性能、足迹、曝气方式和微生物组成。批量和长期研究表明，硝化速率相对较高，高于使用传统一级处理废水的报道。结果表明，通过在短水力停留时间（HRT）为 2.5 小时时实现 87±12%（1.4±0.4 g/m.d）的氨去除率和 2.5±2.8 mg/L 的出水氨浓度，使液体列车中的碳减少，对硝化产生积极影响。尽管可溶 COD:N 较低（1.9±1），但通过实施间歇曝气，在 4 h HRT 下可实现高达 75±25%（0.6±0.4 g/m.d）的总氮去除。使用开发的生物膜进行的批量测试表明，硝化（反硝化）能力高达 11±1.7 gNH-N/m.d（8.5±0.5 gNO-N/m.d）和 2.7±0.6 gNH-N/m.d（2±0.3 gNO-N/m.d），对应于氨和硝酸盐浓度分别为 10-30 mg/L 和 2-10 mg/L。微生物分析表明，硝化菌如亚硝化单胞菌和硝化螺旋菌是优势物种。在连续曝气下，氨氧化菌、亚硝酸盐氧化菌和反硝化菌的相对丰度分别为 10.3±1.5%、20.7±1.7%和 20.0±2.8%，在间歇曝气下分别为 1.3±0.07%、1.8±0.09%和 40.5±3.1%，分别支持观察到的氨和总氮去除过程。总的来说，结果表明 CEPT 下游的 MABR 表现不同；因此，设计指南应相应更新。
