School of Environmental and Chemical Engineering, Shanghai Electric Power University, Shanghai 201306, China; College of Environmental Science and Engineering, Institute of Carbon Neutrality, State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.
College of Environmental Science and Engineering, Institute of Carbon Neutrality, State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.
Sci Total Environ. 2023 Jun 15;877:162784. doi: 10.1016/j.scitotenv.2023.162784. Epub 2023 Mar 10.
The present study investigated the potential of diatomite addition in enhancing sludge settlement of two-stage PN/Anammox for real reject water treatment, with a focus on sludge settling velocity, nitrogen removal capacity, sludge morphological features, and microbial community changes. The study found that diatomite addition significantly improved the sludge settleability of the two-stage PN/A process, resulting in a decrease in sludge volume index (SVI) from 70 to 80 mL/g to about 20-30 mL/g for both PN and Anammox sludge, although the sludge-diatomite interaction differed between the two types of sludge. In the PN sludge, diatomite acted as a carrier, while in the Anammox sludge, it acted as micro-nuclei. The addition of diatomite also increased the biomass amounts in the PN reactor, with a 5-29 % improvement attributed to its role as a biofilm carrier. The effects of diatomite addition on sludge settleability were more prominent at high mixed liquor suspended solids (MLSS), where sludge characteristics were deteriorated. Furthermore, the settling rate of the experimental group consistently exceeded that of the blank group after diatomite addition, with a significant decrease in SV. The relative abundance of Anammox bacteria was improved, and sludge particle size decreased in the diatomite-added Anammox reactor. Diatomite was effectively retained in both reactors, with less loss observed for Anammox than PN due to its more tightly wrapped structure, resulting in a stronger sludge-diatomite interaction. Overall, the results of this study suggest that diatomite addition has potential in enhancing the settling properties and performance of two-stage PN/Anammox for real reject water treatment.
本研究探讨了在处理实际 reject 水时添加硅藻土来增强两级 PN/Anammox 中污泥沉降性能的潜力，重点关注污泥沉降速度、氮去除能力、污泥形态特征和微生物群落变化。研究发现，添加硅藻土可显著改善两级 PN/A 工艺的污泥沉降性能，使 PN 和 Anammox 污泥的污泥体积指数（SVI）从 70-80 mL/g 降低到约 20-30 mL/g，尽管两种污泥中硅藻土与污泥的相互作用有所不同。在 PN 污泥中，硅藻土充当载体，而在 Anammox 污泥中，它充当微核。添加硅藻土还增加了 PN 反应器中的生物量，生物量提高了 5-29%，这归因于其作为生物膜载体的作用。硅藻土添加对污泥沉降性能的影响在高混合液悬浮固体（MLSS）下更为明显，此时污泥特性恶化。此外，添加硅藻土后实验组的沉降速率始终高于空白组，SV 显著降低。Anammox 细菌的相对丰度提高，添加硅藻土的 Anammox 反应器中污泥粒径减小。硅藻土在两个反应器中均得到有效保留，由于其更紧密的包裹结构，Anammox 的损失比 PN 少，导致污泥-硅藻土相互作用更强。总体而言，本研究结果表明，添加硅藻土可能会增强两级 PN/Anammox 处理实际 reject 水的沉降性能和性能。
