School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, China.
Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
Water Res. 2021 Feb 15;190:116716. doi: 10.1016/j.watres.2020.116716. Epub 2020 Dec 1.
Sulfur-oxidizing bacteria (SOB) can drive a high level of autotrophic denitrification (AD) activity with thiosulfate (SO) as the electron donor. However, the slow growth of SOB results in a low biomass concentration in the AD reactor and unsatisfactory biological nitrogen removal (BNR). In this study, our goal was to establish a high-rate thiosulfate-driven denitrification (TDD) system via sludge granulation. Granular sludge was successfully cultivated by increasing the nitrogen loading rate stepwise in thiosulfate-oxidizing/nitrate-reducing conditions in an upflow anaerobic blanket reactor. In the mature-granular-sludge reactor, a nitrate removal rate of 280 mg N/L/h was achieved with a nitrate removal efficiency of 97.7%±1.0% at a hydraulic retention time of only 15 minutes, with no nitrite detected in the effluent. Extracellular polymeric substance (EPS) analysis indicated that the proteins in loosely bound and tightly bound EPS were responsible for maintaining the compact structure of the TDD granular sludge. The dynamics of the microbial-community shift were identified by 16S rRNA high-throughput pyrosequencing analysis. The Sulfurimonas genus was found to be enriched at 74.1% of total community and may play the most critical role in the high-rate BNR. The batch assay results reveal that no nitrite accumulation occurred during nitrate reduction because the nitrate reduction rate (75.90±0.67 mg N/g MLVSS/h) was almost equal to the nitrite reduction rate (66.06±1.28 mg N/g MLVSS/h) in the thiosulfate-driven granular sludge reactor. The results of this study provide support for the establishment of a high-rate BNR system that maintains its stability with a low sludge yield.
硫氧化菌 (SOB) 可以利用硫代硫酸盐 (SO) 作为电子供体驱动高水平的自养反硝化 (AD) 活性。然而，SOB 的缓慢生长导致 AD 反应器中的生物量浓度较低，生物氮去除 (BNR) 效果不理想。在本研究中，我们的目标是通过污泥颗粒化建立一个高速率的硫代硫酸盐驱动的反硝化 (TDD) 系统。通过在硫氧化/硝酸盐还原条件下逐步增加氮负荷，在上流式厌氧生物膜反应器中成功培养出颗粒污泥。在成熟的颗粒污泥反应器中，在水力停留时间仅为 15 分钟的情况下，硝酸盐去除率达到 280mg N/L/h，硝酸盐去除效率为 97.7%±1.0%，且出水无亚硝酸盐检出。胞外聚合物 (EPS) 分析表明，松散结合和紧密结合 EPS 中的蛋白质负责维持 TDD 颗粒污泥的紧凑结构。通过 16S rRNA 高通量焦磷酸测序分析确定了微生物群落变化的动态。发现 Sulfurimonas 属在总群落中富集了 74.1%，可能在高 BNR 中发挥最重要的作用。批处理试验结果表明，由于硝酸盐还原速率 (75.90±0.67mg N/g MLVSS/h) 几乎等于硫代硫酸盐驱动颗粒污泥反应器中亚硝酸盐还原速率 (66.06±1.28mg N/g MLVSS/h)，因此硝酸盐还原过程中没有亚硝酸盐积累。本研究结果为建立一个低污泥产率且保持稳定性的高 BNR 系统提供了支持。
