Abstract Nowadays, nitrate represents one of the major contaminants of the hydrosphere, mainly affecting the quality of groundwater intended to the production of drinking water. This study proposes the use of Fe(II)-driven autotrophic denitrification as a high-potential, innovative bioprocess to couple microbially-catalyzed nitrate reduction to Fe(II) oxidation. Two identical up-flow packed bed reactors (PBRs), i.e. PBR1 and PBR2, with granular activated carbon as biofilm carrier were seeded with a Thiobacillus-mixed culture and operated for 153 days at different feed nitrate concentrations and hydraulic retention times (HRTs). The results show enhanced nitrate removal rates and efficiencies at increasing nitrate loading rates. In particular, nitrate removal and Fe(II) oxidation up to 85 and 95 %, respectively, were achieved in PBR1 at nitrate loading rates as high as 12.5 mg NO3−/L/h. Besides not undermining the denitrification efficiency, increasing the nitrate loading rate from 8.1 to 12.5 mg NO3−/L/h led to specific nitrate removal rates as high as 14.3 mg NO3−/g VS/h. In PBR2, Fe(II)-driven denitrification was investigated at a constant nitrate loading rate by concomitantly decreasing the feed nitrate concentration and HRT. Despite the less severe operational conditions, the use of lower nitrate loading rates resulted in a lower nitrate removal efficiency than that obtained in PBR1.

中文翻译：

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Fe(II)驱动自养反硝化在不同硝酸盐负载率下填充床反应器中的评价

摘要 如今，硝酸盐是水圈的主要污染物之一，主要影响用于生产饮用水的地下水的质量。本研究建议使用 Fe(II) 驱动的自养反硝化作为一种​​高潜力、创新的生物过程，将微生物催化的硝酸盐还原与 Fe(II) 氧化结合起来。两个相同的上流式填充床反应器 (PBR)，即 PBR1 和 PBR2，以颗粒活性炭作为生物膜载体，接种硫杆菌混合培养物，并在不同的进料硝酸盐浓度和水力停留时间 (HRT) 下运行 153 天。结果表明，随着硝酸盐负载率的增加，硝酸盐去除率和效率提高。特别是，硝酸盐去除率和 Fe(II) 氧化率分别高达 85% 和 95%，在 PBR1 中以高达 12.5 mg NO3-/L/h 的硝酸盐负载率实现。除了不破坏反硝化效率外，将硝酸盐负载率从 8.1 增加到 12.5 毫克 NO3-/L/h 导致特定硝酸盐去除率高达 14.3 毫克 NO3-/g VS/h。在 PBR2 中，通过同时降低进料硝酸盐浓度和 HRT，在恒定硝酸盐负载率下研究了 Fe(II) 驱动的反硝化。尽管操作条件不太苛刻，但使用较低的硝酸盐负载率导致硝酸盐去除效率低于 PBR1 中获得的效率。通过同时降低进料硝酸盐浓度和 HRT，在恒定硝酸盐负载率下研究了 Fe(II) 驱动的反硝化作用。尽管操作条件不太苛刻，但使用较低的硝酸盐负载率导致硝酸盐去除效率低于 PBR1 中获得的效率。通过同时降低进料硝酸盐浓度和 HRT，在恒定硝酸盐负载率下研究了 Fe(II) 驱动的反硝化作用。尽管操作条件不太苛刻，但使用较低的硝酸盐负载率导致硝酸盐去除效率低于 PBR1 中获得的效率。