Denitrifying bioelectrochemical systems (BES) allow safe nitrate treatment in waters with low organic carbon content without chemical requirements and at a competitive cost. However, this technology should move towards scaling-up by improving removal rate capabilities. In this study, a novel tubular design was used to evaluate whether the hydraulic retention time and the influent nitrate concentration influence the nitrate removal rate of denitrifying BES. A nitrate consumption rate of up to 849 g N m_NCC⁻³ d⁻¹ was reached without accumulation of nitrites at a HRT of 28 minutes. Nitrate removal activity was evaluated under different nitrate influent concentrations and under different HRTs. Results suggested preeminence of HRT on modulating the denitrifying activity. Therefore, this study presents an innovative design for nitrate removal using denitrifying BES and it demonstrates that operation at low HRTs increases the nitrate removal rate. It suggests that an appropriate approximation of scaling-up denitrifying BES would be the implementation of compact reactors connected in series operated at low HRTs.

中文翻译：

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水力停留时间和反硝化生物电化学系统中底物可用性的影响

反硝化生物电化学系统（BES）可在有机化学含量低的水中安全地进行硝酸盐处理，而无需化学要求，且价格具有竞争力。但是，该技术应通过提高清除率功能而逐步扩大规模。在这项研究中，一种新颖的管状设计用于评估水力停留时间和进水硝酸盐浓度是否影响反硝化BES的硝酸盐去除率。硝酸盐消耗速率高达849 g N m _NCC ^-3 d ^-1在28分钟的HRT达到亚硝酸盐累积而无亚硝酸盐。在不同的硝酸盐进水浓度和不同的HRT下，评估了硝酸盐去除活性。结果表明，HRT在调节反硝化活性方面具有优势。因此，本研究提出了一种使用反硝化BES去除硝酸盐的创新设计，并证明了在低HRT下运行可提高硝酸盐去除率。这表明按比例放大反硝化BES的适当近似方法是在低HRT时串联运行的紧凑型反应堆。