State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, P. R. China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, P. R. China.
Water Res. 2021 Jan 1;188:116498. doi: 10.1016/j.watres.2020.116498. Epub 2020 Oct 5.
Complete biological denitrification is usually restricted in electron donor lacking waters. Hydrogenotrophic denitrification attracts attention for its clean and cost-efficiency advantages. Therein, the hydrogen could be effectively generated by microbial electrolysis cells (MECs) from organic wastes. In this study, a gas diffusion membrane (GDM) integrated MEC (MMEC) was constructed and provided a novel non-polluting approach for nitrate contaminated water remediation, in which the hydrogen was recovered from substrate degradation in anode and diffused across GDM as electron donor for denitrification. The high overall nitrogen removal of 91 ± 0.1%-95 ± 1.9% and 90 ± 1.6%-94 ± 2.2% were respectively achieved in Ti-MMEC and SS-MMEC with titanium and stainless-steel mesh as cathode at all applied voltages (0.4-0.8 V). Decreasing applied voltage from 0.8 to 0.4 V significantly improved the electron utilization efficiency for denitrification from 26 ± 3.6% to 73 ± 0.1% in Ti-MMEC. Integrating MEC with GDM greatly improved TN removal by 40% under applied voltage of 0.8 V. The hydrogenotrophic denitrifiers of Rhodocyclaceae, Paracoccus, and Dethiobacter, dominated in MMECs facilitating TN removal. Functional denitrification related genes including napAB, nirKS, norBC and nosZ predicted by PICRUSt2 based on 16S rRNA gene data demonstrated higher abundance in MMECs.
完全的生物反硝化通常受到电子供体缺乏的限制。氢营养型反硝化因其清洁和经济高效的优势而受到关注。在这种情况下，微生物电解池（MEC）可以有效地从有机废物中产生氢气。本研究构建了一种气体扩散膜（GDM）集成 MEC（MMEC），为硝酸盐污染水的修复提供了一种新颖的无污染方法，其中氢气是从阳极基质降解中回收的，并通过 GDM 扩散作为反硝化的电子供体。在所有施加电压（0.4-0.8 V）下，钛和不锈钢网分别作为阴极的 Ti-MMEC 和 SS-MMEC 分别实现了 91±0.1%-95±1.9%和 90±1.6%-94±2.2%的高总氮去除率。将施加电压从 0.8 V 降低到 0.4 V 显著提高了 Ti-MMEC 中反硝化的电子利用效率，从 26±3.6%提高到 73±0.1%。将 MEC 与 GDM 集成，在施加电压为 0.8 V 时，可将 TN 去除率提高 40%。MMEC 中主要存在 Rhodocyclaceae、Paracoccus 和 Dethiobacter 等氢营养型脱氮菌，有利于 TN 的去除。基于 16S rRNA 基因数据，通过 PICRUSt2 预测的功能反硝化相关基因 napAB、nirKS、norBC 和 nosZ 在 MMEC 中丰度更高。
