State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, P. R. China; School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, 710129, 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. 2022 Jul 15;220:118675. doi: 10.1016/j.watres.2022.118675. Epub 2022 May 25.
Elemental sulfur (S)-based autotrophic denitrification (SAD) has gained intensive attention in the treatment of secondary effluent for its low cost, high efficiency, and good stability. However, in practice, the supplementary addition of limestone is necessary to balance the alkalinity consumption during SAD operation, which increases water hardness and reduces the effective reaction volume. In this study, a coupled sulfur and electrode-driven autotrophic denitrification (SEAD) process was proposed with superior nitrate removal performance, less accumulation of sulfate, and self-balance of acidity-alkalinity capacity by regulating the applied voltage. The dual-channel electron supply from S and electrodes made the nitrate removal rate constant k in the SEAD process 3.7-5.1 and 1.4-3.5 times higher than that of the single electrode- and sulfur-driven systems, respectively. The S° contributed to 75.3%-83.1% of nitrate removal and the sulfate yield during SEAD (5.67-6.26 mg SO/mg NO-N) was decreased by 17%-25% compared with SAD. The S particle and electrode both as active bio-carriers constructed collaborative denitrification communities and functional genes. Pseudomonas, Ralstonia and Brevundimonas were the dominant denitrifying genera in S particle biofilm, while Pseudomonas, Chryseobacterium, Pantoea and Comamonas became dominant denitrifying genera in the cathode biofilm. The narG/Z/H/Y/I/V, nxrA/B, napA/B, nirS/K, norB/C and nosZ were potential functional genes for efficient nitrate reduction during the SEAD process. Metagenomic sequencing indicated that S as an electron donor has greater potential for complete denitrification than the electrode. These findings revealed the potential of SEAD for acting as a highly efficient post denitrification process.
基于元素硫（S）的自养反硝化（SAD）因其低成本、高效率和良好的稳定性而在处理二级出水方面受到了广泛关注。然而，在实际应用中，有必要补充添加石灰石来平衡 SAD 运行过程中的碱度消耗，这会增加水的硬度并降低有效反应体积。本研究提出了一种耦合硫和电极驱动的自养反硝化（SEAD）工艺，通过调节施加的电压，具有卓越的硝酸盐去除性能、较少的硫酸盐积累和自我平衡的酸碱性能力。S 和电极的双通道电子供应使 SEAD 工艺中的硝酸盐去除速率常数 k 分别比单电极和硫驱动系统高 3.7-5.1 倍和 1.4-3.5 倍。SEAD 过程中 S°贡献了 75.3%-83.1%的硝酸盐去除量，硫酸盐生成量（5.67-6.26 mg SO/mg NO-N）比 SAD 减少了 17%-25%。S 颗粒和电极均作为活性生物载体构建了协同反硝化群落和功能基因。假单胞菌、罗尔斯通氏菌和 Brevundimonas 是 S 颗粒生物膜中主要的反硝化属，而 Pseudomonas、Chryseobacterium、Pantoea 和 Comamonas 成为阴极生物膜中主要的反硝化属。narG/Z/H/Y/I/V、nxrA/B、napA/B、nirS/K、norB/C 和 nosZ 是 SEAD 过程中高效硝酸盐还原的潜在功能基因。宏基因组测序表明，S 作为电子供体比电极具有更大的完全反硝化潜力。这些发现揭示了 SEAD 作为一种高效后置反硝化工艺的潜力。
