Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Environ Res. 2023 Dec 1;238(Pt 2):117241. doi: 10.1016/j.envres.2023.117241. Epub 2023 Sep 29.
Zero-valent iron based autotrophic denitrification (ZVI-AD) has attracted increasing attentions in nitrate removal due to saving organic carbon budget in wastewater treatment, but limited by the low reaction speed, poor electron transfer efficiency as well as the compaction/blocking by iron hydrolysis products. Humic substances (HS) were promising to regulate iron cycle and accelerate electron transfer by serving as electron mediators. In this study, HS analogue, antraquinone-2, 6-disulfonate (AQDS), was added to enhance ZVI-AD process. Results showed that the dosage of AQDS led to a NO-N removal efficiency of 83.37 ± 3.98% within 96 h, which was 32.28 ± 1.25% higher than that in ZVI-AD system. The corrosion of ZVI and microbially nitrate reduction were both improved at the presence of AQDS. The addition of AQDS enriched the functional species, including autotrophic denitrobacteria namely Thauera and Hydrogenophaga, iron redox-related species namely Ferruginibacter and HS respiration related species namely Flavobacterium. The genes napA and napB related to electron transfer, nirK and nosZ related to the accumulation of intermediate products were also enriched by the addition of AQDS. AQDS addition boosted the electrons flowing to both abiotic and biotic nitrate reduction. Nitrate removal mechanism involved in ZVI-AQDS coupled system was proposed. This study provided an alternative strategy for improving ZVI-AD by HS.
零价铁自养反硝化（ZVI-AD）由于在污水处理中节省有机碳预算而在硝酸盐去除中受到越来越多的关注，但受到反应速度低、电子传递效率差以及铁水解产物的压实/堵塞的限制。腐殖质（HS）有望通过充当电子介体来调节铁循环并加速电子传递。在这项研究中，添加了腐殖质类似物蒽醌-2,6-二磺酸钠（AQDS）来增强 ZVI-AD 工艺。结果表明，AQDS 的剂量导致在 96 小时内 NO-N 的去除效率达到 83.37±3.98%，比 ZVI-AD 系统高 32.28±1.25%。AQDS 的存在改善了 ZVI 的腐蚀和微生物硝酸盐还原。AQDS 的添加丰富了功能物种，包括自养脱氮菌如 Thauera 和 Hydrogenophaga、铁氧化还原相关物种如 Ferruginibacter 和 HS 呼吸相关物种如 Flavobacterium。添加 AQDS 还富集了与电子转移相关的基因 napA 和 napB、与中间产物积累相关的基因 nirK 和 nosZ。AQDS 促进了电子流向非生物和生物硝酸盐还原。提出了 ZVI-AQDS 耦合系统的硝酸盐去除机制。本研究为 HS 改善 ZVI-AD 提供了一种替代策略。
