School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, PR China.
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore; College of Geography and Environment, Collaborative Innovation Center of Human-Nature and Green Development in Universities of Shandong, Shandong Normal University, Jinan 250014, PR China.
Sci Total Environ. 2020 Apr 1;711:135087. doi: 10.1016/j.scitotenv.2019.135087. Epub 2019 Nov 21.
Oxygen has not been purposely introduced to the autotrophic denitrification systems and simultaneous nitrification/autotrophic denitrification (SNAD) has not been proposed. In this study, oxygen was introduced into a micro-electrolysis-enhanced Fe-supported autotrophic denitrification (mFeAD) system. The nitrogen removal performance was investigated and the application potential of iron-scraps-supported simultaneous nitrification/mFeAD was evaluated. The results showed that FeAD was surprisingly enhanced by oxygen together with nitrification at average dissolved oxygen (DO) of 0.08-1.56 mg/L. The ammonia oxidizing bacterial, nitrite oxidizing bacteria, facultative autotrophic denitrificans, and iron compounds transformation bacteria were markedly enriched. Average denitrification rate shifted from 0.116 to 0.340 kg N/(m·d) with increase of average total nitrogen removal efficiency from 31.4% to 90.5%. Oxygen could enhance the biological conversion and storage of iron compounds, which was capable of reducing the coating of Fe surface.The accelerating of oxygen on Fe0 passivation appeared when increasing the average DO from 1.56 to 2.17 mg/L. Therefore, the SNAD was recommended to be operated at the DO range of 0.08-1.56 mg/L. ME significantly enhanced FeAD, and the utilization of iron-scraps reduced its cost. The denitrification rate is comparable with methanol supported heterotrophic denitrification with 58.9% reduction on the cost. The iron-scraps supported SNAD is competitive in both denitrification rate and costs in the ammonia contaminated low-carbon water treatment.
氧气并未特意引入自养反硝化系统，也未提出同时硝化/自养反硝化（SNAD）。在本研究中，将氧气引入微电解增强铁支持的自养反硝化（mFeAD）系统。考察了氮去除性能，并评估了铁屑支持的同时硝化/mFeAD 的应用潜力。结果表明，在平均溶解氧（DO）为 0.08-1.56mg/L 时，氧气与硝化作用一起出人意料地增强了 FeAD。氨氧化细菌、亚硝酸盐氧化细菌、兼性自养反硝化菌和铁化合物转化菌明显富集。平均反硝化速率从 0.116kgN/（m·d）增加到 0.340kgN/（m·d），平均总氮去除效率从 31.4%增加到 90.5%。氧气可以增强铁化合物的生物转化和储存，减少 Fe 表面的涂层。当平均 DO 从 1.56mg/L 增加到 2.17mg/L 时，氧气加速了 Fe0 的钝化。因此，建议在 0.08-1.56mg/L 的 DO 范围内进行 SNAD。微电解显著增强了 FeAD，铁屑的利用降低了其成本。与甲醇支持的异养反硝化相比，脱氮率降低了 58.9%，成本降低。在氨污染低碳水处理中，铁屑支持的 SNAD 在脱氮速率和成本方面均具有竞争力。
