铁矿物强化厌氧氨氧化效能及其微生物机制研究进展

自然界中的氮循环与铁循环相互交联，参与氮循环的厌氧氨氧化（anaerobic ammonium oxidation，anammox）菌的生长代谢及活性发挥也与铁元素紧密关联。自然界广泛存在的铁矿物因具有运行成本低廉、稳定性好、二次污染小等优势，在污水处理领域得到广泛应用。在厌氧氨氧化脱氮系统中引入适量铁矿物，不仅有助于促进anammox菌和铁还原菌的富集，提高功能基因丰度和相关酶活性，还可能通过影响污泥浓度、血红素c含量、胞外聚合物含量和颗粒化程度，改善污泥性能和提高厌氧氨氧化系统的稳定性。同时，铁矿物具有促进体系多种氮素转化途径（如anammox、铁自养反硝化、铁氨氧化、异化硝酸盐还原成铵和反硝化）相耦合的潜能，可以提高anammox污水处理系统的总氮去除率。本文基于铁矿物在促进污水生物脱氮方面的良好性能及其在anammox系统中的变化，从脱氮效能、污泥特性、微生物特征及酶活性等方面，系统综述了铁矿物对厌氧氨氧化系统的强化作用机制，并从anammox菌对铁矿物的利用及铁元素的摄取角度展望了后续的研究方向，以期为铁矿物强化厌氧氨氧化系统的实际应用提供理论和技术指导。

Efficiency and microbial mechanism of iron minerals in enhancing the anammox: a review

As the nitrogen cycle is cross-linked with the iron cycle in the nature, the metabolism and activity of anaerobic ammonia oxidation (anammox) bacteria involved in the nitrogen cycle are also closely related to the iron element. Being ubiquitous in the nature, iron minerals have been widely used for wastewater treatment, owing to the advantages of low operating cost, good stability, and low secondary pollution. The addition of a moderate amount of iron minerals not only can promote the enrichment of anammox bacteria and iron-reducing bacteria in the anammox system, and increase the abundance of functional genes and the activities of related enzymes, but also can regulate the sludge concentration, heme c content, extracellular polymeric substance (EPS) content, and granulation degree to improve the sludge properties and the anammox system stability. Meanwhile, iron minerals have the potential to promote the coupling of multiple nitrogen transformation pathways, such as the anammox, nitrate-dependent Fe(II) oxidation (NDFO), ferric ammonium oxidation (Feammox), dissimilatory nitrate reduction to ammonia (DNRA), and denitrification, which can improve the total nitrogen removal efficiency for the anammox system. Focusing on the good performance of iron minerals in promoting biological denitrification of wastewater and their varieties in the anammox system, the mechanism of iron minerals in enhancing the anammox system is systematically summarized in this study from nitrogen removal efficiency, sludge properties, microbial community characteristics, and enzymes activities. Moreover, the future research directions are prospected from the perspectives of the utilization of iron minerals and the uptake of the iron element by anammox bacteria, aiming to provide theoretical and technical guidance for the application of iron minerals in the anammox system.