铁自养反硝化污泥富集培养过程中化学与生物作用的变化规律

Deciphering the evolution of biological and chemical process in acclimatization of autotrophic iron-dependent denitrifying sludge

铁自养反硝化技术在低碳氮比废水处理中具有安全性高、成本低廉等优势,但目前对其反硝化过程机理,特别是其中生物与化学作用的关系仍缺乏清晰认识。为此,以铁自养反硝化系统为研究对象,结合反应动力学,分析不同阶段活性污泥自养反硝化过程中生物和化学作用变化规律,以期探究该过程的脱氮机制。结果表明,铁自养反硝化过程脱氮效率和速率分别可达(87.0±1.8)%和0.12 kg·(m^(3)·d)^(-1)。铁自养条件下,未经驯化的活性污泥在反硝化过程中,Fe(Ⅱ)氧化由化学作用主导,NO_(2)^(+)-N还原由生物作用主导,且生物过程由自养反硝化和以胞外聚合物为底物的异养反硝化共同作用;经驯化培养,Fe(Ⅱ)氧化的生物作用增强,与NO_(2)^(+)-N还原均由生物作用主导。以上研究结果可为铁自养反硝化脱氮技术的发展提供参考。

Iron-dependent autotrophic denitrification technology has advantages of high safety and low cost in treating wastewater with a low C/N ratio. However, till date, the denitrification mechanism of this technology,especially the relationship between biological and chemical process remains unclear. To unravel such a relationship and explore its denitrification mechanism, this work adopted reaction kinetics to investigate the evolution of biological and chemical reactions in the acclimation of an autotrophic iron-dependent denitrifying sludge at different stages. The results showed that the denitrification efficiency and rate of the autotrophic irondependent denitrifying sludge could reach(87.0±1.8)% and 0.12 kg·(m^(3)·d)^(-1), respectively. Under the irondependent autotrophic condition, the Fe(Ⅱ) oxidation was dominated by chemical reaction during the denitrification of the seeding activated sludge, while the NO_(2)^(+)-N reduction was dominated by biological reaction,and the biological process was co-acted by autotrophic denitrification and heterotrophic denitrification with extracellular polymer substances as substrates. For the acclimated sludge, the biological Fe(Ⅱ) oxidation was enhanced, and the NO_(2)^(+)-N reduction was dominated by biological reaction. This work can provide a theoretical basis for the development of iron-dependent autotrophic denitrification technology.