Abstract:

Ferroammonium oxidation (anaerobic ammonium oxidation coupled to Fe (Ⅲ) reduction, Feammox) refers to a new type of sewage biological denitrification process under the condition of anaerobic, ammonia-nitrogen oxidation coupled with ferric iron reduction. To explore nitrogen conversion pathways and their contribution to nitrogen removal in Feammox, the activated sludge was used as seed sludge to acclimate. After 120 d of operation, the maximum conversion efficiency of \mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N} reached 53.8% and the maximum conversion amount was 26.9 mg/L, in which Feammox accounted for about 57.7% and Anammox about 42.3%. In typical cycle operation, nitrogen conversion was 14.74 mg/L within 0—7 h, in which Anammox dominated. During 7—24 h the nitrogen conversion was 12.16 mg/L, mainly by Feammox. The nitrate removal through NDFO during the whole operation was about 5 mg/L. Based on the correlation analysis, \mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N} concentration was significantly positively related to Fe(Ⅲ) and \mathrm{N}{\mathrm{O}}_{\mathrm{2}}^{-}-\mathrm{N} (P_Fe<0.05,P_{\mathrm{N}{\mathrm{O}}_{\mathrm{2}}}<0.01), while \mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}-\mathrm{N} was negatively related to Fe(Ⅲ) (P < 0.5). Synergy of Feammox, Anammox and NDFO achieved the autotrophic nitrogen removal from wastewater.

Key words: activated sludge, anaerobic, Feammox, Anammox, NDFO, correlation analysis, autotrophic nitrogen removal, molecular biology

摘要：

铁氨氧化（anaerobic ammonium oxidation coupled to Fe(Ⅲ) reduction，Feammox）是指在厌氧条件下，氨氮氧化耦合三价铁还原的一种新型污水生物脱氮工艺。为确定Feammox反应系统中存在的氮转化的途径，在厌氧条件下接种普通活性污泥驯化培养Feammox，探究了不同途径对氨氮转化的贡献率并进行了相关性分析。研究结果表明：在厌氧间歇反应器ASBR中，经过120 d的富集培养，\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N}最大去除率达53.8%，最大去除量约26.9 mg/L，其中Feammox反应途径对\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N}去除的贡献率为57.7%，厌氧氨氧化(Anammox)约占42.3%。在典型周期分析发现，在0~7 h内对\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N}去除量为14.74 mg/L，Anammox反应速率较快，起主导作用；7~24 h 对\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N}去除量为12.16 mg/L，以Feammox反应为主；在整个运行周期内铁盐反硝化（nitrate-dependent Fe(Ⅱ) oxidizing，NDFO）去除\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}-\mathrm{N}约5 mg/L。由相关性分析可得，\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-\mathrm{N}浓度与Fe(Ⅲ)、\mathrm{N}{\mathrm{O}}_{\mathrm{2}}^{-}-\mathrm{N}浓度呈显著性正相关（P_Fe<0.05、P_{\mathrm{N}{\mathrm{O}}_{\mathrm{2}}}<0.01），而\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}-\mathrm{N}与Fe(Ⅲ)呈负相关（P<0.5）。实验结果表明在Feammox、Anammox以及NDFO共同作用下，该系统实现了污水自养型脱氮。

关键词: 活性污泥, 厌氧, Feammox, Anammox, NDFO, 相关性分析, 自养型脱氮, 分子生物学