Park H-D, Regan J M, Noguera D R
Department of Civil & Environmental Engineering, University of Wisconsin, Madison 53706, USA.
Water Sci Technol. 2002;46(1-2):273-80.
Aerated-anoxic processes operate under the principle that small additions of oxygen to an anoxic reactor induce simultaneous nitrification and denitrification. In these systems, ammonia oxidation in the anoxic zone can easily account for 30-50% of the total nitrification in the reactor, even though the dissolve oxygen concentration is usually below detection limit. To investigate whether the nitrification efficiency in aerated-anoxic processes was due to the presence of specialized ammonia-oxidizing bacteria (AOB), an analysis of the AOB population in an aerated-anoxic Orbal process and a conventional nitrogen removal process was carried out using phylogenetic analyses based on the ammonia monooxygenase A (amoA) gene. Terminal restriction fragment length polymorphism (TRFLP) analyses revealed that Nitrosospira-like organisms were one of the major contributors to ammonia oxidation in a full-scale aerated-anoxic Orbal reactor. However, the relative populations of Nitrosospira-like and Nitrosomonas-like AOB were not constant and appeared to have seasonal variability. Cloning and sequence comparison of amoA gene fragments demonstrated that most of the AOB in the aerated-anoxic Orbal process belonged to the Nitrosospira sp. and Nitrosomonas oligotropha lineages. The abundance of Nitrosospira-like organisms in aerated-anoxic reactors is significant, since this group of AOB has not been usually associated with nitrification in wastewater treatment plants.
曝气-缺氧工艺基于向缺氧反应器中少量添加氧气可诱导同步硝化和反硝化的原理运行。在这些系统中，即使溶解氧浓度通常低于检测限，缺氧区的氨氧化也很容易占反应器总硝化作用的30%-50%。为了研究曝气-缺氧工艺中的硝化效率是否归因于专门的氨氧化细菌（AOB）的存在，基于氨单加氧酶A（amoA）基因，利用系统发育分析对曝气-缺氧奥贝尔工艺和传统脱氮工艺中的AOB种群进行了分析。末端限制性片段长度多态性（TRFLP）分析表明，类亚硝化螺菌属生物是全尺寸曝气-缺氧奥贝尔反应器中氨氧化的主要贡献者之一。然而，类亚硝化螺菌属和类亚硝化单胞菌属AOB的相对数量并不恒定，且似乎具有季节性变化。amoA基因片段的克隆和序列比较表明，曝气-缺氧奥贝尔工艺中的大多数AOB属于亚硝化螺菌属和寡营养亚硝化单胞菌谱系。曝气-缺氧反应器中类亚硝化螺菌属生物的丰度很高，因为这一类AOB通常与污水处理厂的硝化作用无关。
