Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Water Sci Technol. 2013;68(3):650-7. doi: 10.2166/wst.2013.288.
Changes in ammonia-oxidizing bacterial (AOB) population dynamics were examined in a new sponge-based trickling filter (TF) post-upflow anaerobic sludge blanket (UASB) reactor by denaturating gradient gel electrophoresis (DGGE), and these changes were linked to relevant components influencing nitrification (chemical oxygen demand (COD), nitrogen (N)). The sponge-based packing media caused strong concentration gradients along the TF, providing an ecological selection of AOB within the system. The organic loading rate (OLR) affected the population dynamics, and under higher OLR or low ammonium-nitrogen (NH4(+)-N) concentrations some AOB bands disappeared, but maintaining the overall community function for NH4(+)-N removal. The dominant bands present in the upper portions of the TF were closely related to Nitrosomonas europaea and distantly affiliated to Nitrosomonas eutropha, and thus were adapted to higher NH4(+)-N and organic matter concentrations. In the lower portions of the TF, the dominant bands were related to Nitrosomonas oligotropha, commonly found in environments with low levels of NH4(+)-N. From a technology point of view, changes in AOB structure at OLR around 0.40-0.60 kgCOD m(-3) d(-1) did not affect TF performance for NH4(+)-N removal, but AOB diversity may have been correlated with the noticeable stability of the sponge-based TF for NH4(+)-N removal at low OLR. This study is relevant because molecular biology was used to observe important features of a bioreactor, considering realistic operational conditions applied to UASB/sponge-based TF systems.
采用变性梯度凝胶电泳（DGGE）技术研究了新型海绵生物滴滤塔（TF）后置上流厌氧污泥床（UASB）反应器中氨氧化细菌（AOB）种群动态的变化，并将这些变化与影响硝化作用（化学需氧量（COD）、氮（N））的相关因素联系起来。海绵载体的填充介质在 TF 内形成了强烈的浓度梯度，为系统内 AOB 的生态选择提供了条件。有机负荷率（OLR）影响种群动态，在较高 OLR 或较低铵氮（NH4(+)-N）浓度下，一些 AOB 条带消失，但保持了 NH4(+)-N 去除的整体群落功能。TF 上部存在的优势条带与欧洲亚硝化单胞菌（Nitrosomonas europaea）密切相关，与亚硝化螺菌（Nitrosomonas eutropha）关系较远，因此适应于较高的 NH4(+)-N 和有机物浓度。在 TF 的下部，优势条带与寡养硝化单胞菌（Nitrosomonas oligotropha）有关，寡养硝化单胞菌通常存在于 NH4(+)-N 水平较低的环境中。从技术角度来看，在 OLR 为 0.40-0.60 kgCOD m(-3) d(-1)左右时，AOB 结构的变化不会影响 TF 对 NH4(+)-N 的去除性能，但 AOB 的多样性可能与海绵 TF 在低 OLR 下对 NH4(+)-N 去除的显著稳定性有关。本研究具有重要意义，因为分子生物学用于观察生物反应器的重要特征，考虑到实际操作条件应用于 UASB/海绵 TF 系统。
