Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia.
Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia.
Environ Int. 2020 Apr;137:105501. doi: 10.1016/j.envint.2020.105501. Epub 2020 Feb 4.
An innovative process coupling anaerobic ammonium oxidation (anammox) with nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) in membrane biofilm reactors (MBfRs) has been developed to achieve high-level nitrogen removal from both sidestream (i.e., anaerobic digestion liquor) and mainstream (i.e., domestic strength) wastewater. In this study, a 1D biofilm model embedding the n-DAMO and anammox reactions was developed to facilitate further understanding of the process and its optimization. The model was calibrated and validated using comprehensive data sets from two independent MBfRs, treating sidestream- and mainstream-strength wastewater, respectively. Modelling results revealed a unique biofilm stratification. While anammox bacteria dominated throughout the biofilm, n-DAMO archaea (coupling nitrate reduction with anaerobic methane oxidation) only occurred at the inner layer and n-DAMO bacteria (coupling nitrite reduction with anaerobic methane oxidation) spread more evenly with a slightly higher fraction in the outer layer. The established MBfRs were robust against dynamic influent flowrates and nitrite/ammonium ratios. Thicker biofilms were beneficial for not only the total nitrogen (TN) removal but also the system robustness. Additionally, a positive correlation between the nitrogen removal efficiency and the residual methane emission was observed, as a result of higher methane partial pressure required. However, there was a threshold of methane partial pressure, above which the residual methane increased but nitrogen removal efficiency was stable. Meanwhile, thicker biofilms were also favorable to achieve less residual methane emission. Simulation results also suggested the feasibility of methane-based MBfRs to polish mainstream anammox effluent to meet a stringent N discharge standard (e.g., TN < 5 mg/L).
一种创新性的工艺将厌氧氨氧化（anammox）与亚硝酸盐/硝酸盐依赖型厌氧甲烷氧化（n-DAMO）耦合在膜生物膜反应器（MBfRs）中，以实现从侧流（即厌氧消化液）和主流（即生活污水）中高效去除氮。在这项研究中，嵌入 n-DAMO 和 anammox 反应的 1D 生物膜模型被开发出来，以促进对该过程及其优化的进一步理解。该模型使用来自分别处理侧流和主流废水的两个独立 MBfRs 的综合数据集进行了校准和验证。建模结果揭示了独特的生物膜分层。虽然 anammox 细菌在整个生物膜中占主导地位，但 n-DAMO 古菌（将硝酸盐还原与厌氧甲烷氧化偶联）仅发生在内层，n-DAMO 细菌（将亚硝酸盐还原与厌氧甲烷氧化偶联）则更均匀地分布，在外层的比例略高。所建立的 MBfRs 对动态进水流量和亚硝酸盐/氨氮比具有很强的鲁棒性。较厚的生物膜不仅有利于总氮（TN）去除，还有利于提高系统的鲁棒性。此外，由于需要更高的甲烷分压，观察到氮去除效率与残余甲烷排放之间存在正相关。然而，存在一个甲烷分压的阈值，超过该阈值，残余甲烷增加，但氮去除效率稳定。同时，较厚的生物膜也有利于实现较少的残余甲烷排放。模拟结果还表明，基于甲烷的 MBfRs 具有将主流 anammox 出水进一步处理以达到严格的 N 排放标准（例如，TN < 5 mg/L）的可行性。
