Ikem Juliet, Chen Huiyu, Delatolla Robert
Department of Civil Engineering, Ottawa-Carleton Institute for Environmental Engineering, University of Ottawa, Ottawa, ON, Canada.
Front Microbiol. 2023 Mar 29;14:1142570. doi: 10.3389/fmicb.2023.1142570. eCollection 2023.
There is a current need for a low operational intensity, effective and small footprint system to achieve stable partial nitritation for subsequent anammox treatment at mainstream municipal wastewaters. This research identifies a unique design strategy using an elevated total ammonia nitrogen (TAN) surface area loading rate (SALR) of 5 g TAN/md to achieve cost-effective, stable, and elevated rates of partial nitritation in a moving bed biofilm reactor (MBBR) system under mainstream conditions. The elevated loaded partial nitritation MBBR system achieves a TAN surface area removal rate (SARR) of 2.01 ± 0.07 g TAN/md and NO -N: NH -N stoichiometric ratio of 1.15:1, which is appropriate for downstream anammox treatment. The elevated TAN SALR design strategy promotes nitrite-oxidizing bacteria (NOB) activity suppression rather than a reduction in NOB population as the reason for the suppression of nitrite oxidation in the mainstream elevated loaded partial nitritation MBBR system. NOB activity is limited at an elevated TAN SALR likely due to thick biofilm embedding the NOB population and competition for dissolved oxygen (DO) with ammonia-oxidizing bacteria for TAN oxidation to nitrite within the biofilm structure, which ultimately limits the uptake of DO by NOB in the system. Therefore, this design strategy offers a cost-effective and efficient alternative for mainstream partial nitritation MBBR systems at water resource recovery facilities.
目前需要一种运行强度低、有效且占地面积小的系统，以实现主流城市污水的稳定部分亚硝化，用于后续的厌氧氨氧化处理。本研究确定了一种独特的设计策略，即使用5 g TAN/md的升高的总氨氮（TAN）表面积负荷率（SALR），在主流条件下的移动床生物膜反应器（MBBR）系统中实现具有成本效益、稳定且升高的部分亚硝化速率。升高负荷的部分亚硝化MBBR系统实现了2.01±0.07 g TAN/md的TAN表面积去除率（SARR）和1.15:1的NO -N:NH -N化学计量比，这适用于下游的厌氧氨氧化处理。升高的TAN SALR设计策略促进了亚硝酸盐氧化细菌（NOB）活性的抑制，而不是NOB数量的减少，这是主流升高负荷的部分亚硝化MBBR系统中亚硝酸盐氧化受到抑制的原因。在升高的TAN SALR下，NOB活性受到限制，可能是由于厚厚的生物膜包裹了NOB群体，并在生物膜结构内与氨氧化细菌竞争溶解氧（DO）用于将TAN氧化为亚硝酸盐，这最终限制了系统中NOB对DO的摄取。因此，这种设计策略为水资源回收设施中的主流部分亚硝化MBBR系统提供了一种具有成本效益和高效的替代方案。
