Insights into the mechanism of the deterioration of mainstream partial nitritation/anammox under low residual ammonium  

作　　者：Yandong Yang Yiming Jiang Yanan Long Jiarui Xu Changqing Liu Liang Zhang Yongzhen Peng 

机构地区：[1]School of Environmental and Municipal Engineering,Qingdao University of Technology,Qingdao 266033,China [2]National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology,Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering,Beijing University of Technology,Beijing 100124,China

出　　处：《Journal of Environmental Sciences》2023年第4期29-39,共11页环境科学学报（英文版）

基　　金：financially supported by the Natural Science Foundation of Shandong Province, China (No. ZR2019BEE070);a Project of Shandong Province Higher Educational Science and Technology Program (No. J18KA207)。

摘　　要：Residual ammonium is a critical parameter affecting the stability of mainstream partial nitritation/anammox(PN/A), but the underlying mechanism remains unclear. In this study,mainstream PN/A was established and operated with progressively decreasing residual ammonium. PN/A deteriorated as the residual ammonium decreased to below 5 mg/L, and this was paralleled by a significant loss in anammox activity in situ and an increasing nitrite oxidation rate. Further analysis revealed that the low-ammonium condition directly decreased anammox activity in situ via two distinct mechanisms. First, anammox bacteria were located in the inner layer of the granular sludge, and thus were disadvantageous when competing for ammonium with ammonium-oxidizing bacteria(AOB) in the outer layer. Second, the complete ammonia oxidizer(comammox) was enriched at low residual ammonium concentrations because of its high ammonium affinity. Both AOB and comammox presented kinetic advantages over anammox bacteria. At high residual ammonium concentrations,nitrite-oxidizing bacteria(NOB) were effectively suppressed, even when their maximum activity was high due to competition for nitrite with anammox bacteria. At low residual ammonium concentrations, the decrease in anammox activity in situ led to an increase in nitrite availability for nitrite oxidation, facilitating the activation of NOB despite the dissolved oxygen limitation(0.15–0.35 mg/L) for NOB persisting throughout the operation. Therefore, the deterioration of mainstream PN/A at low residual ammonium was primarily triggered by a decline in anammox activity in situ. This study provides novel insights into the optimized design of mainstream PN/As in engineering applications.

关 键 词：Mainstream partial nitritation/anammox Residual ammonium Granular sludge Comammox 

分 类 号：X703[环境科学与工程—环境工程]