Effects of key enzyme activities and microbial communities in a flocculent-granular hybrid complete autotrophic nitrogen removal over nitrite reactor under mainstream conditions.
Recently, a flocculent-granular hybrid reactor was reported as a novel nitrogen removal system; however, the mechanisms of stable operation in the system remain unclear. In this study, the mechanisms of the stable nitrogen removal performance in a flocculent-granular hybrid system were investigated with temperature reduction. The operational period was divided into three phases with different temperatures ranges. In phase I, the nitrogen removal efficiency was stabilized at about 90% with nitrogen removal load maintained at approximately 0.28 kg N/(m3·day). In phase II, while decreasing the temperature to 20 °C, the activities of key enzymes were reduced immediately and were then maintained at a certain level. The relative abundances of aerobic ammonium-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria gradually increased at this phase. In phase III, after the temperature dropped to 15 °C, the activities of key enzymes gradually increased due to adaptation to low temperature, boosting the nitrogen removal efficiency to 83%.
['Li|Bolin|B|', 'Yan|Wenkai|W|', 'Wang|Yue|Y|', 'Wang|Heng|H|', 'Zhou|Zhi|Z|', 'Li|Ye|Y|', 'Zhang|Wenqin|W|']
D064751:Ammonium Compounds D052818:Autotrophic Processes D001421:Bacteria, Anaerobic D019149:Bioreactors D058440:Denitrification D005427:Flocculation D064307:Microbiota D009573:Nitrites D009584:Nitrogen D010084:Oxidation-Reduction D012722:Sewage D013696:Temperature
Key enzyme activities Mainstream Hybrid reactor Anammox Microbial community structure