Changes Of Microbial Community Structure And Their Influencing Factors During Shortcut Biological Nitrogen Removal In River

When the exogenous nitrogen is under control, the release of endogenous nitrogen is the main cause of water pollution in river. Intermittent aeration is an efficient technology of biological denitrification. In this study, the shortcut biological nitrogen removal was realized by intermittent aeration in overlying water. During intermittent aeration, the characteristics of microbial community structure were studied with molecular biology methods, and the main environmental factors affecting microorganisms were investigated by redundancy analysis. The analysis of the microbial community structure in overlying water indicated that the Cornarnonas played an important role in the shortcut nitrification stage, and that shortcut denitrifying bacteria were not found in the shortcut denitrification stage. Redundancy analysis suggested that dissolved oxygen, pH and free ammonia had obvious effects on microorganisms in the shortcut nitrification stage, and that dissolved oxygen, pH, free ammonia and ammonia nitrogen had great influence on microorganisms in the shortcut denitrification stage. The analysis of the microbial community structure in sediment showed that shortcut nitrification bacteria were not found during the shortcut nitrification stage, and that the Thauera is an impotant denitrification bacteria in the shortcut denitrification stage. Redundancy analysis suggested that dissolved oxygen and pH had significant effects on microorganisms in the shortcut nitrification stage, and that pH and nitrite nitrogen had great effects on microorganisms in shortcut denitrification stage. This study may throw some light on the further study of microorganisms during the treatment of polluted river,