Quantitative Analysis of the Composition and Abundance ofNitrifying Bacteria on Simultaneous Nitrification and Denitrification in SBBR

Sequencing biofilm batch reactor (SBBR) was used to achieve simultaneous nitrification and denitrification (SND) in current study. With SBBR, microorganisms are immobilized on fillers as biofilm, which results in high biomass hold up and enables the process to be operated at high liquid throughputs and organic loading rates [1]. Compared with sludge-based systems, SBBR is generally less energy intensive and more resistant to shock loads to which wastewater treatment systems are frequently subjected [2]. Besides, SBBR is particularly useful where high hydraulic loading variations occur and where slowly growing microbes with special metabolic capacities can be protected from washout[3]. However, several studies approved that simultaneous nitrification and denitrification (SND) can complete biological nitrification coupled to denitrification in one structure [4-6]. At first, ammonia is oxidized to nitrite by ammonia-oxidizing bacteria (AOB) and, subsequently, nitrite is oxidized to nitrate by nitrite-oxidizing bacteria (NOB) [7]. Finally, denitrification involves the reduction of nitrate via nitrite and nitric oxide, to nitrous oxide or dinitrogen gas [8].