Nitrogen removal from livestock and poultry breeding wastewaters using a novel sequencing batch biofilm reactor

A study was conducted regarding the biological nitrogen removal from the livestock and poultry breeding wastewater (LPBWs) using a novel sequencing batch biofilm reactor (SBBR). Nitrogen removal process was studied under three aeration strategies/modes, referred to as MODE 1, 2, and 3. The results showed that MODE 2 (one operation period: instant fill of LPBWs, 3.0 h aeration, 1.5 h non-aeration, 1.5 h aeration, 1.0 h non-aeration and rapid drain of treated LPBWs) performed the best in nitrogen removal. Under MODE 2, the removal efficiencies were as high as 96.1 and 92.1% for NH₃-N and TN, respectively. Simultaneous nitrification and denitrification (SND), as well as shortcut nitrification and denitrification are likely to be the two main mechanisms for the nitrogen removal in this study. Nitrifying bacteria were not inhibited by heterotrophic bacteria with C/N ratios ranging from 18.1 to 21.4 and DO concentration of 2.0 mg/l. Alternation between aeration and non-aeration played an important role in NO₂⁻ accumulation.