Enhancing nitrogen removal of real industrial nitrogen-containing wastewater by a simultaneous partial denitrification-anammox process with exogenous glycine betaine adding

Advanced nitrogen removal from real industrial nitrogen -containing wastewater was investigated in the simultaneous partial denitrification-anammox (PD-anammox) process with glycine betaine (GB) addition. Two parallel reactors (R1 as the control and R2 supplemented with 0.1 mmol/L GB additionally) were continuously operated with different COD/NO3 -N (C/N) ratios of 3.0, 2.5, and 2.0, respectively. It was indicated that adding 0.1 mmol/ L GB significantly enhanced the partial denitrification and anammox reaction rates by 23.97 % and 41.90 %, as well as decreasing carbon source requirement by 16.67 %. Moreover, the nitrogen removal efficiency in R2 reached 89.35 %, higher than that of R1 (74.65 %). The higher protein/polysaccharide (6.73-8.50) in R2 played a critical role in promoting microbial stability in the treatment of real industrial wastewater. Microbial community analysis showed that Ca. Brocadia sp. was the primary anammox genus, while OLB8 (18.06 %) in R2 and Thauera (17.67 %) in R1 were the dominant denitrification genera. In general, exogenous GB can reduce the requirement for carbon source, improve the microbial activity of AnAOB and HDB, thereby enhancing the nitrogen removal performance of the PD-anammox system in treating actual industrial wastewater. This work provides an economical and environment -friendly solution for the effective treatment of actual industrial ammonium nitrate -containing wastewater.