A novel system of CW–BER was developed for nitrogen removal of low C/N wastewater.
The nitrate and ammonia nitrogen could be removed in the coupled system.
Heterotrophic and autotrophic denitrifier had effects on nitrogen removal.
Highest removal efficiency of nitrate and TN was 63.03% and 98.11%, respectively.
Enhancive removal of nitrate and TN of CW–BER was 23.26% and 24.20%, respectively.