Compound microbial inocula were enriched and applied to a pilot-scale constructed wetland system to investigate their bioaugmentation effect on nitrogen removal under cold temperature (10 degrees C). The results showed a 10% higher removal efficiency of ammonia and total nitrogen compared to a control (unbioaugmented) group. The microbial community structures before and after the bioaugmentation were analyzed through high throughput sequencing using Miseq Illumina platform. A variation of species richness and community equitability was observed in both systems. It is demonstrated that, based on the response of both the performance and microbial community, bioaugmentation using compound microbial inocula can fine tune the bacterial population and enhance the nitrogen removal efficiency of a constructed wetland system. (C) 2016 Elsevier Ltd. All rights reserved.