Abstract: Carbon fiber as a biofilm carrier has denitrification ability yet with long biofilm formation period and inferior initial water purification capacity. To improve the film-forming and denitrification performance of carbon fiber, nitrogen-removing bacteria was adopted to strengthen the film-forming effect of carbon fiber. The strengthening effect of nitrogen removal agent on carbon fiber supported microbial membrane was explored, and the denitrification performance of carbon fiber undergone film-forming was also examined. Results unveiled that the film-forming performance of carbon fiber could be significantly enhanced by nitrogen-removing bacteria. The microbial biomass and carbon source metabolic activity of microorganisms of carbon fibers in the enhanced membrane group were significantly higher than those in the natural membrane group, with the peak value of microbial biomass of the enhanced membrane group 10.3 times that in the natural membrane group, and carbon source metabolic activity of microorganisms 3.5 times that in the natural membrane group. Moreover, the nitrogen removal efficiency of strengthened carbon fiber was significantly improved, with the reduction rates of total nitrogen and ammonia nitrogen of strengthened membrane carbon fiber group increasing by 8.0% and 14.1%, respectively, compared with the natural membrane carbon fiber group. The research findings offer scientific basis and technical support for applying artificially strengthened carbon fiber to eutrophication treatment.

Key words: carbon fiber, nitrogen-removing bacteria, film-forming, denitrification, microbial biomass