Bioaugmentation of a biological contact oxidation ditch with indigenous nitrifying bacteria for in situ remediation of nitrogen-rich stream water

In this study, specialized bacteria were domesticated and cultivated with polluted stream water. The bioaugmentation of specialized bacteria would significantly enhance the removal efficiency of TN and NH4+–N from 25.9% to 50.3%, and from 34.5% to 60.1%, respectively. Concomitant increases in the number of microbial communities and the proportion of nitrifying bacteria were also identified by the most probable number (MPN) method. PCR–DGGE profiles revealed that the bacterial community could be successfully enriched and the ammonia-oxidizing bacteria communities were shown predominant by the species of Nitrosomonas. The biological contact oxidation ditch (BCOD) system augmented with specialized bacteria can be a viable alternative for treating polluted stream water to achieve improved nitrogen removal.