Furthermore, the 16S rDNA sequences of two clone libraries were combined to analyze the relationship of bacterial communities between the two reactors, which were presented in a figure of taxonomic classification (Fig. 5). The results showed that the bacterial communities were distinctively different from each other. The bacterial community in the control reactor was dominated by Bacterodietes (25%), Acidobacteria (18.8%), Planctomycetes (16.7%) and Proteobacteria (10.4%). However, the abundance of phylum Acidobacteria was decreased significantly after bio augmentation (3.92%).