Six complex microbial inoculants for removing ammonia nitrogen from waters

To determine the effect of microbial inoculants on the removal of ammonia nitrogen (NH4+‐N), six different complex microbial inoculants were studied. In this study, their effectiveness on NH4+‐N removal was compared, and their microbial community composition was determined. High‐throughput sequencing results showed that Proteobacteria and Firmicutes were the dominant phyla in six samples. Before the reaction, Bacillus, Cyanobacteria, and Mitochondria genera were the dominant genera. The dominant genera were significantly different after the reaction with the addition of bacterial agents. The six water samples were Massilia, Escherichia‐Shigella, Brevibacillus, Mitsuaria, Bacillus, and Ralstonia. Among the six complex microbial inoculants, “Gandu nitrifying bacteria (NR4)” have the best removal effect on NH4+‐N. In addition, the removal effect of six different bacterial agents on chemical oxygen demand (COD) was compared. The results showed that “Bilaiqing ammonia nitrogen removal bacteria agent (NR5)” has the best removal effect on COD. Single‐factor experiments suggested that the optimal conditions for NR4 bacteria were pH 7, 30°C, 1.0 g/L of bacterial agent dosage and a wide range of NH4+‐N from 30 to 300 mg/L.