Effects Of Operating Conditions On Microbial Consortium Of The Heterotrophic Ammonia Oxidation Process

This study aimed to investigate the ammonia removal by the consortium mainly comprising of ammonia-oxidizing bacteria under different initial pH, temperatures and stress of heavy metals. The results showed that the consortium exhibited a strong adaptation for broad pH ranging from 5 to 9. When the temperature dropped to 15 degrees C, its ammonium removal and nitrate accumulation rates decreased by 72.23% and 95.12%, respectively. Meanwhile, the temperature correction coefficients of the ammonium removal and nitrate accumulation rates reached the maximum. In addition, the consortium could survive in the solutions containing 0-1.0 mg.L-1 Cu2+ and 0-5.0 mg.L-1 Fe3+. Moreover, the inhibition of free nitrous acid (FNA) against nitrite oxidation activity was found to be much more significant than that low-temperature treatment. Microbial diversity analysis showed that the bacterial community structure was shift significantly by the temperature drop, especially change the abundance of Nitrosomonas, Paracoccus, Pseudomonas and Nitrospirae.