Impact resistance of different factors on ammonia removal by heterotrophic nitrification–aerobic denitrification bacterium Aeromonas sp. HN-02

To give reference for the application of heterotrophic nitrification–aerobic denitrification bacteria in actual wastewater treatment, the impact resistance of extreme pH, low temperature, heavy metals and high salinity on ammonia removal by a typical heterotrophic nitrifying–aerobic denitrifying bacterium Aeromonas sp. HN-02 was investigated. The results showed that HN-02 demonstrated strong acid- and alkali-resistance. In addition, it remained active at 5 °C, and the removal rates of ammonia and COD were 0.90 mg L−1 h−1 and 22.34 mg L−1 h−1, respectively. Under the same extent of immediate temperature drop, the temperature correction coefficients of ammonia, COD removal rates and cell growth rate were close. Moreover, HN-02 could survive in the solution containing 0.5 mg L−1 Cu2+ or 8 mg L−1 Zn2+, or 0.5 mg L−1 of equivalent Cu2+–Zn2+. Furthermore, efficient ammonia removal was retained at salinity below 20 g L−1, thus it could be identified as a halotolerant bacterium. At last, stronger stress resulted in higher ΔCOD/ΔTN ratio.