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 degrees 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 DCOD/DTN ratio. (C) 2014 Elsevier Ltd. All rights reserved.