To achieve effective removal of various inorganic nitrogen in aquatic ecosystems, while expanding the applicability of existing heterotrophic nitrifying-aerobic denitrifying (HN-AD) strains and enhancing their stress tolerance, we isolated the Pseudomonas aeruginosa WS-03 from a sewage treatment plant. The results of parameter optimization indicated that the following were the most favorable conditions for nitrogen removal: using sodium citrate as the carbon source, a C/N ratio of 9, a pH of 7, a temperature of 30 °C and an NH