Orthogonal Test Design to Optimize on Ammonium Removal by Pseudomonas stutzeri ZH-1

To give reference for the application of nitrobacteria in actual wastewater treatment, the impact factors of C/N ratio, shaking speed (DO) and carbon source on ammonium removal by Pseudomonas stutzeri ZH-1 was investigated. Through orthogonal test, the optimal conditions for NH4+-N removal were C/N 12, shaking speed 100 r/min and sodium citrate as carbon source. The strain ZH-1 exhibited efficient nitrifying ability and maximum NH4+-N removal efficiencies were 99.66%, and removal rate was 4.27 mg L-1h-1. The results demonstrated that C/N and DO were the most important factors influencing the performance of heterotrophic nitrification. Also, these findings stated that the strain ZH-1 might be an effective and suitable candidate for ammonium nitrogen removal in industrial wastewater treatment.