Identification of an Aerobic Denitrifier and Its Denitrification Characteristics

LI Xue1, LIU Sitong2, CHEN Qian2,†

1. School of Chemistry and Environmental Engineering, Lanzhou City University, Lanzhou 730070; 2. Beijing Engineering Research Center of Advanced Wastewater Treatment, Department of Environmental Engineering, Peking University, Beijing 100871; † Corresponding author, E-mail: qianchen@pku.edu.cn

Abstract Strain HG-7 was identified as Pseudomonas sp. through 16s RRNA gene sequence analysis. The aerobic denitrification ability of strain HG-7 was further proved by the existence of the napa and nirk genes. Further studies showed that the optimal carbon resources for strain HG-7 were sodium acetate and sodium succinate, the optimal C/N ratio was 6 10, and the suitable temperature was 26 30℃. At this condition, with an initial nitrate nitrogen of 100 mg/l, 98% of nitrate could be removed in 48 hours and the amount of nitrite accumulation was very small. Moreover, with nitrite as the sole nitrogen source, 100% of nitrite could be removed at lower nitrite concentration. But the nitrite nitrogen removal rate was about 40% when the nitrite concentration increased to 91.4 mg/l, indicating that high nitrite concentration was harmful for aerobic denitrification by strain HG-7. The strain HG-7 has great potential to be used for biological nitrogen removal, which was particularly significant for actual wastewater treatment processes. Key words aerobic denitrifier; identification; nitrogen characteristics