Nitrogen Removal by Bacillus sp. LY with Heterotrophic Nitrification Ability
异养硝化细菌Bacillus sp. LY脱氮性能研究

Bacillus sp. LY has the ability of nitrogen removal. Under the NH+4-N load of 40, 80 and 120 mg/L, after 120 hours culture, the NH+4-N removal rate finally was 100%, 85.7%, 73.7%, and the removal rate of TN finally was 76.6%, 53.4%, 64.8%. As the concentration of ammonium improved, the rate of nitrification and the nitrogen removal would decrease under the same concentration of Bacillus sp. LY at the beginning. The concentration of organic material played an important role in the nitrogen removal by Bacillus sp. LY. The low concentration of organic material inhibited the ability of nitrogen removal, and the middle concentration of organic material enhanced its ability of nitrogen removal and reached the optimum nitrogen removal condition, but the high concentration of organic material did not enhance its ability of nitrogen removal again. Organic nitrogen could be transformed to ammonium by Bacillus sp. LY, which was then transformed to N2 through two possible pathways. One pathway was a nitrification process followed by a denitrification process. The other pathway was that ammonium was first oxidized to hydroxylamine, then dehydrogenized to N2O and finally transformed to N2. All these results may contribute to the establishment of new biology process to remove nitrogen with high efficiency.