Nitrogen removal and N 2 O emission from water purification process by immobilized nitrogen cycling bacteria in urban lake

The process of water purification was studied using immobilized nitrogen cycling bacteria, including ammonibacteria, nitrosobacteria, nitrifying bacteria and denitrifying bacteria, which applied and screened for natural water of Lake Jinshan. The result showed that the water quality was improved obviously after running a period of time. Concentrations of NH4+-N, NO2--N, NO3--N and TN declined. NH4+-N concentration had reached national Ⅰ class of water quality index. TN concentration had reached Ⅱclass. The N2O flux of Lake Jinshan increased during three months from April to June, which were 23.51μg/(m2·h), 29.52μg/(m2·h) and 59.10μg/(m2·h) respectively. The experiment has proved that the techniques of immobilized nitrogen cycling bacteria could purify the urban lakes significantly.