Effect and Mechanism of Removal of Nitrogen in the Mimic Sewage Using Bio-zeolite System
生物沸石床污水脱氮效果及机理

On the spot, the removal effect of pollutants such as NH3-N, N, NO3(-)-N, NO2-(-)N, TN and COD in the mimic sewage by bio-zeolite system was studied. The following results were obtained: it was obvious and stable for the removal of NH3-N by bio-zeolite with a removal efficiency over 95%, but the removal effect of NO3(-)-N was affected deeply by hydraulic retention time, according to the different removal mechanism; chemical adsorption and ion exchange were the main reasons for the removal of NH3-N as well as nitrification by microbe, while denitrification was the main reason for the removal of NO3(-)-N. Nitrification intensity of bio-zeolite was affected by the concentration of dissolved oxygen in the solution, so the nitrification intensity of bio-zeolite on the surface of the zeolite bed was two times of that in the middle in vertical direction. Denitrification intensity changed with different values of C/N in the study, and it could reach the maximum while COD/TN was 5; as for denitrification velocity, it was largest in the first six hour.