生物沸石床污水脱氮效果及机理

研究了生物沸石床对模拟村镇生活污水中各形态氮及COD等污染物的去除效果结果表明,生物沸石床对NH₃^--N去除效果明显且稳定,去除率大于95%,对NO₃^--N的去除则受水力停留时间的影响较大从机理分析,生物沸石对NH₃-N的去除主要依靠化学吸附、离子交换以及生物硝化的协同作用,而对NO₃^--N的去除主要依赖反硝化作用.生物沸石的硝化作用明显,并受溶解氧浓度限制,沸石床中部沸石硝化强度只有表层沸石的1/2;其反硝化能力则随实验条件中C/N的不同而变化明显,当COD/TN=5时,反硝化作用最强,在时间变化规律上,前6h反硝化速率最大.

Effect and Mechanism of Removal of Nitrogen in the Mimic Sewage Using Bio-zeolite System

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.