处理低污染水的复合人工湿地脱氮过程

为了解人工湿地处理低污染水的脱氮过程,以洱海流域邓北桥湿地为例,采用水质分析、细菌数量分析与硝化/反硝化强度分析相结合的方法,研究了复合型人工湿地处理低污染河水过程中的氮转化过程及污染物去除效果. 结果表明:在氧化塘-表流湿地-潜流湿地-表流湿地的复合型人工湿地中,ρ(NH₃-N)和ρ(TN)呈逐级降低的趋势,NH₃-N和TN的平均去除率分别可达53.24%和48.21%. 氧化塘和表流湿地的硝化强度显著高于潜流湿地,二级表流湿地中硝酸菌数量和表层硝化强度均为各工艺单元中最高的,分别为93.00×105g-1和8.42×102mg/(m3·h)；潜流湿地中ρ(DO)较低,其反硝化作用强度为各单元最高的,其中表层反硝化强度为32.70×102mg/(m3·h),深层反硝化强度为32.09×102mg/(m3·h). 该复合型人工湿地中反硝化的主要单元为潜流湿地. 

Study on Nitrogen Removal Process of Treatments for Slightly Contaminated Water on Hybrid Constructed Wetlands

In order to study nitrogen removal process of treatments for the slightly contaminated water on hybrid constructed wetlands, three indicators including nitrogen concentration, bacteria quantity and intensity of nitrification/denitrification were analyzed in the Dengbeiqiao wetland system. Meanwhile, the process of nitrogen variation and the removal rate were discussed. The results showed that the concentration of NH₃-N and TN stepwisely decreased in this hrbrid system of oxidation pond-surface flow-subsurface flow-surface flow wetland. Removal rates of NH₃-N and TN reached for 53.24% and 48.21% in average respectively. Intensity of nitrification in the oxidation pond and in the surface flow wetland were much higher than those in the subsurface flow wetland; The final surface flow wetland owns the greatest amount of nitrate bacteria (93.00×105g-1) and the highest intensity of nitrification (8.42×102mg/(m3·h) in the surface soil); while DO on the subsurface flow wetland is the lowest, and intensity of denitrification in the surface and the deep soil reached for 32.70×102and 32.09×102mg/(m3·h), respectively. The primary unit of denitrification on hybrid constructed wetlands is the subsurface flow wetland.