一次连续降雨过程中氨氮在不同介质中迁移模拟柱实验

氨氮在包气带中迁移与介质含水量多少有关。自然界中,降雨是影响介质含水量多少和运移的主要因素。通过动态土柱实验模拟降雨过程中氨氮迁移规律。结果表明,降雨时包气带处于饱和状态,氨氮下移平均速率10 cm/5 h,明显比非降雨情况污染扩散速度高1个量级。降雨后包气带处于非饱和状态,介质可固定氨氮。粗颗粒中氨氮浓度变化稳定;细颗粒中氨氮浓度缓慢减少。72 h连续实验,浅层氨氮达到吸附平衡,深层未达到吸附平衡,粗颗粒吸附速率慢于细颗粒。

Experimental Study on Ammonia Nitrogen Transport in Different Medium in Rainfall Process

Ammonia nitrogen transport in unsaturated zone is related to water content. In nature, rain is major factor in water content and transport. Through dynamic column experiment, this paper simulates ammonia nitrogen transport law in rainfall process. The results show that when aerated zone is saturated in rainfall, down infiltration average speed of ammonia nitrogen is 10cm/5h, which speed is much quicker than non-rainfall . After rainfall, aerated zone is unsaturated and it can fix ammonia nitrogen. In big particle medium, ammonia nitrogen concentration varies stably, while in small particle medium it decreases slowly. In 72 hours continuous experiment, ammonia nitrogen has reached adsorption equilibrium in shallow layer,while has not reached adsorption equilibrium in deep layer. Adsorption rate of big particle medium is slower than small one.