刚性植物对污染物输移扩散规律的研究

在矩形平底水槽中,用PVC圆柱棒模拟了刚性植物,用罗丹明溶液作为指示剂模拟了植物对污染物的输移扩散的影响。结果表明:污染物浓度垂向分布的最大值随时间的增加向水槽底部移动。这是因为植物的存在使水流的形态发生了改变,植物层水流的流速降低而滞留了水中的污染物质。污染物浓度梯度随时间的增加越来越小,浓度沿水深分布趋于均匀。这是因为植物增强了水流的紊动特性,污染物的垂向扩散作用增大,降低了下游水体污染物的浓度,控制了下游水体的污染状况。

Study on the effect of rigid vegetation on the pollutant transportin open channels

In the study of the effects of vegetation on the pollutant transport,PVC cylindrical rods aresimulated as rigid plants and Rhodamine is adopted as tracer substance.The experiments were conductedon a rectangular flume.The result shows that the maximum of concentration of contaminants invertical direction moves to the bottom of the tank with the time goes on.Because of the plants,theflow structure change and the velocity in the plant layer decrease.So contaminants can be detained inthe areas of vegetation.Concentration gradient becomes smaller and smaller with the time goes on andthe distribution of concentration is uniform.Turbulent flow effect will be enhanced under the conditionsof vegetation,increasing the vertical diffusion of pollutants,decreasing the concentration ofdownstream contaminants.So the downstream water pollution is under control.