A hydrodynamic characteristic experiment was taken using a pilot plant of land treatment system.Experiment methods were used to research the applicability to land treatment system,and the tracer that the result of experiment showed the best reproducibility was selected.The results show that hydrodynamic characteristic of land treatment system is plug flow,the efficiency of volume is above 95%,and the degree of axial dispersion is medium.But the plant has stagnant volume.The experiment result using step method deviates the true hydrodynamic characteristic because density flow exists.When the pilot plant is practiced upflow,the up-step method could increase the mean residence time,better efficiency of plug flow and lower axial dispersion.Down-step method is different.When the pilot plant is practiced downflow,the down-step could increase the mean residence time and better efficiency of volume,but the up-step decrease.So the step method isn＇t suitable to land treatment system.When the experiment uses impulse method,Rhodamine B is better than NaCl because the result has more reproducibility and is more accurate.%在土地处理系统的反应器中进行流态试验,考察适用于土地处理系统流态试验的方法,并挑选重现性好的示踪剂.试验结果表明,土地处理系统水流流态为推流式,体积效率达到95%以上,轴向扩散属于中等分散程度,但存在一定的滞留区.采用阶跃法进行流态试验会由于异重流的影响使试验结果不能反映出反应器的真实流态：采用升流式运行,升阶法会增加平均停留时间,具有很好的推流效果和很低的扩散系数,降阶法则相反;降流式运行,降阶法增加了平均停留时间,有更大的体积效率,升阶法则降低了水流推流效果.因而阶跃法不适合土地处理系统的流态试验.脉冲法采用罗丹明B作为示踪剂的试验结果比NaCl具有更好的重现性、更加准确.
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