水流注入方式和填料层高度对人工湿地流态的影响

Influence of Mode of Water Injection and Height of Packing Layer on Hydraulic Flow State of Constructed Wetland

流态模拟实验作为评价人工净化湿地系统运行状况、物质在其中停留时间的有效工具,在污水处理领域具有重要作用。罗丹明B背景浓度低、重现性好,被选为评价升流式、降流式和填料层高度对水力流态影响的示踪剂。实验使用罗丹明B和NaCl作为示踪剂,在湿地系统中进行流态实验,探究升流式、降流式和填料层高度对人工净化湿地流态的影响。实验结果表明,升流式人工湿地比降流式人工湿地处理效果好,示踪剂水力停留时间(hydraulic retention time,HRT)的体积利用率分别为82.0%和76.8%,升流式人工湿地无效体积中死区占更大比例,而降流式人工湿地滞留区占无效体积的比例更大;人工湿地填料层高度对示踪剂停留时间分布影响不大,体积利用率都在80%以上,但是,其死区和滞留区随着填料层高度的变化在无效体积中所占的比例有所差异,死区所占的比例随着填料层高度的增加先增加后减少,滞留区所占的比例则先减少后增加。

As an efficient tool in the evaluation of the operational process and material reaction time in the con- structed wetland, hydraulic simulation experiment plays a significant role in wastewater treatment. The hy- draulic simulation was carried by using NaC1 and Rodin Ming B as the tracer agents in the wetland system, which Rodin Ming B was selected as the tracer agent to appraise the lifting and lowering flow and the hydrau- lic flow state of packing layer height for the lower background density and the better reproduction quality. It was showed that the up-flow system has a better effect than the down-flow system in this experiment. The vol- ume utilization ratios of hydraulic retention time were 82% and 76.8% respectively. In the invalid volume the dead area accounted for a greater proportion in up-flow system, while the detention area accounted for the greater proportion in down-flow system. The height of packing layer had little influence on the distribution of the resident time for the utilization ratio of volume was above 80%, however, the proportion of the dead area and the detention area in the invalid volume varied with height of packing layer in the constructed wetland. With the increase of height of packing layer, the dead area increased and then decreased, but the detention area first decreased and then increased.