污水浓度对高原湖泊人工湿地处理率的影响研究

Study on the effect of sewage concentration on treatment efficiency of artificial wetland of plateau lake

通过改变表流和潜流人工湿地的进水总磷(TP)、总氮(TN)的浓度,采用6种湿地植物(紫叶美人蕉、水葱、水葫芦、水芹菜、菖蒲、芦苇)的对比实验,对比分析了6种不同植物的表流和潜流人工湿地处理率随浓度变化的规律,得到了6种不同植物的表流和潜流人工湿地的理论最优处理浓度、理论最优去除率、实际最优处理浓度、实际最优去除率和TP、TN最大日处理负荷。实验结果表明:六种植物的表流和潜流人工湿地对TP、TN去除率随着浓度的增加而降低,植物不同,处理率降低程度不同,且潜流比表流去除率降低值小。水葫芦去除率随TP浓度增加变化不大,表流处理率降低1.61%,潜流降低1.12%;美人蕉变化较明显,表流处理率降低2.94%,潜流降低了2.55%;随TN浓度增加,紫叶美人蕉去除率降低最小,表流处理率降低17.07%,潜流降低15.94%;芦苇去除率降低较明显,表流处理率降低20.86%,潜流降低18.20%。同时,根据实验结果得到6种植物表流人工湿地最大日TP去除量为60.16g(m-2.d-1);潜流人工湿地最大日TP去除量为81.50g(m-2.d-1)。表流人工湿地最大日TN去除量为547.20g(m-2.d-1);潜流人工湿地最大日TN去除量为577.60g(m-2.d-1)。

Comparative experiments were conducted for six plant species （purple leaf canna, water onion, water hyacinth, water celery, calamus, reed as listed in Table 6） and two types of flows （surface flow and subsurface flow） by adjusting TP and TN concentrations of sewage flow into artificial wetlands of plateau lake. Variations of wetlands treatment rate with sewage concentration were compared and analyzed, and theoretically optimal concentration and removal rate, actual optimal concentration and removal rate, and peak daily load of TP and TN processing, were obtained. Results show that the removal rates decrease as sewage concentration increases, and that removal for subsurface flow is slower than surface flow. These decreases vary significantly with different wetland species. As the TP concentration increases, the decreases for water hyacinth are 1.61% and 1.12% for surface and subsurface flows, respectively, canna 2.94% and 2.55% , purple leaf 17.07% and 15.94%, and reed 20. 86% and 18.20%. The peak daily TP removals of six species are 60. 16g（m^-2·d^-1） and 60. 16g（m^-2·d^-1） for surface and subsurface flows, respectively, and the TN removals 547.20g（m^-2·d^-1） and 577.60g（m^-2·d^-1 ）.