人工湿地对水体悬浮泥沙的影响

Effects of Constructed Wetland on Suspended Sediment

根据自然水体湿生植物(挺水植物)、浮叶植物以及沉水植物的空间分布规律,利用水生高等植物菖蒲(Acorus calamus)、菱(Trapa incisa)、黑藻(Hydrilla verticillata)、苦草(Vallisneria spiralis)和狐尾藻(Myriophyllum spicatum)构建的阶梯式人工湿地,定量化研究了植物群落对不同浓度悬浮泥沙水体在不同水力停留时间下的影响,并对输入悬浮泥沙浓度、输出悬浮泥沙浓度、水力停留时间等参数进行了比较分析。结果表明:(1)输入悬浮泥沙浓度依次为98.69,191.76,273.13 mg/L,平均为187.76 mg/L,流经人工湿地植物群落后,输出植物组的水体悬浮泥沙平均浓度为26.52 mg/L,为对照组平均浓度51.96 mg/L的51.04%;(2)输出人工湿地的悬浮泥沙浓度随输入悬浮物浓度的增加而增加,随水力停留时间的延长而降低,回归方程为Cplant out=1.231+0.170Cin-0.356H;(3)试验水体中滞留的悬浮泥沙浓度随输入悬浮物浓度的增加而增加,随水力停留时间的延长而减小,回归方程为Cplant water=1.158+0.261Cin-0.623H;(4)悬浮泥沙在人工湿地中的沉降量随输入悬浮物浓度的增加和水力停留时间的延长而增加,回归方程为Wplant=0.810Cin+0.886H-2.340;(5)要维持人工湿地沉水植物生长需要的透明度条件,输入悬浮泥沙浓度(Cin)与最小水力停留时间(Hmin)要满足如下关系:Hmin=0.419Cin-38.478(98.7<Cin<273.1)。

In the research, in order to quantified study effects of plant communities on sandy waters contained different suspended sediment （SS） concentrations in different hydraulic retention time （HRT）, a step constructed wetland of emerging plants, floating-leaved plants and submerged plants which based on spatial distribution of natural layer body were constructed by aquatic marcrophytes, such as Acorus calamus, Trapa incisa, Hydrilla verticillata, Vallisneria spiralis and Myriophyllum spicatum. A comparative analysis of input SS concentrations, output SS concentrations and HRT was also done. The results were as follows： （1） The input SS concentrations are 98.69,191.76,273.13 mg/L, average of 187.76 mg/L and the output average SS concentration is 26.52 mg/ L, just 51.04% of the comparison treatment; （2） The output SS concentrations increase with increase of the input SS concentrations and decrease with protracting of HRT. The regression equation is Cplant cut= 1. 231-1-0. 170 Cin - 0. 356/-/; （3） The retained SS concentrations in the experimental water increase with increase of the input SS concentrations and decrease with protracting of HRT. The regression equation is Cplant water = 1. 158＋0. 261 Cin 0. 623H; （4） The sedimentations of SS in constructed wetland increase with increase of the input SS concentrations and protracting of HRT. The regression equation is Wplant =0. 810 Cin, ＋ 0. 886H -2.340; （5） In order to keep transparency condition needed by emerging plants growth of constructed wetland, the relationship between the input SS concentrations and the minimum HRT must be： Hmin = 0. 419 Cin- 38. 478（98. 7 〈 Cin 〈273.1）.