深床过滤用于垂直流人工湿地净化效果研究

Study on the Purification Performance of Deep-bed Filtration Vertical Flow Constructed Wetland

针对人工湿地占地面积大的实际问题,将深床过滤原理引入垂直流人工湿地,在连续流工况下,研究深床过滤型垂直流人工湿地(床深1.5 m,记为C系统)相对于常规中床(1.0 m,B系统)和浅床(0.5 m,A系统)湿地对污染物的净化效果。结果表明,C系统相对B系统,显著提升了COD、TP和浊度去除率(p<0.05),极显著提升了NH_4^+-N降解率(p<0.01);相对A系统,显著提升了TN去除率,极显著提升了TP,NH_4^+-N和浊度去除率。湿地基质深度x(m)与出水对浊度和TP的去除率y(%)间存在正线性相关性,关系式分别为:y=13.65x+68.613(R^2=0.923 8)和y=22.44x+32.84(R^2=0.993 6)。因此,深床过滤型垂直流人工湿地能有效提高污染物综合净化效果,增加湿地处理水力负荷,减小占地面积。

Concerning on the problem of large area occupied for constructed wetlands, the deep-bed filtration theory was introduced into the vertical flow constructed wetland(VFCW). Purification effects of the deep-bed filtration VFCW(as sys-tem C) compared with the 1.0 m-deep(system B) and 0.5 m-deep VFCWs(system A) under continuous flow condition was studied. The results showed that compared with system B, system C significantly improved the degradation rate of COD, TP and turbidity(p<0.05), and extremely significantly increased the removal rate of NH_4^+-N(p<0.01). Compared with system A,the removal rate of TN of system C was significantly improved, and the degradation rate of TP, NH_4^+-N and turbidity was extremely significantly improved. Besides, there exists a positive linear correlation between the substrate depth x(unit: m) of the constructed wetland and its turbidity and TP removal rates y(unit: %), the equations are y=13.65 x+68.613(R^2= 0.923 8) and y=22.44 x+32.84(R^2= 0.993 6) respectively. Therefore, the deep-bed filtration VFCW can effectively improve the purification effect of pollutants, thus increase the hydraulic load and reduce the construction area of the wetland.