潜流型人工湿地基质堵塞特性试验研究

为解决设计不当或管理不善等原因造成的湿地堵塞问题,深入揭示湿地堵塞特性及形成机制,试验研究了芦苇潜流型水平流湿地和垂直流湿地的堵塞特性,并以此比较了2种湿地长期运行的稳定性.结果表明,湿地堵塞后土壤中有机质积累量较大,在湿地中各测量点达到了1.5%～5%,其主要积累区域在湿地前部表层,积累量为4%～5%,对有机物积累量与土壤深度进行数值分析发现,两者之间呈显著函数关系;水平流湿地和垂直流湿地内部堵塞机制不同,故堵塞后水平流湿地水力停留时间为3.515 4 d,较正常值缩短21.88%,而堵塞垂直流湿地水力停留时间为5.464 8 d,较正常值增长21.44%.湿地堵塞后污染物去除效率明显降低,波动较大,2种湿地比较发现,垂直流湿地的堵塞情况较水平流湿地更为严重.

Clogging Characteristics of the Subsurface Flow Wetland

In order to resolve clogging problem of constructed wetlands caused by improper design or imperfect management and reveal the clogging mechanism, clogging characteristics of the horizontal flow reed wetland and vertical flow reed wetland were studied. Operation stabilities of two types of wetlands were compared. It shows that organic matter accumulates in medium and the concentration is 1.5 % - 5 %. It mostly occurs in the fore section of top layer in wetland and the concentration is 4% - 5%. The negative correlation between the organic matter content and the subsurface depth was demonstrated. The clogging mechanisms in the horizontal flow wetland and the vertical flow wetland are different. The hydraulic retention time of the horizontal flow wetland is 3.515 4 d which is shortened by 21.88%. While the hydraulic retention time of the vertical flow wetland is 5.464 8 d and extended by 21.44%. The results indicate that clogging decreases the treatment capacity and running stability conspicuously. The clogging phenomenon of the vertical flow wetland is worse comparatively.