水力停留时间变化对2种人工湿地净化效果的影响

依托建立在新沂河河漫滩的人工湿地中试工程开展现场实验,研究分析水力停留时间变化对2种人工湿地污染物净化效果的影响。结果表明:水力停留时间的变化显著影响潜流和垂直流湿地污染物净化的效果,2种湿地高锰酸盐指数和氨氮(NH4+-N)去除效果随水力停留时间的变化均呈现先上升后下降的趋势。垂直流人工湿地显示出比潜流湿地更好、更稳定的污染物净化效果,其高锰酸盐指数和NH4+-N去除效果的最佳停留时间均出现在2 d左右,2种污染物的去除率分别达到93.1%和87.7%;而潜流湿地在水力停留时间为2 d左右时高锰酸盐指数去除率最高,达到92.3%,在2.5 d左右的时候NH4+-N去除率最高,达到81.5%。潜流和垂直流湿地都适合应用于新沂河污染河水的处理,在设计和实践应用中,两者的水力停留时间参数均可设定为2 d。

Influence of hydraulic retention time variation on purification effects of two different constructed wetlands

Based on the pilot-scale field experiment of constructed wetland on the riverside of Xinyi River,the relationship between hydraulic retention time variation and purification effect of two different constructed wetlands was studied.It is showed that hydraulic retention time variation significantly influenced purification effect of subsurface flow constructed wetland (SSFW) and vertical flow constructed wetland (VFW).With the variation of hydraulic retention time,potassium permanganate index (COD_Mn) and ammonia nitrogen (NH₄⁺-N) removal effect increased,and then declined.The purification effect of VFW was better and more stable than SSFW.For both wetlands,the best retention time for COD_Mn and NH₄⁺-N removal effect appeared about 2 d.The removal rates were 93.1% and 87.7%,respectively.However,for SSFW,the best hydraulic retention time of COD_Mn removal was about 2 d,and the removal rate was 92.3%.The best retention time for NH₄⁺-N removal was about 2.5 d,the removal rate was 81.5% accordingly.SSFW and VFW are both suitable for Xinyi River pollution treatment;the best hydraulic retention time of both wetlands can be set as 2 d.