基质结构对水平潜流人工湿地净化效果影响

为研究基质填充结构变化对人工湿地净化效果的影响,构建2个不同基质结构的对比水平潜流人工湿地实验系统,对城市污水处理厂出水进行深度处理。实验结果表明,1～7 mm石英砂均混填充结构人工湿地系统对COD、NH4+-N和TP的平均去除率分别为49.5%,40.1%和56.1%;比较而言,1～7 mm石英砂分层填充结构湿地系统对3种污染物的平均去除率分别为53.7%,60.4%和68.6%。方差分析表明,不同石英砂结构的人工湿地对COD、NH4+-N及TP的净化效果差异显著(p<0.05)。此外,不同水力停留时间条件下,基质填充结构不同的湿地系统对以上3种污染物的净化效果也存在显著差异(p<0.05),去除率随着水力停留时间的增加而升高,当HRT为36 h时,各系统均能取得较好的净化效果。

Effect of substrate structure on purification performances of horizontal subsurface flow constructed wetlands

In order to investigate the effect of substrate structure on the pollutant removal performance of horizontal subsurface flow constructed wetlands (HSCWs),two pilot-scale HSCWs were constructed to treat the effluents of municipal wastewater treatment plants in parallel experiments.The experimental results showed that the COD,NH₄⁺-N and TP removal efficiencies of the HSCWs filled with well-mixed quartz sand (range 1~7 mm) were 49.5%,40.1% and 56.1%,respectively.In contrast,the HSCWs with multi-layered filling structure of quartz sand (range 1~7 mm) reached on an average 53.7%,60.4% and 68.6% for COD,NH₄⁺-N and TP,respectively.The statistical results showed that there was significant difference on all pollutants removal between the well-mixed substrate structure and multi-layered structure (p<0.05).Furthermore,significant difference among the various HRTs was also observed (p<0.05).The removal efficiencies increased with an increase of HRTs.It seemed that the 36 h HRT was adequate for acceptable removal efficiencies.