不同流态和基质对人工湿地污染物去除及温室气体排放的影响研究

Effect of Flow Pattern and Matrix on Contaminant Removal and Greenhouse Gas Emissions of Constructed Wetlands

为研究流态和基质对人工湿地生态系统功能的影响,分别利用水平推流砾石潜流湿地、水平推流陶粒潜流湿地、水平折流砾石潜流湿地、上下折流砾石潜流湿地4种人工湿地装置处理低污染水,考察不同流态和基质对人工湿地污染物去除及温室气体排放的影响。结果表明:上下折流砾石潜流湿地对污染物的处理效果最好,对CODMn、TP、TN、NO_3-N、NH_4-N的去除率分别达到20.78%、42.47%、28.9%、32.72%和52.92%,并且该湿地的CO_2和N_2O排放通量最大,分别为409.3mg/(m2·h)和20.3mg/(m^2·h),水平折流砾石潜流湿地的CH4排放通量最大,为0.80mg/(m^2·h),说明流态对人工湿地污染物的处理效率及温室气体排放具有重要影响,采用上下折流流态的人工湿地具有更高的污染物处理效率及温室气体排放通量;水平推流陶粒人工湿地对CODMn、TP和NH_4^+-N的去除率分别为24.39%、29.44%和22.39%,高于水平推流砾石人工湿地的去除率(14.71%、37.19%和12.23%),说明相比砾石,以陶粒作为基质的人工期湿地具有更高的污染物处理能力。

To study the effect of flow pattern and matrix on ecosystem functions of constructed wetlands,this paper establishes four constructed wetland apparatus to treat slightly contaminated water in order to investigate the impacts of flow pattern and matrix on contaminant removal and greenhouse gas emissions of constructed wetlands.The flow pattern as well as the matrix of the four constructed wetlands are horizontal push flow with gravel matrix,horizontal push flow with ceramic matrix,horizontal baffle flow with gravel matrix,and vertical baffle flow with gravel matrix,respectively.The results indicate that the constructed wetland with vertical baffle flow and gravel matrix has the best contaminant removal rates,which are 20.78%,42.47%,28.92%,32.72%and 52.92%for CODMn,TP,TN,NO_3-N and NH_4-N respectively.At the same time,its emission fluxes of the carbon dioxide（CO_2）and methane（CH_4）are also the highest,which reach 409.3mg/（m^2·h）and 20.3mg/（m^2·h）,respectively.Whereas for nitrous oxide（N_2O）,the constructed wetland with horizontal baffle flow and gravel matrix discharges the highest with the emission fluxes being 0.80mg/（m^2·h）.The paper shows that flow pattern has a profound effect on treatment efficiency and greenhouse gas emissions of constructed wetlands,and the constructed wetland with vertical baffle flow leads to a higher treatment efficiency of contaminants as well as greenhouse gas emission fluxes.The removal rates of the constructed wetland with horizontal push flow and ceramic matrix are24.39%,29.44%and 22.39%for CODMn,TP and NH_4-N respectively.They are higher than those with horizontal push flow and gravel matrix,which are 14.71%,37.19%and 12.23%respectively.It indicated that the constructed wetland with ceramic matrix has better contamination removal ability than that with gravel matrix.