多级串联潜流人工湿地净化城市地面径流的试验研究

在室外露天试验场按不同水流方式设计和建造2组多级串联潜流人工湿地,通过中型试验测试其在不同运行方式下对西安市地面径流中COD、NH4+-N、TN、TP的净化效果。结果表明:2组人工湿地系统出水水质均达到GB 3838-2002《地表水环境质量标准》Ⅳ类标准;在湿地净化过程中,填料起主要作用,可吸附40%～50%的污染物,植物和微生物的协同作用可将净化效果提高20%～30%;2种人工湿地系统HRT为36～48h,运行间隔时间为7～15d的运行效果最佳;改变水流方式的复合流人工湿地系统净化效果优于水平潜流人工湿地系统,净化效果高出5%左右。研究设计的2种人工湿地均可用于城市地面径流污染的控制和雨水利用。

Experimental Study on Multil-series Subsurface Flow Constructed Wetlands Purifying Urban Surface Runoff

Two multilevel series subsurface flow constructed wetlands(MS-SFCW) of different flow styles were designed and constructed in the outdoor open experimental field.The measured data of medium-sized experiments were used to determine the purification effect of MS-SFCW on COD,TN,NH+4-N and TP in the Xi’an surface runoff,and the relationship between influencing factors and purification effect is analyzed.Results show that: The effluent quality of two MS-SFCWs system is totally within the range of Ⅳ kind water quality of ’surface water environmental quality standards’(GB 3838-2002).In the purification process of constructed wetlands,packing material plays a leading role,which can remove 40%~50% of the pollutants,and the purification effect can be improved 20%～30% with the synergistic effect of plants and microorganism.When HRT is 36 h to 48 h,and the headway days is 7 d to 15 d,the two MS-SFCWs can achieve the best operation effect.The purification effect of multi-flow constructed wetlands changing flow style is better than horizontal subsurface flow constructed wetlands,and the purification effect of the former is higher 5% than the latter.The designed two MS-SFCWs can be used to control urban surface runoff pollution and use rainwater.