城市降雨径流人工湿地处理的效能研究

Efficiency study of improved constructed wetland for urban runoff treatment

根据广东省东莞市同沙水库集水区的降雨径流的平均水质特征,采用改进的人工湿地系统对其污染物的降解效果和耐冲击负荷能力进行了模拟研究,实验中人工模拟城市降雨径流污染物平均浓度COD为169.19 mg/L、TP为0.58 mg/L、TN为5.69 mg/L和NH4+-N为3.69 mg/L。实验结果表明,该湿地系统各对污染物均有较好的去除效果,分别为86.11%、82.1%、80.3%和76.7%;人工湿地对污染物的降解是由物理、化学和生物及其协同作用的过程。人工湿地沿程污染物浓度的变化实验结果表明,污染物在系统内的降解沿人工湿地水流方向逐渐降低,并且在系统前部达到主要去除效果。人工湿地在冲击负荷条件下的实验结果表明,该人工湿地能承受短时高浓度冲刷,耐冲击负荷能力强。

According to the characteristics of urban runoff in the catchment of Tongsha reservoir,Dongguan City,Guangdong Province,an improved constructed wetland was employed to treat the simulated runoff in terms of pollutant degradation efficiency and the capacity of shock loading.The average concentrations of COD,TP,TN,NH＋4-N in simulated wastewater were 169.19 mg/L,0.58 mg/L,5.69 mg/L,3.69 mg/L,and the removal efficiencies of the constructed wetlands system were 86.11%,82.1%,80.3% and 76.7%,respectively.The results indicated that the degradation process by the constructed wetlands was the synergistic effects of physical,chemical,and biological processes.The pollutant removal efficiency declined along the water flow direction,and most of pollutants were removed in the front of the system.The result of experiments under shock loadings revealed that the constructed wetlands had a strong resistance to shock loading,and it could bear short-term load of high concentration.