河水受百年一遇大旱后城市降雨径流的污染与治理

Study on the pollution of urban rainfall runoff to river water after the once-in-a-century drought

2009年入秋至2010年春,中国西南地区发生了百年一遇的特大旱灾。为探讨河水受百年一遇大旱后降雨径流污染的状况,对昆明典型交通干道路面的降雨径流和河水水质进行了监测,分析了大旱后降雨径流污染的严重性和对河水水质的影响,并考察了曝气塘—浮石床水平潜流人工湿地复合系统处理大旱后由城市降雨径流污染导致的重污染河水的效能。结果表明,大旱后的前3场降雨径流污染程度较正常雨季降雨径流污染程度严重,SS、COD、TN及TP浓度平均高出1.3倍。大旱后的前3场降雨径流溢流会对河流造成严重污染。该复合系统在塘调蓄—循环处理运行工况下能有效处理大旱后的重污染河水,对SS、COD、TP、TN和NH4+-N的平均去除率分别为98%、90%、96%、60%和90%,出水均达《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准。

The once-in-a-century drought hit Southwest China from the autumn of 2009 to the spring of 2010.The road runoff at major traffic road of Kunming（Xuefu Road） and river water in Kunming were monitored before and after the severe drought to investigate the influence of rainfall runoff on river water quality and the seriousness of the runoff pollution.Aerated pond and subsurface constructed wetland using pumice as substrate were combined to treat heavily polluted river water,the treatment efficiency was investigated.The results show that the pollution of the former three rainfall runoffs after the severe drought was about 1.3 times more serious than the rainfall runoffs in normal rainy season.The overflow runoff after the severe drought heavily polluted the river.The established system presented perfect performance for polluted river water treatment.The mean removal rates of SS,COD,TP,TN and NH＋4-N were 98%,90%,96%,60% and 90% respectively.The treated water met the standard A of grade I discharge standard of pollutants for municipal waste water treatment plant.