对城市中典型的2种材料(油毡和水泥)屋面降雨径流中颗粒物(SS) 、氮(N)和磷(P)污染物排放特征进行了研究。结果表明,屋面径流中颗粒物主要是以10 ~ 100 μm粒径范围的颗粒物为主(约占75%), 氮主要是以溶解态形式排放(80% ~ 95%), 且主要形式是以硝态氮和氨态氮为主,水泥屋面增加了径流中硝态氮的比例,而沥青屋面增加了氨态氮和溶解态有机氮的比例。而磷主要是以颗粒物形态排放(约占40% ~ 70%,平均57.5%), 且主要结合10 ~ 50 μm粒径范围的颗粒物。去除10 ~ 50 μm粒径颗粒物可以降低屋面径流中50%颗粒物和47.9%磷的排放,而氮却需采用不同处理方法。同时,EC和TSS与TN和TP相关关系表明,EC和TSS可分别作为屋面降雨径流溶解态氮和颗粒态磷污染程度检测和评价指示指标。研究结果为有效地去除降雨径流中污染物、降低城市面源污染对水环境的影响,提供了一定的科学依据。

This study investigated the emissions characteristics of pollutant materials (suspended solids (SS), nitrogen (N), and phosphorus (P)) in runoff from two,typical roof surface types in urban areas: cement and asphalt. The results indicated that more than 75% of the SS particles were in the size range of 10 to 100 μm. 80% to 95% of the N was dissolved (< 0.45 μm), and the main forms of N in the roof runoff were nitrate and ammoniacal-N. However,the cement roof increased the proportion of nitrate-N,and the asphalt roof increased the percentage of ammoniacal-N and dissolved organic N. 70% to 90% of the P was in particulate form in the roof runoff,and P was attached mainly to particle sizes between 10 and 50 μm. The removal of the 10 to 50 μm particles reduced the SS and P emissions from roof runoff by 50% and 47.9%,respectively. Different strategies should be applied to control N pollution to minimize the environmental impact of urban roof runoff. EC and TSS could be used as surrogates for the dissolved N and particulate P forms,respectively,in the monitoring and evaluation of the pollution in urban roof runoff. It is important to have a clear understanding of the pollutants'wash- off behavior to remove effectively urban nonpoint source pollution and prevent stormwater pollution in urban environments.