Study on pollution characteristics of urban pavement runoff

Urban pavement runoff has become an important pollution source to endanger the quality of urban water. This paper analyzed the characteristics of particle size distribution of road-deposited sediment (RDS). The variation of pollutants contented with RDS was presented. Based on continuous sampling of runoff, the variation between pollutant concentration and rainfall characteristics was revealed. The results show that each particle group shares similar content except for the group smaller than 0.075 mm. However, the smaller particles have the stronger ability to adsorb heavy metals (Zn, Pb, Cu), and the weaker ability to adsorb Chemical Oxygen Demand (COD). The concentrations of different pollutants have different relationships with rainfall and runoff time. The concentration of suspended solids (SS) decreases monotonously with runoff time, while the concentration of heavy metals increases first and then decreases. The first 30 minutes of runoff is the best time to treat heavy metals and SS. And the five-day biochemical oxygen demand (BOD5) and total petroleum hydrocarbons (TPHs) concentration are mainly affected by rainfall intensity. The result presented in this paper may provide a useful reference for the treatment of pavement runoff pollution.