A comprehensive analysis of storm water pollutants generation from urban roadway in Korea

Abstract

This study investigated the pollutants generation carried by urban storm water in Korea, with focuses on the first flush and the role of particles on pollutants transport. A series of field experiments were performed at an entry ramp of local expressway for 20 rainfall events. COD, SS, nutrients (N, P), and heavy metals (Pb, Zn, Cu) were analyzed for total 236 runoff samples. The event mean concentration (EMC) showed large variations, 23.2~592.4 NTU (turbidity), 20.4~341.6 mg/L (COD), 0.3~8.6 mg/L (TN), 0.01~2.4 mg/L (TP), 20.6~413.1 mg/L (SS), 22.8~905.4 μg/L (Pb), 37.8~1,668 μg/L (Zn), and 73.5~372.3 μg/L (Cu), respectively. The individual pollutants concentrations as well as the EMC were governed by the cumulative rainfall depth, a major consideration to design runoff control facilities. A remarkable contribution of this study occurred in maximum divergence point (MDP) analysis to assess the degree of first flush. The first flush appeared generally when the rainfall depths exceeded 20 mm, while MDP appeared at 25 to 30% of total runoff volume. SS concentration was found to have significant correlation with COD, TP, Pb and Cu concentration. A principal component analysis further demonstrated that the particle concentration contributed to the variability of runoff water quality.