Study on characterization of urban runoff pollution in Beijing

In this research,we studied the characterization of urban runoff pollution in Beijing through measuring water quality of urban runoff.Results showed that if going into any surface water,urban runoff of Beijing would pollute it. And most indexes of water quality of urban runoff already reached third-level standard of integrated wastewater discharge.Concentrations of TN,TP,COD_(Cr),BOD_5 of street runoff were higher than that of roof runoff and concentrations of SS of street runoff were lower than that of roof runoff.Percentage of TP linked to particles was the largest,which in street runoff was 83.1%,and which in roof runoff was 68.6%.Percentage of COD_(Cr) linked to particles was the second large,and percentage of TN linked to particles was lower relatively.Suspended solids removal,through settling or filtration,would cause an important reduction of pollutants loads in all types of runoff.The trend of change of all pollutants followed the time of rain was that concentrations of pollutants in early runoff were higher,and by the extend of time of rain,concentrations of pollutants descended gradually and approached to the stabilization.Early runoff was very harmful.