Water Quality Characteristics Of Stormwater Runoff And Correlation Analysis Of Pollutants Index In Baishazhou Avenue, Wuhan

The stormwater pollution control and stormwater reuse technology are the most popularresearch subjects all over the world in recent years. It shows great significance to study thecharacteristics of road rainwater runoff in the cities and monitor the indexes of pollutants forknowing the pollution status and changing rule,controlling rainwater pollution and selectingdetailed reuse programs. The purpose of this study is to master the pollution characteristics ofroad rainwater runoff in Wuhan City and provide experimental database for choosing technicalparameters in the early stormwater pollution prevention and stormwater reuse technology.This study selected Baishazhou Avenue in Wuhan as sampling site and rainwater samplesfrom ten rainfall events were collected. The main research contents included: The monitoringand statistical analysis of the major pollution indicators including COD, BOD₅, SS, TN, TP,NH3-N; the correlations analysis of the indexes; and the effect of settlement on pollutionindexes.The study results showed that:（1）Road runoff pollutant concentration has significant initial effect. The values wereaffected by the accumulated sunny days, rainfall, rainfall intensity and seasonal factors. Thelonger accumulated sunny days showed higher pollutants concentration; the overall trend wentdownward with the extension of rainfall; but the late runoff concentration also showed a fewsmall peak after stabilized in the traffic arteries; the runoff from high intensity rainfall hadbetter quality than small and medium-intensity rainfall; Due to the influence of road material,the runoff had better quality in autumn and winter than in summer.（2）The EMC values of the pollutant index SS, COD, BOD₅, TN, NH3-N and TP are120～414mg/L,123～535mg/L,63～139mg/L,9.3～22.9mg/L,7.3～21.2mg/L,9.3～22.9mg/Lrespectively. Except TN, other indexes showed normal distribution and significant correlationamong the various indicators. Through the linear fit of SS and COD, BOD₅, TN, TP from the10rainfall events, the correlation were0.5993,0.5554,0.6318,0.4165respectively. By definingthe different conditions after rainfall events, the correlation improved significantly.（3）After settling for120min, the removal rate of SS, COD, BOD₅, TN, TP were61.82%,57.44%,56.89%,2.92%,52.92%respectively. Settlement had little effect on the removal of TN,the removal rate of other contaminants indexes was SS> COD> BOD₅> TP in turn, and theremoval rate of more than80%were completed within the first60minutes. The linearrelationship of the removal rate of SS with that of COD, BOD₅, TP were that:E_COD=0.829ESS+4.5506,R²=0.906;EBOD₅=0.836ESS+4.551,R²=0.878;ETP=0.787ESS+4.441,R²=0.879. By sedimentation, the effluent quality of rainwater can meet the three grade standard ofurban sewage discharge.