The Research On Pavement Sediment Of Highway And Runoff Pollution Characteristic

As the rapid development of highway, the environmental issues around it comeinto being continuously, especially the non-point source pollution caused by rainfallrunoff. Inorder to prevent the surface water bodies from polluted by rain runoff anddiscuss the pollution characteristics and regulation of pollutants discharge of roadrain runoff, the West Chang Tan highway in Hunan province is taken as the researchobject in the paper. The pavement sediments and rain runoff samples of the highwayare analyzed, the characteristic of pavement sediments and rain runoff are dissected.The impact of the earth’s surface runoff on receiving water bodies is also discussed.The main conclusions of this study are shown as followed:By analyzing of road surface sediment samples, it presented alkaline. The sizedistributions of pavement sediments were generally less than0.3mm. The content ofCOD in smaller particles was higher than that of larger particles and the averageconcentrations of COD were between10.56mg/g and28.26mg/g. The concentrationsof heavy metals (Cu, Zn, Pb, Cd) in particles with diameter less than0.15mm weregenerally exceeded standards of the selected soil value. The content of organicmatters in sediments had certain influence on adsorption of heavy metals. The highercontent of organic matters was, the higher content of heavy metals would be.The results of samples monitoring in surface runoff showed that the averageconcentration of SS and COD of toll road surface runoff samples were about70,585mg/L respectively, and the service gas station were about120,357mg/L, in whichSS and COD were the primary pollutants. Due to the differences of catchment area,the first flush phenomenon didn’t happen in toll station while the FFE existed inservice station and the FFE of COD was most obviously. There were significant linearrelations among the water parameters with a correlation coefficient exceeded0.7between SS and other parameters. BOD5/COD of the runoff was about0.11whichreflected the poor biodegradability.The annual pollutant load method is one useful way to study the impact of runoffon receiving water bodies. The pollutant load contents of SS, COD, BOD5, P, N, Cu,Zn, Pb, Cd were7143.3kg/hm·year,898.67kg/hm·year,91.365kg/hm·year,0.81kg/hm·year,24.31kg/hm·year,1.1521kg/hm·year,4.9542kg/hm·year,0.4478kg/hm·year,0.0058kg/hm·year respectively. In addition, by analyzing of samples monitoring in receiving water bodies, water quality became worse after rainfall. Theresults show that the road surface runoff has certain effect on receiving water bodies.Road cleaning, controlling the use of deicer, vegetation control, wet detentionpond, infiltration system and wetland are some effective runoff management methods.In fact, we should take different kinds of factors into account so that best controlmethods will be selected in the future.On account of the limited condition, thesampling frequencies and the sampling sites within the study were not too much, sothe final results need further confirmation. However, the study results can providesome fundamental material and methods to environmental administrated departmentin order to control non-point source pollution and protect our environment moreeffectively. It also provides some other methods for environmental protectiondepartment to assess the impact that highway construction brings to waterenvironment.