Treatment Effects of Vermiculite with Gravel System on Road Runoff

In order to investigate the effect of vermiculite with gravel on road runoff, we research the removal efficiency of road runoff pollutant with the combination of different sizes of gravel with vermiculite, through the indoor simulation experiment. The road runoff pollutant indexes include potential of hydrogen (pH), suspended solids (SS), biochemical oxygen demand after 5 days (BOD5), chemical oxygen demand (COD), petroleum and heavy metals (including Cu, Zn and Pb). The results show that the combined decontamination materials have the effect of adjusting pH, the removal rate of suspended solids is from 25.00% to 92.31%, heavy metals´ removal rate is30.51% to 70.50%, the removal rate of COD is 20.43% to 60.10%, the removal rate of BOD5 is 20.00% to 60.00%, the removal rate of petroleum is 33.85% to 77.85%.For the same kind of vermiculite, after the treatment of sewage with the combination, the concentration of each combination of pollutants shows gradual downtrend with the decrease of gravel sizes, but the removal rate of accumulation of pollutants increases gradually.