Abstract: A comparative test of runoff pollutant removal was carried out for 4 different substrates. These 4 different substrates were coarse river sand （particle size of 1.00~2.00 mm）, fine river sand （particle size of 0.15~0.60 mm）, coarse quartz sand （particle size of 1.00~2.00 mm） and fine quartz sand （particle size of 0.50~1.00 mm）. The conventional sandy loam （particle size of 0.02~0.20 mm） was used as the control. The results showed that when the initial concentration of total nitrogen was 20 mg/L, the four substrates had the highest removal rate of total nitrogen. When the initial concentration of total phosphorus was 40 mg/L, the removal rate of total phosphorus by the four substrates was the highest. With the increase of the initial concentration of pollutants, the removal rate of pollutants by the four substrates had a significant downward trend. In general, the removal rate of pollutants by coarse quartz sand and fine river sand was higher than that of the other two materials. In terms of adsorption capacity, except for fine river sand, the adsorption capacity of the other three substrates to pollutants increased firstly and then tended to be stable with the increase of initial concentration of pollutants, while fine river sand showed good adsorption potential at high concentration. According to the analysis, the main reason was that river sand removed pollutants through physical adhesion, which was mainly affected by surface area, while quartz sand intercepted pollution through chemical adsorption, and the main control factor was porosity. Therefore, river sand with large specific surface area and quartz sand with large porosity had more obvious intercepting effect.

Key words: permeable pavement base, aggregate, runoff pollutants, removal rate, adsorption capacity