Effects of subbase materials on phosphorous attenuation in permeable pavement system and correlation between pollution attenuation and subbase materials

In this study, laboratory models of six permeable pavement system (PPS) columns with various subbase configurations were examined for phosphorus attenuation. Experiments were carried out under varying intensities and durations of rainfall to investigate possible PPS modifications to enhance the performance of phosphorus attenuation and the likelihood of phosphorus leaching back to infiltration. The results show the inefficiencies of phosphate attenuation in the conventional PPS structure. During long-duration rainfall events, phosphates can be leached back to the infiltrate through the conventional PPS structure. The intensity of rainfall affects the attenuation of total phosphorus through the six permeable pavement columns. To achieve an enhanced phosphate attenuation, the findings of this study suggest modifying the PPS structure by incorporating thin sand layers in the subbase. Also, the correlation between pollutant attenuation and subbase materials is found. Finally, design modification of PPS is recommended to enhance the pollutant attenuation capacity of the PPS.