The Influence of Design Parameters on Stormwater Pollutant Removal in Permeable Pavements

Abstract

Porous asphalt (PA), porous concrete (PC), and permeable inter-locking pavers (PICP) with sub-surface layers consisting of different gravel sizes (63, 40, and 12 mm) commonly used in the bedding, base, and sub-base layers of permeable pavements were investigated for their ability to remove total suspended solids (TSS), total phosphorous (TP), and total nitrogen (TN). The investigation focused on the individual surface and sub-surface layers of the three permeable pavements to “treat” these pollutants and how the physical design of these layers influences their water quality treatment performance. This assessment was conducted with a laboratory study, but performances were also compared to data obtained from a field-scale study of pollutant removal in PA, PC, and PICP. Pollutant removal by a sub-surface layer and the particle size distribution of outflow are dependent on both the thickness of the layer and the gravel size. Superior performance in removing pollutants was found in PC’s surface layer compared to the surface layers of PA and PICP. The lab-scale pavements and the field-scale pavements have similar performance in removing pollutants for TSS (87–95 %) and TP (75–89 %) but not for TN (3–10 % for lab-scale and 2–40 % for field-scale pavements). A simple mathematical model based on these results was developed to provide estimates of performance in the field.