The Potential Pollution Risk of Groundwater by a Ceramic Permeable Brick Paving System

Abstract

To investigate the potential pollution risk of permeable brick paving systems in areas with high groundwater levels, a system was constructed by using ceramic permeable bricks as the surface and a Chinese character “well”-shaped frame as the base on the top of a 1.0 m clay layer. The concentrations of total suspended solids (TSS), total phosphorus (TP), ammonia nitrogen (NH4+-N), total nitrogen (TN), chemical oxygen demand (COD), and heavy metals (Zn, Cu, and Pb) at different underground depths were measured, the potential pollution of the groundwater was assessed, and the effectiveness of the fillers inside the frame for improving the quality of the groundwater was discussed. The results showed that NH4+-N and COD concentrations detected at the depth of 0.6 m were higher than that of the national standard for groundwater (GBT14848-2017), these two pollutants had the potential pollution risk. The pollution risk by heavy metals was comparatively low because most of the heavy metals were likely retained in the surface soil by adsorption, complexation, and precipitation, while the pollution risk by TSS and TP was negligible due to the good purification ability in the clay layer. The results suggest that the removal rates of TSS, TP, TN, COD, and heavy metals can be improved by appropriate fillers’ adjustment, such as iron filings, coal slag, or volcanic rocks. This research offers a new perspective on the potential risk of pollution and the governance of groundwater.