Suitability of reclaimed asphalt pavement and recycled crushed brick as filter media in bioretention applications

Bioretention systems are increasingly being used in urban stormwater management systems, whereas quarry materials are used as filter media; however the use of quarry materials in this application reduces valuable natural resources. Such a novel approach of using recycled waste materials would significantly conserve valuable natural resources. A series of laboratory tests included particle size distribution, organic content, pH, specific gravity, flakiness index and hydraulic conductivity. Among the pollutants, total suspended solid (TSS), total phosphorus (TP) and total nitrogen (TN) were selected. A model for bioretention system was simulated to investigate the effectiveness of reclaimed asphalt material (RAP) and crushed brick (CB) materials in trapping selected pollutants. In terms of physical and chemical properties, RAP and CB were found to meet the stringent requirements of various environmental protection authorities. This research further indicates that recycled waste materials can be reused viably as alternative materials in bioretention systems.