Removal of Heavy Metals Using Pervious Concrete Material

Pervious concrete material has been used as an alternative to impervious concrete and other pavement materials to reduce water runoff. Pervious concrete allows water to percolate through and into the subsurface soil. Unlike other pavement systems, pervious concrete used for environmental purposes needs to not only satisfy strength and freeze-thaw requirements, but also needs to provide adequate permeability and be modified for optimal environmental benefits (i.e., reducing heavy metal and hydrocarbon concentrations). Studies have shown that passing water containing these different contaminants through pervious concrete material reduces the concentration of these contaminants. Although few, some studies have focused on the reduction of heavy metal concentrations via pervious concrete material subjected to long-term submersion in water due to bacterial growth. This study focuses on the fundamental understanding of the roles different materials constituting pervious concrete play in their interaction with heavy metals as well as the mechanisms of this interaction. A pervious concrete mixture that satisfies strength requirements generally consists of aggregate, sand, cement and admixtures. Using 24-hour batch tests with copper concentrations between 5 mg/l and 20mg/l, the interaction of materials that constitute a pervious concrete mixture as well as a pervious concrete cylindrical sample were tested. In addition to monitoring the concentration of copper for 24 hours, pH and conductivity were also measured for each of the materials and for the pervious concrete samples.